Whole-body imaging, in particular molecular imaging with
fluorine 18 ((18)F)-fluorodeoxyglucose (FDG) positron emission tomography (PET), is essential to management of
lymphoma. The assessment of disease extent provided by use of whole-body imaging is mandatory for planning appropriate treatment and determining patient prognosis. Assessment of treatment response allows clinicians to tailor the treatment strategy during
therapy if necessary and to document complete remission at the end of treatment. Because of rapid technical developments, such as echo-planar sequences, parallel imaging, multichannel phased-array surface coils, respiratory gating, and moving
examination tables, whole-body diffusion-weighted (DW) magnetic resonance (MR) imaging that reflects cell density is now feasible in routine clinical practice. Whole-body DW MR imaging allows anatomic assessment as well as functional and quantitative evaluation of
tumor sites by calculation of the apparent diffusion coefficient (ADC). Because of their high cellularity and high nucleus-to-cytoplasm ratio, lymphomatous lesions have low ADC values and appear hypointense on ADC maps. As a result, whole-body DW MR imaging with ADC mapping has become a promising tool for
lymphoma staging and treatment response assessment. The authors review their 4 years of experience with 1.5-T and 3-T whole-body DW MR imaging used with (18)F-FDG PET/computed tomography at baseline, interim, and end of treatment in patients with
Hodgkin lymphoma and
diffuse large B-cell lymphoma and discuss the spectrum of imaging findings and potential pitfalls, limitations, and challenges associated with whole-body DW MR imaging in these patients.