PURPOSE
To perform a pilot study to explore the effect of a new post-processing technique for 4D-CTA on speed and accuracy of the detection of intracranial vessel occlusions in acute stroke. This technique color-codes the contrast arrival time in the cerebral vasculature in 4D-CTA so that abnormally delayed vascular territories are easily detected.
METHOD AND MATERIALS
We selected 10 patients without and 10 patients with a confirmed single vessel occlusion on CTA from our database of acute ischemic stroke patients, so that occlusions of the ICA, MCA, ACA and PCA of varying subtlety were included. Whole-brain CT perfusion was performed on a 320 detector-row scanner. Color-coded 4D-CTA images were obtained by centering the color scale of vessel time-to-peak (TTP) on the modus of the TTP histogram. Temporal MIP of 4D-CTA with and without color-coding were evaluated in random order for the presence of vessel occlusion by to two neuroradiologists. Time-to-detection and accuracy of detection of vessel occlusions were evaluated.
RESULTS
One false-positive vessel occlusion was rated on color-mapping by both observers. Overall, the average time-to-detection decreased from 37.0s to 19.4s (p<0.03) and the average accuracy of vessel occlusion detection increased from 0.825 to 0.85 with color-mapping.
CONCLUSION
Color-mapping of cerebral vasculature in 4D-CTA improves the speed and may improve the accuracy of the detection of vessel occlusions in acute stroke patients.