Combined use of intraoperative ultrasound and indocyanine green fluorescence imaging to detect liver metastases from colorectal cancer

Objectives Surgical excision is the standard strategy for managing liver metastases from colorectal carcinoma. The achievement of negative (R0) margins is a major determinant of disease-free survival in these patients. Current imaging techniques are of limited value in achieving this goal. A new approach to the intraoperative detection of colorectal liver metastatic tissue based on the emission of indocyanine green (ICG) fluorescence was evaluated. Methods A total of 25 consecutive patients with liver metastases from primary colorectal cancers who were eligible for liver resection received a bolus of ICG (0.5 mg/kg body weight) 24 h before surgery. During surgery, ICG fluorescence, which accumulates around lesions as a result of defective biliary clearance, was detected with a near-infrared camera system, the Photodynamic Eye (PDE). Numbers of lesions detected by, respectively, PDE + ICG, intraoperative ultrasound (IOUS) and preoperative computed tomography (CT) were recorded. Results The near-infrared camera plus ICG revealed a total of 77 metastatic liver nodules. Preoperative CT demonstrated 45 (58.4%) and IOUS showed 55 (71.4%). Preoperative CT and IOUS alone were inferior to the combined use of PDE + ICG and IOUS in the detection of lesions of ≤3 mm in size. Conclusions This experience suggests that PDE + ICG, combined with IOUS, may represent a safe and effective tool for ensuring the complete surgical eradication of liver metastases from colorectal cancer.