Technical Note: Contrast free angiography of the pulmonary vasculature in live mice using a laboratory x-ray source.
OBJECTIVE
In vivo imaging of the pulmonary vasculature in small animals is difficult yet highly desirable in order to allow study of the effects of a host of dynamic biological processes such as hypoxic pulmonary vasoconstriction. Here the authors present an approach for the quantification of changes in the vasculature.


METHODS
A contrast free angiography technique is validated in silico through the use of computer-generated images and in vivo through microcomputed tomography (μCT) of live mice conducted using a laboratory-based x-ray source. Subsequent image processing on μCT data allowed for the quantification of the caliber of pulmonary vasculature without the need for external contrast agents. These measures were validated by comparing with quantitative contrast microangiography in the same mice.


RESULTS
Quantification of arterial diameters from the method proposed in this study is validated against laboratory-based x-ray contrast microangiography. The authors find that there is a high degree of correlation (R = 0.91) between measures from microangiography and their contrast free method.


CONCLUSIONS
A technique for quantification of murine pulmonary vasculature without the need for contrast is presented. As such, this technique could be applied for longitudinal studies of animals to study changes to vasculature without the risk of premature death in sensitive mouse models of disease. This approach may also be of value in the clinical setting.
4Dx Limited, Melbourne 3000, Australia.
Chaminda R
CR
Samarage
4Dx Limited, Melbourne 3000, Australia and Department of Mechanical and Aerospace Engineering, Monash University, Melbourne 3800, Australia.
Richard
R
Carnibella
Department of Mechanical and Aerospace Engineering, Monash University, Melbourne 3800, Australia.
Melissa
M
Preissner
Department of Medicine and the Women's Guild Lung Institute, Cedars-Sinai Medical Center, Los Angeles, California 90048.
Heather D
HD
Jones
Department of Physiology, Monash University, Melbourne 3800, Australia; Monash Biomedical Imaging Facility Monash University, Melbourne 3800, Australia; and Australian Synchrotron, Melbourne 3168, Australia.
James T
JT
Pearson
4Dx Limited, Melbourne 3000, Australia and Department of Mechanical and Aerospace Engineering, Monash University, Melbourne 3800, Australia.
Andreas
A
Fouras
4Dx Limited, Melbourne 3000, Australia and Department of Mechanical and Aerospace Engineering, Monash University, Melbourne 3800, Australia.
Stephen
S
Dubsky
D000792:Angiography / Q000379:methods*; D000818:Animals; D005260:Female; D021621:Imaging, Three-Dimensional; D051379:Mice; D008807:Mice, Inbred BALB C; D011651:Pulmonary Artery / Q000000981:diagnostic imaging*; D011667:Pulmonary Veins / Q000000981:diagnostic imaging*; D055114:X-Ray Microtomography / Q000379:methods*