Application of indocyanine green fluorescence imaging in cortical-sparing adrenalectomy: a preliminary study with image quantification techniques
摘要
Previous studies have reported that indocyanine green (ICG) near-infrared fluorescence imaging facilitates laparoscopic adrenalectomy. This study aimed to evaluate the feasibility of ICG imaging in cortical-sparing adrenalectomy and to explore its utility in distinguishing adrenal tumors from normal tissue using quantitative image analysis.
MethodsThis institutional review board-approved, single-center retrospective cohort study included 80 patients who underwent unilateral laparoscopic cortical-sparing adrenalectomy between June 2024 and June 2025. Patients were divided into two groups: the non-ICG group (n = 40), comprising patients operated without ICG between June and December 2024; and the ICG group (n = 40), comprising patients operated with ICG between January and June 2025. Postoperative image analysis was performed using ImageJ software to calculate the adrenal-to-background fluorescence ratio (ABR) and the contrast-to-noise ratio (CNR). Statistical analysis compared CNR values between ICG and conventional views.
ResultsA total of 80 patients underwent unilateral cortical-sparing adrenalectomy. The median operative time was significantly shorter in the ICG group compared to the non-ICG group (63 min vs. 90 min, P < 0.001). In the ICG group, 28 cases (70%) exhibited hyper-fluorescence intensity (ABR > 1), while 12 cases (30%) showed hypo-fluorescence (ABR < 1). On multivariate analysis, tumor size/volume was the only independent predictor of fluorescence intensity (P = 0.019). The CNR values were significantly higher in the ICG view than in the conventional view (P < 0.001), indicating the ICG view has superior contrast for differentiating adrenal tumors from normal tissue.
ConclusionsICG fluorescence imaging effectively enhances intraoperative identification of the adrenal gland and delineates tumor boundaries, potentially reducing operative time. By integrating ICG imaging with quantitative analysis using ImageJ software, visual contrast differences can be objectively measured. This study introduces quantitative metrics, notably CNR, providing a novel and objective method for evaluating the utility of ICG in cortical-sparing surgery.