Photoacoustic lymphangiography before and after lymphaticovenular anastomosis

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.

Application of Photoacoustic Imaging for Lymphedema Treatment

“…Compared with these modalities, PAL is useful in LVA, considering its detailed imaging ability to identify lymphatic vessels and to simultaneously depict veins. 25 In preoperative PAL, it is possible to simultaneously visualize the lymphatic vessels and veins to be anastomosed. Moreover, the three-dimensional positional relationship of both lymphatic vessels and veins can be clearly seen, which allowed quick identification of each, leading to efficient LVA.…”

Application of indocyanine green lymphography combined with methylene blue staining in lymphaticovenular anastomosis of lower limb vessels: A prospective study

“…4 Before LVA, the near-infrared fluorescent tracer indocyanine green (ICG) was routinely used to locate the approximate range of lymphatic vessels to be anastomosed. [5][6][7] However, the severe fibrosis of subcutaneous tissues in some patients with lymphedema complicates the separation of the lymphatic vessels for anastomosis from the surrounding fibrotic tissue. Such complex operating conditions require additional measures for precise marking and positioning.…”

Three-dimensional analysis of dermal backflow in cancer-related lymphedema using photoacoustic lymphangiography

“…Photoacoustic imaging has high spatial resolution and the ability to image both endogenous agents (such as oxyhemoglobin, deoxyhemoglobin, and melanin) and exogenous agents (such as ICG). Previous studies [13,[15][16][17] obtained three-dimensional images of superficial lymphatic vessels in healthy participants and lymphedema patients. PAL revealed high spatial resolution images that could identify lymphatic vessels up to 0.2 mm in size.…”