Contrast media are agents used to improve visualization of internal structures that otherwise cannot be seen clearly. There are two main types - positive contrast agents that are radiopaque, and negative contrast agents that are not. Iodinated contrast media are most commonly used today. They can be ionic monomers, ionic dimers, non-ionic monomers or non-ionic dimers. The ideal contrast medium has high solubility, stability, low toxicity and viscosity, and is excreted selectively like by the kidneys. Ultrasound contrast agents contain microbubbles that enhance echogenicity and improve tissue contrast. They act by resonating within the ultrasound beam. Newer agents use more stable low solubility gases and encapsulation to increase
Contrast media are substances used to enhance the contrast of structures or fluids within the body during medical imaging. There are two main types - positive contrast agents that are high in atomic number like iodine and barium, and negative contrast agents that are low in atomic number like air. Positive contrast agents can be water soluble like iodine compounds used for intravenous injections, or water insoluble like barium sulphate used to study the gastrointestinal tract. While generally safe, contrast media do carry risks of minor or major reactions, with ionic contrast media having higher reaction probabilities than non-ionic varieties.
This document provides information about small bowel imaging techniques. It discusses barium follow through examinations, where barium is ingested and x-rays are taken periodically to image the small bowel. It also describes dedicated small bowel follow through exams using single contrast techniques and positioning to visualize different parts of the bowel. Other small bowel imaging methods discussed include enteroclysis, peroral pneumocolon, and reflux examinations. The document provides details on the indications, contraindications, and interpretation of small bowel imaging studies.
Handling the emergencies in radiology and first aid in the x ray departmentAnupam Niraula
1) Emergency departments are designed to treat acute medical issues without appointments and are staffed by trauma physicians. They classify patients into non-urgent, urgent, and acute categories to prioritize care.
2) For trauma patients, MDCT is often the preferred imaging method and should be located near the emergency room along with radiography. Interventional radiology may perform procedures like embolization to stop hemorrhaging.
3) In reaction emergencies, treatments vary based on symptoms but may include oxygen, antihistamines, epinephrine, saline, and moving the patient to stabilize their condition. Staff are trained to recognize and respond to different types and severities of reactions.
Contrast media and medical imaging part 1Gopal Panda
Medical imaging uses contrast agents to improve visualization of internal organs and tissues. Contrast agents work by absorbing or altering electromagnetic waves or ultrasound, enhancing the contrast between tissues in images. India has a large and varied radiology market to serve its large population, but relatively few radiologists per capita. The major modalities used are X-ray, ultrasound, CT, and MRI. Contrast agents improve visibility of structures for these modalities. The most common types are iodine-based agents for X-ray and gadolinium for MRI; ultrasound uses microbubbles. Iodine-based agents are classified based on iodine concentration and osmolarity.
This document provides an overview of venography, which is an imaging technique used to examine veins. It discusses the basic principles of venography, including ascending and descending techniques. It describes the anatomy of veins and provides diagrams. It also covers indications, contraindications, techniques, and potential complications of lower limb, upper limb, and peripheral varicography venography procedures. The goal of venography is to accurately diagnose conditions like deep vein thrombosis.
Contrast agents are substances used in radiography to improve visualization of internal structures. They can be radiopaque (positive contrast) or non-radiopaque (negative contrast). Iodinated contrast media are commonly classified based on their ionicity, osmolality, and viscosity. Low osmolar contrast media including non-ionic dimers and monomers are preferred due to their favorable safety profile. Ultrasound contrast agents contain microscopic gas-filled bubbles that strongly reflect ultrasound waves, increasing echogenicity and tissue contrast.
1. Single slice CT acquires one slice at a time requiring longer acquisition times, while multi-slice CT acquires multiple slices per rotation allowing a larger volume to be scanned more quickly with less motion artifacts.
2. Multi-slice CT uses a detector array segmented in the z-axis to acquire multiple slices simultaneously, while single slice CT uses a long narrow detector array. This allows multi-slice CT to reconstruct images at various thicknesses and intervals.
3. Applications of multi-slice CT include faster whole organ and cardiac imaging, virtual endoscopy, isotropic imaging, and CT angiography due to its ability to acquire multiple slices simultaneously in a shorter time period.
Contrast media are substances used to enhance the contrast of structures or fluids within the body during medical imaging. There are two main types - positive contrast agents that are high in atomic number like iodine and barium, and negative contrast agents that are low in atomic number like air. Positive contrast agents can be water soluble like iodine compounds used for intravenous injections, or water insoluble like barium sulphate used to study the gastrointestinal tract. While generally safe, contrast media do carry risks of minor or major reactions, with ionic contrast media having higher reaction probabilities than non-ionic varieties.
This document provides information about small bowel imaging techniques. It discusses barium follow through examinations, where barium is ingested and x-rays are taken periodically to image the small bowel. It also describes dedicated small bowel follow through exams using single contrast techniques and positioning to visualize different parts of the bowel. Other small bowel imaging methods discussed include enteroclysis, peroral pneumocolon, and reflux examinations. The document provides details on the indications, contraindications, and interpretation of small bowel imaging studies.
Handling the emergencies in radiology and first aid in the x ray departmentAnupam Niraula
1) Emergency departments are designed to treat acute medical issues without appointments and are staffed by trauma physicians. They classify patients into non-urgent, urgent, and acute categories to prioritize care.
2) For trauma patients, MDCT is often the preferred imaging method and should be located near the emergency room along with radiography. Interventional radiology may perform procedures like embolization to stop hemorrhaging.
3) In reaction emergencies, treatments vary based on symptoms but may include oxygen, antihistamines, epinephrine, saline, and moving the patient to stabilize their condition. Staff are trained to recognize and respond to different types and severities of reactions.
Contrast media and medical imaging part 1Gopal Panda
Medical imaging uses contrast agents to improve visualization of internal organs and tissues. Contrast agents work by absorbing or altering electromagnetic waves or ultrasound, enhancing the contrast between tissues in images. India has a large and varied radiology market to serve its large population, but relatively few radiologists per capita. The major modalities used are X-ray, ultrasound, CT, and MRI. Contrast agents improve visibility of structures for these modalities. The most common types are iodine-based agents for X-ray and gadolinium for MRI; ultrasound uses microbubbles. Iodine-based agents are classified based on iodine concentration and osmolarity.
This document provides an overview of venography, which is an imaging technique used to examine veins. It discusses the basic principles of venography, including ascending and descending techniques. It describes the anatomy of veins and provides diagrams. It also covers indications, contraindications, techniques, and potential complications of lower limb, upper limb, and peripheral varicography venography procedures. The goal of venography is to accurately diagnose conditions like deep vein thrombosis.
Contrast agents are substances used in radiography to improve visualization of internal structures. They can be radiopaque (positive contrast) or non-radiopaque (negative contrast). Iodinated contrast media are commonly classified based on their ionicity, osmolality, and viscosity. Low osmolar contrast media including non-ionic dimers and monomers are preferred due to their favorable safety profile. Ultrasound contrast agents contain microscopic gas-filled bubbles that strongly reflect ultrasound waves, increasing echogenicity and tissue contrast.
1. Single slice CT acquires one slice at a time requiring longer acquisition times, while multi-slice CT acquires multiple slices per rotation allowing a larger volume to be scanned more quickly with less motion artifacts.
2. Multi-slice CT uses a detector array segmented in the z-axis to acquire multiple slices simultaneously, while single slice CT uses a long narrow detector array. This allows multi-slice CT to reconstruct images at various thicknesses and intervals.
3. Applications of multi-slice CT include faster whole organ and cardiac imaging, virtual endoscopy, isotropic imaging, and CT angiography due to its ability to acquire multiple slices simultaneously in a shorter time period.
This document discusses portable and mobile x-ray machines. Portable x-rays can be carried by one person and used in hospitals, distant locations, or patients' homes to image in-patients or guide surgeons. Mobile x-rays are larger wheeled units that can be motorized or pushed. They have components like a base, generator, control panel, and supported x-ray tube. Mobile x-rays are classified by power source like capacitor discharge or batteries, and by output like low, average, or high power. Capacitor discharge units use a charged capacitor as the power source, while battery powered units use rechargeable batteries. Safety precautions for portable and mobile x-rays include long exposure cables and lead protection
This document discusses the history and evolution of different generations of computed tomography (CT) technology. It describes the key limitations and innovations of each generation from the first generation CT scanner created in 1971, which took 5 minutes to produce an image, to modern multi-slice CT scanners. The higher the generation number, the faster imaging times and more slices that could be acquired simultaneously. However, a higher generation does not always indicate a higher performance system.
This document provides an overview of contrast media including its introduction, mechanism of action, basic chemistry and properties, classifications, commonly used preparations, pharmacodynamics, interactions with body systems, potential side effects and their management, and prevention strategies. Contrast media helps improve visualization of tissues during medical imaging by increasing beam attenuation. Iodine is commonly used as the contrast agent due to its high atomic number. Both ionic and non-ionic varieties exist with different properties. Potential side effects range from minor to severe reactions.
This document provides information on contrast media used in radiology, including barium sulfate, gadolinium-based contrast agents, and ultrasound contrast agents. It discusses the properties, uses, advantages, and disadvantages of different non-iodinated and iodinated contrast media. Specific contrast agents are described in detail, along with their mechanisms of action, safety considerations, and future directions for contrast media.
This document discusses emergency drugs used in radiology departments. It notes that medical emergencies may occur due to medications, procedures, or pre-existing conditions. A crash cart containing emergency drugs like adrenaline, atropine, buscopan, hydrocortisone, and dopamine is used to manage complications from sedation, invasive procedures, or errors. While serious emergencies are rare, the increasing complexity of procedures means they will become more frequent. It is essential that radiology departments are prepared to deal with any emergency immediately. The presentation will discuss emergency drugs and their uses.
Adverse reactions and management of contrast reactions Ashim Budhathoki
The document provides information on contrast media used in medical imaging. It begins with acknowledging those who helped with the project. It then discusses the objectives of the study which are to define contrast media, explain types and reactions, and responsibilities during contrast studies. The document classifies contrast media as positive or negative. Positive contrast media make structures appear brighter on images while negative contrast media make structures appear darker. It provides details on various contrast agents used for different medical imaging modalities like CT, MRI, ultrasound and their routes of administration.
Magnification(macro and micro radiography), distortionparthajyotidas11
This document discusses the techniques of macroradiography and microradiography. It defines macroradiography as producing a magnified image using increased object to film distance. It describes the principles of magnification using fixed focus-film distance or fixed focus-object distance. Unsharpness from movement or geometry is discussed. Applications include skull and wrist radiography. Microradiography uses ultra-fine film and high voltages for small object imaging. Mass miniature radiography was used to screen for tuberculosis using portable fluoroscopic equipment. Distortion can occur if objects are not parallel to the central x-ray beam.
