Quantitative evaluation of lower limb varicose veins using photoacoustic imaging.

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.

In Vivo Label-Free Observation of Tumor-Related Blood Vessels in Small Animals Using a Newly Designed Photoacoustic 3D Imaging System.

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.

Real-time 3D Photoacoustic Visualization System with a Wide Field of View for Imaging Human Limbs.

A breast-specific photoacoustic imaging (PAI) system prototype equipped with a hemispherical detector array (HDA) has been reported as a promising system configuration for providing high morphological reproducibility for vascular structures in living bodies. To image the vasculature of human limbs, a newly designed PAI system prototype (PAI-05) with an HDA with a higher density sensor arrangement was developed. The basic device configuration mimicked that of a previously reported breast-specific PAI system.

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

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.

Photoacoustic mammography capable of simultaneously acquiring photoacoustic and ultrasound images.

We have constructed a prototype photoacoustic mammography system (PAM-02) capable of simultaneously acquiring photoacoustic (PA) and ultrasound (US) images. Each PA, US, and fused PA/US image can be acquired over a wide area of the breast using the scanning module of a US transducer, a PA detector, and optical prisms. The resolution of the PA images exhibits improvement from 2 to 1 mm compared to images acquired using our previous prototype.

Small calcification depiction in ultrasound B-mode images using decorrelation of echoes caused by forward scattered waves.

Purpose: The purpose of this study is to propose a novel method to depict small calcifications in ultrasound B-mode images using decorrelation of forward scattered waves with no decrease in the frame rate.

Methods: Since the waveform of an ultrasound pulse changes when it passes through a calcification location, the echo waveform from regions behind the calcification is quite different from that without a calcification. This indicates that the existence of a calcification is predictable based upon the waveform difference between adjacent scan lines by calculating cross-correlation coefficients.