Bone marrow cellularity assessment using magnetic resonance imaging in children with aplastic anemia

Aplastic anemia is a life-threatening condition characterized by the suppression of all hematopoietic lineages in the bone marrow. Empty intertrabecular spaces are replaced by adipose tissue. With modern MR techniques for assessing fat fraction, it has become possible to capture these changes. The fat fraction is estimated as the ratio of the signal intensity from fat to the sum of the fat and water signals. Aim of the study: to assess the diagnostic value of bone marrow fat fraction quantification in patients aged < 18 years with aplastic anemia. 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 of the Ministry of Healthcare of the Russian Federation. The study included 66 participants aged under 18 years. A control group consisted of 33 healthy subjects with a mean age of 13.03 ± 2.83 years. A group of interest included 33 children with a confirmed diagnosis of aplastic anemia, with a mean age of 12.31 ± 4.39 years. The study was carried out at the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology of the Ministry of Healthcare of the Russian Federation; all scanning was performed on a Philips Achieva 3.0T MRI scanner using the mDixon-quant sequence in the iliac bones and lumbar vertebrae. Our results showed that bone marrow fat fraction was significantly higher in the aplastic anemia group than in the controls. In the patients with aplastic anemia, the mean fat fraction values in the iliac bones and in the L4, L5 vertebrae were 82.62 ± 10.92% and 73.52 ± 17.52%, respectively. In the control group, the mean fat fraction values for these sites were 51.04 ± 11.41% and 31.43 ± 10.61%, respectively. We found a significant difference in fat fraction values for the same sites between the groups (p < 0.01). Bone marrow fat fraction quantification by MRI allows for the detection of decreased cellularity of the marrow in patients under 18 years of age with aplastic anemia compared to healthy children.