MRI and muscle signal intensities in alcoholics compared with control subjects

To evaluate by magnetic resonance imaging (MRI) the difference in muscle signal intensities between alcoholics and control subjects.

Thirty-four healthy subjects and 46 alcohol-dependent individuals were assessed. MRI was carried out using a low-field magnet (0.2 Tesla) and a limb-dedicated coil. The presence of muscle changes was evaluated by measuring signal intensities at the medial (MG) and lateral heads of the gastrocnemius muscle by T1-/T2-weighted and gradient-echo short tau inversion recovery sequences. The mean signal intensities of the two sample groups were compared by ANCOVA with age as a covariate. In the alcohol-dependent group, correlations between signal intensities and plasma levels of muscular and hepatic enzymes, in addition to years of high-risk consumption and lifetime dose of ethanol consumed, were assessed. The mean signal intensities were also compared with the different degrees of pain by ANOVA.

Compared with healthy subjects, the alcohol-dependent group had mean higher signal intensities in both gastrocnemius heads in all sequences. The difference in the MG in T2-weighted sequences was significant (F = 48.28, p < 0.01). A modest correlation between the years of high-risk consumption and the signal intensity was found in T2-weighted sequences in the MG (r = 0.288, p = 0.057), whereas a correlation with the lifetime dose consumed was not found. Significant correlations between signal intensities and plasma levels of muscular and hepatic enzymes were not found. There were also no significant group differences on different degrees of pain.

MRI was shown to be a sensitive, well-tolerated, and inexpensive procedure capable of detecting changes in signal intensities in the muscles of alcoholics. This technique could be included among other diagnostic tools for alcoholic myopathy with further improvements and if the signal alterations can be corroborated by biopsy evidence.