Preoperative estimation of remnant hepatic function using fusion images obtained by (99m)Tc-labelled galactosyl-human serum albumin liver scintigraphy and computed tomography

Assessing regional hepatic function changes after hypertrophy induction by radioembolisation: comparison of gadoxetic acid-enhanced MRI and 99mTc-mebrofenin hepatobiliary scintigraphy

BACKGROUND

To compare Gd-ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) and 99mTc-labelled mebrofenin hepatobiliary scintigraphy (HBS) as imaging-based liver function tests after unilateral radioembolisation (RE) in patients with primary or secondary liver malignancies.

METHODS

Twenty-three patients with primary or secondary liver malignancies who underwent Gd-EOB-DTPA-enhanced MRI within a prospective study (REVoluTion) were evaluated. REVoluTion was a prospective open-label, non-randomised, therapy-optimising study of patients undergoing right-sided or sequential RE for contralateral liver hypertrophy at a single centre in Germany. MRI and hepatobiliary scintigraphy were performed before RE (baseline) and 6 weeks after (follow-up). This exploratory subanalysis compared liver enhancement on hepatobiliary phase MRI normalised to the spleen (liver-to-spleen ratio (LSR)) and the muscle (liver-to-muscle ratio (LMR)) with mebrofenin uptake on HBS for the total liver (TL) and separately for the right (RLL) and left liver lobe (LLL).

RESULTS

Mebrofenin uptake at baseline and follow-up each correlated significantly with LSR and LMR on MRI for TL (≤ 0.013) and RLL (≤ 0.049). Regarding the LLL, mebrofenin uptake correlated significantly with LMR (baseline, p = 0.013; follow-up, p = 0.004), whereas with LSR, a borderline significant correlation was only seen at follow-up (p = 0.051; p = 0.046).

CONCLUSION

LSRs and LMR correlate with mebrofenin uptake in HBS. This study indicates that Gd-EOB-DTPA-enhanced MRI and 99mTc-labelled mebrofenin HBS may equally be used to assess an increase in contralateral liver lobe function after right-sided RE.

RELEVANCE STATEMENT

MRI may be a convenient and reliable method for assessing the future liver remnant facilitating treatment planning and monitoring of patients after RE-induced hypertrophy induction.

KEY POINTS

• Both MRI and HBS can assess liver function after RE. • Liver enhancement on MRI correlates with mebrofenin uptake on HBS. • MRI might be a convenient alternative for estimating future liver remnants after hypertrophy induction.

Current status of preoperative risk assessment for posthepatectomy liver failure in patients with hepatocellular carcinoma

Liver resection is an effective therapeutic option for patients with hepatocellular carcinoma. However, posthepatectomy liver failure (PHLF) remains a major cause of hepatectomy-related mortality, and the accurate prediction of PHLF based on preoperative assessment of liver functional reserve is a critical issue. The definition of PHLF proposed by the International Study Group for Liver Surgery has gained acceptance as a standard grading criterion. Liver function can be estimated using a variety of parameters, including routine blood biochemical examinations, clinical scoring systems, dynamic liver function tests, liver stiffness and fibrosis markers, and imaging studies. The Child-Pugh score and model for end-stage liver disease scores are conventionally used for estimating liver decompensation, although the alternatively developed albumin-bilirubin score shows superior performance for predicting hepatic dysfunction. Indocyanine green clearance, a dynamic liver function test mostly used in Japan and other Asian countries, serves as a quantitative estimation of liver function reserve and helps determine indications for surgical procedures according to the estimated risk of PHLF. In an attempt to improve predictive accuracy, specific evaluation of liver fibrosis and portal hypertension has gained popularity, including liver stiffness measurements using ultrasonography or magnetic resonance elastography, as well as noninvasive fibrosis markers. Imaging modalities, including Tc-99m-labeled galactosyl serum albumin scintigraphy and gadolinium-enhanced magnetic resonance imaging, are used for preoperative evaluation in combination with liver volume. This review aims to provide an overview of the usefulness of current options for the preoperative assessment of liver function in predicting PHLF.

Clearance of the liver remnant predicts short-term outcome in patients undergoing resection of hepatocellular carcinoma

BACKGROUND

Estimation of the functional reserve of the remnant liver is important to reduce morbidity and mortality.

