Serial Quantitative Computed Tomography Perfusion in Aneurysmal Subarachnoid Hemorrhage

Area of Science:

• Neuroradiology
• Cerebrovascular Diseases
• Medical Imaging

Background:

• Computed tomography perfusion (CTP) assesses delayed cerebral ischemia (DCI) risk in aneurysmal subarachnoid hemorrhage (aSAH).
• Severe arterial narrowing significantly impacts perfusion, but effects of mild to moderate narrowing are less understood.
• Investigating perfusion changes in mild to moderate narrowing is crucial for predicting DCI.

Purpose of the Study:

• To investigate serial whole-brain CTP and computed tomography angiography (CTA) findings in aSAH patients with mild to moderate angiographic narrowing.
• To evaluate the correlation between arterial diameter and perfusion changes.
• To assess perfusion differences in patients with and without DCI.

Main Methods:

• Retrospective study of 18 aSAH patients with baseline and follow-up CTP/CTA.
• Analysis of 31 regions of interest per hemisphere across six levels, grouped by vascular territory.
• Measurement of arterial diameters at the circle of Willis and correlation with CTP values, DCI status, and vasodilator therapy response.

Main Results:

• Overall cerebral blood flow (CBF) and mean transit time (MTT) correlated with angiographic narrowing (R=0.49, p<0.04; R=-0.48, p=0.04).
• CBF changes correlated with arterial diameter in middle, posterior, and anterior cerebral artery territories (R=0.53-0.54, p<0.03).
• Prolonged MTT correlated with middle cerebral artery narrowing (R=0.52, p=0.03); DCI patients trended towards worsening CBF (p=0.055).

Conclusions:

• Mild to moderate angiographic narrowing in aSAH patients correlates with serial perfusion changes.
• Progressively worsening CBF was observed in patients who developed DCI.
• These findings highlight the importance of CTP/CTA in monitoring perfusion in aSAH with varying degrees of arterial narrowing.