Assessment of Age-related Oxygenation Changes in Calf Skeletal Muscle by Photoacoustic Imaging: A Potential Tool for Peripheral Arterial Disease. (September 2019)

• Record Type: Journal Article
• Authors: Kirkham, Brooke M.; Schultz, Susan M.; Ashi, Khalid; Sehgal, Chandra M.
• Is Part Of: Ultrasonic imaging. Volume 41:Number 5(2019)
• Page Start: 290
• Page End: 300
• Publication Date: 2019-09
• Subjects: peripheral artery disease -- photoacoustic imaging -- oxygenation -- skeletal muscle; Diagnostic ultrasonic imaging -- Methodology -- Periodicals; Ultrasonic testing -- Periodicals; Ultrasonic imaging -- Periodicals; Ultrasonography -- Periodicals; Échographie -- Méthodologie -- Périodiques; Essais par ultrasons -- Périodiques; Imagerie ultrasonore -- Périodiques; 616.07543
• DOI: 10.1177/0161734619862287
• Languages: English
• ISSNs: 0161-7346

Abstract

Peripheral artery disease is often asymptomatic, and various imaging and nonimaging techniques have been used for assessment and monitoring treatments. This study is designed to demonstrate the ability of photoacoustic imaging to noninvasively determine changes in tissue oxygenation that occur in mice's hind limb skeletal muscle as they age. Mice from two age cohorts were scanned bilaterally with a pulsed laser. The photoacoustic signal was unmixed to generate a parametric map of estimated oxygen saturation and then overlaid on grayscale ultrasound images. Tissue oxygenation measured in young and old mice was compared. Photoacoustic imaging visually and quantitatively showed the decrease in skeletal muscle oxygenation that occurs with age. Percent tissue oxygenation decreased from 30.2% to 3.5% ( p < 0.05). This reduction corresponded to reduced fractional area of oxygenation, which decreased from 60.6% to 6.0% ( p < 0.05). The change in oxygenation capacity of the still active vascular regions was insignificant ( p > 0.05). Intrasubject, intra-, and interobserver comparisons showed low variability in measurements, exhibited by high regression and intraclass correlations exceeding 0.81 for all ages. The decrease in oxygenation detected by photoacoustic imaging paralleled the known oxygenation decrease observed in aging tissues, demonstrating that photoacoustic imaging can assess age-related changes in a mouse calf muscle. These intramuscular changes could potentially act as a strong diagnostic marker for peripheral artery disease. This study thus opens the doors for a novel, affordable, noninvasive method of evaluation free of radiation or exogenous material.