Magnetic resonance imaging phenotyping of Becker muscular dystrophy.

Introduction: There is little information on magnetic resonance imaging (MRI) phenotypes of Becker muscular dystrophy (BMD). This study presents the MRI phenotyping of the upper and lower extremities of a large cohort of BMD patients.

Methods: In this retrospective study, MRI images of 33 BMD subjects were evaluated for severity, distribution, and symmetry of involvement.

Results: Teres major, triceps long head, biceps brachii long head, gluteus maximus, gluteus medius, vasti, adductor longus, adductor magnus, semitendinosus, semimembranosus, and biceps femoris muscles showed the highest severity and frequency of involvement. All analyzed muscles had a high frequency of symmetric involvement. There was significant variability of involvement between muscles within some muscle groups, most notably the arm abductors, posterior arm muscles, medial thigh muscles, and lateral hip rotators.

Conclusions: This study showed a distinctive pattern of involvement of extremity muscles in BMD subjects.