This document outlines the protocol for performing CT angiography (CTA) from the cerebral arteries to the lower limbs. It discusses indications for CTA including aneurysms, stenosis, dissections, and more. The preparation, positioning, and scanning protocols are provided for CTA of the head to lower limbs as well as the subclavian arteries. Pediatric protocols are also summarized. The document concludes with examples of CTA findings and references.
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.
Computed tomography (CT) of the head is used to assess head injuries, headaches, dizziness, and symptoms of conditions like aneurysms, bleeding, strokes, and brain tumors. It can also help evaluate the face, sinuses, and skull. CT of the head uses X-rays to generate cross-sectional images of the head and brain which provide more detailed information than regular X-rays, particularly for soft tissues and blood vessels. Common protocols for head CT include non-contrast exams for conditions like trauma or stroke, as well as contrast-enhanced exams to evaluate tumors, aneurysms, or other conditions. Precautions are taken to minimize radiation exposure, especially for children.
The document discusses computed tomography (CT) of the chest and protocols for performing chest CT scans. It provides details on how chest CT is used to examine abnormalities found on other imaging tests and help diagnose conditions causing chest symptoms. It describes the CT scanning process and equipment. Common uses of chest CT are outlined, along with lung disorders it can demonstrate and benefits compared to other imaging modalities. Specific protocols for routine chest CT, high-resolution CT, low-dose CT, airway CT, and aortic angiography CT are enumerated.
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.
CT angiography (CTA) uses computed tomography (CT) and intravenous iodinated contrast to visualize blood vessels. It can be used to assess arteries, veins, and vascular structures throughout the head and neck. Performing a CTA requires optimizing multiple factors including the injection of contrast, timing of the CT scan, and image post-processing techniques. The document provides detailed guidelines on patient preparation, equipment, techniques, and safety considerations for head and neck CTA exams.
MRI provides detailed images of the brain without exposing patients to radiation. It is useful for evaluating conditions like tumors, strokes, and multiple sclerosis. The document describes the MRI procedure for brain imaging including patient preparation, head coils, sequences, and protocols. Key sequences discussed are T1-weighted, T2-weighted, FLAIR, diffusion weighted, MR angiography, and MR venography.
This document provides an overview of skull base anatomy and imaging of skull base pathology. It begins with a description of the bones that make up the skull base and key anatomical structures like foramina and sinuses. Common pathologies are then discussed, including tumors originating from within the skull base (intra-axial) or adjacent structures outside the skull base (extra-axial). Example cases of chordoma and glomus tumor are presented with imaging findings. Finally, some hints and tips for skull base MRI interpretation are provided.
This document outlines the protocol for performing CT angiography (CTA) from the cerebral arteries to the lower limbs. It discusses indications for CTA including aneurysms, stenosis, dissections, and more. The preparation, positioning, and scanning protocols are provided for CTA of the head to lower limbs as well as the subclavian arteries. Pediatric protocols are also summarized. The document concludes with examples of CTA findings and references.
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.
Computed tomography (CT) of the head is used to assess head injuries, headaches, dizziness, and symptoms of conditions like aneurysms, bleeding, strokes, and brain tumors. It can also help evaluate the face, sinuses, and skull. CT of the head uses X-rays to generate cross-sectional images of the head and brain which provide more detailed information than regular X-rays, particularly for soft tissues and blood vessels. Common protocols for head CT include non-contrast exams for conditions like trauma or stroke, as well as contrast-enhanced exams to evaluate tumors, aneurysms, or other conditions. Precautions are taken to minimize radiation exposure, especially for children.
The document discusses computed tomography (CT) of the chest and protocols for performing chest CT scans. It provides details on how chest CT is used to examine abnormalities found on other imaging tests and help diagnose conditions causing chest symptoms. It describes the CT scanning process and equipment. Common uses of chest CT are outlined, along with lung disorders it can demonstrate and benefits compared to other imaging modalities. Specific protocols for routine chest CT, high-resolution CT, low-dose CT, airway CT, and aortic angiography CT are enumerated.
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.
CT angiography (CTA) uses computed tomography (CT) and intravenous iodinated contrast to visualize blood vessels. It can be used to assess arteries, veins, and vascular structures throughout the head and neck. Performing a CTA requires optimizing multiple factors including the injection of contrast, timing of the CT scan, and image post-processing techniques. The document provides detailed guidelines on patient preparation, equipment, techniques, and safety considerations for head and neck CTA exams.
MRI provides detailed images of the brain without exposing patients to radiation. It is useful for evaluating conditions like tumors, strokes, and multiple sclerosis. The document describes the MRI procedure for brain imaging including patient preparation, head coils, sequences, and protocols. Key sequences discussed are T1-weighted, T2-weighted, FLAIR, diffusion weighted, MR angiography, and MR venography.
This document provides an overview of skull base anatomy and imaging of skull base pathology. It begins with a description of the bones that make up the skull base and key anatomical structures like foramina and sinuses. Common pathologies are then discussed, including tumors originating from within the skull base (intra-axial) or adjacent structures outside the skull base (extra-axial). Example cases of chordoma and glomus tumor are presented with imaging findings. Finally, some hints and tips for skull base MRI interpretation are provided.
This document discusses breast MRI protocols, techniques, and the interpretation of findings. It provides details on coil and patient positioning, recommended MRI field strength, and standard breast MRI protocols. It discusses recognizing normal enhancing structures like vessels, nipples, and lymph nodes. Guidelines are presented for analyzing lesion enhancement and characterizing benign masses based on criteria like smooth margins, shape, homogeneous enhancement, fat content, T2 signal, and rim enhancement. Examples of benign findings like fibroadenomas and fat-containing lesions are also described.
CT perfusion physics and its application in NeuroimagingDr.Suhas Basavaiah
CT perfusion imaging provides functional information about tissue vascularity by measuring temporal changes in tissue attenuation following intravenous injection of iodinated contrast. It quantifies parameters like blood flow, blood volume, mean transit time. While initially developed for research, advances in multidetector CT and software allow clinical use in evaluating cerebral vasculature in acute stroke and tumor response to therapies in oncology. The technique involves rapid dynamic scanning during contrast first-pass to generate time-attenuation curves and calculate perfusion values using deconvolution or other mathematical models.
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.
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.
Portable and mobile CT scanners allow for CT imaging capabilities to be brought to the patient's location rather than transporting the patient to a fixed CT scanner. They have similar image quality to traditional fixed CT machines. Portable CT scanners are smaller, with detachable components, allowing them to be moved between rooms. They reduce transport times and staff needed for scans. Various companies have developed portable head CT scanners and full-body CT scanners for point-of-care imaging in emergency departments, operating rooms, and intensive care units to improve patient outcomes.
