This document provides guidance on optimizing CT scan protocols for evaluating acute abdomen. It defines acute abdomen and lists common causes such as appendicitis, cholecystitis, and bowel obstruction. The document recommends CT as the best first-line imaging modality for evaluating upper right quadrant and pelvic pain. It provides details on oral, IV, and rectal contrast administration as well as scanning parameters and protocols for common acute abdomen conditions to optimize diagnostic image quality while minimizing radiation dose.
Dual energy CT utilizes two different x-ray spectra to characterize tissues. It can help address challenges with single energy CT like lesion detection and image noise. Dual energy CT works by analyzing how materials attenuate x-rays differently at various energies, allowing differentiation of substances like iodine and calcium. There are several technical approaches to dual energy CT, including sequential acquisition with two scans, rapid voltage switching between two voltages, and dual-source CT with two tube-detector pairs. Post-processing involves material decomposition and differentiation using image-domain or projection-domain algorithms.
Perfusion MRI (DSC and DCE perfusion techniques) for radiology residentsRiham Dessouky
This document provides an overview of perfusion weighted MR imaging techniques. It discusses three main types: dynamic susceptibility contrast (DSC) MR perfusion, dynamic contrast enhanced (DCE) MR perfusion, and arterial spin labeling (ASL) MR perfusion. DSC relies on signal loss from gadolinium contrast to measure parameters like relative cerebral blood volume (rCBV) and flow (rCBF). DCE uses T1 shortening effects of contrast to calculate permeability and perfusion. Both techniques are used to evaluate brain tumors and strokes by analyzing signal intensity curves. DCE is also used in breast MRI to classify enhancement curves and measure permeability with the Ktrans parameter.
Tissue harmonic imaging is an ultrasound technique that provides higher quality images compared to conventional ultrasound by collecting harmonic signals generated in tissues and filtering out transducer-generated fundamental echo signals, resulting in clearer images with improved contrast resolution, reduced artifacts, and better visualization of deeper structures and vessels. While tissue harmonic imaging improves image quality in many clinical applications, it can decrease axial resolution compared to fundamental frequency imaging due to the narrowed signal bandwidth.
Doppler ultrasound utilizes the Doppler effect to detect moving objects like blood flow inside the body. It works by transmitting ultrasound pulses into the body and detecting the change in frequency (Doppler shift) of echoes reflected from moving structures like blood cells. There are different Doppler ultrasound modes - continuous wave measures presence and direction of flow while pulsed wave provides depth information. Spectral Doppler displays flow information as a waveform while color Doppler images flow in color overlaid on anatomy. Optimization involves adjusting settings like Doppler angle, sample volume size, and velocity scale to improve sensitivity and accuracy.
This document discusses malignant liver lesions. It describes the different types of primary and secondary malignant tumors that can occur in the liver. The most common are metastatic deposits from other primary cancers, and hepatocellular carcinoma (HCC). HCC is described in detail, including risk factors, pathogenesis, imaging appearance on ultrasound, CT and MRI, staging systems, treatment surveillance, and diagnostic criteria. Other liver cancers such as cholangiocarcinoma are also briefly mentioned.
Ultrasonography is the most valuable imaging modality for evaluating the thyroid gland. It is a simple, non-invasive exam that allows visualization of the thyroid anatomy and assessment of focal lesions. Normal thyroid gland appears homogeneous and mildly hypoechoic relative to surrounding tissues, with few small blood vessels visible on Doppler. Common benign thyroid findings include nodules, colloid cysts, and inflammatory nodules from chronic thyroiditis. Malignant nodules tend to have irregular margins, microcalcifications, and increased vascularity but appearance alone is not definitive.
Breast ultrasound uses high-frequency sound waves to map the internal structures of the breast. Though it should not be used alone for screening, ultrasound can detect cancers not seen on mammography when used together with mammography. With new transducers, ultrasound can also detect malignancy associated with clustered microcalcifications seen on mammograms. Ultrasound provides high quality images of the normal and abnormal breast and can help differentiate between cystic and solid lesions.
presentation on ultrasound elastography-introduction ,techniques,physics,application, interpretation and future prospects.sourced from multiple articles.
Dual energy CT utilizes two different x-ray spectra to characterize tissues. It can help address challenges with single energy CT like lesion detection and image noise. Dual energy CT works by analyzing how materials attenuate x-rays differently at various energies, allowing differentiation of substances like iodine and calcium. There are several technical approaches to dual energy CT, including sequential acquisition with two scans, rapid voltage switching between two voltages, and dual-source CT with two tube-detector pairs. Post-processing involves material decomposition and differentiation using image-domain or projection-domain algorithms.
Perfusion MRI (DSC and DCE perfusion techniques) for radiology residentsRiham Dessouky
This document provides an overview of perfusion weighted MR imaging techniques. It discusses three main types: dynamic susceptibility contrast (DSC) MR perfusion, dynamic contrast enhanced (DCE) MR perfusion, and arterial spin labeling (ASL) MR perfusion. DSC relies on signal loss from gadolinium contrast to measure parameters like relative cerebral blood volume (rCBV) and flow (rCBF). DCE uses T1 shortening effects of contrast to calculate permeability and perfusion. Both techniques are used to evaluate brain tumors and strokes by analyzing signal intensity curves. DCE is also used in breast MRI to classify enhancement curves and measure permeability with the Ktrans parameter.
Tissue harmonic imaging is an ultrasound technique that provides higher quality images compared to conventional ultrasound by collecting harmonic signals generated in tissues and filtering out transducer-generated fundamental echo signals, resulting in clearer images with improved contrast resolution, reduced artifacts, and better visualization of deeper structures and vessels. While tissue harmonic imaging improves image quality in many clinical applications, it can decrease axial resolution compared to fundamental frequency imaging due to the narrowed signal bandwidth.
Doppler ultrasound utilizes the Doppler effect to detect moving objects like blood flow inside the body. It works by transmitting ultrasound pulses into the body and detecting the change in frequency (Doppler shift) of echoes reflected from moving structures like blood cells. There are different Doppler ultrasound modes - continuous wave measures presence and direction of flow while pulsed wave provides depth information. Spectral Doppler displays flow information as a waveform while color Doppler images flow in color overlaid on anatomy. Optimization involves adjusting settings like Doppler angle, sample volume size, and velocity scale to improve sensitivity and accuracy.
