Technical Note: Contrast free angiography of the pulmonary vasculature in live mice using a laboratory x-ray source

• Published in: Medical physics (Lancaster) 2016-11, Vol.43 (11), p.6017-6023
• Main Authors: Samarage, Chaminda R., Carnibella, Richard, Preissner, Melissa, Jones, Heather D., Pearson, James T., Fouras, Andreas, Dubsky, Stephen
• Format: Article
• Language: English
• Subjects: Angiography; Angiography - methods; Animals; Biological material, e.g. blood, urine; Haemocytometers; blood vessels; Computed tomography; Computerised tomographs; computerised tomography; contrast free; diagnostic radiography; Digital computing or data processing equipment or methods, specially adapted for specific applications; Female; Image analysis; Image data processing or generation, in general; image reconstruction; Imaging, Three-Dimensional; lab‐source; lung; Lungs; Medical image contrast; medical image processing; Medical image reconstruction; Medical image segmentation; Mice; Mice, Inbred BALB C; Pulmonary Artery - diagnostic imaging; pulmonary vasculature; Pulmonary Veins - diagnostic imaging; QUANTITATIVE IMAGING AND IMAGE PROCESSING; Reconstruction; X-Ray Microtomography - methods; x‐ray; X‐ray imaging
• ISSN: 0094-2405; 2473-4209
• DOI: 10.1118/1.4964794

Purpose: 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.