Remote assessment and guidance of liver harvesting for transplantation
The harvesting of livers for transplantation involves assessment of the liver's suitability, including an examination of the colour and general appearance of the liver. If the organ is to be split for transplantation into two recipients, the vasculature of the liver must be studied and recorded. Remote assessment of livers and telesurgical guidance could save time and money. This thesis highlights the importance of colour in liver diagnosis, using animal and human models to examine the colour change associated with liver steatosis, which has implications for transplantation. It defines the magnitude and effects of colour distortions produced during remote imaging, and emphasises the need for calibration of any system where the capture and transmission of images is used to assess colour content. It also determines the maximum colour distortion permissible for diagnostic accuracy, with recommendations for viewing conditions, image compression and Internet transmission characteristics. The splitting of livers requires an important decision on where to cut, and it would be useful if a pre-planned incision plane could be viewed in relation to intraoperative landmarks. A system was developed utilizing a three-dimensional index block and multimedia database to allow an intraoperative ultrasound transducer to act as a pointer to pre-operative surgical planning images via image matching, with near real time display of the transducer position. Conclusions drawn include the importance of calibration of remote liver assessment viewing apparatus, and that the use of a multimedia database facilitated image matching so that an ultrasound transducer could be used as an intraoperative positional pointer to surgical planning information. This can be used to facilitate clinical trials of remotely guided liver splitting for multiple transplantations. Further work could include using colour enhancement to improve remote viewing of images, and a clinical trial of the index block system, with the possibility of using multi-modality images.