▶️Initial non-con CT shows a 3cm hyperdense lobulated extra-axial mass in the expected region of the left MCA bifurcation, consistent with a giant aneurysm. There are associated peripheral calcifications
▶️ What is the cause of the surrounding hypodensity?
What is the cause for the surrounding hypodensity?
▶️Mass effect and/leakage from the aneurysm induces vasogenic edema which moves easily through the white matter and relatively spares the more dense gray matter.
▶️However, we also see more subtle hypodensity of the lateral temporal lobe cortex, suspicious for acute ischemia
▶️CTA shows filling of the partially thrombosed aneurysm
▶️CT perfusion shows reduced CBF and corresponding elevated Tmax within the left MCA territory
▶️I am not sure if the stroke is due to thromboembolism from intraaneurysmal thrombus or if it’s 2/2 altered flow kinetics given the large size 🤷🏻♂️ (no occlusion was seen)
▶️Thoughts welcome 🙏
▶️MR shows the hypointense aneurysm on T2 with mixed iso and hyperintensity on T1
▶️ADC nicely delineates the areas of shine through from vasogenic edema and low ADC value from cytotoxic edema 2/2 infarct
▶️The aneurysm was treated with flow diversion using a pipeline shield rather than coiling due to a wide neck.
▶️Follow up, shows persistent filling of the sac despite stent placement
Learning points:
💡 Most intracranial aneurysms are asymptomatic
💡 Complications include rupture and rarely stroke
💡 When you see vasogenic edema around an aneurysm you must worry about impending rupture/leaking (as shown below, 24 hours apart in a different patient)
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⭐️ Answer: petrous apicitis complicated by brainstem abscess
🔷Petrous apicitis can display the clinical triad of Gradenigo’s syndrome
1️⃣Otorrhea
2️⃣Cranial nerve 6 palsy
3️⃣Pain in distribution of trigeminal nerve
▶️Petrous apicitis usually occurs as a complication of otomastoiditis when the infection spreads to the skull base.
▶️The petrous apex is in close proximity to Dorello’s canal (where cranial nerve 6 runs through) and Meckel’s cave (where the trigeminal ganglion is located)
▶️CVT causes retrograde venous pressure leading to focal vasogenic edema
▶️Increased back pressure is characterized by dilated veins and petechial hemorrhage which can progress to large hematomas and ischemic neurological damage
🔷Two types of edema can develop:
1️⃣Vasogenic (from venous back pressure)
2️⃣Cytotoxic (ischemia)
🔷Risk factors:
💡 Up to 20% are idiopathic
1️⃣Trauma
2️⃣Tumor/malignancy (compression/invasion from meningioma)
3️⃣Infection
4️⃣Hormonal (pregnancy)
5️⃣Dehydration
🔷What is the most likely diagnosis in this 70 y/o F who lives with feral cats presenting w/ vomiting, diarrhea, leukocytosis, fever for 3 days and progressive decline in level of consciousness?
🔷CSF: initially normal, repeat a few days later ⬆️ WBC (lymphocyte predominant), ⬆️ Protein, normal glucose
🔷 South Central Asia and Southeast Asia appear to have the greatest number of cases
🔷Dogs are the most common reservoir 🐶 (bats in developed countries🦇)
🔷CLINICAL:
▶️Incubation period typically 3 weeks to 2 months (range 5 days to 6 months)
▶️Prodromal symptoms: fever, malaise, anxiety,
and itching at the inoculation site
💡Once in the body, the virus begins retrograde flow to extend to the dorsal root ganglion, which may correlate with neuropathic pain
▶️CNS manifestations: Mental status changes of excessive agitation and depression with hydrophobia and aerophobia
🔷35 y/o F w/ history of Li Fraumeni syndrome presents w/ intermittent left sided weakness and pain. The feeling is of heaviness, difficulty w/ grip, dropping objects and frequent falls. Episodes last for weeks to months. What is your diagnosis? 🧠
🎉Congrats to all the rad fellow matches today!!! 🍾
⭐️ Answer: Tumefactive demyelination (MS in this case)
🔷Imaging in this case is specific enough to diagnosis with confidence but we need extra caution in patients with genetic predisposition to malignancy
💡 In cases where imaging or clinical picture are atypical or discordant for demyelination (especially if there is a genetic disorder), it is best to refer to neurology for proper work up, possible trial of steroids and short imaging follow up
🚩 Be suspicious against MS if your patient has:
1️⃣Systemic symptoms (fever, weight loss, joint or skin symptoms, etc.)
2️⃣Seizures, hearing loss, meningitis signs, movement disorder, aphasia
3️⃣”Family history”
4️⃣Age (<20 or >50)
5️⃣Lesions are symmetric
6️⃣Hemorrhage or dense on CT
7️⃣Diffusion restriction other than leading edge
8️⃣Strokes
9️⃣Cysts
🔟Cortical infiltration
⭐️ 30 y/o presents w/ R sided weakness & fall. Pt had a recent admission ~4 months ago for headache, AMS, seizure & diplopia. Clinically stable until now.