title: Skeletal muscle ultrasonography: Visual versus quantitative evaluation.
abstract: In this study, we compared the sensitivity and specificity of visual versus quantitative evaluation of skeletal muscle ultrasound in children suspected of having a neuromuscular disorder (NMD). Ultrasonography (US) scans of four muscles (biceps brachii, forearm flexors, quadriceps femoris, anterior tibial muscle) were made in 76 children. All images were visually evaluated using the Heckmatt criteria and quantitatively evaluated with computer-assisted grey-scale analysis of muscle echo intensity. Visual evaluation could achieve a sensitivity up to 71%, with a specificity of 92%. With quantification, a sensitivity of 87% accompanied by a specificity of 67% was found, but other diagnostic values could be achieved, depending on the cut-off point. Quantification resulted in a higher interobserver agreement (kappa 0.86) compared with visual evaluation (kappa 0.53). We conclude that quantification of echo intensity is a more objective and accurate method. Because it can achieve higher sensitivities, it is better-suited for the screening task in the diagnostic phase of children with a NMD.
authors.affiliation: Department of Clinical Neurophysiology, Institute of Neurology, Nijmegen, The Netherlands. s.pillen@cukz.umcn.nl
authors.forename: Sigrid
authors.initials: S
authors.lastname: Pillen
authors.forename: Mieke
authors.initials: M
authors.lastname: van Keimpema
authors.forename: Rutger A J
authors.initials: RA
authors.lastname: Nievelstein
authors.forename: Aad
authors.initials: A
authors.lastname: Verrips
authors.forename: Wilma
authors.initials: W
authors.lastname: van Kruijsbergen-Raijmann
authors.forename: Machiel J
authors.initials: MJ
authors.lastname: Zwarts
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D007223:Infant; D008297:Male; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging*; D009135:Muscular Diseases / Q000000981:diagnostic imaging; D009468:Neuromuscular Diseases / Q000000981:diagnostic imaging*; D015588:Observer Variation; D011446:Prospective Studies; D012372:ROC Curve; D012680:Sensitivity and Specificity; D014463:Ultrasonography