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Neuroimaging CAAGT opics for Discussion • Intracranial Haemorrhages • Ischaemic Stroke • Intracranial Masses • Spinal cord compression • Cauda Equina Syndrome • Associated Mass Effect Intracranial Haemorrhages What are the main types of intracranial haemorrhages?Intracranial Haemorrhages • Extra-dural • Sub-dural • Subarachnoid • Parenchymal/intra-cerebral • Intra-ventricularWhen is CT preferable over MRI?An aside on T1 vs T2When is CT preferable over MRI? • Acute trauma • Unstable patient • CT is better to look for haemorrhages • Time to perform CT vs MRI: 5sec vs 30minCase 1:Subdural Haemorrhage Etiology of SDH: • Tearing of bridging veins in subdural space Risk Factors for SDH: • Trauma, anticoagulants, cerebral atrophy which is common in elderly and alcoholicSubdural Haemorrhage Radiological features: • Crescentic shape • SDH cannot cross midline of skull • SDH can cross the suture linesCase 2:Epidural/ extradural Haemorrhage • Etiology of EDH: • Torn middle meningeal artery, associated with skull fracture secondary to trauma • Radiological features: • Lenticular shape • EDH can cross midline of skull • EDH cannot cross the suture lines • Associated with skull fractureCase 3Subarachnoid haemorrhage (SAH) Radiological features: • Sensitivity of CT is strongly influenced by both the amount of blood and the time since the haemorrhage. • Hyperattenuating material filling the subarachnoid space - around the circle of Willis, Sylvian fissure, interpeduncular fossa • Clinical correlation with LP needed Different types of intraparenchymal haemorrhagesIntracerebral haemorrhage • Causes and radiologial features: • Trauma : Contusions within the frontal and temporal poles • Aneurysm /AVM : Can be associated with SAH and perform CT angiogram follow by DSA • Tumour related haemorrhage : Associated with tumour and perform MRI to assess the extent of underlying tumour • Hypertension : Basal ganglia, brainstem and cerebellar involvement • Cerebral amyloid angiopathy : Recurrent lobar haemorrhage and convexity SAH, perform MRI to look for haemosiderin depositions and siderosis • Cerebral venous sinus thrombosis: Occur within the venous infarct, perform CT venogramCase 4Does MRI have a role in stroke?What MRI sequence is extremely sensitive and specific for acute stroke? Diffusion (DWI)Case 6Glioblastoma Multiforme T1 • hypo to isointense mass • central heterogenous signal (necrosis, intratumoural hemorrhage) T1 C+ (Gd) • enhancement is variable but is almost always present • typically peripheral and irregular with nodular components • usually completely surrounds necrosis T2/FLAIR • hyperintense • surrounded by vasogenic oedemaCerebral cavernous venous malformation MRI • MRI is the modality of choice, demonstrating a characteristic “popcorn” or "berry" appearance with a rim of signal loss due to susceptibility weighted sequences.ominent blooming onColloid Cyst • Benign epithelial lined cysts • Can present with acute and profound hydrocephalus Radiological features: • Well-delineated hyperattenuated mass on nonenhanced CT at the level of foramen on Monro • Hyperintense on T1 • Isointense to brain on T2Cerebral Abscess Radiological features CT – Hypodense mass with smooth peripheral enhancement MRI - High signal on T2, Smooth peripheral enhancement on post contrast imaging - Restricted diffusion within the abscess cavity is useful to make diagnosisDifferentials of intracranial mass - Tumour : Malignant (primary and secondary) and benign - Abscess - HaematomaCase 7Summary - Intracranial haemorrhages - Intracranial mass - Acute stroke - Spinal cord and cauda equina compression msw55@cam.ac.uk