This document discusses various types of artifacts that can occur in ultrasound imaging. Artifacts arise due to errors in how the ultrasound beam interacts with tissues and assumptions made in image processing. They include beam width and side lobe artifacts from beam characteristics, reverberation and comet tail artifacts from multiple echoes, speed displacement and refraction artifacts from velocity errors, shadowing and increased through transmission from attenuation errors, and mirror images from incorrect assumptions. Understanding artifacts can provide clues to tissue composition and aid diagnosis by improving image quality.
This document discusses magnetic resonance angiography (MRA) and its advantages and disadvantages compared to catheter angiography. It describes different MRA techniques including contrast enhanced MRA, time of flight angiography, phase contrast angiography, and non-contrast techniques. It also discusses artifacts that can appear on MRA such as metal artifacts and blooming artifacts. Key features and images of each technique are provided.
This document discusses various types of artifacts that can occur in ultrasound imaging. It defines an artifact as any part of an image that does not accurately represent the anatomical structures present. Some key artifacts mentioned include acoustic enhancement, acoustic shadowing, anisotropy, beam width artifact, blooming artifact, comet tail artifact, electrical interference artifact, mirror image artifact, multipath artifact, and reverberation artifact. Each artifact is described in terms of what structures or situations can cause it and how it affects the ultrasound image. Understanding artifacts is important for proper image interpretation.
MRI artifacts can occur due to hardware issues, software problems, physiological phenomena or physical limitations of the MRI device. Common artifacts include chemical shift artifacts seen at fat-water interfaces, aliasing artifacts due to an undersized field of view, black boundary artifacts at tissue borders, and motion artifacts from patient movement. Understanding the sources and appearances of artifacts is important for technicians to maintain image quality and avoid confusing artifacts with pathology.
This document provides information about barium swallow procedures, including:
- Barium is the preferred contrast agent for upper GI procedures due to its superior contrast qualities.
- Properties of ideal barium preparations include being highly dense, stable in suspension, and having low melting characteristics.
- A barium swallow examines the esophagus, GE junction, and detects conditions like hernias, varices, and reflux.
- Techniques include single and double contrast, prone positioning, and maneuvers to induce reflux. Water soluble agents are used if perforation or aspiration is suspected.
This document provides an overview of contrast media used in radiology. It discusses the history of contrast media beginning with their discovery in 1896. It then covers the basics of contrast media including their physiology, modes of administration, classifications for different imaging modalities, and examples of agents used for X-ray/CT, ultrasound, and MR imaging. Specific contrast agents are described in detail including their properties, uses, and side effects. The document emphasizes the importance of using lower osmolar iodinated contrast media to reduce risks when possible.
Fusion imaging refers to combining two or more imaging modalities, such as ultrasound with CT or MRI, to provide improved diagnostic accuracy. This document discusses several hybrid imaging combinations, including PET-CT and SPECT-MRI. Fusion imaging allows for precise monitoring of interventional procedures while reducing radiation exposure. The process of fusing real-time ultrasound with MR images during hepatic interventions is described, along with applications for biopsy and ablation of liver lesions not clearly visible on ultrasound alone. Limitations include the need for a prior CT/MRI and challenges with synchronizing the images.
This document discusses different types of ultrasound transducers and systems. It describes linear array, sector, and vector array transducers. It also discusses mechanical transducers, electronically steered systems, and phased array transducers. Finally, it outlines several specialized ultrasound transducers including those used for small parts, endocavity, transesophageal, transluminal, and intracardiac applications.
INTRAVENOUS UROGRAM OR INTRAVENOUS PYELOGRAMThis presentation covers in detail about the anatomy, patient preparation, procedure and pathologies.
It contains lots of images and timings for imaging.
you can look into this presentation for more ideas about IVU/ IVP.
-THANK YOU-
Ultrasound contrast agents rely on the different ways sound waves are reflected at interfaces between substances. Commercially available contrast media are gas-filled microbubbles administered intravenously, which have a high echogenicity compared to soft tissues. Contrast-enhanced ultrasound can image blood perfusion in organs and measure blood flow. Microbubbles are around 1-4 μm, similar to red blood cell size, and consist of a gas core surrounded by a lipid shell. Non-targeted contrast agents remain in circulation temporarily, while targeted agents are designed to bind specific molecules expressed in tissues of interest. Contrast imaging techniques include linear and nonlinear methods.
Barium follow through & small bowel enema ranjuRABIN PAUDEL
The document discusses barium follow through, which examines the small bowel from the duodenum to the ileocecal region by administering barium orally. It can be done as a continuation of an upper GI series or separately. Methods include single or double contrast. Double contrast uses an effervescent agent to better distend and separate bowel loops. The procedure involves preliminary films, administering contrast, and taking films over several hours to follow the barium through the small bowel. It is used to evaluate conditions like Crohn's disease and complications include leakage from an undetected perforation.
This document discusses various components of an MRI system including magnets, RF coils, gradient coils, and safety considerations. It describes the different types of magnets used in MRI like permanent, resistive, and superconducting magnets. It explains the purpose and types of RF coils and gradient coils used to generate the magnetic field gradients needed for spatial encoding in MRI. Safety aspects such as screening for metallic objects, specific absorption rate limits, and absolute contraindications for MRI are also summarized.
This document discusses various contrast agents used in medical imaging. It begins by defining contrast agents and describing their classification. It then focuses on water soluble iodinated contrast agents, describing their physiology and classifications including conventional high osmolar agents, low osmolar agents, and iso-osmolar agents. The document also discusses ultrasound contrast agents, their generations and mechanisms of action. It concludes by covering MR contrast agents such as gadolinium chelates and their uses and properties.
This document discusses portable and mobile x-ray machines. Portable x-rays can be carried by one person and used in hospitals, distant locations, or patients' homes to image in-patients or guide surgeons. Mobile x-rays are larger wheeled units that can be motorized or pushed. They have components like a base, generator, control panel, and supported x-ray tube. Mobile x-rays are classified by power source like capacitor discharge or batteries, and by output like low, average, or high power. Capacitor discharge units use a charged capacitor as the power source, while battery powered units use rechargeable batteries. Safety precautions for portable and mobile x-rays include long exposure cables and lead protection
This document discusses the history and evolution of different generations of computed tomography (CT) technology. It describes the key limitations and innovations of each generation from the first generation CT scanner created in 1971, which took 5 minutes to produce an image, to modern multi-slice CT scanners. The higher the generation number, the faster imaging times and more slices that could be acquired simultaneously. However, a higher generation does not always indicate a higher performance system.
This document provides an overview of contrast media including its introduction, mechanism of action, basic chemistry and properties, classifications, commonly used preparations, pharmacodynamics, interactions with body systems, potential side effects and their management, and prevention strategies. Contrast media helps improve visualization of tissues during medical imaging by increasing beam attenuation. Iodine is commonly used as the contrast agent due to its high atomic number. Both ionic and non-ionic varieties exist with different properties. Potential side effects range from minor to severe reactions.
This document provides information on contrast media used in radiology, including barium sulfate, gadolinium-based contrast agents, and ultrasound contrast agents. It discusses the properties, uses, advantages, and disadvantages of different non-iodinated and iodinated contrast media. Specific contrast agents are described in detail, along with their mechanisms of action, safety considerations, and future directions for contrast media.
This document discusses emergency drugs used in radiology departments. It notes that medical emergencies may occur due to medications, procedures, or pre-existing conditions. A crash cart containing emergency drugs like adrenaline, atropine, buscopan, hydrocortisone, and dopamine is used to manage complications from sedation, invasive procedures, or errors. While serious emergencies are rare, the increasing complexity of procedures means they will become more frequent. It is essential that radiology departments are prepared to deal with any emergency immediately. The presentation will discuss emergency drugs and their uses.
Adverse reactions and management of contrast reactions Ashim Budhathoki
The document provides information on contrast media used in medical imaging. It begins with acknowledging those who helped with the project. It then discusses the objectives of the study which are to define contrast media, explain types and reactions, and responsibilities during contrast studies. The document classifies contrast media as positive or negative. Positive contrast media make structures appear brighter on images while negative contrast media make structures appear darker. It provides details on various contrast agents used for different medical imaging modalities like CT, MRI, ultrasound and their routes of administration.
Magnification(macro and micro radiography), distortionparthajyotidas11
This document discusses the techniques of macroradiography and microradiography. It defines macroradiography as producing a magnified image using increased object to film distance. It describes the principles of magnification using fixed focus-film distance or fixed focus-object distance. Unsharpness from movement or geometry is discussed. Applications include skull and wrist radiography. Microradiography uses ultra-fine film and high voltages for small object imaging. Mass miniature radiography was used to screen for tuberculosis using portable fluoroscopic equipment. Distortion can occur if objects are not parallel to the central x-ray beam.
This document discusses various types of artifacts that can occur in ultrasound imaging. Artifacts arise due to errors in how the ultrasound beam interacts with tissues and assumptions made in image processing. They include beam width and side lobe artifacts from beam characteristics, reverberation and comet tail artifacts from multiple echoes, speed displacement and refraction artifacts from velocity errors, shadowing and increased through transmission from attenuation errors, and mirror images from incorrect assumptions. Understanding artifacts can provide clues to tissue composition and aid diagnosis by improving image quality.
This document discusses magnetic resonance angiography (MRA) and its advantages and disadvantages compared to catheter angiography. It describes different MRA techniques including contrast enhanced MRA, time of flight angiography, phase contrast angiography, and non-contrast techniques. It also discusses artifacts that can appear on MRA such as metal artifacts and blooming artifacts. Key features and images of each technique are provided.
This document discusses various types of artifacts that can occur in ultrasound imaging. It defines an artifact as any part of an image that does not accurately represent the anatomical structures present. Some key artifacts mentioned include acoustic enhancement, acoustic shadowing, anisotropy, beam width artifact, blooming artifact, comet tail artifact, electrical interference artifact, mirror image artifact, multipath artifact, and reverberation artifact. Each artifact is described in terms of what structures or situations can cause it and how it affects the ultrasound image. Understanding artifacts is important for proper image interpretation.
MRI artifacts can occur due to hardware issues, software problems, physiological phenomena or physical limitations of the MRI device. Common artifacts include chemical shift artifacts seen at fat-water interfaces, aliasing artifacts due to an undersized field of view, black boundary artifacts at tissue borders, and motion artifacts from patient movement. Understanding the sources and appearances of artifacts is important for technicians to maintain image quality and avoid confusing artifacts with pathology.
This document provides information about barium swallow procedures, including:
- Barium is the preferred contrast agent for upper GI procedures due to its superior contrast qualities.
- Properties of ideal barium preparations include being highly dense, stable in suspension, and having low melting characteristics.
- A barium swallow examines the esophagus, GE junction, and detects conditions like hernias, varices, and reflux.
- Techniques include single and double contrast, prone positioning, and maneuvers to induce reflux. Water soluble agents are used if perforation or aspiration is suspected.
