Detection of symptomatic vasospasm after subarachnoid haemorrhage: initial findings from single time-point and serial measurements with arterial spin labelling.

Abstract

[Objectives]To detect symptomatic hemispheres during the postoperative course of subarachnoid haemorrhage (SAH) using arterial spin labelling (ASL). [Methods]Eighteen patients with aneurysmal SAH were included; four exhibited symptomatic vasospasm postoperatively. All patients underwent ASL on days 9–10 (single time-point ASL). Nine patients underwent serial measurements of ASL (serial ASL) on days 1–2, 9–10 and 13–21, and seven patients also underwent imaging on days 4–7. CBF in the posterior part of the MCA territory was measured, and the ipsilateral/contralateral ratio of CBF was calculated. Differences between symptomatic hemispheres and others underwent ROC analysis. [Results]Single time-point ASL revealed that CBF_{day9-10} and CBF_{i/c_day9-10} were significantly lower in symptomatic hemispheres than in asymptomatic hemispheres (P < 0.001). Serial ASL was significantly decreased on CBF_{day4-7} compared with CBF_{day1-2} and on CBF_{day9-10} compared with CBF}_{day4-7}, and significantly increased on CBF_{day13-21} compared with CBF_{day9-10}. ROC analysis of single time-point ASL revealed that AUC for CBF_{day9-10} was 0.95, significantly higher than CBF_{i/c_day9-10} (P < 0.001). ROC analysis of serial ASL showed that AUC for CBF_{day9-10} was 0.93 and significantly higher than CBF_{day9-10/day1-2} and CBF_{i/c_day9-10} (P < 0.001). [Conclusions]Single time-point ASL revealed significant CBF reduction in symptomatic hemispheres compared with asymptomatic hemispheres. Serial ASL showed time-dependent CBF changes after SAH.