前列腺和精囊磁共振扩散成像中EPI与SSFSE序列的比较

目的比较回波平面成像（EPI）与单次激发快速自旋回波（SSFSE）扩散成像序列测量前列腺和精囊的表观扩散系数（ADC）值. 资料与方法选择40例无前列腺和精囊疾病的男性,使用EPI和SSFSE扩散成像序列,行前列腺和精囊局部的磁共振扩散成像检查.两种脉冲序列的扩散敏感梯度（b）值均取1 000s/mm2.在工作站上测量前列腺中央带和外周带、精囊、膀胱、盆腔脂肪、直肠内气体的ADC值.对两种脉冲序列测得的组织ADC值使用配对t检验进行比较. 结果 EPI序列40名受检者中32例（80%）获得可测量ADC值的图像,SSFSE序列40例（100%）获得可测量ADC值的图像.两种扩散成像序列测得的膀胱、直肠内气体和盆腔脂肪的ADC值无统计学差异（P〉0.05）,而两种扩散成像序列测得的前列腺中央带、外周带、精囊的ADC值有统计学差异（P〈0.01）.EPI序列测得上述组织的ADC值较小. 结论不同扩散成像序列测得的前列腺中央带、外周带和精囊的ADC值有差异.

Diffusion MR Imaging of Seminal Vesicle and Prostate Gland: Comparison of ADCs Obtained from Echo-Planar Sequence and Single Shot Fast Spin Echo Sequence

Objective To evaluate whether there was any difference between the apparent diffusion coefficients(ADCs) calculated from Echo-Planar Sequence and Single Shot Fast Spin Echo Sequence.Materials and Methods Diffusion echo-planar imaging(EPI) sequence and single shot fast spin echo(SSFSE) sequence were performed with a 1.5T MR unit in 40 male patients without prostate and seminal vesicle diseases.Then images were obtained with a diffusion factor(b) using 1000sec/mm2, and ADC maps were constructed using EPI and SSFSE sequences in central and peripheral zone of prostate,seminal vesicle,bladder,pelvic fat and gas in the rectum,the results were compared statistically.Results Acceptable images for ADC measurement were obtained in 32(80%) cases of EPI sequence and 40(100%) were acceptable of SSFSE sequence.There was no statistically difference of the mean ADC of bladder,gas in the rectum and pelvic fat between the two sequences(P>0.05).Whereas there was statistically difference of the mean ADC of seminal vesicle,the central zone and peripheral zone of prostate gland between the two sequences(P<0.01).The ADC value obtained by the SSFSE sequence was significantly higher than that obtained by EPI sequence.Conclusion ADCs of seminal vesicle and prostate gland measured with different sequence may be different,even though theb value is identical.