CT imaging of the neck provides detailed anatomical information and is useful for evaluating neck masses, lymphadenopathy, thyroid diseases and trauma. The neck is divided into triangles and spaces which radiologists use to characterize abnormalities. CT protocols involve intravenous contrast administration and thin slices through the neck. MRI is also used and has advantages over CT such as better soft tissue contrast without radiation, though CT remains superior for assessing bone.
Multi detector ct cerebral angiographyEhab Elftouh
This document discusses techniques for computed tomography (CT) angiography. It covers advances in CT technology that have improved angiography, including faster scan speeds and thinner slices. Optimal CT angiography depends on scan technique factors like protocol and contrast injection, as well as image post-processing techniques. Newer multi-detector CT machines allow covering volumes more quickly and with higher resolution. Methods like multi-planar reformation and volume rendering help visualize vascular structures from CT image data.
Basic physics of multidetector computed tomography ( CT Scan) - how ct scan works, different generations of ct, how image is generated and displayed and image artifacts related to CT Scan.
The document contains questions and answers about various topics related to CT scans. It includes definitions and explanations of ring artifacts, HRCT techniques, image reconstruction methods, CT numbers, scintillation detectors, pixels, radiation profile width in CT collimators, CT number, resolution types, mass attenuation coefficient, parallel multi-hole collimators, low dose CT scans, CT guided biopsies, and CT artifacts. The document consists of questions from several students on technical aspects of computed tomography imaging.
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.
Advances in CT technology allow for higher resolution imaging with multi-slice CT scanners. This provides benefits for visualizing complex anatomy, diseases, and evaluating vasculature non-invasively with techniques like CT angiography. Additional applications enabled by high resolution volumetric data include virtual bronchoscopy and colonoscopy which provide endoluminal views to evaluate airways and the colon with benefits over conventional scopes. While CT involves ionizing radiation, doses are addressed with new technologies and some procedures may replace more invasive options, proving new CT applications are of increasing clinical value.
MDCT Principles and Applications- Avinesh ShresthaAvinesh Shrestha
Multidetector CT (MDCT) is one of the most commonly used imaging modality in the field of Radiology. Development and advancement in MDCT has made it's application as a major component in diagnosis and treatment planning of multitude of disease across the planet. This presentation briefly describes its basic principle and it's wide variety of application in medical imaging.
MRI is the preferred imaging modality for evaluating the brain as it does not use ionizing radiation. Basic MRI sequences include T1-weighted, T2-weighted, FLAIR, and DWI images which provide anatomical and functional information. Advanced techniques such as perfusion imaging, DTI, and spectroscopy provide additional data. Contrast agents can help identify lesions and breakdown of the blood-brain barrier. Proper patient screening and positioning are important to obtain diagnostic images and ensure patient safety in the MRI scanner.
1. Magnetic resonance angiography (MRA) is a non-invasive imaging technique that uses magnetic resonance imaging to visualize blood vessels and evaluate vascular anatomy and blood flow without using ionizing radiation or iodinated contrast material.
2. There are different MRA techniques including time-of-flight MRA, phase contrast MRA, and contrast-enhanced MRA. Time-of-flight MRA relies on differences in flowing and stationary blood signal while phase contrast MRA assesses velocity and direction of flow. Contrast-enhanced MRA uses gadolinium contrast to improve vessel depiction.
3. MRA has various clinical applications for evaluating carotid and intracranial arterial stenosis, aneurysms,
This document discusses diffusion weighted imaging (DWI) and its application in evaluating brain pathologies. It provides details on how DWI works using diffusion gradients and endogenous contrast from water motion. Areas of restricted diffusion like cytotoxic edema appear brighter on DWI. DWI is highly sensitive for detecting acute ischemia within minutes. It is useful for distinguishing acute from subacute lesions based on apparent diffusion coefficient (ADC) maps. DWI also has applications in evaluating other conditions like abscesses, tumors, infections and injuries.
This document provides an overview of diffusion weighted imaging (DWI) and its clinical applications. It defines diffusion and how DWI is acquired using Stejskal-Tanner pulsed gradient spin echo sequences. Key terms like b-value and apparent diffusion coefficient are explained. Clinical uses of DWI include detecting acute strokes and differentiating lesions. Body DWI using DWIBS is also discussed. Diffusion tensor imaging is introduced as a technique for visualizing white matter tract orientation using tractography maps.
Application of dect in emergency radiology including the application in diagnosis of renal calculi, bone marrow edema, gout , abdominopelvic imaging,detection of pulmonary embolism and in cardiac imaging.
1) The document discusses various types of intracranial aneurysms including their presentation, incidence, diagnosis, and radiographic features.
2) Saccular aneurysms are the most common type and can cause subarachnoid hemorrhage from rupture. They are often detected on CT/CTA or catheter angiography.
3) Other aneurysm types discussed include fusiform, dissecting, mycotic, oncotic, and traumatic pseudoaneurysms. These have different etiologies and features on imaging.
An angiogram is an imaging test that uses x-rays and dye to map the blood vessels. A catheter is inserted into an artery and threaded to the targeted blood vessels where dye is injected to make blockages visible on x-rays. Angiograms are performed to detect blockages in arteries of the heart, brain, legs, and other organs to help diagnose and plan treatment for conditions like heart disease. While it provides detailed images of blood vessels, risks include bleeding or reaction to the dye where the catheter is inserted.
This document discusses breast MRI protocols, techniques, and the interpretation of findings. It provides details on coil and patient positioning, recommended MRI field strength, and standard breast MRI protocols. It discusses recognizing normal enhancing structures like vessels, nipples, and lymph nodes. Guidelines are presented for analyzing lesion enhancement and characterizing benign masses based on criteria like smooth margins, shape, homogeneous enhancement, fat content, T2 signal, and rim enhancement. Examples of benign findings like fibroadenomas and fat-containing lesions are also described.
CT perfusion physics and its application in NeuroimagingDr.Suhas Basavaiah
CT perfusion imaging provides functional information about tissue vascularity by measuring temporal changes in tissue attenuation following intravenous injection of iodinated contrast. It quantifies parameters like blood flow, blood volume, mean transit time. While initially developed for research, advances in multidetector CT and software allow clinical use in evaluating cerebral vasculature in acute stroke and tumor response to therapies in oncology. The technique involves rapid dynamic scanning during contrast first-pass to generate time-attenuation curves and calculate perfusion values using deconvolution or other mathematical models.
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.
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.
