Brief Article
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World J Gastroenterol. Mar 14, 2012; 18(10): 1130-1136
Published online Mar 14, 2012. doi: 10.3748/wjg.v18.i10.1130
Quantification of choline concentration following liver cell apoptosis using 1H magnetic resonance spectroscopy
Zhi-Wei Shen, Zhen Cao, Ke-Zeng You, Zhong-Xian Yang, Ye-Yu Xiao, Xiao-Fang Cheng, Yao-Wen Chen, Ren-Hua Wu
Zhi-Wei Shen, Zhen Cao, Ke-Zeng You, Zhong-Xian Yang, Ye-Yu Xiao, Xiao-Fang Cheng, Ren-Hua Wu, Department of Medical Imaging, The Second Affiliated Hospital, Shantou University Medical College, Shantou 515041, Guangdong Province, China
Yao-Wen Chen, Central Laboratory, Shantou University, Shantou 515041, Guangdong Province, China
Ren-Hua Wu, Provincial Key Laboratory of Medical Molecular Imaging, Shantou 515041, Guangdong Province, China
Author contributions: Shen ZW, Cao Z, Chen YW, Wu RH designed the research; Shen ZW, You KZ, Yang ZX and Xiao YY performed the research; You KZ did the pathological analysis; Shen ZW compared the MRS findings with the pathological reports; Shen ZW wrote the paper and Cheng XF revised the paper; Wu RH supervised the study and revised the paper.
Supported by Grants from Medical Scientific Research Foundation of Guangdong Province, China, No. B2008128; National Natural Science Foundation of China, No. 30930027 and No. 60971075, in part
Correspondence to: Ren-Hua Wu, MD, PhD, Professor, Department of Medical Imaging, The Second Affiliated Hospital, Shantou University Medical College, Shantou 515041, Guangdong Province, China. rhwu@stu.edu.cn
Telephone: +86-754-88915674 Fax: +86-754-88915674
Received: April 14, 2011
Revised: July 27, 2011
Accepted: October 14, 2011
Published online: March 14, 2012
Abstract

AIM: To evaluate the feasibility of quantifying liver choline concentrations in both normal and apoptotic rabbit livers in vivo, using 1H magnetic resonance spectroscopy (1H-MRS).

METHODS: 1H-MRS was performed in 18 rabbits using a 1.5T GE MR system with an eight-channel head/neck receiving coil. Fifteen rabbits were injected with sodium selenite at a dose of 10 μmol/kg to induce the liver cell apoptosis. Point-resolved spectroscopy sequence-localized spectra were obtained from 10 livers once before and once 24 h after sodium selenite injection in vivo. T1 and T2 relaxation time of water and choline was measured separately in the livers of three healthy rabbits and three selenite-treated rabbits. Hematoxylin and eosin and dUTP-biotin nick end labeling (TUNEL) staining was used to detect and confirm apoptosis. Choline peak areas were measured relative to unsuppressed water using LCModel. Relaxation attenuation was corrected using the average of T1 and T2 relaxation time. The choline concentration was quantified using a formula, which was tested by a phantom with a known concentration.

RESULTS: Apoptosis of hepatic cells was confirmed by TUNEL assay. In phantom experiment, the choline concentration (3.01 mmol/L), measured by 1H-MRS, was in good agreement with the actual concentration (3 mmol/L). The average T1 and T2 relaxation time of choline was 612 ± 15 ms and 74 ± 4 ms in the control group and 670 ± 27 ms and 78 ± 5 ms in apoptotic livers in vivo, respectively. Choline was quantified in 10 rabbits, once before and once after the injection with sodium selenite. The choline concentration decreased from 14.5 ± 7.57 mmol/L before sodium selenite injection to 10.8 ± 6.58 mmol/L (mean ± SD, n = 10) after treatment (Z = -2.395, P < 0.05, two-sample paired Wilcoxon test).

CONCLUSION: 1H-MRS can be used to quantify liver choline in vivo using unsuppressed water as an internal reference. Decreased liver choline concentrations are found in sodium selenite-treated rabbits undergoing liver cell apoptosis.

Keywords: Cell apoptosis; Magnetic resonance spectroscopy; Quantification; Choline; In vivo