In MRI of the brain, which sequence is MOST sensitive for detecting acute cortical vein thrombosis (cerebral venous sinus thrombosis)?
- A Susceptibility-weighted imaging (SWI) or gradient-echo T2* sequence ✓
- B Time-of-flight (TOF) MR venography
- C T1-weighted post-gadolinium with magnetisation transfer suppression
- D DWI with ADC map
Explanation
Susceptibility-weighted imaging (SWI) or gradient-echo T2* is the most sensitive MRI sequence for detecting acute cortical vein thrombosis. Deoxyhaemoglobin in the thrombus is paramagnetic, causing signal dephasing/blooming artefact (dark signal), making even small cortical veins with thrombus detectable — the 'blooming sign'. SWI is 97% sensitive for CVT. TOF MR venography may miss small cortical vein thrombi and show false-positive slow flow as 'filling defects.' Contrast MRV and T1 post-gadolinium detect the 'empty delta sign' in the dural sinuses. DWI detects ischaemic venous infarction but not the thrombosis itself.
Reference: Grainger & Allison's Diagnostic Radiology, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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