研究者詳細 - 相磯　貞和

相磯　貞和（アイソ　サダカズ）

Aiso, Sadakazu

写真a

所属（所属キャンパス）: 医学部（三田）

職名: 名誉教授

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Quantitative evaluation of lower limb varicose veins using photoacoustic imaging

Urano M., Nagae K., Matsuda S., Matsubara K., Yagi T., Imanishi N., Aiso S., Obara H., Jinzaki M.

Journal of Medical Ultrasonics 51 （ 3 ） 507 - 516 2024年07月

ISSN 13464523

　概要を見る

Purpose: Varicose veins in the lower extremities are dilated subcutaneous varicose veins with a diameter of ≥ 3 mm, caused by increased venous pressure resulting from backflow of blood due to venous valve insufficiency (Gloviczki in Handbook of venous disorders: guidelines of the American venous forum, Hodder Arnold, London, 2009). When diagnosing varicose veins, the shape and thickness of the blood vessels should be accurately visualized in three dimensions. In this study, we investigated a new method for numerical evaluation of vascular morphology related to varicose veins in the lower extremities, using a photoacoustic imaging (PAI) system, which can acquire high-resolution and three-dimensional images noninvasively. Methods: Nine patients with varicose veins participated in the study, and their images were captured using an optical camera and PAI system. We visualized the vascular structure, created a blood presence density (BPD) heat map, and examined the correlation between BPD and location of varicose veins. Results: The obtained photoacoustic (PA) images demonstrated the ability of this method to visualize vessels ranging from as small as 0.2 mm in diameter to large, dilated vessels in three dimensions. Furthermore, the study revealed a correlation between the high-density part of the BPD heat map generated from the PAI images and the presence of varicose veins. Conclusion: PAI is a promising technique for noninvasive and accurate diagnosis of varicose veins in the lower extremities. By providing valuable information on the morphology and hemodynamics of the varicose veins, PAI may facilitate their early detection and treatment.
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Visualization of intradermal blood vessel structures by dual-wavelength photoacoustic microscopy and characterization of three-dimensional construction of livedo-racemosa in cutaneous polyarteritis nodosa

Sujino K., Tanese K., Saito Y., Kuramoto J., Iwazaki H., Ida T., Aiso S., Imanishi N., Kajita H., Fukuda K., Amagai M., Tanikawa A.

Journal of Dermatological Science 114 （ 2 ） 71 - 78 2024年05月

ISSN 09231811

　概要を見る

Background: Photoacoustic microscopy is expected to have clinical applications as a noninvasive and three-dimensional (3D) method of observing intradermal structures. Objective: Investigate the applicability of a photoacoustic microscope equipped with two types of pulsed lasers that can simultaneously recognize hemoglobin and melanin. Methods: 16 skin lesions including erythema, pigmented lesions, vitiligo and purpura, were analyzed to visualize 3D structure of melanin granule distribution and dermal blood vessels. 13 cases of livedo racemosa in cutaneous polyarteritis nodosa (cPN) were further analyzed to visualize the 3D structure of dermal blood vessels in detail. Vascular structure was also analyzed in the biopsy specimens obtained from tender indurated erythema of cPN by CD34 immunostaining. Results: Hemoglobin-recognition signal clearly visualized the 3D structure of dermal blood vessels and melanin-recognition signal was consistently reduced in vitiligo. In livedo racemosa, the hemoglobin-recognition signal revealed a relatively thick and large reticular structure in the deeper layers that became denser and finer toward the upper layers. The numerical analysis revealed that the number of dermal blood vessels was 1.29-fold higher (p<0.05) in the deeper region of the lesion than that of normal skin. The CD34 immunohistochemical analysis in tender indurated erythema revealed an increased number of dermal vessels compared with normal skin in 88.9% (8/9) of the cases, suggesting that vascular network remodeling had occurred in cPN. Conclusion: The photoacoustic system has an advantage in noninvasively detecting dermal blood vessel structures that are difficult to recognize by two-dimensional histopathology specimen examination and is worth evaluating in various skin diseases.
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Reliability-Aware Restoration Framework for 4D Spectral Photoacoustic Data

Liao W., Subpa-Asa A., Asano Y., Zheng Y., Kajita H., Imanishi N., Yagi T., Aiso S., Kishi K., Sato I.

