Objectives: To compare the diagnostic efficiency of whole-body MRI-DWI and PET/CT in lymphoma staging.
Methods: A prospective study enrolled 92 patients with lymphoma. Prior to treatment, all patients underwent whole-body MRI-DWI and PET-CT. The methods' efficiency was compared in the diagnosis of lymph node (LN) and organ involvement, and in determining lymphoma stage.
Results: Sensitivity, specificity, and accuracy in the diagnosis of enlarged LN involvement were 98.2%, 99.9%, and 99.3%, respectively, for MRI-DWI, and 99.4%, 100.0%, and 99.8%, respectively, for PET/CT. ROC analysis showed similar methods' efficiency in the diagnosis of enlarged LN involvement (p > 0.06). MRI-DWI and PET/CT sensitivity in the diagnosis of non-enlarged LN involvement was 77.8% and 88.1%, respectively (p < 0.001). MRI-DWI and PET/CT sensitivity, specificity, and accuracy in the diagnosis of lung involvement were 73.3%, 98.7%, 94.6% and 86.7%, 98.7%, 96.7%; spleen involvement 54.8%, 98.3%, 83.3% and 100.0%, 100.0%, 100.0%; bone marrow involvement 87.1%, 96.4%, 93.0% and 64.5%, 87.3%, 79.1%; and all-organ involvement 72.9%, 98.1%, 91.4% and 80.0%, 96.6%, 92.2%, respectively. ROC analysis showed similar methods' efficiency in the diagnosis of lung involvement (р > 0.3), higher for PET/CT in spleen involvement (р < 0.0001), higher for MRI-DWI in bone marrow involvement (р < 0.0008), and similar in all-organ involvement (р > 0.35). MRI-DWI and PET/CT determined the correct lymphoma stage in 79 (86%) patients.
Conclusions: Whole-body MRI-DWI and PET/CT determined the correct lymphoma stage in similar numbers of patients. MRI-DWI can serve as a non-irradiative alternative to PET/CT in lymphoma staging.
Key points: • Whole-body MRI-DWI efficiency compared with that of PET/CT is similar in the diagnosis of enlarged LN involvement, inferior in the diagnosis of non-enlarged LN and spleen involvement, but superior in the diagnosis of bone marrow involvement. • A new efficient MRI-DWI sign for diagnosis of diffuse bone marrow involvement has been proposed, i.e., a diffuse increase in spine signal intensity on high b value DWI images above the kidney parenchyma. • MRI-DWI and PET/CT determined the correct lymphoma stage in similar numbers of patients.
Keywords: Diffusion magnetic resonance imaging; Hodgkin lymphoma; Neoplasm staging; Non-Hodgkin lymphoma; Positron emission tomography computed tomography.