title: Preferential changes of skeletal muscle echogenicity in myotonic dystrophy type 1.
abstract: In myotonic dystrophy type 1 (DM1), weakness of distal limb muscles affects quality of life. Non-invasive evaluation of muscular involvement by muscle sonography could be useful for characterizing muscle-specific involvement.
  
  
  
  Sonography of the lower leg and forearm was performed in 19 patients with DM1 and 10 control subjects. The mean echo intensities (EIs) of seven limb muscles were obtained by computer-assisted histogram analysis and compared within DM1 according to the overall clinical severity.
  
  
  
  The EIs of the muscles were significantly higher in DM1 than in the controls (P < 0.01), except for the soleus (P = 0.4). Comparison of adjacent muscles showed the following: (i) greater EIs in flexor digitorum profundus than flexor carpi ulnaris (P < 0.01) and flexor digitorum superficialis (P = 0.02), and (ii) greater EIs in the medial head of the gastrocnemius than the soleus (P < 0.00001). In a subgroup analysis of DM1 according to the modified Rankin Scale (mRS), the more severe subgroup (mRS = 4-5) had lower mean EIs than the less severe subgroup (mRS from 1-3) (P = 0.01) in the flexor digitorum superficialis but not in other muscles.
  
  
  
  Preferential high echogenicity in the medial gastrocnemius and deep finger flexors is suggestive of DM1. Muscle echogenicity is not generally related to functional dysfunction in DM1.
authors.affiliation: Department of Neurology, Tokushima University, Tokushima, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Takamatsu
authors.affiliation: Faculty of Medicine - Student Laboratory, Tokushima University, Tokushima, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Sogawa
authors.affiliation: Department of Neurology, Tokushima University, Tokushima, Japan.
authors.forename: H
authors.identifier: 0000-0002-5357-5081
authors.initials: H
authors.lastname: Nodera
authors.affiliation: Department of Neurology, Tokushima Hospital, Tokushima, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Hashiguchi
authors.affiliation: Department of Neurology, Tokushima University, Tokushima, Japan.|Department of Neurology, Tokushima Hospital, Tokushima, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Osaki
authors.affiliation: Department of Internal Medicine, Tokushima Hospital, Tokushima, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Saito
authors.affiliation: Department of Neurology, Tokushima University, Tokushima, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Mori
authors.affiliation: Department of Neurology, Tokushima University, Tokushima, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Izumi
authors.affiliation: Department of Neurology, Tokushima University, Tokushima, Japan.
authors.forename: R
authors.initials: R
authors.lastname: Kaji
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D005385:Fingers / Q000000981:diagnostic imaging; D005542:Forearm / Q000000981:diagnostic imaging; D006225:Hand / Q000000981:diagnostic imaging; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging*; D009223:Myotonic Dystrophy / Q000000981:diagnostic imaging*; D011788:Quality of Life; D014463:Ultrasonography; D055815:Young Adult
keywords: echogenicity; gastrocnemius; myotonic dystrophy type 1; skeletal muscle; sonography