Portable and mobile CT scanners allow for CT imaging capabilities to be brought to the patient's location rather than transporting the patient to a fixed CT scanner. They have similar image quality to traditional fixed CT machines. Portable CT scanners are smaller, with detachable components, allowing them to be moved between rooms. They reduce transport times and staff needed for scans. Various companies have developed portable head CT scanners and full-body CT scanners for point-of-care imaging in emergency departments, operating rooms, and intensive care units to improve patient outcomes.
CT imaging of the neck provides detailed anatomical information and is useful for evaluating neck masses, lymphadenopathy, thyroid diseases and trauma. The neck is divided into triangles and spaces which radiologists use to characterize abnormalities. CT protocols involve intravenous contrast administration and thin slices through the neck. MRI is also used and has advantages over CT such as better soft tissue contrast without radiation, though CT remains superior for assessing bone.
Multi detector ct cerebral angiographyEhab Elftouh
This document discusses techniques for computed tomography (CT) angiography. It covers advances in CT technology that have improved angiography, including faster scan speeds and thinner slices. Optimal CT angiography depends on scan technique factors like protocol and contrast injection, as well as image post-processing techniques. Newer multi-detector CT machines allow covering volumes more quickly and with higher resolution. Methods like multi-planar reformation and volume rendering help visualize vascular structures from CT image data.
Basic physics of multidetector computed tomography ( CT Scan) - how ct scan works, different generations of ct, how image is generated and displayed and image artifacts related to CT Scan.
The document contains questions and answers about various topics related to CT scans. It includes definitions and explanations of ring artifacts, HRCT techniques, image reconstruction methods, CT numbers, scintillation detectors, pixels, radiation profile width in CT collimators, CT number, resolution types, mass attenuation coefficient, parallel multi-hole collimators, low dose CT scans, CT guided biopsies, and CT artifacts. The document consists of questions from several students on technical aspects of computed tomography imaging.
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.
Advances in CT technology allow for higher resolution imaging with multi-slice CT scanners. This provides benefits for visualizing complex anatomy, diseases, and evaluating vasculature non-invasively with techniques like CT angiography. Additional applications enabled by high resolution volumetric data include virtual bronchoscopy and colonoscopy which provide endoluminal views to evaluate airways and the colon with benefits over conventional scopes. While CT involves ionizing radiation, doses are addressed with new technologies and some procedures may replace more invasive options, proving new CT applications are of increasing clinical value.
MDCT Principles and Applications- Avinesh ShresthaAvinesh Shrestha
Multidetector CT (MDCT) is one of the most commonly used imaging modality in the field of Radiology. Development and advancement in MDCT has made it's application as a major component in diagnosis and treatment planning of multitude of disease across the planet. This presentation briefly describes its basic principle and it's wide variety of application in medical imaging.
MRI is the preferred imaging modality for evaluating the brain as it does not use ionizing radiation. Basic MRI sequences include T1-weighted, T2-weighted, FLAIR, and DWI images which provide anatomical and functional information. Advanced techniques such as perfusion imaging, DTI, and spectroscopy provide additional data. Contrast agents can help identify lesions and breakdown of the blood-brain barrier. Proper patient screening and positioning are important to obtain diagnostic images and ensure patient safety in the MRI scanner.
1. Magnetic resonance angiography (MRA) is a non-invasive imaging technique that uses magnetic resonance imaging to visualize blood vessels and evaluate vascular anatomy and blood flow without using ionizing radiation or iodinated contrast material.
2. There are different MRA techniques including time-of-flight MRA, phase contrast MRA, and contrast-enhanced MRA. Time-of-flight MRA relies on differences in flowing and stationary blood signal while phase contrast MRA assesses velocity and direction of flow. Contrast-enhanced MRA uses gadolinium contrast to improve vessel depiction.
3. MRA has various clinical applications for evaluating carotid and intracranial arterial stenosis, aneurysms,
This document discusses diffusion weighted imaging (DWI) and its application in evaluating brain pathologies. It provides details on how DWI works using diffusion gradients and endogenous contrast from water motion. Areas of restricted diffusion like cytotoxic edema appear brighter on DWI. DWI is highly sensitive for detecting acute ischemia within minutes. It is useful for distinguishing acute from subacute lesions based on apparent diffusion coefficient (ADC) maps. DWI also has applications in evaluating other conditions like abscesses, tumors, infections and injuries.
This document provides an overview of diffusion weighted imaging (DWI) and its clinical applications. It defines diffusion and how DWI is acquired using Stejskal-Tanner pulsed gradient spin echo sequences. Key terms like b-value and apparent diffusion coefficient are explained. Clinical uses of DWI include detecting acute strokes and differentiating lesions. Body DWI using DWIBS is also discussed. Diffusion tensor imaging is introduced as a technique for visualizing white matter tract orientation using tractography maps.
Application of dect in emergency radiology including the application in diagnosis of renal calculi, bone marrow edema, gout , abdominopelvic imaging,detection of pulmonary embolism and in cardiac imaging.
1) The document discusses various types of intracranial aneurysms including their presentation, incidence, diagnosis, and radiographic features.
2) Saccular aneurysms are the most common type and can cause subarachnoid hemorrhage from rupture. They are often detected on CT/CTA or catheter angiography.
3) Other aneurysm types discussed include fusiform, dissecting, mycotic, oncotic, and traumatic pseudoaneurysms. These have different etiologies and features on imaging.
An angiogram is an imaging test that uses x-rays and dye to map the blood vessels. A catheter is inserted into an artery and threaded to the targeted blood vessels where dye is injected to make blockages visible on x-rays. Angiograms are performed to detect blockages in arteries of the heart, brain, legs, and other organs to help diagnose and plan treatment for conditions like heart disease. While it provides detailed images of blood vessels, risks include bleeding or reaction to the dye where the catheter is inserted.
CT carotid and cerebral angiography is used to study the neck arteries (carotid arteries) and brain arteries (cerebral arteries) using a CT scanner. It can detect aneurysms, narrowing of arteries in the brain, abnormal blood vessels, stenosis, and narrowing or blockage of the carotid arteries. The procedure involves inserting a cannula if needed, obtaining plain CT images of the neck and brain, injecting contrast dye using a pressure injector, and obtaining images of the arteries. It can help determine the risk of future strokes and identify issues like strictures of the carotid arteries.
The document discusses cerebral arteriography, which is a medical imaging technique used to examine the arteries in the brain and neck. Cerebral arteriography can be used to detect abnormalities, blockages, tumors, or vascular malformations. It involves inserting a catheter into an artery then injecting a contrast dye to make the blood vessels visible on x-ray images. The procedure allows physicians to evaluate the arteries for signs of disease.
