Reliability and responsiveness of musculoskeletal ultrasound in subjects with and without spinal cord injury

Abstract

Rehabilitation after spinal cord injury (SCI) aims to preserve the integrity of the paralyzed musculoskeletal system. The suitability of ultrasound (US) for delineating training-related muscle/tendon adaptations after SCI is unknown. The purpose of this study was to quantify within- and between-operator reliability for US and to determine its responsiveness to post-training muscle/tendon adaptations in SCI subjects. Two novice operators and one experienced operator obtained sonographic images of the vastus lateralis, patellar tendon, soleus, and Achilles tendon from seven SCI subjects and 16 controls. For control subjects, within-operator concordance (ICC [3,1]) ranged from 0.58 to 0.95 for novice operators and exceeded 0.86 for the experienced operator. Between-operator concordance (ICC [2,1]) ranged from 0.62 to 0.74. Ultrasound detected muscle hypertrophy (p < 0.05) following electrical stimulation training in subjects with SCI (responsiveness) but did not detect differences in tendon thickness. These error estimates support the utility of US in future post-SCI training studies.

Copyright © 2010 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Figures

Figure 1

(A) For patellar tendon imaging, the probe was positioned in the transverse plane 3cm distal to the inferior pole of the patella. (B) Patellar tendon axial images. The dotted line in B denotes the tendon borders. (C) For longitudinal images of the vastus lateralis, the probe was positioned at 50% of femur length as determined by palpation of bony landmarks (depicted in A). Muscle thickness was measured orthogonal to the superficial fascia plane, in the interval denoted by arrows. The shadow of a transducer-mounted plastic strip (dotted line in C) denoted the location of the 50% landmark.

Figure 2

(A) For soleus images, the probe was positioned at 30% of tibia length in the mid-sagittal plane. (B) Sagittal image of soleus. Muscle thickness was measured orthogonal to the superficial fascia plane, in the interval denoted by arrows. The shadow of a transducer-mounted plastic strip (dotted line in B) denoted the location of the 30% landmark. (C) For Achilles tendon axial images, the probe was positioned in the axial plane 3cm proximal to the insertion of the tendon on the calcaneus (depicted in A). The dotted line in C denotes the tendon borders.

Figure 3

Mean (SD) non-SCI muscle and tendon dimensions (bars), compared to values obtained from the untrained limbs of SCI subjects (horizontal lines).

Figure 4

Representative images of trained and untrained vastus lateralis muscle for SCI subject S4 (top) trained and untrained Achilles tendon for subject S3 (bottom). AD = adipose tissue, VL = vastus lateralis, VI = vastus intermedius.

Figure 5

Percent difference between trained and untrained limbs for subjects who trained one soleus (n=3, left panel) and for subjects who trained one quadriceps (n=4, right panel). Dotted lines represent the experienced operator’s percent CV for sonographic measurement of that structure. Overall, muscle thickness was significantly increased in the trained limbs (p = 0.05) while the overall tendon thickness was not significantly changed with training (p = 0.43).