Quantitative 4D transcatheter intraarterial perfusion MRI for standardizing angiographic chemoembolization endpoints

OBJECTIVE. The purpose of this study was to test the hypothesis that subjective angiographic endpoints during transarterial chemoembolization (TACE) of hepatocellular carcinoma are consistent and correlate with objective intraprocedural reductions in tumor perfusion determined with quantitative 4D transcatheter intraarterial perfusion MRI. SUBJECTS AND METHODS. In this prospective study, 18 consecutively registered patients underwent TACE in a combined MRI-interventional radiology suite. Three board-certified interventional radiologists independently graded the angiographic endpoint of each procedure using a previously described subjective angiographic chemoembolization endpoint scale. A consensus endpoint rating was established for each patient. Patients underwent quantitative 4D transcatheter intraarterial perfusion MRI immediately before and after TACE, and mean whole tumor perfusion was calculated from the images. Consistency of subjective angiographic endpoint ratings between observers was evaluated with the intraclass correlation coefficient. The relation between the endpoint ratings and intraprocedural transcatheter intraarterial perfusion MRI changes was evaluated with the Spearman rank correlation coefficient. RESULTS. The subjective angiographic chemoembolization endpoint rating scale showed very good consistency among all observers (intraclass correlation coefficient, 0.80). The consensus endpoint rating correlated significantly with both absolute (r = 0.54, p = 0.022) and percentage (r = 0.85, p < 0.001) reduction in intraprocedural perfusion. CONCLUSION. The subjective angiographic chemoembolization endpoint rating scale shows very good consistency between raters and significantly correlates with objectively measured intraprocedural perfusion reductions during TACE. These results support the use of the scale as a standardized alternative method in quantitative 4D transcatheter intraarterial perfusion MRI to classify patients on the basis of embolic endpoints of TACE.