Effect of b value on monitoring therapeutic response by diffusion-weighted imaging
Effect of b value on monitoring therapeutic response by diffusion-weighted imaging作者机构：Department of Radiology Affiliated Cancer Hospital of Fudan University Shanghai 200032 China Department of Oncology Shanghai Medical College Fudan University Shanghai 200032 China Department of Radiology Affiliated Changzheng Hospital of the Second Military Medical University Shanghai 200032 China Department of Radiology Affiliated Zhongshan Hospital of Fudan University Shanghai 200032 China Department of Pathology Affiliated Cancer Hospital of Fudan University Shanghai 200032 China
出 版 物：《World Journal of Gastroenterology》 (世界胃肠病学杂志（英文版）)
年 卷 期：2008年第14卷第38期
页 面：5893-5899页
核心收录：
学科分类：1002[医学-临床医学] 100214[医学-肿瘤学] 10[医学]
基 金：The National Natural Science Foundation of China, NO. 30470503 The Key Program of Shanghai Science and Technology Commission, NO. 04JC14074 The Foundation of Shanghai Educational commission, NO. 03J405037
主 题：Hepatic carcinoma Diffusion-weighted MR Treatment response Apparent diffusion coefficient
摘 要：AIM： To explore the diffusion gradient b-factor that optimizes both apparent diffusion coefficient （ADC） measurement and contrast-to-noise （CNR） for assessing tumor response to transarterial chemoembolization （TACE） in a rabbit model. METHODS： Twelve New Zealand white rabbits bearing VX2 tumors in the liver were treated with TACE. Diffusion-weighted imaging （DWI） with various b values was performed using the same protocol before and 3 d after treatment with TACE. ADC values and CNR of each tumor pre- and post-treatment with different b factors were analyzed. Correlation between ADC values and extent of necrosis in histological specimens was analyzed by a Pearson＇s correlation ***： The quality of diffusion-weighted images diminished as the b value increased. A substantial decrease in the mean lesion-to-liver CNR was observed on both pre- and post-treatment DW images, the largest difference in CNR pre- and post-treatment was manifested at a b value of 1000 s/mm^2 （P = 0.036 ）. The effect of therapy on diffusion early after treatment was shown by a significant increase in ADCs （P = 0.007）, especially with large b factors （≥ 600 s/mm^2）. The mean percentage of necrotic cells present within the tumor was 76.3%-97.5%. A significant positive correlation was found between ADC values and the extent of necrosis with all b values except for b200, a higher relative coefficient between ADC values and percentage of necrosis was found on DWI with bl000 and b2000 （P = 0.002 and 0.006, respectively）. CONCLUSION： An increasing b value of up to 600 s/mm^2 would increase ADC contrast pre- and post-treatment, but decrease image quality. Taking into account both CNR and ADC measurement, diffusion-weighted imaging obtained with a b value of 1000 s/mm^2 is recommended for monitoring early hepatic tumor response to TACE.
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