Computed Tomography Angiography Compared with Computed Tomography Perfusion in the Diagnosis of Cerebral Vasospasm: A Systematic Review and Meta-Analysis.

Introduction: Cerebral vasospasm (CV) is a serious complication after subarachnoid hemorrhage; however, swift identification can be challenging. Computed tomography perfusion (CTP) directly measures tissue perfusion and may better screen for CV compared with other modalities. This systematic review summarizes studies assessing the diagnostic performance of computed tomography angiography (CTA) and CTP in identifying CV.

Methods: The search strategy drew from English language publications in the PubMed, Embase, Medline, and Cochrane databases from January 1996 to September 2021. Diagnosis of CV by digital subtraction angiography was the reference standard. Pooled sensitivity, specificity, positive predictive values (PPV), negative predictive values (NPV), positive likelihood ratios, negative likelihood ratios, and summary receiver operating characteristic curve were calculated. The methodological index for nonrandomized studies tool was employed to assess the quality of the studies.

Results: The search generated 22 studies. Seven CTA studies and 6 CTP investigations provided sufficient data for meta-analysis. Following pooled estimates, CTA carried a sensitivity of 0.76 (95% confidence interval [CI], 0.72-0.80), specificity of 0.93 (95% CI, 0.92-0.95), PPV of 0.77 (95%, 0.76-0.79), and NPV of 0.81 (95%, 0.79-0.82). CTP carried a sensitivity of 0.86 (95%, 0.81-0.92), specificity of 0.97 (95%, 0.95-0.98), PPV of 0.94 (0.89-0.98), and NPV of 0.94 (0.91-0.97). Using the methodological index for nonrandomized studies tool, the evidence was rated as overall moderate quality.

Conclusions: This meta-analysis on the diagnostic performance of CTA and CTP in identifying CV suggests that CTP may carry greater diagnostic accuracy compared with CTA. The clinical significance of this difference should be delineated through future prospective studies.