Department of Radiology, Radboud University Nijmegen Medical Centre, 6500 HB Nijmegen, The Netherlands.
Invest Radiol. 2013 Oct;48(10):693-701. doi: 10.1097/RLI.0b013e31828eeaf9.
The objective of this study was to evaluate the apparent diffusion coefficient (ADC) of diffusion-weighted magnetic resonance (MR) imaging for the differentiation of transition zone cancer from non-cancerous transition zone with and without prostatitis and for the differentiation of transition zone cancer Gleason grade (GG) using MR-guided biopsy specimens as a reference standard.
From consecutive MR-guided prostate biopsies (2008-2012) in our referral center, we retrospectively included patients from whom diffusion-weighted MR imaging ADC values were acquired during MR-guided biopsy and whose biopsy cores had a (cancer) core length 10 mm or greater and originated from the transition zone. Two radiologists, who were blinded to the ADC data, annotated regions of interest on biopsy sampling locations of MR-guided biopsy confirmation scans in consensus. Median ADC (mADC) of the regions of interest was related to histopathology outcome in MR-guided biopsy core specimens. Mixed model analysis was used to evaluate mADC differences between 7 histopathology categories predefined as MR-guided biopsy core specimens with primary and secondary GG 4-5 (I), primary GG 4-5 secondary GG 2-3 (II), primary GG 2-3 secondary GG 4-5 (III) and primary and secondary GG 2-3 cancer (IV), and noncancerous tissue without (V) or with degree 1 (VI) or degree 2 prostatitis (VII). Diagnostic accuracy was evaluated using areas under the receiver operating characteristic (AUC) curve.
Fifty-two patients with 87 cancer-containing biopsy cores and 53 patients with 101 non-cancerous biopsy cores were included. Significant mean mADC differences were present between cancers (mean mADC, 0.77-0.86 × 10 mm/s) and noncancerous transition zone without (1.12 × 10 mm/s) and with degree 1 to 2 prostatitis (1.05-1.12 × 10 mm/s; P < 0.0001-0.05). Exceptions were mixed primary and secondary GG cancers versus a degree 2 of prostatitis (P = 0.06-0.09). No significant differences were found between subcategories of primary and secondary GG cancers (P = 0.17-0.91) and between a degree 1 and 2 prostatitis and non-cancerous transition zone without prostatitis (P = 0.48-0.94).The mADC had an AUC of 0.84 to differentiate cancer versus non-cancerous transition zone. AUCs of 0.84 and 0.56 were found for mADC to differentiate prostatitis from cancer and from non-cancerous transition zone. The mADC had an AUC of 0.62 to differentiate a primary GG 4 versus GG 3 cancer.
The mADC values can differentiate transition zone cancer from non-cancerous transition zone and from a degree 1, and from most cases of a degree 2 prostatitis. However, because of substantial overlap, mADC has a moderate accuracy to differentiate between different primary and secondary GG subcategories and cannot be used to differentiate non-cancerous transition zone from degrees 1 to 2 of prostatitis. Diffusion-weighted imaging ADC may therefore contribute in the detection of transition zone cancers; however, as a single functional MR imaging technique, diffusion-weighted imaging has a moderate diagnostic accuracy in separating higher from lower GG transition zone cancers and in differentiating prostatitis from non-cancerous transition zone.
本研究旨在评估磁共振（MR）扩散加权成像中的表观扩散系数（ADC）在区分伴有和不伴有前列腺炎的移行区癌与非癌移行区，以及使用 MR 引导活检标本作为参考标准区分移行区癌 Gleason 分级（GG）方面的作用。
在我们的转诊中心连续进行的 MR 引导前列腺活检（2008-2012 年）中，我们回顾性纳入了在 MR 引导活检期间采集了扩散加权 MR 成像 ADC 值且活检芯长度≥10mm且来自移行区的患者。两名放射科医生在共识中对 MR 引导活检确认扫描的活检采样位置进行了盲法 ROI 注释。活检标本的 ROI 中值 ADC（mADC）与 MR 引导活检中的组织病理学结果相关。采用混合模型分析评估了 7 种组织病理学类别之间的 mADC 差异，这些类别在 MR 引导活检核心标本中预先定义为原发性和继发性 GG 4-5（I）、原发性 GG 4-5 继发性 GG 2-3（II）、原发性 GG 2-3 继发性 GG 4-5（III）和原发性和继发性 GG 2-3 癌（IV）以及无癌组织（V）或有程度 1（VI）或程度 2 前列腺炎（VII）。使用受试者工作特征（ROC）曲线下面积（AUC）评估诊断准确性。
共纳入 52 例 87 个含有癌组织的活检芯和 53 例 101 个无癌组织的活检芯患者。癌症组织（mADC 平均值为 0.77-0.86×10mm/s）与无癌移行区（1.12×10mm/s）和有程度 1 至 2 前列腺炎（1.05-1.12×10mm/s）之间存在显著的平均 mADC 差异（P<0.0001-0.05）。混合原发性和继发性 GG 癌症与 2 度前列腺炎的情况除外（P=0.06-0.09）。原发性和继发性 GG 癌症的亚组之间（P=0.17-0.91）以及 1 度和 2 度前列腺炎与无前列腺炎的移行区之间（P=0.48-0.94）未发现显著差异。mADC 用于区分癌症与非癌移行区的 AUC 为 0.84。mADC 用于区分前列腺炎与癌症和非癌移行区的 AUC 分别为 0.84 和 0.56。mADC 用于区分原发性 GG 4 与 GG 3 癌症的 AUC 为 0.62。
mADC 值可区分移行区癌与非癌移行区和 1 度前列腺炎，与大多数 2 度前列腺炎也能区分。然而，由于重叠较大，mADC 对区分不同的原发性和继发性 GG 亚组的准确性中等，不能用于区分非癌移行区与 1 至 2 度前列腺炎。因此，扩散加权成像 ADC 可能有助于检测移行区癌；但是，作为单一的功能磁共振成像技术，扩散加权成像在区分高 GG 与低 GG 移行区癌以及区分前列腺炎与非癌移行区方面的诊断准确性中等。
