Joint EANM/SNMMI/IHPBA procedure guideline for [99mTc]Tc-mebrofenin hepatobiliary scintigraphy SPECT/CT in the quantitative assessment of the future liver remnant function.

PURPOSE: The aim of this joint EANM/SNMMI/IHPBA procedure guideline is to provide general information and specific recommendations and considerations on the use of [99mTc]Tc-mebrofenin hepatobiliary scintigraphy (HBS) in the quantitative assessment and risk analysis before surgical intervention, selective internal radiation therapy (SIRT) or before and after liver regenerative procedures. Although the gold standard to estimate future liver remnant (FLR) function remains volumetry, the increasing interest in HBS and the continuous request for implementation in major liver centers worldwide, demands standardization. METHODS: This guideline concentrates on the endorsement of a standardized protocol for HBS elaborates on the clinical indications and implications, considerations, clinical appliance, cut-off values, interactions, acquisition, post-processing analysis and interpretation. Referral to the practical guidelines for additional post-processing manual instructions is provided. CONCLUSION: The increasing interest of major liver centers worldwide in HBS requires guidance for implementation. Standardization facilitates applicability of HBS and promotes global implementation. Inclusion of HBS in standard care is not meant as substitute for volumetry, but rather to complement risk evaluation by identifying suspected and unsuspected high-risk patients prone to develop post-hepatectomy liver failure (PHLF) and post-SIRT liver failure.

Laser speckle contrast imaging for intraoperative assessment of liver microcirculation: a clinical pilot study.

BACKGROUND: Liver microcirculation can be affected by a wide variety of causes relevant to liver transplantation and resectional surgery. Intraoperative assessment of the microcirculation could possibly predict postoperative outcome. The present pilot study introduces laser speckle contrast imaging (LSCI) as a new clinical method for assessing liver microcirculation. METHODS: LSCI measurements of liver microcirculation were performed on ten patients undergoing liver resection. Measurements were made during apnea with and without liver blood inflow occlusion. Hepatic blood flow was assessed by subtracting zero inflow signal from the total signal. Zero inflow signal was obtained after hepatic artery and portal vein occlusion. Perfusion was expressed in laser speckle perfusion units, and intraindividual and interindividual variability in liver perfusion was investigated using the coefficient of variability. RESULTS: Hepatic microcirculation measurements were successfully made in all patients resulting in analyzable speckle contrast images. Mean hepatic blood flow was 410±36 laser speckle perfusion units. Zero inflow signal amounted to 40%±4% of the total signal. Intraindividual and interindividual coefficients of variability in liver perfusion were 25% and 28%, respectively. CONCLUSION: Under the conditions of this pilot study, LSCI allows rapid noncontact measurements of hepatic blood perfusion over wide areas. More studies are needed on methods of handling movement artifacts.

Laser speckle contrast imaging for assessment of liver microcirculation.

OBJECTIVE: Laser speckle contrast imaging (LSCI) is a novel technique for microcirculation imaging not previously used in the liver. The aim of the present experimental study was to evaluate the use of LSCI for assessing liver microcirculation. MATERIALS AND METHODS: In six male Wistar rats, the median liver lobe was exposed through a midline laparotomy. Liver blood perfusion was measured simultaneously with LSCI and sidestream dark-field (SDF) imaging at baseline and during sequential temporary occlusions of the portal vein, hepatic artery, and total blood inflow occlusion. Both the inter-individual variability associated with perfusion sampling area and comparisons in perfusion measurements between both imaging techniques were investigated and validated for the application of LSCI in the liver. RESULTS: Occlusion of the hepatic artery, portal vein, and total inflow occlusion resulted in a significant decrease in LSCI signal to 74.7±6.4%, 15.0±2.3%, and 10.4±0.5% respectively (p<0.005 vs. baseline). The LSCI perfusion units correlated with sinusoidal blood flow velocity as measured with SDF imaging (Pearson's r=0.94, p<0.001). In a 10 mm diameter region of interest, as measured with LSCI, baseline inter-individual variability measured by the coefficient of variability was 13%. CONCLUSION: Alterations in LSCI signal during sequential inflow occlusions were in accordance with previously published results on hepatic hemodynamics in the rat and correlated well with our SDF imaging-derived sinusoidal blood flow velocity measurements. We found that LSCI was able to produce reproducible real-time blood perfusion measurements of hepatic microcirculation. Compared to established techniques for liver blood perfusion measurements LSCI holds the advantages of non-contact measurements over large surfaces with a high speed of data acquisition.