CT Perfusion in Acute Ischemic Stroke: A Comparison of 2-Second and 1-Second Temporal Resolution

In the nonischemic hemisphere, GM and WM regions of interest are placed as shown on the left part of the figure. In the ischemic vascular territory, the GM region with significantly reduced CBF but normal or elevated CBV is outlined as a “suspected penumbra” region of interest. The GM region with significantly reduced CBF and significantly reduced CBV is outlined as a “suspected core” region of interest. All regions of interest were used to determine quantitative perfusion values only; they were not used to predict final tissue fate (final tissue fate was not verified by follow-up imaging).

CTP scoring system in relationship to ASPECTS. M1, M2, M3, insular ribbon, caudate head, lentiform nucleus, internal capsule, anterior cerebral artery, PCA/occipital lobe, and PCA/thalamus were assigned 1 point each if nonaffected and 0 points if affected. Maximum score (healthy tissue) = 10, minimum score (complete infarction) = 0. For each case, CBF (TAR + NVT) and CBV (NVT) CTP lesion scores were derived from the CBF and CBV color maps, respectively.

Left panel: Example of a case with good source data quality. Note color map quality is almost identical for 2-second TR (column 1) versus 1-second TR (column 2) by using DC and MS (columns 3 and 4) techniques. Right panel: Example of a case with low dataset quality. Note that color map quality at 2-second TR is slightly reduced when using DC (columns 1 and 2) and significantly reduced when using MS (columns 3 and 4) processing techniques.

Box-and-whisker plots comparing 2-second and 1-second TR perfusion values.