title: Hyperpolarized Helium-3 MRI of exercise-induced bronchoconstriction during challenge and therapy.
abstract: OBJECTIVE
  To investigate the utility of hyperpolarized He-3 MRI for detecting regional lung ventilated volume (VV) changes in response to exercise challenge and leukotriene inhibitor montelukast, human subjects with exercise induced bronchoconstriction (EIB) were recruited. This condition is described by airway constriction following exercise leading to reduced forced expiratory volume in 1 second (FEV1) coinciding with ventilation defects on hyperpolarized He-3 MRI.
  
  
  METHODS
  Thirteen EIB subjects underwent spirometry and He-3 MRI at baseline, postexercise, and postrecovery at multiple visits. On one visit montelukast was given and on two visits placebo was given. Regional VV was calculated in the apical/basilar dimension, in the anterior/posterior dimension, and for the entire lung volume. The whole lung VV was used as an end-point and compared with spirometry.
  
  
  RESULTS
  Postchallenge FEV1 dropped with placebo but not with treatment, while postchallenge VV dropped more with placebo than treatment. Sources of variability for VV included region (anterior/posterior), scan, and treatment. VV correlated with FEV1/ forced vital capacity (FVC) and forced expiratory flow between 25 and 75% of FVC and showed gravitational dependence after exercise challenge.
  
  
  CONCLUSIONS
  A paradigm testing the response of ventilation to montelukast revealed both a whole-lung and regional response to exercise challenge and therapy in EIB subjects.
authors.affiliation: Department of Medical Physics, University of Wisconsin, Madison, Wisconsin, USA.
authors.forename: Stanley J
authors.initials: SJ
authors.lastname: Kruger
authors.forename: David J
authors.initials: DJ
authors.lastname: Niles
authors.forename: Bernard
authors.initials: B
authors.lastname: Dardzinski
authors.forename: Amy
authors.initials: A
authors.lastname: Harman
authors.forename: Nizar N
authors.initials: NN
authors.lastname: Jarjour
authors.forename: Marcella
authors.initials: M
authors.lastname: Ruddy
authors.forename: Scott K
authors.initials: SK
authors.lastname: Nagle
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Francois
authors.forename: Ronald L
authors.initials: RL
authors.lastname: Sorkness
authors.forename: Ryan M
authors.initials: RM
authors.lastname: Burton
authors.forename: Alejandro
authors.initials: A
authors.lastname: Munoz del Rio
authors.forename: Sean B
authors.initials: SB
authors.lastname: Fain
mesh_terms: D000085:Acetates / Q000627:therapeutic use*; D000328:Adult; D001982:Bronchial Diseases / Q000175:diagnosis* / Q000188:drug therapy*; D001993:Bronchodilator Agents / Q000627:therapeutic use; D003251:Constriction, Pathologic / Q000175:diagnosis / Q000188:drug therapy; D003521:Cyclopropanes; D005080:Exercise Test; D005260:Female; D006371:Helium; D006801:Humans; D007554:Isotopes; D008176:Lung Volume Measurements / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011804:Quinolines / Q000627:therapeutic use*; D019275:Radiopharmaceuticals; D013440:Sulfides; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D000085:Acetates; D001993:Bronchodilator Agents; D003521:Cyclopropanes; D007554:Isotopes; D011804:Quinolines; D019275:Radiopharmaceuticals; D013440:Sulfides; D006371:Helium; C093875:montelukast
keywords: asthma; exercise; helium; imaging; therapy