Makindo Medical Notes

Brain CT Collection

Arachnoid Cyst

🫧 Expected imaging findings:
• Well-circumscribed extra-axial cyst with CSF density on CT and CSF signal on MRI.
• No enhancement with contrast and no restricted diffusion.
• Often causes mass effect (sulcal effacement, midline shift) if large, but no surrounding oedema.
• Common locations: middle cranial fossa, posterior fossa, suprasellar region.
⚠️ Usually incidental; symptomatic cases cause headache, seizures, focal deficits or hydrocephalus.

Meningioma

🧠 Expected imaging findings:
• Extra-axial, dural-based mass; often hyperdense on non-contrast CT.
• Vivid homogeneous enhancement post-contrast.
• Classic dural tail sign on MRI/contrast CT.
• May show hyperostosis or calcification adjacent to the lesion.
• Causes mass effect and often vasogenic oedema in underlying brain.
⚠️ Symptoms depend on location (seizures, focal deficit, raised ICP).

Subarachnoid Haemorrhage

🩸 Expected imaging findings:
• On non-contrast CT: hyperdensity in basal cisterns, sulci, and fissures (“star sign”).
• Blood may layer in the ventricles (intraventricular extension).
• Early CT (first 6–12 hours) is most sensitive; sensitivity falls with time.
• CT angiography may show aneurysm; LP (xanthochromia) if CT negative and suspicion high.
🚨 Clinical clue: thunderclap headache ± meningism, collapse, reduced GCS.

Lung Mets with and without Contrast

🎯 Expected imaging findings:
• Multiple rounded pulmonary nodules of varying size (“cannonball” pattern possible).
• Non-contrast CT shows distribution and calcification; contrast improves mediastinal/hilar assessment and vascular relationships.
• Look for pleural deposits, lymphangitis carcinomatosis (septal thickening), or effusions depending on tumour type.
• Haematogenous spread often gives peripheral, well-defined nodules.
⚠️ Always interpret in clinical context: primary tumour history, weight loss, haemoptysis.