ICG guided surgery enhances liver tumor detection: a complementary tool for intraoperative ultrasonography – a case series study

Introduction: Indocyanine green (ICG) improves identification of liver tumors. The aim of the study is to determine the effectiveness of ICG fluorescence in detecting liver tumors when used in combination with preoperative MRI and intraoperative ultrasonography (IOUS). Methods: The study included patients who underwent minimally invasive liver resection for malignant tumors. All patients had a preoperative MRI and had ICG administered intravenously (0.2–0.5 mg/kg) 24 h before surgery. In theater, liver parenchyma was scanned with IOUS and ICG fluorescence. Tumors identified were resected and specimens sent for pathology assessment. Results: Sixty-two liver lesions were resected, out of which 42 were previously reported by MRI, 46 were detected by IOUS and 53 were identified by ICG. From 42 tumors detected by MRI, 34 were histologically consistent with cancer. By adding IOUS+ICG, 20 extra lesions were resected and 10 of them were malignant. Accuracy, sensitivity(S) and specificity(E) for malignant tumor detection for MRI, IOUS, and ICG was 70.9% (S 77.2%, E 55%), 74.1% (S 84%, E 50%), and 82.2% (S 97.7%, E 44%). Combination of ICG+IOUS showed the highest results when comparing the ROC curves. Conclusions: ICG is a high-performance adjunct to IOUS, improving intraoperative detection of extra lesions unseen on preoperative imaging.