MRI Could Aid in Early Differential Diagnosis of DMD, BMD

Multiparametric quantitative MRI (qMRI) effectively differentiated between Becker muscular dystrophy (BMD) and Duchenne muscular dystrophy (DMD) in ambulatory children in a study published in the Journal of Magnetic Resonance Imaging.¹ The findings suggest multiparametric qMRI could help differentiate between DMD and BMD early and potentially improve treatment outcomes for patients with these conditions.

DMD and BMD are the most common dystrophinopathies affecting boys, accounting for 80% of the disease spectrum,² the authors noted. Differentiating DMD and BMD is important because they require distinct therapeutic approaches—corticosteroids can effectively treat DMD but are less beneficial for BMD. Early and accurate diagnoses are crucial, especially for young children showing mild symptoms.¹

Multiparametric quantitative MRI could potentially help differentiate between Duchenne muscular dystrophy and Becker muscular dystrophy early and improve the management of these conditions. | Image credit: megaflopp - stock.adobe.com

“However, for young ambulatory pediatric patients with mild functional impairment, especially before entering the age of 10, identifying the specific type is challenging due to high overlapping clinical symptoms and signs,” the authors wrote. “This early stage is pivotal for prescribing corticosteroids in DMD patients, as it is important for preserving muscle function and enhancing long-­term outcomes.”

qMRI is a key tool for analyzing the structure and composition of skeletal muscle and finding subtle pathological changes, and in muscular dystrophies, such measures are linked with motor function in patients. The study authors noted that qMRI has potential for identifying the subtle differences between patients with DMD and BMD and could facilitate early differential diagnosis when the diseases are still mild and children are ambulatory.

The study involved 159 participants, including 129 children diagnosed with DMD, 30 with BMD, and 27 healthy controls. The MRI scans, conducted using a 3.0T MR scanner, included Dixon sequences, T1 mapping, and T2 mapping. The analysis aimed to characterize muscle composition and detect subtle pathological changes indicative of muscular dystrophies. All patients underwent the NorthStar Ambulatory Assessment (NSAA) to measure motor function.

The authors found that qMRI parameters—fat fraction (FF), longitudinal relaxation time (T1), and transverse relaxation time (T2) in the pelvic girdle and thigh muscles—were effective in distinguishing between DMD and BMD, especially in younger children with mild functional decline.

FF was the preferred biomarker for differentiation, supplemented by T1 and T2 measurements. Compared with healthy controls, patients with DMD showed significantly higher FF in 17 out of 18 muscles; patients with BMD showed significantly higher FF in 8 out of 18 muscles. Patients with DMD also had significantly higher T2 in all 18 muscles vs healthy controls, and those with BMD had higher T2 in 17 of 18 muscles vs healthy controls. T1 was significantly lower in 7 out of 18 muscles in patients with DMD vs healthy controls, but there were no significant differences in the BMD group compared with healthy controls.

There were also significant differences in FF in patients with mild BMD and DMD under 10 years old compared with healthy controls. FF was higher in 5 of 18 muscles in patients with mild BMD vs healthy controls and in 11 of 18 muscles in patients with mild DMD vs healthy controls. In both mild BMD and mild DMD, all 18 muscles showed higher T2 than healthy controls. Six out of 18 muscles in those with mild DMD had significantly higher T1, but no significant differences were seen in mild BMD compared with healthy controls.

“This study evaluated the potential of multiparametric qMRI for differentiating between ambulatory children with BMD and DMD,” the authors wrote. “Our primary findings reveal that qMRI biomarkers demonstrate effective differential diagnostic capabilities, particularly in early differentiation between BMD and DMD children under 10 years old with mild functional decline. In addition, the combined application of T1 and T2 facilitates early differential diagnosis of non–fat-infiltrated muscles between BMD and DMD.”

The study was limited by differing sample sizes between groups, as well as the potential for minor effects of daily activities on T1 or T2 measurements. Unrelated factors that may contribute to intramuscular fat infiltration, such as obesity, were also not accounted for. Additionally, most patients with DMD had received corticosteroids, and it is difficult to adjust for the effects of steroids on qMRI measurements. The study also used the traditional Dixon technique for MRI, which can perform FF quantification accurately but lacks T2* correction and could introduce slight T1 or T2 bias due to the relatively larger flip angle.

“Multiparametric MRI has demonstrated effective differential diagnostic capabilities for ambulatory children with DMD and BMD, including those under 10 years old with mild functional decline as defined by linearized NSAA scores,” the authors concluded. “In distinguishing between DMD and BMD, the FF is the preferred qMRI biomarker. Additionally, T1 and T2 can serve as important supplements to FF, particularly in the early stages of the disease.”

References

1. Peng F, Xu H, Xu T, et al. Multi‐parametric quantitative MRI in the early differential diagnosis of ambulatory children with Duchenne muscular dystrophy and Becker muscular dystrophy. Journal of Magnetic Resonance Imaging. Published online March 4, 2025. doi:10.1002/jmri.29755
2. Mercuri E, Bönnemann CG, Muntoni F. Muscular dystrophies. Lancet (London, England). 2019:394(10213):2025–2038. doi:10.1016/S0140-6736(19)32910-1