Abstract-Text (inkl. Referenzen)

Objectives:

To evaluate differences in qMRI parameters of muscle diffusion tensor imaging (mDTI), fat-fraction (FF) and water-T2 time in leg muscles of calpainopathy patients (LGMD R1/D4) compared to healthy controls, to correlate those findings to clinical parameters and to evaluate if qMRI parameters show muscle degeneration in not-yet fatty infiltrated muscles.

Methods:

We evaluated eight thigh and seven calf muscles of 19 calpainopathy patients and 19 healthy matched controls. MRI scans were performed on a 3T MRI including a mDTI, T2 mapping and mDixonquant sequence. Clinical assessment was done with manual muscle testing, patient questionnaires (ACTIVLIM, NSS) as well as gait analysis.

Results:

Average FF was significantly different in all muscles compared to controls (p<0.001). In muscles with less than 8% FF a significant increase of FA (p<0.005) and decrease of RD (p<0.004) was found in high-risk muscles of calpainopathy patients. Water T2 times were increased within the low- and intermediate-risk muscles (p≤0.045) but not in high-risk muscles (p=0.062). Clinical assessments correlated with qMRI values.

Conclusion:

A good correlation of FF and diffusion metrics to clinical assessments were found. Diffusion metrics and T2 values are promising candidates to serve as a sensitive early and non-invasive biomarker in non-fat-infiltrated muscles in calpainopathies.