Evaluation to Differentiate between Tumor Lesions and the Parenchyma in Partial Nephrectomies for Renal Tumors Based on Quantitative Fluorescence Imaging Using Indocyanine Green Dye

Abstract

Introduction: Near-infrared fluorescence imaging with indocyanine green is a useful tool during partial nephrectomy. Because an accurate method for judging hasn't been established yet, the success rate may be slightly different and inconsistent.

Materials and methods: A total of 21 cases with suspected renal cancers who had undergone a partial nephrectomy were enrolled. We examined differences in the success rate between malignant lesions and the parenchyma by quantifying fluorescence in the pre-resection and ex vivo phases.

Results: Pre-resection imaging showed a significant degradation of fluorescence in the focused lesion in 76.2% (16/21) of cases. A significant degradation was observed in 73.7% (14/19) of the total malignant lesions, 70.5% (12/17) of cases with a clear cell lesion, 100% (2/2) of cases with non-clear cell lesions, and 100% (2/2) of benign angiomyolipomas. In contrast, imaging of the ex vivo resected specimens showed a significant degradation in fluorescence of the focused lesions in 85.7% (18/21) of cases. A significantly degradation was observed in 84.2% (16/19) of the total malignant lesions, 82.3% (14/17) of cases with a clear cell lesion, 100% (2/2) of cases with non-clear cell lesions, and 100% (2/2) of benign angiomyolipomas.

Conclusion: We firstly evaluated the efficacy of quantitative indocyanine green-based fluorescence as an objective method.

Keywords: Indocyanine green; Infrared fluorescence; Partial nephrectomy.

Copyright © 2019 by S. Karger AG, Basel.

Figures

Fig. 1

Appearance of the HyperEye Medical System. a Overview of the HyperEye Medical System (Mizuho co.); b System for near-infrared fluorescent imaging; c Camera head used for fluorescent imaging.

Fig. 2

Steps for quantifying fluorescence in the pre-operative image. a Appearance under the natural light before resection of the tumor; b Imaging under near-infrared fluorescence: trace of the normal area; c Histogram of the normal parenchyma; d Imaging under near-infrared fluorescence: trace of the tumor area; e Histogram of the tumor area.

Fig. 3

Steps for quantifying the fluorescence in the image of the resected specimens. a Appearance of the resected specimen under natural light; b Imaging under near-infrared fluorescence: trace of the normal area; c Histogram of the normal parenchyma; d Imaging under near-infrared fluorescence: trace of the tumor area; e Histogram of the tumor area.