Computer tomography-guided percutaneous Indocyanine Green injection for intraoperative mapping of metastatic suspected lesions

Introduction Surgical treatment in oncology is one of the main part concerning the surveillance rate of the patient in case of tumor recurrence. Metastatic suspected lesions are mostly located in the abdomen or pelvis and are diagnosed by PET, MRI or CT scan. Especially surgery of small lesions in recurrent disease for diagnostic or therapeutic purpose is often challenging. Material and Methods We report a case series of 3 patients who were treated in our department due to a metastatic suspected lesion in PET-CT in follow up. For histological confirmation we performed a laparoscopy using a near infrared camera (NIR) for an improved visualization of the metastatic suspected lesion during surgical treatment. Previously the lesion was marked with an amount of Indocyanine Green (ICG) via computer tomography-guided percutaneous injection. The lesion was identified via NIR camera. While changing the camera in NIR mode, it show up as a blue spot due to the fluorescent signal. After correct identification it was removed and send to pathology. Results In all 3 cases they confirmed the diagnosis of a metastatic lesion. Complication occur in just one case, where the metastatic lymph node infiltrated the external iliac vein, which led to a high blood loss. In this case a vascular interposition had to be done. Conclusion Because of separate wavelengths, which are used for illumination and recording, only the marked area is visible, not the background. Due to correct identification, resection of the lesion was improved and healthy surrounding tissue could have been spared.