Spectral CT in evaluating the therapeutic effect of transarterial chemoembolization for hepatocellular carcinoma: A retrospective study

Abstract

This study aimed to investigate the value of computed tomographic (CT) spectral imaging in evaluating the effect of transarterial chemoembolization (TACE).The records of 67 patients with hepatocellular carcinoma (HCC) who had undergone dynamic spectral CT before treatment were selected for the study. Iodine concentrations pretreatment in liver parenchyma, the HCC lesion(s), portal vein, and aorta were measured from the decomposition images. The normalized iodine concentrations (NIC) were calculated. All of them underwent plain scan or contrast-enhanced CT post-treatment (approximately 4-6 weeks after TACE).The values of arterial phase normalized iodine concentrations (AP NIC) before TACE correlated with the grades of lipiodol deposition in tumors (r = 0.76, P < .001). However, there was no relationship between normalized iodine concentrations in the portal venous phase (PVP NIC) before TACE and the grade of lipiodol deposition (r = 0.17, P = .17). Values of AP NIC in residual tumors pre-TACE were significantly lower than those in partial lesions with deposition of iodized oil. The threshold AP NIC of 0.18 yielded an AUC of 0.895, 83.33% sensitivity, 81.03% specificity, 83.33% positive predictive value (PPV), and 82.76% negative predictive value, respectively. The survival probability in patients with AP NIC values pre-TACE ≥ 0.18 was higher than those whose AP NIC values pre-TACE were < 0.18 (P = .028).Spectral CT with quantitative analysis of AP NIC may help to evaluate the utility and predict the therapeutic effect of TACE. Values of AP NIC had high sensitivity and specificity for differentiating partial tumors with lipiodol deposition from those without lipiodol deposition.

Figure 1

Images after transarterial chemoembolization showed different types of iodine deposition. (A) Image showed complete accumulation which was assigned to grade III. (B) Image showed lipiodol deposition in some area of the tumor which was assigned to grade II. (C) Image after TACE showed little accumulation of iodine which was assigned to grade I. TACE = transarterial chemoembolization.

Figure 2

Box plots of the differences in parameters of spectral CT in different groups. CT = computed tomographic.

Figure 3

ROC curves for AP NIC in differentiating group A from group B. AP NIC = normalized iodine concentrations in the arterial phase, ROC = receiver operating characteristic.

Figure 4

Kaplan–Meier estimates of survival in both groups. Patients whose AP NIC values pre-TACE were ≥ 0.18 (group D) survived significantly longer than those with AP NIC values pre-TACE < 0.18 (group C) (P = .028). AP NIC = normalized iodine concentrations in the arterial phase, TACE = transarterial chemoembolization.