Lim Hyun Kyung, Kim Jeong Kon, Kim Kyung Ah, Cho Kyoung-Sik
Department of Radiology, Asan Medical Center, University of Ulsan, 388-1 Poongnap-dong, Songpa-gu, Seoul, 138-736, South Korea.
Radiology. 2009 Jan;250(1):145-51. doi: 10.1148/radiol.2501080207. Epub 2008 Nov 18.
To retrospectively assess the incremental value of an apparent diffusion coefficient (ADC) map combined with T2-weighted magnetic resonance (MR) images compared with T2-weighted images alone for prostate cancer detection by using a pathologic map as the reference standard.
This retrospective study was approved by the institutional review board; informed consent was waived. The study included 52 patients (mean age, 65 years +/- 5 [standard deviation]; range, 48-76 years) who underwent endorectal MR imaging and step-section histologic examination. Three readers with varying experience levels reviewed T2-weighted images alone, the ADC map alone, and T2-weighted images and ADC maps. The prostate was divided into 12 segments. The probability of prostate cancer in each segment on MR images was recorded with a five-point scale. Areas under the receiver operating characteristic curve (AUCs) were compared by using the Z test; sensitivity and specificity were determined with the Z test after adjusting for data clustering.
AUC of T2-weighted and ADC data (reader 1, 0.90; reader 2, 0.88; reader 3, 0.76) was greater than that of T2-weighted images (reader 1, 0.79; reader 2, 0.75; reader 3, 0.66) for all readers (P < .0001 in all comparisons). AUC of T2-weighted and ADC data was greater for readers 1 and 2 than for reader 3 (P < .001). Sensitivity of T2-weighted and ADC data (reader 1, 88%; reader 2, 81%; and reader 3, 78%) was greater than that of T2-weighted images (reader 1, 74%; reader 2, 67%; reader 3, 67%) for all readers (P = .01 for reader 1; P = .02 for readers 2 and 3). Specificity of T2-weighted and ADC data was greater than that of T2-weighted images for reader 1 (88% vs 79%, P = .03) and reader 2 (89% vs 77%, P < .001).
The addition of an ADC map to T2-weighted images can improve the diagnostic performance of MR imaging in prostate cancer detection.
以病理图谱作为参考标准，回顾性评估表观扩散系数（ADC）图联合T2加权磁共振（MR）图像相较于单纯T2加权图像在前列腺癌检测中的增量价值。
本回顾性研究经机构审查委员会批准；豁免知情同意。研究纳入52例患者（平均年龄65岁±5[标准差]；范围48 - 76岁），这些患者均接受了直肠内MR成像及连续切片组织学检查。三位经验水平不同的阅片者分别单独阅T2加权图像、单独阅ADC图以及同时阅T2加权图像和ADC图。前列腺被分为12个节段。用五点量表记录MR图像上每个节段前列腺癌的概率。采用Z检验比较受试者操作特征曲线下面积（AUC）；在对数据聚类进行校正后，用Z检验确定敏感性和特异性。
对于所有阅片者，T2加权图像与ADC数据的AUC（阅片者1为0.90；阅片者2为0.88；阅片者3为0.76）均大于单纯T2加权图像的AUC（阅片者1为0.79；阅片者2为0.75；阅片者3为0.66）（所有比较中P <.0001）。阅片者1和2的T2加权图像与ADC数据的AUC大于阅片者3（P <.001）。对于所有阅片者，T2加权图像与ADC数据的敏感性（阅片者1为88%；阅片者2为81%；阅片者3为78%）均大于单纯T2加权图像的敏感性（阅片者1为74%；阅片者2为67%；阅片者3为67%）（阅片者1，P =.01；阅片者2和3，P =.02）。阅片者1（88%对79%，P =.03）和阅片者2（89%对77%，P <.001）的T2加权图像与ADC数据的特异性大于单纯T2加权图像的特异性。
在T2加权图像上增加ADC图可提高MR成像在前列腺癌检测中的诊断性能。
