Measuring bone marrow fat fraction using the Dixon technique (FFDix) might be an excellent noninvasive biomarker of sickle cell disease (SCD) severity and hemolysis intensity, according to a recent article published in the journal Clinical Radiology.

For the purpose of this cross-sectional study, conducted between December 2018 and September 2019, the researchers recruited 48 patients (26 homozygous and 22 compound heterozygous individuals) and 48 healthy volunteers at the Clínica Delfin Medicina Diagnostica in Brazil.

The participants were required to complete a questionnaire regarding their sociodemographic data, previous clinical events, and hydroxyurea use. The researchers performed a thorough evaluation of the patients’ medical records before they underwent routine laboratory examinations. Next, all participants were subjected to an MRI of the lumbar spine and pelvis by Dixon technique.

In addition, SCD severity was assessed through available clinical and laboratory data, and an online “Sickle Cell Disease Severity Calculator.” Laboratory cut-off values indicated a high degree of hemolysis in 19 patients. The study authors also performed analyses such as Pearson’s correlation, receiver operating characteristic (ROC) curve, and binary logistic regression analysis.

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According to the results, lower FFDix values were found in patients with SCD compared with the control group, and the reduction was especially pronounced in the HbSS subtype and patients with a higher degree of hemolysis. Patients with a higher degree of hemolysis using hydroxyurea (medium dosage 9.8 mg/kg/day) also had lower FFDix.

In addition, ROC curves and odds ratios for detecting patients with a higher degree of hemolysis at the different FFDix measurement sites (such as the iliac bones, femoral head, and lumbar vertebrae) demonstrated excellent performance.

“Grading the severity of SCD is challenging due to the difficulty in bringing together clinical and environmental data in a single biomarker,” Freitas Lins and colleagues wrote.

Despite numerous efforts to develop a comprehensive severity classification for SCD, the evidence supporting the use of a specific biomarker remains scarce.

Reference

Freitas Lins C, Garrido Salmon CE, Amorim de Souza L, Saldanha Quesado RC, de Souza Moraes R, Silva-Pinto AC, Almeida Matos M, Nogueira-Barbosa MH. Quantitative MRI evaluation of bone marrow in sickle cell disease: relationship with haemolysis and clinical severity. Clin Radiol. Published online December 26, 2022. doi:10.1016/j.crad.2022.11.014