ICG Use May Aid in Locating Small Tumors for Resection

The use of indocyanine green (ICG) tattooing could help identify small and/or ground glass pulmonary nodules that require resection, according to recent research.

Travis Geraci, MD, of the New York University School of Medicine in New York, N.Y., discussed the findings at the 65^th Annual Meeting & Exhibition of the Southern Thoracic Surgical Association, noting that the study represents the largest prospective series of robotic segmentectomy using electromagnetic navigation bronchoscopy and ICG.

“Small pulmonary nodules are often difficult to localize, particularly when they are deep to the pleura and do not distort the visceral pleura,” Travis Geraci, MD, of the New York University School of Medicine in New York, N.Y., said in a presentation at the 65^th Annual Meeting & Exhibition of the Southern Thoracic Surgical Association. He also said that patients are presenting with smaller pulmonary nodules more frequently, noting that suspicious nodules cannot be percutaneously biopsied, and that patients prefer resection.

Geraci and colleagues use electromagnetic bronchoscopy with near-infrared fluorescence imaging with ICG contrast as their localization technique. They use robotic segmentectomy in all of their pulmonary resection cases for lesions ≤ 9 cm. A robotic approach allows them to localize the nodule. For their study, the authors sought to describe their surgical techniques for ICG use via the bronchoscope as well as the vein to help guide minimally invasive segmentectomy.

Their retrospective review included a consecutive series of patients from one surgeon’s prospective database who were scheduled to undergo an anatomic segmentectomy between January 2010 and February 2018 at two institutions. Study outcomes of interest included segmentectomy and ICG localization. The study authors settled on ICG localization because it is favored for lesions of smaller size (< 1 cm), with ground-glass opacification, and deep to the pleural surface. They considered ICG successful if the target was identified by robotic thoracoscopic NIR fluorescence and if pathology confirmed resection. All other outcomes were considered failures.

Patients received 25 mg of ICG in 10 mL of normal saline, 0.5 mL of which is a peritumoral injection. The rest is intravenously administered after litigation of the segmental pulmonary artery.

According to the study abstract, there were 214 consecutive robotic segmentectomies, and 78 patients received ICG via navigational bronchoscopy or intravenously during the study period. In 75/78 navigational bronchoscopy with ICG cases (96%), the lesion was correctly identified. Median procedure time was 19 minutes.

The researchers noted some improvements in their technique, including: lowering the dose of ICG, the addition of a 1 mL flush, eliminating methylene blue, injection within 4 mm from the pleural surface, and placing a suture in the lesion at the start of the operation prior to ICG diffusion. Median length of stay was one day, and there were no 30- or 90-day fatalities. Five patients experienced morbidity.

According to Geraci, 39% of patients were discharged within 48 hours of robotic segmentectomy. All patients achieved R0 resection. Median nodule size was 1.7 cm, and median number of lymph nodes was 17.

“Navigational bronchoscopy using ICG tattooing is a highly effective technique for identifying small and/or ground glass pulmonary nodules that require resection,” the authors wrote in their abstract. “In addition, intravenous ICG helps delineate the arterial anatomy to guide the staple-line resection of the lung parenchyma during segmentectomy.”