Intraoperative Fluorescence Visualization in Thoracoscopic Surgery

Novel locally nebulized indocyanine green for simultaneous identification of tumor margin and intersegmental plane

BACKGROUND

Segmentectomy, recommended for early-stage lung cancer or compromised lung function, demands precise tumor detection and intersegmental plane identification. While indocyanine green (ICG) commonly aids in these aspects using near-infrared imaging, its separate administrations through different routes and times can lead to complications and patient anxiety. This study aims to develop a lung-specific delivery method by nebulizing low-dose ICG to targeted lung segments, allowing simultaneous detection of lung tumors and intersegmental planes across diverse animal models.

METHODS

To optimizing the dose of ICG for lung tumor and interlobar fissure detection, different doses of ICG (0.25, 0.1, and 0.05 mg/kg) were nebulized to rabbit lung tumor models. The distribution of locally nebulized ICG in targeted segments was studied to evaluate the feasibility of detecting lung tumor and intersegmental planes in canine lung pseudotumor models.

RESULTS

Near-infrared fluorescence imaging demonstrated clear visualization of lung tumor margin and interlobar fissure using local nebulization of 0.1 mg/kg ICG for only 4 min during surgery in the rabbit models. In the canine model, the local nebulization of 0.05 mg/kg of ICG into the target segment enabled clear visualization of pseudotumor and intersegmental planes for 30 min.

CONCLUSIONS

This innovative approach achieves a reduction in ICG dose and prolonged the visualization time of the intersegmental plane and effectively eliminates the need for the hurried marking of tumors and intersegmental planes. The authors anticipate that lung-specific delivery of ICG will prove valuable for image-guided limited resection of lung tumors in clinical practice.

Efficacy of Near-Infrared Fluorescence Video-Assisted Thoracoscopic Surgery for Small Pulmonary Nodule Resection with Indocyanine Green Inhalation: A Randomized Clinical Trial

BACKGROUND

Small pulmonary nodules (<3 cm) can sometimes be unrecognizable and nonpalpable in video-assisted thoracoscopic surgery (VATS). Near-infrared fluorescence (NIF) VATS after indocyanine green (ICG) inhalation may effectively guide surgeons to locate the nodules.

OBJECTIVE

This study aimed to investigate the safety, feasibility, and efficacy of ICG inhalation-based NIF imaging for guiding small pulmonary nodule resections.

METHODS

Between February and May 2021, the first-stage, non-randomized trial enrolled 21 patients with different nodule depth, ICG inhalation doses, post-inhalation surgery times, and nodule types at a tertiary referral hospital. Between May 2021 and May 2022, the second-stage randomized trial enrolled 56 patients, who were randomly assigned to the fluorescence VATS (FLVATS) or the white-light VATS (WLVATS) group. The ratio of effective guidance and the time consumption for nodule localization were compared.

RESULTS

The first-stage trial proved this new method is safe and feasible, and established a standardized protocol with optimized nodule depth (≤1 cm), ICG dose (0.20-0.25 mg/kg), and surgery window (50-90 min after ICG inhalation). In the second-stage trial, the FLVATS achieved 87.1% helpful nodule localization guidance, which was significantly higher than the WLVATS (59.1%, p < 0.05). The mean nodule locating time (standard deviation) was 1.8 [0.9] and 3.3 [2.3] min, respectively. Surgeons adopting FLVATS were significantly faster (p < 0.01), especially when locating small ground-glass opacities (1.3 [0.6] min vs. 7.0 [3.5] min, p < 0.05). Five of 31 nodules (16.1%) were only detectable by FLVATS, whereas both white light and palpation failed.

CONCLUSIONS

This new method is safe and feasible for small pulmonary nodule resection. It significantly improves nodule localization rates with less time consumption, and hence is highly worthy for clinical promotion. Clinical Trial Registration Chinese Clinical Trial Registry Identifier: ChiCTR2100047326.

Non-invasive molecular imaging for precision diagnosis of metastatic lymph nodes: opportunities from preclinical to clinical applications

Lymph node metastasis is an indicator of the invasiveness and aggressiveness of cancer. It is a vital prognostic factor in clinical staging of the disease and therapeutic decision-making. Patients with positive metastatic lymph nodes are likely to develop recurrent disease, distant metastasis, and succumb to death in the coming few years. Lymph node dissection and histological analysis are needed to detect whether regional lymph nodes have been infiltrated by cancer cells and determine the likely outcome of treatment and the patient's chances of survival. However, these procedures are invasive, and tissue biopsies are prone to sampling error. In recent years, advanced molecular imaging with novel imaging probes has provided new technologies that are contributing to comprehensive management of cancer, including non-invasive investigation of lymphatic drainage from tumors, identifying metastatic lymph nodes, and guiding surgeons to operate efficiently in patients with complex lesions. In this review, first, we outline the current status of different molecular imaging modalities applied for lymph node metastasis management. Second, we summarize the multi-functional imaging probes applied with the different imaging modalities as well as applications of cancer lymph node metastasis from preclinical studies to clinical translations. Third, we describe the limitations that must be considered in the field of molecular imaging for improved detection of lymph node metastasis. Finally, we propose future directions for molecular imaging technology that will allow more personalized treatment plans for patients with lymph node metastasis.