Background: Manual volumetric analysis of CT perfusion (CTP) in acute ischemic stroke (AIS) patients using the OsiriX software is an established and accurate technique.
Hypothesis: Automated software will produce accurate measurements compared to manual volumetric measurements.
Methods: We reviewed 120 inpatients from 2010-2014 with AIS and a CTP from the acute setting. We used the automated Olea Sphere software to generate perfusion maps with oscillation index singular value decomposition (oSVD) and Bayesian probabilistic deconvolution. We used the manual OsiriX software to draw regions-of-interest delineating the stroke core on cerebral blood volume (CBV) and penumbra on cerebral blood flow (CBF) maps of the original CTP. For Bayesian analysis we defined stroke core as relative CBF2 seconds, and penumbra as relative mean transit time >135%. For oSVD we defined stroke core as relative CBF2 seconds, and penumbra as absolute Tmax >6 seconds. We compared techniques with a Pearson correlation coefficient and linear regression.
Results: Both automated techniques had excellent correlation and agreement with the manual measurements (Table 1), but Bayesian deconvolution yielded superior agreement for CBV (Figure 1).
Conclusion: Automated CTP volumetric analysis in AIS patients is reliable and accurate. Bayesian deconvolution has superior agreement with manual measurements of stroke core. Automated volumetric methods have an inherent appeal in the acute stroke setting given their efficiency.