Related Experiment Video
Updated: Apr 28, 2026
A Magnetic Resonance Imaging Protocol for Stroke Onset Time Estimation in Permanent Cerebral Ischemia
Published on: September 16, 2017
Comparison of computed tomographic and magnetic resonance perfusion measurements in acute ischemic stroke:
Longting Lin1, Andrew Bivard1, Christopher R Levi1
1From the Stroke Research Program, Hunter Medical Research Institute (L.L., A.B., C.R.L., M.W.P.) and Department of Neurology, John Hunter Hospital (C.R.L., M.W.P.), The University of Newcastle, Newcastle, New South Wales, Australia.
Background And Purpose:
Magnetic resonance perfusion (MRP) and computed tomographic perfusion (CTP) are being increasingly applied in acute stroke trials and clinical practice, yet the comparability of their perfusion values is not well validated. The aim of this study was to validate the comparability of CTP and MRP measures.
Methods:
A 3-step approach was used. Step 1 was a derivation step, where we analyzed 45 patients with acute ischemic stroke who had both CTP and MRP performed within 2 hours of each other and within 9 hours of stroke onset. In this step, we derived the optimal perfusion map with the least difference between MRP and CTP. In step 2, the optimal map was validated on whole-brain perfusion data of 15 patients. Step 3 was to apply the optimal perfusion map to define cross-modality reperfusion from acute CTP to 24-hour MRP in 45 patients and, in turn, to assess how accurately this predicted 3-month clinical outcome.
Results:
Among 8 different perfusion maps included in this study, time to peak of the residual function (T(max)) was the only one with a nonsignificant difference between CTP and MRP in delineating perfusion defects. This was validated on whole-brain perfusion data, showing high concordance of T(max) between the 2 modalities (concordance correlation coefficient of Lin, >0.91); the best concordance was at 6 s. At T(max)>6 s threshold, MRP and CTP reached substantial agreement in mismatch classification (κ >0.61). Cross-modality reperfusion calculated by T(max)>6 s strongly predicted good functional outcome at 3 months (area under the curve, 0.979; P<0.05).
Conclusions:
MRP and CTP can be used interchangeably if one uses T(max) measurement.
