title: Lung MRI and impairment of diaphragmatic function in Pompe disease.
abstract: BACKGROUND
  Pompe disease is a progressive metabolic myopathy. Involvement of respiratory muscles leads to progressive pulmonary dysfunction, particularly in supine position. Diaphragmatic weakness is considered to be the most important component. Standard spirometry is to some extent indicative but provides too little insight into diaphragmatic dynamics. We used lung MRI to study diaphragmatic and chest-wall movements in Pompe disease.
  
  
  METHODS
  In ten adult Pompe patients and six volunteers, we acquired two static spirometer-controlled MRI scans during maximum inspiration and expiration. Images were manually segmented. After normalization for lung size, changes in lung dimensions between inspiration and expiration were used for analysis; normalization was based on the cranial-caudal length ratio (representing vertical diaphragmatic displacement), and the anterior-posterior and left-right length ratios (representing chest-wall movements due to thoracic muscles).
  
  
  RESULTS
  We observed striking dysfunction of the diaphragm in Pompe patients; in some patients the diaphragm did not show any displacement. Patients had smaller cranial-caudal length ratios than volunteers (p < 0.001), indicating diaphragmatic weakness. This variable strongly correlated with forced vital capacity in supine position (r = 0.88) and postural drop (r = 0.89). While anterior-posterior length ratios also differed between patients and volunteers (p = 0.04), left-right length ratios did not (p = 0.1).
  
  
  CONCLUSIONS
  MRI is an innovative tool to visualize diaphragmatic dynamics in Pompe patients and to study chest-walland diaphragmatic movements in more detail. Our data indicate that diaphragmatic displacement may be severely disturbed in patients with Pompe disease.
authors.affiliation: Department of Neurology, Erasmus MC, Rotterdam, The Netherlands. s.wens@erasmusmc.nl.|Centre for Lysosomal and Metabolic Diseases, Erasmus MC-Sophia, Rotterdam, The Netherlands. s.wens@erasmusmc.nl.
authors.forename: Stephan C A
authors.initials: SC
authors.lastname: Wens
authors.affiliation: Department of Radiology, Erasmus MC, Rotterdam, The Netherlands. p.ciet@erasmusmc.nl.|Department of Pediatrics, Respiratory Medicine and Allergology, Erasmus MC-Sophia, Rotterdam, The Netherlands. p.ciet@erasmusmc.nl.|Department of Radiology, Beth Israel Deaconess Medical Center- Harvard Medical School, Boston, MA, USA. p.ciet@erasmusmc.nl.
authors.forename: Pierluigi
authors.initials: P
authors.lastname: Ciet
authors.affiliation: Department of Radiology, Erasmus MC, Rotterdam, The Netherlands. a.perezrovira@erasmusmc.nl.|Biomedical Imaging Group Rotterdam, Departments of Radiology and Medical Informatics, Erasmus MC, Rotterdam, The Netherlands. a.perezrovira@erasmusmc.nl.|Department of Pediatric Pulmonology, Erasmus MC-Sophia, Rotterdam, The Netherlands. a.perezrovira@erasmusmc.nl.
authors.forename: Adria
authors.initials: A
authors.lastname: Perez-Rovira
authors.affiliation: Department of Pediatric Pulmonology, Erasmus MC-Sophia, Rotterdam, The Netherlands. k.logie@erasmusmc.nl.
authors.forename: Karla
authors.initials: K
authors.lastname: Logie
authors.affiliation: Department of Pediatric Pulmonology, Erasmus MC-Sophia, Rotterdam, The Netherlands. Elizabeth.Salamon@health.wa.gov.au.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Salamon
authors.affiliation: Department of Radiology, Erasmus MC, Rotterdam, The Netherlands. p.wielopolski@erasmusmc.nl.
authors.forename: Piotr
authors.initials: P
authors.lastname: Wielopolski
authors.affiliation: Biomedical Imaging Group Rotterdam, Departments of Radiology and Medical Informatics, Erasmus MC, Rotterdam, The Netherlands. marleen.debruijne@erasmusmc.nl.|Department of Computer Science, University of Copenhagen, Copenhagen, Denmark. marleen.debruijne@erasmusmc.nl.
authors.forename: Marleen
authors.initials: M
authors.lastname: de Bruijne
authors.affiliation: Centre for Lysosomal and Metabolic Diseases, Erasmus MC-Sophia, Rotterdam, The Netherlands. m.kruijshaar@erasmusmc.nl.
authors.forename: Michelle E
authors.initials: ME
authors.lastname: Kruijshaar
authors.affiliation: Department of Radiology, Erasmus MC, Rotterdam, The Netherlands. h.tiddens@erasmusmc.nl.|Department of Pediatrics, Respiratory Medicine and Allergology, Erasmus MC-Sophia, Rotterdam, The Netherlands. h.tiddens@erasmusmc.nl.
authors.forename: Harm A W M
authors.initials: HA
authors.lastname: Tiddens
authors.affiliation: Department of Neurology, Erasmus MC, Rotterdam, The Netherlands. p.a.vandoorn@erasmusmc.nl.|Centre for Lysosomal and Metabolic Diseases, Erasmus MC-Sophia, Rotterdam, The Netherlands. p.a.vandoorn@erasmusmc.nl.
authors.forename: Pieter A
authors.initials: PA
authors.lastname: van Doorn
authors.affiliation: Centre for Lysosomal and Metabolic Diseases, Erasmus MC-Sophia, Rotterdam, The Netherlands. a.vanderploeg@erasmusmc.nl.|Department of Pediatrics, Division of Metabolic Diseases and Genetics, Erasmus MC-Sophia, Rotterdam, The Netherlands. a.vanderploeg@erasmusmc.nl.
authors.forename: Ans T
authors.initials: AT
authors.lastname: van der Ploeg
mesh_terms: D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D003964:Diaphragm / Q000473:pathology / Q000503:physiopathology*; D045853:Exhalation; D005260:Female; D005541:Forced Expiratory Volume; D006009:Glycogen Storage Disease Type II / Q000473:pathology / Q000503:physiopathology*; D006801:Humans; D001239:Inhalation; D008168:Lung / Q000473:pathology / Q000503:physiopathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D013147:Spirometry; D014797:Vital Capacity