A comparative analysis of SCALE-CTP and RAPID in determining the affected brain volumes of patients with ischemic...

Computed tomography perfusion (CTP) is widely used to treat acute strokes. The affected brain volume, measured based on the threshold value in the calculated CTP map, has helped guide treatment decisions. We proposed a new software program developed for CTP analysis, SCALE-CTP, and compared the affected brain volumes estimated using RAPID and SCALE-CTP.

We recruited 362 individuals from the local hospital to evaluate the concordance between SCALE-CTP and RAPID in predicting affected brain volumes, including relative cerebral blood flow (rCBF) <30 % and time-to-maximum concentration (Tmax) > 6 s, and the mismatch volumes. Concordance correlation coefficients (CCC) and Bland-Altman plots were used to assess agreement. Subgroup analyses and comparisons with DWI-derived infarction areas were also performed, along with an evaluation of differences in clinical decision-making.

The calculated volumes from two different software showed excellent concordance (rCBF < 30 % volume: 0.91, Tmax > 6s: 0.88 volume, mismatch volume: 0.82). The concordance between the two software programs remains excellent in the subgroup analysis. In the subset of 38 cases, the differences between DWI-derived infarction area and rCBF < 30 % volume from both software were similar, while SCALE-CTP showed more variability. Their differences in clinical decision making were slightly different.

SCALE-CTP demonstrated strong agreement with RAPID in predicting affected brain volumes and shows potential as a reliable tool for guiding hyperacute ischemic stroke treatment. Further validation is needed to confirm its clinical utility.