Visual grading system for vasospasm based on perfusion CT imaging: comparisons with conventional angiography and...

Area of Science:

• Neurology
• Radiology
• Medical Imaging

Background:

• Acute subarachnoid hemorrhage can lead to vasospasm, a critical complication affecting cerebral blood flow.
• Accurate characterization of vasospasm is essential for timely and effective patient management.

Purpose of the Study:

• To compare visual grading of perfusion CT (PCT) maps with quantitative analysis for vasospasm detection.
• To evaluate the diagnostic performance of PCT parameters against digital subtraction angiography (DSA).

Main Methods:

• Prospective study of 33 patients with subarachnoid hemorrhage, involving 40 paired PCT and DSA examinations.
• Independent review of PCT maps (MTT, CBF, CBV) by a neuroradiologist and neurologist, grading five anatomical regions.
• Assessment of 19 arterial segments for vasospasm by a blinded neuroradiologist using DSA as the gold standard.

Main Results:

• Mean transit time (MTT) and cerebral blood flow (CBF) PCT maps showed strong correlation with DSA findings (R² = 0.939 and 0.907, respectively).
• MTT maps achieved 92% sensitivity and 86% specificity; CBF maps demonstrated 75% sensitivity and 95% specificity for vasospasm detection.
• Good interobserver agreement was observed for MTT (kappa = 0.789) and CBF (kappa = 0.658) scoring.

Conclusions:

• A simple visual grading system for PCT maps is proposed for suspected vasospasm.
• This visual approach demonstrates favorable comparison to DSA, supporting its clinical utility.
• MTT maps are recommended for screening, while CBF maps are suggested for confirming vasospasm.