Liver tumor boundaries identified intraoperatively using real-time indocyanine green fluorescence imaging

Abstract

Purpose: Clear delineation between tumors and normal tissues is ideal for real-time surgical navigation imaging. We investigated applying indocyanine green (ICG) fluorescence imaging navigation using an intraoperative administration method in liver resection.

Methods: Fifty patients who underwent liver resection were divided into two groups based on clinical situation and operative purpose. In group I, sizes of superficial liver tumors were determined; tiny tumors were identified. In group II, the liver resection margin was determined; real-time navigation was performed. ICG was injected intravenously at the beginning of the operation; the liver surface was observed with a photodynamic eye (PDE).

Results: Liver resection margins were determined using PDE. Fluorescence contrast between normal liver and tumor tissues was obvious in 32 of 35 patients. A boundary for half the liver or specific liver segments was determined in nine patients by examining the portal vein anatomy after ICG injection. Eight small tumors not observed preoperatively were detected; the smallest was 2 mm.

Conclusions: ICG fluorescence imaging navigation is a promising, simple, and safe tool for routine real-time intraoperative imaging during hepatic resection and clinical exploration in hepatocellular carcinoma, enabling high sensibility for identifying liver resection margins and detecting tiny superficial tumors.

Keywords: Fluorescence imaging; Hepatectomy; Indocyanine green; Liver neoplasms.

Fig. 1

Differences in imaging findings between a normal liver and cirrhotic liver with a photodynamic eye after the intraoperative administration of indocyanine green. Normal liver (a); normal liver with uniform fluorescence as seen with a photodynamic eye (b); cirrhotic liver (c); cirrhotic liver with uneven fluorescence as seen with a photodynamic eye (d)

Fig. 2

Changes to the liver after being suppressed by a tumor as seen with a photodynamic eye. A patient with a diaphragmatic tumor exerting downward pressure on the liver with no invasion (a), the liver under pressure as visualized with a photodynamic eye (b)

Fig. 3

Intraoperative indocyanine green administration for visualization of liver metastases with a photodynamic eye. Preoperative computed tomography showing colon cancer with liver metastasis in the right lobe (a), pathologic diagnosis of colon cancer metastasis (b), visible liver tumor during surgery (c), no tumor development visualized with a photodynamic eye, and the boundaries between the tumor and normal liver were clear (d), surgical resection specimens (e), inspection of specimen with a photodynamic eye (f)

Fig. 4

Intraoperative indocyanine green administration for visualization of hepatocellular carcinoma with a photodynamic eye. Preoperative magnetic resonance imaging showing liver cancer in the right lobe (a), pathologic diagnosis of hepatocellular carcinoma (b), tumor viewed intraoperatively (c), no tumor development along with clear tumor boundaries, as visualized with a photodynamic eye (d), after surgery, cutting the specimen revealed that the excised tumor had a complete capsule (e), inspection of a section with a photodynamic eye revealed no tumor development (f), there was visible fluorescence surrounding the normal liver tissue, demonstrating that the tumor tissue cannot quickly absorb indocyanine green, showing intraoperative fluorescence

Fig. 5

Application of a photodynamic eye for identifying tiny tumors with intraoperative indocyanine green administration. Preoperative computed tomography showing a visible VII segment of a liver tumor, and the other segments had no obvious small tumor foci (a), intraoperative photodynamic eye examination of the liver; in addition to known tumors, a 4-mm diameter shadow nodule was visible (b), tumor nodules were found on the liver surface and sent for pathological analysis (c), pathological results confirming hepatocellular carcinoma (d)

Fig. 6

Semi-hepatectomy with the assistance of a photodynamic eye. After ligation of the right hepatic artery and right back branch of the portal vein, the right hepatic ischemia line was not obvious (a); after administering indocyanine green, fluorescence rapidly developed in the left hepatic lobe, and visualization with the photodynamic eye clearly and accurately revealed the hepatectomy line (b). Then, the liver was split along that line; the liver during the splitting process (c). A photodynamic eye can be used at any time to observe the cutting route so it can be adjusted if necessary; resection of one-half of the liver is complete (d); examination of the liver sections with the photodynamic eye, the remaining liver showed full fluorescence, indicating that the resection met the requirements of complete semi-hepatectomy