Diagnostic performance of CT cerebral blood volume colour maps for evaluation of acute infarcts; comparison with diffusion-weighted MRI within 12hours of major stroke onset.

BACKGROUND AND PURPOSE: Recent developments in treatment of ischemic stroke increased importance of defining limits of ischemic insult by imaging. Some studies postulated that CTP is a promising technique, which can discriminate between ischemic core and penumbra. In this study, we sought to evaluate diagnostic performance of CTP-CBV colour maps, regarded as a marker of acute infarct; in comparison with DWI.

MATERIALS AND

METHODS

We retrospectively analyzed 48 patients with CTA proved major ischemic stroke within 12hours of onset, they had DWI and CTP exams within 1hour of each other, regardless of order. DWI sizes were calculated. Sensitivity, specificity, PPV and NPV of CBV colour maps for identification of acute infarcts were calculated. ROC curve was constructed.

RESULTS

CBV colour maps missed a lot of small infarcts that were identified by DWI with an overall diagnostic accuracy of (62.5%) and low sensitivity (38.5%) for patients whom DWI size<70mL. Area under curve was 0.79. DWI size was an only predictor of abnormal CBV colour maps (P=0.005).

CONCLUSIONS

Assuming direct equivalence of DWI and CBV-based core might be unrealistic for individual patients in clinical practice. CBV colour maps are highly specific for acute infarcts, but with lack of sufficient sensitivity; particularly for small sized infarcts.