Este documento describe un angiografía cerebral, un procedimiento médico que utiliza material de contraste y rayos X para ver cómo fluye la sangre a través del cerebro y diagnosticar posibles patologías como aneurismas, estenosis o malformaciones arteriovenosas. Antes del examen, el paciente debe someterse a exámenes médicos, firmar una autorización y seguir instrucciones como ayunar. El procedimiento implica insertar un catéter en la arteria para inyectar el material de contraste, y puede tener riesgos como reacciones alérgic
This document discusses cerebral aneurysms, which are bulges or ballooning in the walls of blood vessels in the brain. It defines aneurysms, lists their causes such as hypertension and smoking, and describes their signs and symptoms like severe headache and alterations in consciousness. The document outlines how aneurysms are diagnosed using CT scans, MRIs, lumbar puncture, and angiography. It then discusses treatment options for aneurysms like surgical clipping or coiling to repair the damaged blood vessel, as well as medical management using medications. Finally, it lists nursing care for patients with aneurysms such as monitoring vital signs, positioning, and preparing for potential emergency surgery.
Interventional radiology uses minimally invasive techniques guided by imaging to diagnose and treat medical conditions. Procedures use small incisions or catheters inserted through blood vessels to access internal organs. The Seldinger technique is commonly used, involving insertion of a guidewire and catheter through a needle into the femoral artery. A variety of catheters and guidewires are used depending on the target vessel. Angiography involves injecting contrast dye to visualize vessels. Interventional radiology suites contain specialized equipment like large X-ray tubes and digital image receptors to facilitate complex image-guided procedures.
This document discusses stroke, including its types, causes, pathophysiology, imaging findings, and clinical features. It provides the following key points:
1. Stroke is caused by ischemia or hemorrhage in the brain. The main types are cerebral infarction (80%), intracerebral hemorrhage (15%), and subarachnoid hemorrhage (5%).
2. Imaging plays an important role in assessing the parenchyma, vessels, perfusion, and penumbra to guide therapy and predict outcomes. Techniques include CT, MRI, CT/MR perfusion, and angiography.
3. CT findings evolve over time from hyperacute to chronic stages. Early signs include
This document provides an overview of Moyamoya disease. It defines Moyamoya disease as a progressive stenosis of the intracranial arteries, typically the internal carotid arteries and proximal middle and anterior cerebral arteries, accompanied by a compensatory network of collaterals at the brain's base. The cause is unknown but genetic factors are believed to play a role. Clinically, it can present with transient ischemic attacks, strokes, or hemorrhage. Diagnosis is based on neuroimaging findings on MRI, MRA, CTA or DSA showing the characteristic vascular changes. Treatment involves medical management as well as surgical revascularization procedures. Prognosis depends on the extent of vascular involvement and collateral formation.
This document provides an overview of arterial anatomy in the brain and imaging of strokes. It discusses the anterior and posterior circulations, variants and anomalies like aberrant internal carotid arteries and persistent stapedial arteries. It also covers the circle of Willis and acute cerebral ischemia/infarction, including pathophysiology, CT findings like ASPECTS scoring, CTA, perfusion CT, and MRI findings in the hyperacute, subacute and chronic stages. Specific topics like watershed infarcts and artery of Percheron infarction are also mentioned.
This document provides an outline and overview of key topics related to stroke. It begins with definitions and classifications of stroke, including transient ischemic attack (TIA) and different types of stroke. It then covers risk factors, pathophysiology, signs and symptoms, investigations, and management approaches for stroke. Specific sections address hemorrhagic versus ischemic stroke, localization of stroke syndromes, and differentiating features between anterior and posterior circulation strokes. Differential diagnoses are also listed. The document aims to present essential information on stroke for medical education purposes.
This document provides an outline for a presentation on stroke. It begins with an introduction defining stroke and classifying it as either transient ischemic attack (TIA), progressive stroke, or completed stroke. It then covers the types and risk factors of stroke, including modifiable and non-modifiable risk factors. The pathophysiology of both ischemic and hemorrhagic stroke is explained. Signs and symptoms of stroke are outlined, including localization of symptoms based on hemisphere affected. Investigations, prognostic factors, and management of both acute stroke and long-term prevention are summarized.
Cerebral venous thrombosis (CVT) is an uncommon type of stroke caused by a blood clot in the brain's venous sinuses or veins. It has a significant morbidity. Common presentations include headache, seizures, and long-lasting neurological deficits. Diagnosis is made through imaging studies like MRI and MRV. Treatment involves management of increased intracranial pressure, seizures, and anticoagulation with heparin or thrombolytics to prevent extension of clots. Prognosis depends on factors like impaired consciousness, underlying cause and location of clots. Most patients recover without sequelae, but mortality can be high if left untreated.
This document discusses hemorrhagic stroke, including intracerebral and subarachnoid hemorrhage. Intracerebral hemorrhage is caused by bleeding into the brain tissue and accounts for 10-15% of strokes. It has high mortality, especially if the patient is in a coma. Subarachnoid hemorrhage is caused by bleeding into the subarachnoid space, often due to ruptured aneurysms. Both require imaging like CT or MRI to diagnose and determine treatment, which may include surgery to remove hematomas or clip aneurysms. Complications include cerebral vasospasm, rebleeding, and hydrocephalus. Secondary stroke prevention focuses on controlling risk factors and treating
This document discusses stroke and conditions that can mimic stroke. It begins by defining stroke as a sudden neurological deficit caused by arterial ischemia or hemorrhage. While ischemic stroke diagnosis is often straightforward, clinical diagnosis is inaccurate 10-30% of the time as other conditions like infections, seizures, or tumors can appear similar. The document then discusses using a pattern-based approach to differentiate arterial ischemic strokes from stroke mimics based on imaging appearance over time from acute to chronic stages. Specific vascular territories, imaging sequences, and distinguishing features of common mimics like seizures and tumors are reviewed.
This document summarizes imaging findings related to subarachnoid hemorrhage (SAH). It describes that SAH appears as hyperdense linear structures on CT and hyperintense on FLAIR MRI. The location of blood can localize the source of bleeding such as anterior communicating artery aneurysms presenting with blood in the interhemispheric fissure. Complications include vasospasm, hydrocephalus, and superficial siderosis. Reversible cerebral vasoconstriction syndrome is also discussed, appearing as multifocal "string of beads" narrowing on angiography that resolves within 12 weeks.
