Estimation of ischemic core in acute ischemic stroke with CT angiography and non-contrast CT: Attenuation changes in ASPECTS regions vs. automated ASPECTS scoring

Abstract

PurposeReperfusion therapies for acute ischemic stroke due to large-vessel occlusion (AIS-LVO) are highly time-dependent, and large infarction is related to poor outcomes and risk of symptomatic hemorrhage. It is of significance to investigate and optimize the screening means and selection criteria for reperfusion therapies to identify more appropriate patients with better outcomes. This study aimed to compare the performance of attenuation changes vs. automated Alberta Stroke Program Early CT Score (ASPECTS) and using CT angiography (CTA) source images vs. non-contrast CT (NCCT) in distinguishing the infarction extent of ischemic core volumes ≥ 70 ml within different time windows.MethodsA total of 73 patients with AIS-LVO who received multimodal CT were analyzed. The automated software was used to calculate ASPECTS. Attenuation change was defined as the sum of products of relative Hounsfield unit (rHU) values times weighting factors of all 10 ASPECTS regions. rHU value of each region was the HU of the ischemic side over that of the contralateral. The corresponding weighting factors were the regression coefficients derived from a multivariable linear regression model which was used to correlate regional rHU with ischemic core volumes, because each region in the ASPECTS template is weighted disproportionally in the ASPECTS system. Automated ASPECTS and attenuation changes were both calculated using CTA and NCCT, respectively.ResultsAttenuation changes were correlated with ischemic core volumes within different time windows (Rho ranging from 0.439 to 0.637). In classification of the ischemic core ≥ 70 ml, the performances of attenuation changes were comparable with ASPECTS (area under the curve [AUC] ranging from 0.799 to 0.891), with DeLong’s test (P = 0.079, P = 0.373); using CTA (AUC = 0.842) was not different from NCCT (AUC = 0.838).ConclusionAttenuation changes in ASPECTS regions were correlated with ischemic core volumes. In the classification of infarction volumes, attenuation changes had a high diagnostic ability comparable with automated ASPECTS. Measurement of attenuation changes is not involved in complicated scoring algorithms. This measurement can be used as an available, rapid, reliable, and accurate means to evaluate infarction extent within different time windows. The usefulness of infarction volumes measured by attenuation changes to identify more appropriate patients for reperfusion therapies can be validated in future clinical trials.

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

“…21 This pathophysiological process manifests as a decrease in radiographic attenuation on CT images as early as 6 hours after the incidence of stroke. 21 Although not as sensitive as DWI, the change in radiographic attenuation on CT images reflects the changes in the brain tissue itself. We deemed that this was a potential advantage of the CT density-derived volume of the IC compared with blood flow-derived volumetric parameters.…”

“…Bouslama et al 3 assessed postreperfusion final infarct volume and functional outcomes for both early- and late-presenting patients using the same software as that used in the aforementioned studies and reported that the volume of the IC based on NCCT was similar to that obtained with RAPID CTP. The water uptake in the brain tissue increases after ischemic stroke due to intracellular cytotoxic edema, extracellular ionic edema, extracellular vasogenic edema, and subsequent blood-brain barrier breakdown 21 . This pathophysiological process manifests as a decrease in radiographic attenuation on CT images as early as 6 hours after the incidence of stroke 21 .…”

“…The water uptake in the brain tissue increases after ischemic stroke due to intracellular cytotoxic edema, extracellular ionic edema, extracellular vasogenic edema, and subsequent blood-brain barrier breakdown 21 . This pathophysiological process manifests as a decrease in radiographic attenuation on CT images as early as 6 hours after the incidence of stroke 21 . Although not as sensitive as DWI, the change in radiographic attenuation on CT images reflects the changes in the brain tissue itself.…”

Ischemic stroke prediction of patients with carotid atherosclerotic stenosis via multi-modality fused network

“…Stroke medicine is a quite suitable application for DL because vast amount and wide variety of brain imaging data need to be collected, combined and analyzed in making clinical decisions. Most of previous studies adapted DL algorithms based on brain MRI data have focused on acute ischemic stroke, either for the infarction detection and segmentation, or for the clinical prognosis evaluation (Yu et al, 2020;Li et al, 2022;Shin et al, 2022). However, few has concerned about predicting risk of ischemic stroke.…”