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

Prognostic value of relative cerebral blood volume (rCBV) in patients with recurrent glioblastoma multiforme treated with bevacizumab

BACKGROUND: To assess whether the early monitoring of the effects of bevacizumab in patients with recurrent glioblastoma multiforme (GBM) using perfusional dynamic susceptibility contrast (DSC) magnetic resonance imaging (MRI) before and after the beginning of anti-angiogenic therapy is predictive of treatment response. METHODS: Thirteen patients with recurrent GBM underwent perfusion MRI with relative cerebral blood volume (rCBV) mapping before (T0) and after the beginning (T1) of bevacizumab treatment. Recurrence Regions of Interest (RoIs) were positioned on the enhancing component of tumoral tissue revealed by post-contrast T1-weighted images. The rCBV measurements on the corresponding maps were made before and after the start of the anti-angiogenic therapy. The Cox proportional hazards model and the Kaplan-Meier method were used with the log-rank test to establish whether pre- and post-bevacizumab rCBV predicted progression-free survival (PFS). We tried to assess if there was a correlation between rCBV at T0 and rCBV at T1 using the Pearson's correlation coefficient. RESULTS: In the univariable analysis, rCBV was significantly predictive of PFS at T0 (HR= 5.3, p=0.003) and at T1 (HR=4.14, p=0.04). Similarly, in the multivariate Cox model analysis, rCBV was predictive of PFS at T0 (HR=4.4, p=0.04) and T1 (HR=4.2, p=0.02). PFS was longer in patients whose rCBV was less than 4.50 ml/100g at T0 and less than 1.83 ml/100g at T1 than in patients with higher rCBV values. There was a moderate positive correlation between rCBV at T0 and rCBV at T1 (P=0.032, R=0.546). CONCLUSIONS: Despite the limited number of enrolled patients, rCBV assessed using DSC-MRI through the parameter rCBV is proved reliable in predicting the effects of anti-angiogenic treatment in patients with recurrent GBM