title: Ultrasonographic diaphragm thickness correlates with compound muscle action potential amplitude and forced vital capacity.
abstract: BACKGROUND
  Noninvasive evaluation of respiratory function in patients with various neuromuscular disorders is important for predicting life expectancy.
  
  
  METHODS
  We performed B-mode ultrasonography (USG) and nerve conduction studies in 37 patients (16 had amyotrophic lateral sclerosis; 11, myopathy; and 10, neuropathy) and 10 controls. USG of the diaphragm was performed in the supine position using a linear probe over the intercostal space at the anterior axillary line. Diaphragm muscle thickness was measured at end-expiration. The amplitude of diaphragm compound muscle action potentials (CMAP) was obtained by phrenic nerve stimulation with a surface electrode. Respiratory function was measured with standard pulmonary function tests including forced vital capacity (FVC).
  
  
  RESULTS
  Diaphragm thickness was significantly correlated with FVC (r = 0.74) and CMAP amplitude (r = 0.53).
  
  
  CONCLUSIONS
  Diaphragm USG is useful for objective evaluation of pulmonary function in neuromuscular disorders without requiring undue patient effort or cooperation.
authors.affiliation: Division of Neurology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chou-ku, Kobe City, Hyogo, 650-0017, Japan.
authors.forename: Yoshikatsu
authors.initials: Y
authors.lastname: Noda
authors.affiliation: Division of Neurology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chou-ku, Kobe City, Hyogo, 650-0017, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Sekiguchi
authors.affiliation: Division of Neurology, Kobe City Medical Center General Hospital, Kobe City, Hyogo, Japan.
authors.forename: Nobuo
authors.initials: N
authors.lastname: Kohara
authors.affiliation: Division of Neurology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chou-ku, Kobe City, Hyogo, 650-0017, Japan.
authors.forename: Fumio
authors.initials: F
authors.lastname: Kanda
authors.affiliation: Division of Neurology, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chou-ku, Kobe City, Hyogo, 650-0017, Japan.
authors.forename: Tatsushi
authors.initials: T
authors.lastname: Toda
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000328:Adult; D000368:Aged; D003964:Diaphragm / Q000000981:diagnostic imaging* / Q000294:innervation / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009431:Neural Conduction / Q000502:physiology*; D009468:Neuromuscular Diseases / Q000000981:diagnostic imaging / Q000503:physiopathology; D010791:Phrenic Nerve / Q000000981:diagnostic imaging / Q000502:physiology; D011446:Prospective Studies; D014463:Ultrasonography; D014797:Vital Capacity / Q000502:physiology*
keywords: diaphragm thickness; neuromuscular disorder; phrenic nerve; respiratory function; ultrasonography