Muscle MRI in Myotonic Dystrophy Type 1 with Foot Drop

Abstract

The purpose of this study was to investigate the relationship of muscle MRI findings and gait disturbance in myotonic dystrophy type 1 (DM1) patients. Thirteen patients with DM1 were evaluated by manual muscle strength test and muscle MRI of the lower limb. All DM1 patients presenting with foot drop showed high intensity signals in the tibialis anterior muscles on T1-weighted imaging (p < 0.001). The patients presenting with gait disturbance showed high intensity signals in the semimembranosus, vastus intermedius and gastrocnemius medialis muscles, too. Disturbance of the gastrocnemius lateralis muscles was mild in all DM1 patients. The patients without gait disturbance showed no abnormalities, especially in tibialis anterior muscles on muscle MRI. Muscle MRI is useful for the detection of pathological muscles in DM1 patients with gait disturbance.

Characteristic MRI findings of upper limb muscle involvement in myotonic dystrophy type 1

“…Several studies have demonstrated lower limb muscle involvement in DM1 patients [10][11][12][13]; however, the detailed distribution of upper limb muscle involvement has not been reported previously.…”

Muscle MRI of the Upper Extremity in the Myotonic Dystrophy Type 1

“…Diagnosis of DM1 was based upon clinical features, family history, genetic studies, electromyography, and muscle biopsy. The patients who had not undergone genetic analysis had typical clinical features of DM1 and a family history of genetically confirmed DM1 (patients 16,19), a family history of congenital DM1 in her sons (patient 17), or typical histology of DM1 in the muscle [2] and family history of typical DM1 in his son (patient 8).…”

“…Myotonic discharge was observed in all 17 of the patients examined. The biceps brachii muscle was biopsied in patients 2, 3, 5, and 8 as previously described [2] . Biopsied sections were immediately frozen and thin sections were stained by hematoxylin-eosin and Gomori trichrome.…”

“…3 a; tables 1 , 2 ) showed typical histopathological findings, including central nuclei and variation of fiber size ( fig. 3 b; table 2 ) [2,10] . Sarcoplasmic mass and nuclear clumps were observed in some fibers ( fig.…”

“…muscle disturbances of the lower extremities in myotonic dystrophy has been investigated using CT [6] or MRI [2,[7][8][9][10] . However, to our knowledge, only one previous report has evaluated the MRI findings of the upper extremity muscles in DM1 patients [11] .…”