Lesion Analysis of F-Metafluorobenzylguanidine PET Imaging in Neuroblastoma.

A PET analog of metaiodobenzylguanidine (MIBG)-F-metafluorobenzylguanidine (F-MFBG)-allows for rapid same-day imaging. We previously reported on the safety and feasibility of F-MFBG PET imaging in patients with neuroendocrine tumors. We now report a comprehensive analysis of lesion detection with F-MFBG imaging in patients with neuroblastoma compared with I-MIBG imaging. We analyzed concurrent F-MFBG and I-MIBG scans in 37 patients (40 paired scans). Patients with relapsed or refractory neuroblastoma were included. Patients received 74.11-465.83 MBq (2.0-12.6 mCi) of F-MFBG intravenously, followed by imaging 60 min after injection. All patients had an I-MIBG scan within 4 wk of F-MFBG imaging without any intervening therapy. I-MIBG scans included whole-body planar and SPECT/CT of the chest, abdomen, and pelvis. All detected lesions were noted for each modality. I-MIBG and F-MFBG findings were evaluated for concordance and discordance. Modified Curie scores were assigned to both I-MIBG scans, equivalent scores were ascertained for F-MFBG imaging, and scores were then compared. All patients with a positive I-MIBG scan had positive F-MFBG imaging. In 2 patients, both I-MIBG and F-MFBG scans were negative. In 1 patient, the F-MFBG scan was positive, whereas the I-MIBG scan was negative. In 30 of 40 scans, F-MFBG showed more sites than did I-MIBG. Overall, more lesions were noted on the F-MFBG scans (mean, 18; range 0-61) compared with the I-MIBG scans (mean, 12; range, 0-44), and 455 lesions were concordant. The Curie score for F-MFBG was higher, with an average of 11 (range, 0-25) compared with 8 for I-MIBG (range, 0-22). Of the 273 F-MFBG-positive/I-MIBG-negative lesions, follow-up clinical and imaging assessment was available for 234 lesions in 30 patients, and 100% of these were confirmed true-positive. F-MFBG PET offers faster imaging and superior detection compared with I-MIBG imaging. F-MFBG had high concordance with I-MIBG at the patient level and showed more lesions in most patients. F-MFBG is an attractive alternative to I-MIBG.