Application of Fluorescent and Iodized Dual Marker for Pre-Operative Localization and Image-Guided Surgery of Pulmonary Nodule

Abstract

Background:This study evaluated the feasibility of pre-operative localization of pulmonary nodule using dual marker composed with indocyanine green (ICG) and lipiodol for minimal and accurate resection in video-assisted thoracoscopic surgery (VATS).Method:To minimize separation of two materials, we mixed with different frequency and ratio of ICG and lipiodol using a 3-way stopcock, and investigated their distribution with fluorescent microscope. Three rabbits were undergone thoracotomy after computed-tomography (CT) fluoroscopy-guidance injection of each 0.1 ml emulsions into different lobes of rabbit lung at 6, 12 or 24 hours. The localized lesions were evaluated by near-infrared optical imaging and radiograph. The 0.3 ml of emulsion was pre-operatively injected into 22 patients under CT fluoroscopy-guidance, and the localization was then evaluated during surgery by near-infrared imaging and mobile C-arm fluoroscopic x-ray. All freshly excised specimens were diagnosed by pathologic examination.Result:In in vitro, the separation time of ICG and lipiodol emulsion was delayed proportionally to mixing frequency and ratio. The emulsion mixed with 90 passages and 90% lipiodol was the least separated at 24 hours. On the rabbit lung, the optimal emulsion remained stably on injection site until 24 hours after injection. Pulmonary nodule localization using the optimal emulsion was performed successfully on the 22 patients without complications.Conclusion:This easy optimal method for pre-operative localization of pulmonary nodule was successfully established. The emulsion can be a useful marker to show the location of lesion to surgeons. However, ICG and lipiodol were not mixed perfectly and evenly. Therefore, there will be needed a future research to stabilize two materials completely.