Accuracy of whole-body MRI in the assessment of splenic involvement in lymphoma

Abstract

Background Accurate evaluation of the spleen is an important component of staging lymphoma, because this may have prognostic and therapeutic implications. Purpose To determine the diagnostic value of whole-body magnetic resonance imaging (MRI), including diffusion-weighted imaging (whole-body MRI-DWI) in the detection of splenic involvement in lymphoma. Material and Methods This IRB approved, prospective multicenter study included a total of 107 patients with newly diagnosed, histologically proven lymphoma who underwent 1.5 T whole-body MRI-DWI and FDG-PET/CT. Whole-body MRI-DWI and FDG-PET/CT were independently evaluated by a radiologist and a nuclear medicine physician, in a blinded manner. Splenic involvement at MRI was defined as splenic index > 725 cm3 or discrete nodules. At FDG-PET/CT splenic involvement was defined as splenic uptake greater than liver uptake or hypodense nodules at contrast-enhanced CT. FDG-PET/CT augmented with follow-up imaging after treatment was used as reference standard. Results Splenic involvement was detected with FDG-PET/CT in 21 patients, all demonstrating response to treatment. The sensitivity, specificity, positive predictive value, and negative predictive value of whole-body MRI-DWI for the detection of splenic involvement were 85.7 %, 96.5 %, 85.7%, and 96.5%, respectively. Three out of six discrepancies were related to suboptimal criterion of splenic size used with whole-body MRI-DWI versus the size-independent FDG uptake. Conclusion Whole-body MRI-DWI is reasonably accurate in the detection of splenic lymphomatous involvement.