Imaging, QoL and Patient-Reported Outcome and Supportive Care

Category: Imaging, QoL and Patient-Reported Outcome and Supportive Care

Imaging quality and detection ability of whole-body low-dose CT for bone and extraosseous lesions in multiple myeloma

(PA-140) Imaging Quality and Detection Ability of Whole-body Low-dose CT for Bone and Extraosseous Lesions in Multiple Myeloma

Thursday, September 18, 2025

Hirokazu Miki, MD, PhD

Hospital Professor
Division of Transfusion Medicine and Cell Therapy, Tokushima University Hospital

Introduction: Since bone disease is the most frequent disease-related condition of multiple myeloma (MM), cross-sectional imaging modalities play an important role in detection of bone disease in MM. While whole-body low-dose CT (WBLDCT) is recommended to assess bone disease by the latest diagnostic criteria of IMWG, there is little information on imaging quality assessment and protocol of WBLDCT for MM bone disease. We herein aimed to evaluate the imaging quality and detection ability of WBLDCT compared with whole-body standard-dose CT (WBSDCT) in MM patients for bone and extraosseous lesions.

Methods:   We retrospectively analyzed MM patients with bone disease who underwent WBCT from January 2020 to May 2025 in Tokushima University. All MM patients underwent both WBLDCT and WBSDCT within one year after diagnosis with 320-rows scanner CT machine (Canon Medical Systems, Otawara, Japan). We calculated the contrast-to-noise ratios (CNRs) of the gluteus medius muscle and lumbar spine (L4) to air in WBLDCT and WBSDCT. Statistical analyses were performed using the Mann- Whitney U test to compare the mean of data between the groups, and Spearman’s rank correlation test to assess relationships between quantitative values.

Results:   Thirty MM patients with a median age of 70.5 (range 53-85) were evaluated. R2-ISS was diagnosed with Low, Low-Intermediate, Intermediate-High, and High in 5, 10, 10, and 5 patients, respectively. Radiation exposure dose was significantly lower in WBLDCT than WBSDCT (3.54 ± 1.94 vs 11.54 ± 5.25 mGy, respectively; p< 0.0001). Body mass index (BMI) was 24.26 ± 3.91 kg/m²; radiation exposure dose was proportionally increased with BMI in both WBLDCT and WBSDCT. CT values were 47.66 ± 9.20 vs 45.64 ± 10.88 HU in muscle (p=0.610) and 87.96 ± 30.51 vs 92.00 ± 35.67 HU in bone (p=0.728) by WBLDCT and WBSDCT, respectively. CNRs of muscle and bone were comparable between WBLDCT and WBSDCT (89.89 ± 24.14 vs 103.22 ± 34.38 in muscle [p=0.072]; 42.77 ± 18.82 vs 43.88 ± 18.04 in bone [p=0.773], respectively). However, CNRs of muscle in obese MM patients (BMI > 25, n=11) were significantly lower in WBLDCT than WBSDCT (90.25 ± 18.33 vs 116.95 ± 38.72 in muscle [p=0.003]).

Conclusions:

Besides generally accepted advantages of lower radiation exposure and ease of use, these results suggest that WBLDCT may provide therapeutically important information on not only bone disease but also lesions outside of bone, including extramedullary disease and other comorbidities in non-obese MM patients. A multi-center prospective study can be warranted to further optimize CNRs in WBLDCT as a whole-body screening modality by low-dose techniques, including tuning radiation doses, especially in MM patients with obesity.