磁共振DWI及动态增强扫描在前列腺疾病诊断中的价值

目的探讨磁共振扩散加权成像(DWI)和动态增强扫描(DCE-MRI)在前列腺疾病中的诊断价值。方法经穿刺活检或手术病理证实的20例前列腺癌及31例前列腺增生(BPH)患者进行了MR常规扫描、DWI和DCE-MRI扫描,测量病变的表观扩散系数(ADC)值,观察病灶常规MRI、DWI和动态增强MRI特征,绘制信号强度-时间曲线(SI-T曲线),SI-T曲线分成3型:Ⅰ型为信号强度早期增高后仍持续增高;Ⅱ型为信号强度早期增高后出现平台期;Ⅲ型为信号强度早期增高后出现下降期。经方差分析比较不同组织和病灶间差异。结果经DCE-MRI检查,20例前列腺癌患者中17例病灶区呈Ⅲ型曲线,2例呈Ⅱ型曲线,1例呈Ⅰ型曲线;31例前列腺增生患者中26例呈Ⅰ型曲线,4例呈Ⅱ型曲线,1例呈Ⅲ型曲线。前列腺癌组与BPH组的SI-T曲线类型分布的差异有统计学意义(P<0.01)。20例前列腺癌病灶于DWI上为高信号,于ADC图上呈明显低信号,ADC值为(1.18±0.08)×10-3 mm2/s,未被癌组织侵及的外围叶于DWI、ADC图上均呈等信号,ADC值为(2.67±0.09)×10-3 mm2/s;31例前列腺增生患者中央叶和外围叶于DWI、ADC图上均呈等信号,ADC值分别为(1.87±0.07)×10-3 mm2/s、(2.64±0.11)×10-3mm2/s。除前列腺增生的外围叶与未被癌组织侵及的外围叶之间差异无统计学意义(P>0.05)外,前列腺增生、前列腺癌、前列腺增生的外围叶和未被癌组织侵及的外围叶各组之间差异均有统计学意义(P<0.05)。DCE-MRI和DWI联合应用在前列腺癌诊断的敏感度、特异度和准确度均达80%以上。结论 DCE-MRI、DWI在前列腺癌和前列腺增生中具有特征性影像学表现,2种方法联合应用提高了MRI诊断前列腺癌的诊断和分期准确率。

Diagnostic value of dynamic contrast-enhanced MRI and diffusion-weighted MR imaging in prostate diseases

Objective To explore the applying value of the diagnosis of dynamic contrast-enhanced MRI（DCE-MRI） and diffusion weighted imaging （DWI） in prostate diseases. Methods 20 cases with prostate cancer （PC） and 31 cases with benign prostatic hyperplasia （BPH）, which were confirmed with biopsy-proven, operation and follow-up underwent the examinations of DCE-MRI and DWI. The ADC value was measured respectively on the lesions of Pc and BPH. The results of DCE MRI were evaluated by early-phase enhancement parameters and time-signal intensity curves （ST-T curves）. The curves were classified according to their shapes as type I , which had steady enhancement ; type Ⅱ , plateau of signal intensity; and typeⅢ , washout of signal intensity. The reskhs were statistically treated with ANOVA. Results Underwent the examination of DCE-MRI, the lesions SI-T curves of PC showed mainly type Ⅲ （17 cases） ; typeII could be seen in both PC （2 cases） and BPH （4 cases） ; type I most appeared in BPH （26 cases）. The distributions proved to have significant difference （ P 〈0.01）. The lesions were shown higher signal intensity on DWI but lower signal intensity on ADC map in 20 cases with PC, who were examined with DWI and the average ADC value was （1.18±0.08）× 10-3mm2/s. The peripheral zone uninvolved by cancer was shown homogeneous signal intensity on DWI and ADC, whose average ADC value of was （2.67±0.09）× 10-3mm2/s. In 31 cases with prostate hyperplasia, the mean ADC values of central gland and peripheral zone were （1.87±0.07）×10-3mm2/s and （2.64±0.11）×10-3mm2/s respectively. There were statistic significance between central gland of BPH, peripheral zone of BPH, cancerous lesions and peripheral zone uninvolved by cancer （ P 〈0.05） except peripheral zone of BPH and peripheral zone uninvolved by cancer in PC （ P 〈0.05）. The sensitivity, specificity and accuracy were more than 80% with the combining use of DCE-MRI and DWI. Conclusion DCE-MRI and DWI could present the specific findings in the diagnosis of PC BPH. The combining application of the two examination methods will further increase the accuracy in diagnosing and staging PC.