Coakley Fergus V, Teh Hui Seong, Qayyum Aliya, Swanson Mark G, Lu Ying, Roach Mack, Pickett Barby, Shinohara Katsuto, Vigneron Daniel B, Kurhanewicz John
Department of Radiology, University of California San Francisco, 505 Parnassus Ave, Box 0628, M-372, San Francisco, CA 94143-0628, USA.
Radiology. 2004 Nov;233(2):441-8. doi: 10.1148/radiol.2332032086. Epub 2004 Sep 16.
To evaluate endorectal magnetic resonance (MR) imaging and MR spectroscopic imaging for the depiction of locally recurrent prostate cancer after external beam radiation therapy.
Endorectal MR imaging and MR spectroscopic imaging were performed in 21 patients with biochemical failure after external beam radiation therapy for prostate cancer. Two readers independently and retrospectively reviewed MR images and rated the likelihood of recurrent tumor on a five-point scale. Spectroscopic voxels were considered suspicious for malignancy if the choline level was elevated and citrate was absent. Receiver operating characteristic curve analysis was used to assess cancer detection in each side of the prostate with endorectal MR imaging and spectroscopic imaging at different thresholds based on the scores assigned by the two readers and on the number of suspicious voxels in each hemiprostate, respectively. The presence or absence of cancer at subsequent transrectal biopsy was used as the standard of reference.
Biopsy demonstrated locally recurrent prostate cancer in nine hemiprostates in six patients. The area under the receiver operating characteristic curve for the detection of locally recurrent cancer with MR imaging was 0.49 and 0.51 for readers 1 and 2, respectively. By using the number of suspicious voxels to define different diagnostic thresholds, the area under the receiver operating characteristic curve for MR spectroscopic imaging was significantly (P < .005) higher, at 0.81. In particular, the presence of three or more suspicious voxels in a hemiprostate showed a sensitivity and specificity of 89% and 82%, respectively, for the diagnosis of local recurrence. Seven hemiprostates demonstrated complete metabolic atrophy at spectroscopic imaging and only postirradiation atrophy at biopsy.
Preliminary data suggest that MR spectroscopic imaging, but not endorectal MR imaging, may be of value for the depiction of locally recurrent prostate cancer after radiation therapy.
评估直肠内磁共振（MR）成像和MR波谱成像在描绘前列腺癌外照射放疗后局部复发情况中的应用。
对21例前列腺癌外照射放疗后出现生化指标异常的患者进行直肠内MR成像和MR波谱成像检查。两名阅片者独立且回顾性地分析MR图像，并采用五点量表对肿瘤复发的可能性进行评分。若胆碱水平升高且枸橼酸盐缺失，则认为波谱成像体素可疑为恶性。基于两名阅片者给出的评分以及每个半侧前列腺中可疑体素的数量，分别采用不同阈值的直肠内MR成像和波谱成像，通过绘制受试者操作特征曲线分析来评估前列腺两侧的癌症检测情况。以随后经直肠活检中癌症的有无作为参考标准。
活检显示6例患者的9个半侧前列腺存在局部复发性前列腺癌。阅片者1和阅片者2通过MR成像检测局部复发性癌症的受试者操作特征曲线下面积分别为0.49和0.51。通过使用可疑体素数量定义不同诊断阈值，MR波谱成像的受试者操作特征曲线下面积显著更高（P <.005），为0.81。特别是，一个半侧前列腺中存在三个或更多可疑体素时，对局部复发诊断的敏感性和特异性分别为89%和82%。7个半侧前列腺在波谱成像中显示完全代谢性萎缩，而活检仅显示放疗后萎缩。
初步数据表明，MR波谱成像而非直肠内MR成像，可能在描绘放疗后局部复发性前列腺癌方面具有价值。
