Intensity of bone involvement: a quantitative 18F-FDG PET/CT evaluation for monitoring outcome of multiple myeloma

• Published in: Nuclear medicine communications Vol. 42; no. 12; p. 1375
• Main Authors: Takahashi, Maria Emilia Seren, Mosci, Camila, Duarte, Gislaine O, Pericole, Fernando V, Metze, Konradin, Lorand-Metze, Irene G H, Ramos, Celso D
• Format: Journal Article
• Language: English
• Published: England 01.12.2021
• Subjects: Adult; Aged; Aged, 80 and over; Bone and Bones - diagnostic imaging; Female; Fluorodeoxyglucose F18; Humans; Male; Middle Aged; Multiple Myeloma - diagnostic imaging; Multiple Myeloma - pathology; Positron Emission Tomography Computed Tomography; Retrospective Studies; Treatment Outcome
• ISSN: 1473-5628
• DOI: 10.1097/MNM.0000000000001470

The parameter intensity of bone involvement (IBI) was recently proposed to quantitatively assess patients with multiple myeloma using 18F-fluorodeoxyglucose-PET combined with computed tomography (18F-FDG PET/CT) images. Here, we aimed to calculate IBI variation (ΔIBI) between two consecutive PET/CT of the same patient and verified its relationship with a subjective visual analysis of the images and with clinical outcome. Consecutive whole-body 18F-FDG PET/CT performed to assess the outcomes of 29 patients diagnosed with multiple myeloma were retrospectively evaluated. ΔIBI was calculated after bone segmentation, using liver standardized uptake value as a threshold to determine metabolically active volumes in the skeleton. For each pair of consecutive PET/CTs, two nuclear medicine physicians classified visually the most recent image as PET-remission, PET-progression or PET-stable when compared to the previous examination. The lowest ΔIBI was -1.27 and the highest was 0.29. PET-remission was related to ΔIBI <0 (median = -0.10; -1.27 to +0.03), while PET-progression was related to ΔIBI >0 (median = 0.02; -0.07 to +0.29). ΔIBI around zero was found in images classified as PET-stable (median = 0.00; -0.08 to +0.06). Significant difference in ΔIBI was found between the three groups. Multivariate stepwise analysis showed that IBI value at diagnostic PET/CT, serum calcium and percentage of plasma cells in the bone marrow are independent prognostic factors. Delta IBI provides quantitative data for variations of 18F-FDG uptake in the bone marrow during the follow-up of the patients. In addition, higher IBI values at diagnosis are associated with a higher risk of patient's death.