AIM

To estimate the functional reserve of the remnant liver in patients with hepatocellular carcinoma (HCC).

METHODS

We reviewed the medical records of 199 patients who underwent resection of HCC. Hepatic clearance of the remnant liver was calculated using fusion images of ^99mTc-labelled galactosyl-human serum albumin liver scintigraphy and computed tomography. Posthepatectomy liver failure (PHLF) was classified according to the International Study Group of Liver Surgery. Complications was classified according to Clavien–Dindo classification. We analyzed by the risk factors for PHLF, morbidity and mortality with multivariate analysis.

RESULTS

Twenty-seven (30%) patients had major complications and 23 (12%) developed PHLF. The incidence of major complications increased with increasing albumin–bilirubin (ALBI) grade. The area under the curve values for hepatic clearance of the remnant liver, liver to heart-plus-liver radioactivity at 15 min (LHL15), and ALBI score predicting PHLF were 0.868, 0.629, and 0.655, respectively. The area under the curve for hepatic clearance of the remnant liver, LHL15, and ALBI score predicting major complications were 0.758, 0.594, and 0.647, respectively. The risk factors for PHLF and major complications were hepatic clearance of the remnant liver and intraoperative bleeding.

CONCLUSION

The measurement of hepatic clearance may predict PHLF and major complications for patients undergoing resection of HCC.

Intensive Multimodal Therapy Combined With Long-term Temozolomide and Etoposide Treatment for Recurrent Osteosarcoma to the Liver and Stomach

The prognosis of patients with osteosarcoma recurring at extrapulmonary/extraosseous sites, especially those with unresectable tumors, is generally dismal due to high resistance to chemotherapy. The present study describes a pediatric patient with osteosarcoma recurring to the liver and stomach. Complete remission was achieved by long-term systemic chemotherapy with temozolomide+etoposide, local irradiation of the stomach, and radical surgical removal of multiple liver metastases following percutaneous transhepatic portal embolization. Second-line multimodal therapy, consisting of salvage chemotherapy and curative local treatment of metastases, may enhance disease-free survival of patients with osteosarcoma experiencing relapse to uncommon sites.

The Impact of Unilateral 90Y-radioembolization on Functional Changes in the Contralateral Hepatic Lobe: The Prospective, Open-label RadioEmbolization, Volumetry, and Liver FuncTion Measurements (REVoluTion) Study

Objectives

To investigate how metabolic function of the contralateral liver lobe is affected by unilateral radioembolization (RE), and to compare the changes in volume and metabolic function.

Background

Unilateral RE induces contralateral liver hypertrophy, but it is unknown if metabolic liver function improves in line with volume increases.

Methods

This prospective open-label, nonrandomized, therapy-optimizing study included all consecutive patients undergoing right-sided or sequential 90Y-RE for liver malignancies without underlying liver disease or biliary obstruction at a single center in Germany. Magnetic resonance imaging volumetry and hepatobiliary scintigraphy were performed immediately before RE and approximately 6 weeks after RE.

Results

Twenty-three patients were evaluated (11 metastatic colorectal cancer, 4 cholangiocellular carcinoma, 3 metastatic breast cancer, 1 each of metastatic neuroendocrine tumor, hepatocellular carcinoma, renal cell carcinoma, oesophageal cancer, pancreatic ductal adenocarcinoma). In the untreated contralateral left liver lobe, mean (SD) metabolic function significantly increased from 1.34 (0.76) %/min/m2 at baseline to 1.56 (0.75) %/min/m2 6 weeks after RE (P = 0.024). The mean (SD) functional volume (liver volume minus tumor volume) of the left liver lobe significantly increased from baseline (407.3 [170.3] mL) to follow-up (499.1 [209.8] mL; P < 0.01), with an equivalent magnitude to the metabolic function increase. There were no reports of grade ≥3 adverse events.

Conclusion

This study indicates that unilobar RE produces a significant increase in the metabolic function, and equivalent volume increase, of the contralateral lobe. RE may be a useful option to induce hypertrophy of the future liver remnant before surgical resection of primary or secondary liver malignancies.

