Computed tomography perfusion and computed tomography angiography in vasospasm after subarachnoid hemorrhage.

Background: The aim of the study was to evaluate the effectiveness and reliability of a combined computed tomography angiography (CTA) and computed tomography perfusion (CTP) approach in the diagnosis of cerebral vasospasm after subarachnoid hemorrhage.
Methods: Nineteen patients with clinical signs of arterial vasospasm and positive transcranial Doppler (TCD) were enrolled and underwent CTP. Mean time transit (MTT), cerebral blood flow (CBF) and cerebral blood volume (CBV) values of 20 standardized ROI (regions of interest) were analyzed, and CTA used to measure the gauge of 26 arterial ramifications. CTA measurements were compared with those taken upon hospitalization. Of the 19 patients, 11 were scheduled for digital subtraction angiography (DSA), performed less than 12 hours after execution of the CTA-CTP protocol. The results were compared with findings of DSA and/or clinical follow-up and CT or TCD.
Results: Computed tomography angiography diagnosis of vasospasm was confirmed in all cases (100% sensitivity and 100% specificity), while CTP yielded 3 false negatives (70% sensitivity and 100% specificity). All patients sent for endovascular treatment had received diagnostic confirmation of vasospasm by angiography. CTP thresholds proved reliable in both diagnosis and indicating treatment.
Conclusions: Combined one-shot CT angiography and CT perfusion represents a valid alternative to DSA in the diagnosis and management of cerebral vasospasm.