Imaging evaluation of potential living donor
Introduction
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.
Procedures
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.
Image analysis
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)
Conclusion
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.
Further reading
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.
