Role of whole-body MRI for treatment response assessment in multiple myeloma: comparison between clinical response and imaging response

Abstract

Background: Whole-body MRI (WB-MRI) including diffusion-weighted image (DWI) have been widely used in patients with multiple myeloma. However, evidence for the value of WB-MRI in the evaluation of treatment response remains sparse. Therefore, we evaluated the role of WB-MRI in the response assessment.Methods: In our WB-MRI registry, we searched multiple myeloma patients treated with chemotherapy who underwent both baseline and follow-up WB-MRI scans. Clinical responses were categorized as complete response (CR), partial response (PR), stable disease (SD), or progressive disease (PD), using IMWG criteria. Using RECIST 1.1, MD Anderson (MDA) criteria, and MDA-DWI criteria, imaging responses on WB-MRI were rated as CR, PR, SD, or PD by two radiologists independently. Then, discrepancy cases were resolved by consensus. Weighted Kappa analysis was performed to evaluate agreement between the imaging and clinical responses. The diagnostic accuracy of image responses in the evaluation of clinical CR, objective response (CR and PR), and PD was calculated. Results: Forty-two eligible patients were included. There was moderate agreement between imaging and clinical responses (κ = 0.54 for RECIST 1.1, κ = 0.58 for MDA criteria, κ = 0.69 for MDA-DWI criteria). WB-MRI showed excellent diagnostic accuracy in assessment of clinical PD (sensitivity 88.9%, specificity 94.7%, positive predictive value [PPV] 84.2%, negative predictive value [NPV] 96.4% in all three imaging criteria). By contrast, WB-MRI showed low accuracy in assessment of clinical CR (sensitivity 4.5%, specificity 98.1%, PPV 50.0%, NPV 71.2% in all three imaging criteria). As to the clinical objective response, the diagnostic accuracy was higher in MDA-DWI criteria than RECIST 1.1 and MDA criteria (sensitivity/specificity/PPV/NPV, 84.2%/94.4%/98.0%/65.4, 54.4%/100%/100%/40.9, and 61.4%/94.4%/97.2%/43.6%, respectively). Conclusions:In the imaging response assessment of multiple myeloma, WB-MRI showed excellent performance in the evaluation of PD, but not in the assessment of CR or objective response. When adding DWI to imaging response criteria, diagnostic accuracy for objective response was improved and agreement between imaging and clinical responses was increased.

Repeatability and reproducibility of ADC measurements: a prospective multicenter whole-body-MRI study

“…Whole-body (WB)-MRI with diffusion-weighted imaging (DWI) is a sensitive tool for visual detection of abnormal foci within bones and soft tissue, in cancer and inflammatory diseases [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. The evaluation of apparent diffusion coefficient (ADC) derived from DWI is used for lesion characterization and assessment of the response to treatment [17].…”

Radiotherapy Response Assessment of Multiple Myeloma: A Dual-Energy CT Approach With Virtual Non-Calcium Images

“…Furthermore, we did not include gold standard imaging from a second modality such as MRI or clinical therapy response as validation for our findings. The relationship of radiological response and clinical response in MM is a common limitation for investigation of novel imaging approaches, which has evoked dedicated studies by itself ( 28 , 29 ). Such investigation should also follow for external validation of our findings and correlation with clinical outcomes but was beyond the scope of our feasibility study.…”

Correlations between apparent diffusion coefficient values of WB-DWI and clinical parameters in multiple myeloma

“…In addition, this study has shown that the average ADC of patients in the CR/VGPR group increases significantly after induction chemotherapy [ 41 ]. However, Park et al [ 42 ] considered that MR imaging was useful in the evaluation of PD (sensitivity 94.7%, specificity 84.2%), but the evaluation of CR was not satisfactory (sensitivity 4.5%, specificity 98.1%), which also involved the information of the ADC map. When the baseline ADC value is 0.808 × 10 –3 mm 2 /s, ADC has the specificity of 68.05% and sensitivity of 54.09% in predicting the increase in ADC after treatment [ 43 ].…”