Comparison of nuclear imaging techniques and volumetric imaging for the prediction of postoperative mortality and liver failure in patients undergoing localized liver-directed treatments: a systematic review

Background/aims

Although volumetric imaging by computed tomography (CT) is the gold standard for preoperative assessment of the future liver remnant, nuclear imaging studies have shown promising data. This systematic review summarized the results from trials investigating volumetric and nuclear medicine imaging for the prediction of postoperative mortality and liver failure (LF).

Methods

MEDLINE and Web of Science were searched for papers investigating nuclear imaging methods for the prediction of postoperative clinical outcomes in patients undergoing local, liver-directed treatments. Only papers investigating both preoperative nuclear imaging and CT or magnetic resonance imaging (MR) for the prediction of postoperative mortality and/or LF were included.

Results

Twenty-five trials were qualified for this review. All trials but two used technetium-based tracers for the nuclear imaging examination. Four papers used MR imaging and the remaining used CT for the volumetric evaluation. Overall, the studies were heterogeneous both in terms of methodology and imaging technique. Of the thirteen studies reporting on postoperative mortality, most were descriptive without detailed diagnostic data. A few with detailed data found that nuclear imaging had better predictive value than volumetric imaging. Nineteen studies investigated the prediction of postoperative LF of which seven papers investigated the predictive value of both modalities in multivariable regression analysis. Two papers found that only nuclear imaging parameters were predictive of LF, one paper found that the CT parameter was predictive, and four papers found that combined nuclear and CT/MR imaging parameters were predictive of LF.

Conclusion

Both methodologies were useful in the preoperative assessment of patients scheduled for liver interventions, especially in combination, but nuclear imaging demonstrated better predictive value for postoperative mortality and LF in a few trials. The overall technical and methodological heterogeneity of the included studies complicates the ability to directly compare the clinical utility of the two imaging techniques.

Nuclear imaging methods for the prediction of postoperative morbidity and mortality in patients undergoing localized, liver-directed treatments: a systematic review

Background

Several nuclear imaging methods may predict postoperative liver function and outcome, but none has achieved recommendations in clinical guidelines. The purpose of this systematic review was to summarize the existing knowledge on this topic.

Methods

MEDLINE and Web of Science were searched for studies investigating nuclear medicine imaging methods for the prediction of postoperative liver function in patients undergoing localized, liver-directed treatments. The postoperative endpoints were clinical outcome (morbidity and mortality) as well as measures of postoperative liver function, e.g., liver function assessed by biochemical tests or nuclear imaging.

Results

A total of 1352 references were identified, of which 82 fulfilled the eligibility criteria and were included in the review. Most studies (n = 63) were retrospective studies. The vast majority of studies assessed [^99mTc]Tc-galactosyl serum albumin (GSA) (n = 57) and [^99mTc]Tc-mebrofenin (n = 19). Liver resection was entirely or partly major (involved at least three segments) in 78 reports. There were notable variations in the research methodology, e.g., image acquisition, imaging variables, and endpoints. Thirty-seven studies reported on postoperative mortality, of which most reported descriptive data at the patient level. Of the four reports that performed multivariate analyses, two showed significant predictive results of isotope-based preoperative tests. Fifty-two papers presented data on postoperative liver failure. Multivariate predictive analyses were performed in eighteen trials, of which fifteen showed the significant value of nuclear medicine tests.

Conclusion

There is sparse evidence supporting the significant value of nuclear medicine imaging methods in predicting postoperative mortality. In contrast, a notable number of trials showed a significant prediction of liver failure in multivariate analyses. The research methodology was heterogeneous and exploratory in most trials. Documentation of nuclear medicine tests in this setting awaits the results of properly designed, prospective trials with the standardization of both the nuclear medicine test and endpoints.

The value of 99mTc-labeled galactosyl human serum albumin single-photon emission computerized tomography/computed tomography on regional liver function assessment and posthepatectomy failure prediction in patients with hilar cholangiocarcinoma

BACKGROUND

The aim was to evaluate the value of Tc-labeled galactosyl human serum albumin (Tc-GSA) with single-photon emission computerized tomography (SPECT) in the preoperative assessment of regional liver function and prediction of posthepatectomy liver failure (PHLF) in patients with hilar cholangiocarcinoma (hCCA).

