Prediction of thigh skeletal muscle mass using dual energy x-ray absorptiometry compared to magnetic resonance imaging after spinal cord injury

J Spinal Cord Med. 2019 Sep;42(5):622-630. doi: 10.1080/10790268.2019.1570438. Epub 2019 Feb 1.

Abstract

Objectives: A rapid decline in lean mass (LM), fat-free mass (FFM) and increased intramuscular fat (IMF) predispose persons with spinal cord injury (SCI) to chronic medical conditions including dyslipidemia, insulin resistance, type 2 diabetes mellitus and cardiovascular disease. (1) To determine the relationship between dual energy x ray absorptiometry (DXA) and gold standard magnetic resonance imaging (MRI) LM values; (2) to develop predictive equations based on this relationship for assessing thigh LM in persons with chronic SCI. Study Design: Cross-sectional predicational design. Settings: Clinical research medical center. Participants: Thirty-two men with chronic (>1 y post-injury) motor complete SCI. Methods: Participants completed total body DXA scans to determine thigh LM and were compared to measurements acquired from trans-axial MRI. Outcome measures: MRI was used to measure whole muscle mass (MMMRI-WM), absolute muscle mass (MMMRI-ABS) after excluding IMF, and knee extensor muscle mass (MMMRI-KE). DXA was used to measure thigh LM (LMDXA) and (FFMDXA). To predict MMMRI-KE, LMDXA was multiplied by 0.52 and yielded LMDXA-KE. Results: LMDXA predicted MMMRI-WM [r2 = 0.90, standard error of the estimate (SEE) = 0.23 kg, P < 0.0001] and MMMRI-ABS (r2 = 0.82, SEE = 0.28 kg, P < 0.0001). LMDXA-KE predicted MMMRI-KE (r2 = 0.78, SEE = 0.16 kg, P < 0.0001). Conclusion: DXA measurements revealed an acceptable agreement with the gold standard MRI and may be a viable alternative for assessing thigh skeletal muscle mass after SCI.

Keywords: Dual energy x-ray absorptiometry; Lean mass; Magnetic resonance imaging; Spinal cord injury.

Publication types

  • Clinical Trial
  • Comparative Study
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Absorptiometry, Photon / methods
  • Absorptiometry, Photon / standards*
  • Adult
  • Female
  • Humans
  • Magnetic Resonance Imaging / methods
  • Magnetic Resonance Imaging / standards*
  • Male
  • Middle Aged
  • Muscle, Skeletal / diagnostic imaging*
  • Spinal Cord Injuries / diagnostic imaging*
  • Thigh / diagnostic imaging*