前列腺癌的MRI诊断:T2WI、DWI、MRS及其综合应用

Prostate cancer detection:comparison of T2-weighted imaging,diffusion-weighted imaging,proton magnetic resonance spectroscopy,and the combination of three techniques

目的以病理结果为参照,探讨T2WI、DWI及MRS三种成像方法及其综合应用对前列腺癌定性诊断的价值。方法 42例患者在1.5T磁共振仪上采用体部矩阵线圈结合脊柱矩阵线圈行T2WI、DWI及3DCSI1H-MRS扫描,所有病例均经直肠穿刺活检证实。按照前列腺6分区法将所得图像数据分区评估测量,采用5分制针对各分区评分,并与病理结果对照。对三种扫描方法各自所得数据以及三种方法综合评分分别做ROC曲线分析比较,计算各组方法诊断的敏感性、特异性及准确性等。结果 42例病例中15例经穿刺证实为前列腺癌,27例为前列腺良性病变。252个分区均得到病理证实,其中201个为良性,51个为恶性。各组诊断方法的敏感性、特异性及ROC曲线下面积(Az)如下:T2WI:88.2%、67.2%和0.848±0.030,最佳诊断界值为3;DWI:82.4%、81.6%和0.860±0.033,最佳诊断界值为4;MRS:84.3%、98.0%和0.961±0.016,最佳诊断界值为5;三者综合:96.1%、96.5%和0.978±0.009,最佳诊断界值为4。结论 T2WI、DWI及MRS三种方法均可以独立有效诊断前列腺癌。三种成像方法结合诊断前列腺癌的准确性显著高于三种成像技术独立诊断,其诊断结果与病理分析一致性较好。在三种成像技术中,MRS的诊断价值较高。

Objective：To evaluate T2-weighted imaging （T2WI）,diffusion-weighted imaging （DWI）,MR spectroscopy （MRS）,and the combination of the three MR techniques in the diagnosis of prostate cancer,as correlation with histopathologic fi ndings.Materials and Methods：MR imaging,including T2WI,DWI,and MRS,was performed at 1.5 T MR scanner with a body coil combined with a spine coil in 42 cases.Diagnosis was confi rmed by histopathology through systematic transrectal prostate biopsy.All cases were evaluated by T2WI,DWI,MRS,and then by the three methods combined.The statistical indicators and the receiver operating characteristic （ROC） curve analysis of each method were compared to histopathological fi ndings obtained by transrectal prostate biopsy.Results：Fifteen of 42 cases were confi rmed to be cancerous,and 27 of 42 cases were noncancerous.All the 252 sextants were confirmed by biopsies,including 201 benign sextants and 51 malignant sextants.The sensitivity and the specificity for the detection of prostate cancer were 88.2% and 67.2% for T2WI,as the cutoff was 3;82.4% and 81.6% for DWI,as the cutoff was 4;84.3% and 98.0% for MRS,as the cutoff was 5;and 96.1% and 96.5% for the combined T2WI＋DWI＋MRS,as the cutoff was 4.In the ROC analysis,the correlative areas under the ROC curves （Az） were 0.848±0.030,0.860±0.033,and 0.961±0.016 for T2WI,DWI,and MRS,respectively,and 0.978±0.009 for the combination of T2WI＋DWI＋MRS.Conclusion：Prostate cancer can be diagnosed effectively by T2WI,DWI and MRS separately.The diagnostic accuracy of prostate cancer is increased through a combination of the three techniques.Moreover,MRS demonstrated higher accuracy comparing with T2WI or DWI.