METHODS

Patients with hCCA who underwent Tc-GSA SPECT/computed tomography (CT) before hepatectomy were included. The liver functional parameters of functional liver density (FLD) and predictive residual index (PRI) were calculated based on Tc-GSA SPECT/CT. PHLF was defined according to the International Study Group of Liver Surgery criteria. Univariate and multivariate analyses were used to analyze the risk factors for PHLF. The prediction of PHLF was calculated using receiver operating characteristic curve.

RESULTS

A total of 34 patients were included, 23 of whom underwent preoperative biliary drainage. FLD was significantly higher in patients with drained lobes than that in patients with undrained lobes (0.615 ± 0.190 versus 0.500 ± 0.211, P < 0.05). Sixteen patients suffered PHLF. The ratio of future remnant to total morphological liver volume, future remnant FLD, and PRI differed significantly in patients with and without PHLF according to univariate analysis. PRI was identified as the only independent factor for prediction of PHLF according to multivariate analysis. With a PRI of 0.78, it was possible to predict PHLF with a sensitivity of 83% and a specificity of 93%.

CONCLUSIONS

Tc-GSA SPECT/CT can accurately assess regional liver function and is better able to predict PHLF than conventional methods in patients with hCCA.

Hepatic function assessment to predict post-hepatectomy liver failure: what can we trust? A systematic review

Post hepatectomy liver failure (PHLF) could occur even though an adequate liver volume is preserved. Liver function is not strictly related to the volume and the necessity to pre-operatively predict the future liver remnant (FLR) function is emerging, together with the wide spreading of techniques, aiming to optimize the FLR. The aim of this study was to systematically review all the available tests, to pre-operatively assess the liver function and to estimate the risk of PHLF. A systematic literature research of Medline, Embase, Scopus was performed in accordance to the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines, to identify all the studies available for pre-operative liver function tests to assess the risk of PHLF and/or complications. From the 1122 references retrieved, 79 were included in the review. Dynamic functional tests, such as indocyanine green test (ICG), could evaluate only global liver function, with no definition of functional capacity of the remnant. Magnetic resonance imaging (MRI) with liver-specific contrast agents enables both liver function and volume evaluation; the absence of ionizing radiation showed a better patient's compliance. Nuclear imaging studies as hepatobiliary scintigraphy (HBS) present the unique ability to allow a precise evaluation of the segmental liver function of the remnant liver. Liver volume could overestimate liver function. Several liver function tests are available to evaluate the risk of PHLF in the pre-operative setting. However, no single test alone could accurately predict PHLF. Pre-operative combination between a dynamic quantitative test, such as ICG, with MRI or HBS, should enable a more complete functional evaluation. Functional tests to predict PHLF should be chosen according to patient's characteristics, disease, and center experience.

Validation of Functional Assessment for Liver Resection Considering Venous Occlusive Area after Extended Hepatectomy

BACKGROUND

Previous studies demonstrated that liver function in a veno-occlusive region is approximately 40% of that in a non-veno-occlusive region after hepatectomy with excision of major hepatic vein. We validated the preoperative assessment of future remnant liver (FRL) function based on 40% decreased function of the veno-occlusive region.

METHODS

Sixty patients who underwent hepatectomy with excision of major hepatic vein were analyzed. The FRL functions of the veno-occlusive and non-veno-occlusive regions were calculated with 99mTc-galactosyl human serum albumin scintigraphy single-proton emission computed tomography fusion system and SYNAPSE VINCENT® preoperatively. Risk assessment for hepatectomy was evaluated based on indocyanine green retention at 15 min, and patients with insufficient FRL function were described as marginal.

RESULTS

The median volume and function of the veno-occlusive region per whole liver were 111 ml and 11.0%, respectively. When the function of the veno-occlusive region was presumed as 0%, 40%, and 100%, the FRL function was 62.5%, 68.4%, and 75.0% and 21, 15, and 7 patients were classified as marginal, respectively. When the function of the veno-occlusive region was presumed as 40%, the posthepatectomy liver failure (PHLF) rate of marginal patients was significantly higher than that of safe patients (46.7% vs 8.9%, P = 0.002). Multivariable analysis indicated that marginal FRL function based on 40% decreased function of the veno-occlusive region was the only independent risk factor for PHLF (odds ratio 8.97, P = 0.002) after extended hepatectomy.

CONCLUSION

Assessment of preoperative FRL function based on 40% decreased function of the veno-occlusive region may have high validity.

