Potential Approach to Quantifying the Volume of the Ischemic Core in Truncated Computed Tomography Perfusion Scans: A Preliminary Study

Abstract

Objective This study aimed to provide an alternative approach for quantifying the volume of the ischemic core (IC) if truncation of computed tomography perfusion (CTP) occurs in clinical practice. Methods Baseline CTP and follow-up diffusion-weighted imaging (DWI) data from 88 patients with stroke were retrospectively collected. CTP source images (CTPSI) from the unenhanced phase to the peak arterial phase (CTPSI-A) or the peak venous phase (CTPSI-V) were collected to simulate the truncation of CTP in the arterial or venous phases, respectively. The volume of IC on CTPSI-A (VCTPSI-A) or CTPSI-V (VCTPSI-V) was defined as the volume of the brain tissue with >65% reduction in attenuation compared with that of the normal tissue. The volume of IC on the baseline CTP (VCTP) was defined as a relative cerebral blood flow of <30% of that in the normal tissue. The volume of the posttreatment infarct on the follow-up DWI (VDWI) image was manually delineated and calculated. One-way analysis of variance, Bland-Altman plots, and Spearman correlation analyses were used for the statistical analysis. Results VCTPSI-A was significantly higher than VDWI (P < 0.001); however, no significant difference was observed between VCTP and VDWI (P = 0.073) or between VCTPSI-V and VDWI (P > 0.999). The mean differences between VDWI and VCTPSI-V, VDWI and VCTP, and VDWI and VCTPSI-A were 1.70 mL (limits of agreement [LoA], −56.40 to 59.70), 8.30 mL (LoA, −40.70 to 57.30), and −68.10 mL (LoA, −180.90 to 44.70), respectively. Significant correlations were observed between VDWI and VCTP (r = 0.68, P < 0.001) and between VDWI and VCTPSI-V (r = 0.39, P < 0.001); however, no significant correlation was observed between VDWI and VCTPSI-A (r = 0.20, P = 0.068). Conclusions VCTPSI-V may be a promising method for quantifying the volume of the IC if truncation of CTP occurs.