Arimoto Maya K, Higashi Tatsuya, Nishii Ryuichi, Kagawa Shinya, Takahashi Masaaki, Kishibe Yoshihiko, Yamauchi Hiroshi, Ishitoya Satoshi, Oonishi Hiroyuki, Nakamoto Yuji, Togashi Kaori
Shiga Medical Center Research Institute, 5-4-30 Moriyama, Moriyama, Shiga, 524-8524, Japan.
Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University, Graduate School of Medicine, 54, Shogoin Kawahara-cho, Sakyo-ku, Kyoto, Kyoto, 606-8507, Japan.
Ann Nucl Med. 2016 Oct;30(8):553-62. doi: 10.1007/s12149-016-1098-3. Epub 2016 Jun 21.
α-N-methyl-(11)C-methylaminoisobutyric acid ((11)C-MeAIB) is a selective substrate of system A amino acid transport, and known to accumulate in malignant lesions. The aim of this study was to evaluate the utility of MeAIB PET for the assessment of prostate cancer, compared with FDG PET.
Thirty-four men (age range 57-77 years) with prostate cancer were prospectively enrolled, and underwent MeAIB PET and FDG PET between January 2011 and January 2013. MeAIB PET and FDG PET were performed at 20 and 50 min post-injection, respectively. SUVmax of the prostate was calculated, and visual analysis was conducted for MeAIB and FDG PET studies. MRI images were visually evaluated if available. All patients received total prostatectomy subsequently, and imaging findings were compared with pathological results, including T stage, Gleason score, and tumor size. The patient-based and lesion-based sensitivity and specificity were calculated according to pathological significant cancer.
Mean value of SUVmax of (11)C-MeAIB PET and (18)F-FDG PET in prostate cancer were 3.18 (±1.90, range; 1.55-9.57) and 3.88 (±2.85, range; 2.04-14.47). MeAIB PET and FDG PET were positive by visual analysis in 47.1 % (16/34) and 44.1 % (15/34) of the patients. MRI was positive in 51.5 % (17/33). Pathological stage and Gleason score were as follows: Stage 2 (n = 23), 3 (n = 8), and 4 (n = 3); Gleason score 6 (n = 13), 7 (n = 16), 8 (n = 3), and 9 (n = 2). The sensitivities tended to be higher according to higher pathological T stage or Gleason sum score for both MeAIB and FDG PET studies. Visual analysis of both MeAIB PET and FDG PET had significant correlation with extraprostatic extension (p < 0.05). MeAIB PET and FDG PET had complementary results by visual analysis in the assessment of prostate cancer. The patient-based sensitivity of MeAIB PET, FDG PET, and MRI were 51.6, 48.4, and 56.7 %, respectively. The patient-based specificity of these modalities was 100 % for each modality.
MeAIB PET has better diagnostic results than FDG PET for the assessment of significant prostate cancer, and these PET studies showed complementary results. MRI has even better diagnostic results than (11)C-MeAIB PET. MeAIB accumulates in prostate cancer, which indicates that the system A amino acid transport pathway is activated in prostate cancer.
α-N-甲基-（11）C-甲基氨基异丁酸（（11）C-MeAIB）是A系统氨基酸转运的选择性底物，已知其在恶性病变中会蓄积。本研究的目的是评估MeAIB PET与FDG PET相比在前列腺癌评估中的效用。
前瞻性纳入34例前列腺癌男性患者（年龄范围57 - 77岁），于2011年1月至2013年1月期间接受MeAIB PET和FDG PET检查。MeAIB PET和FDG PET分别在注射后20分钟和50分钟进行。计算前列腺的SUVmax，并对MeAIB和FDG PET检查进行视觉分析。如有可用的MRI图像，则进行视觉评估。所有患者随后均接受了前列腺全切术，并将影像学检查结果与病理结果进行比较，包括T分期、Gleason评分和肿瘤大小。根据病理显著癌计算基于患者和基于病灶的敏感性和特异性。
前列腺癌中（11）C-MeAIB PET和（18）F-FDG PET的SUVmax平均值分别为3.18（±1.90，范围：1.55 - 9.57）和3.88（±2.85，范围：2.04 - 14.47）。通过视觉分析，MeAIB PET和FDG PET在47.1%（16/34）和44.1%（15/34）的患者中呈阳性。MRI在51.5%（17/33）的患者中呈阳性。病理分期和Gleason评分如下：2期（n = 23）、3期（n = 8）和4期（n = 3）；Gleason评分6分（n = 13）、7分（n = 16）、8分（n = 3）和9分（n = 2）。对于MeAIB和FDG PET检查，根据更高的病理T分期或Gleason总分，敏感性往往更高。MeAIB PET和FDG PET的视觉分析与前列腺外侵犯均有显著相关性（p < 0.05）。在前列腺癌评估中，MeAIB PET和FDG PET通过视觉分析有互补结果。基于患者的MeAIB PET、FDG PET和MRI的敏感性分别为51.6%、48.4%和56.7%。这些检查方法基于患者的特异性均为100%。
在评估显著前列腺癌方面，MeAIB PET比FDG PET有更好的诊断结果，且这些PET检查显示出互补结果。MRI的诊断结果甚至优于（11）C-MeAIB PET。MeAIB在前列腺癌中蓄积，这表明A系统氨基酸转运途径在前列腺癌中被激活。
