CT perfusion predicts secondary cerebral infarction after aneurysmal subarachnoid hemorrhage

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Abstract
Objective: To prospectively assess the diagnostic accuracy of CT perfusion (CTP) and transcranial Doppler sonography (TCD) for the prediction of secondary cerebral infarction (SCI) after aneurysmal subarachnoid hemorrhage (SAH). Methods: During 2 weeks after SAH, 38 consecutive patients completed an average of 3.5 CT/CTP and 10.7 TCD examinations at regular intervals as required by the study protocol. SCI was defined as delayed infarction on native CT between 3 and 14 days after SAH and developed in n = 14 patients (n = 24 without SCI). Analysis was based on examination dates before SCI. Common measures of diagnostic accuracy were calculated for qualitative CTP (visual color-map ratings from two blinded observers) and TCD assessments (mean flow velocity >120 cm/s in anterior, middle, and posterior cerebral artery territories). Quantitative measures, which for CTP were obtained from cortical a priori regions of interest corresponding to the vascular territories, were analyzed by binary logistic regression. Results: Time of prediction for SCI by CTP was at a median of 3 days (range 2 to 5 days) before manifestation of complete infarction on native CT. Visual assessment of time-to-peak (TTP) color maps performed best for the prediction of SCI with 0.93 sensitivity (95% CI: 0.7 to 1.0) and 0.67 specificity (95% CI: 0.53 to 0.7). On quantitative analysis, the odds ratio (OR) for 1 second of side-to-side delay in TTP was 1.4 (p = 0.01, Wald χ2 = 8.57, CI: 1.07 to 1.82). Daily TCD measures were not significantly related to SCI at any time before complete infarction on native CT. Conclusions: Time to peak as indicated by CT perfusion is a sensitive and early predictor of secondary cerebral infarction.