Towards in vivo photoacoustic imaging of vulnerable plaques in the carotid artery.

Jan-Willem Muller,Richard Lopata,Peter Brands,Roy van Hees,Marcel Rutten,Min Wu,Marc van Sambeek,Pierre Boutouyrie

doi:10.1364/boe.430064

Abstract

The main indicator for endarterectomy is the grade of stenosis, which results in severe overtreatment. Photoacoustic imaging (PAI) can provide patient-specific assessment of plaque morphology, and thereby vulnerability. A pilot study of PAI on carotid plaques in patients (n=16) was performed intraoperatively with a hand-held PAI system. By compensating for motion, the photoacoustic (PA) signal-to-noise ratio (SNR) could be increased by 5 dB in vivo. PA signals from hemorrhagic plaques had different characteristics compared to the signals from the carotid blood pool. This study is a key step towards a non-invasive application of PAI to detect vulnerable plaques.

Highlights

Cerebrovascular accidents are the second cause of death, and the third cause of disability worldwide [1]
With a fast, fully integrated hand-held laser-diode based PA/US probe, we aim to demonstrate the capability of Photoacoustic imaging (PAI) to image plaques with intraplaque hemorrhages in human, by performing the first pilot clinical study of PAI in patients during carotid endarterectomy (CEA)
To improve the PA signal-to-noise ratio (SNR) for in vivo imaging, we propose an motion corrected averaging (MCA) method based on speckle tracking

Summary

Introduction

Cerebrovascular accidents (stroke) are the second cause of death, and the third cause of disability worldwide [1]. Stroke occurs due to interruption or severe reduction of blood supply to the brain. A common cause of stroke is the rupture of a vulnerable plaque in one of the carotid arteries, which may lead to migration of thrombi or plaque material that obstruct distal arteries in the brain [2]. The grade of carotid stenosis is widely used to assess the risk of (recurrent) stroke, which is routinely estimated by duplex US. It is reported that 9 symptomatic or even 19 asymptomatic patients need to be operated to prevent one stroke in a 5 year time span [3,4], indicating a severe overtreatment with the current diagnosis. A more effective patient-specific risk assessment is a strong, unmet, clinical need

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