Whole body MRI with qualitative and quantitative analysis of DWI for assessment of bone marrow involvement in lymphoma

Aim: Our study aimed to investigate the role of qualitative and quantitative whole body MRI with DWI for assessment of bone marrow involvement (BMI) in newly diagnosed lymphoma using FDG PET\u2013CT and bone marrow biopsy (BMB) as reference standard. Materials and methods: We retrospectively evaluated 56 patients with newly diagnosed lymphoma (21 Hodgkin\u2019s lymphoma and 35 non-Hodgkin\u2019s lymphoma) who underwent random unilateral BMB, FDG PET\u2013CT and Wb-MRI-DWI for initial staging. In a patient-based analysis, results of Wb-MRI-DWI were compared with FDG PET\u2013CT and BMB. For quantitative analysis, mean ADC values of posterior iliac crest were correlated with BMI and bone marrow cellularity. Results: WB-MR-DWI obtained excellent concordance with FDG PET\u2013CT both in HL (k = 1.000; 95% CI 1.000\u20131.000) and in DLBCL (k = 1.000; 95% CI 1.000\u20131.000). In other NHL, WB-MRI-DWI obtained a good correlation with BMB (k = 0.611; 95% CI 0.295\u20130.927) while FDG PET\u2013CT had poor concordance (k = 0.067; 95% CI 0.372\u20130.505). WB-MR-DWI has no false negative errors but 4 false positive results consisting in focal lesions consensually reported by FDG PET\u2013CT and resolved after therapy. No significant correlation between ADC mean value and BMI was found (p = 0.0586). Conclusion: Our data suggest that Wb-MRI-DWI is a valid technique for BMI assessment in lymphoma patients, thanks to its excellent concordance with FDG PET\u2013CT and good concordance with BMB (superior than FDG PET\u2013CT). If further investigations will confirm our results on larger patient groups, it could become a useful tool in the clinical workup