18F-FDG PET Scan and MRI Diffusion.Evaluation of the Early Therapeutic Response of Diffuse Large B-cell Lymphoma

Inclusion Criteria:

* Patient with Diffuse Large B-Cell Lymphoma confirmed histologically
* Patient with a tumor mass defined as measurable according to the RECIST 1.1 criteria,
* Patient requiring a standard first-line chemotherapy treatment (Rituximab -Cyclophosphamide - Hydroxyadriamycin - Oncovin - Prednisone = R-CHOP every 21 days),
* Patient older than 18 years,
* Performance status less than or equal to 2,
* Biological assessment meeting the following criteria: creatinine \<150 μmol / l or creatinine clearance\> 40 ml / min, total bilirubin \<30 μmol / l, transaminases \<2.5 x ULN
* Patient of childbearing age must agree to use Means of effective contraception during the treatment period,
* Patient having read the information note and having signed informed consent,
* Patient with Health care insurance available.

Exclusion Criteria:

* History of malignant hemopathy or solid tumor
* History of previous chemotherapy
* Contraindication to one of the examinations studied (Claustrophobia, Pacemaker ...)
* Patient included in another clinical trial for which a period of exclusion is mentioned.
* Patient considered to be a vulnerable person; Vulnerable persons are defined in article L1121-5 to - 8: Pregnant women, women who are pregnant, women who are breastfeeding, Persons deprived of their liberty by a judicial or administrative decision, persons who are hospitalized without consent under Articles L. 3212-1 and L. 3213-1 which do not fall under the provisions of Article L. 1121-8 and persons admitted to a health or social institution for purposes other than research Persons who are the subject of a legal protection measure or are unable to give their consent.