大范围扩散加权成像与骨扫描对照评价前列腺癌骨转移的前瞻性研究

Prospective study of bone metastasis from prostate cancer： comparison between large field diffusionweighted imaging and bone scintigraphy

目的评价大范围（从头顶到小腿）MR DWI在前列腺癌骨转移瘤检测中的应用。方法搜集接受前列腺MR检查的166例连续患者，所有患者均行前列腺局部扫描及大范围DWI。其中49例在1个月内接受骨扫描检查和大范围DWI并行双盲法诊断。以常规T1WI和压脂T2WI为标准，确定骨转移瘤的存在及其位置。49例均为MRI和核素检查后获得前列腺的穿刺病理结果。大范围DWI与骨扫描对骨转移瘤诊断的敏感度、特异度、受试者操作特征曲线（ROC曲线）下面积应用McNemar检验进行比较。转移瘤患者中有5例有〉10处／例的全身多发骨转移，在以病灶为单位研究时不纳入计算。结果49例中10例有骨转移瘤，而DWI和核素骨扫描分别诊断15和17例有骨转移瘤，大范围DWI和核素骨扫描诊断骨转移瘤的敏感度均为100％（10／10），特异性分别为87．2％（34／39）和82．1％（32／39），ROC曲线下面积分别为0．936和0．910。44例患者中2种技术共显示68处异常信号和（或）放射浓聚灶，有20处被证实为骨转移瘤，而DWI显示其中23处为骨转移瘤，核素骨扫描显示其中34处为骨转移瘤。以病灶为单位（68处）计算大范围DWI和核素骨扫描诊断骨转移瘤灶的敏感度均为90．0％（18／20），特异度分别为89．6％（43／48）和66．7％（32／48），ROC曲线下面积分别为0．898和0．783，大范围DWI的特异度高于骨扫描（P〈0．01），ROC曲线下面积也高于核素骨扫描（P〈0．05）。结论大范围DWI可用于前列腺癌骨转移瘤的检查，特异度和准确度高于骨扫描。

Objective To evaluate the large field diffusion weighted imaging （DWI） （from head vertex to lower leg） in detection of bone metastases from prostate cancer. Methods One hundred and sixty-six consecutive patients who were suspected of prostate cancer received pelvic MRI and large field diffusion weighted imaging examination. Forty-nine of them underwent bone seintigraphy within one month of the examination of large field DWI. The images were double-blindly evaluated without the knowledge of the pathology result. Conventional MR T1 and fat saturation T2 weighted images were taken as standard for the diagnosis of bone metastasis. The sensitivity, specificity, and area under curve between large field DWI and bone seintigraphy were compared with McNemar test. Five patients with bone metastases exceeding 10 per patient were excluded in the lesion-by-lesion analysis. Results Ten of the 49 patients were diagnosed as bone metastases. The diagnosis of bone metastasis were made in 15 patients by large field DWI and in 17 patients by bone seintigraphy. With patient number as study units （n = 49）, the diagnostic sensitivity of bone metastases with large field DWI and bone metastases were both 100% （10/10） , and specificity were 87.2% （34/39） vs. 82. 1% （32/39）, respectively. ROC study showed the area under curve （AUC） of large field DWI and bone scintigraphy were 0. 936 vs. 0. 910, respectively. Totally 68 abnormal foci were identified from large field DWI and/or bone scintigraphy in 44 patients （while 5 patients with bone metastases exceeding 10 foci per patient were excluded）, 20 of them were diagnosed as foci of bone metastasis. The diagnosis of bone metastases was made in 23 foci by large field DWI and in 34 by bone scintigraphy. With lesion numbers as study units （ n = 68 ）, the diagnostic sensitivity of large field DWI and bone scintigraphy were both 90. 0% （ 18/20）, and specificity were 89. 6% （43/48） vs. 66. 7% （32/48）, respectively. ROC study showed the area under curve of large field DWI and bone seintigraphy were 0. 898 vs. 0. 783, respectively. The difference of specificity between large field DWI and bone scintigraphy showed statistical significant difference （P 〈 0. 01 ）. The AUC between large field DWI and bone scintigraphy showed statistical significant difference （ P 〈 0. 05）. Conclusion Large field DWI may allow us to screen for bone metastasis in patients with prostate cancer, and its diagnostic specificity and accuracy may be higher than thai of bone scintigraphy.