Correlation of Collateral Scores Derived from Whole-Brain Time-Resolved Flat Panel Detector Imaging in Acute Ischemic Stroke

Abstract

BACKGROUND AND PURPOSE: Flat panel detector CT imaging allows simultaneous acquisition of multiphase flat panel CTA and flat panel CTP imaging directly in the angio suite. We compared collateral assessment derived from multiphase flat panel CTA and flat panel CTP with collateral assessment derived from DSA as the gold-standard. MATERIALS AND METHODS:We performed a retrospective analysis of patients with occlusion of the first or second segment of the MCA who underwent pre-interventional flat panel detector CT. The hypoperfusion intensity ratio as a correlate of collateral status was calculated from flat panel CTP (time-to-maximum . 10 seconds volume/time-to-maximum . 6 seconds volume). Intraclass correlation coefficients were calculated for interrater reliability for the Calgary/Menon score for multiphase flat panel CTA and for the American Society of Interventional and Therapeutic Neuroradiology/Society of Interventional Radiology (ASITN/SIR) score for DSA collateral scores. Correlations of the hypoperfusion intensity ratio, multiphase flat panel CTA score, and the ASITN/SIR score were calculated using the Spearman correlation.RESULTS: From November 2019 to February 2020, thirty patients were included. Moderate interrater reliability was achieved for the ASITN/SIR DSA score (0.68; 95% CI, 0.50-0.82) as well as for the Calgary/Menon multiphase flat panel CTA score (0.53; 95% CI, 0.29-0.72). We found a strong correlation between the ASITN/SIR DSA and Calgary/Menon multiphase flat panel CTA score (r ¼ 0.54, P ¼ .002) and between the hypoperfusion intensity ratio and the Calgary/Menon multiphase flat panel CTA score (r ¼ À0.57, P , .001). The correlation was moderate between the hypoperfusion intensity ratio and the ASITN/SIR DSA score (r ¼ -0.49, P ¼ .006). The infarct core volume correlated strongly with the Calgary/Menon multiphase flat panel CTA score (r ¼ -0.66, P , .001) and the hypoperfusion intensity ratio (r ¼ 0.76, P , .001) and correlated moderately with the ASITN/SIR DSA score (r ¼ -0.46, P ¼ .01). CONCLUSIONS:The Calgary/Menon multiphase flat panel CTA score and the hypoperfusion intensity ratio correlated with each other and with the ASITN/SIR DSA score as the gold-standard. In our cohort, the collateral scoring derived from flat panel detector CT was clinically reliable.

The Compensation Index Is Better Associated with DSA ASITN Collateral Score Compared to the Cerebral Blood Volume Index and Hypoperfusion Intensity Ratio

“…HIR correlation with ASITN CS is well established, with studies showing a statistically significant correlation. The degree of correlation has been reported over a range of modest association (coefficient (r) = −0.33) [48] to moderate association (coefficient (r = −0.76) [19,49]. Our correlation was similar to Guenego et al [48], whereas it was lower than what was reported by Kurmann et al [19] and Ai et al [49].…”

“…The degree of correlation has been reported over a range of modest association (coefficient (r) = −0.33) [48] to moderate association (coefficient (r = −0.76) [19,49]. Our correlation was similar to Guenego et al [48], whereas it was lower than what was reported by Kurmann et al [19] and Ai et al [49]. The wide range of variation in the correlation coefficient is multifactorial.…”

“…Of the previously described quantitative CTP CS parameters, HIR has been the most studied. Several prior studies have demonstrated that HIR can serve as a reliable CS marker [19,48,49]. HIR correlation with ASITN CS is well established, with studies showing a statistically significant correlation.…”

“…Hypoperfusion intensity ratio (HIR) was defined as the volume of tissue with Tmax > 10 s divided by the volume of tissue with Tmax > 6 s [13]. Both the CBV Index and HIR parameters have each shown a correlation with infarct growth and with clinical outcomes following mechanical thrombectomy (MT) [14][15][16][17][18][19].…”

Current and future trends in acute ischemic stroke treatment: direct-to-angiography suite, middle vessel occlusion, large core, and minor strokes

“…Substantial evidence is already available that modern flat-panel detectors can provide clinically reliable measures for collateral status both for flat-panel CTA and for flat-panel CTP. [24] , [25] Moreover, flat-panel imaging is constantly evolving, and diagnostic accuracies for haemorrhage and/or ischemic lesions are comparable to multidetector CT. However, limitations remain in the case of motion artifacts and in discerning between gray-white matter differentiation.…”