Evaluation of patients who underwent percutaneous transhepatic portal vein embolisation by Tc-99m GSA scintigraphy

Purpose

To analyse the correlation between the fold change in residual liver volume (RLV) and residual liver uptake at 15 (RLU15) before and after percutaneous transhepatic portal vein embolisation (PTPE).

Material and methods

Between August 2010 and December 2016, 20 patients who underwent PTPE were retrospectively selected. Before and three weeks after PTPE, contrast-enhanced computed tomography (CECT) and Tc-99m GSA scintigraphy were performed to analyse the fold changes in RLV and RLU15, respectively, as well as their correlation.

Results

After PTPE, a significant increase was observed in the RLV (before: 464 ± 99 ml; after: 573 ± 118 ml, p = 0.004) and the RLU15 (before: 11.0 ± 2.9%; after: 17.7 ± 3.8%, p = 5 × 10^-7). The fold increase of RLV and RLU15 in all patients was 1.25 ± 0.15 and 1.66 ± 0.33, respectively. No significant correlation was observed in the fold increase in both RLV and RLU15 (r = 0.14, p = 0.66). In patients no. 3 and 9, who were outliers, the increase in RLV was minimal and RLU15 increased greatly, and these 2 patients underwent radical hepatectomy after PTPE.

Conclusions

No correlation was observed between the fold increase in RLV and RLU15 before and after PTPE. In order to accurately evaluate the residual liver function, it should be considered necessary to evaluate not only by morphological CECT volumetry, but also by functional outcome of Tc-99m GSA scintigraphy.

Residual liver volume may not necessarily reflect RLF. It may be possible to improve the radical resection rate by detecting the potential increase of RLF with RLU15 of Tc-99m GSA scintigraphy.

99mTc-GSA SPECT/CT fusion imaging for hepatectomy candidates with extremely deteriorated ICG value

PURPOSE

The value of indocyanine green (ICG) test is negatively affected in patients with intrahepatic shunt, ICG excretory defect, or jaundice. This study evaluated ^99mTc-GSA SPECT/CT fusion imaging for assessing liver function in patients with severely deteriorated ICG values.

MATERIALS AND METHODS

Thirteen hepatectomy candidates with ICG retention rates over 40% were retrospectively analyzed. The ICG clearance rate (KICG) and estimated KICG obtained by ^99mTc-GSA scintigraphy (KGSA) were used to evaluate preoperative whole liver function. Remnant liver function was assessed using the remnant (rem) KICG (= KICG × volumetric rate) and remKGSA (= KGSA × functional rate) indices; hepatectomy was considered unsafe for values < 0.05. The correlations of remKICG and remKGSA with postoperative mortality and morbidity were also investigated.

RESULTS

KGSA values were significantly greater than KICG values (median: 0.12 vs. 0.059; p < 0.01); remKGSA values were greater than remKICG values in all patients (median: 0.107 vs. 0.0413; p < 0.01). Hepatectomy was considered unsafe in 70% patients using remKICG, and in none of those using remKGSA; liver failure or postoperative mortality did not occur.

CONCLUSIONS

^99mTc-GSA SPECT/CT fusion imaging enables more accurate liver function assessment than the ICG test in patients with severely deteriorated ICG values.

Impaired Value of 99m Tc-GSA Scintigraphy as an Independent Risk Factor for Posthepatectomy Liver Failure in Patients with Hepatocellular Carcinoma

BACKGROUND

Posthepatectomy liver failure (PHLF) was recently defined with the corresponding recommendations as follows: grade A, no change in clinical management; grade B, clinical management with noninvasive treatment; and grade C, clinical management with invasive treatment. In this study, we identified the risk factors for grade B and C PHLF in patients with hepatocellular carcinoma (HCC).

METHODS

Of 339 HCC patients who underwent curative hepatic resection, 218 were included for analysis. The LHL15 index (uptake ratio of the liver to that of the liver and heart at 15 min) was measured by 99m Tc-GSA (99m technetium-labelled galactosyl human serum albumin); remnant LHL15 was calculated as LHL15 × [1 - (resected liver weight - tumor volume)/whole liver volume without tumor].

