Assessment of regional lung function impairment in airway obstruction and pulmonary embolic dogs with combined noncontrast electrocardiogram-gated perfusion and gadolinium diethylenetriaminepentaacetic acid aerosol magnetic resonance images.
OBJECTIVE
To define regional function impairment in airway obstruction (AO) and pulmonary embolic (PE) dogs with a combination study of noncontrast electrocardiogram (ECG)-gated perfusion and gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA) aerosol magnetic resonance (MR) images.


METHODS
After acquisition of multiphase fast-spin-echo (FSE) MR images during cardiac cycles in 14 AO dogs and 19 PE dogs, ECG-gated perfusion-weighted (PW) images were obtained by subtraction between two-phase images of the minimum lung signal intensity (SI) during systole and maximum SI during diastole. Each dog subsequently inhaled Gd-DTPA aerosol for 20 minutes, and subtracted Gd-DTPA aerosol images were obtained from precontrast and maximally enhanced images. ECG-gated PW images were compared with intravenous Gd-DTPA-enhanced pulmonary arterial perfusion phase (PAPP) images.


RESULTS
ECG-gated PW images were consistent with Gd-DTPA-enhanced PAPP images in all dogs, with significant correlations in the affected-to-unaffected lung perfusion ratios (P < 0.005). Gd-DTPA aerosol images showed sufficient and uniform enhancement in the unaffected lungs. In all the AO areas, these combined images showed the matched perfusion and aerosol deposition defects. These images showed perfusion defects without aerosol deposition defects in the relatively small embolized areas, but showed the matched defects in the widely embolized areas probably due to hypoxic bronchial constriction.


CONCLUSIONS
The combination MR studies may be acceptable for noninvasively defining regionally impaired lung function in AO and PE.
Ogasawara
Nobuhiko
N
Department of Radiology, Yamaguchi University School of Medicine, Ube, Yamaguchi, Japan.
Suga
Kazuyoshi
K
Kawakami
Yasuhiko
Y
Yamashita
Tomio
T
Zaki
Mohammed
M
Matsunaga
Naofumi
N
D000280:Administration, Inhalation; D000336:Aerosols; D000402:Airway Obstruction / Q000473:pathology / Q000503:physiopathology*; D000818:Animals; D003287:Contrast Media / Q000008:administration & dosage*; D004285:Dogs; D004562:Electrocardiography; D019786:Gadolinium DTPA / Q000008:administration & dosage; D007275:Injections, Intravenous; D008168:Lung / Q000473:pathology / Q000503:physiopathology*; D008279:Magnetic Resonance Imaging / Q000379:methods; D009200:Myocardial Contraction; D011655:Pulmonary Embolism / Q000473:pathology / Q000503:physiopathology*; D013382:Subtraction Technique
D000336:Aerosols; D003287:Contrast Media; D019786:Gadolinium DTPA