A comparison of indocyanine green fluorescence and laparoscopic ultrasound for detection of liver tumors.

Background: Indocyanine green (ICG) fluorescence imaging (ICG-FI) has been suggested for intraoperative identification of liver tumors. We aim to compare the intraoperative diagnostic utility of this imaging modality with laparoscopic ultrasound (LUS).

Methods: This is an IRB-approved prospective study. ICG was administered intravenously 1-2 days before surgery. The findings on ICG-FI were compared to those on preoperative cross-sectional imaging (POCSI), LUS, diagnostic laparoscopy (DL).

Results: A total of 144 lesions (62 superficial [visible on DL] and 82 deep) were detected in the study patients. POCSI identified 74%, LUS identified 92%, and ICG-FI identified 43%. ICG-FI detection rate was higher for superficial (95%) versus deep lesions (4%). 3% (4/144) of all lesions were seen only on ICG-FI. However, all of these lesions were small and superficial lesions that were apparent on DL.

Conclusion: Although ICG-FI allowed detection of small superficial lesions that were not identifiable by POCSI or LUS, these lesions were apparent on DL even before ICG-FI. Therefore, its utility as an intraoperative diagnostic modality is limited at the dosage and timing used in the study. We believe that rather than a diagnostic tool, it has more potential for a dynamic use in guiding the resection of superficial lesions and delineating segmental/lobar anatomy.