Muskelultraschall - ein sinnvolles Werkzeug bei der Diagnosestellung der amyotrophen Lateralsklerose

The modification of the El-Escorial criteria of 2008 (so-called Awaji-Shima criteria) has increased the value of electrophysiology in the diagnostics for amyotrophic lateral sclerosis. Fibrillations detected by electromyography and positive sharp waves as well as fasciculations in chronic neurogenically altered or clinically afflicted muscles are considered to be of pathological relevance in the determination of damage to the 2^nd motor neurons (abbreviated as MN). Beside electrophysiological examinations, sonographic examinations of muscles have attracted increasing interest in the past years. The combination of static and dynamic imaging provides possibilities that are not available by any other imaging processes of the musculature. Furthermore. the procedure is non-invasive and, above all, makes possible the in toto visualisation of muscle groups that are only difficultly accessible with electromyography. Although the detection of fasciculations by ultrasound has been possible for some time, improved technology and high-resolution ultrasound scanners of up to 18 MHz have now also made the recognition of fibrillations possible. B mode representations of the musculature with measurements of muscle volume, echogenicity and atrophy provide additional important information in all stages of the disease. Recently acquired results have demonstrated that sonography of muscles as supplement to EMG speeds up the diagnosis process and increases the diagnostic sensitivity. The present article is intended to provide an overview of the methods of muscle sonography as used in the diagnostics for amyotrophic lateral sclerosis.