REFINING INTERPRETATION OF METAIODOBENZYLGUANIDINE SCANS IN CHILDREN

In pediatrics, the distribution of radioiodinated metaiodobenzylguanid ine (MIBG) has been studied primarily in neuroblastoma. However, norma l patterns in children show a number of particularities and pitfalls r elated to the context of pediatric oncology which must be identified. Methods: We report on 28 equivocal scans in 24 children. In all cases, two experienced observers judged the scans to be equivocal and the de finite interpretations were confirmed by follow-up. Results: Difficult ies in interpreting the scans were observed at the level of the thorax (15 patients), the abdomen (5 patients), the head (4 patients) or els ewhere (4 patients). The final interpretation of the scans was attribu ted to an unusual physiological pattern linked to age (9 patients), tu moral context (17 patients) or artifacts (2 patients). Conclusions: A number of important physiological areas of uptake in soft tissues can lead to false-positive interpretations of normal scans, such as the ph ysiological upper thoracic uptake which has never been previously desc ribed. Numerous technical and physiological possibilities exist and th ose pitfalls must be ruled out. A precise knowledge of these technical difficulties and physiological variants can reduce the number of equi vocal MIBG scans.