This document discusses radiological findings of cerebral infarction on CT scans. It describes how early CT signs such as a hyperdense middle cerebral artery can help identify acute ischemic stroke within the first few hours. It also explains the pathophysiology of cytotoxic and vasogenic edema that develops in the brain during the first days following a stroke, and how this edema appears on CT scans. Identifying these early signs accurately on CT is important for determining if patients may benefit from thrombolytic therapy.
Cerebral Venous Thrombosis - Dr. KEO VEASNA Keo Veasna
Cerebral venous thrombosis is an uncommon form of stroke caused by thrombosis of cerebral veins and sinuses. It has a variable clinical presentation including headache, focal neurological deficits, and altered mental status. Diagnosis is made through neuroimaging tests like CT, MRI and MRA. Treatment involves anticoagulation with heparin or warfarin. Prognosis is generally good, though seizures, hydrocephalus and visual loss are potential complications. Risk of recurrence depends on presence of thrombophilias.
Subarachnoid hemorrhage is caused most commonly by the rupture of a saccular aneurysm. The rupture causes blood to fill the subarachnoid space, which can lead to neurological deficits or death. Treatment involves securing the aneurysm through surgical clipping or endovascular coiling to prevent rebleeding, as well as managing complications like vasospasm, hydrocephalus, and seizures. Outcomes depend on the grade and location of the initial bleed and development of delayed cerebral ischemia.
This document discusses the pathology of stroke and includes several case studies. It covers topics such as the types, etiology, pathogenesis, clinical features and complications of stroke. It also discusses transient ischemic attacks, hypertension and its complications and pathologies, arterial malformations, global ischemia, and venous infarcts. Microscopic features of infarction at various time points are also addressed.
DIGITAL SUBTRACTION ANGIOGRAPHY IN CEREBROVASCULAR DISEASE AND PERSPECTIVE.pptxNeurologyKota
This document discusses digital subtraction angiography (DSA) for diagnosing cerebrovascular diseases. It begins by introducing DSA as the gold standard technique for visualizing blood vessels through fluoroscopy and contrast injection. It then covers the indications for DSA including vascular diseases and tumors. The document provides details on the technique, approach for ischemic infarction cases, signs of acute ischemia, and examples of non-atherosclerotic vasculopathies that can be identified with DSA such as dissection, moyamoya disease, and fibromuscular dysplasia.
This document discusses C.N.S. vascular malformations, specifically arteriovenous malformations (AVMs) and dural arteriovenous fistulas (DAVF). It covers the definition, types, clinical presentation, radiographic features, grading systems, complications and treatment options for each condition. Key points include that AVMs are congenital lesions with direct connections between arteries and veins, while DAVFs are acquired lesions resulting from damage to venous structures. Presentations can include hemorrhage, seizures, and neurological deficits. Diagnosis is made through CT, MRI, and catheter angiography. Management depends on the size, location, and severity of the lesion.
Definition of stroke and cerebrovascular disorders and pathophysiology of cerebral infarct and CT imaging overview of acute-subacute and chronic infarcts and penumbra.
causes of cerebral edema , Radiological signs of acute infarct and hemorrhagic infarct and comparison of MRI and CT in the diagnosis of acute infarct
Role of diffusion weighted imaging (DWI) and diffusion perfusion mismatch
This document discusses cerebral haemorrhage (ICH), which accounts for 10-15% of strokes. ICH can result from several mechanisms, including hypertension (47-66% of cases), cerebral amyloid angiopathy (CAA), and vascular malformations. CAA typically affects the elderly and causes lobar ICH that is often recurrent or involves multiple simultaneous haemorrhages. Vascular malformations like arteriovenous malformations (AVMs) and cavernous angiomas are a common cause of ICH in young, non-hypertensive patients. Imaging techniques like CT and MRI can identify vascular malformations and help determine the underlying cause of ICH.
This document provides a menu of 21 different nervous system conditions and tumors. It then provides detailed descriptions and imaging examples for several key items on the menu, including hydrocephalus, cerebrovascular accidents (CVAs/strokes), CVA subtypes, astrocytomas, meningiomas, acoustic neuromas, pituitary adenomas, various types of spina bifida, Arnold Chiari malformation, spinal stenosis, disc herniations, and examples of calcified choroid plexus and pineal gland. The document serves as an educational reference for understanding various pathologies that can affect the brain and spinal cord.
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Colistin is a polymyxin antibiotic produced by Bacillus polymyxa that is effective against most gram-negative bacteria. It fell out of favor due to nephrotoxicity but remains a treatment of last resort for multidrug-resistant infections. There are two forms, colistin sulfate and colistimethate sodium, which are dosed differently and have different mechanisms of action, pharmacokinetics, and toxicity profiles. Resistance can develop with use but remains relatively rare currently.
This document discusses various methods for monitoring the central nervous system (CNS) during and after surgery. It describes cerebral perfusion monitoring techniques like cerebral blood flow measurements, transcranial Doppler ultrasonography, near-infrared spectroscopy, and jugular bulb oximetry. Regional perfusion is also monitored using brain tissue partial oxygen tension. Cerebral metabolism is assessed using cerebral microdialysis. Cerebral function is evaluated with the bispectral index, approximate entropy, and auditory evoked potentials. The document provides details on how each technique is performed and what clinical information it provides about CNS oxygenation, blood flow, and function.
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Chest x. ray interpretation and teachingsamirelansary
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2. Examples and descriptions are given for interpreting findings related to mediastinal masses, pleural effusions, atelectasis, pneumothorax and other lung abnormalities. Signs related to vascular structures like aneurysms are also outlined.
3. The document serves as a teaching guide for radiological interpretation and diagnosis, summarizing key signs and patterns seen for different diseases on chest x-rays.
Colistin is a polymyxin antibiotic produced by Bacillus polymyxa that is effective against most gram-negative bacteria. It fell out of favor due to nephrotoxicity but remains a treatment of last resort for multidrug-resistant infections. There are two forms, colistin sulfate and colistimethate sodium, which are not interchangeable. Dosing is complicated due to lack of standardization. Colistin works by disrupting bacterial membranes. While resistance is still rare, its increased use has led to some resistant strains emerging.
Chest x. ray interpretation and teachingsamirelansary
1. The document discusses various radiological signs seen on chest x-rays related to different disease processes and conditions. It provides descriptions of findings related to lung lesions, pleural diseases, pulmonary vascular abnormalities and other pathologies.
2. Examples of signs described include the appearance of mediastinal lesions, pleural effusions, lung opacities, findings associated with lobar collapse, and distributions of opacities related to specific conditions.
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2) Examples include the deep sulcus sign indicating pleural free air, the air crescent sign seen in invasive aspergillosis, the silhouette sign depicting a pericardial cyst, and the CT halo sign associated with various conditions including invasive aspergillosis.
