ABSTRACT
Background@#Lymphaticovenular anastomosis (LVA) is a minimally invasive surgical procedure used to treat lymphedema. Volumetric measurements and quality-of-life assessments are often performed to assess the effectiveness of LVA, but there is no method that provides information regarding postoperative morphological changes in lymphatic vessels and veins after LVA. Photoacoustic lymphangiography (PAL) is an optical imaging technique that visualizes the distribution of light-absorbing molecules, such as hemoglobin or indocyanine green (ICG), and provides three-dimensional images of superficial lymphatic vessels and the venous system simultaneously. In this study, we performed PAL in lymphedema patients before and after LVA and compared the images to evaluate the effect of LVA. @*Methods@#PAL was performed using the PAI-05 system in three patients (one man, two women) with lymphedema, including one primary case and two secondary cases, before LVA. ICG fluorescence lymphography was performed in all cases before PAL. Follow-up PAL was performed between 5 days and 5 months after LVA. @*Results@#PAL enabled the simultaneous visualization of clear lymphatic vessels that could not be accurately seen with ICG fluorescence lymphography and veins. We were also able to observe and analyze morphological changes such as the width and the number of lymphatic vessels and veins during the follow-up PAL after LVA. @*Conclusions@#By comparing preoperative and postoperative PAL images, it was possible to analyze the morphological changes in lymphatic vessels and veins that occurred after LVA. Our study suggests that PAL would be useful when assessing the effect of LVA surgery.
ABSTRACT
Background@#Lymphaticovenular anastomosis (LVA) is a minimally invasive surgical procedure used to treat lymphedema. Volumetric measurements and quality-of-life assessments are often performed to assess the effectiveness of LVA, but there is no method that provides information regarding postoperative morphological changes in lymphatic vessels and veins after LVA. Photoacoustic lymphangiography (PAL) is an optical imaging technique that visualizes the distribution of light-absorbing molecules, such as hemoglobin or indocyanine green (ICG), and provides three-dimensional images of superficial lymphatic vessels and the venous system simultaneously. In this study, we performed PAL in lymphedema patients before and after LVA and compared the images to evaluate the effect of LVA. @*Methods@#PAL was performed using the PAI-05 system in three patients (one man, two women) with lymphedema, including one primary case and two secondary cases, before LVA. ICG fluorescence lymphography was performed in all cases before PAL. Follow-up PAL was performed between 5 days and 5 months after LVA. @*Results@#PAL enabled the simultaneous visualization of clear lymphatic vessels that could not be accurately seen with ICG fluorescence lymphography and veins. We were also able to observe and analyze morphological changes such as the width and the number of lymphatic vessels and veins during the follow-up PAL after LVA. @*Conclusions@#By comparing preoperative and postoperative PAL images, it was possible to analyze the morphological changes in lymphatic vessels and veins that occurred after LVA. Our study suggests that PAL would be useful when assessing the effect of LVA surgery.
ABSTRACT
To practically apply photoacoustic (PA) imaging technology in medicine, we have developed prototypes of a photoacoustic mammography (PAM) device to acquire images for diagnosing breast cancer in the Kyoto University/Canon joint research project (CK project supported by MEXT, Japan). First, the basic ability of the PAM system to visualize the network of blood vessels and the Hb saturation index was evaluated using a prototype of PAM that has a flat scanning detector and is capable of simultaneously acquiring photoacoustic (PA) and ultrasound images. Next, another prototype of a PAM device with hemispherical sensors was developed to improve the visibility of the 3D structure of vessels by reducing the limited view effect. In clinical examination of breast cancer cases, the PAM system allowed 3D visualization of fine vessel networks with a spatial resolution of a half-millimeter and enabled us to determine the features of tumor-related vascular structures in human breast cancer. In addition, the oxygen saturation status of Hb was visualized using two different wavelengths, enabling more precise characterization of the tumor microenvironment. Results of clinical evaluation using our developed prototype of a PAM device confirmed that PA imaging technology has the potential to promote early detection of breast cancer, and realization of its practical use is expected in the near future.