Motion-compensated noninvasive periodontal health monitoring using handheld and motor-based photoacoustic-ultrasound imaging systems

Abstract

Simultaneous visualization of the teeth and periodontium is of significant clinical interest for image-based monitoring of periodontal health. We recently reported the application of a dual-modality photoacoustic-ultrasound (PA-US) imaging system for resolving periodontal anatomy and periodontal pocket depths in humans. This work utilized a linear array transducer attached to a stepper motor to generate 3D images via maximum intensity projection. This prior work also used a medical head immobilizer to reduce artifacts during volume rendering caused by motion from the subject (e.g., breathing, minor head movements). However, this solution does not completely eliminate motion artifacts while also complicating the imaging procedure and causing patient discomfort. To address this issue, we report the implementation of an image registration technique to correctly align B-mode PA-US images and generate artifact-free 2D cross-sections. Application of the deshaking technique to PA phantoms revealed 80% similarity to the ground truth when shaking was intentionally applied during stepper motor scans. Images from handheld sweeps could also be deshaken using an LED PA-US scanner. In ex vivo porcine mandibles, pigmentation of the enamel was well-estimated within 0.1 mm error. The pocket depth measured in a healthy human subject was also in good agreement with our prior study. This report demonstrates that a modality-independent registration technique can be applied to clinically relevant PA-US scans of the periodontium to reduce operator burden of skill and subject discomfort while showing potential for handheld clinical periodontal imaging.

Monitoring peripheral hemodynamic response to changes in blood pressure via photoacoustic imaging

“…The use of motion compensation and deep-learning algorithms to reduce noise and align frames could help map perfusion and oxygenation of the tissue. [64, 65] Future work will look to map tissue oxygenation in real time.…”

Monitoring peripheral hemodynamic response to changes in blood pressure via photoacoustic imaging

“…Since we used a handheld scanner for all scans, it is difficult to generate 3D maps of the imaging area even though the system is capable to do so. The use of motion compensation and deep-learning algorithms to reduce noise and align frames could help map perfusion and oxygenation of the tissue [64] , [65] . Future work will look to map tissue oxygenation in real time.…”

A more compact photoacoustic imaging system to detect periodontitis

“…Figs. 1(a) and 1(b) compare the three different transducers available in our lab for periodontal imaging including the 9 MHz hockey stick transducer CL15-7, 20 MHz transducer L22-14vX [35], and 40 MHz transducer LZ-550 [24,25]. The three transducers have different shapes.…”