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The effect of unit, depth, and probe load on the reliability of muscle shear wave elastography: Variables affecting reliability of SWE
Author(s) -
Alfuraih Abdulrahman M.,
O'Connor Philip,
Hensor Elizabeth,
Tan Ai Lyn,
Emery Paul,
Wakefield Richard J.
Publication year - 2018
Publication title -
journal of clinical ultrasound
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.272
H-Index - 61
eISSN - 1097-0096
pISSN - 0091-2751
DOI - 10.1002/jcu.22534
Subject(s) - biceps , medicine , intraclass correlation , elastography , anatomy , confidence interval , nuclear medicine , biomedical engineering , orthodontics , ultrasound , radiology , clinical psychology , psychometrics
Purpose There is currently no standardized method for muscle shear wave elastography (SWE). The objective of this study was to investigate the effect of unit of measurement, depth, and probe load on the reliability of muscle SWE. Methods The vastus lateralis, biceps femoris, biceps brachii, and abductor digiti minimi muscles were scanned on 20 healthy participants. The SWE readings were measured in shear wave velocity (m/s) and Young's modulus (kPa). Three acquisitions of varying depths were acquired from vastus lateralis. Minimal probe load was compared with the use of a standoff gel layer. Three repeated measurements were acquired to assess reliability using intraclass correlations (ICC). Results The mean elasticity varied across muscle groups and ranged from 1.54 m/s for biceps femoris to 2.55 m/s for abductor digiti minimi (difference = 1.01 m/s [95% confidence interval, CI = 0.92, 1.10]). Reporting readings in meters per second resulted in higher ICC of 0.83 (0.65, 0.93) in comparison to 0.77 (0.52, 0.90) for kilopascal for the vastus lateralis muscle only. Variance increased proportionally with depth reaching 0.17 (equivalent to ±0.82 m/s) at 6 cm. Using a standoff gel decreased ICC to 0.63 (0.20, 0.84) despite similar mean elasticity readings to minimal probe load. Conclusions Different acquisition and technical factors may significantly affect the reliability of SWE in skeletal muscles. Readings acquired in the unit of shear wave velocity (m/s) from depths less than 4 cm using a minimal probe load without a standoff gel yielded the best reliability.