Comparison of the diagnostic effectiveness of whole body magnetic resonance imaging with diffusion weighted imaging and positron emission tomography/computed tomography in determining tumor response in lymphoma after the end of chemotherapy: Minsk scaleand Deauville scale

Abstract

Introduction . Positron emission tomography/computed tomography (PET/CT) is a recommended technique for tumor response evaluation in lymphoma after treatment. The possibilities of the whole body magnetic resonance imaging with diffusion-weighted imaging (MRI-DWI) for tumor response evaluation in lymphoma are not well studied. Objective: to compare the diagnostic effectiveness of whole body MRI with a diffusion-weighted imaging (MRI-DWI) and PET/CT in determining tumor response in lymphoma after the end of chemotherapy. Materials and methods . A prospective study included 105 adult patients with lymphoma whounderwent whole body MRI-DWI and PET/CTafter the end of chemotherapy and who were followed-up for at least 6 months. To interpret the MRI-DWI, the 5-level scale (Minsk scale) proposed by us was used. Categories 1–3 were considered a sign of complete tumor response, categories 4–5 were a sign of non-complete response. Results . According to the reference standard, complete tumor response was established in 77% of patients, non-complete response in 23%. The assessment of the tumor response in MRI-DWI and PET/CT matched in 89% of patients. The agreement of MRI-DWI (k =0,76, p=0,000) and PET/CT (k =0,78, p=0,000) with the reference standard is good. The sensitivity, specificity, accuracy, positive and negative prognostic value of MRI-DWI were 66,7%, 100,0%, 92,4%, 100,0%, 91,0%, PET/CT — 83,3%, 95,1%, 92,4%, 83,3%, 95,1%, respectively. The diagnostic effectiveness of the methods is not significantly different (p=0,32). The most common reason for the incorrect determination of the tumor response in MRI-DWI was non-enlarged lymph nodes, and in PET/CT — metabolically active non-tumor diseases. 3-year progression-free survival with negative and positive MRI-DWI results was 93% and 25% (p=0,000), 3-year overall survival — 97% and 70% (p=0,011), respectively. Conclusion . Whole body MRI-DWI and Minsk scale are recommended for use in patients with lymphoma to determine tumor response after the end of chemotherapy as a non-irradiative and effective alternative to PET/CT.