CNS Radiology PDF

CNS Radiology __________________________________________________________ - Investigation used for evaluation of brain & skull Plain x-ray Skull CT Scan MRI MRA & MRV & CTA Angiogram Duplex U/S of carotid arteries Ultrasound for neonatal brain Main investigation for evaluation of brain & skull - Plai...

CNS Radiology __________________________________________________________ - Investigation used for evaluation of brain & skull Plain x-ray Skull CT Scan MRI MRA & MRV & CTA Angiogram Duplex U/S of carotid arteries Ultrasound for neonatal brain Main investigation for evaluation of brain & skull - Plain films are still initial investigation for disorders of bones of the skull – particularly fractures. - CT and MRI have become the standard investigations for disorders of the brain. - Axial sections are most important in head CT. Terminology - Radiodense –radiopaque (bright) - Radiolucent (dark) Contraindications of CT scan - Allergy - Renal Failure - Normal CT scan of the brain CSF is seen as water density (black) within ventricular system & subarachnoid space. White matter is relatively darker than grey matter The falx is denser (radio-opaque) than the brain. Large arteries & venous sinuses can be recognized when opacified by contrast medium. Posterior fossa may be obscured by artifacts from overlying temporal and occipital bone. - Goals of CT in the acute setting is to exclude ICH, which preclude thrombolysis, look for any early features of infarction & exclude other intracranial pathologies that may mimic a stroke, such as tumours. Contrast enhanced CT - Consequence of breakdown of blood brain barrier allowing contrast to enter the lesion particularly in neoplasm, infection, inflammation and certain stage of ischemia - Also it is helpful in demonstrating blood vessels. Cross sectional brain anatomy Supratentorial compartment - Cerebral hemispheres Basal Ganglia Thalamic nuclei Lateral Ventricles Hypothalamus Corpus callosum Infratentorial compartment - Cerebellum - Brain stem - 4th ventricle - Circle of wills? - Venous sinuses? __________________________________________________________ !1 Indications Method Plain x-ray skull Indications - Trauma Congenital Calcification: normal or abnormal (vascular, neoplasm) Metastasis: lytic /sclerotic Multiple myeloma Metabolic disorders CT scan (no contrast) - Trauma - Detection of blood - Strokes CT scan (with contrast) - Tumors - Infection - Vascular disorders MRI - Strokes, Tumors Infection Vascular disorders White matter disease Some cases of trauma - MRI is the best for acute Brain Infarction. - - Cerebral angiogram It is an invasive technique. It is the gold standard technique for assessment of intra & extra cranial vessels. Demonstrate vascular diseases (stenosis, occlusion, vascular malformation & tumor blood supply. Recently its main role for intervention purposes such as treatment of vascular malformation (aneurysm/ arterovenous malformation) or pre-operative embolization of vascular supply of tumor. MR Venography (MRV) Can be done either with or without (TOF) injection of contrast medium. Can confirm presence of venous thrombosis. Assess venous dural sinuses superficial & deep venous system. CT angiography is helpful in diagnosis of vascular diseases & abnormalities. __________________________________________________________ Timing - Acute 0-2 days - Sub-acute 3-7 days - Chronic >7 days -Acute hematoma (hypeRdense) -Subacute hematoma (Isodense) -Chronic hematoma (hypOdense) Ischaemic stroke - The 2nd most common cause of morbidity worldwide (after MI) & cause of acquired disability. - Examples: Cardiac embolism, Atherosclerotic embolism (fat -air), Thrombosis, & Arterial dissection - Global cerebral hypoxia (as is seen in drowning or asphyxiation) is, usually, considered separately. __________________________________________________________ !2 Intracranial heamorrhage - Itra-axial haemorrhage Intracerebral haemorrhage Basal ganglia haemorrhage Lobar haemorrhage, Pontine haemorrhage Cerebellar haemorrhage Intraventricular haemorrhage (IVH) Extra-axial haemorrhage - Extradural haemorrhage (EDH) - Subdural haemorrhage (SDH) - Subarachnoid haemorrhage (SAH) Heamorrhage Type Intracranial hemorrhage Features - ICH a collective term encompassing many different conditions characterised by extravascular accumulation of blood within different intracranial spaces. - A simple categorization is based on location. Risk Factors - Head injury, Family history of ICH - Alcohol abuse, Hypertension - Cigarette smoking - Drugs including amphetamines & MDMA (ecstasy) - Extreme physical exertion mom To diagnoe ICH these are needed:⭐ 1. Localization 2. Density 3. Shape Epidural hemmorhage Subarachenoid hemorrhage Intracerebral Subdural hemorrhage Hemorrhage Due to tear of bridging vien Cresent shaped " Cross the suture lines Doesn’t cross the midline Due to rapture of MMA Biconvex lenticular shaped # Skull fractures Doesn’t cross suture lines Crosses the midline Between arachnoid & pia matter Trauma (most commonly) Rapture of berry aneurysm Vascular malformation Hematologic disturbances, Tumors Most common cause is HTN Symptoms - Headache, sudden & severe or associated with a recent blow to the head Mcnamara - Headache, mild and long-lasting or accompanied by neck stiffness - Confusion, Drowsiness - Vomiting more than twice in 24 hours - Seizure, Coma Done by Maha Albarrak Good Luck !3