This document provides an overview of contrast media used in radiology. It discusses the history of contrast media beginning with their discovery in 1896. It then covers the basics of contrast media including their physiology, modes of administration, classifications for different imaging modalities, and examples of agents used for X-ray/CT, ultrasound, and MR imaging. Specific contrast agents are described in detail including their properties, uses, and side effects. The document emphasizes the importance of using lower osmolar iodinated contrast media to reduce risks when possible.
Fusion imaging refers to combining two or more imaging modalities, such as ultrasound with CT or MRI, to provide improved diagnostic accuracy. This document discusses several hybrid imaging combinations, including PET-CT and SPECT-MRI. Fusion imaging allows for precise monitoring of interventional procedures while reducing radiation exposure. The process of fusing real-time ultrasound with MR images during hepatic interventions is described, along with applications for biopsy and ablation of liver lesions not clearly visible on ultrasound alone. Limitations include the need for a prior CT/MRI and challenges with synchronizing the images.
This document discusses different types of ultrasound transducers and systems. It describes linear array, sector, and vector array transducers. It also discusses mechanical transducers, electronically steered systems, and phased array transducers. Finally, it outlines several specialized ultrasound transducers including those used for small parts, endocavity, transesophageal, transluminal, and intracardiac applications.
INTRAVENOUS UROGRAM OR INTRAVENOUS PYELOGRAMThis presentation covers in detail about the anatomy, patient preparation, procedure and pathologies.
It contains lots of images and timings for imaging.
you can look into this presentation for more ideas about IVU/ IVP.
-THANK YOU-
Ultrasound contrast agents rely on the different ways sound waves are reflected at interfaces between substances. Commercially available contrast media are gas-filled microbubbles administered intravenously, which have a high echogenicity compared to soft tissues. Contrast-enhanced ultrasound can image blood perfusion in organs and measure blood flow. Microbubbles are around 1-4 μm, similar to red blood cell size, and consist of a gas core surrounded by a lipid shell. Non-targeted contrast agents remain in circulation temporarily, while targeted agents are designed to bind specific molecules expressed in tissues of interest. Contrast imaging techniques include linear and nonlinear methods.
Barium follow through & small bowel enema ranjuRABIN PAUDEL
The document discusses barium follow through, which examines the small bowel from the duodenum to the ileocecal region by administering barium orally. It can be done as a continuation of an upper GI series or separately. Methods include single or double contrast. Double contrast uses an effervescent agent to better distend and separate bowel loops. The procedure involves preliminary films, administering contrast, and taking films over several hours to follow the barium through the small bowel. It is used to evaluate conditions like Crohn's disease and complications include leakage from an undetected perforation.
This document discusses various components of an MRI system including magnets, RF coils, gradient coils, and safety considerations. It describes the different types of magnets used in MRI like permanent, resistive, and superconducting magnets. It explains the purpose and types of RF coils and gradient coils used to generate the magnetic field gradients needed for spatial encoding in MRI. Safety aspects such as screening for metallic objects, specific absorption rate limits, and absolute contraindications for MRI are also summarized.
This document discusses various contrast agents used in medical imaging. It begins by defining contrast agents and describing their classification. It then focuses on water soluble iodinated contrast agents, describing their physiology and classifications including conventional high osmolar agents, low osmolar agents, and iso-osmolar agents. The document also discusses ultrasound contrast agents, their generations and mechanisms of action. It concludes by covering MR contrast agents such as gadolinium chelates and their uses and properties.
basics of contrastmedia-171027192651.pdfAIDA BORLAZA
This document provides an overview of contrast media used in medical imaging. It discusses the history of contrast media beginning with their discovery in 1896. It then covers the physiology of contrast agents, how they are administered and classified. Specific contrast media are described for X-ray/CT including barium sulfate and iodinated agents. Ultrasound contrast media consisting of gas-filled microbubbles are also outlined. The document provides details on the various generations of contrast agents developed for optimal imaging and safety.
This document discusses the history and use of contrast media and emergency drugs for radiology procedures. It begins by outlining the early discoveries of contrast agents from the 1890s to the 1920s. It then describes how contrast agents are administered and their properties like osmolality and viscosity. The document discusses common contrast agents like barium, iodine-based agents, and categorizes them as high vs low osmolar. It outlines risks of contrast media and expected adverse reaction rates. The document concludes by listing emergency equipment needed to treat potential severe reactions.
The document discusses the history and types of contrast media and emergency drugs used in radiology. It provides details on:
- The development of contrast media from early toxic substances like bismuth and sodium iodide to safer iodine-based agents.
- How contrast media are classified based on osmolality as high osmolar, low osmolar, and iso-osmolar, and whether they are ionic or non-ionic.
- Common reactions to contrast media ranging from mild nausea to life-threatening emergencies, and the emergency equipment and drugs needed to treat reactions.
This document provides an overview of radiographic contrast media. It discusses how contrast media enhance images by increasing the absorption of x-rays in certain tissues. It describes the ideal properties of contrast media and classifications such as iodinated versus non-iodinated, ionic versus non-ionic, monomer versus dimer. Examples are given for different types of contrast media including barium sulfate, iodinated monomers and dimers, oil-soluble agents, and MRI contrast agents containing gadolinium. The document covers the history, properties, advantages, disadvantages and examples of various contrast media used in radiology.
The document discusses contrast agents used in medical imaging, including desirable properties like safety and effectiveness, types such as positive iodine-based and negative air/gas agents, administration methods, and examples of examinations. Adverse effects are outlined for different contrast media based on properties like osmolality and ionicity. The ideal contrast agent is described as having high solubility, stability, biocompatibility, and selective excretion with minimal adverse impacts.
The document defines key terms related to contrast agents used in radiology, including their chemical properties and classifications. It discusses:
- Osmosis, dialysis, and tonicity classifications like isotonic, hypotonic, and hypertonic solutions and their effects on red blood cells.
- Properties of contrast agents like osmolality, viscosity, and ionicity. Early agents were ionic monomers and dimers while later non-ionic agents had fewer particles per iodine atom.
- Classifications of iodine-based contrast media by contrast agent ratio and comparisons of osmolality and viscosity. The safest have lower osmolality and viscosity.
- Descriptions of barium sulfate
1. Contrast agents are substances that have different atomic numbers or electron densities than surrounding tissues, allowing visualization of internal organs on imaging.
2. Early contrast agents included barium sulfate, iodinated compounds, and air or CO2. Modern agents are classified as ionic or non-ionic monomers and dimers with varying osmolalities and viscosities.
3. Contrast agents are used with multiple imaging modalities like CT, MRI, ultrasound, and fluoroscopy. They are administered orally, intravenously, or directly into structures. The choice depends on the physical properties and safety of the specific agent and the anatomy being imaged.
Contrast agents are used to highlight areas of the body during imaging procedures. They work by enhancing the density of tissues so they appear differently than surrounding areas. There are two main types - negative contrast agents which appear darker, and positive contrast agents which appear brighter. Barium sulfate is commonly used orally or rectally for GI studies, while iodine compounds are used for angiography and urography. Ideal contrast agents are water soluble, chemically stable, non-toxic, and selectively excreted by the kidneys. High osmolar ionic dimeric and monomeric agents can cause more adverse effects than low osmolar non-ionic variants. Newer non-ionic dimeric and monom
Here are the key steps in administering intravenous contrast media safely:
- Obtain informed consent
- Check for allergies and reactions to previous contrast administrations
- Consider risk factors like renal impairment, diabetes, or cardiac conditions
- Use low-osmolar contrast for high-risk patients
- Monitor vital signs during and after injection
- Have resuscitation equipment and medications available in case of reaction
This document discusses different types of contrast agents used in medical imaging. It describes:
1. Positive contrast agents like iodine and barium that appear white on images as they attenuate x-rays more than soft tissue. Negative contrast agents like air and CO2 appear dark as they attenuate x-rays less.
2. Iodinated contrast agents are most commonly used. They are classified as high-osmolar ionic monomers, low-osmolar ionic dimers and non-ionic monomers/dimers based on their molecular structure and osmolarity.
3. Important factors for contrast agents include water solubility, stability, biocompatibility, and renal excretion.
Radiographic Contrast Agents And Contrast-induced Nephropathy
All contrast agents have a basic structure of a benzene ring, which is composed of 6 joined carbon atoms, each of which has an attached hydrogen atom.
Contrast media consist of triiodinated benzene rings, whereby 3 hydrogen atoms are replaced with attached iodine atoms.
Monomers contain 1 triiodinated benzene ring, and dimers contain 2 triiodinated benzene rings
Iodinated contrast media are widely used in radiology to enhance images. They ideally have properties like water solubility, stability, and safety. Contrast agents have evolved from early sodium iodide to include low and iso-osmolar agents. They are excreted renally and can interact with other drugs. Guidelines recommend using the lowest necessary dose and selecting low-osmolar media for high-risk patients. While generally safe, adverse reactions still occur occasionally and require prompt treatment.
This document provides information on various intravenous contrast agents used in radiology. It discusses iodinated contrast agents used for CT imaging, classified based on their ionicity and molecular structure. Adverse reactions and safety considerations are covered. Contrast agents used for ultrasound imaging are also mentioned. The document concludes with details about MRI contrast agents, which alter proton relaxation to brighten or darken images. Paramagnetic and superparamagnetic agents commonly used are gadolinium and iron oxide particles respectively.
A brief of contrast media used in various modalities of radiodiagnosis including barium, USG, CT, and MRI with their advantages and disadvantages and ADR.
This document discusses contrast agents used in medical imaging. It begins by outlining the aims of discussing contrast agents, including why they are used and desirable features. The main types of contrast agents are then described - positive contrast agents like iodine and barium sulfate which increase attenuation, and negative contrast agents like air which decrease attenuation. Methods of administration and examples of examinations using contrast are provided. Risks associated with contrast agents like reactions and nephrotoxicity are also summarized.
CONTRAST MEDIA in diagnostic radiographyRitupanta1
Contrast media are diagnostic agents used in radiology to enhance images. There are different types including barium sulfate, which is used to examine the gastrointestinal tract, and iodinated contrast media, which contains iodine and is preferred due to its high contrast density. Iodinated contrast media can be ionic or non-ionic, and classified further based on whether they contain ionic monomers, dimers, or non-ionic monomers and dimers. The classification depends on the iodine to particle ratio in solution.
Radiographic contrast media were developed starting in the late 19th century to increase differences in tissue attenuation and improve organ visualization on radiographs. The first effective contrast agents used barium and iodine compounds. Modern contrast media are tri-iodinated benzene derivatives that are either ionic or non-ionic, and monomeric or dimeric in structure. They carry risks of both idiosyncratic and non-idiosyncratic adverse reactions that depend on their osmolality, viscosity, and other properties. Appropriate use and precautions seek to minimize risks while maximizing diagnostic value.
