Mouse models of cancer are extensively used to better understand the pathobiology of the disease, to test potential novel therapies, and for the development of diagnostic and prognostic imaging tools. Currently, diagnosis of acute myeloid leukemia (AML) is quite invasive. It is based predominantly on blast quantification in the blood and bone marrow (BM) analysis, and imaging is not part of the clinical follow-up of the patients. T1 relaxivity of the mouse BM has not been reported previously. . BM of mice injected with AML cells from patients present higher T1 relaxation values than normal BM, and it further increased after chemotherapy treatment. Although analysis of bigger cohorts of patients would be required, our data suggest a good potential for BM T1 monitoring as a non-invasive marker for AML resistance to therapy.