title: Combined MR proton lung perfusion/angiography and helium ventilation: potential for detecting pulmonary emboli and ventilation defects.
abstract: Three-dimensional (3D) perfusion imaging allows the assessment of pulmonary blood flow in parenchyma and main pulmonary arteries simultaneously. MRI using laser-polarized (3)He gas clearly shows the ventilation distribution with high signal-to-noise ratio (SNR). In this report, the feasibility of combined lung MR angiography, perfusion, and ventilation imaging is demonstrated in a porcine model. Ultrafast gradient-echo sequences have been used for 3D perfusion and angiographic imaging, in conjunction with the use of contrast agent injections. 2D multiple-section (3)He imaging was performed subsequently by inhalation of 450 ml of hyperpolarized (3)He gas. The MR techniques were examined in a series of porcine models with externally delivered pulmonary emboli and/or airway occlusions. With emboli, perfusion deficits without ventilation defects were observed; airway occlusion resulted in matched deficits in perfusion and ventilation. High-resolution MR angiography can unambiguously reveal the location and size of the blood emboli. The combination of the three imaging methods may provide complementary information on abnormal lung anatomy and function.
authors.affiliation: Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, Missouri 63110, USA. zhengj@mir.wustl.edu
authors.forename: Jie
authors.initials: J
authors.lastname: Zheng
authors.forename: Jason C
authors.initials: JC
authors.lastname: Leawoods
authors.forename: Mark
authors.initials: M
authors.lastname: Nolte
authors.forename: Dmitriy A
authors.initials: DA
authors.lastname: Yablonskiy
authors.forename: Pamela K
authors.initials: PK
authors.lastname: Woodard
authors.forename: Gerhardt
authors.initials: G
authors.lastname: Laub
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Gropler
authors.forename: Mark S
authors.initials: MS
authors.lastname: Conradi
mesh_terms: D000402:Airway Obstruction / Q000175:diagnosis*; D000818:Animals; D005240:Feasibility Studies; D006371:Helium / Q000493:pharmacokinetics; D021621:Imaging, Three-Dimensional; D007554:Isotopes; D018810:Magnetic Resonance Angiography; D008279:Magnetic Resonance Imaging / Q000379:methods*; D011655:Pulmonary Embolism / Q000175:diagnosis*; D012123:Pulmonary Ventilation / Q000502:physiology; D013552:Swine; D014692:Ventilation-Perfusion Ratio
chemical_list: D007554:Isotopes; D006371:Helium