This document discusses malignant liver lesions. It describes the different types of primary and secondary malignant tumors that can occur in the liver. The most common are metastatic deposits from other primary cancers, and hepatocellular carcinoma (HCC). HCC is described in detail, including risk factors, pathogenesis, imaging appearance on ultrasound, CT and MRI, staging systems, treatment surveillance, and diagnostic criteria. Other liver cancers such as cholangiocarcinoma are also briefly mentioned.
Ultrasonography is the most valuable imaging modality for evaluating the thyroid gland. It is a simple, non-invasive exam that allows visualization of the thyroid anatomy and assessment of focal lesions. Normal thyroid gland appears homogeneous and mildly hypoechoic relative to surrounding tissues, with few small blood vessels visible on Doppler. Common benign thyroid findings include nodules, colloid cysts, and inflammatory nodules from chronic thyroiditis. Malignant nodules tend to have irregular margins, microcalcifications, and increased vascularity but appearance alone is not definitive.
Breast ultrasound uses high-frequency sound waves to map the internal structures of the breast. Though it should not be used alone for screening, ultrasound can detect cancers not seen on mammography when used together with mammography. With new transducers, ultrasound can also detect malignancy associated with clustered microcalcifications seen on mammograms. Ultrasound provides high quality images of the normal and abnormal breast and can help differentiate between cystic and solid lesions.
presentation on ultrasound elastography-introduction ,techniques,physics,application, interpretation and future prospects.sourced from multiple articles.
Triphasic CT (TPCT) Scan of the liver is essential in view of the dual blood supply of the liver. TPCT allows characterisaiton of all liver lesions and close to pathological correlaiton by non invasive imaging alone. Additionally providing segmental vascular analysis as a surgicical guide.
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 discusses renal Doppler ultrasound techniques and findings. It describes three main approaches to imaging the renal arteries - anterior, oblique, and flank. Normal and abnormal Doppler waveforms are presented. Evaluation of renal artery stenosis can be done directly by imaging the renal arteries or indirectly by imaging intrarenal arteries. Findings suggestive of stenosis include increased velocities, renal/aortic ratios over 3.5, absence of the early systolic peak, and tardus parvus waveforms. Pathologies of renal transplants like rejection, infarction, and arterial or venous stenosis are also summarized.
This presentation was held by dr. Antonio Pio Masciotra - italian radiologist - on Novembre 2012 at Prato.
It concerns about neoplastic tissue's elasticity and breast elastography.
This document discusses imaging of the pancreas. Ultrasound and CT scan are the primary modalities used. Ultrasound is useful as a screening tool due to its availability, low cost and lack of radiation. CT scan is the gold standard modality as it can accurately detect pancreatic abnormalities and complications. MRCP and MRI provide additional information and are used as problem-solving tools. The document reviews imaging features of various pancreatic pathologies such as acute pancreatitis, chronic pancreatitis, tumors and trauma.
Ultrasound elastography of breast and prostate lesionsRajesh Venunath
Ultrasound elastography is a technique that maps relative tissue stiffness. It has applications in evaluating breast and prostate lesions. Breast and prostate cancers are generally stiffer than normal tissues, appearing darker on elastograms. Ultrasound elastography can help differentiate benign from malignant lesions and improve biopsy and therapy guidance for conditions like breast fibroadenomas, cysts, invasive ductal carcinoma, and prostate cancer. It has sensitivities over 68% and specificities over 72% for detecting cancers and abnormalities.
Renal transplantation is the most desirable treatment for end-stage renal disease. Kidneys can come from cadaveric or living donors. A successful transplant depends on careful recipient and donor selection and evaluation, immunosuppression, HLA matching, and the transplant team's skills. Most recipients survive the first year, though long-term function beyond 10 years is less common. Complications include acute tubular necrosis, acute rejection, vascular issues like thrombosis or stenosis, urinary leaks, and increased cancer risk due to immunosuppression. Imaging plays a key role in evaluating donors and recipients and detecting post-transplant complications.
1. MRI is the preferred imaging modality for local staging of rectal cancer, allowing assessment of tumor stage, depth of invasion, and relationship to surrounding structures.
2. A high-quality MRI with thin slices and a small field of view is needed to accurately evaluate the tumor, lymph nodes, and circumferential resection margin.
3. Key findings on MRI include tumor distance to the mesorectal fascia, involvement of surrounding organs, and presence of extramural vascular invasion, which have prognostic significance.
This document provides information on imaging of the carotid arteries and carotid angiography. It discusses various imaging modalities used to image the carotid arteries including ultrasound, CT, MRI, CT angiography, MR angiography, duplex ultrasound, and plain films. It then provides detailed information on carotid angiography including definitions, indications, complications, techniques, and how to avoid complications. Transcranial ultrasound in premature infants is also briefly discussed.
Magnetic Resonance Angiography and techniquesAlwineAnto
This document discusses MR angiography techniques and vascular abnormalities. It begins by outlining the major vascular systems in the human body. It then describes various vascular abnormalities like stenosis, aneurysms, and arterial venous malformations. The document goes on to explain different MR angiography pulse sequences like TOF, CE MRA, and PC MRI. It provides details on TOF MRA principles and advantages/disadvantages. Common artifacts seen on TOF MRA like shine-through and susceptibility artifacts are also outlined. Finally, the document discusses CE MRA techniques including test bolus timing and advantages/disadvantages compared to TOF MRA.
RADIOLOGIC ANATOMY OF SMALL INTESTINE AND INTRODUCTION TO SMALL BOWEL OBSTRUC...Mohammad Naufal
1) The document provides an overview of the radiologic anatomy of the small intestine and introduces small bowel obstruction.
2) Key details include the anatomy and relations of the duodenum, jejunum, and ileum. Valvulae conniventes are described.
3) Small bowel obstruction is a common condition that can be evaluated using plain radiography, ultrasound, CT, or CT enterography. Findings suggestive of obstruction include dilated bowel loops and air-fluid levels.
