Use of angle-independent M-mode sonography for assessment of diaphragm displacement

Sam R. Orde, Andrea J. Boon, Daniel G. Firth, Hector R. Villarraga, Hiroshi Sekiguchi

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


Objectives - Sonographic assessment of diaphragm displacement has conventionally been conducted with M-mode sonography via an anterior subcostal approach. This method is subject to measurement errors when diaphragm displacement is not in line with the M-mode plane. We aimed to compare measurements obtained by offline angle-independent (anatomic) M-mode sonography with conventional M-mode sonography. Methods - Fifty healthy adults were imaged with conventional and angle-independent M-mode sonography of the bilateral hemidiaphragms at 60% maximal inspiratory capacity using an inspiratory spirometer. Results - Left hemidiaphragm displacement was successfully imaged by conventional M-mode sonography in only 70% (n = 35), as lung expansion obscured imaging, whereas 92% (n = 46) were assessable by angle-independent M-mode sonography. All right hemidiaphragm displacement could be assessed. Conventional M-mode results were higher than angle-independent M-mode results on the right (mean ± SD, 4.9 ± 1.4 versus 4.6 ± 1.2 cm, respectively; P = .003) and left (5.4 ± 1.3 versus 4.6 ± 1.0 cm; P < .001). Displacement values were different for right versus left hemidiaphragms on conventional M-mode sonography (mean difference, 0.6 ± 0.2 cm; P = .005), with only mild agreement (R2 = 0.35; P < .001). There was no laterality seen in the diaphragm displacement on angle- independent M-mode sonography (mean difference, 0.1 ± 0.1 cm; P = .47), with good agreement (R2 = 0.76; P < .001). Conclusions - Angle-independent M-mode sonography leads to better visualization and assessment of the left hemidiaphragm. It records lower displacement than conventional M-mode sonography in the bilateral diaphragms, likely because of fewer orientation and translation errors. Future study is indicated to assess the clinical utility of angle-independent M-mode sonography in a population with diaphragm dysfunction.

Original languageEnglish (US)
Pages (from-to)2615-2621
Number of pages7
JournalJournal of Ultrasound in Medicine
Issue number12
StatePublished - Dec 1 2016


  • Diaphragm
  • M-mode sonography
  • Musculoskeletal ultrasound
  • Sonography

ASJC Scopus subject areas

  • Radiological and Ultrasound Technology
  • Radiology Nuclear Medicine and imaging


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