磁共振超高b值弥散序列指导前列腺穿刺的初步研究

Evaluation of ultra-high-b-value diffusion-weighted MR imaging in diagnosing prostate cancers:a preliminary study

目的探讨MR超高b值弥散序列指导前列腺穿刺的临床意义。方法前列腺穿刺病理证实患者共计48例,其中前列腺癌15例,前列腺增生33例。所有患者行MR常规扫描及弥散序列扫描,b=800,1500。以穿刺所得病理结果为金标准,分别观察前列腺癌及前列腺增生的常规b值及超高b值弥散图像特点。同时评价常规b值,超高b值及两组联合的诊断灵敏度、特异度、阳性预测值、阴性预测值。结果常规b值,超高b值及两组联合的诊断灵敏度分别为79.17%,62.5%,91.67%;特异度分别为75.61%,95.12%,95.12%;阳性预测分别为60%,88.24%,91.67%;阴性预测值分别为86.11%,81.25%,95.12%。前列腺癌在超高b值图像上呈高信号,具有明显的特征,在常规b值图像上前列腺癌及前列腺增生均可呈等信号或高信号影。在诊断效能方面,超高b值联合常规b值对比2种单独引导具有明显优越性。结论趟高b值弥散序列有助于前列腺癌的诊断,尤其在联合常规b值的情况下,明显提高诊断效能。

Objective To evaluate the ultra-high-b-value diffusion-weighted imaging in diagnosing prostate cancers. Methods A total of 48 patients with pathologically confirmed prostate lesions were enrolled in this study. The lesions included prostate cancer （n = 15） and benign prostate hyperplasia （n = 33）. Before biopsy, both conventional MR diffusion sequence scanning and ultra- high- b-value （n = 800,1500） sequence scanning were performed in all patients. Taking the biopsy results as the gold standard, the imaging characteristics on conventional MRI and on ultra-high-b-value MRI of the prostate cancer as well as the benign prostate hyperplasia were evaluated. The diagnostic sensitivity, specificity, positive predictive value and negative predictive value were determined when the conventional MRI and ultra-high-b-value MRI were used together in making diagnosis. Results The diagnostic sensitivity of conventional b-value imaging, ultra-high-b-value imaging and combination use of conventional b-value and ultra-high-b-value imaging was 79.17%, 62.5% and 91.67%, respectively. While the specificity was 75.61%, 95.12% and 95.12% , respectively; the positive predictive value was 60%, 88.24% and 91.67%, respectively; the negative predic tive value was 86.11%, 81.25% and 95.12%, respectively. On ultra-high-b-value images, the prostate cancer assumed hyperintense signal, which was very characteristic. On conventional b-value images, both the prostate cancer and the benign prostate hyperplasia were manifested as isointense or hyperintense signals. In makingdiagnosis of prostate lesions, the combination use of conventional b-value and uhra-high-b-value imaging was superior to simple use of conventional b-value or ultra- high- b- value imaging. Conclusion Ultra- high - b - value diffusion - weighted sequenceimaging is very useful in diagnosing prostate cancers. The diagnostic accuracy can be significantly improved when conventional b-value sequence imaging is employed together.