The aim of the study is to compare the diagnostic performance of whole-body MRI scan, positron emission tomography + CT, and circulating tumor DNA in patients with hematologic malignancy called diffuse large cell B lymphoma (DLBCL) in staging and restaging, and prognosis.

Patients newly diagnosed with DLBCL or patients with relapsed DLBCL who consent to participate in this study will apart from standard staging and restaging examination with PET/CT undergo whole-body MRI (wbMRI). From blood samples, the level of circulating tumor DNA (ctDNA) fragments will be estimated. These procedures will be repeated during restaging after primary treatment. The diagnostic accuracy of wbMRI in initial staging and restaging will be compared with PET/CT as the gold standard. Circulating tumor DNA levels will be compared at baseline with staging from PET/CT. The change in levels of ctDNA will be compared with the treatement response assessed by PET/CT. All three methods will be used as prognostic indicators.

Inclusion Criteria:

• age ≥18 years
• performance status according to the Eastern Cooperative Oncology Group between 0 and 3
• satisfactory clinical condition to participate in this study
• adequate hematologic and renal functions
• no contraindications to MRI
• recent or planned PET/CT at the institution
• informed consent to participate.

Exclusion Criteria:

• history of indolent lymphoma
• anti-lymphoma treatment initiated before PET/CT or wbMRI
• central nervous system lymphoma

Patients referred to a Department of Hematology at a tertiary university hospital.

The data will be available upon reasonable request to the corresponding author.