Fluorescent and Iodized Emulsion for Preoperative Localization of Pulmonary Nodules

Abstract

Objective: This study was conducted to develop a fluorescent iodized emulsion comprising indocyanine green (ICG) solution and lipiodol (ethiodized oil) and evaluate its feasibility for use in a clinical setting. Background: ICG use for the preoperative localization of pulmonary nodules is limited in terms of penetration depth and diffusion. Methods: First, fluorescent microscopy was used to investigate the distribution of ICG-lipiodol emulsions prepared using different methods. The emulsions were injected in 15 lung lobes of 3 rabbits under computed tomography fluoroscopy guidance; evaluation with imaging and radiography was conducted after thoracotomy. Subsequently, the emulsions were used to preoperatively localize 29 pulmonary nodules in 24 human subjects, and wedge resections were performed using fluorescent imaging and C-arm fluoroscopy. Results: The optimal emulsion of 10% ICG and 90% lipiodol mixed through 90 passages had even distribution and the highest signal intensity under fluorescent microscopy; it also had the best consistency in the rabbit lungs, which persisted for 24 hours at the injection site. In human subjects, the mean diameter of pulmonary nodules was 0.9 ± 0.4 cm, and depth from the pleura was 1.2 ± 0.8 cm. All emulsion types injected were well localized around the target nodules without any side effects or procedure-related complications. Wedge resection with minimally invasive approach was successful in all pulmonary nodules with a free resection margin. Conclusions: A fluorescent iodized emulsion prepared by mixing ICG with lipiodol enabled accurate localization and resection of pulmonary nodules.

Targeted Near-Infrared Fluorescence Imaging With Iodized Indocyanine Green in Preoperative Pulmonary Localization: Comparative Efficacy, Safety, Patient Perception With Hook-Wire Localization

“…ICG has also been applied to CT-guided preoperative marking of lung nodules with safe and feasible results (20)(21)(22). Recent research has investigated the optimal ICG solution and lipiodol mixture emulsion with safe and successful out comings (23). To the best of our knowledge, little study has been focusing on the comparison between ICG and conventional hook-wire localization.…”

Localization of Subcentimeter Pulmonary Nodules using an Indocyanine Green Near-infrared Imaging System during Uniportal Video-assisted Thoracoscopic Surgery

“…The Chinese Experts' Consensus of Preoperative-assisted Localization of Pulmonary Nodules (2019 version) recommends localization methods using liquid materials, including ICG, as a 2A-level technique [15]. Rho J et al [16] found that an optimal emulsion of 10% ICG and 90% lipiodol mixed through 90 passages exhibited an even distribution and the highest signal intensity under uorescence microscopy and that all emulsion types injected were well localized around the target nodules without any side effects or procedure-related complications.…”

Fluorescence-guided thoracic surgery

“…ICG has been widely used in surgery for several organs (i.e., hepatic segmentectomies). In the thoracic field, ICG was used for identifying sentinel lymph nodes or tumor localization initially (3)(4)(5). With regard to conditions in the esophagus, ICG is used to prevent the complication of chylothorax during esophagectomy, which is performed to identify the thoracic duct (9).…”

“…In recent years, indocyanine green (ICG) fluorescence has been used to solve the following two problems in thoracic surgery: first, identification of the accurate intersegmental plane in anatomical lung segmentectomy for detecting areas of residual pulmonary blood flow (3)(4)(5) and, second, displaying the location of the tumor or optimal resection line intraoperatively as ICG virtual-assisted lung mapping (ICG-VAL-MAP) (6). Herein, we introduce images and videos that describe the features of surgery using the new ICG technology in the field of minimally invasive thoracic surgery.…”