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Monitoring of wound healing progression is critical due to the risk of infection, non-healing wounds, or evolution towards a chronic state. Tissue vasculature is one of the most representative features reflecting healing status. This study explores the feasibility of vascular ultrasound imaging of open wounds and the extraction of vascular-related features in a longitudinal study. C57BL/6 mice received a 1 cm-diameter full-thickness wound on their dorsum and were imaged using ultrasound from the surgical day (Day 0) to 25 days post-wounding. The high frame rate, plane waves acquisitions with a 15 MHz transducer were postprocessed with Singular Value Decomposition (SVD) filtering to provide vascular information. Vascularity Index (VI) calculations showed an increased vascular signal in the wound from Day 2 post-wounding and were significantly higher from day 6 to day 10 post-wounding compared to Day 0 (p<0.05). VI values were back to the basal level after 3 weeks. In comparison, no significant difference was highlighted for the vascular signal in the peri-wound area. These results show that vascular ultrasound imaging can be applied to track vascular changes of open wounds during the healing process. This approach may also be extended to other types of wounds for detecting early signs likely to cause complications. • 1 cm diameter full thickness wounds in mice typically close after three weeks. • Ultrasound imaging can characterize vascular remodeling from open wounds. • Wound vascularization peaks after eight days before returning to baseline. • Vascular activity is confined within three millimeters from the wound epicenter. [ABSTRACT FROM AUTHOR]

Abstract: Shock wave therapy (SWT) refers to the use of focused shock waves for treatment of musculoskeletal indications including plantar fascitis and dystrophic mineralization of tendons and joint capsules. Measurements were made of a SWT device that uses a ballistic source. The ballistic source consists of a handpiece within which compressed air (1–4 bar) is used to fire a projectile that strikes a metal applicator placed on the skin. The projectile generates stress waves in the applicator that transmit as pressure waves into tissue. The acoustic fields from two applicators were measured: one applicator was 15 mm in diameter and the surface slightly convex and the second was 12 mm in diameter the surface was concave. Measurements were made in a water tank and both applicators generated a similar pressure pulse consisting of a rectangular positive phase (4 μs duration and up to 8 MPa peak pressure) followed by a predominantly negative tail (duration of 20 μs and peak negative pressure of −6 MPa), with many oscillations. The rise times of the waveforms were around 1 μs and were shown to be too long for the pulses to be considered shock waves. Measurements of the field indicated that region of high pressure was restricted to the near-field (20–40 mm) of the source and was consistent with the Rayleigh distance. The measured acoustic field did not display focusing supported by calculations, which demonstrated that the radius of curvature of the concave surface was too large to effect a focusing gain. Other SWT devices use electrohydraulic, electromagnetic and piezoelectric sources that do result in focused shock waves. This difference in the acoustic fields means there is potentially a significant mechanistic difference between a ballistic source and other SWT devices. (E-mail: robinc@bu.edu) [Copyright &y& Elsevier]