3) Accompanying each sign is an illustration and example chest x-ray or CT image, with a brief explanation of the clinical significance of each radiographic finding.
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This case describes a 45-year-old male presenting with agitation, fever, hypertension, tachycardia, and other signs consistent with serotonin syndrome after ingesting Paxil, Gravol, ibuprofen, and smoking crack cocaine. The document discusses the diagnostic criteria and causes of serotonin syndrome and recommends supportive care and medications like cyproheptadine, benzodiazepines, beta-blockers, chlorpromazine, and dantrolene for treatment. Cyproheptadine appears to be an effective and safe treatment option for mild to moderate cases based on case reports and series.
This document defines key terms and concepts related to mechanical ventilation and interprets blood gas results to guide ventilator adjustments. It describes various ventilator modes, appropriate initial settings, priorities for weaning, and criteria for extubation. Volume control delivers a set tidal volume while pressure control uses a fixed pressure. Pressure-regulated volume control aims for a target minute ventilation. Complications include barotrauma, pneumonia, and cardiac/GI issues. Physical exams and pressure patterns can localize causes of acute deterioration. Neurologic, cardiovascular, and pulmonary status must be optimized before extubation.
This document discusses new insights into treatment strategies for critically ill patients, including optimal antibiotic dosing and the potential benefits of extended infusion of antibiotics. It also reviews evidence on the use of aerosolized colistin, inhalation antibiotics, statins, probiotics, and prophylactic antibiotics in preventing infections like ventilator-associated pneumonia in ICU patients. While some studies found decreased infection rates, ICU stay, or ventilation time with these approaches, larger trials are still needed to determine clear effects on mortality or define best practices. The document emphasizes individualizing care based on pharmacokinetic factors and calls for more research on optimization of antibiotic use in critical illness.
Mixed connective tissue disease (MCTD) is a rare autoimmune disorder with features of lupus, scleroderma, rheumatoid arthritis, and polymyositis. It is characterized by high levels of antibodies against ribonucleic proteins. Diagnostic criteria require 3 of 5 clinical features plus positive serology. Over time, many patients evolve symptoms meeting criteria for other connective tissue diseases. Pulmonary, renal, and cardiac involvement are common complications. Prognosis depends on degree of organ involvement, with 5-year mortality of 8-19% reported.
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This document contains summaries of several research points related to critical care. It discusses findings that propofol may limit recovery after brain injury in adults, that cardiac dysfunction is associated with mortality after traumatic brain injury, that vitamin D deficiency predicts sepsis in critically ill patients, and that neuromuscular blocking agents are associated with lower mortality in mechanically ventilated sepsis patients. It also summarizes research showing that a bundle of measures was effective at reducing ventriculitis associated with external cerebral ventricular drainage. Finally, it finds that critical illness is characterized by reduced intestinal absorption of glucose and lower expression of glucose transporters and taste receptors.
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5. Clinical Features
Cerebral Proliferative
Angiopathy
Moyamoya
Seizure: 45%
Headache: 41%
Focal deficits: 16%
Hemorrhages (12%):
33% single -- 67% recurrent
Prognosis: poor
Infarction: 50-75%
TIA: 50-75%
Seizures, headaches
Hemorrhages
Rare: choreiform, cognitive or
psychiatric changes
Prognosis: variable
If a patient with suspect CPA presents with HEMORRHAGE
consider HEMORRHAGIC ANGIOPATHY
6. More facts about Moyamoya
• 10-20% associated with sickle cell disease, NF-1, Down
Syndrome, previous cranial irradiation
• <10% associated with congenital cardiac anomalies, renal-
artery stenosis, giant cervicofacial hemangiomas,
hyperthyroidism
• Genetic component:
– 10% of Japanese & 6% of US pts have a 1st degree relative
– Associated w/abnormalities in chromosomes 3,6,8, & 17
• None of these associations are seen with CPA
7. Pathology Features
Cerebral Proliferative
Angiopathy
Moyamoya
Altered internal elastic
lamina & smooth
muscle cells
Collagenous thickening
of veins
Intermingled normal
neural tissue
Smooth muscle
hyperplasia
Irregular elastic lamina
No inflamacion
8. CT Features
Cerebral Proliferative
Angiopathy
Moyamoya
Areas of dense contrast
enhancement which may
be focal, lobar or
hemispheric
Collateral deep perforators
& pial vessels (Ivy sign)
Cortical Infarcts
Calcium in old infarcts
Hemorrhage
Cerebellum always nl
Hemorrhage:
Consider Hemorrhagic Angiopathy
9. Hemorrhagic Angiopathy: CT
3 pts with Hemorrhagic Angiopathy show intraparenchymal bleeds.
Hemorrhages are much less common in CPA.
10. Angiography Features (1)
Cerebral Proliferative
Angiopathy
Moyamoya
Intermingled nl brain
parenchyma
No dominant feeders
Fast capillary transit
Transdural blood supply
Late stenosis (ICA, M1-2, A1-2):
39%
Aneurysms (12%)
Mildly enlarged draining veins
Dilated perforating
arteries
Generally bilateral
Spares posterior
circulation arteries
Early stenosis of ICA,
M1 & A1
Aneurysms
11. Angiography Features (2)
Cerebral Proliferative
Angiopathy
Hemorrhagic
Angiopathy
Intermingled nl brain
parenchyma
No dominant feeders
Fast capillary transit
Transdural blood supply
Late stenosis
Aneurysms (12%)
Blush may be focal, lobar or
hemispheric
Low incidence of bleeds
Intermingled nl brain
parenchyma
No dominant feeders
Fast capillary transit
No transdural blood supply
No stenoses
No aneurysms
Small pseudo-tumoral blush;
usually subcortical
High incidence of bleeds
18. Early arterial phase (left) & late arterial phase (right) demonstrates nl size arterial feeders
& slightly early draining veins.
Hemorrhagic Angiopathy: Angiography
19. Moyamoya: angiography,
different stages
Narrowing of ICA, M1, A1 Narrowing of ICA with
“Puff-of-Smoke”,
diminished cortical flow.
Obliteration of ICA,
disappearance of Puff-of-Smoke,
further reduction of cortical flow.
20. MR T2WIs & lateral angiogram show focal CPA in the right frontal lobe.
Cerebral Proliferative Angiopathy :
MR & Angiography
21. Cerebral Proliferative Angiopathy: MR
Source MRA (left) shows multiple hypertrophied arteries, MRA frontal view
(center) shows stenosis of left MCA & CPA, T2WI (right) shows abnormal blood
vessels & gliosis in left hemisphere.
