title: Clinical aspects of the apparent diffusion coefficient in 3He MRI: results in healthy volunteers and patients after lung transplantation.
abstract: OBJECTIVE
  To measure the apparent diffusion coefficient (ADC) after inhalation of hyperpolarized (3)He in healthy volunteers and lung transplant recipients, and demonstrate the gravity dependence of ADC values.
  
  
  METHODS
  Six healthy volunteers, 10 patients after single-lung transplantation, and six patients after double-lung transplantation were examined at 1.5T during inspiration and expiration. The inhalation of 300 mL of hyperpolarized (3)He was performed with a computer-controlled delivery device. A two-dimensional fast low-angle shot (FLASH) sequence measured the (3)He diffusive gas movement. From these data the ADC was calculated.
  
  
  RESULTS
  The mean ADC was 0.143 cm(2)/second in healthy individuals, 0.162 cm(2)/second in transplanted healthy lungs, and 0.173 cm(2)/second in rejected transplanted lungs, whereas it was 0.216 cm(2)/second in native fibrotic lungs and 0.239 cm(2)/second in emphysematous lungs. The difference in mean ADC values among healthy lungs, healthy transplanted lungs, and native diseased lungs was significant (P < 0.001). In inspiration the healthy volunteers showed higher ADC values in the anterior than in the posterior parts of the lungs. In expiration this gradient doubled.
  
  
  CONCLUSIONS
  An anterior-posterior (A/P) gradient was found in inspiration and expiration in healthy lungs. Healthy, transplanted, and native diseased lungs had significantly different mean ADC values. From our preliminary results, (3)He MRI appears to be sensitive for detecting areas of abnormal ventilation in transplanted lungs.
authors.affiliation: Department of Radiology, Johannes Gutenberg University, Mainz, Germany. andrea.bink@kgu.de
authors.forename: Andrea
authors.initials: A
authors.lastname: Bink
authors.forename: Gorden
authors.initials: G
authors.lastname: Hanisch
authors.forename: Andrea
authors.initials: A
authors.lastname: Karg
authors.forename: Annette
authors.initials: A
authors.lastname: Vogel
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Katsaros
authors.forename: Eckhard
authors.initials: E
authors.lastname: Mayer
authors.forename: Klaus K
authors.initials: KK
authors.lastname: Gast
authors.forename: Hans-Ulrich
authors.initials: HU
authors.lastname: Kauczor
mesh_terms: D000280:Administration, Inhalation; D000328:Adult; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006371:Helium / Q000008:administration & dosage; D006801:Humans; D007091:Image Processing, Computer-Assisted; D016040:Lung Transplantation; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011653:Pulmonary Diffusing Capacity; D011656:Pulmonary Emphysema / Q000503:physiopathology; D011658:Pulmonary Fibrosis / Q000503:physiopathology
chemical_list: D006371:Helium