Lymphoma: imaging in the evaluation of residual masses

In the management of patients with lymphoma, imaging is essential not only for diagnosis but also to define prognosis and treatment by staging. Imaging is also used to assess the response to treatment that may affect the treatment strategy: new chemotherapeutic drug combinations and autologous stem cell transplantation. These different therapies have increased the need for higher accuracy to assess the response to treatment. Standardised imaging response criteria must be well known by radiologists involved in the management of patients with lymphoma. Criteria are mainly volumetric, and are obtained from CT scans. Functional imaging techniques have been shown to provide better information on the viability of residual masses than does CT assessment of size changes. CT remains the main imaging technique to assess response to treatment based on volumetric international criteria. New functional imaging tools evaluating perfusion (CT and MRI), and particularly glucose uptake (PET), will probably play an important role in bringing additional information on the metabolism of lymphomatous masses.