Visualising peripheral arterioles and venules through high-resolution and large-area photoacoustic imaging

Yoshiaki Matsumoto,Ken-Ichi Nagae,Takaki Sakurai,Itaru Tsuge,Takayuki Yagi,Tsuyoshi Shiina,Tomoko Ishii,Yoshihiro Ishida,Shigehiko Suzuki,Yasufumi Asao,Masako Kataoka,Shuichi Kobayashi,Aya Yoshikawa,Kaori Togashi,Hiroyuki Sekiguchi,Kenji Kabashima,Susumu Saito,Masakazu Toi,Masahiro Takada

doi:10.1038/s41598-018-33255-8

Yoshiaki Matsumoto, Ken-Ichi Nagae + Show 17 more

Open Access

https://doi.org/10.1038/s41598-018-33255-8

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Abstract

Photoacoustic (PA) imaging (PAI) has been shown to be a promising tool for non-invasive blood vessel imaging. A PAI system comprising a hemispherical detector array (HDA) has been reported previously as a method providing high morphological reproducibility. However, further improvements in diagnostic capability will require improving the image quality of PAI and fusing functional and morphological imaging. Our newly developed PAI system prototype not only enhances the PA image resolution but also acquires ultrasonic (US) B-mode images at continuous positions in the same coordinate axes. In addition, the pulse-to-pulse alternating laser irradiation shortens the measurement time difference between two wavelengths. We scanned extremities and breasts in an imaging region 140 mm in diameter and obtained 3D-PA images of fine blood vessels, including arterioles and venules. We could estimate whether a vessel was an artery or a vein by using the S-factor obtained from the PA images at two wavelengths, which corresponds approximately to the haemoglobin oxygen saturation. Furthermore, we observed tumour-related blood vessels around breast tumours with unprecedented resolution. In the future, clinical studies with our new PAI system will help to elucidate various mechanisms of vascular-associated diseases and events.

Highlights

Photoacoustic (PA) imaging (PAI) has been shown to be a promising tool for non-invasive blood vessel imaging
The current vascular imaging method used in the medical field requires the use of a contrast agent, and obtaining an image requires X-ray exposure or an expensive contrast magnetic resonance imaging (MRI) examination
The elementary design of PAI-04 inherited the design of the conventional prototype (PAI-03)[9,10,19] equipped with an hemispherical detector array (HDA) receiving PA signals

Summary

Introduction

Photoacoustic (PA) imaging (PAI) has been shown to be a promising tool for non-invasive blood vessel imaging. A blood vessel is a passageway for blood and plays a vital role in transporting various components, such as oxygen and nutrients, to each organ of the body Ailments such as diabetes, cardiovascular disease and collagen diseases, such as rheumatism, involve injury to the peripheral blood vessels. Photoacoustic (PA) tomography (PAT) is an imaging method that utilises the light absorption of haemoglobin for non-invasive blood vessel imaging[3]. Obtaining high-quality images is challenging because of the ‘limited view problem’ of PA phenomena[16] To resolve this problem, a PAT system comprising a hemispherical detector array (HDA) surrounding an object to be measured with a solid angle wider than that of a linear probe has been reported previously[17,18,19]. This study aims to outline the device configuration of our novel PA imaging system prototype, presents examples of in vivo images obtained using this device and elucidates its possible clinical applications

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