Magnetic resonance imaging pattern variability in dysferlinopathy

Abstract

The widespread use of magnetic resonance imaging (MRI) in the diagnosis of myopathies has made it possible to clarify the typical MRI pattern of dysferlinopathy. However, sufficient attention has not been given to the variability of MRI patterns in dysferlinopathy.

Materials and methods: Twenty-five patients with the clinical manifestations of dysferlinopathy were examined. For all patients, creatine phosphokinase levels were measured and molecular genetics were examined. In two patients, immunohistochemical examinations of muscle biopsies were performed. MRI scanning was included T2 multi-slice multi-echo, T1 weighted, T2 weighted and Short Tau Inversion Recovery T2 weighted sequences. Quantitative and semi-quantitative evaluations of fatty replacement and swelling of the muscles were undertaken.

Results: Variability in the MRI patterns was lowest in the pelvis and leg muscles and highest in the thigh muscles. Three main types of MRI patterns were distinguished: posterior-dominant (80%), anterior-dominant (16%), and diffuse (4%). Among patients with the anterior-dominant pattern, the collagen-like variant (4%), proximal variant (4%) and pseudo-myositis (8%) were separately distinguished.

Conclusions: Awareness of atypical MRI patterns in dysferlinopathy is important for increasing the efficiency of routine diagnostics and optimizing the search for causative gene mutations.

Keywords: LGMD2B; LGMDR2; MRI pattern; Miyoshi myopathy; T2-MSME; dysferlinopathy.

Figure 1.

Fatty replacement in the pelvis, thigh, and lower leg muscles of patients with limb-girdle muscular dystrophy recessive type 2, n = 25 (a, thigh muscles; b, lower leg muscles). The fatty degenerative changes were scored according to the Lamminen-Mercuri scale. The colors indicate the grades of the Lamminen-Mercuri scale, presented as a stacked bar chart. Average magnetic resonance imaging distribution pattern of fatty replacement in limb-girdle muscular dystrophy recessive type 2 muscles (scoring according to Lamminen-Mercuri) in the mid thigh (C) and mid calf muscles (D).

Figure 2.

The frequency and severity of edema in the muscles of the thighs (A) and lower legs (B) in patients with limb-girdle muscular dystrophy recessive type 2, n = 25.

Figure 3.

MRI (T1, Short Tau Inversion Recovery (STIR)) of the muscles of the pelvic girdle, thighs and legs of patient 1 with the Miyoshi phenotype (disease duration 24 years) (T1-weighted (WI) A, B, C; STIR D, E, F).

Figure 4.

MRI pattern of fatty muscle infiltration of the pelvic girdle, thighs and legs of patient 2 (T1-WI A, B, C; Short Tau Inversion Recovery (STIR) D, E, F). Note fibrotic changes in the distal semitendinosus muscle (images B and E, marked with arrows).

Figure 5.

MRI pattern of the distribution of fatty infiltration in the muscles of the pelvic girdle, thighs and lower legs in patient 3 with a disease duration of 1 year. (T1-WI A, B, C; Short Tau Inversion Recovery (STIR) D, E, F). Arrows indicate fibrosed muscles.

Figure 6.

Collagen-like MRI pattern of muscle damage in the pelvic girdle, thighs and legs of patient 4, a 35 year old with limb-girdle muscular dystrophy recessive type 2 (LGMDR2) and a disease duration of 5 years (A, B, C). The MRI pattern of fatty replacement in the thigh muscles of a 27-year-old patient with LGMD recessive type 1 (D); and patient B, a 47 year old with congenital Bethlem myopathy (E). T1-WI, weighted; STIR, Short Tau Inversion Recovery.

Figure 7.

MRI pattern of fatty replacement distribution in the muscles of the pelvic girdle, thighs and legs of patient 5, a 64-year-old female with a disease duration of 9 years (T1-WI A, B, C; Short Tau Inversion Recovery (STIR)-T2w D, E, F). Immunohistochemical study of muscle biopsy samples from patients 5 (64 years old) and patient 4 (35 years old). Normal membrane dysferlin staining is observable in the vastus lateralis of patient 5 using antibodies to dysferlin (G). Control (H). Western blot analysis showed a low level of dysferlin protein expression in patient 4 and a decrease in expression of more than 60% in patient 5 (I).

Figure 8.

MRI pattern of the distribution of fatty infiltration in the muscles of the pelvic girdle, thighs and lower legs of a 30-year-old patient with limb-girdle muscular dystrophy recessive type 2 and a disease duration of 11 years (T1-WI A, B, C, D; Short Tau Inversion Recovery (STIR) E, F, G, H).