This document discusses the Doppler ultrasound assessment of the portal venous system. It begins with an overview of the sonographic and Doppler evaluation of the portal system's anatomy and normal circulation. It then covers the assessment of specific vessels like the portal vein, hepatic veins, and hepatic artery through grayscale ultrasound and Doppler evaluation. Key aspects like normal vessel diameters, waveforms, and flow direction are defined. The document concludes by outlining the important Doppler assessment techniques and parameters used to evaluate the portal system.
This document provides information on renal artery anatomy and Doppler ultrasound evaluation of the renal arteries. It describes:
1. The typical origin and course of the right and left renal arteries. Approximately 30% of individuals have variant anatomy with more than one renal artery on each side.
2. How Doppler ultrasound is used to image the renal arteries from different approaches and measure parameters like peak systolic velocity to evaluate for renal artery stenosis.
3. The normal Doppler waveforms expected in the main renal artery and intrarenal arteries, as well as normal values for measured parameters.
4. How a bilateral renal Doppler examination is performed, including evaluating each kidney, the renal arteries and veins, and measuring parameters to identify
This document discusses mediastinal masses, beginning with an overview of the mediastinum and its divisions. It then focuses on anterior mediastinal masses, describing various pathologies that can occur including thymoma, thymolipoma, thymic hyperplasia, and thymic cysts. For each pathology, it discusses incidence, associations, pathology, and radiographic features visible on plain radiographs and CT scans. Key signs on imaging include mass location and characteristics, presence of cystic or fatty components, calcification, and effects on surrounding structures.
Magnetic Resonance Angiography and VenographyAnjan Dangal
Introduction to MR Angiography and Venography Procedure of Brain . Includes Indication, MRI protocol, planning and anatomy as well as brief intoduction to physics behind MRA and MRV principle.
This document discusses various techniques for reducing radiation dose in computed tomography (CT) scans. It outlines strategies such as using automatic exposure control, adjusting scan parameters based on patient size, employing noise-tolerant images when possible, limiting scan lengths and phases, and utilizing newer reconstruction techniques. The goal is to lower radiation dose without compromising diagnostic image quality.
The document provides detailed information about the anatomy and physiology of the brain and head. It describes the three main parts of the brain - the cerebrum, cerebellum and brain stem. It discusses the lobes of the cerebrum and various deep brain structures. The document then covers the skull, use of CT scanning to image the brain, the CT scanning procedure, common pathologies visible on brain CT scans, and provides examples of labeled brain CT images.
This document discusses the use of CT imaging in evaluating acute abdominal pain. It outlines common causes of acute abdomen including gastrointestinal issues like appendicitis, diverticulitis, bowel obstruction, and perforation. It also mentions genitourinary causes and hepatobiliary and vascular etiologies. The document reviews the CT protocol and imaging appearances of various acute abdominal pathologies like appendicitis, diverticulitis, small bowel obstruction, pancreatitis, aortic aneurysm and dissection. It emphasizes that CT allows for a rapid and cost-effective evaluation of the acute abdomen when performed with the proper technique and protocol.
Triphasic CT (TPCT) Scan of the liver is essential in view of the dual blood supply of the liver. TPCT allows characterisaiton of all liver lesions and close to pathological correlaiton by non invasive imaging alone. Additionally providing segmental vascular analysis as a surgicical guide.
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 discusses renal Doppler ultrasound techniques and findings. It describes three main approaches to imaging the renal arteries - anterior, oblique, and flank. Normal and abnormal Doppler waveforms are presented. Evaluation of renal artery stenosis can be done directly by imaging the renal arteries or indirectly by imaging intrarenal arteries. Findings suggestive of stenosis include increased velocities, renal/aortic ratios over 3.5, absence of the early systolic peak, and tardus parvus waveforms. Pathologies of renal transplants like rejection, infarction, and arterial or venous stenosis are also summarized.
This presentation was held by dr. Antonio Pio Masciotra - italian radiologist - on Novembre 2012 at Prato.
It concerns about neoplastic tissue's elasticity and breast elastography.
This document discusses imaging of the pancreas. Ultrasound and CT scan are the primary modalities used. Ultrasound is useful as a screening tool due to its availability, low cost and lack of radiation. CT scan is the gold standard modality as it can accurately detect pancreatic abnormalities and complications. MRCP and MRI provide additional information and are used as problem-solving tools. The document reviews imaging features of various pancreatic pathologies such as acute pancreatitis, chronic pancreatitis, tumors and trauma.
Ultrasound elastography of breast and prostate lesionsRajesh Venunath
Ultrasound elastography is a technique that maps relative tissue stiffness. It has applications in evaluating breast and prostate lesions. Breast and prostate cancers are generally stiffer than normal tissues, appearing darker on elastograms. Ultrasound elastography can help differentiate benign from malignant lesions and improve biopsy and therapy guidance for conditions like breast fibroadenomas, cysts, invasive ductal carcinoma, and prostate cancer. It has sensitivities over 68% and specificities over 72% for detecting cancers and abnormalities.
Renal transplantation is the most desirable treatment for end-stage renal disease. Kidneys can come from cadaveric or living donors. A successful transplant depends on careful recipient and donor selection and evaluation, immunosuppression, HLA matching, and the transplant team's skills. Most recipients survive the first year, though long-term function beyond 10 years is less common. Complications include acute tubular necrosis, acute rejection, vascular issues like thrombosis or stenosis, urinary leaks, and increased cancer risk due to immunosuppression. Imaging plays a key role in evaluating donors and recipients and detecting post-transplant complications.
1. MRI is the preferred imaging modality for local staging of rectal cancer, allowing assessment of tumor stage, depth of invasion, and relationship to surrounding structures.
2. A high-quality MRI with thin slices and a small field of view is needed to accurately evaluate the tumor, lymph nodes, and circumferential resection margin.
3. Key findings on MRI include tumor distance to the mesorectal fascia, involvement of surrounding organs, and presence of extramural vascular invasion, which have prognostic significance.
This document provides information on imaging of the carotid arteries and carotid angiography. It discusses various imaging modalities used to image the carotid arteries including ultrasound, CT, MRI, CT angiography, MR angiography, duplex ultrasound, and plain films. It then provides detailed information on carotid angiography including definitions, indications, complications, techniques, and how to avoid complications. Transcranial ultrasound in premature infants is also briefly discussed.
