Evaluation of diaphragm thickening by diaphragm ultrasonography: a reproducibility and a repeatability study

Iacopo Cappellini*, Fabio Picciafuochi, Maurizio Bartolucci, Simona Matteini, Gianni Virgili, Chiara Adembri

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


Purpose: We have focused on the two-dimensional (B-mode) and the time-motion (M-mode) analysis of the zone of apposition to determine the reliability of diaphragm ultrasonography in the clinical environment. Methods: Ten healthy volunteers were enrolled and studied by three operators with different skills in ultrasonography. For every volunteer, each operator acquired three images of the diaphragm for each side, both in B-mode and in M-mode. Then a fourth operator calculated the thickening fraction (TF), by means of the formula TF = (TEI − TEE)/TEE (TEI is the thickness at end inspiration and TEE the thickness at end expiration). Afterwards, intraclass correlation coefficients (ICCs) were computed on TF to establish reproducibility and repeatability both in the B- and M-modes. An ICC ≤ 0.3 was considered acceptable. Results: Both B-mode (ICCs 0.16–0.26) and M-mode (ICCs 0.10–0.15) were sufficiently repeatable to assess TF, except in the case of B-mode for the less experienced operator (ICCs B-mode 0.20–0.32). Reproducibility was moderate to good among the operators with ICCs much narrower for the M-mode (0.13–0.14). Conclusions: The results of our study have shown that diaphragm ultrasound is repeatable and reproducible when carried out by a radiologist or an intensivist with a basic curriculum in ultrasonography. The method is more accurate when using the M-mode for less experienced operators, and in this case, repeatability and reproducibility are not sufficient to make clinical decisions. No TF value lower than 36% was obtained using both techniques. This suggests the existence of a cut-off value that could be used as an initial tool to discriminate healthy subjects from those affected by diaphragmatic dysfunction. Clinical trial registration: EUDRACT 2015-004635-12.

Original languageEnglish
JournalJournal of Ultrasound
Early online date01 May 2020
Publication statusEarly online date - 01 May 2020
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2020, Società Italiana di Ultrasonologia in Medicina e Biologia (SIUMB).

Copyright 2020 Elsevier B.V., All rights reserved.


  • Diaphragm ultrasonography
  • Repeatability

ASJC Scopus subject areas

  • Internal Medicine
  • Radiology Nuclear Medicine and imaging


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