The document discusses various contrast media used in radiology including iodinated contrast media, barium sulfate, gadolinium, and ultrasound contrast agents. It provides classifications of contrast media based on their atomic number, water solubility, and excretion route. It describes the differences between high-osmolar and low-osmolar iodinated contrast media and their safety profiles. MRI contrast agents discussed include gadolinium chelates and their indications. The document also covers ultrasound contrast microbubbles and their encapsulation, as well as barium sulfate mixtures used for gastrointestinal imaging.
The vertebral column consists of 33 vertebrae separated by intervertebral discs. A typical vertebra has a vertebral body and arch enclosing the vertebral foramen through which the spinal cord passes. The spinal cord has 31 pairs of spinal nerves and is composed of gray and white matter. It transmits sensory information up the posterior columns and motor commands down tracts like the corticospinal tract. Injuries can cause syndromes like complete transection with bilateral deficits or Brown-Sequard with unilateral deficits depending on the location and extent of damage.
The document describes the various cerebrospinal fluid (CSF) filled spaces, or cisterns, within the subarachnoid space. It details both supra-tentorial and infra-tentorial cisterns, providing their locations, contents such as vessels and cranial nerves, and anatomical relationships. Key cisterns mentioned include the cistern of the lamina terminalis, chiasmatic cistern, interpeduncular cistern, prepontine cistern, cisterna magna, and cerebellopontine angle cistern. The cisterns form a interconnected network facilitating CSF circulation within the subarachnoid space.
This document provides an overview of the gross anatomy of the brain as seen on MR imaging. It describes the central sulcus, ventricular system, limbic system, and white matter. It then details the axial, sagittal, and coronal views of the brain and lists over 100 structures and their 3D localization within the brain.
The document discusses various congenital anomalies of the pancreas including annular pancreas, pancreas divisum, ectopic pancreatic tissue, horseshoe pancreas, and variations in pancreatic ductal anatomy. It describes the embryological development of the pancreas and defines important anatomical structures such as the pancreatic ducts. Imaging features of different pancreatic anomalies on modalities like CT, MRI, ERCP, and ultrasound are provided.
CT guided FNAC is a simple and minimally invasive technique for obtaining tissue samples from complex lung lesions for diagnosis. A study of 28 patients found CT guided FNAC to have a sensitivity of 80% and specificity of 100% for diagnosing malignancy. Complications occurred in 3 patients (12.5%) and were minor and self-resolving. CT guided FNAC is shown to be an effective and safe outpatient procedure for evaluating pulmonary nodules and masses.
CT guided FNAC is a simple and effective technique for diagnosing complex pulmonary lesions. In a study of 28 patients, CT guided FNAC had a sensitivity of 80% and specificity of 100% for diagnosing malignancy. CT scanning alone had sensitivity of 75% and specificity of 83.3% for malignancy. Complications occurred in 3 patients (12.5%) and were minor and resolved with conservative treatment. The study concluded that CT guided FNAC is a highly sensitive and specific technique for characterizing pulmonary lesions.
The document discusses various presacral lesions that can be seen on imaging. It describes the anatomy of the presacral space and then covers conditions with osteochondral origin like giant cell tumor and Ewing sarcoma. Neurogenic conditions such as neurofibromas, schwannomas, and perineural cysts are also discussed. Other lesions mentioned include dural ectasia and anterior myelomeningoceles. For each condition, the document provides details on clinical features, imaging appearance on modalities like CT and MRI, and examples of imaging findings.
Sarcoidosis is a multisystem granulomatous disease of unknown etiology characterized by non-caseating granulomas. It most commonly affects the lungs, presenting radiographically as bilateral hilar lymphadenopathy in 50% of cases and pulmonary nodules in 30-50% of cases. Other involved organs include the eyes, skin, and heart. On CT, it demonstrates enlarged lymph nodes and pulmonary nodules distributed along the bronchovascular bundles. Late stage disease can develop pulmonary fibrosis. Sarcoidosis can also involve bones, presenting as cystic lesions in the hands. Neurosarcoidosis manifests as leptomeningeal enhancement or intracranial masses.
The document describes various signs seen on imaging of the respiratory system. It defines signs such as the signet ring sign seen on CT scans of the lungs, the finger-in-glove appearance seen in allergic broncho-pulmonary aspergillosis, and the continuous diaphragm sign seen in pneumomediastinum where air outlines the entire diaphragm. It also provides details on other signs like the halo sign associated with hemorrhagic nodules, the reversed halo sign, and tree-in-bud appearance seen in conditions like tuberculosis.
1. The document defines and describes solitary pulmonary nodules, providing details on measurements, characteristics, and imaging features that help determine if a nodule is benign or malignant.
2. Malignant nodules are more likely to be larger in size, irregular or spiculated in shape, located in the upper lobes, and demonstrate rapid growth. Benign nodules often have fat, calcification, or show long-term stability.
3. Guidelines are provided for follow-up of solid versus subsolid nodules based on size, with smaller or stable nodules requiring less frequent follow-up, and suspicious nodules warranting further evaluation including PET scans or biopsy.
Esophageal webs are thin mucosal membranes that project into the esophageal lumen, causing constriction. They more commonly occur in the cervical esophagus near the cricopharyngeus muscle. Associations include Plummer-Vinson syndrome, graft-versus-host disease, and gastroesophageal reflux disease. On barium swallows, esophageal webs appear as smooth tapered concentric narrowing in the cervical esophagus.
The parathyroid glands are located posterior to the thyroid gland in the neck. Parathyroid adenomas, the most common cause of primary hyperparathyroidism, enhance vividly on arterial phase CT then wash out rapidly on delayed phase with low attenuation on non-contrast images. Localizing the adenoma precisely with 4D CT guides focused surgical treatment through a small incision. The characteristic enhancement pattern and morphology help identify ectopic adenomas located during fetal development in the mediastinum.
This document provides an overview of brain anatomy including:
1. It describes the MRI appearance of different brain tissues and structures including white matter, fat, CSF, and gray matter on different sequences.
2. It then covers the sulcal and gyral anatomy of the brain, describing the lobes, major sulci like the central sulcus and sylvian fissure, and how they can be identified.
3. The anatomy of each lobe is then covered in more detail including the surfaces and sulci that make up the frontal, parietal, occipital, and temporal lobes.
Osteomyelitis is an infection of bone that is usually caused by bacteria entering through the bloodstream or direct inoculation via injury. It can be acute, subacute, or chronic. Common symptoms include fever, pain, and swelling near the infected bone. Diagnosis involves blood tests, imaging like x-rays, MRI, and bone scans, and bone/blood cultures. Treatment consists of antibiotics tailored to the identified bacteria as well as possible surgical drainage of abscesses.
This document discusses primary retroperitoneal neoplasms, which arise outside of major retroperitoneal organs. It notes that 70-80% of retroperitoneal masses are malignant in nature. The document then categorizes and describes several specific types of solid neoplastic masses that can occur in the retroperitoneum, including mesodermal neoplasms (such as liposarcomas and leiomyosarcomas), neurogenic tumors, and others. For each type of mass, it provides details on prevalence, appearance on CT and MRI scans, characteristics, associated syndromes, and other relevant clinical information.
1. The goals of first trimester ultrasound include visualization of the gestational sac, identification of embryonic demise, determination of gestational age, and early diagnosis of fetal anomalies.
2. A normal intrauterine gestation will demonstrate a gestational sac, yolk sac, embryo, amnion, and cardiac activity on ultrasound. Measurement of the mean sac diameter, crown-rump length, and biometric measurements can be used to estimate gestational age.
3. Absence of cardiac activity along with signs of bleeding have a high probability of embryonic demise. Criteria such as large sac size without visualizing fetal structures indicate a poor pregnancy outcome.
This document discusses Legg-Calve-Perthes disease, which is avascular necrosis of the femoral head that occurs in children. It begins by describing the etiology as an ischemic episode affecting the capital femoral epiphysis, though the exact cause is unknown. The stages of the disease are then outlined based on radiographic appearance, from initial avascular necrosis to revascularization and bone remodeling. Complications including deformities of the femoral head and neck are also summarized. The document provides detailed information on the radiographic signs and classifications systems used to evaluate the progression and prognosis of Legg-Calve-Perthes disease.
X-ray grids are devices used to remove scattered radiation from radiographic images. They consist of alternating strips of lead and transparent material. Grids work by absorbing most of the multidirectional scattered radiation while allowing the directional primary radiation to pass through. Grid performance is evaluated based on primary transmission, Bucky factor, and contrast improvement factor. Proper grid selection and positioning are important to avoid grid cutoff and increased patient radiation dose. Moving grids eliminate grid line artifacts but have some disadvantages.
This document discusses fluoroscopy, including conventional fluoroscopy units and modern fluoroscopic units. It describes the key components of a fluoroscopic unit, including the image intensifier, vidicon camera, and TV monitor. It also discusses factors that influence fluoroscopic image quality such as radiation dose rates, image resolution both vertically and horizontally, and techniques to reduce image noise like frame averaging.
A fluoroscope uses x-rays and a fluorescent screen to enable direct observation of internal organs. It consists of an x-ray tube, table, and image intensifier. The image intensifier converts x-rays into visible light images and amplifies them for viewing. It works by accelerating photoelectrons emitted from a photocathode onto a phosphor screen, producing light photons and gaining brightness. Newer generations of image intensifiers use additional electron multiplication for higher sensitivity. Fluoroscopy provides real-time moving images for procedures while fluorography captures still diagnostic images.
Unlocking the mysteries of reproduction: Exploring fecundity and gonadosomati...AbdullaAlAsif1
The pygmy halfbeak Dermogenys colletei, is known for its viviparous nature, this presents an intriguing case of relatively low fecundity, raising questions about potential compensatory reproductive strategies employed by this species. Our study delves into the examination of fecundity and the Gonadosomatic Index (GSI) in the Pygmy Halfbeak, D. colletei (Meisner, 2001), an intriguing viviparous fish indigenous to Sarawak, Borneo. We hypothesize that the Pygmy halfbeak, D. colletei, may exhibit unique reproductive adaptations to offset its low fecundity, thus enhancing its survival and fitness. To address this, we conducted a comprehensive study utilizing 28 mature female specimens of D. colletei, carefully measuring fecundity and GSI to shed light on the reproductive adaptations of this species. Our findings reveal that D. colletei indeed exhibits low fecundity, with a mean of 16.76 ± 2.01, and a mean GSI of 12.83 ± 1.27, providing crucial insights into the reproductive mechanisms at play in this species. These results underscore the existence of unique reproductive strategies in D. colletei, enabling its adaptation and persistence in Borneo's diverse aquatic ecosystems, and call for further ecological research to elucidate these mechanisms. This study lends to a better understanding of viviparous fish in Borneo and contributes to the broader field of aquatic ecology, enhancing our knowledge of species adaptations to unique ecological challenges.