Magnetic Resonance Angiography and techniquesAlwineAnto
This document discusses MR angiography techniques and vascular abnormalities. It begins by outlining the major vascular systems in the human body. It then describes various vascular abnormalities like stenosis, aneurysms, and arterial venous malformations. The document goes on to explain different MR angiography pulse sequences like TOF, CE MRA, and PC MRI. It provides details on TOF MRA principles and advantages/disadvantages. Common artifacts seen on TOF MRA like shine-through and susceptibility artifacts are also outlined. Finally, the document discusses CE MRA techniques including test bolus timing and advantages/disadvantages compared to TOF MRA.
RADIOLOGIC ANATOMY OF SMALL INTESTINE AND INTRODUCTION TO SMALL BOWEL OBSTRUC...Mohammad Naufal
1) The document provides an overview of the radiologic anatomy of the small intestine and introduces small bowel obstruction.
2) Key details include the anatomy and relations of the duodenum, jejunum, and ileum. Valvulae conniventes are described.
3) Small bowel obstruction is a common condition that can be evaluated using plain radiography, ultrasound, CT, or CT enterography. Findings suggestive of obstruction include dilated bowel loops and air-fluid levels.
This document discusses the Doppler ultrasound assessment of the portal venous system. It begins with an overview of the sonographic and Doppler evaluation of the portal system's anatomy and normal circulation. It then covers the assessment of specific vessels like the portal vein, hepatic veins, and hepatic artery through grayscale ultrasound and Doppler evaluation. Key aspects like normal vessel diameters, waveforms, and flow direction are defined. The document concludes by outlining the important Doppler assessment techniques and parameters used to evaluate the portal system.
This document provides information on renal artery anatomy and Doppler ultrasound evaluation of the renal arteries. It describes:
1. The typical origin and course of the right and left renal arteries. Approximately 30% of individuals have variant anatomy with more than one renal artery on each side.
2. How Doppler ultrasound is used to image the renal arteries from different approaches and measure parameters like peak systolic velocity to evaluate for renal artery stenosis.
3. The normal Doppler waveforms expected in the main renal artery and intrarenal arteries, as well as normal values for measured parameters.
4. How a bilateral renal Doppler examination is performed, including evaluating each kidney, the renal arteries and veins, and measuring parameters to identify
This document discusses mediastinal masses, beginning with an overview of the mediastinum and its divisions. It then focuses on anterior mediastinal masses, describing various pathologies that can occur including thymoma, thymolipoma, thymic hyperplasia, and thymic cysts. For each pathology, it discusses incidence, associations, pathology, and radiographic features visible on plain radiographs and CT scans. Key signs on imaging include mass location and characteristics, presence of cystic or fatty components, calcification, and effects on surrounding structures.
Magnetic Resonance Angiography and VenographyAnjan Dangal
Introduction to MR Angiography and Venography Procedure of Brain . Includes Indication, MRI protocol, planning and anatomy as well as brief intoduction to physics behind MRA and MRV principle.
This document discusses various techniques for reducing radiation dose in computed tomography (CT) scans. It outlines strategies such as using automatic exposure control, adjusting scan parameters based on patient size, employing noise-tolerant images when possible, limiting scan lengths and phases, and utilizing newer reconstruction techniques. The goal is to lower radiation dose without compromising diagnostic image quality.
The document provides detailed information about the anatomy and physiology of the brain and head. It describes the three main parts of the brain - the cerebrum, cerebellum and brain stem. It discusses the lobes of the cerebrum and various deep brain structures. The document then covers the skull, use of CT scanning to image the brain, the CT scanning procedure, common pathologies visible on brain CT scans, and provides examples of labeled brain CT images.
This document discusses the use of CT imaging in evaluating acute abdominal pain. It outlines common causes of acute abdomen including gastrointestinal issues like appendicitis, diverticulitis, bowel obstruction, and perforation. It also mentions genitourinary causes and hepatobiliary and vascular etiologies. The document reviews the CT protocol and imaging appearances of various acute abdominal pathologies like appendicitis, diverticulitis, small bowel obstruction, pancreatitis, aortic aneurysm and dissection. It emphasizes that CT allows for a rapid and cost-effective evaluation of the acute abdomen when performed with the proper technique and protocol.
This document provides protocols and guidelines for various CT scans of the abdomen and pelvis. It discusses considerations for contrast administration such as nephroprotection for patients with renal insufficiency. Guidelines are provided for oral and rectal contrast administration as well as scanning techniques to reduce artifacts. Specific protocols are outlined for common exams such as routine abdomen/pelvis CT, CT urogram, and liver mass evaluation.
1) CT dose index (CTDI) measures radiation output of CT scanners. Modern measures include CTDI100, CTDIvol, and dose length product (DLP).
2) Automatic exposure control (AEC) modulates tube current based on patient attenuation to maintain consistent image quality while reducing dose.
3) Dose reduction techniques in CT include AEC, bowtie filters, iterative reconstruction, prospective gating, and dynamic collimation.
The document provides guidance on reading head CT scans for physicians. It outlines the basic principles of CT scanning, including its history and components. It then reviews normal neuroanatomy as seen on head CT scans, illustrating various anatomical structures and landmarks visible in different axial sections. The document aims to help physicians accurately interpret CT findings to diagnose and treat time-sensitive conditions without specialist assistance.
This document summarizes key findings on abdominal CT imaging. It describes the use of intravenous contrast agents to opacify vessels and enhance organ contrast. It outlines normal anatomy and measurements of abdominal organs and vessels. Common abdominal pathologies are discussed, including hernias, masses, fluid collections, vascular diseases and peritoneal abnormalities. Artifacts, window settings, and radiographic opacities are also reviewed.
