Refining interpretation of MIBG scans in children.

Abstract

In pediatrics, the distribution of radioiodinated metaiodobenzylguanidine (MIBG) has been studied primarily in neuroblastoma. However, normal patterns in children show a number of particularities and pitfalls related to the context of pediatric oncology which must be identified. We report on 28 equivocal scans in 24 children. In all cases, two experienced observers judged the scans to be equivocal and the definite interpretations were confirmed by follow-up. Difficulties in interpreting the scans were observed at the level of the thorax (15 patients), the abdomen (5 patients), the head (4 patients) or elsewhere (4 patients). The final interpretation of the scans was attributed to an unusual physiological pattern linked to age (9 patients), tumoral context (17 patients) or artifacts (2 patients). A number of important physiological areas of uptake in soft tissues can lead to false-positive interpretations of normal scans, such as the physiological upper thoracic uptake which has never been previously described. Numerous technical and physiological possibilities exist and those pitfalls must be ruled out. A precise knowledge of these technical difficulties and physiological variants can reduce the number of equivocal MIBG scans.