Department of Radiology, Radboud University Nijmegen Medical Centre, Geert Grooteplein 10, 6525GA Nijmegen, the Netherlands.
Radiology. 2012 Nov;265(2):457-67. doi: 10.1148/radiol.12111744. Epub 2012 Jul 27.
To determine the individual and combined performance of magnetic resonance (MR) spectroscopic imaging and diffusion-weighted (DW) imaging at 3 T in the in vivo assessment of prostate cancer aggressiveness by using histopathologically defined regions of interest on radical prostatectomy specimens to define the prostate cancer regions to be investigated.
The local institutional ethics review board approved this retrospective study and waived the informed consent requirement. Fifty-four patients with biopsy-proved prostate cancer underwent clinical MR spectroscopic imaging followed by prostatectomy. Guided by the histopathologic map, all spectroscopy voxels that contained tumor tissue were selected, and metabolite ratios (choline [Cho] plus creatine [Cr]-to-citrate [Cit] and Cho/Cr ratios) were derived. For each spectroscopic voxel, 25th percentile apparent diffusion coefficient (ADC) of the region corresponding to that voxel was determined, representing the most aberrant tumor part on the ADC map, which was often smaller than spectroscopic imaging voxels. Maximum metabolic ratios and minimum 25th percentile ADC of each tumor were related to tumor aggressiveness and were used to differentiate aggressiveness classes. A logistic regression model (LRM) was used to combine data from both modalities.
Significant correlation was found between aggressiveness classes and maximum Cho+Cr/Cit ratio (ρ=0.36), maximum Cho/Cr ratio (ρ=0.35), and minimum 25th percentile ADC (ρ=-0.63) in the peripheral zone (PZ). In the transition zone (TZ), the correlation was significant for only Cho+Cr/Cit and Cho/Cr ratios (ρ=0.58 and ρ=0.60, respectively). For differentiation between aggressiveness classes, LRM use did not result in significantly improved differentiation over any individual variables.
These findings enabled confirmation that MR spectroscopic imaging and DW imaging offer potential for in vivo noninvasive assessment of prostate cancer aggressiveness, and both modalities have comparable performance. The combination did not result in better performance. Nonetheless, the better performances of metabolite ratios in the TZ and of ADCs in the PZ suggest that they have complementary value.
通过使用根治性前列腺切除术标本上的组织病理学定义的感兴趣区域来定义要研究的前列腺癌区域，确定磁共振（MR）波谱成像和扩散加权（DW）成像在 3T 体内评估前列腺癌侵袭性的单独和联合性能。
当地机构伦理审查委员会批准了这项回顾性研究，并豁免了知情同意要求。54 名经活检证实患有前列腺癌的患者接受了临床 MR 波谱成像检查，然后进行了前列腺切除术。根据组织病理学图谱，选择包含肿瘤组织的所有波谱体素，并得出代谢物比率（胆碱[Cho]+肌酸[Cr]-柠檬酸[Cit]和 Cho/Cr 比率）。对于每个波谱体素，确定与该体素相对应的区域的第 25 百分位表观扩散系数（ADC），代表 ADC 图谱上最异常的肿瘤部分，通常小于波谱成像体素。每个肿瘤的最大代谢比和最小第 25 百分位 ADC 与肿瘤侵袭性相关，并用于区分侵袭性类别。使用逻辑回归模型（LRM）结合两种模式的数据。
在外周区（PZ），侵袭性类别与最大 Cho+Cr/Cit 比率（ρ=0.36）、最大 Cho/Cr 比率（ρ=0.35）和最小第 25 百分位 ADC（ρ=-0.63）之间存在显著相关性。在过渡区（TZ），仅 Cho+Cr/Cit 和 Cho/Cr 比率具有显著相关性（ρ=0.58 和 ρ=0.60）。对于侵袭性类别之间的区分，LRM 的使用并未导致任何个体变量的区分能力显著提高。
这些发现证实了 MR 波谱成像和 DW 成像具有评估前列腺癌侵袭性的潜在能力，两种模式都具有相当的性能。组合并没有产生更好的性能。尽管如此，代谢物比率在 TZ 中的更好表现和 ADC 在 PZ 中的更好表现表明它们具有互补价值。