This document presents 6 cases of abdominal CT scans. Case 1 shows focal nodular hyperplasia appearing as a hypo- or isodense lesion on non-contrast CT that enhances brightly on arterial phase with a central scar remaining hypodense. Case 2 shows superior mesenteric artery syndrome appearing as compression of the duodenum between the aorta and SMA on CT. Case 3 shows omental cake from ovarian cancer metastases appearing as infiltration of omental fat. Case 4 shows ulcerative colitis with colonic mass. Case 5 shows emphysematous cholecystitis in a diabetic patient appearing on CT as gas within the gallbladder wall and/or lumen. Case 6 shows mesenteric lipod
Spectral imaging and iterative reconstruction techniques are redefining the rules of clinical CT. These new techniques allow for ultra-low dose CT scans at diagnostic quality with up to 95% dose reduction compared to standard CT. They also enable artifact reduction and improved tissue characterization. Spectral imaging using dual energy CT generates multiple datasets that can be used to create material-specific images like iodine and water images, improving detection and characterization of lesions. Iterative reconstruction further reduces image noise improving low dose imaging. Together these techniques are opening new dimensions in CT imaging capabilities.
This document provides information about dose reduction techniques in CT scanning. It discusses how CT scan technology has advanced but also leads to higher radiation doses compared to other modalities. Various techniques can help reduce dose like adjusting acquisition parameters such as tube current, voltage, and scan length. Equipment designs with features like iterative reconstruction and dual-layer detectors can also help lower dose. Selecting the appropriate scan protocol tailored to the clinical task is important to optimize image quality while keeping radiation exposure as low as reasonably achievable.
The document outlines the procedures for performing an annual performance evaluation of a computer tomography (CT) scanner using an ACR CT phantom. It involves tests to evaluate positioning accuracy, CT number accuracy, slice thickness, low contrast resolution, high contrast resolution, image uniformity and noise, and distance measurement accuracy. The tests involve scanning the various modules of the ACR phantom using different protocols and recording measurements of CT numbers, slice thicknesses, smallest visible rods, uniformity, artifacts, and resolved bar patterns.
An abdominal CT scan uses x-rays to create detailed cross-sectional images of the abdomen. During the test, the patient lies still on a table that slides into a scanner, which rotates an x-ray beam around the body. Images are created as "slices" and can be combined to form 3D models. An abdominal CT scan is used to detect various abdominal abnormalities such as masses, tumors, infections, kidney stones, and issues affecting the liver, gallbladder, or pancreas. Abnormal results could indicate cancers, organ problems, appendicitis, aneurysms, or other issues requiring follow-up.
Computerized tomography (CT) was pioneered by Godfrey Hounsfield and Allan Cormack in the 1970s. CT uses X-rays and computer processing to create cross-sectional images of the body. The first CT scanners used a translate-rotate design, while later generations used multiple detectors and spiral scanning for faster, more detailed imaging. Image reconstruction uses back projection to convert attenuation measurements into pixel values and display slices. CT provides excellent anatomical detail and is widely used for diagnosing conditions of the brain, blood vessels, lungs and other organs.
Wrap or aliasing artefact occurs when anatomy outside the field of view is folded into the field of view. This is caused by under sampling data from signals originating outside the field of view during either frequency or phase encoding. Frequency wrap can be reduced by increasing sampling frequency or using a frequency filter, while phase wrap can be reduced by enlarging the field of view to avoid duplicating phase values or using anti-fold over techniques that increase the number of phase encodings. However, these methods decrease spatial resolution or increase scan time.
European guidance on estimating population doses from medical xrayAna Pires
This document provides guidance on estimating population doses from medical x-ray procedures in Europe. It discusses estimating the frequency of x-ray exams, assessing patient doses, and presenting results. The key purposes are to observe trends in collective dose over time, determine contributions by exam type, and allow international comparisons. Proper population dose estimates require accounting for the age and sex distributions of patients, as medical exposures are not uniform across populations. Regular assessments inform authorities on high exposure groups to focus radiation protection efforts.
68 year old male presents with a 3 day history of severe
right-sided abdominal pain radiating down into his right scrotum. He has had associated vomiting on 3 occasions and his wife reports that the bedsheets and pillow case were drenched with sweat last night.
On examination, his vitals are: 38.6 degrees, 130bpm, 100/60mmHg, 24 breaths/min, 97% sats on room air. His peripheries are warm and vasodilated. Chest is clear. Abdomen demonstrates localised peritonism in the right lower quadrant. Testes are non-tender.
His urine dipstick is negative for blood, leukocytes or nitrites. Labs demonstrate a white cell count 18 and CRP 280. Renal function is normal.
Blood cultures are collected which quickly grow Clostridium.
A CT Abdomen and Pelvis is performed with IV contrast. Review the scan and identify the primary pathology which explains the patient's presentation.
ANSWER:
There is a small right indirect inguinal hernia containing an
enlarged 9.5mm inflamed appendix with associated fat stranding and minimal fluid. This finding of acute appendicitis contained within an inguinal hernia is consistent with Amyand's hernia. There are no features of small or large bowel obstruction. There is no free fluid or gas within the abdomen. There is no definite intraabdominal lymphadenopathy.
Incidentally, there are numerous other findings in this scan, including cholelithiasis without features of cholecystitis; multiple simple liver cysts; bilateral renal cortical cysts; a large hiatal hernia; a 12mm short-axis elongated lesion in the right para-aortic region posterior to the crus of the diaphragm, which may represent a lymph node. Additionally, there is subcutaneous emphysema involving the lower abdominal wall.
Amyand's hernia is a rare form of inguinal hernia in which the vermiform appendix becomes incarcerated within the hernia. Its incidence is less than 1%. The condition is named after Claudius Amyand, an English surgeon, who is attributed with performing the first successful appendicectomy on a young boy who had appendicitis contained within an inguinal hernia.
The document describes the development of an ASIC for spectral counting and imaging of x-rays. The ASIC has been designed for readout of cadmium telluride radiation sensors with up to 64 pixels. Each channel contains components to perform charge measurement and discrimination. Prototypes using the ASIC have been tested for applications such as material separation using dual-energy imaging and micro-computed tomography. The presentation discusses the ASIC design specifications and requirements for spectral photon counting in applications including industrial scanning and medical imaging.
