Correlations between clinical and MRI measures were assessed in the patient group (Fig. 3). There was a significant negative correlation between the patients’ overall ROEM and the mean T2 relaxation time of the EOMs (rho = −0.89, p < 0.01). Mean EOM area did not correlate with disease duration or ROEM. Muscles graded as showing marked atrophy had significantly smaller relative cross sectional area (59 % of control value) than those graded as no (98 % control value) or mild (93 % control value) atrophy (p < 0.001). However, the difference in size between mild and no atrophy was not significant.
Fig. 3 Spearman correlations between clinical and quantitative MRI measures in patients with chronic progressive external ophthalmoplegia (A). A single mean value for each parameter was calculated in each patient for the common regions of interest (superior rectus, inferior rectus, medial rectus and lateral rectus). Range of eye movement (ROEM) correlated with T2 relaxation time. The cross-sectional area did not correlate with either ROEM or disease duration. Scatter plots are shown for T2 versus ROEM (B) and area versus ROEM (C)