Cover story: Photoacoustic characteristics of lipid-rich plaques under ultra-low temperature and formaldehyde treatment
At: 2018/3/20 16:14:50 by admin

Photoacoustic characteristics oflipid-rich plaques under ultra-low temperature and formaldehyde treatment

Cardiovascular diseases are the number one cause of deathworldwide, amongwhich, atherosclerosis is the fundamental pathology. Intravascularphotoacoustic imaging (IVPAI), a newly developed non-destructive imagingtechnology, is of great importance for atherosclerotic plaque study byproviding both structure and lipid component information. Comparative studywith histology is pivotal to verify the accuracy of IVPAI.


When a biological tissue is excited by the pulse laser, it generates ultrasonic signals that will be detected and recorded. The structure and the optical-absorptiondistribution of the tissue can be visualized by reconstructing the ultrasonic signalswith a back projection algorithm.Therefore, the anatomical images obtained by photoacoustic imaging possess innateadvantages of high contrast, high resolution and satisfactory penetration depth.These merits shed light on the application of IVPAI on atherosclerotic plaqueidentification


To date, most of IVPAI studies involve samples stored informaldehyde or under ultra-low temperature, both of which might alter thephotoacoustic characteristics of the artery, cause bias on the resultsexplanation and affect the pre-clinically translational research on photoacousticimaging. Therefore, estimation of effects posed by these two treatments onphotoacoustic characteristics of artery is extremely important.


Researchers from a joint research team of Qilu Hospital ofShandong University and South China Normal University made an improvement of thepreviously reported IVPAI imaging system to enable simultaneous photoacousticand ultrasound imaging of blood vessels. Then they compared the IVPAI resultsbefore and after ultra-low temperature or formaldehyde treatments with histologythe golden standard, to validate the effects they made on plaque photoacousticfeatures. The researchers found that both treatments have little effect on photoacousticcharacteristics of the artery samples. Lipid ratios pre- and post-ultra-low temperaturetreatment were 0.334±0.130 vs. 0.329±0.122 (p=0.299).The ratios pre- and post- formaldehyde treatment were 0.317±0.045 vs.0.316±0.040 (p=0.854). All theseIVPAI derived lipid ratios correlated highly with histological results. Thiswork has been published in Chinese Optics Letters, Volume 16, No. 3, 2018 (MingjunXu et al.,Photoacousticcharacteristics of lipid-rich plaques under ultra-low temperature andformaldehyde treatment).


Associate Professor Pengfei Zhang and Professor Sihua Yang,directors of the joint research group, believed that these results verified theaccuracy of intravascular photoacoustic imaging technology. Moreover, thediameter of this improved IVPAI imaging catheter is only 1.00 mm. Their work laida solid foundation for in vivo experiments and pre-clinical photoacousticexperiments in the future.


Based on these findings, further work will be focused on translationalresearch from ex vivo to in vivo, and application of IVPAI in monitoring the developmentor regression of atherosclerotic plaques.

Graphic description:

The research team enables simultaneousphotoacoustic and ultrasound imaging of blood vessels by improvingintravascular photoacoustic imaging system. The diameter of this imaging probeis only 1.00 mm, which lays the foundation for in vivo experiments.

Fig.2 The group photo

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