This research study is designed to test whether the results of a diffusion MRI scan performed after one cycle of chemotherapy for lymphoma can accurately predict the outcome of treatment for individual patients.

Different types of functional imaging are under investigation as a tool to predict response to treatment, as imaging soon after starting therapy might be able to better define the likelihood of response. Functional imaging refers to scans that measure characteristics other than size and shape (anatomic imaging), as measured by CT scans. We are interested in evaluating the potential value of diffusion Magnetic Resonance Imaging (dMRI), which in some settings can be used very early in treatment in predicting patients' response to treatment.

Diffusion MRI (dMRI) detects changes in cell structure, and has the potential to detect and measure cell changes that occur in response to treatment. Several groups are investigating the use of dMRI to monitor treatment responses. This strategy has been most frequently explored in humans in patients with brain tumors, where dMRI has been demonstrated to predict response to treatment early after starting treatment. A few studies have looked at response in other cancers. These studies showed early changes in patients who later responded to treatment, with changes seen within one to 2 weeks.

Although diffusion MRI has been shown to be useful in several cancer types, it has not been explored in the evaluation of lymphoma. This pilot study will evaluate the imaging characteristics of DLBCL by dMRI prior to treatment and 7 days after initial chemotherapy in order to explore whether dMRI is useful in evaluating the response of lymphoma to chemotherapy.

Inclusion Criteria:

• Patients with a new diagnosis of CD20+ diffuse large B cell lymphoma (LBCL) of any stage, including subtypes mediastinal large B cell, centroblastic, immunoblastic, T cell rich B cell and anaplastic B cell lymphoma, who will receive standard R/CHOP as first line chemotherapy will be included.
• Patients must be age 18 or older.
• No selection will be made on the basis of gender, race or ethnicity.

Exclusion Criteria:

• Patients will be excluded if the diagnosis of diffuse large B cell lymphoma cannot be confirmed.
• Patients receiving treatment other than R/CHOP or R/CHOP followed by radiotherapy or who have previously been treated for DLBCL will be excluded. - Patients with HIV infection will also be excluded. No selection will be made based on other medical problems or laboratory values, except as they affect the patient's eligibility to receive standard R/CHOP chemotherapy as determined by the treating physician.
• Patients who have magnetic metal implants or fragments in their body that are incompatible with MRI will be excluded.