CNS, H&Neck Imaging Quizes

#WhatNext NF2 1. Post contrast images of whole neural axis. 2. Refer to neurology. 3. Family screening: CE MRI whole neural axis. 4. Look for ocular 👁️ abnormalities in pediatric patients.(More common) MZeba

HIV Encephalitis: 💫Affects subcortical and periventricular white matter, possibly the basal ganglia and thalamus. 💫Lesion Characteristics: T1: Hypointense, T2: Hyperintense, FLAIR: High signal 💫Enhancement: Generally no post-contrast enhancement; mild enhancement may occur in some cases. 💫Associated Findings: Cerebral atrophy and ventricular enlargement. MZeba

Progressive multifocal leukoencephalopathy (PML): A demyelinating disease which results from the reactivation of John Cunningham virus (JC virus) infecting oligodendrocytes in patients with compromised immune systems. 🧠CT: Asymmetric low attenuation in periventricular and subcortical white matter, contrasting with symmetrical hypoattenuation in HIV encephalopathy. MRI: 🧠Multifocal, asymmetric periventricular and subcortical involvement with minimal mass effect/enhancement. 🧠U-Fiber Involvement: Common in parieto-occipital regions; sharp peripheral border, hazy inner border. 🧠Signal Characteristics: T1: Hypo intense, T2: Hyperintense, no enhancement, patchy DWI restriction at lesion edges. 🧠Signs: 💫Milky Way Sign: Punctate high T2 signal lesions. 🏋️‍♀️Barbell Sign: Abnormality crossing the splenium. 🦐Shrimp Sign: Sparing of the dentate nucleus in the cerebellum. 🧠MR Spectroscopy: Reduced NAA, increased choline/lipids, lactate presence. 🧠MR Perfusion: Elevated at lesion edges, notably in progressive non-IRIS PML. Source: Radiopedia MZeba

PRES 🧭 Asymmetrical cortical and subcortical WM edema: parietal & occipital.. superior frontal sulcus +/- 🧭 Usually no restriction on DWI 🧭 Classic history: Acute HTN or chemotherapy. MZeba

Gnathic Osteosarcoma: 🦷 A subtype of osteosarcoma affecting the mandible (horizontal ramus) and maxilla (alveolar ridge, sinus floor, palate). 🦷 XR: Osteoblastic > Fibroblastic > Chondroblastic 🦷 Orthopantomography: Shows key signs such as the Garrington sign. 🦷CT Scan: 🦴Cortical involvement 🦴Soft-tissue extension 🦴Intramedullary bone extension 🦴Matrix calcification 🦷DD: 🦴Osteomyelitis: Inflammatory bone condition. 🦴Osteoma: Less aggressive, distinct appearance. (Source: Radiopedia) MZeba

Colloid Cyst 🧠♂️>♀️30-40Y 🧠0.3-4cm 🧠DWI: mild 🧠Rim enhancement: can be present 🧠Usually hyper dense on CT and high on T1. 🧠Paroxysmal headache MZeba

Orbital Floor Fractures: --- Decisions regarding the need for surgery revolve around: ❏ muscle entrapment causing opthalmoplegia ❏ enopthalmos. --- Orbital blow-out fractures occur when there is a fracture of one of the walls of orbit but the orbital rim remains intact. (Radiopedia)

Thalamic infarcts: -- Generally asymmetric and due to multiple emboli or small vessel ischemia. -- Bilateral thalamic infarction is uncommon. --- Causes include: 1. Artery of Percheron occlusion 2. Cerebral venous thrombosis 3. Top of the basilar syndrome (Radiopedia)

Pons: -- Supplied by vertebrobasilar circulation: 1. Medial branches of the superior cerebellar artery 2. Pontine branches of basilar artery, thalamoperforator arteries. -- The most common cause of ventral pontine damage is basilar artery thrombosis. -- Locked-in syndrome is one of the brainstem stroke syndromes and can occur as a result of a pontine stroke that damages the ventral brainstem, pyramidal bundles and corticobulbar tracts. (Radiopedia)

Lateral medullary syndrome: -- AKA Wallenberg syndrome -- Clinical syndrome caused by acute ischemia or infarction of the lateral medulla oblongata due to occlusion of the intracranial portion of the vertebral artery, PICA or its branches. -- Lateral medullary syndrome is the most prevalent posterior ischemic stroke syndrome. -- The triad of Horner's syndrome, ipsilateral ataxia, and contralateral hypalgesia will clinically identify patients with lateral medullary infarction. (Radiopedia)

Subacute Infarct: Unique: ➕ Positive enhancement ➖ No mass effect 1. 24 hours to 2 months 2. The CT hypodensity becomes more apparent and ADC values gradually increase and pseudo-normalize at 4 to 10 days. 3. Gyriform enhancement appears at 6 days and persists for as long as 2-3 months. 4. Edema peaks in 3-4 days and decreases after 7 days. 5. Hemorrhagic transformation usually occurs 2 to 7 days after ictus. MZeba (Applied Radiology)

