Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, 54 Shogoinkawahara-cho, Sakyo-Ku, Kyoto 606-8507, Japan.
Eur J Nucl Med Mol Imaging. 2013 May;40(5):708-15. doi: 10.1007/s00259-012-2333-3. Epub 2013 Jan 23.
PET/CT using FDG has been widely used for the imaging of various malignant tumours, including plasma cell malignancy (PCM), but (11)C-methionine (MET), as a radiolabelled amino acid tracer, may also be useful because PCM is able to activate protein synthesis. The purpose of this study was to evaluate the clinical value of PET/CT imaging using MET in PCM, including multiple myeloma, compared with that of FDG PET/CT.
The study group comprised 20 patients with histologically proven PCM who underwent FDG PET/CT and MET PET/CT scans before (n = 6) or after (n = 14) treatment. Semiquantitative analysis was performed on a lesion basis. We also visually evaluated the scans qualitatively using a five-point scale (0, negative; 1, probably negative; 2, equivocal; 3, probably positive; 4, positive) on a lesion and a patient basis. The results were compared between the two scans.
Active PCM was confirmed in 15 patients, including two patients with extramedullary lesions. Uptake of MET tended to be higher (maximum standardized uptake value 10.3 ± 5.6, mean ± SD) than that of FDG (3.4 ± 2.7, p < 0.001), and more lesions of grade 3 or 4 were depicted by MET (MET 156 lesions vs. FDG 58 lesions). On a patient basis, two patients were accurately diagnosed only by MET. In the remaining 18 patients, consistent results were obtained, but potential upgrade of staging or restaging was necessary in 6 of 11 positive patients because more abnormal lesions were demonstrated by MET. The patient-based sensitivity, specificity and accuracy of MET for restaging were 89 %, 100 % and 93 %, respectively, while those of FDG were 78 %, 100 % and 86 %, respectively.
MET revealed an equal or greater number of lesions in PCM than FDG. MET may be especially useful when negative or inconclusive findings are obtained by FDG despite highly suspicious indications of recurrence.
正电子发射断层扫描（PET）/CT 联合氟代脱氧葡萄糖（FDG）已广泛用于多种恶性肿瘤的成像，包括浆细胞瘤（PCM），但作为放射性氨基酸示踪剂的（11）C-蛋氨酸（MET）可能也有用，因为 PCM 能够激活蛋白质合成。本研究旨在评估 MET PET/CT 成像在包括多发性骨髓瘤在内的 PCM 中的临床价值，并与 FDG PET/CT 进行比较。
研究组纳入了 20 例经组织学证实的 PCM 患者，这些患者在（n = 6）治疗前或（n = 14）治疗后分别接受了 FDG PET/CT 和 MET PET/CT 扫描。对病变进行半定量分析。我们还使用病变和患者的五分制（0，阴性；1，可能阴性；2，不确定；3，可能阳性；4，阳性）对扫描进行定性评估。比较两种扫描的结果。
15 例患者证实为活动性 PCM，包括 2 例髓外病变。MET 的摄取量似乎更高（最大标准化摄取值 10.3 ± 5.6，均值 ± 标准差），而 FDG 的摄取量较低（3.4 ± 2.7，p < 0.001），并且 MET 显示了更多的 3 级或 4 级病变（MET 156 个病变 vs. FDG 58 个病变）。基于患者，仅通过 MET 准确诊断了 2 例患者。在其余 18 例患者中，两种扫描的结果一致，但在 11 例阳性患者中有 6 例需要进行分期升级或重新分期，因为 MET 显示出更多的异常病变。MET 对重新分期的患者基于的敏感性、特异性和准确性分别为 89%、100%和 93%，而 FDG 的相应数值分别为 78%、100%和 86%。
MET 显示出与 FDG 相同或更多的 PCM 病变。当 FDG 尽管高度怀疑复发，但结果为阴性或不确定时，MET 可能特别有用。
