Imaging evaluation of potential living donor
Living donor liver transplantation has evolved into a widely accepted therapeutic option to alleviate the persistent shortage of cadaveric liver transplants. This innovative procedure allows healthy adults to donate a portion of their liver to compatible recipients suffering from end-stage liver disease.
This technique, called living-donor liver transplantation (LDLT), provides an effective alternative means of liver transplantation and is a method of expanding the donor pool in light of the demand and supply imbalance for organ transplants. Imaging plays an important role in LDLT programmes by providing robust evaluation of potential donors to ensure that only anatomically suitable donors with no significant co-existing pathology are selected and that crucial information that allows detailed preoperative planning is available.
In the recent past, this preharvest assessment employed a multimodal radiologic evaluation protocol, including:
1. computed tomography (CT) or magnetic resonance imaging (MRI) for liver planimetry and exclusion of parenchymal lesions
2. catheter digital subtraction angiography for the display of the hepatic vascular system
3. endoscopic retrograde cholangiopancreatography (ERCP) for assessing the biliary anatomy
4. liver biopsy for the assessment of hepatic-cellular infiltration.
In an attempt to simplify and shorten such a time consuming and costly procedure to a minimum, both comprehensive “all-in-one” MRI and multidetector computed tomography (MDCT)-protocols have been advocated. Both approaches combine the advantage of minimal invasiveness with the simultaneous assessment of the hepatic parenchymal morphology and a detailed analysis of the biliary and vascular anatomy in a single diagnostic step.
Analysis of the image data is focused on the following aspects:
1. Biliary system (Due to the high incidence of biliary variants, a thorough analysis of the biliary anatomy is essential for the surgical outcome in living donor liver transplantation. Failure to recognize even minor intrahepatic branches crossing the dissection line can result in severe postoperative biliary leakage.)
2. Hepatic arteries
3. Portal & hepatic veins
4. Liver parenchyma & parenchymal lesions (To exclude diffuse liver disease and hepatic masses capable of compromising liver function in the transplant hepatic graft)
5. Transplant volumes (An accurate liver volumetry is of paramount importance to avoid subjecting the donor to unnecessary risks and to reduce the risk of graft failure)
Both “all-in-one” MDCT and “all-in-one” MRI are well suited to extensively assess the liver anatomy of potential donors in a single diagnostic step. This might reduce the need for multimodality evaluation protocols, hence relieving the medical infrastructure, but also augmenting the candidate's acceptance of the pretransplantation survey.
1. Schroeder, Tobias, et al. "“All‐in‐one” imaging protocols for the evaluation of potential living liver donors: Comparison of magnetic resonance imaging and multidetector computed tomography." Liver transplantation 11.7 (2005): 776-787.
2. Low, G., et al. "Imaging evaluation of potential donors in living-donor liver transplantation." Clinical radiology 63.2 (2008): 136-145.