Overview of Integrated Detector Electronics products including Application Specific Integrated Circuits, ROICs and low noise amplifiers for radiation detection.
nuclear medicine in functional disorder of gastrointestinal tract, hepatobiliary system and pancreatic lesions, inflammatory bowel disease, carcinoma of colon, esophageal carcinoma, gist , carcinoid
This document provides details on the technique of CT enterography for evaluating diseases of the small bowel. It discusses the history and advantages of CT enterography over other imaging methods. It describes the optimal protocol for CT enterography, including the use of oral contrast agents to distend the bowel as well as intravenous contrast. It also discusses variations such as multiphase scanning and methods for reducing radiation dose. Additional imaging techniques for evaluating the small bowel like MRI enterography are also summarized.
1) Abdominal trauma is a major public health problem worldwide, with blunt trauma making up around 2/3 of cases and road traffic accidents being the most common cause.
2) A thorough history and physical exam are important to evaluate abdominal trauma patients, but diagnostic modalities like FAST ultrasound, CT scan, and DPL may be needed depending on stability.
3) For stable blunt trauma patients, non-operative management is preferred when possible, while unstable patients generally require exploratory laparotomy. Penetrating trauma patients often require laparotomy depending on injury characteristics.
Carcinoma of the stomach is usually suspected based on symptoms like abdominal pain or indigestion. Investigations include endoscopy with biopsy, which is the gold standard for diagnosis. Staging involves endoscopic ultrasound, CT, PET scans and laparoscopy. Treatment depends on the stage, and may involve surgery such as gastrectomy with lymph node dissection, adjuvant chemotherapy and/or radiotherapy. Prognosis depends on factors like stage, lymph node involvement and response to treatment, with 5-year survival rates ranging from 95% for early stage to near 0% for metastatic disease.
This document provides an overview of anal cancer management. It discusses the epidemiology, risk factors, pathology, spread, clinical presentation, staging, treatment including role of surgery and radiotherapy, toxicities, indications for postoperative radiotherapy, palliative care, relapse, and special circumstances like HIV patients. Radiotherapy techniques including delineation of target volumes and organs at risk are described in detail. The document is a comprehensive reference for clinicians on anal cancer management.
Radiotherapy in Early stage invasive breast carcinomaastha17srivastava
This document discusses radiotherapy treatment for early stage invasive breast carcinoma. It provides details on diagnostic workup, treatment options including mastectomy and breast conserving therapy. It describes different types of mastectomies and details on breast conserving therapy including whole breast radiotherapy and tumor bed boost. It summarizes key studies showing no overall survival advantage of mastectomy over breast conserving therapy with radiotherapy and the benefit of tumor bed boost in reducing local recurrence. It also discusses techniques for delivering radiotherapy to different treatment volumes.
CE Title: Gastrointestinal Bleeding Scintigraphy: Changing the Paradigm
Presented at the Annual Meeting of the Society of Nuclear Medicine and Molecular Imaging, held in Denver, CO on Tuesday, June 13, 2017, 8:00 AM–9:30 AM
Educational Objectives
Upon completion of this activity, the participant will be able to:
1. Interpret GIBS images, planar and SPECT/CT.
2. Compare GIBS with available diagnostic tests used in GI bleeding, including GIB-CTA, endoscopy, etc.
3. Implement the best practice technique for GIBS, based on the revised SNMMI guideline document.
This document discusses the stage-wise treatment of urinary bladder cancer. It begins by outlining the aims of managing superficial, muscle-invasive, and metastatic bladder cancers. For superficial cancers, it describes risk stratification, treatment options including transurethral resection and intravesical therapies like BCG, and their toxicities. For muscle-invasive cancers, it discusses modalities like radical cystectomy, lymphadenectomy, and bladder preservation approaches including radiotherapy and chemoradiotherapy. It provides details on radiotherapy techniques, dose fractionation schedules, and ideal candidates for definitive radiotherapy versus cystectomy.
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Optimization of ct scan protocol in acute abdomen 2003 revised aa
1. Optimization Of CT Scan Protocol In
Acute Abdomen
(
Dr Hisham Al Khatib
Consultant Radiologist
Prince Sultan Military Medical City
2. Objectives
• Learn definition & causes of acute abdomen.
• Learn CT scan protocol for acute abdomen
• Learn typical CT scan findings in common
conditions of AA
3. Acute Abdomen
Any clinical condition characterized by severe
abdominal pain that develops over period of
hours ,+l- abdominal tenderness or rigidity
urgent therapeutic decision
4. Acute Abdomen
• Often difficult to diagnose
• Clinical presentation, physical examination can
be very nonspecific
• Laboratory exams: non‐diagnostic or not
specific
6. Acute Abdomen
Diagnostic work up
Abdominal plain film Ultrasound
CT MRI
Which is the best choice?
7. Acute Abdomen
Diagnostic work up
Which is the first line imaging
modality used for the upper right
quadrant and pelvic pain?
1) CT
2) US
3) MRI
4) Abdominal plain film
11. Scan Protocols
• core of every CT examination.
• protocols should be appropriate for the
clinical indication
• should include all aspects of the exam such
• positioning,
• nursing instructions,
• scan parameters( including radiation dose)
• reconstruction/reformatting instructions,
12. How do you design a CT protocol
• components
– Scanning parameters
– What do to the patient
• eg contrast when , how , and how we doing
– Dose information
– filming
– network instruction
– billing code
13. Scanning parameters
• CT machine
• kVp
• mAs
• Slice collimation
• Slice thickness
• Interscan spacing
• Reconstruction algorithm for different tissues
14. Scanning parameters
• multislice CT is better than single slice
• MSCT :
– High quality
– Wider range of examination
– Thinner slices
– Shorter scan time
– Multiphases protocol
– Better reconstruction ( isotropic voxel)
15.
16. kVp
• Between 80-140
• Higher kVp: in routine CT abdomen
• Lower KVp: CTA, perfusion studies
• Manual versus automatic KVp selection:
– Care kV, Siemens machine
17. Tube current
• mAs selected should result in diagnostic
quality images
• Most body CT and even head CT: Use AEC
18. Tube current
• For all patients less than 20 years old, set the
minimum mA to 80 for all studies.
19. Collimation
• Narrow collimation and small reconstruction
intervals can help detect calculi in the biliary
system and genitourinary tract.
