Abstract 253: Vibrational Photoacoustic Imaging of Lipid in Murine Abdominal Aortic Aneurysms and Atherosclerosis

• Published in: Arteriosclerosis, thrombosis, and vascular biology Vol. 35; no. suppl_1
• Main Authors: Sangha, Gurneet S, Phillips, Evan H, Li, Rui, Cheng, Ji-Xin, Goergen, Craig J
• Format: Journal Article
• Language: English
• Published: 01-05-2015
• ISSN: 1079-5642; 1524-4636
• DOI: 10.1161/atvb.35.suppl_1.253

Abstract only Vibrational Photoacoustic Tomography (VPAT) is a novel imaging modality that uses pulsed laser light to generate an acoustic signal, making it ideal to obtain structural and compositional information. These characteristics allow detection of lipid distribution in diseased aortae by overlaying ultrasound (40 MHz transducer) and VPAT lipid signal (Fig. 1A). We used VPAT to test the hypothesis that arterial remodeling of suprarenal AAAs cause less lipid accumulation in the false lumen compared to other regions prone to atherosclerosis. To induce AAAs, osmotic minipumps were subcutaneously implanted in the backs of apolipoprotein E-deficient mice (n=4; 25±4.7 weeks old) to deliver 1000 ng/kg/min angiotensin II for 28 days. Aortae were imaged in situ, 21 days after AAA diagnosis, using VPAT at 1100 nm for blood (Fig. 1B) and 1210 nm for lipid (Fig. 1C) in a long-axis view. We quantified lipid and blood signal in the false lumen and the aortic wall proximal and distal to the AAAs. We observed a two-fold increase in lipid signal distal to the AAA (p<0.05) and small increase in lipid signal proximal to the AAA (p>0.05), likely due to atherosclerosis in these regions (AAA: 34.1±8.4 AU; distal: 68.5±19.4 AU; proximal: 56.7±9.7 AU). Blood signal was relatively constant along the vessel (AAA: 43.5±17.4 AU; distal: 40.2±28.2 AU; proximal: 27.8±17 AU). The aortae of these animals are prone to atherosclerosis, consistent with VPAT images and previous histological data. Interestingly, our findings show that while blood signal did not vary with location, lipid signal was reduced in the false lumen of these dissecting AAAs compared to other regions. These results suggest that VPAT may be useful to quantify atherosclerosis development, a disease becoming more prevalent with the current increase in obesity and diabetes.