Mixed Imaging on Port-Venous Phase of Contrast-Enhanced Dual-Source Dual-Energy Computed Tomography: A Measurement Method Based on Couinaud Segments
Authors: Jiang Changqin , Shen Lianfang , Xia Lichao , Sun Shihang , Fang Wei , Feng Qiang , Dong Haixia , Ma Zhijun 
Published: November 2018

Objective
The aim of this study was to evaluate the changes of the iodine value quantified on the Couinaud segments measured in port-venous phase using the iodine-mixed technique of contrast-enhanced dual-source dual-energy computed tomography (CT) scanning in different Child-Pugh stages of hepatitis B–induced liver cirrhosis.

Methods
Patients clinically diagnosed with hepatitis B–induced cirrhosis were prospectively engaged in our study. Each patient underwent multiphase iodine agent contrast-enhanced dual-source dual-energy CT scanning, and then the iodine-mixed imaging of port-venous phase was postprocessed. Iodine concentration was obtained for each segment based on the Couinaud segments. The volume of each segment and the total of the liver were measured and calculated using the postprocessing software of volume. All the cirrhosis patients were grouped into 3 subgroups based on the Child-Pugh stage method. Patients without cirrhosis were engaged for the control group. The iodine concentration, volume, and iodine storage among groups were analyzed by SPSS version 19.0. Single energy was used for the nonenhanced phase scanning, which was used for the radiation dosage comparison with dual-energy CT scanning.

Results
Two hundred three patients were ultimately enrolled in our study, including 148 patients with cirrhosis (Child A, 69; Child B, 51; Child C, 28) and 55 patients without cirrhosis as control subjects. The total volume and iodine storage of cirrhosis group were smaller than those of the control group (P < 0.001). Compared with the control group, the iodine concentration in each segment decreased with progression of cirrhosis. The volume, iodine concentration, and iodine storage of the right hepatic lobe and left medial segment decreased with cirrhosis severity (P < 0.001). There was no significant difference in the volume of right hepatic lobe between Child C group and Child B group, whereas the iodine storage of Child C group was lower than that of Child B group (P < 0.05). The volume and iodine storage of left lateral segment increased with the progression of liver cirrhosis in the Child A and Child B groups (P < 0.05), whereas there was no statistical difference between the Child B and Child C groups, and the iodine storage in the Child C group was lower than that of the Child B group (P < 0.05). The radiation dose of dual-energy scanning was lower than that of single-energy scanning (P < 0.001). The iodine concentration 1.512 mg/mL on the left medial segment reached the most optimal evaluation on cirrhosis, with a sensitivity of 100%, specificity of 0.722, and area under the curve of 0.914.

Conclusions
Iodine concentration in portal phase measurement can evaluate and reflect the severity of cirrhosis. Iodine content segmental quantification can analyze the changes of the liver storage with a progression of cirrhosis. Dual-energy scanning reduced the radiation damage in patients and is valuable for a further study and clinical application.