🧠 CNS SBA Quizzes by MZeba --- Tumors 1. http://t.me/QuizBot?start=uGq2hAcU 2. http://t.me/QuizBot?start=esVYBcNc 3. http://t.me/QuizBot?start=qzygAoiD 4. http://t.me/QuizBot?start=3TxA546p 5. http://t.me/QuizBot?start=gDt719BN --- Infection 1. http://t.me/QuizBot?start=ppyZIKs9 2. http://t.me/QuizBot?start=EGHz4FO5 --- Vascular 1. http://t.me/QuizBot?start=2jnO1ef9 2. http://t.me/QuizBot?start=1TQ0UyTD 3. http://t.me/QuizBot?start=EGHz4FO5 --- Degenerative 1. http://t.me/QuizBot?start=ELEXbcdQ 2. http://t.me/QuizBot?start=xoRJWISF ---Traumatic BI 1. http://t.me/QuizBot?start=u6PE6iP4 2. http://t.me/QuizBot?start=vTr8FUdM --- H&N 1. http://t.me/QuizBot?start=d61l9j02 2. http://t.me/QuizBot?start=NVfOg6xL 3. http://t.me/QuizBot?start=W9yz8JfE 4. http://t.me/QuizBot?start=3lrNX3b0 --- Spine 1. http://t.me/QuizBot?start=HTWLvGXv 2. http://t.me/QuizBot?start=OT4hqvWl --- Review Quizzes 1. http://t.me/QuizBot?start=0FVO6Tos 2. http://t.me/QuizBot?start=PRYLc1Jn 3. http://t.me/QuizBot?start=CogmRLqb 4. http://t.me/QuizBot?start=7rLqAygJ 5. http://t.me/QuizBot?start=Y9NI3wnK 6. http://t.me/QuizBot?start=NkDjkG7l 7. http://t.me/QuizBot?start=T5pSsv9m 8.http://t.me/QuizBot?start=fcV7inEA MZeba

Vertebral dissection #WhatNext 1. Management depend upon the level above V4, or below V4 2. Above V4: ... No anticoagulants as there is increase risk of intraparenchymal/SA hge. ... Go for endovascular coiling/clipping. 3. Below V4: ... If no intraparenchymal or SAH, go for anticoagulation. MZeba

Vertebral Artery Dissection: -- Factors predicting outcome include: 1. Intracranial extension: subarachnoid hemorrhage 2. Size of the contralateral vertebral artery 3. Presence and size of posterior communicating arteries and P1 segment of the posterior cerebral artery: collateral flow 4. Size of posterior fossa ischemia (Radiopedia)

Idiopathic Orbital Pseudotumor: -- Division into a number of subgroups according to location: 1. Lacrimal pseudotumor (dacryoadenitis) 2. Anterior pseudotumor: in the immediate retrobulbar fat 3. Posterior pseudotumor: in the fat at the orbital apex; distinguished from Tolosa-Hunt syndrome in that the cavernous sinus is spared 4. Myositis pseudotumor (myositis): predominantly involves the extraocular muscles and therefore mimic thyroid-associated orbitopathy (TAO) but unlike TAO it also involves the tendons 5. Optic perineuritis: involvement of the optic nerve sheath 6. Diffuse pseudotumor: affecting multiple compartments. (Radiopedia)

Tumefactive Demyelination:Practical points 1. Often there is no evidence of established multiple sclerosis, and many patients do not go onto to develop MS 2. Tumefactive demyelination is not necessarily benign, and patients can have a fulminant course ending in demise (e.g. Marburg variant of MS) 3. Lesions are centered on white matter and involve subcortical U-fibers 4. Less mass effect than expected for size 5. Incomplete leading edge enhancement is characteristic 6. CBV is lower than in tumors (Radiopedia)

Arrested hydrocephalus: -- Arrested hydrocephalus is defined as adequately shunted hydrocephalus -- Is stable ventriculomegaly without neurologic symptoms. -- Headache, cognitive decline, and seizure can signal decompensation. -- Endoscopic third ventriculostomy and ventriculo-peritoneal shunting are treatments. (McLone DG, Aronyk KE. An approach to the management of arrested and compensated hydrocephalus. Pediatr Neurosurg. 1993 Mar-Apr;19(2):101-3. doi: 10.1159/000120709. PMID: 8443094.)

(Radiopedia)

Normal Pressure Hydrocephalus ⚡Enlarge lateral & 3rd ventricle and relatively normal 4th ventricle ⚡Disproportionately enlarge subarachnoid space hydrocephalus. (Particularly sylvian fissure & basal cisterns) ⚡Tight high convexity with effacement of parafalcine sulci ⚡Aqueductal flow void ⚡Cinguoate sulcus sign: narrow posterior Cingulate sulcus compared to the anterior MZeba