Reproducibility evaluation of 99mTc-mebrofenin hepatobiliary scintigraphy using SPECT for future remnant liver functional assessment before major hepatectomy

Purpose. - Performances of Tc-99m-mebrofenin hepatobiliary scintigraphy (BIBS) are currently evaluated before major hepatic resection for early detection of liver failure in high risk patients. Published studies included small numbers of patients with planar scintigraphy, and more recently SPECT data. Our aim was to evaluate intra- and interobserver reproducibility of HBS in planar and SPECT modalities for functional assessment of the future remnant liver (FRL) before major hepatic resection. We also evaluated the impact of potential variability factors such as biliary excretion and isocontour threshold choice. Methods. - All the scans were processed twice by three observers. Two regions of interest were drawn around total liver (TL) and FRL, on the planar dataset and with a threshold based algorithm on SPECT after registration with contrast-enhanced CT. Intra- and interobserver reproducibility of the FRL/TL ratio were calculated. When biliary excretion was already visible on SPECT acquisition, it was corrected and the ratio compared before and after correction. The results were also compared between different thresholds of the maximum liver value (-4%, -2%, +2%, +4% of the optimal threshold chosen by the observer). Results. - Thirty patients were included. The intraobserver reproducibility was good (R-2 = 0.847, 0.830 and 0.966) when calculated on planar modality and better with SPECT (R-2 = 0.957, 0.962 and 0.984). There was no significant difference after biliary excretion correction (P = 0.29, P = 0.99 and P = 0.61 for the three observers). The threshold modification caused significant but minor differences (1% on average) for the evaluated thresholds. Conclusions. - The FRL functional evaluation with FIBS including a SPECT acquisition provides a reproducible assessment, hardly affected by potential variability factors, allowing its use in multicentric studies. (C) 2015 Elsevier Masson SAS. All rights reserved.