Resident Division of Neurosurgery, University of Ottawa Markham, Canada
Introduction: Cerebral vasospasm is a serious complication following subarachnoid hemorrhage(SAH). Although early treatment improves outcomes, swift identification can be a challenge. CTP measures tissue perfusion and may offer improved diagnostic performance in screening cerebral vasospasm over other modalities such as CTA and TCDs. This systematic review and meta analysis summarizes studies assessing the diagnostic performance of CTA and CTP in identifying cerebral vasospasm.
Methods: The search strategy drew from English language publications in the PubMed, Embase, Medline and Cochrane databases from January 1996 to September 2021. The primary outcome was diagnostic performance of CTA and CTP in diagnosing cerebral vasospasm following spontaneous aneurysmal SAH, using DSA as the reference standard. Pooled sensitivity, specificity, PPV, NPV, LR+, LR- and SROC curve were calculated. MINORS tool was employed to assess the quality of the studies.
Results: The search generated 22 studies, of which 8 directly compared CTA to DSA, 12 compared CTP to DSA, and two included both CTA and CTP. Seven CTA studies and six CTP investigations provided sufficient data for meta-analysis. Following pooled estimates, CTA carried a sensitivity of 0.76 (95% CI, 0.72 - 0.80), specificity of 0.93 (0.92 - 0.95), positive predictive value of 0.77 ( 0.76 - 0.79), negative predictive value of 0.81 (0.79 - 0.82). CTP carried a sensitivity of 0.86 (0.81 - 0.92), specificity of 0.97 (0.95 - 0.98), positive predictive value of 0.94 (0.89 - 0.98), negative predictive value of 0.94 (0.91 - 0.97). Using the MINORS tool, the evidence was rated as overall moderate quality.
Conclusion : This meta analysis on the diagnostic performance of CTA and CTP in identifying cerebral vasospasm, the largest and most robust on the topic so far, suggests that CTP may carry greater diagnostic accuracy compared to CTA. The clinical significance of this difference merits delineation through future prospective studies.
