PET/CT in paediatrics: it is time to increase its use!

Abstract

F-FDG PET and PET/CT have proved to beuseful tools in oncological patients [1]. For example, it hasbeen reported that PET can modify the initial staging inabout 40% of patients with lymphoma, leading tomodification of therapy in 18% of them [2]. Similarresults in terms of clinical management, i.e. changes instaging and treatment, have been described in large seriesof patients with other malignancies. PET and PET/CThave also been shown to exert a high impact ononcological management in the paediatric population [3–5]. However, the low incidence of the paediatric malig-nancies has made it difficult to elucidate the precise role ofthese examinations and to attain evidence-based indica-tions for them. Nevertheless, more and more papers havebeen published demonstrating that FDG PET/CT is alsouseful in children. Results obtained in paediatric lympho-ma patients have shown high rates (up to 23%) of therapychanges owing to FDG PET results [6], and several recentpapers have described the usefulness of this technique inmost other paediatric malignancies, such as neuroblastomaand sarcomas.What is the situation regarding correlative image? Inboth children and adults it is clear that imaging diagnosis ismore accurate when anatomical and metabolic images areinterpreted together. Hybrid equipment and fusion imaging(and PET/CT is probably the reference) provide betterinformation than is acquired by separate anatomical andmetabolic examinations or even by comparison of them.This fact is encouraging imaging specialists (in CT, MRI,nuclear medicine, etc.) to collaborate more closely, therebyincreasing communication, improving reports and increas-ing the clinical impact of imaging modalities [1, 2].Several papers, even in paediatric oncology, havereported that fused PET/CT improves diagnostic accuracycompared with PET alone or side by side comparison ofPET and CT images [6, 7]. An excellent example of thisbenefit is given in a recently published paper from theGerman Society of Paediatric Oncology and Hematologyon Hodgkin’s disease. This prospective, multicentre studycompares the accuracy of conventional imaging methodsand FDG PET in the initial staging of paediatric patientsdiagnosed with Hodgkin’s lymphoma. Twenty-one nodaland six extranodal regions were evaluated by conventionalimaging methods and FDG PET independently, and laterthe images were also compared side by side and fused.Results were statistically superior when anatomical regionswere evaluated using both methods in combination. Nodifferences were observed according to the way in whichthe methods were combined, i.e. side by side viewing orimage fusion. However, the confidence of analysts in theresults was clearly superior when the fusion method wasused [8].In this issue, Zvi Bar-Sever et al. describe the results of aprospective study on 46 consecutive paediatric patients whounderwent