ABSTRACT
BACKGROUND. Traditional approaches for evaluating multiple myeloma (MM) treatment response have low sensitivity for residual disease. Recent studies highlight the utility of whole-body MRI or FDG PET/CT in evaluating treatment response, with increasing emphasis on DWI. OBJECTIVE. This systematic review was conducted to assess the diagnostic accuracy of whole-body MRI and FDG PET/CT for MM treatment response assessment. EVIDENCE ACQUISITION. Studies in which whole-body MRI or FDG PET/CT was used to evaluate MM treatment response were identified through search of the PubMed and EMBASE databases through June 30, 2021. Pooled sensitivity and specificity for detecting response were calculated by bivariate modeling. The diagnostic performances of whole-body MRI and FDG PET/CT were compared. Subgroup analyses were conducted to assess studies comparing the modalities and studies in which whole-body MRI included DWI. EVIDENCE SYNTHESIS. Twelve studies comprising 373 patients were included: six evaluated both modalities, four evaluated whole-body MRI only, and two evaluated FDG PET/CT only. Of studies of MRI, five included DWI. Pooled sensitivity and specificity were 87% (95% CI, 75-93%) and 57% (95% CI, 37-76%) for whole-body MRI versus 64% (95% CI, 45-79%) and 82% (95% CI, 75-88%) for FDG PET/CT (sensitivity, p = .29; specificity, p = .01). For studies directly comparing the modalities, pooled sensitivity and specificity were 90% (95% CI, 80-100%) and 56% (95% CI, 44-68%) for whole-body MRI versus 66% (95% CI, 47-85%) and 81% (95% CI, 72-90%) for FDG PET/CT (sensitivity, p = .18; specificity, p < .001). Sensitivity and specificity were 93% (95% CI, 75-98%) and 57% (95% CI, 21-87%) for DWI versus 74% (95% CI, 60-85%) and 56% (95% CI, 38-73%) for whole-body MRI without DWI (sensitivity, p = .27; specificity, p = .99). The AUC values were 0.84 for whole-body MRI, 0.83 for FDG PET/CT, and 0.92 for DWI. CONCLUSION. FDG PET/CT had significantly higher specificity, and whole-body MRI had higher sensitivity (though nonsignificant). DWI may contribute to the high sensitivity of whole-body MRI. CLINICAL IMPACT. The results of this meta-analysis suggest potential complementary roles of whole-body MRI and FDG PET/CT in assessment of MM treatment response. Future studies should explore their combination through PET/MRI.