1.5T MR高b值DWI诊断早期前列腺癌的临床价值研究

The Clinical Application of 1.5 T MR High-b-Value Diffusion Weighted Imaging in Detecting Early Prostate Cancer

目的:寻找1.5T磁共振弥散成像在早期前列腺癌诊断的最佳b值。方法:回顾性分析我院305例前列腺MR检查资料,经手术病理证实的前列腺癌59例,其中早期前列腺癌36例,前列腺增生56例,前列腺炎8例。扫描序列采用T1WI、T2WI和DWI扫描,b值选用800 s/mm2 121例,b值同时选用1000s/mm2、1200 s/mm2、1500 s/mm2184例。测量DWI高信号区ADC值及观察ADC图。结果:27例外周腺体前列腺癌有1例误诊,而3例中央移行带前列腺增生误诊为前列腺癌,其中2例为b值选用800 s/mm2时,1例为选用高b值时,而有4例前列腺增生误诊为前列腺癌,其中3例为b值选用800 s/mm2时,1例为选用b值为1000 s/mm2时。结论:磁共振弥散加权成像选用不同的b值对早期前列腺疾病的准确率各不相同,总体说来1.5T MR DWI检查选用b值为1500 s/mm2诊断中央移行带前列腺癌的准确率高于其他b值;而良恶性ADC值临界点因b值的高低而不同,高b值者ADC值临界点低于低b值;且ADC值低者其Gleason分级分值高,呈负相关。

Purpose： To find the optimal b-value of 1.5 T MR diffusion weighted imaging（DWI） in the diagnosis of early prostate cancer. Methods： This paper analyzed 298 cases prostate MR data in our hospital, 59 cases of them were prostate cancer, which were confirmed by surgery and pathology results, 36 cases were early prostate cancer, and 56 cases prostate hyperplasia, 8 cases prostatitis. The MR sequences included T1 WI, T2 WI and DWI, 121 cases were scaned with the b-value of 800 s/mm^2, and 184 cases were scaned with the b-value of 1000 s/mm^2, 1200 s/mm^2, and 1500 s/mm^2. The ADC values of the high signal intensity region on DWI were measured, and ADC maps were observed. Results： One case was misdiagnosed in 27 cases of peripheral prostate cancer; 3 cases of central transitional zone prostate hyperplasia were misdiagnosed as prostate cancer, 2 cases of them were scanned with the b-value of 800 s/mm^2, the other one was scanned with the higher b-value; 4 cases of prostatic hyperplasia were misdiagnosed as prostate cancer, 3 cases of them were scanned with the b-value of 800 s/mm^2, the other one was scanned with the b-value of 1000 s/mm^2, Conclusion： The accuracy rate of early prostate disease was different when we chose the different b-value in MR diffusion weighted imaging. Overall, the accuracy rate of DWI with b-value of 1500s/mm^2 for diagnosis of central transitional zone prostate cancer was higher than that of DWI with other b-values in 1.5TMR. The cut-off ADC values for differentiating benign and malignant lesions were different owing to the difference of b-value, it was lower for high b-value than that for low b-value. When the lesion had low ADC value, their Gleason score were high, they were negatively correlated.