RESULTS

A total of 163 patients were classified as having no PHLF, whereas 17, 37, and 1 patient had PHLF grade A, B, and C, respectively. There were significant differences in indocyanine green R15, serum albumin, prothrombin time, Child-Pugh classification, LHL15 and remnant LHL15 between patients with grades B/C PHLF and patients with grade A or no PHLF. Only remnant LHL15 was identified as an independent risk factor for grades B/C PHLF (p = 0.023), with a cut-off value of 0.755.

CONCLUSIONS

Remnant LHL15 was an independent risk factor for grades B/C PHLF. Patients with impaired remnant LHL15 value of <0.755 should be carefully monitored for PHLF.

Synthesis and biological evaluation of novel mono- and bivalent ASGP-R-targeted drug-conjugates

Asialoglycoprotein receptor (ASGP-R) is a promising biological target for drug delivery into hepatoma cells. Nevertheless, there are only few examples of small-molecule conjugates of ASGP-R selective ligand equipped by a therapeutic agent for the treatment of hepatocellular carcinoma (HCC). In the present work, we describe a convenient and versatile synthetic approach to novel mono- and multivalent drug-conjugates containing N-acetyl-2-deoxy-2-aminogalactopyranose and anticancer drug - paclitaxel (PTX). Several molecules have demonstrated high affinity towards ASGP-R and good stability under physiological conditions, significant in vitro anticancer activity comparable to PTX, as well as good internalization via ASGP-R-mediated endocytosis. Therefore, the conjugates with the highest potency can be regarded as a promising therapeutic option against HCC.

ICG Clearance Test and 99mTc-GSA SPECT/CT Fusion Images

Preoperative estimation of future remnant liver function is critical for major hepatic surgery to avoid postoperative morbidity and mortality. Among several liver function tests, the indocyanine green (ICG) clearance test is still the most popular dynamic method. The usefulness of ICG clearance test parameters, such as ICGR15, KICG, or PDRICG, has been reported by many investigators. The transcutaneous non-invasive pulse dye densitometry system has made the ICG clearance test more convenient and attractive, even in Western countries. The concept of future remnant KICG (rem KICG), which combines the functional aspect and the volumetric factor of the future remnant liver, seems ideal for determining the maximum extent of major hepatic resection that will not cause postoperative liver failure. For damaged livers with functional heterogeneity among the hepatic segments, fusion images combining technetium-99m-diethylenetriaminepentaacetic acid-galactosyl human serum albumin single photon emission computed tomography (99mTc-GSA SPECT) and X-ray CT are helpful to precisely estimate the functional reserve of the future remnant liver. Another technique for image-based liver function estimation, gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid(Gd-EOB)-enhanced magnetic resonance imaging, may be an ideal candidate for the preoperative determination of future remnant liver function. Using these methods effectively, morbidity and mortality after major hepatic resection could be reduced.

Significance of functional hepatic resection rate calculated using 3D CT/(99m)Tc-galactosyl human serum albumin single-photon emission computed tomography fusion imaging

AIM

To evaluate the usefulness of the functional hepatic resection rate (FHRR) calculated using 3D computed tomography (CT)/(99m)Tc-galactosyl-human serum albumin (GSA) single-photon emission computed tomography (SPECT) fusion imaging for surgical decision making.

METHODS

We enrolled 57 patients who underwent bi- or trisectionectomy at our institution between October 2013 and March 2015. Of these, 26 patients presented with hepatocellular carcinoma, 12 with hilar cholangiocarcinoma, six with intrahepatic cholangiocarcinoma, four with liver metastasis, and nine with other diseases. All patients preoperatively underwent three-phase dynamic multidetector CT and (99m)Tc-GSA scintigraphy. We compared the parenchymal hepatic resection rate (PHRR) with the FHRR, which was defined as the resection volume counts per total liver volume counts on 3D CT/(99m)Tc-GSA SPECT fusion images.

