Michele Diana, MD1, Yu-Yin Liu, MD2, Raoul Pop, MD3, Seong-Ho Kong, MD1, Andras Legner, MD1, Remy Beaujeux, MD, PhD3, Patrick Pessaux, MD, PhD4, Didier Mutter, MD, PhD, FACS4, Bernard Dallemagne, MD5, Jacques Marescaux, MD, FACS, Hon, FRCS, Hon, FJSES, Hon, APSA5. 1IHU-Strasbourg, Institute for Image-Guided Surgery, Strasbourg, France, 2Department of General Surgery, Chang Gung Memorial Hospital, Chang Gung University, Linkou, Taiwan, 3Interventional Radiology Department, University Hospital of Strasbourg, Strasbourg, France, 4Department of General and Digestive Surgery, University Hospital of Strasbourg, Strasbourg, France, 5IRCAD, Research Institute against Cancer of the Digestive System, Strasbourg, France
Intraoperative liver segmentation can be obtained by fluorescence imaging using near-infrared cameras and injecting a fluorophore, e.g. Indocyanine Green (ICG), either systemically (negative staining) after clamping the pedicle of the targeted segment, which will appear non-fluorescent, or by percutaneous injection (positive segment) in the corresponding portal branch. Positive staining provides clearer demarcation lines, but the percutaneous approach is often complex. We aimed to evaluate the feasibility of fluorescence liver segmentation by superselective intra-hepatic artery injection of ICG.
Materials and methods
Eight pigs (mean weight 26.01±5.21kg) were involved. Procedures were performed in a hybrid experimental operative suite equipped with the Artis Zeego® multi-axis robotic angiography system. Four animals served to establish the feasibility of intra-arterial ICG injection for segment demarcation. A pneumoperitoneum was established and 4 ports introduced in the abdominal cavity. Through a femoral artery approach, the celiac trunk was cannulated under angiographic control and a microcatheter was advanced into different segmental hepatic artery branches: sub-segmental (n=1), segmental (n=1), bi-segmental (n=1), tri-segmental (n=1). In each case, 4 escalating doses of ICG were injected (0.001; 0.01; 0.1 and 1 mg/ml) via the arterial catheter. The injected volume was 1ml every 15 minutes. A near-infrared laparoscope (D-Light P; Karl Storz) was used to detect the fluorescent signal. In 3 additional animals, only sub-segments were targeted. A series of metallic markers was placed in the liver parenchyma following the fluorescent demarcation and a 3D CT scan was performed after injecting intra-arterial radiologic contrast, to confirm the correspondence between the fluorescence demarcation and the volume of the liver fed by the artery (Figure 1). In one control animal, simultaneous percutaneous intra-portal angiography and intrarterial angiography were performed to verify the correspondence of the territory served, and escalating doses of ICG were injected in the portal branch.
Bright fluorescence signal enhancing the demarcation of target segments was obtained from 0.1mg/ml, in matter of seconds. Correspondence between the hepatic segments volume and the arterial territories was confirmed by CT angiography after fluorescence-guided laparoscopic marking. Positive staining by intraportal ICG injection was limited by a higher background fluorescence noise, due to the parenchymal accumulation of ICG and porto-systemic shunt.
Fluorescence videography by intrahepatic arterial ICG injection highlights rapidly hepatic segments demarcation and with a better signal-to-background ratio than by portal vein injection. This technique seems promising and should be assessed in the clinical setting.