武汉同济医院李小明 Diffusion tensor imaging in evaluation of thigh muscles in patients with polymyositis and dermatomyositis.

Br J Radiol. 2014 Nov;87（1043）:20140261. doi: 10.1259/bjr.20140261. Epub 2014 Sep 3.

Diffusion tensor imaging in evaluation of thigh muscles in patients with polymyositis and dermatomyositis.

Ai T¹, Yu K, Gao L, Zhang P, Goerner F, Runge VM, Li X.

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Abstract

OBJECTIVE:

To explore the diffusion tensor imaging （DTI） characteristics of thigh muscles in patients with polymyositis （PM） anddermatomyositis （DM）.

METHODS:

12 patients with known PM/DM and 10 healthy volunteers were enrolled in this study. Both DTI and conventional MR sequences were performed on both thighs of all subjects. Apparent diffusion coefficient （ADC）, fractional anisotropy （FA） and three eigenvalues were compared between the PM/DM group and the healthy group. One-way analysis of variance and Student's t-test were used for statistical analyses with a significance of p < 0.05.

RESULTS:

In the healthy group, the vastus intermedius muscle showed the highest ADC value and the gracilis （GA） muscle showed the lowest ADC value. These results were statistically significant when compared with other muscles （p < 0.05）. The GA, semi-tendinosus and semi-membranosus muscles showed higher FA values than the other three thigh muscles （p < 0.05）. The mean ADC value and three eigenvalues of oedematous muscles in the PM/DM group were higher on average and showed a statistically significant difference when compared with unaffected （non-oedematous muscles in patients） and normal muscles （p < 0.05）. There was no statistical difference in the mean FA value between oedematous and normal muscles. The mean ADC, FA and three eigenvalues in unaffected muscles （in patients） showed no statistical differences from those in normal muscles （p > 0.05）.

CONCLUSION:

DTI can be used to quantitatively evaluate the anisotropic diffusion characteristics of muscles in patients with PM/DM.

ADVANCES IN KNOWLEDGE:

A new application of DTI is proposed for inflammatory myopathies. The results show that ADC and the three eigenvalues were significantly different between diseased and normal muscles, a finding of potential value in both diagnosis and treatment monitoring of myopathies.

PMID: 25183381 PMCID: PMC4207168 DOI: 10.1259/bjr.20140261