IEEE Transactions on Pattern Analysis and Machine Intelligence 45 （ 12 ） 15445 - 15461 2023年12月

ISSN 01628828

　概要を見る

Spectral photoacoustic imaging (PAI) is a new technology that is able to provide 3D geometric structure associated with 1D wavelength-dependent absorption information of the interior of a target in a non-invasive manner. It has potentially broad applications in clinical and medical diagnosis. Unfortunately, the usability of spectral PAI is severely affected by a time-consuming data scanning process and complex noise. Therefore in this study, we propose a reliability-aware restoration framework to recover clean 4D data from incomplete and noisy observations. To the best of our knowledge, this is the first attempt for the 4D spectral PA data restoration problem that solves data completion and denoising simultaneously. We first present a sequence of analyses, including modeling of data reliability in the depth and spectral domains, developing an adaptive correlation graph, and analyzing local patch orientation. On the basis of these analyses, we explore global sparsity and local self-similarity for restoration. We demonstrated the effectiveness of our proposed approach through experiments on real data captured from patients, where our approach outperformed the state-of-the-art methods in both objective evaluation and subjective assessment.
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High-resolution photoacoustic 3D imaging system for animal experiments using a hemispherical detector array

Asao Y., Nagae K., Sekiguchi H., Aiso S., Watanabe S., Sato M., Kizaka-Kondoh S., Yagi T.

Progress in Biomedical Optics and Imaging - Proceedings of SPIE 12379 2023年

ISSN 16057422

　概要を見る

A photoacoustic 3D imaging system for animal experiments was made. This system is special because it has a hemispherical detector array. To test its performance, we used a chart from the field of optics as a sample. We checked the whole imaging range using the ISO 12233 chart, which is used to test digital camera images. We found that there was no distortion in the xy-plane and the system had high resolution. We also tested it using a high image quality mode with a different scanning sequence. In this study, live albino mice with white hairs were anesthetized and photographed. Using hair removal cream, we were able to visualize the vascular network throughout their bodies, including blood vessels in organs such as the liver and kidneys. The smallest vessels we were able to visualize were less than 0.1 mm in diameter. We used photoacoustic (PA) images to relatively estimate the oxygen saturation of the mice's blood at two different wavelengths, which we refer to as the S-factor. By analyzing the PA images, we were able to estimate the arterial and venous systems of the whole body, as well as the difference in S-factor between the two systems within the liver. When the mice were euthanized and examined post-mortem, we observed that the S-factor of the whole body decreased and the difference in S-factor between the two systems within the liver was lost.
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In Vivo Label-Free Observation of Tumor-Related Blood Vessels in Small Animals Using a Newly Designed Photoacoustic 3D Imaging System

Asao Y., Nagae K., Miyasaka K., Sekiguchi H., Aiso S., Watanabe S., Sato M., Kizaka-Kondoh S., Nakajima Y., Kishi K., Yagi T.

Ultrasonic Imaging 44 （ 2-3 ） 96 - 104 2022年05月

ISSN 01617346

　概要を見る

Photoacoustic (PA) technology can be used for non-invasive imaging of blood vessels. In this paper, we report on our prototype PA imaging system with a newly designed ultrasound sensor and its visualization performance of microvascular in animal. We fabricated an experimental system for animals using a high-frequency sensor. The system has two modes: still image mode by wide scanning and moving image mode by small rotation of sensor array. Optical test target, euthanized mice and rats, and live mice were used as objects. The results of optical test target showed that the spatial resolution was about two times higher than that of our conventional prototype. The image performance in vivo was evaluated in euthanized healthy mice and rats, allowing visualization of detailed blood vessels in the liver and kidneys. In tumor-bearing mice, different results of vascular induction were shown depending on the type of tumor and the method of transplantation. By utilizing the video imaging function, we were able to observe the movement of blood vessels around the tumor. We have demonstrated the feasibility of the system as a less invasive animal experimental device, as it can acquire vascular images in animals in a non-contrast and non-invasive manner.
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KOARA（リポジトリ）収録論文等【表示／非表示】

D-セリン/ラセメース系による形態形成調節機序の包括的検討

相磯, 貞和

科学研究費補助金研究成果報告書 2011年

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研究発表【表示／非表示】

単球系培養細胞からのinterleukin-8産生における活性化第X因子の関与

藤島清太郎，相磯貞和，山口佳寿博，相川直樹

第43回日本呼吸器学会総会,

2003年03月
,
ポスター発表
'ラット放射線肺臓炎モデルにおけるMDC,TARC発現の検討'

井上卓，藤島清太郎，大久保泰之，余語由里香，相磯貞和，久保敦司，山口佳寿博

第43回日本呼吸器学会総会,

2003年03月
,
口頭発表（一般）
ラット放射線肺臓炎モデルにおけるMDC，TARC発現の検討

井上卓，藤島清太郎，大久保泰之，余語由里香，相磯貞和，久保敦司，山口佳寿博

43回日本呼吸器学会総会,

2003年03月
,
口頭発表（一般）
肺動脈血管内皮細胞のTGFb，FGF遺伝子発現に対するCCケモカインの影響

余語由里香，藤島清太郎，井上卓，相磯貞和，相川直樹，山口佳寿博

43回日本呼吸器学会総会,

2003年03月
,
口頭発表（一般）
'肺動脈内皮細胞のTGFβ,FGF遺伝子発現に対するCCケモカインの影響'

余語由里香，藤島清太郎，井上卓，相磯貞和，相川直樹，山口佳寿博

第43回日本呼吸器学会総会,

2003年03月
,
ポスター発表