RESULTS

In total, 50 patients underwent bisectionectomy and seven underwent trisectionectomy. Biliary reconstruction was performed in 15 patients, including hepatopancreatoduodenectomy in two. FHRR and PHRR were 38.6 ± 19.9 and 44.5 ± 16.0, respectively; FHRR was strongly correlated with PHRR. The regression coefficient for FHRR on PHRR was 1.16 (P < 0.0001). The ratio of FHRR to PHRR for patients with preoperative therapies (transcatheter arterial chemoembolization, radiation, radiofrequency ablation, etc.), large tumors with a volume of > 1000 mL, and/or macroscopic vascular invasion was significantly smaller than that for patients without these factors (0.73 ± 0.19 vs 0.82 ± 0.18, P < 0.05). Postoperative hyperbilirubinemia was observed in six patients. Major morbidities (Clavien-Dindo grade ≥ 3) occurred in 17 patients (29.8%). There was no case of surgery-related death.

CONCLUSION

Our results suggest that FHRR is an important deciding factor for major hepatectomy, because FHRR and PHRR may be discrepant owing to insufficient hepatic inflow and congestion in patients with preoperative therapies, macroscopic vascular invasion, and/or a tumor volume of > 1000 mL.

Liver function assessment using 99mTc-GSA single-photon emission computed tomography (SPECT)/CT fusion imaging in hilar bile duct cancer: A retrospective study

BACKGROUND

The objective of this study was to determine the utility of Tc-99m-diethylenetriamine-penta-acetic acid-galactosyl human serum albumin ((99m)Tc-GSA) single-photon emission computed tomography (SPECT)/CT fusion imaging for posthepatectomy remnant liver function assessment in hilar bile duct cancer patients.

METHODS

Thirty hilar bile duct cancer patients who underwent major hepatectomy with extrahepatic bile duct resection were retrospectively analyzed. Indocyanine green plasma clearance rate (KICG) value and estimated KICG by (99m)Tc-GSA scintigraphy (KGSA) and volumetric and functional rates of future remnant liver by (99m)Tc-GSA SPECT/CT fusion imaging were used to evaluate preoperative whole liver function and posthepatectomy remnant liver function, respectively. Remnant (rem) KICG (= KICG × volumetric rate) and remKGSA (= KGSA × functional rate) were used to predict future remnant liver function; major hepatectomy was considered unsafe for values <0.05. The correlation of remKICG and remKGSA with posthepatectomy mortality and morbidity was determined.

RESULTS

Although remKICG and remKGSA were not significantly different (median value: 0.071 vs 0.075), functional rates of future remnant liver were significantly higher than volumetric rates (median: 0.54 vs 0.46; P < .001). Hepatectomy was considered unsafe in 17% and 0% of patients using remKICG and remKGSA, respectively. Postoperative liver failure and mortality did not occur in the patients for whom hepatectomy was considered unsafe based on remKICG. remKGSA showed a stronger correlation with postoperative prothrombin time activity than remKICG.

CONCLUSION

(99m)Tc-GSA SPECT/CT fusion imaging enables accurate assessment of future remnant liver function and suitability for hepatectomy in hilar bile duct cancer patients.

Stepwise approach to curative surgery using percutaneous transhepatic cholangiodrainage and portal vein embolization for severe bile duct injury during laparoscopic cholecystectomy: a case report

Laparoscopic cholecystectomy (LC) has been recently adapted to acute cholecystitis. Major bile duct injury during LC, especially Strasberg-Bismuth classification type E, can be a critical problem sometimes requiring hepatectomy. Safety and definitive treatment without further morbidities, such as posthepatectomy liver failure, is required. Here, we report a case of severe bile duct injury treated with a stepwise approach using ^99mTc-galactosyl human serum albumin (^99mTc-GSA) single-photon emission computed tomography (SPECT)/CT fusion imaging to accurately estimate liver function.

A 52-year-old woman diagnosed with acute cholecystitis underwent LC at another hospital and was transferred to our university hospital for persistent bile leakage on postoperative day 20. She had no jaundice or infection, although an intraperitoneal drainage tube discharged approximately 500 ml of bile per day. Recorded operation procedure showed removal of the gallbladder with a part of the common bile duct due to its misidentification, and each of the hepatic ducts and right hepatic artery was injured. Abdominal enhanced CT revealed obstructive jaundice of the left liver and arterial shunt through the hilar plate to the right liver. Magnetic resonance cholangiopancreatography revealed type E4 or more advanced bile duct injury according to the Bismuth-Strasberg classification. We planned a stepwise approach using percutaneous transhepatic cholangiodrainage (PTCD) and portal vein embolization (PVE) for secure right hemihepatectomy and biliary-jejunum reconstruction and employed ^99mTc-GSA SPECT/CT fusion imaging to estimate future remnant liver function. The left liver function rate had changed from 26.2 % on admission to 26.3 % after PTCD and 54.5 % after PVE, while the left liver volume rate was 33.8, 33.3, and 49.6 %, respectively. The increase of liver function was higher than that of volume (28.3 vs. 15.8 %). On postoperative day 63, the curative operation, right hemihepatectomy and biliary-jejunum reconstruction, was performed, and posthepatectomy liver failure could be avoided.

