title: Simultaneous MRI of lung structure and perfusion in a single breathhold.
abstract: OBJECTIVE
  To develop and demonstrate a breathheld 3D radial ultrashort echo time (UTE) acquisition to visualize co-registered lung perfusion and vascular structure.
  
  
  METHODS
  Nine healthy dogs were scanned twice at 3 Tesla (T). Contrast-enhanced pulmonary perfusion scans were acquired with a temporally interleaved three-dimensional (3D) radial UTE (TE = 0.08 ms) sequence in a breathhold (1 s time frames over a 33 s breathhold). The 3D breathheld volume was reconstructed into time-resolved perfusion datasets, and a composite vascular structure dataset. For structural comparison, a 5 min respiratory-gated 3D radial UTE scan was acquired. Data were analyzed by quantitative metrics and radiologist scoring.
  
  
  RESULTS
  Appropriate time-course of contrast was seen in all subjects. Right ventricle to aorta transit times were 7.4 ± 2.0 s. Relative lung enhancement was a factor of 8.4 ± 1.5. Radiologist scoring showed similarly excellent visualization of the pulmonary arteries to the subsegmental level in breathheld (94% of cases) and respiratory-gated (100% of cases) acquisitions (P = 0.33) despite the aggressive under sampling in the breathheld scan. Similarly, differentiation of lung tissue and airways was achieved by both acquisition methods.
  
  
  CONCLUSIONS
  A time-resolved 3D radial UTE sequence for simultaneous imaging of pulmonary perfusion and co-registered vascular structure is feasible.
authors.affiliation: School of Medicine and Public Health, Department of Medical Physics, Wisconsin, USA.
authors.forename: Laura C
authors.initials: LC
authors.lastname: Bell
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Johnson
authors.forename: Sean B
authors.initials: SB
authors.lastname: Fain
authors.forename: Andrew
authors.initials: A
authors.lastname: Wentland
authors.forename: Randi
authors.initials: R
authors.lastname: Drees
authors.forename: Rebecca A
authors.initials: RA
authors.lastname: Johnson
authors.forename: Grzegorz
authors.initials: G
authors.lastname: Bauman
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Francois
authors.forename: Scott K
authors.initials: SK
authors.lastname: Nagle
mesh_terms: D000818:Animals; D062485:Breath Holding; D003287:Contrast Media / Q000008:administration & dosage; D004285:Dogs; D005260:Female; D007089:Image Enhancement; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008168:Lung / Q000033:anatomy & histology* / Q000098:blood supply*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male
chemical_list: D003287:Contrast Media
keywords: 3D radial UTE for lung imaging; pulmonary perfusion; vascular structure