• Affects
– Total scan time
– Noise / Low contrast resolution
– Thinnest available recons
• Some configurations (esp. narrow collimations)
are less dose efficient (vendor-specific)
20. • Slice thickness: Acquire thins, reconstruct
thick: Less noise
• Scan coverage: scan length
• Rotation speed: Keep fastest…for most regions
to allow breath hold tech and more coverage
21. Increment
• is the distance between the reconstructed
images in the Z direction.
• When the chosen increment is smaller than
the slice thickness, the images are created
with an overlap.
22. Increment
• is useful to reduce partial volume effect, giving
you better detail of the anatomy and high
quality 2D and 3D post-processing .
• can be freely adapted from 0.1 - 10 mm.
23. CT Image suitable for diagnostic
purpose :
– Low noise
– High contrast resolution
– Sharpness of image
– Absence of artifacts
24. Pediatric protocols
• should be adjusted regarding exposure
parameters
• Protocol optimization reducing radiation dose:
– mAs according to patient size and weight
– Implementation of automatic control sysyem
27. oral contrast
Types
• Water neutral: negative contrast used in
most cases
• Water soluble positive contrast
– Ominipaque 350
– Gastrografin agent (2% – 4%)
– Diluted barium suspension (1% – 2%) e.g., EZCAT
28. oral contrast
Volume
• Upper abdomen:
– Minimum 700-1000 ml of contrast
– divided into 3 cups (approximately 250 – 300 ml)
– 1st cup,30 minutes before exam
– 2nd cup,15 minutes before exam
– 3rd cup , 5 minutes before exam
29. oral contrast
Volume
• Abdomen-Pelvis:
– Minimum 1000 ml
– divided into 4 cups
– 1st cup ,1 hour before exam
– 2nd – 4th cups every 15 minutes
– Start exam 5 minutes after the 4th cup
30. oral contrast
• Use in
– Suspected appendicitis
– Fistula
– Leakage of contrast anatomosis gastric bypass
– Perforation
• Not used in
– High intestinal obstruction
– Ureteric colic
– Intestinal bleeding
– Vascular cuases
31. Rectal contrast
• may be used in
– appendicitis
– diverticulitis
– leak or perforation
– colonography
– penetrating injury
32. IV Contrast
• opacifies abdominal vasculature and
• provides useful information regarding
enhancement of the parenchymal organs and
intestine
• 100-120 mL of iodinated contrast material
injected
• rate of 3-5 mL per second is adequate
33. IV Contrast
• is recommended in most cases.
• Exceptions:
• include evaluation of suspected ureteral colic,
retroperitoneal hge or
• contraindication to contrast
34. IV contrast
• Normal creatinine level , should be within a month
• High creatinine level , to be discuss with ordering
physician
• Look for
– renal disease , hypertension, diabetes ,malignancy
• Consider using a lower osmolar agent (Visipaque) in
patients with diabetes and renal insufficiency
•
35. Diabetics taking Metformin (glucophage)
• should be stopped for 2 days after CT &
creatinine checked prior to restarting Metformin
• If creatinine is normal (< 1.5), I.V. contrast may be
given;
• If creatinine > 1.5,do not administer I.V. contrast.
• Contact clinician &reschedule patient.
• Contact referring clinician to obtain lab values.
36. Premedication
Allergy pateints
• Oral: 50 mg p.o. of prednisone 13 h., 7 h. and 1 h.
prior to procedure and
• 50 mg p.o. of Benadryl 1 h. prior to procedure.
These patients should be accompanied to the
hospital; they should not drive after taking
Benadryl
• IV: 200mg hydrocortisone 6h and 2h prior to
procedure and 50 mg p o of Benadryl 1h prior to
procedure
37. Technical aspect of acute abdomen
CT Imaging
• IV contrast should be given at 3-5 ml/sec
• total of 100-120 mL,
• followed by saline
• Use SMART PREP or threshold tech
38.
39. IV access
CTA's :
• high rates of injection,
• a large bore IV, 18 g or larger is required
• Do not use hand/forearm veins
• Antecubital only.
40. IV access
CTA's :
• During power injections, the site must be closely
monitored during the first 15 to 20 seconds to
prevent extravasation
• Some PICC catheters are designed for use with
power injectors,
• Check the label of any catheter for maximum flow
rate and pressure.
• Adjust the settings on the power injector
accordingly.
41. Contrast extravasation
• most are small & self limited.
Ice pack and elevate for 20 mins.
If swelling/pain resolved patient can be discharged
– Advise patient to contact MD or go to E.R. if
swelling/pin worsen
• Skin sloughing is rare, can require a referral to
plastic surgeon
42. Contrast extravasation
• Compartment syndrome :
with large volumes in the forearm/hand.
– pain with extension of fingers.
– May lose pulses
– become cold/discolored.
– requires referral to plastic/orthopedic/hand
surgeon.
43. Renal Function/Creatinine levels
• Patients with pre-existing renal failure or
Diabetes Mellitus should have creatinine
levels checked when the exam is non-
emergent
• In general, a creatinine of 1.8 or less is
acceptable for non-ionic contrast use
44. Renal Function/Creatinine levels
• For Creatinine levels above 1.8 there are several
options:
– 1. Withhold contrast if indication for contrast use is
equivocal
– 2. Administer N acetylcysteine (Mucomyst)
– 3. Use a reduced dosage.
– 4. If the patient is on dialysis with no renal function,
they can be given contrast, preferably prior to dialysis.
– 5. If the patient is on dialysis with borderline function,
the nephrologist should be consulted prior to contrast
use.
45. Contrast Allergy
• Patients with prior severe/life threatening
reactions should avoid contrast if at all
possible
• For other prior reactions, pre-medicate with
oral prednisone 50mg 13 hrs,7 hrs & 1 hr prior
to injection and oral benadryl 50 mg 1 hr prior
46. GeneralHints
• Topogram : AP, 512 or 768 mm.
• Patient positioning: Patient lying in supine
position, arms positioned comfortably above
the head in the head-arm rest lower legs
supported.
