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A B S T R A C T PurposeChildren with relapsed neuroblastoma have poor survival. It is crucial to have a reliable method for evaluating functional response to new therapies. In this study, we compared two functional imaging modalities for neuroblastoma: metaiodobenzylguanidine (MIBG) scan for uptake by the norepinephrine transporter and [18 F]fluorodeoxyglucose positron emission tomography (FDG-PET) uptake for glucose metabolic activity. Patients and MethodsPatients enrolled onto a phase I study of sequential infusion of iodine-131 ( 131 I) MIBG (NANT-2000-01) were eligible for inclusion if they had concomitant FDG-PET and MIBG scans.131 I-MIBG therapy was administered on days 0 and 14. For each patient, we compared all lesions identified on concomitant FDG-PET and MIBG scans and gave scans a semiquantitative score. ResultsThe overall concordance of positive lesions on concomitant MIBG and FDG-PET scans was 39.6% when examining the 139 unique anatomic lesions. MIBG imaging was significantly more sensitive than FDG-PET overall and for the detection of bone lesions (P Ͻ .001). There was a trend for increased sensitivity of FDG-PET for detection of soft tissue lesions. Both modalities showed similar improvement in number of lesions identified from day 0 to day 56 scan and in semiquantitative scores that correlated with overall response. FDG-PET scans became completely negative more often than MIBG scans after treatment. ConclusionMIBG scan is significantly more sensitive for individual lesion detection in relapsed neuroblastoma than FDG-PET, though FDG-PET can sometimes play a complementary role, particularly in soft tissue lesions. Complete response by FDG-PET metabolic evaluation did not always correlate with complete response by MIBG uptake.

Renal artery lesions associated with neurofibromatosis may involve stenosis and aneurysm formation at all levels of the renal artery to the intraparenchymal branches, and usually are associated with hypertension. A 13-year-old boy with type I neurofibromatosis and severe hypertension presented with multiple aneurysms and multiple stenotic lesions in the renal artery and segmental arteries. The patient underwent ex-vivo renal artery repair with autologous hypogastric artery and autotransplantation to the iliac fossa and was clinically improved. The characteristic histologic findings are presented. A review of the recent literature comparing different treatment modalities for renovascular hypertension in children with neurofibromatosis suggests that surgery remains the best treatment alternative.