Hepatectomy risk assessment with functional magnetic resonance imaging

Background
Post hepatectomy liver failure (PHLF) occurs when there is insufficient future liver remnant (FLR) left behind to sustain vital physiological functions following oncological liver surgery. This is associated with significant morbidity and mortality and as such development of a robust measure of FLR function to allow better (PHLF) risk stratification during the preoperative decision making process is of the utmost importance.
Methods
HEPARIM was an observational cohort study to evaluate a new DGE- MRI techniques’ ability to measure regional liver function and predict PHLF risk in patients having major liver resections. Patients underwent pre-operative MRI and Indocyanine Green (ICG) testing and then ICG testing was repeated post-operatively. Primary outcome was correlation between FLR function as measured by regional MRI Gadoxetate clearance (mL/min/kg) and post-operative whole liver function as measured by repeat ICG.
Results
40 patients were recruited over 17 months, mean age was 61 (SD 8.8), 38% of whom were female (n=15) and the commonest pathology was colorectal metastasis (91.3%). Nineteen of these patients successfully underwent major liver resection and were included in final analysis. A positive HEPARIM primary outcome was observed with statistically significant correlation between post-operative ICG and both MRI estimated FLR volumetry (r=0.778) and functional parameters; Normalized FLR-Gadoxetate clearance (r=0.64) and Normalized FLR-
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uptake function (r=0.65). Using multivariant linear regression a more accurate prediction model was obtained (r= 0.871).
Conclusion
This provides further evidence of the accuracy of DGE-MRI in measuring regional FLR function. Future studies should move away from comparisons to other tests such as ICG which have their own shortcomings and focus on actual PHLF prediction which is the outcome of clinical significance. These trials should be conducted in less conservative centers with more experience operating on patients with established chronic liver disease and have a higher PHLF incidence in their practice as a result.