22. Cerebral Proliferative Angiopathy: MR
MRI studies (different pts) show multiple flow voids on T1WI (left), FLAIR (center) &
after Gdt administration (right). Note intermingled normal brain in all pts.
24. Cerebral Proliferative Angiopathy: MR Perfusion
MTT, rCBF & rCBV are increased due to capillary & venous ectasia. In classic brain
AVMs MTT is decreased due to rapid shunting.
CBV CBF MTT
26. Cerebral Proliferative Angiopathy: MR
Perfusion
Lasjaunias P. et al. Cerebral proliferative angiopathy, clinical and angiographic description of an entity different from cerebral AVMs.
Stroke. 2008 Mar: 1-8.
T1WI post Gd, TTP, rCBV & rCBF maps in an 11-year-old girl with headaches
shows left frontoparietal CPA. MRI demonstrate increase CBV & CVF indicating
hypervascularization in lesion & decreased TTP in nidus and surrounding areas
suggesting the ischemic nature of the disease.
30. Moyamoya: Vascular MR
Different patients: MRA shows stenosis of both MCAs & large perforators (left). Center
shows stenosis of left MCA. MR perfusion (right) shows low rCBF in deep regions of
both hemispheres.
31. Treatment
Cerebral Proliferative
Angiopathy
Moyamoya
Targeted embolization
Increase cortical blood
supply:
Synangiogenesis or calvarial
burr holes increase cortical
blood supply by recruiting
additional dural arteries
Antiplatelet Tx
Calcium channel
blockers
Surgery:
Synangiogenesis or
calvarial burr holes
Bypass ECA to ischemic
zone is feasible
32. Hemorrhagic Angiopathy: Response to
Radiation therapy
Pre & Post radiation Tx angiography performed on hemorrhagic angiopathy pts. Pre
images demonstrate pseudo tumoral blush at time of ICH with rapid capillary transity.
Post Tx images show excellent response to irradiation.
Pre Treatment Post Treatment Pre Treatment Post Treatment
33. Conclusions
Both cerebral proliferative angiopathy &
Moyamoya are arterial proliferative conditions
leading to stenoses in proximal vessels.
Both are ischemic arterial conditions.
Proliferative angiopathy and hemorrhagic
angiopathy have to be considered as a group of
disorders different from classical brain AVMs.
34. Conclusions
Treatment of Moyamoya aims to an improvement in
arterial supply by direct (bypass) or indirect
(synangiogenesis or calvarial burr holes)
revascularization techniques.
Proliferative angiopathy pts. can be candidates for
arterial revascularisation treatments. In some instances
they can benefit from targeted embolizations.
Hemorrhagic angiopathy has a rapid response to the
radiotherapy.
35. References
Scott R. et al. Moyamoya Disease and Moyamoya Syndrome. NEJM
2009;360:1226-37.
Bacigaluppi S, Dehdashti AR, Agid R, Krings T, Tymianski M, Mikulis
DJ.Neurosurg The contribution of imaging in diagnosis, preoperative
assessment, and follow-up of moyamoya disease: a review. Neurosurg
Focus. 2009; 26:E3a
Lasjaunias P. et al. Cerebral Proliferative Angiopathy, Clinical and
Angiographic Description of an Entity Different From Cerebral AVMs.
Stroke. 2008 Mar: 1-8.
Paolo Tortori-Donati, Andrea Rossi, C. Raybaud. Pediatric Neuroradiology:
Brain, Head , Neck, and Spine. Springer Berlin Heidelberg New York. 2005.
291-297.
Lasjaunias P, Ter Brugge K.G., Berenstein A. Surgical Neuroangiography.
Volume 3: Clinical and Interventioal Aspects in Children. Springer. 2006:
35-39.
37. Case # 1
Patient presents with
stroke symptom of
less than 2 hours.
Non contrast head CT
was performed and
shows a left dense
MCA (arrow).
38. Following the CT of the head, this CTA was performed :
Do you consider the left MCA to be occluded? This
MIP was interpreted as the MCA being patent.
Case # 1
40. Case # 1
Catheter angiogram
shows dissected left
ICA. There is cross
filling from right
injection to level of
occlusion (arrow).
Pial collaterals supply
territory of left MCA
thus filling it with
contrast.
41. Case # 1- Teaching Point
On the CTA the dense clot-filled M1 segment of
the left MCA appears isodense to contrast filled
arteries.
Collateral filling of the ipsilateral MCA branches to
the distal end of the clot resulted in a CTA that
gave the false appearance being normal.
Catheter angiography confirms these findings. If
CTA findings do not correspond with patient’s
symptoms, additional studies using different
techniques may be needed.
42. Case # 2
Patient complained of left sided hemiplegia
and left facial numbness lasting approximately
1 hour.
CTA was performed, two MIP coronal views are
shown (next slide), no early ischemic findings
were observed.
Vasculature and brain parenchyma were
symmetrical. Both ICAs had calcifications.
44. Case # 2
Immediately after the CT the patient underwent MRA
which shows occluded left ICA but cross filling of left
sided intracranial arteries via the circle of Willis.
45. Re-windowing the coronal and axial MIPs show calcification in
the left ICA (arrow) which confirms occluded artery as seen on
MRA. Note that with narrow window settings (left) the
calcification is not appreciated.
Case # 2
46. Case # 2 – Teaching Point
Primary collateral blood flow created a
symmetrical vascular picture of the distal
brain vessels and the dense intra-arterial
calcification in the left ICA masked the total
vessel occlusion when the CTA was viewed
with narrow window settings.
We have seen similar findings in three other
patients. Wide windows should be used to
avoid this problem.
47. Case # 3
Patient presented with acute left
MCA stroke symptoms.
CTA showed no occlusions; VR images
are shown (next slide).
48. Case # 3
Both MCAs are patent and left A1 segment of the ACA is not
visualized, bone obscures visualization of the petrous portions
of the ICAs. The posterior circulation is not seen entirely.
49. Case # 3
Widening the window (right side image) allows one to see that
the petrous portion of the left ICA (arrow) is narrowed when
compared to the opposite side. This finding is difficult to see
with regular window (left image) settings due to similar
densities at vessel/bone interface.
50. Case # 3
Axial MIPs with wide window settings show narrowed
petrous (arrows) left ICA when compared to right ICA
(arrowhead).
51. Case # 3- Teaching Point
With normal window settings, distinguishing
between adjacent bone and opacified vessel
may be difficult.
Separation of blood vessel/bone interface
necessitates wide window settings.
52. Case # 4
Patient had an acute right posterior
circulation infarct confirmed by non-contrast
head CT.
