Cerebral blood flow is the optimal CT perfusion parameter for assessing infarct core

Area of Science:

• Neurology
• Radiology
• Medical Imaging

Background:

• CT perfusion (CTP) is a readily available tool for acute ischemic stroke imaging.
• Validation of CTP parameters for infarct core prediction is limited.
• Cerebral blood volume (CBV) has been proposed as a key predictor.

Purpose of the Study:

• To compare the predictive accuracy of CBV against other CTP parameters for infarct core in acute ischemic stroke.
• To validate CTP findings against contemporaneous diffusion MRI.

Main Methods:

• 98 CTP scans from 54 acute ischemic stroke patients were analyzed.
• CTP parameters including CBV, CBF, MTT, TTP, and Tmax were generated.
• Diffusion-weighted imaging lesions were manually outlined and compared with CTP maps using ROC analysis.

Main Results:

• Relative cerebral blood flow (CBF) demonstrated the highest accuracy (AUC, 0.79) in predicting infarct core, outperforming absolute CBV (AUC, 0.74).
• An optimal threshold of <31% of mean contralateral CBF was identified.
• Specificity was reduced by low CBF/CBV in non-infarcted white matter, particularly with reduced contrast intensity and leukoaraiosis.

Conclusions:

• CBF is a more accurate CTP parameter than CBV for predicting acute ischemic stroke infarct core, contrary to prior reports.
• No single threshold for CTP parameters can completely avoid false-positive regions in unaffected white matter.
• Optimized CTP acquisition and postprocessing are crucial for improving diagnostic accuracy and reducing false positives.