Visualization of the diaphragm muscle with ultrasound improves diagnostic accuracy of phrenic nerve conduction studies

Muscle Nerve. 2014 May;49(5):669-75. doi: 10.1002/mus.24059. Epub 2014 Apr 8.

Abstract

Introduction: Evaluation of phrenic neuropathy (PN) with phrenic nerve conduction studies (PNCS) is associated with false negatives. Visualization of diaphragmatic muscle twitch with diaphragm ultrasound (DUS) when performing PNCS may help to solve this problem.

Methods: We performed bilateral, simultaneous DUS-PNCS in 10 healthy adults and 12 patients with PN. The amplitude of the diaphragm compound muscle action potential (CMAP) (on PNCS) and twitch (on DUS) was calculated.

Results: Control subjects had <38% side-to-side asymmetry in twitch amplitude (on DUS) and 53% asymmetry in phrenic CMAP (on PCNS). In the 12 patients with PN, 12 phrenic neuropathies were detected. Three of these patients had either significant side-to-side asymmetry or absolute reduction in diaphragm movement that was not detected with PNCS. There were no cases in which the PNCS showed an abnormality but the DUS did not.

Conclusions: The addition of DUS to PNCS enhances diagnostic accuracy in PN.

Keywords: diaphragm ultrasound; nerve conduction studies; phrenic nerve conduction study; phrenic neuropathy; ultrasound.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Action Potentials / physiology
  • Adult
  • Aged
  • Case-Control Studies
  • Diaphragm / diagnostic imaging*
  • Diaphragm / innervation
  • Electrodiagnosis / methods*
  • Electromyography
  • Female
  • Humans
  • Male
  • Middle Aged
  • Neural Conduction / physiology*
  • Peripheral Nervous System Diseases / diagnosis*
  • Peripheral Nervous System Diseases / diagnostic imaging
  • Peripheral Nervous System Diseases / physiopathology
  • Phrenic Nerve / diagnostic imaging
  • Phrenic Nerve / physiopathology*
  • Retrospective Studies
  • Ultrasonography