This retrospective study is focused on the possible clinical implications of texture analysis-derived PET parameters in patients with smoldering multiple myeloma. Several texture features are significantly associated with progression to symptomatic multiple myeloma and with a shorter time to progression. The results of this study may lead to early identification of patients who could benefit from specific therapies.
BACKGROUND: The aim of the study was to determine whether positron emission tomography parameters derived from texture analysis of axial and peripheral skeleton predict progression to symptomatic multiple myeloma (MM) in patients undergoing 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) without evidence of focal sites of 18F-FDG uptake.
PATIENTS AND METHODS: Patients with smoldering MM who underwent 18F-FDG PET/CT from May 2014 to June 2018 were retrospectively reviewed. Volumes of interest (VOIs) were placed on T5-T7 and L2-L4, iliac crests, and femoral diaphyses. Dedicated software (LIFEx) allowed us to obtain PET-derived first-, second-, and higher order texture features. Possible associations between PET parameters and progression to symptomatic MM were determined. Kaplan-Meier curves allowed to assess time to progression (TTP) based on the PET parameters.
RESULTS: Forty-five patients were included: 26 patients (58%) did not meet the criteria for symptomatic MM, but 19 patients (42%) progressed to symptomatic MM. Several texture features extracted from VOIs placed on iliac crests and femoral diaphyses were significantly associated with progression to symptomatic MM and with a shorter TTP (P < .05); conversely, the above-mentioned parameters extracted from VOIs placed on T5-T7 and L2-L4 did not significantly differ among the patients with regard to their progression to symptomatic MM and length of TTP, except for the gray-level zone length matrix-short-zone low-gray-level emphasis and gray-level zone length matrix-low gray-level zone emphasis. Particularly, second- and higher order texture features showed a significant association with the above-mentioned outcomes.
CONCLUSION: Texture features derived from PET may be an expression of subtle disease distribution in the axial and peripheral bone marrow.