Diagnostic and prognostic utility of computed tomography perfusion imaging in posterior circulation acute ischemic stroke : a systematic review and meta-analysis

Background: Computed tomography perfusion (CTP) imaging could be useful in the diagnosis of posterior circulation stroke (PCS) and in identifying patients who are likely to experience favorable outcomes following reperfusion therapy. The current study sought to investigate the diagnostic and prognostic capability of CTP in acute ischemic PCS by performing a systematic review and meta-analysis. Methods: Medline/PubMed and the Cochrane Library were searched using the terms: "posterior circulation", "CT perfusion", "acute stroke", and "reperfusion therapy". The following studies were included: (1) patients aged 18 years or above; (2) patients diagnosed with PCS; and (3) studies with good methodological design. Pooled sensitivity (SENS), specificity (SPEC), and area under the curve (AUC), computed using the summary receiver operating characteristic (SROC) curves, were used to determine diagnostic/prognostic capability. Results: Out of 14 studies included, a meta-analysis investigating diagnostic accuracy of CTP was performed on nine studies. Meta-analysis demonstrated comparable diagnostic accuracy of CTP to non-contrast computed tomography (NCCT) (AUCCTP: 0.90 [95% CI 0.87-0.92] vs. AUCNCCT: 0.96 [95% CI 0.94-0.97]); however, with higher pooled sensitivity (SENSCTP: 72% [95% CI 57%-83%] vs. SENSNCCT: 25% [95% CI 17%-35%]) and lower specificity (SPECCTP: 90% [95% CI 83%-94%] vs. SPECNCCT: 96% [95% CI 95%-98%]) than NCCT. Meta-analysis to determine prognostic capability of CTP could not be performed. Conclusions: CTP has limited diagnostic utility in acute ischemic PCS, albeit with superior diagnostic sensitivity and inferior diagnostic specificity to NCCT. Further prospective trials are required to validate the prognostic capability of CTP-derived parameters in PCS.