Liver Cancer
Copyright ©2007 Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Nov 21, 2007; 13(43): 5699-5706
Published online Nov 21, 2007. doi: 10.3748/wjg.v13.i43.5699
Characteristics and pathological mechanism on magnetic resonance diffusion-weighted imaging after chemoembolization in rabbit liver VX-2 tumor model
You-Hong Yuan, En-Hua Xiao, Jian-Bin Liu, Zhong He, Ke Jin, Cong Ma, Jun Xiang, Jian-Hua Xiao, Wei-Jian Chen
You-Hong Yuan, Jian-Bin Liu, Department of Radiology, Hunan Province People’s Hospital, Changsha 410005, Hunan Province, China
En-Hua Xiao, Zhong He, Cong Ma, Jun Xiang, Department of Radiology, the Second Xiang-Ya Hospital, Central South University, Changsha 410005, Hunan Province, China
Ke Jin, Wei-Jian Chen, Department of Pathology, Hunan Province Children’s Hospital, Changsha 410005, Hunan Province, China
Jian-Hua Xiao, Department of Epidemiology, Center for Disease Control of Hunan Province, Changsha 410005, Hunan Province, China
Author contributions: All authors contributed equally to the work.
Supported by the National Natural Science Foundation of China, No. 30070235, 30470508
Correspondence to: Dr. You-Hong Yuan, Department of Radiology, Hunan Province People’s Hospital, Changsha 410005, Hunan Province, China.
Telephone: +86-731-2278047 Fax: +86-731-2278011
Received: June 5, 2007
Revised: August 17, 2007
Accepted: October 2, 2007
Published online: November 21, 2007

AIM: To investigate dynamic characteristics and pathological mechanism of signal in rabbit VX-2 tumor model on diffusion-weighted imaging (DWI) after chemoembolization.

METHODS: Forty New Zealand rabbits were included in the study and forty-seven rabbit VX-2 tumor models were raised by implanting directly and intrahepatically after abdominal cavity opened. Forty VX-2 tumor models from them were divided into four groups. DWI was performed periodically and respectively for each group after chemoembolization. All VX-2 tumor samples of each group were studied by pathology. The distinction of VX-2 tumors on DWI was assessed by their apparent diffusion coefficient (ADC) values. The statistical significance between different time groups, different area groups or different b-value groups was calculated by using SPSS12.0 software.

RESULTS: Under b-value of 100 s/mm2, ADC values were lowest at 16 h after chemoembolization in area of VX-2 tumor periphery, central, and normal liver parenchyma around tumor, but turned to increase with further elongation of chemoembolization treatment. The distinction of ADC between different time groups was significant respectively (F = 7.325, P < 0.001; F = 2.496, P < 0.048; F = 6.856, P < 0.001). Cellular edema in the area of VX-2 tumor periphery or normal liver parenchyma around tumor, increased quickly in sixteen h after chemoembolization but, from the 16th h to the 48th h, cellular edema in the area of normal liver parenchyma around tumor decreased gradually and that in the area of VX-2 tumor periphery decreased lightly at, and then increased continually. After chemoembolization, Cellular necrosis in the area of VX-2 tumor periphery was more significantly high than that before chemoembolization. The areas of dead cells in VX-2 tumors manifested low signal and high ADC value, while the areas of viable cells manifested high signal and low ADC value.

CONCLUSION: DWI is able to detect and differentiate tumor necrotic areas from viable cellular areas before and after chemoembolization. ADC of normal liver parenchyma and VX-2 tumor are influenced by intracellular edema, tissue cellular death and microcirculation disturbance after chemoembolization.

Keywords: Liver, VX-2 tumor, Diffusion-weighted imaging, Apparent diffusion coefficient, Chemoembolization