The ability to recreate computational results with minimal effort and actionable metrics provides a solid foundation for scientific research and software development. When people can replicate an analysis at the touch of a button using open-source software, open data, and methods to assess and compare proposals, it significantly eases verification of results, engagement with a diverse range of contributors, and progress. However, we have yet to fully achieve this; there are still many sociotechnical frictions.
Inspired by David Donoho's vision, this talk aims to revisit the three crucial pillars of frictionless reproducibility (data sharing, code sharing, and competitive challenges) with the perspective of deep software variability.
Our observation is that multiple layers — hardware, operating systems, third-party libraries, software versions, input data, compile-time options, and parameters — are subject to variability that exacerbates frictions but is also essential for achieving robust, generalizable results and fostering innovation. I will first review the literature, providing evidence of how the complex variability interactions across these layers affect qualitative and quantitative software properties, thereby complicating the reproduction and replication of scientific studies in various fields.
I will then present some software engineering and AI techniques that can support the strategic exploration of variability spaces. These include the use of abstractions and models (e.g., feature models), sampling strategies (e.g., uniform, random), cost-effective measurements (e.g., incremental build of software configurations), and dimensionality reduction methods (e.g., transfer learning, feature selection, software debloating).
I will finally argue that deep variability is both the problem and solution of frictionless reproducibility, calling the software science community to develop new methods and tools to manage variability and foster reproducibility in software systems.
Exposé invité Journées Nationales du GDR GPL 2024
Deep Behavioral Phenotyping in Systems Neuroscience for Functional Atlasing a...Ana Luísa Pinho
Functional Magnetic Resonance Imaging (fMRI) provides means to characterize brain activations in response to behavior. However, cognitive neuroscience has been limited to group-level effects referring to the performance of specific tasks. To obtain the functional profile of elementary cognitive mechanisms, the combination of brain responses to many tasks is required. Yet, to date, both structural atlases and parcellation-based activations do not fully account for cognitive function and still present several limitations. Further, they do not adapt overall to individual characteristics. In this talk, I will give an account of deep-behavioral phenotyping strategies, namely data-driven methods in large task-fMRI datasets, to optimize functional brain-data collection and improve inference of effects-of-interest related to mental processes. Key to this approach is the employment of fast multi-functional paradigms rich on features that can be well parametrized and, consequently, facilitate the creation of psycho-physiological constructs to be modelled with imaging data. Particular emphasis will be given to music stimuli when studying high-order cognitive mechanisms, due to their ecological nature and quality to enable complex behavior compounded by discrete entities. I will also discuss how deep-behavioral phenotyping and individualized models applied to neuroimaging data can better account for the subject-specific organization of domain-general cognitive systems in the human brain. Finally, the accumulation of functional brain signatures brings the possibility to clarify relationships among tasks and create a univocal link between brain systems and mental functions through: (1) the development of ontologies proposing an organization of cognitive processes; and (2) brain-network taxonomies describing functional specialization. To this end, tools to improve commensurability in cognitive science are necessary, such as public repositories, ontology-based platforms and automated meta-analysis tools. I will thus discuss some brain-atlasing resources currently under development, and their applicability in cognitive as well as clinical neuroscience.
BREEDING METHODS FOR DISEASE RESISTANCE.pptxRASHMI M G
Plant breeding for disease resistance is a strategy to reduce crop losses caused by disease. Plants have an innate immune system that allows them to recognize pathogens and provide resistance. However, breeding for long-lasting resistance often involves combining multiple resistance genes
Remote Sensing and Computational, Evolutionary, Supercomputing, and Intellige...University of Maribor
Slides from talk:
Aleš Zamuda: Remote Sensing and Computational, Evolutionary, Supercomputing, and Intelligent Systems.
11th International Conference on Electrical, Electronics and Computer Engineering (IcETRAN), Niš, 3-6 June 2024
Inter-Society Networking Panel GRSS/MTT-S/CIS Panel Session: Promoting Connection and Cooperation
https://www.etran.rs/2024/en/home-english/
The debris of the ‘last major merger’ is dynamically youngSérgio Sacani
The Milky Way’s (MW) inner stellar halo contains an [Fe/H]-rich component with highly eccentric orbits, often referred to as the
‘last major merger.’ Hypotheses for the origin of this component include Gaia-Sausage/Enceladus (GSE), where the progenitor
collided with the MW proto-disc 8–11 Gyr ago, and the Virgo Radial Merger (VRM), where the progenitor collided with the
MW disc within the last 3 Gyr. These two scenarios make different predictions about observable structure in local phase space,
because the morphology of debris depends on how long it has had to phase mix. The recently identified phase-space folds in Gaia
DR3 have positive caustic velocities, making them fundamentally different than the phase-mixed chevrons found in simulations
at late times. Roughly 20 per cent of the stars in the prograde local stellar halo are associated with the observed caustics. Based
on a simple phase-mixing model, the observed number of caustics are consistent with a merger that occurred 1–2 Gyr ago.
We also compare the observed phase-space distribution to FIRE-2 Latte simulations of GSE-like mergers, using a quantitative
measurement of phase mixing (2D causticality). The observed local phase-space distribution best matches the simulated data
1–2 Gyr after collision, and certainly not later than 3 Gyr. This is further evidence that the progenitor of the ‘last major merger’
did not collide with the MW proto-disc at early times, as is thought for the GSE, but instead collided with the MW disc within
the last few Gyr, consistent with the body of work surrounding the VRM.
ANAMOLOUS SECONDARY GROWTH IN DICOT ROOTS.pptxRASHMI M G
Abnormal or anomalous secondary growth in plants. It defines secondary growth as an increase in plant girth due to vascular cambium or cork cambium. Anomalous secondary growth does not follow the normal pattern of a single vascular cambium producing xylem internally and phloem externally.
When I was asked to give a companion lecture in support of ‘The Philosophy of Science’ (https://shorturl.at/4pUXz) I decided not to walk through the detail of the many methodologies in order of use. Instead, I chose to employ a long standing, and ongoing, scientific development as an exemplar. And so, I chose the ever evolving story of Thermodynamics as a scientific investigation at its best.
Conducted over a period of >200 years, Thermodynamics R&D, and application, benefitted from the highest levels of professionalism, collaboration, and technical thoroughness. New layers of application, methodology, and practice were made possible by the progressive advance of technology. In turn, this has seen measurement and modelling accuracy continually improved at a micro and macro level.
Perhaps most importantly, Thermodynamics rapidly became a primary tool in the advance of applied science/engineering/technology, spanning micro-tech, to aerospace and cosmology. I can think of no better a story to illustrate the breadth of scientific methodologies and applications at their best.
ESPP presentation to EU Waste Water Network, 4th June 2024 “EU policies driving nutrient removal and recycling
and the revised UWWTD (Urban Waste Water Treatment Directive)”
Nucleophilic Addition of carbonyl compounds.pptxSSR02
Nucleophilic addition is the most important reaction of carbonyls. Not just aldehydes and ketones, but also carboxylic acid derivatives in general.
Carbonyls undergo addition reactions with a large range of nucleophiles.
Comparing the relative basicity of the nucleophile and the product is extremely helpful in determining how reversible the addition reaction is. Reactions with Grignards and hydrides are irreversible. Reactions with weak bases like halides and carboxylates generally don’t happen.
Electronic effects (inductive effects, electron donation) have a large impact on reactivity.
Large groups adjacent to the carbonyl will slow the rate of reaction.
Neutral nucleophiles can also add to carbonyls, although their additions are generally slower and more reversible. Acid catalysis is sometimes employed to increase the rate of addition.
2. Contrast media are agents which permit visualization of details of internal
structure or organs that would not otherwise be demonstrable.
Classification
3. Positive contrast.-the use of a contrast material that is
radiopaque such as insoluble salt barium sulfate and a
variety of organic iodine compounds.
- Barium is used for gastrointestinal studies.
- Water-soluble, iodinated contrast media are used for
many procedures, including all types of angiography,
intravenous and retrograde urography,
hysterosalphingography, sialography , myelography ,
cholangiography etc
Negative contrast material that is not radiopaque such as air
or carbon dioxide
4. CLASSIFICATION
CONTRAST MEDIA
X-RAY & CT ULTRASOUND MRI
BaSO4 Oily CM Water soluble IODINATED CM
Hepatic excretion Renal excretion
Iopanoic acid
High osmolar low osmolar
Ionic monomers Ionic dimers Non-ionic monomers Non ionic
dimers
Diatrizoate Ioxaglic acid Iopromide
Iotrol
Iothalamate Iohexol
Iotrolon
5. BARIUM SULPHATE
• Has high atomic number 56, highly radiopaque.
• Non absorbable, non toxic.
• Insoluble in water/lipid.
• Inert to tissues.
• Can be used for double contrast studies.
• Uses: barium swallow, barium meal, barium meal follow through, enteroclysis,
barium enema
6. WATER SOLUBLE IODINATED CONTRAST MEDIA
IODINE
• Atomic number 53 & atomic weight 127
• Iodine is preferred because
*High contrast density due to high atomic number
*Allows firm binding to highly variable benzene ring
*Low toxicity
7. USEFUL FACTORS TO REMEMBER
• OSMOLALITY:- Is dependent on no. Of particles of solute in solution.
• RADIO OPACITY:- Is dependent on the iodine concentration of the solution & is
therefore dependent on the no. Of iodine atoms in each molecule of the contrast
medium.
• HIGH RADIO OPACITY & LOW OSMOLALITY ARE OF DESIRABLE
REQUIREMENTS.
• IODINE PARTICLE Ratio-the ratio of the no. Of iodine atoms per molecule to the
no. Of osmotically active particles per molecule of solute in solution is therefore a
fundamental criteria.
8. CLASSIFICATION OF IODINATED
CONTRAST MEDIA
• There are four chemical varieties of iodinated
RCM in clinical use.
• All four are tri - iodo benzene ring
derivatives with three atoms of iodine at
2,4,6 positions (in monomers) and six
atoms of iodine per molecule of the ring
anion (in dimers).
9. CLASSIFICATION OF IODINATED CONTRAST
MEDIA
1. IONIC MONOMERS (CONVENTIONAL/HIGH OSMOLAR CONTRAST
MEDIA [HOCM]).
2. IONIC DIMERS.
3. NON-IONIC MONOMERS .
4. NON-IONIC DIMERS.
Class 2, 3 , 4 are collectively known as low osmolar contrast
Medias.
10. IONIC MONOMERS (HIGH OSMOLAR
CONTRAST MEDIA [HOCM])
• All ionic monomers are salts consisting of a sodium or meglumine (n-
methyl glucamine) as the non-radio opaque cation and a tri-
iodinated benzoate as the radio opaque anion.
11. EG:-
IOTHALAMATE
• Anions consisting of a benzoic acid molecule with
three atoms of iodine firmly attached at C2, C4 &
C6.
• The c3 & c4 are connected to amines e-nh2 (r3 & r5)
which reduces toxicity & increase solubility.
