Whole body diffusion-weighted imaging is a functional magnetic resonance imaging technique that characterizes tissue by probing changes in water diffusion secondary to differences in the tissue microstructure. These changes in water diffusion result in differences in signal intensity on diffusion-weighted-images that are quantified with the apparent diffusion coefficient (ADC). In malignant lesions, the extravascular extracellular space (EES) will be diminished, due to the increased number of cells. This will restrict water diffusion, identified by increased signal intensity (SI) on native DWI images and low ADC. Several studies indicate the value of DWI for differentiation of benign and malignant lymph nodes, detection of tumor recurrence and for ADC-based prediction of treatment outcome in various solid tumours (Koh DM et al, Am J Roentgenol 2007).

Patients with a new diagnosis of Hodgkin or Non-Hodgkin Lymphoma (only diffuse large B-cell lymphoma, follicular lymphoma, mantle cell lymphoma and PTLD) will be included in the study. These patients will receive a WB-DWI scan before treatment, once or twice during treatment (depending on the type of lymphoma) and after the completion of the treatment. The MRI scan will be performed on a 3 Tesla-MRI system without contrast administration and without exposing the patient to radiation.

Whole body diffusion-weighted images will be prospectively interpreted by two experienced radiologists, blinded to all clinical and imaging data. Findings will be correlated to FDG-18F-2-fluoro-2-deoxy-D-glucose fluorodeoxyglucose , biopsies performed in clinical routine (bone marrow always - soft tissue lesions if indicated) and imaging follow-up.

The purpose of this study is:

• to evaluate Whole body diffusion-weighted imaging for staging of lymphoma
• to evaluate Whole body diffusion-weighted imaging as an early predictive biomarker for treatment outcome
• to evaluate Whole body diffusion-weighted imaging for differentiating residual tumor from post therapy changes

Inclusion Criteria:

• every patient with a new diagnosis of Hodgkin or Non-Hodgkin Lymphoma (only diffuse large B-cel lymphoma, mantle cell lymphoma, follicular lymphoma and PTLD)

Exclusion Criteria:

• patient with general contraindications for MRI (pacemaker, claustrophobia, etc.)
• patients with a type of lymphoma other than those described in the inclusion criteria