Abstract

OBJECTIVE: To compare the diagnostic accuracy of diffusion-weighted (DW)-MRI with b-values of 50s/mm2 and 800s/mm2 for the detection of bone marrow metastases in children and young adults with solid malignancies.METHODS: In an institutional review board-approved prospective study, we performed 51 whole-body DW-MRI scans in 19 children and young adults (14 males, 5 females; age range: 1-25years) with metastasized cancers before (n=19 scans) and after (n=32 scans) chemotherapy. Two readers determined the presence of focal bone marrow lesions in 10 anatomical areas. A third reader measured ADC and SNR of focal lesions and normal marrow. Simultaneously acquired 18F-FDG-PET scans served as the standard of reference. Data of b=50s/mm2 and 800s/mm2 images were compared with the Wilcoxon signed-rank test. Inter-reader agreement was evaluated with weighted kappa statistics.RESULTS: The SNR of bone marrow metastases was significantly higher compared to normal bone marrow on b=50s/mm2 (mean±SD: 978.436±1239.436 vs. 108.881±109.813, p<0.001) and b=800s/mm2 DW-MRI (499.638±612.721 vs. 86.280±89.120; p<0.001). On 30 out of 32 post-treatment DW-MRI scans, reconverted marrow demonstrated low signal with low ADC values (0.385*10-3±0.168*10-3mm2/s). The same number of metastases (556/588; 94.6%; p>0.99) was detected on b=50s/mm2 and 800s/mm2 images. However, both normal marrow and metastases exhibited low signals on ADC maps, limiting the ability to delineate metastases. The inter-reader agreement was substantial, with a weighted kappa of 0.783 and 0.778, respectively.CONCLUSION: Bone marrow metastases in children and young adults can be equally well detected on b=50s/mm2 and 800s/mm2 images, but ADC values can be misleading.

View details for DOI 10.1007/s00256-022-04240-0

View details for PubMedID 36441237