• These anions include
• Diatrizoate (urograffin, angiograffin,
hypaque)
• Iothalamate (conray)
• Ioxithalamate,
• Metrizoate
• Iodamic acid
12. • Each molecule completely dissociates in water solution into two ions – one non-
radio opaque cation and one tri-iodinated radio opaque anion, giving an
iodine: particle ratio of 3 : 2
• Iodine content at 0.3 osmol/kg H2O - 70mg I/ml
• Osmolality at 280mgi2/ml - 1500 osmol/kg H2O
• LD-50 = 7(g of I/kg wt of mouse)
DISADVANTAGE : high osmolality (8 times that of plasma- 300 mosm/kg
water), responsible for the adverse effects, because of the non radiopaque
cations( na & meg)
13. DIFFERENCES B/W MEGLUMINE & SODIUM SALTS
MEGLUMINE SALTS SODIUM SALTS
• SOLUBILITY BETTER SAME, LESS IN SOME ACIDS
• VISCOSITY HIGH LOW
• TOLERANCE BETTER LESS, NAUSEA & VOMITING
• BLOOD BRAIN NO EFFECT CROSSES BBB
BARRIER
• VASCULAR EFFECTS LESS MARKED
• DIURETIC EFFECT STRONG LESS
• OPACIFICATION POOR BETTER
• BRONCHOSPASM CAUSES NO
SO CI IN ASTHMA
14. LOW OSMOLAR CONTRAST MEDIA
• IONIC DIMERS- IOXAGLATE(HEXABRIX), IOCARMATE
• Only compound, mixture of sodium and meglumine salts
• Two benzene rings (each with 3 iodine atoms) are linked by a bridge to form a large
compound, carries only one carboxyl group, so known as monoacid dimers
15. IONIC DIMERS- IOXAGLATE(HEXABRIX)
• In solution each molecule dissociates into one radio-
opaque hexa-iodinated anion and one non-radio
opaque cation (sodium and/or meglumine).
• Iodine particle ratio is 6:2 or 3:1
• Molecular weight is 1269
• Iodine content at -0.3 osmol/kg H2O- 150mg I/ml
• Osmolality at 280mgi2/ml - 560 osmol/kg H2O
• LD-50 = 12(g of I/kg wt of mouse)
Eg:-Ioxaglate
16. NON-IONIC MONOMERS
• Include iohexol (omnipaque), iopamidol,
iopromide (ultravist), ioversol, ioxilan.
• None of these molecules dissociate in
solution.
• They are tri-iodinated non-ionizing
compounds and therefore in solution they
provide three atoms of iodine to one
osmotically active particle (the entire
molecule), producing an iodine: particle
ratio of 3:1.
17. NON IONIC MONOMERS
• Iodine particle ratio is 3:1
• Molecular weight 600-800
• Iodine content at 0.3 osmol/kg H2O - 150mg I/ml
• Osmolality at 280mgi2/ml - 600 osmol/kg h2o
• Ld-50 = 22(g of i/kg wt of mouse)
Eg:- iohexol
(omnipaque)
18. NONIONIC DIMERS
*Iotrolan(isovist)
*Iodixanol (visipaque)
• Each molecule contains 2 non ionosing tri-
iodinated benzene rings linked together
• They do not ionize or dissociate in
solution.
• Each molecule therefore provides in
solution six atoms of iodine for one
molecule, i.E. An iodine:particle ratio of
6:1.
19. NONIONIC DIMERS
• Iodine particle ratio is 6:1
• Molecular weight 1550-1626
• Iodine content at 0.3 osmol/kg H2O- 300mg
I/ml
• Osmolality at 280mgi2/ml - 300 osmol/kg h2o
• Ld-50 = >>26(g of i/kg wt of mouse)
Eg:- iotrolan
20. PHARMACOKINETICS
• After intravascular injection, the contrast media are distributed
rapidly because of high capillary permeability into the
extravascular, extracellular space (whole body opacification)
(except in the central nervous system) & is simultaneously
excreted.
• Then equilibrium is reached b/w intra & extravascular space in
about 10 min. Continued excretion & re entry of contrast media
from ECF to ICF leads to decrease in plasma level.
• Plasma half life is 30 – 60 min.
• They do not enter the interior of blood cells or tissue cells and
they are rapidly excreted, with over 90 % being eliminated by
passive glomerular filtration by the kidneys within 12hrs.
21. ADDITIVES USED IN CONTRAST MEDIA
1) stabilizer – Ca or Na EDTA
2) buffers – stabilizes ph during storage – Na acid phosphates.
3) preservatives.
4) flavouring substances & emulsifiers for git media.
22. IDEAL CONTRAST MEDIA SHOULD HAVE:-
1) high water solubility.
2) heat & chemical stability (shelf life) - ideally 3-5 yrs.
3) biological inertness (non antigenic).
4) low viscosity.
5) low or iso osmolar to plasma.
6) selective excretion, like excretion by kidney is
favourable.
7) safety: ld50 (lethal dose) should be high.
8) reasonable cost.
23. IMP POINTS TO REMEMBER
• Contrast media used for myelography are non-ionic CM.
• Cm used for cerebral angiography, are cm containing only meglumine
cation.
• Cm containing only meglumine cation- conray 280, triovideo 280,
trazograff60% and angiograffin.
• Cm which cause max nausea & vomiting are – ioxaglate (hexabrix).
• Meglumine salts cause bronchospasm, so ci in bronchial asthma.
• Among newer cm, iohexol is most hyperosmolar
• Viscosity increases as conc increases & tends to be higher for big sized
molecules (dimers). High viscosity interferes with mixing of contrast media
with plasma & body fluids. Omnipaque240 has least viscosity.
• Meticulous heparinization is required during angiography as incidence of
25. IDEAL ULTRASOUND CONTRAST AGENT
• Be injectable by a peripheral vein
• Be non toxic
• Small enough to pass through pulmonary, cardiac & capillary
systems
• Stable enough to undergo the shear forces, hydrostatic pressure
changes & diameter changes
• Half life should be sufficient to allow complete examination
• Should require little preparation
26. • Contrast agents might act by their presence in the vascular system,
from where they r ultimately metabolized (blood pool agents) or by
their selective uptake in tissue after a vascular phase.
• Also called echo enhancing agents.
• These agents increase the echogenicity of blood, which heightens
the tissue contrast & allows better delineation of body cavities.
27. MECHANISM OF ACTION
• Pri mechanism of signal enhancement is microbubble backscatter,
which relates to differences in microbubble versus blood
compressibility.
• Increased echogenicity may be seen as an increased signal in color or
spectral doppler signal strength or gray scale image intensity.
• The halflife or persistence of microbubble depends on –
*size(<7um passes through pul cirltn)
*surface tension & gas diffusion across the bubble shell.
*Transducer frequency & power
• Mechanical index (MI) –peak pressure of usg beam calculated from
frequency & power of usg beam. Higher the MI, more likely the bubble
will break
28. GAS MICROBUBBLE CONTRAST
MEDIA
• Gas bubbles have a tremendous difference in acoustic impedance as compared to surrounding fluid
due to the large differences in density, elasticity and compressibility.
• Microscopic gas filled bubbles whose surface reflect sound waves.
• Their extremely high reflectivity(backscatter) arises from the fact that microbubbles easily change
their size, contracting in compression part of the ultrasonic cycle & expanding in the rarefaction part.
• Thus they resonate in the ultrasound beam when there is a mismatch b/w their diameter and
ultrasonic wavelength, which occurs for microbubbles in 2 to 7um at usg freq of 2-10 mhz
• Free gas bubbles
The bubbles may pre-exist in the liquid, or they may be created via cavitation during injection.
Solution used r saline, indocyanine green or renograffin.
Iv injection of physiological saline has been used as a contrast medium in echocardiography since the
late sixties, but the utility of free gas bubbles is highly limited due to:-
• Low stability
• Large bubble size to pass the pulmonary vasculature
29. • For gas bubbles to be used as transpulmonic contrast media, the gas bubbles should
be stable and smaller than 5 µm.
• Bubbles larger than 10 mm may transiently obstruct the capillaries and act as gas
emboli.
• Several stabilizing coatings have been developed to produce encapsulated gas
microbubble contrast media.
• The coatings include albumin(albunex), gelatin, galactose microspheres & palmitic acid
(levovist), polyglutaminic acid, lipophilic monolayer surfactants, and lipid bilayers
(liposomes).
30. GENERATIONS OF ECHO
ENHANCERS
• FIRST GEN- UNSTABILISED BUBBLES IN INDOCYANINE GREEN ,
CANT SURVIVE PULMONARY PASSAGE, THEREFORE USED ONLY
FOR CARDIAC & LARGE VEIN STUDY.
• SECOND GEN- LONGER LASTING BUBBLES COATED WITH
SHELLS OF PROTEIN, LIPIDS OR SYNTHETIC POLYMERS.
• THIRD GEN- ENCAPSULATED EMULSIONS OR BUBBLES, OFFER
HIGH REFLECTIVITY.
31. TYPES OF AGENTS
NON
ENCAPSULATED
MICROBUBBLES
• Formed by hand
agitation
• Unstable & breech
quickly
• Large size, small
fraction pass through
pul cirltn
• Adequate for right
heart visualization
ENCAPSULATED
MICROBUBBLES
Encapsulated air
Microbubbles
*Albunex
*Echovist (galactose)
*Levovist (galactose
& palmitic acid)
*Cavisomes –gas
filled cyanoacrylate
microspheres for
Liver, spleen & LN
Encapsulated
Perflurocarbon MB
*Optison: albumin
coated microspheres
that contain
Octafluropropane gas
Uses:Cardiac app
32. LOW SOLUBILITY GAS BUBBLES
• Since the effective duration of action of encapsulated air bubble
is very short, newer agents designed both to increase
backscatter enhancement further & to last longer in the blood
stream, r currently under intense development.
• Instead of air, many of these take advantage of low solublity
gases such as perfluorocarbons, having lower diffusion rate &
thereby increasing the longevity of the agent in the blood.
33. PARTICLE SUSPENSIONS OR EMULSIONS
• Several types of particles have been reported as ultrasound contrast
media
• Collagen microspheres (solid)
• Iodipamide ethyl ester (solid)
• Perfluorochemicals (inert, dense liquids).
• Perfluorocarbons lead to a large tissue impedance mismatch due to
their high density and compressibility.
• After iv injection, it can be detected in the intravascular space for
several hours. Due to the small particle size, the contrast medium
passes all capillary beds and will therefore enhance perfused tissue.
34. • Perfluorochemicals are eliminated either by phagocytosis of the
reticuloendothelial system or by evaporation in the lungs.
• Due to the selective phagocytosis, liver and spleen show late phase
enhancement.
• Particle suspensions are generally less effective than gas bubbles, and
much larger doses are needed for enhancement. Perfluorocarbons may
furthermore be less safe than the gas bubbles; a relatively high
percentage of mild allergic reactions have been shown in humans.
