磁共振T_2WI和波谱成像对前列腺癌诊断价值的比较研究

Comparison of T_2-weighted imaging and proton magnetic resonance spectroscopic imaging on prostate cancer detection

目的通过对分别应用T2加权成像(T2WI)、磁共振波谱成像(MRS)两种成像方法及其综合应用对前列腺癌进行定性诊断的比较,以病理结果为参照,探讨两种方法各自及综合应用对前列腺癌的诊断价值。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扫描及磁共振波谱(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将所得结果与病理结果对照。利用SPSS11.5软件对3种方法各自所得数据以及2种方法综合评分分别做受试者操作特性(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;MRS诊断:84.3﹪、98.0﹪和0.961±0.016,最佳界值为5;MRS结合T2WI诊断:92.2﹪,94.5﹪和0.971±0.011,最佳界值为4。结论通过独立评估T2WI及MRS2种方法均可以有效诊断前列腺癌。两种成像方法结合诊断前列腺癌的准确性显著高于2种成像技术独立诊断,其诊断结果与病理分析一致性较好。

Objective To compare the efficiency of T2-weighted imaging （TEWI） alone, MR spectroscopy （MRS） alone, and the combination of these two MR techniques in the diagnosis of prostate cancer, using pathologic findings as gold standard. Methods MR imaging, including TEWI and MRS, was performed at 1.5T with a body coil combined with a spine coil in 42 cases. Diagnosis was confirmed by pathologcal findings from transrectal prostate biopsy. All cases were evaluated by TEWI, MRS and then by the two methods combined. The statistical indicators and the receiver operating characteristic （ROC） curve analysis of each method were compared to the pathological findings. Results Among 42 cases 15 were pathologically confirmed to be cancerous, and 27 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, when the cutoffwas 3; 84.3 % and 98.0 % for MRS, when the cutoffwas 5; and 92.2 % and 94.5 % for the combined TEWI ＋ MRS, when the cutoff was 4. In the ROC analysis, the correlative areas under the ROC curves （Az） were 0.848 ± 0.030, 0.961 ± 0.016 and 0.971 ± 0.011 for TEWI, MRS, and the combination OfTEWI ＋ MRS, respectively. Conclusion Prostate cancer can be diagnosed effectively by T2WI or MRS alone. The accuracy of the detection of prostate cancer is increased through a combination of the two techniques.