Clinical application of CT gemstone spectral imaging in assessing therapeutic efficacy of transcatheter arterial chemoembolization for hepatocellular carcinoma

Objective: To discuss the clinical application of CT gemstone spectral imaging (GSI) in assessing therapeutic efficacy and in follow-up evaluation of hepatocellular carcinoma (HCC) after transcatheter arterial chemoembolization (TACE) treatment. Methods: The clinical data of 30 patients with pathologically-roved HCC, who were encountered during the period from Feb. 2013 to Oct. 2014, were retrospectively analyzed. One to 3 months after TACE, CT GSI and DSA were performed in all patients; the average interval between the two examinations was 2-4 days. The mixed energy (QC) and energy spectrum (Mono) images were obtained by single CT scanning; ADW4.6 workstation and GSI-view software were used to make postprocessing of images. The following two methods were adopted to make observation: (a) QC plain scan, the arterial phase and portal venous phase were used to make observation; (b) to observe the optimal single energy, iodine/water basis material image and spectrum characteristics. Two experienced assistant chief -physicians who engaged in abdominal imaging diagnosis separately and independently made the evaluation of the images on the post-processing workstation. The results were compared with DSA findings, and the sensitivity, specificity and other indicators of the two methods were calculated. The diagnostic abilities of the two methods were compared using Chi-square test. Results: After TACE, reexamination detected 154 lesions in the 30 patients, among which DSA showed enhancement in 100 lesions and non-enhancement in 54 lesions. The sensitivity and specificity of (a) method were 72% (72/100) and 77.8% (42/54) respectively, while the sensitivity and specificity of (b) method were 97% (97/100) and 94.4% (51/54) respectively; the differences in the sensitivity and specificity between the two methods were statistically significant (χ² = 23.04 and χ² = 7.11 respectively, P < 0.05). The coincidence rate of (a) method with DSA was medium (47.0%, K = 0.47, P < 0.01), while the coincidence rate of (b) method with DSA was good (91.0%, K = 0.91, P < 0.01). Conclusion: Compared with conventional CT scan, GSI scan can significantly improve the detection rate of small and multiple lesions without increasing the radiation dose. Based on the different characteristics of the energy spectrum images, GSI can reflect the homology of the tumors, objectively indicate whether a lesion is a recurrence or a metastasis, and effectively differentiate the liver tumor that is lack of blood supply from other diseases, thus, more accurate evaluation of TACE efficacy can be made. (authors)