35. DOPPLER RESCUE:
• APPLICATION OF UCA RESULTS IN ENHANCEMENT OF COLOUR,
POWER & SPECTRAL DOPPLER WAVEFORM & THIS IMPROVES
DOPPLER IMAGING & IS TERMED AS “DOPPLER RESCUE “
36. APPLICATIONS
• Evaluating normal, increased or decreased vascularity.
• Detecting vascular stenosis & occlusions
• Improving neoplasm detection
• Analysing & characterizing tumour neovascularity
• Differentiating normal variants such as renal column of bertin from
neoplasm.
• Echocardiography – cardiac cavities, valves, coronary artery &
myocardial viability
40. ARTIFACTS
• Colour blooming – grey scale pixels are displayed as
colour pixel in areas that lack flow, occurs when high
conc of UCA is delivered by bolus inj.
• Bubble noise – audible sound accompanied on visible
spectral doppler tracing blips
• An increase (17 to 45 %) in maximum doppler shift
frequency
42. CONTRAST MEDIA USED IN
MRI
• GADOLINIUM CHELATES
• BLOOD POOL AGENTS
• LIVER CONTRAST AGENTS
• ENDOLUMINAL CONTRAST AGENTS
• TARGETED CONTRAST AGENTS
43. GADOLINIUM
• Is the standard exogenous contrast agent used in
clinical MR imaging.
• It is T1 relaxing agent and is paramagnetic.
• It belongs to lanthanide metal group with atomic
no. 64.
• It has a high spin contrast number which
produces desirable relaxivity contrast agents
• Three agents have been approved by FDA, they
are-
*Gd-HP-DO3A:gadoteridol/prohance (non ionic)
44. GADOLINIUM
• These function as extracellular contrast agents.
• They are rapidly excreted by glomerular filteration
with half lives b/w 1 – 2hrs.
• As these compounds are excreted by renal excretion,
caution shd be taken in renal impaired patients.
• 3 –5% of adverse reactions, occur in the form of
nausea
• Dose- 0.1 to 0.3mmol/kg body weight
• Disadvantages
*enhancement is non specific neither organ specific or
pathology specific.
*Short window for imaging of blood vessels as it is
diluted in blood stream and excreted rapidly.
45. BLOOD POOL AGENTS
• These agents reversibly bind to plasma albumin achieving
a substantial improvement in magnitude and duration of
blood pool enhancement.
• Eg- spio-super paramagnetic iron oxide crystals
-Uspio
-Magnetite
• These cause predominant T2 shortening.
Uses – to image small vessels(eg acc renal, cor ).
–vessels with slow flow (eg pul emb, dvt),
-Arteriovenous malformation
- Perfusion studies
• Disadv: overlap b/w arterial and venous structures and
separation is difficult
46. LIVER CONTRAST AGENTS
• Gadobenate dimeglumine (multihance,bracco)
• Small iron particles- endorem & resovist
• Manganese –containing contrast agents- teslascan –
absorbed by liver, pancreas and cortex of kidneys, T1
relaxation
47. ENDOLUMINAL CONTRAST AGENTS
• Negative contrast agents, based on iron particles(abdoscan,
nycomed-amersham) for use in MR enteroclysis & MR
imaging of rectal cancer.
• Combination of methyl cellulose solution for bowel
distention & iv gadopentate dimeglumine for bowel wall
enhancement.
• Natural contrast- blueberry juice acts as a negative
contrast in upper abdominal mr imaging, eg mrcp
48. TARGETED CONTRAST AGENTS
• BLOOD POOL AGENTS
• LIVER SPECIFIC AGENTS
• NECROSIS SPECIFIC AGENTS (BIS-GADOLINIUM-MESOPORPHYRIN)
• LYMPHOGRAPHIC CONTRAST AGENTS
• AGENTS TARGETED AT INFLAMMATION DETECTION.
54. PHARMACOKINETICS
• The pharmacokinetics of all extracellular MRI contrast agents with the
exception of gd-bopta are similar to iodinated water-soluble contrast
media.
• After iv injection they are rapidly diffused into the interstitial extravascular
space.
• Gd chelates are eliminated unchanged from the intravascular compartment
by passive glomerular filtration.
• By 24 hours >95 per cent of the injected dose is excreted in urine with
normal renal function.
• A very small amount (<0.1 per cent) is eliminated via faeces. The biological
half-life is approximately 1.5h.
• Extracellular mri contrast agents do not cross the intact specialized
vascular blood–brain barrier .
55. CLINICAL USE OF EXTRACELLULAR MRI CONTRAST AGENTS
• These agents accumulate in tissues with abnormal vascularity
(malignant, infective and inflammatory lesions) and in regions where the
blood–brain barrier is disrupted.
• Dosage
• 0.1 millimol/kg or 0.2 ml/kg
• Max dose – 20 ml
• Lethal dose– 10 mmol/kg
56. SAFETY OF EXTRACELLULAR MRI CONTRAST
AGENTS
• Extracellular MRI contrast agents are well tolerated with a low
incidence of adverse effects.
• In blood, the osmotic load of all gd-based contrast media is
very low, compared to iodinated contrast media, because only
a small amount of the contrast agent is required to produce a
diagnostic mri examination.
57. • Side effects
• Minimal with standard dose.
• Slight transitory increase in bilirubin & blood iron.
• Mild transitory head ache (9.8%).
• Nausea (4 %).
• Vomiting ( 2%).
• Hypotension, rash ( 1%).
• Life-threatening reactions are very rare.
58. CONTRAINDICATIONS
• No known contraindication.
• Although , caution in
• Hematological disorders- hemolytic anemia.
• Pregnancy, lactation.
• Respiratory disorders- asthma.
• Previous allergy.
59. HEPATOCYTE SPECIFIC CM
• Gadolinium based compounds:
• These agents have a capacity for weak and transient protein binding and is
eliminated through both the renal and hepatobiliary pathways.
• The hepatic uptake represents 2–4 per cent of the injected dose.
• It behaves as a conventional extracellular contrast agent in the first
minutes following iv administration and as a liver-specific agent in a later
delayed phase (40–120 min after administration) when it is taken up
specifically by normal functioning hepatocytes.
• Gadobenate dimeglumine (gd- bopta)- multihance
• Gadoxetic acid ( gd-eob-dtpa)- eovist
60. • Mangafodipir trisodium – teslascan
• Is strongly paramagnetic due to unpaired electrons.
• Mn usually toxic , but made tolerable by complexing to a molecule
which facilitates binding to plasma protein.
• Primarily excreted by liver -70% (as similar chemical structure to vit
b6).
• Also taken by tissues with active aerobic metabolism- pancreas, renal
cortex, gi mucosa, myocardium, adrenals.
• So far approved by fda only for diagnosing liver lesions.
• Acts by shortening t1 relaxation time.
61. RETICULO ENDOTHELIAL CELL SPECIFIC
• FERUMOXIDES –
• ARE SPIO ( POLYSACCHARIDE COATED SUPER PARAMAGNETIC
IRON OXIDE) PARTICLES.
• CONTAIN A CENTRAL CORE OF IRON OXIDE PARTICLE
SURROUNDED BY A THIN INCOMPLETE DEXTRAN COATING,
THAT CAUSES INDIVIDUAL PARTICLES TO FORM
POLYCRYSTALLINE AGGREGATES.
• THEY HAVE A SIZE OF APPROX 50- 200 NM.
62. • RES IN LIVER, SPLEEN, BONE MARROW TAKE UP THE AGENT & HAS A
LOW SIGNAL IN TI OR T2*.
• LESIONS NOT CONTAINING RECELLS DO NOT TAKE UP THE AGENT &
REMAIN UNAFFECTED, SO HAVE A HIGH SIGNAL.
• IMMEDIATELY FOLLOWING IV ADMINISTRATION, THE CONTRAST AGENT
ALSO CAUSES T1 RELAXATION AND EARLY T1-WEIGHTED IMAGING MAY
BE PERFORMED.
• USES
• DIFFERENTIATE B/W HEPATIC ORIGIN TUMOR THAT CONTAIN RES &
TUMORS THAT DO NOT.
63. • DOSE
• IV SLOW INFUSION OVER 30 MIN.
• 0.56 MG OF IRON ( 0.05 ML FERIDEX) /KG.
• SHOULD BE DILUTED IN 100 ML OF 50% DEXTRAN.
• FURTHER DELAY OF 30 MIN PRIOR TO IMAGING ALLOW FOR MAXIMUM
UPTAKE BY RE CELLS.
• CONTRAST ENHANCEMENT OBSERVED FROM 30 MIN TO 4 HRS
FOLLOWING INFUSION.
64. • SIDE EFFECTS
• HAS A GOOSAFETY PROFILE.
• BUT IN <3 % PTS- LOW BACK ACHE DURING INFUSION, USUALLY SELF
LIMITING, DISAPPEAR AFTER STOPPING/ SLOWING, ALSO LEG, GROIN
PAIN, HEAD, NECK PAIN.
• RARELY -GI- NAUSEA, VOMITING, DIARRHEA, ANAPHYLAXIS,
HYPOTENSION.
• C/I - PTS WITH ALLERGY, HYPERSENSITIVE TO IRON, PARENTERAL
DEXTRAND.
65. BLOOD POOL AGENTS
• These agents reversibly bind to plasma albumin achieving a substantial
improvement in magnitude and duration of blood pool enhancement.
• Circulate in intravascular space for a longer time, cause significant
reduction in t1 relaxation time of circulating blood.
• So best for mra.
• Eg- spio-super paramagnetic iron oxide crystals
-Uspio
-Magnetite
• These cause predominant T2 shortening.
• Uses - to image small vessels(eg acc renal, cor ).
- vessels with slow flow (eg pul emb, dvt),
- Arteriovenous malformation
- Perfusion studies
• Disadv: overlap b/w arterial and venous structures and separation is
difficult
• Gadofosveset (ms-325)
66. OTHER TISSUE SPECIFIC MR CONTRAST MEDIA
• ATHEROSCLEROTIC PLAQUES (ASP)
• USPIO S ACCUMULATE IN MONOCYTE -MACROPHAGES OF ASP.
• GADOFLUORINES ACCUMULATE IN FOAM CELLS & CELLULAR DEBRIS
DEEP TO INTIMA AT SITES OF ASP.
• NECROSIS- GADOPHORINS –USED TO ASSESS MYOCARDIAL NECROSIS.
• TUMOR SPECIFIC MR CM -
• EG: MONOCLONAL ANTIBODY LABELED PARAMAGNETIC & SUPER
PARAMAGNETIC NANOPARTICLES.
• PERFLUORINATED GASES, GD BASED AEROSOLS , HYPERPOLARIZED HE &
O2 GAS – IMAGING LUNGS .
67. ORAL CONTRAST MEDIA
• NON SPECIFIC.
