Quantitative muscle ultrasonography using textural analysis in amyotrophic lateral sclerosis

Abstract

Background: To analyze differences in grey level co-ocurrence matrix (GLCM) parameters, as assessed by muscle ultrasound (MUS), between amyotrophic lateral sclerosis (ALS) patients and healthy controls. To compare the diagnostic accuracy of these GLCM parameters with first order MUS parameters (echointensity, EI; echovariation, EV; and muscle thickness, MTh) in different muscle groups. Methods: Twenty-six patients with ALS and twenty-six healthy subjects underwent bilateral and transverse ultrasound of the biceps/brachialis, forearm flexor, quadriceps femoris and tibialis anterior muscle groups. MTh was measured with electronic callipers and EI, EV and GLCM were obtained using Image J (v.1.48) software. Sensitivity, specificity, likelihood ratios and area under the curve (AUC) were performed by logistic regression models and ROCcurves. Results: GLCM parameters showed reduced granularity in the muscles of ALS patients compared with the controls. Regarding the discrimination capacity, the best single diagnostic parameter in forearm flexors and quadriceps was GLCM and in biceps brachialis and tibialis anterior was EV. The respective combination of these two parameters with MTh resulted in the best AUC (over 90% in all muscle groups and close to the maximum combination model). Conclusions: The use of new textural parameters (EV and GLCM) combined with usual quantitative MUS variables are a promising biomarker in ALS.