Quantitative bone marrow magnetic resonance imaging in children with lymphoblastic leukaemia

The aim of the study was to evaluate fat fraction (FF) changes in patients diagnosed with acute lymphoblastic leukaemia (ALL) in comparison with children without haematological disorders. All the patients or their legal representatives gave their informed consent to magnetic resonance imaging (MRI). The study was approved by the Independent Ethics Committee and the Scientific Council of the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology and was conducted in line with the Ethical Principles of the World Health Organization (the Declaration of Helsinki) for Medical Research Involving Human Subjects. The study included 33 healthy volunteers aged 13.4 ± 2.8 years (the control group) and 34 patients with acute phase ALL whose mean age was 12.2 ± 3.6 years (the group of interest). Imaging of the pelvic bones and lumbar vertebrae was performed on a Philips Achieva 3T scanner using the mDixon-quant sequence, with a subsequent construction of FF maps. The Mann–Whitney U-test was used to compare the FF data of the cases with each other and with the controls. Four regions of interest were selected, 100 mm2 each: in the bodies of the right and the left iliac bones as well as in the bodies of the L4 and L5 vertebras. For each group of subjects and each region of interest, mean FF was calculated. In the group of the patients with acute phase ALL, FF was the lowest: 3.53 ± 2.75% and 3,72 ± 3.09% in the bodies of the left and right iliac bones respectively, and 2.62 ± 1.86% and 2.47 ± 2.17% in the L4 and L5 vertebras respectively. In the control group, FF in the respective regions of interest was 51.3 ± 9.5%; 49.9 ± 11.0%; 31.3 ± 8.73% and 32.4 ± 10.3%. It is obvious that bone marrow FF in the patients with ALL differs significantly from the control group. Quantitative MRI can become a new method for the assessment of changes in the bone marrow of children with leukaemias.