• USED IN ABDOMEN & PELVIS STUDIES TO PROVIDE RELIABLE
DIFFERENTIATION OF BOWEL FROM ADJACENT STRUCTURES & TO
PROVIDE BETTER DELINEATION OF BOWEL WALL.
• POSITIVE CM.
• NEGATIVE CM.
68. POSITIVE CONTRAST MEDIA
• INCREASE THE OVERALL SIGNAL INTENSITY WITHIN THE IMAGE, BY
SHORTENING T1 TIMES OF TISSUE WATER.
• GENERALLY SOLUTION OF PARAMAGNETIC METAL IONS.
• MOSTLY PRESENT IN NATURAL PRODUCTS ( MN IN TEA).
• SPECIFICALLY FORMULATED AGENTS-
• MN CHLORIDE ( LUMENHANCE)- T1 RELAXING
• GD DTPA (MAGNEVIST ENTERAL)- ,,
BUT THE INCREASED SIGNAL MAY INDUCE GREATER ARTIFACTS DUE TO
PERISTALSIS. USE OF ANTISPASMODIC AGENTS & ULTRA FAST IMAGING
TECHNIQUES CAN SOLVE THIS.
69. NEGATIVE CONTRAST MEDIA
• ELIMINATE TISSUE SIGNAL FROM THE AREA OF INTEREST BY:-
• REDUCING THE T2 RELAXATION TIME – BY USING
SUSPENSION OF FUROMOXIDE PARTICLES.
• OR BY USING AN AGENT THAT CONTAINS NO PROTONS, &
THEREFORE PRODUCE NO VISIBLE MR SIGNAL.
• BARIUM SULPHATE, USED FOR INTRA LUMINAL STUDIES.
70. CONTRAST MEDIA RELATED TO SPECIFIC CLINICAL
AREAS
• RENAL TRACT
THERE IS NO DOUBT THAT HIGH DOSES OF CONTRAST MEDIA IMPAIR
RENAL FUNCTION, USUALLY PEAKING AT 3–5D, CAUSING A DECREASE IN
URINE OUTPUT AND AN INCREASE IN SERUM CREATININE AND UREA
LEVELS, DECREASED CREATININE CLEARANCE AND REDUCED
GLOMERULAR FILTRATION RATE (GFR). IN SOME PATIENTS THIS MAY
PROCEED TO RENAL FAILURE WITH ANURIA, URAEMIA AND DEATH.
RENAL DIALYSIS (EITHER INTRAVASCULAR OR PERITONEAL) IS VERY
EFFECTIVE AND MAY BE LIFE-SAVING AS AN ALTERNATIVE METHOD OF
EXCRETING RCM AND URAEMIC METABOLIC PRODUCTS.
71. • THESE SEVERE ADVERSE REACTIONS ARE VERY UNLIKELY TO OCCUR IF THE PATIENT IS
WELL HYDRATED AND HAS NORMAL RENAL FUNCTION BEFORE THE RCM INJECTION.
PARTICULARLY IMPORTANT ADVERSE FACTORS ARE PRE-EXISTING RENAL FAILURE
AND OLIGURIA, DIABETIC NEPHROPATHY, NEPHROTOXIC DRUGS, PATIENTS WHO ARE
NOT WELL HYDRATED AND PATIENTS WHO ARE LIABLE TO BE INJECTED WITH VERY
HIGH DOSES OF RCM FOR MULTIPLE SEQUENTIAL EXAMINATIONS REPEATED WITHIN A
FEW DAYS. ALTERNATIVE IMAGING PROCEDURES MUST ALWAYS BE CONSIDERED.
72. • THE USUAL RECOMMENDED DOSE FOR IV UROGRAPHY IN THE NORMALLY WELL-
HYDRATED ADULT WITH NORMAL RENAL FUNCTION IS 15–25 G IODINE; THIS DOSE
MAY BE INCREASED PROVIDED THE PATIENTS ARE WELL HYDRATED (BY IV NORMAL
SALINE IF NECESSARY BEFORE, DURING AND AFTER RCM INJECTION). A MAXIMUM
OF ABOUT 70 G OF IODINE (1 G IODINE KG-1 BODY WEIGHT IN ADULTS) IS
GENERALLY ADVISABLE EVEN IN PATIENTS WITH GOOD RENAL FUNCTION, BUT
CONSIDERABLY LARGER QUANTITIES (UP TO 200 G OR EVEN 300 G OF IODINE, I.E.
UP TO 600 G OF RCM) MAY BE REQUIRED, PARTICULARLY IN DIFFICULT
ANGIOGRAPHIC AND INTERVENTIONAL PROCEDURES.
73. • AFTER EARLY UNCERTAINTY, IT IS NOW ESTABLISHED THAT HOCMS ARE MORE
NEPHROTOXIC, AND LOCMS ARE PREFERRED FOR ALL PATIENTS CONSIDERED TO
BE AT INCREASED RISK, ESPECIALLY WITH DIABETIC NEPHROPATHY. THERE IS
INCREASING EVIDENCE THAT RCM (PARTICULARLY HOCM AND LARGE DOSES)
MAY INDUCE DAMAGE TO THE TUBULES IN THE RENAL MEDULLA AND REDUCE
INTRA-MEDULLARY BLOOD FLOW IN PATIENTS WITH ACUTE CALCULUS RENAL
COLIC.
74. NERVOUS SYSTEM
• LOCMS ARE MUCH MORE COMFORTABLE FOR CEREBRAL ARTERIOGRAPHY IN THE
CONSCIOUS PATIENT AND ARE ALWAYS PREFERRED. CEREBRAL RCM PHOTOGRAPHIC
ARTERIOGRAPHY IS BEING STRONGLY CHALLENGED AND PARTIALLY DISPLACED BY CT
AND MR ANGIOGRAPHY (MRA).
CEREBRAL ANGIOGRAPHY
• ADVERSE REACTIONS TO RCM INCLUDE DILATATION OF THE EXTERNAL CAROTID
ARTERIAL TERRITORY CAUSING FACIAL PAIN AND HEAT. DAMAGE TO THE BLOOD–BRAIN
BARRIER MAY CAUSE DANGEROUS CEREBRAL OEDEMA, BRADYCARDIA AND
HYPOTENSION.
75. CARDIOVASCULAR SYSTEM
• PERIPHERAL ARTERIOGRAPHY
THE USUAL IODINE CONCENTRATION REQUIRED FOR
CONVENTIONAL FILM-SCREEN ANGIOGRAPHY IS ABOUT 300 MG
I ML-1 CONTRAST MEDIUM. CONVENTIONAL HOCM (1500
MOSMOL KG-1 WATER) HAS BEEN COMPLETELY DISPLACED FOR
PERIPHERAL ARTERIOGRAPHY BY LOCM (600–700 MOSMOL KG-1
WATER), BECAUSE THE LATTER CAUSES MUCH LESS WARMTH,
DISCOMFORT, PAIN AND MOVEMENT. LOCM PERMITS ALMOST
PAINLESS ANGIOGRAPHY IN ALL TERRITORIES, USUALLY
ELIMINATING DISCOMFORT, MOVEMENT AND THE NEED FOR
76. PERIPHERAL VENOGRAPHY
• VENOGRAPHY OF THE LEG FOR POSSIBLE DEEP VEIN THROMBOSIS
(DVT) IS THE MOST FREQUENT VENOGRAPHIC STUDY. THE
PROCEDURE IS PERFORMED BY INJECTING RCM INTO A SMALL VEIN OF
THE FOOT, WITH THE LEG DEPENDENT AND TOURNIQUETS
RESTRICTING PERIPHERAL VENOUS RETURN. IF THE DEEP VEINS ARE
ALREADY COMPROMISED AND PARTLY THROMBOSED, PERIPHERAL
VENOGRAPHY OF THE LEG IS A POTENTIALLY DANGEROUS
PROCEDURE, AS BOTH DEEP AND SUPERFICIAL VENOUS RETURN FROM
THE LEG ARE COMPROMISED, AND SOME CASES OF VENOUS
GANGRENE DUE TO VENOUS ENDOTHELIAL DAMAGE AND
THROMBOSIS HAVE BEEN INDUCED BY ATTEMPTED VENOGRAPHY.
77. • LOCM IS STRONGLY ADVISED BECAUSE OF ITS LOWER OSMOLALITY
AND ITS LESS IRRITANT EFFECT ON THE VENOUS ENDOTHELIUM.
ENDOTHELIAL CONTACT TIME SHOULD BE REDUCED TO THE MINIMUM
BY WASHING OUT WITH SALINE, MASSAGING AND EXERCISING THE LEG
IMMEDIATELY AFTER SATISFACTORY RADIOGRAPHS HAVE BEEN
OBTAINED. TERMINATION OF THE INJECTION OF CONTRAST MEDIUM
MUST BE SERIOUSLY CONSIDERED IF THE INJECTION CAUSES PAIN OR IF
THE DEEP VEINS ARE SEEN TO BE EXTENSIVELY THROMBOSED, FOR ALL
RCM MAY INDUCE THROMBOPHLEBITIS.
78. CARDIAC AND CORONARY ANGIOGRAPHY
• INTRACARDIAC INJECTIONS LOCM INJECTIONS ARE MUCH
PREFERRED AS THEY CAUSE LESS DISTURBANCE OF CARDIAC
FUNCTION, DEPRESSION OF MYOCARDIAL CONTRACTILITY,
PERIPHERAL VASODILATATION, HYPERVOLAEMIA, SYSTEMIC
HYPOTENSION AND ECG CHANGES. THEY ARE ALSO MUCH
BETTER TOLERATED SUBJECTIVELY THAN HOCM.
• PULMONARY ANGIOGRAPHY LOCM INJECTIONS SHOULD BE USED
FOR PULMONARY ANGIOGRAPHY AS THEY CAUSE LESS
ELEVATION OF THE PULMONARY ARTERY PRESSURE, COUGHING,
MOVEMENT AND DISCOMFORT. SEPARATE UNILATERAL
PULMONARY ARTERY INJECTIONS SHOULD REPLACE MAIN STEM
PULMONARY ARTERY INJECTION.
79. • AORTOGRAPHY INJECTIONS OF LOCM AT THE 300–400 MG ML-1 IODINE
CONCENTRATION ARE GREATLY PREFERRED AS THEY CAUSE MUCH LESS
DISCOMFORT AND VASODILATATION.
• CORONARY ANGIOGRAPHY HOCMS (E.G. UROGRAFIN 76 PER CENT) WITH
PHYSIOLOGICAL LEVELS OF SODIUM AND WHICH DO NOT BIND AVIDLY TO SERUM
CALCIUM (RELATED TO BUFFER AGENTS) HAD A GOOD REPUTATION FOR SELECTIVE
CORONARY ANGIOGRAPHY, BUT LOCMS ARE EVEN SAFER FOR THEY CAUSE LESS
MARKED HAEMODYNAMIC, MYOCARDIAL AND PHYSIOLOGICAL CHANGES AND
DEPRESSION