The beginning of a new era of digestive surgery guided by fluorescence imaging

A Novel Color-Coded Liver Metastasis Mouse Model to Distinguish Tumor and Adjacent Liver Segment

BACKGROUND

It is difficult to distinguish between a tumor and its liver segment with traditional use of indocyanine green (ICG) alone. In the present study, a method was used to limit ICG to the liver segment adjacent to a tumor. A spectrally-distinct fluorescently-labeled tumor-specific antibody against human carcinoembryonic antigen-related cell-adhesion molecules was used to label the metastatic tumor in a patient-derived orthotopic xenograft mouse model to enable color-coded visualization and distinction of a colon-cancer liver metastases and its adjacent liver segment.

MATERIALS AND METHODS

Nude mice received surgical orthotopic implantation in the liver of colon-cancer liver metastases derived from two patients. An anti- carcinoembryonic antigen-related cell-adhesion molecules monoclonal antibody (mAb 6G5j) was conjugated to a near-infrared dye IR700DX (6G5j-IR700DX). After three weeks, mice received 6G5j-IR700DX via tail-vein injection 48 hours before surgery. ICG was intravenously injected after ligation of the left or left lateral Glissonean pedicle resulting in labeling of the segment with preserved blood-flow in the liver. Imaging was performed with the Pearl Trilogy and FLARE Imaging Systems.

RESULTS

The metastatic liver tumor had a clear fluorescence signal due to selective tumor targeting by 6G5j-IR700DX, which was imaged on the 700 nm channel. The adjacent liver segment, with preserved blood-flow in the liver, had a clear fluorescence ICG 800 nm signal, while the left or left lateral segment had no fluorescence signal. Overlay of the images showed clear color-coded differentiation between the tumor fluorescing at 700 nm and the adjacent liver segment fluorescing at 800 nm.

CONCLUSIONS

Color-coding of a liver tumor and uninvolved liver segment has the potential for improved liver resection.

Real-time Navigation for Liver Surgery Using Projection Mapping With Indocyanine Green Fluorescence: Development of the Novel Medical Imaging Projection System

OBJECTIVE

The aim of the present study was to evaluate the usefulness of a new imaging device, the Medical Imaging Projection System (MIPS), which uses the indocyanine green emission signal and active projection mapping, for liver resection.

BACKGROUND

During anatomic liver resection, surgeons cannot completely view the intraparenchymal structure. Although a fluorescent imaging technique using indocyanine green has recently been developed for hepatobiliary surgery, limitations in its application for real-time navigation persist.

METHODS

We conducted a retrospective review of surgical and clinical outcomes for 23 patients who underwent anatomic hepatectomy using the MIPS and 29 patients who underwent the procedure without MIPS guidance, between September 2014 and September 2015.

RESULTS

Preoperative characteristics were comparable between the 2 groups. No significant between-group differences were identified with regard to surgical and clinical outcomes. The demarcation lines were clearly projected by the MIPS in 21 patients; however, the boundary line was undetectable in 2 patients.

CONCLUSIONS

We developed the MIPS to address limitations in current intraoperative imaging methods. Our retrospective analysis provides evidence of the feasibility and clinical utility of the MIPS to identify anatomical landmarks for parenchymal dissection. The MIPS holds promise as a novel real-time navigation system for liver resection.

Current Technical Issues for Surgery of Primary Liver Cancer

Primary liver cancer is the fifth most common cancer worldwide. Apart from liver transplantation, surgical resection has been accepted as the effective local treatment for hepatocellular carcinoma (HCC), one of the most common primary liver cancers. Recent technological innovations including navigation technology and intraoperative real-time fluorescence guidance have been utilized for liver resections in clinical practice. With respect to liver resection techniques, the laparoscopic approach has been increasingly gaining popularity as one of the minimally-invasive treatments of HCC. These technological innovations and technical advancements are expected to further improve the safety and efficacy of liver resections.

Challenges of Clinical Research on Hepatocellular Carcinoma

Challenges of clinical practice and research on hepatocellular carcinoma (HCC) were reviewed. There are several differences in clinical practice between Japan and the Western countries such as tumor markers, understanding of pathological early HCC, imaging diagnosis, treatment strategy, staging system and subclassification of HCC. Further studies are warranted for the clinical practices of Japan to be adopted in the rest of the world.

Advances in research of fluorescence imaging for detection of gastrointestinal tumors

Fluorescence imaging, which has a high sensitivity, produces images by capturing fluorescence signal from the inside of organisms. Over the past few years, notable development of fluorescence imaging technique has been made in the field of gastrointestinal cancer. Imaging instruments and fluorescent probes for fluorescence imaging are being improved and innovated, making it a promising technique for broad clinical applications in the near future. Future clinical applications of fluorescence imaging include aiding diagnosis and surgical treatment of gastrointestinal tumors, which are important development directions of this technique. However, increasing the safety and the accuracy for tumor detection is a challenge for fluorescence imaging. Besides, in order to acquire better diagnostic effects, the combination of fluorescence imaging and other imaging modalities which require novel imaging probes for tumor is also an important trend for fluorescence imaging development.