CTA demonstrated diffuse vascular irregularities
and narrow intracranial vessels.
The basilar artery and both P1 segments were
poorly visualized, VR images are shown (next
slide).
53. VRs of the circle of Willis show a narrowed basilar artery, non
visualization of the PCAs and adequate proximal anterior
circulation.
Case # 4
54. Case # 4
Axial MIPs show apparently complete circle of Willis, noticed
that, however vessel opacification is poor suggesting stenosis
(not seen) leading to poor blood flow to these arteries.
55. Case # 4
MIP axial image shows occlusion of the right ICA.
56. Case # 4- Continuation
Angiography confirmed the severe basilar
stenosis and right ICA occlusion.
Most of the arterial supply to the right cerebral
hemisphere was via right ophthalmic artery
and right PCA and not via the anterior
communicating artery as suspected from the
CTA.
57. Case # 4
Right external carotid artery injection
shows opacification of right MCA territory.
Lateral view of ECA injection
shows opacification of right
MCA territory.
58. Left ICA injection shows poor opacification of the right MCA
territory implying inadequate cross filling through ACommA.
Left vertebral artery injection
shows opacification of right MCA
territory.
Case # 4
59. Left vertebral artery injection
shows opacification of right MCA
territory.
Case # 4
60. Case # 4- Teaching Point
The status of the circle of Willis suggested by
the CTA was misinterpreted because of
patient’s low arterial input of contrast and
non-visualization of the collateral supply by
the right ophthalmic and right posterior
communicator artery.
The degree of narrowing of the basilar artery
was overestimated on CT.
Hemodynamic alterations were thought to be
responsible for the patient’s symptoms.
61. Case # 5
Patient presented with acute stroke symptoms
suggesting involvement of left posterior
circulation. CTA showed left occipital
hypodensity.
Axial MIPs are shown (next slide).
62. Case # 5
The transition between left P1 and P2 segments is not well visualized, but small
distal PCA branches show opacification implying that these arteries are patent
(click for sequential MIPs from CTA).
63. VR images show normal basilar artery. The right vertebral artery is dominant while
there is a vessel in the region of the left sided one. A discrepant finding with
respect to the MIPS is that both PCAs are not seen past their proximal segments on
these images probably due to the fact that they were excluded from the
reformations.
Case # 5
64. Case # 5
Injection into the right subclavian artery shows occlusion of
proximal vertebral artery with recanalization cephalad by
collaterals.
65. Case # 5
The right vertebral artery filled
via muscular collaterals and
there was slow flow to the
basilar artery. The left PCA is
occluded (arrow) past its P2
segment while the right sided
one is patent.
66. Case # 5
Injection into left vertebral artery shows that it ends in PICA
thus the vessel seen on the CTA cannot be the vertebral artery
but is probably a vein draining into the marginal sinus.
67. Case # 5- Teaching Point
Initially, there were discrepant findings between the
MIPs and VR images, the latter showing occlusion of
both PCAs. Catheter angiogram showed occluded
left PCA. Despite visualization of the presumed left
vertebral artery on CTA, angiogram showed it be
occluded. Moreover, the right vertebral was
proximally occluded and recanalized distally. The
static nature of CTA does not allow one to visualize
delay circulation times which may have been related
to patient’s symptoms.
68. Case # 6
Patient presented to the hospital after a
peripheral interventional procedure with signs
of a right MCA infarct. Embolic infarct was
suspected. CTA is shown in next slide.
70. Case # 6
Coronal MIPs show left MCA fenestration (circle) and
incompletely seen right M1 segment but with good opacification
of the ipsilateral sylvian branches.
71. Case # 6
VR images confirm left MCA
fenestration (circle) and
adequate filling of right
MCA despite symptoms
corresponding to that side.
72. Case # 6
Angiogram confirms left fenestration (circle). On the right, there is a similar
fenestration but its superior limb is occluded (arrow) explaining the patients
symptoms.
73. Case # 6- Teaching Point
CTA showed patent right MCA. This artery
was however fenestrated and the superior
limb of the fenestration was occluded
resulting in a basal ganglia/capsular infarction.
The fact that the inferior limb of the
fenestration was patent gave the false
impression that the entire left MCA was
patent. This was suspected and lead to
catheter angiogram and attempted
thrombolysis.
74. Case # 7
Patient presented with posterior circulation
infarct symptoms and CTA showed an unusual
configuration of the top of the basilar artery.
75. Case # 6
Sagittal MIP (left) shows irregular basilar artery termination (arrow). This
finding cannot be confirmed on the VR image (right) as the basilar artery apex
is inseparable from adjacent bone.
76. Case # 6
Catheter angiogram shows clot occluding distal basilar artery.
The definitive diagnosis could be made on CTA and required this
study.
77. Case # 6- Teaching Point
Contrast and/or clot may be of similar density
to bone and inseparable from it on VR images.
This is dependent on window settings and
time of study acquisition. Some times,
changing window setting may solve this
problem but others times the problem may
persist. Suspected defects seen on MIPs may
necessitate confirmation by catheter
angiography.
78. Discussion
• Stroke is the end product of a dynamic cascade of
events that culminates with tissue death.
• CTA information is only a snapshot of entire process.
• CTA may reveal distinct phases of disease process or
patient characteristics that serve as confounding factors
in imaging, such as
– recanalization of prior occlusion
– intra-arterial clot that is as dense as IV contrast
– collateral flow that may be primary or secondary
– symmetrical collateral flow that may be insufficient under
hypoperfusion situations.
79. Discussion
• Technical factors such as slice thickness , type of
reconstructions, suitable window settings and
MIP/VR interactive assessment at the work station
may improve assessment of distal branch occlusion
and intra-vascular densities.
• Keep in mind, when assessing a patient with acute
stroke symptoms, that there is a high likelihood that
chronic findings and/or unusual flow patterns may
be related to the patient’s symptoms.
80. Suggested Image Assessment
• Assess all acquired imaging settings
• Alter window level and center when assessing MIPs and VRs
to find calcifications, clots, dissections and stenoses that
may be either concealed or overestimated
• Assess 3D images dynamically, changing vessel bifurcations
angles
• Keep in mind that you are dealing with a dynamic disease
with possible associated chronic findings;
• Keep in mind that venous and arterial systems may be
contrasted and overlapping
• Look for possible collateral flow
89. GOOD LUCK
SAMIR EL ANSARY
ICU PROFESSOR
AIN SHAMS
CAIRO
elansarysamir@yahoo.com
Global Critical Care
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Wellcome in our new group ..... Dr.SAMIR EL ANSARY