Recent advances in visualization, imaging, and navigation in hepatobiliary and pancreatic sciences

Circulating tumor cells

Recent progress in molecular oncology enables us to detect the circulating tumor cells (CTCs) in blood with high sensitivity and specificity in gastrointestinal cancers and pancreatic cancers. It can be promising as a useful tool for judging tumor stage, patients' survival, and monitoring response to cancer therapy.

MR imaging for hepatocellular carcinoma

Magnetic resonance imaging is one of the most powerful modalities for hepatocellular carcinoma (HCC) with sufficient sensitivity and specificity, delineates some unique in vivo pathophysiological features of tumors. Chemical shift imaging may depict steatosis of the tumor. Dynamic contrast-enhanced MR imaging is the most powerful tool to assess vascularity of the tumor, which is closely related with malignant transformation under hepatocarcinogenesis. Diffusion-weighted imaging illustrates the cellularity of the tumor. Super-paramagnetic iron oxide accumulating in Kupffer cells, enables detection of hepatocellular-architecture in the lesion. The liver-specific MR contrast agent, gadoxetic acid (Gd-EOB-DTPA) gives potential ability of concurrent assessment of vascularity and hepatocellular-specific properties within the tumor.

Fluorescence imaging using indocyanine green

Indocyanine green (ICG) using fluorescence under infrared light observation provides a new imaging navigation for liver and biliary mapping in hepatectomy and cholecystectomy, omitting biliary intubation, radiation and contrast materials in cholangiography.

Carbon dioxide MDCT cholangiopancreatography

Carbon dioxide enhanced cholangiopancreatography by MDCT virtual reality (CMCP) clearly depicts fourth-order biliary branches and second-order pancreatic ducts without cholangitis and pancreatitis. It enables one to replace the mucin and pancreatic juice and facilitate the detection of cystic lesions of the IPMN. The fusion of CMCP and 3DCT arteriography and venography provides feasible for planning operation and image-guided surgery.

Endoscopic ultrasonography-guided biliary drainage

Endoscopic ultrasonography-guided biliary drainage (EUS-BD) including EUS-guided choledochoduodenostomy (EUS-CDS), EUS-guided hepaticogastrostomy (EUS-HGS) and EUS-guided gallbladder drainage (EUS-GBD), has been developed as an alternative drainage method in obstructive jaundice. The high success rate without fatal adverse event suggests the feasibility and safety of the procedures as far as in high volume endoscopic centers adopting various procedural techniques.

Natural orifice translumenal endoscopic surgery

Natural orifice translumenal endoscopic surgery (NOTES) is a new, evolving concept of minimally invasive surgery that may be useful for the staging of pancreatic and biliary malignancy by peritoneoscopy and lymph node navigation. It is already in clinical use for accurate staging of liver or peritoneal metastasis.

MR-laparoscopy

MRI combined with the laparoscope would be a superior modality to ultrasonography or X-ray CT, because of high soft-tissue contrast, arbitrary slice orientation and no radiation properties for visualizing the cross sectional view of the tissue. The integrated MR-laparoscopy system using transmit/receive RF coil mounted onto the MR-compatible laparoscope helps localize the scope view, scope location and orientation. MR imaging with a respiratory-synchronized navigation seemed to be useful for laparoscopic surgery.

Image overlay navigation surgery by OsiriX

Future directions for visualization will be in the areas of virtual reality.

A new concept of “image overlay surgery” consists of the integration of virtual reality and augmented reality technology. Macintosh and the DICOM viewer OsiriX in OR obtain dynamic 3D images reconstructed to the volume rendering via MDCT.

The registration process was non-invasive and markerless, completed within 5 min. Image overlay navigation was helpful for 3D anatomical understanding of the surgical target in gastrointestinal, hepatobiliary and pancreatic anatomies. The surgeon was able to minimize movement of the gaze, and could utilize the image assistance without interfering with the forceps operation, reducing the gap from virtual reality. Unexpected organ injury could be avoided in all procedures. This provided accurate reconstructions of the tumor and involved lymph node, directly linked with optimization of the surgical procedures. This non-invasive markerless registration using physiological markers on the body surface is useful tool when highlighting hidden structures gives more information and reduces logistical efforts.