Pulmonary perfusion quantification with flow-sensitive inversion recovery (FAIR) UTE MRI in small animal imaging.
Blood perfusion in lung parenchyma is an important property for assessing lung function. In small animals, its quantitation is limited even with radioactive isotopes or dynamic contrast-enhanced MRI techniques. In this study, the feasibility flow-sensitive alternating inversion recovery (FAIR) for the quantification of blood flow in lung parenchyma in free breathing rats at 7 T has been investigated. In order to obtain sufficient signal from the short T2* lung parenchyma, a 2D ultra-short echo time (UTE) Look-Locker read-out has been implemented. Acquisitions were segmented to maintain acquisition time within an acceptable range. A method to perform retrospective respiratory gating (DC-SG) has been applied to investigate the impact of respiratory movement. Reproducibilities within and between sessions were estimated, and the ability of FAIR-UTE to identify the decrease of lung perfusion under hyperoxic conditions was tested. The implemented technique allowed for the visualization of lung parenchyma with excellent SNR and no respiratory artifact even in ungated acquisitions. Lung parenchyma perfusion was obtained as 32.54 ± 2.26 mL/g/min in the left lung, and 34.09 ± 2.75 mL/g/min in the right lung. Application of retrospective gating significantly but minimally changes the perfusion values, implying that respiratory gating may not be necessary with this center-our acquisition method. A decrease of 10% in lung perfusion was found between normoxic and hyperoxic conditions, proving the feasibility of the FAIR-UTE approach to quantify lung perfusion changes.
Core Facility Small Animal MRI, 89081 Ulm, University, Albert-Einstein-Allee 23, 89081 Ulm, Germany.
Marta
M
Tibiletti
In-Vivo Imaging Laboratory, Target Discovery Research, Boehringer Ingelheim Pharma, Birkendorfer Strasse 65, 88397 Biberach an der Riss, Germany.
Andrea
A
Bianchi
In-Vivo Imaging Laboratory, Target Discovery Research, Boehringer Ingelheim Pharma, Birkendorfer Strasse 65, 88397 Biberach an der Riss, Germany.
Detlef
D
Stiller
University Hospital of Ulm, Internal Medicine II, Ulm, Germany.
Volker
V
Rasche
D000818:Animals; D001783:Blood Flow Velocity / Q000502:physiology*; D005240:Feasibility Studies; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D018810:Magnetic Resonance Angiography / Q000379:methods* / Q000662:veterinary*; D008297:Male; D011651:Pulmonary Artery / Q000033:anatomy & histology / Q000502:physiology*; D011652:Pulmonary Circulation / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted; D013113:Spin Labels
D013113:Spin Labels
FAIR; UTE; arterial spin labeling; lung imaging; lung perfusion; ultra-short echo time