title: Time-resolved three-dimensional pulmonary MR angiography and perfusion imaging with ultrashort repetition time.
abstract: OBJECTIVE
  The purpose of this study was to implement ultrafast, multiphase three-dimensional (3D) magnetic resonance (MR) angiography and perfusion imaging after bolus injection of contrast medium to generate preliminary validation of parameters in a pig model and to illustrate potential applications in patients with lung abnormalities.
  
  
  METHODS
  Five healthy volunteers, five patients, and three pigs underwent rapid, time-resolved pulmonary MR angiography and perfusion imaging on a 1.5-T MR imager. All patients had undergone correlative computed tomographic or conventional angiography. The pulse sequence was a 3D spin-warp, gradient-echo acquisition with a repetition time of 1.6 msec and an echo time of 0.6 msec. Each 3D acquisition lasted 2-3 seconds, and 8-16 sequential measurements were made in each study. Artificial pulmonary emboli were generated in pigs with gelatin sponge. All patients had diseases of the pulmonary circulation (as confirmed with other studies).
  
  
  RESULTS
  Multiphasic, time-resolved pulmonary parenchymal enhancement was demonstrated in all healthy subjects and animals. All segmental (n = 100) and subsegmental (n = 200) branches were identified in the healthy subjects. Perfusion deficits were clearly demonstrated in all pigs after gelatin embolization. Perfusion defects were identified in two patients with lung disease. Abnormalities of the pulmonary vasculature were clearly identified in the patient group.
  
  
  CONCLUSIONS
  Dynamic time-resolved 3D pulmonary MR angiography and perfusion imaging is feasible in humans as well as in animals. Induced perfusion deficits are identifiable after artificial embolization in pigs. Combined pulmonary MR angiography and parenchymal (perfusion) imaging may improve evaluation of the pulmonary circulation in a variety of conditions.
authors.affiliation: Department of Radiology, Northwestern University Medical School and Northwestern Memorial Hospital, 251 E Huron St, Feinberg 4-710, Chicago, IL 60611, USA.
authors.forename: James C
authors.initials: JC
authors.lastname: Carr
authors.forename: Gerhard
authors.initials: G
authors.lastname: Laub
authors.forename: Jie
authors.initials: J
authors.lastname: Zheng
authors.forename: F Scott
authors.initials: FS
authors.lastname: Pereles
authors.forename: J Paul
authors.initials: JP
authors.lastname: Finn
mesh_terms: D000328:Adult; D000368:Aged; D000818:Animals; D001013:Aorta, Thoracic / Q000000981:diagnostic imaging; D001157:Arterial Occlusive Diseases / Q000175:diagnosis; D001165:Arteriovenous Malformations / Q000175:diagnosis; D001706:Biopsy; D005260:Female; D006352:Heart Ventricles / Q000000981:diagnostic imaging; D006801:Humans; D021621:Imaging, Three-Dimensional; D008168:Lung / Q000098:blood supply / Q000000981:diagnostic imaging; D008171:Lung Diseases / Q000175:diagnosis; D018810:Magnetic Resonance Angiography / Q000379:methods; D008297:Male; D008875:Middle Aged; D010477:Perfusion / Q000379:methods*; D011651:Pulmonary Artery / Q000000981:diagnostic imaging / Q000473:pathology; D011652:Pulmonary Circulation / Q000502:physiology; D011667:Pulmonary Veins / Q000000981:diagnostic imaging / Q000473:pathology; D011856:Radiographic Image Enhancement; D013552:Swine; D013997:Time Factors; D014057:Tomography, X-Ray Computed