Skeletal muscle analyses: Agreement between non-contrast and contrast CT scan measurements of skeletal muscle area and mean muscle attenuation

Anne van der Werf, Ingeborg M. Dekker, Martijn R. Meijerink, Nicolette J. Wierdsma, Marian A. E. de van der Schueren, Jacqueline A. E. Langius

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Low skeletal muscle area (SMA) and muscle radiation attenuation (MRA) have been associated with poor prognosis in various patient populations. Both non-contrast and contrast CT scans are used to determine SMA and MRA. The effect of the use of a contrast agent on SMA and MRA is unknown. Therefore, we investigated agreement between these two scan options. SMA and MRA of 41 healthy individuals were analysed on a paired non-contrast and contrast single CT scan, and agreement between paired scan results was assessed with use of Bland-Altman plots, intraclass correlation coefficients (ICCs), standard error of measurements (SEM) and smallest detectable differences at a 95% confidence level (SDD95). Analyses were stratified by tube voltage. Difference in SMA between non-contrast and contrast scans made with a different tube voltage was 7·0 ± 7·5 cm2; for scans made with the same tube voltage this was 2·3 ± 1·7 cm2. Agreement was excellent for both methods: ICC: 0·952, SEM: 7·2 cm2, SDD95: 19·9 cm2 and ICC: 0·997, SEM: 2·0 cm2, SDD95: 5·6 cm2, respectively. MRA of scans made with a different tube voltage differed 1·3 ± 11·3 HU, and agreement was poor (ICC: 0·207, SEM: 7·9 HU, SDD95: 21·8 HU). For scans made with the same tube voltage the difference was 6·7 ± 3·2 HU, and agreement was good (ICC: 0·682, SEM: 5·3 HU, SDD95: 14·6 HU). In conclusion, SMA and MRA can be slightly influenced by the use of contrast agent. To minimise measurement error, image acquisition parameters of the scans should be similar.

Original languageEnglish
Pages (from-to)366-372
JournalClinical physiology and functional imaging
Issue number3
Publication statusPublished - May 2018


  • computed tomography
  • contrast agent
  • muscle density
  • muscle mass
  • single slice

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