Rosenkrantz Andrew B, Koesters Thomas, Vahle Anne-Kristin, Friedman Kent, Bartlett Rachel M, Taneja Samir S, Ding Yu-Shin, Logan Jean
From the *Department of Radiology, and †Division of Urologic Oncology, Department of Urology, NYU Langone Medical Center, New York, NY.
Clin Nucl Med. 2015 Apr;40(4):e236-40. doi: 10.1097/RLU.0000000000000673.
Dynamic FDG imaging for prostate cancer characterization is limited by generally small size and low uptake in prostate tumors. Our aim in this pilot study was to explore feasibility of simultaneous PET/MRI to guide localization of prostate lesions for dynamic FDG analysis using a graphical approach.
Three patients with biopsy-proven prostate cancer underwent simultaneous FDG PET/MRI, incorporating dynamic prostate imaging. Histology and multiparametric MRI findings were used to localize tumors, which in turn guided identification of tumors on FDG images. Regions of interest were manually placed on tumor and benign prostate tissue. Blood activity was extracted from a region of interest placed on the femoral artery on PET images. FDG data were analyzed by graphical analysis using the influx constant Ki (Patlak analysis) when FDG binding seemed irreversible and distribution volume VT (reversible graphical analysis) when FDG binding seemed reversible given the presence of washout.
Given inherent coregistration, simultaneous acquisition facilitated use of MRI data to localize small lesions on PET and subsequent graphical analysis in all cases. In 2 cases with irreversible binding, tumor had higher Ki than benign using Patlak analysis (0.023 vs 0.006 and 0.019 vs 0.008 mL/cm3 per minute). In 1 case appearing reversible, tumor had higher VT than benign using reversible graphical analysis (0.68 vs 0.52 mL/cm3).
Simultaneous PET/MRI allows localization of small prostate tumors for dynamic PET analysis. By taking advantage of inclusion of the femoral arteries in the FOV, we applied advanced PET data analysis methods beyond conventional static measures and without blood sampling.
用于前列腺癌特征描述的动态氟代脱氧葡萄糖（FDG）成像受前列腺肿瘤通常体积小和摄取低的限制。我们这项初步研究的目的是探讨同时进行正电子发射断层扫描/磁共振成像（PET/MRI）以使用图形方法指导前列腺病变定位进行动态FDG分析的可行性。
三名经活检证实为前列腺癌的患者接受了同时进行的FDG PET/MRI检查，包括动态前列腺成像。组织学和多参数MRI结果用于定位肿瘤，进而指导在FDG图像上识别肿瘤。在肿瘤和良性前列腺组织上手动放置感兴趣区域。从PET图像上放置在股动脉上的感兴趣区域提取血液活性。当FDG结合似乎不可逆时，通过使用流入常数Ki（Patlak分析）的图形分析来分析FDG数据；当考虑到有洗脱现象FDG结合似乎可逆时，使用分布容积VT（可逆图形分析）。
鉴于固有的配准，同时采集便于在所有病例中使用MRI数据在PET上定位小病变并进行后续图形分析。在2例具有不可逆结合的病例中，使用Patlak分析，肿瘤的Ki高于良性组织（分别为0.023对0.006以及0.019对0.008 mL/cm³每分钟）。在1例表现为可逆的病例中，使用可逆图形分析，肿瘤的VT高于良性组织（0.68对0.52 mL/cm³）。
同时进行的PET/MRI能够定位小的前列腺肿瘤以进行动态PET分析。通过利用将股动脉纳入视野范围，我们应用了超越传统静态测量且无需采血的先进PET数据分析方法。
