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Intramuscular dissociation of echogenicity in the triceps surae characterizes sporadic inclusion body myositis
Author(s) -
Nodera H.,
Takamatsu N.,
Matsui N.,
Mori A.,
Terasawa Y.,
Shimatani Y.,
Osaki Y.,
Maruyama K.,
Izumi Y.,
Kaji R.
Publication year - 2016
Publication title -
european journal of neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.881
H-Index - 124
eISSN - 1468-1331
pISSN - 1351-5101
DOI - 10.1111/ene.12899
Subject(s) - medicine , forearm , polymyositis , inclusion body myositis , dermatomyositis , biceps , echogenicity , triceps surae muscle , myositis , flexor carpi ulnaris , anatomy , radiology , ultrasound , elbow , ulnar nerve
Background and purpose Differential diagnosis of sporadic inclusion body myositis (s‐ IBM ) and polymyositis ( PM )/dermatomyositis ( DM ) is difficult and can affect proper disease management. Detection of heterogeneous muscular involvement in s‐ IBM by muscle sonography could be a unique diagnostic feature. Methods Sonography of the lower leg and forearm was performed in patients with s‐ IBM , PM / DM and control subjects ( n = 11 each). Echo intensities ( EI s) of the adjacent muscles [medial head of the gastrocnemius versus soleus and the flexor digitorum profundus ( FDP ) versus flexor carpi ulnaris ( FCU )] were scored by three blinded raters. The mean EI s of these muscles were compared using computer‐assisted histogram analysis. Results Both evaluation methods showed high echoic signals in the gastrocnemius of patients with s‐ IBM . EI s were significantly different between the gastrocnemius and soleus in patients with s‐ IBM , but not in those with DM / PM and the controls. In the forearm, although the EI of the FDP was higher in the s‐ IBM group than in the other groups, the EI differences between the FDP and FCU did not differ significantly between disease groups. The difference in area under the curves to differentiate between s‐ IBM and DM / PM was greatest between the gastrocnemius−soleus EI s (0.843; P = 0.006). Conclusions High echoic signals in the medial gastrocnemius compared with those of the soleus are suggestive of s‐ IBM over PM / DM .