• Patient respiratory instructions: inspiration
• Scout : AP and lateral
47. GeneralHints
• Limit scan to intended anatomic area to cut
dose by 10%
– Abdomen:
• Just above diaphragm – Inferior pubic symphysis
– Chest:
• Routine: Apex to adrenals
• PE or benign clinical reasons: Apex to lung bases
50. Appendicitis
• most common causes of acute abdominal pain
• Most :1000 cc oral contrast before about 1
hour before
• Others give oral & rectal
• Scanning after 70 second from IV injection ,
might need delayed scan
51. Inflamed appendix Normal appendix
The appendix (arrows) is fluid-
filled and distended with
periappendiceal fat-stranding.
52. Acute Pyelonephritis
• Fever, chills, and flank tenderness.
• referred for CT when symptoms are poorly
localized or suspected complications .
• nephrographic phase (70–90 seconds after
injection) or
• excretory phase (5 minutes after injection).
54. Ureteral Stones
• continuous breath-hold acquisition from
kidneys to bladder base.
• Narrow (3-mm) collimation and small
reconstruction intervals (also 3 mm) are
essential for optimal detection of small calculi
• Prone scans may be needed to differentiate a
ureterovesical junction stone from a recently
passed stone
55. 51-year-old woman
obstructing calculus in the midureter
right hydronephrosis
56. Acute Pancreatitis
• Contrast:
• Patient should drink water as the oral
contrast, OPACIFICATION AND DISTENTION
OF DUODENUM IS VERY HELPFUL
• IV contrast at 4-5mL/sec for 120 mL
57. Acute Pancreatitis
• RS=0.5, narrow collimation , thin
reconstructions, apply radiation protection
facilities in the machine ( ASIR , Care dose )
• scan entire pancreas in single breath hold for
all phases.
58. Acute Pancreatitis
• Noncontrast – Liver dome to iliac crests
• Arterial phase – Initiate scan at 25 sec. Use
“SMART PREP” Aorta (150HU) to monitor
those with poor cardiac output. Top to bottom
of liver. Ideally obtain excellent pancreatic
parenchymal arterial opacification with
minimal contrast in portal vein.
59. Acute Pancreatitis
• Portal venous phase – 80 sec delay. Scan the
entire abdomen in this acquisition (top of the
liver to sp).
• Delayed 3 minute scan through liver and
kidneys.
• Coronal and sagittal reformat of portal venous
phase
60. Diverticulitis
rectal contrast:
is highly accurate for diagnosis
Most use 400–800 mL of 3% iodinated contrast
IV contrast :
helpful in detection & characterization of
pericolonic inflammation
recommended in most patients.
62. Small Bowel Obstruction
• common cause of acute abdomen
• adhesions most common (64%–79%)
• hernia (15%–25%),
• tumor (10%–15%)
63. Small Bowel Obstruction
high-grade small bowel obstruction :
• best performed without oral contrast.
• large amounts of fluid in bowel acts as a
natural contrast agent,
• when combined with IV contrast ,allows
opacification of bowel wall & masses
64. Small Bowel Obstruction
low-grade obstruction:
• oral contrast
• improves accuracy in detection of
inflammation & abscesses
• optimize identification of a transition zone
66. Ischemic Bowel
• present with symptoms ranging from
relatively minor discomfort to acute
abdominal pain, which makes clinical
diagnosis difficult
• vascular occlusion or thrombosis, whether
from arterial or venous disease, and
hypoperfusion
67. Ischemic Bowel
• rapid (4-5 mL/sec) IV contrast for optimal vascular
opacificationi
• IV contrast is essential for depiction of the
thickened, edematous bowel wall, which can
easily be appreciated against the obstructed,
fluid-filled intestine
• Arterial & venous phases are essential
• Water can be used as alternative for bowel
lumen
68. Gastrointestinal Perforation
• If possible, oral & IV contrast should be used
• to help localize perforation & characterize
complications
• Such as peritonitis and abscess formation.
70. • rapid (4-5 mL/sec) IV bolus contrast for
optimal vascular opacification
• Narrow collimation
• high-quality 3D images
• Oral contrast material is not administered ,
can interfere with reconstruction
71. AORTIC ANEURYSM
• Study should only be performed in
hemodynamically stable patients.
• Hemodynamically unstable patients with high
degree of suspicion of aortic pathology should
go directly to OR.
• If becomes unstable in CT, a quick noncon
scan may be diagnostic.
74. AORTIC DISSECTION
• Scan method:
– RS=0.5, narrow collimation , thin reconstructions,
apply radiation protection facilities in the machine
( ASIR , Care dose )
– Non contrast – show intramural hematoma not
well seen with contrast.
• Top of arch to iliac crests
75. AORTIC DISSECTION
• Arterial: Use HiRes HD mode, SMART PREP
over aortic arch with threshold 150 HU, Apices
to SP
• Portal Venous – 80 sec delay from dome of
liver to SP to assess organ perfusion.
• Coronal and sagittal reformat of arterial phase
• Coronal and sagittal MIP of arterial phase
77. LOWER EXTREMITY RUN-OFF
• Contrast:
• IV contrast at 4-5mL/sec for 125 mL (consider
increasing to 150 for very tall patients)
78. LOWER EXTREMITY RUN-OFF
• Scanning method
– RS=0.5, narrow collimation , thin reconstructions,
apply radiation protection facilities in the machine
( ASIR , Care dose )
– Noncontrast: From diaphragmatic hiatus through
toes
– Arterial:
79. LOWER EXTREMITY RUN-OFF
• SMART PREP over knees – trigger scan at first
blush of contrast. Do not use ROI!
• From diaphragmatic hiatus through toes
• Coronal and sagittal reformat of arterial phase
• Coronal MIP of arterial phase
80. Sharing protocol files
• Once protocols are made
– Educating the CT technologists
– Saving CT protocols on individual scanners
– Ensuring protocols for head go to head section
only
– Trial run in few cases – Review of images‐
81. Sharing protocol files
• Having hard copy protocol books by body
region in all scanner suites
– Scan length
– Scan phases or passes
– Contrast injection details
• Shared drive access to protocols with in the
intranet from any internal personal computer
– Electronic copies of protocols with version date
and protocol types
82. Conclusions
• Optimize the patient preparation
• Choose the best scanning protocol for
individual patient
• Optimize the dose profile for the patient
• proper technique and protocol is essential for
optimizing the CT examination and maximizing
diagnostic accuracy