PET/CT predicts bone marrow involvement in paediatric non-Hodgkin lymphoma and may preclude the need for bone marrow biopsy in selected patients

To investigate the role of F-18-FDG PET/CT to detect bone marrow (BM) involvement in paediatric non-Hodgkin lymphoma (NHL). Pretreatment PET/CT scans from 93 consecutive paediatric patients with NHL were retrospectively reviewed. Patterns of BM FDG uptake and standardized uptake value of the fifth lumbar vertebra (SUVBM) were compared with bone marrow biopsy (BMB) for diagnosis of BM involvement. Of 93 patients, 41 were judged to have BM involvement. Thirty-nine were identified by PET/CT, versus 23 by BMB. Sensitivity and specificity were 95 % and 98 % for PET/CT and 56 % and 100 % for BMB, respectively. None of the patients with BM FDG uptake lower than liver had positive BMB. In 45 patients presenting homogeneously increased BM uptake, positive BMB was achieved in 93 % (14/15) of patients with FDG uptake expanding to the distal portion of extremities, compared to 7 % (2/30) of those without. A multifocal pattern was observed in 25 patients and 18 had negative BMB. SUVBM differentiated BM involvement from benign BM activation with an area under the curve of 0.885 (p < 0.001). PET/CT had a high level of accuracy for detecting BM involvement in paediatric NHL. BMB might be omitted in selected patients. Non-PET/CT allows for accurate detection of bone marrow involvement. Patterns of bone marrow FDG uptake are highly correlated with marrow disease. Bone marrow biopsy could be omitted in selected paediatric patients.