Careful consideration of treatment strategy for each case is necessary for severe bile duct injury with arterial injury requiring hepatectomy. The stepwise approach using PTCD and PVE could enable hemihepatectomy, and ^99mTc-GSA SPECT/CT fusion imaging was useful to estimate heterogeneous liver function.

Preliminary study on liver function changes after trisectionectomy with versus without prior portal vein embolization

PURPOSE

Post-hepatectomy liver failure (PHLF) is the major risk factor for mortality after hepatectomy. Preoperative planning of the future liver remnant volume reduces PHLF rates; however, future liver remnant function (FLR-F) might have an even stronger predictive value. In this preliminary study, we used a new method to calculate FLR-F by the LiMAx test and computer tomography-assisted volumetric-analysis to visualize liver function changes after portal vein embolization (PVE) before extended hepatectomy.

METHODS

The subjects included patients undergoing extended right hepatectomy either directly (NO-PVE group) or after PVE (PVE group). Computed tomography (CT) scan and liver function tests (LiMAx) were done before PVE and preoperatively. FLR-F was calculated and correlated with the postoperative liver function.

RESULTS

There were 12 patients in the NO-PVE group and 19 patients in the PVE group. FLR-F and postoperative liver function correlated significantly in both groups (p = 0.036, p = 0.011), although postoperative liver function was slightly overestimated, at 32 and 45 µg/kg/min, in the NO-PVE and PVE groups, respectively. LiMAx value did not change after PVE.

CONCLUSIONS

Volume-function analysis using LiMAx and CT scan enables us to reliably predict early postoperative liver function. Global enzymatic liver function measured by the LiMAx test did not change after PVE, confirming that liver function distribution in the liver stays constant after PVE. An overestimation of FLR-F is needed to compensate for the intraoperative liver injury that occurs in patients undergoing extended hepatectomy.

Improved liver function after portal vein embolization and an elective right hepatectomy

BACKGROUND

Portal vein embolization (PVE) is used before extensive hepatic resections to increase the volume of the future remnant liver within acceptable safety margins (conventionally >0.6% of the patient's weight). The objective was to determine whether pre-operative PVE impacts on post-operative liver function independently from the increase in liver volume.

METHODS

The post-operative liver function of patients who underwent an anatomical right liver resection with (n = 28) and without (n = 53) PVE were retrospectively analysed. Donors of the right liver were also analysed (LD) (n = 17).

RESULTS

Patient characteristics were similar, except for age, weight and American Society of Anesthesiologists (ASA) score that were lower in LD. Post-operative factor V and bilirubin levels were, respectively, higher and lower in patients with PVE compared with patients without PVE or LD (P < 0.05). Patients with PVE had an increased blood loss, blood transfusions and sinusoidal obstruction syndrome. The day-3 bilirubin level was 40% lower in the PVE group compared with the no-PVE group after adjustment for body weight, chemotherapy, operating time, Pringle time, blood transfusions, remnant liver volume, pre-operative bilirubin level and pre-operative prothrombin ratio (P = 0.001).

CONCLUSIONS

For equivalent volumes, the immediate post-operative hepatic function appears to be better in livers prepared with PVE than in unprepared livers. Future studies should analyse whether the conventional inferior volume limit that allows a safe liver resection may be lowered when a PVE is performed.

(99m)Tc-GSA SPECT/CT fused images for assessment of hepatic function and hepatectomy planning

To assure safe hepatectomy, accurate estimation of the functional reserve of the future remnant liver is crucial. The combination of indocyanine green retention rate at 15 min and CT volumetry is widely used in deciding on the extent of hepatectomy. On the other hand, there are quantitative indices calculated from (99m)Tc-GSA scintigraphy that reflect the number and function of hepatocytes. Therefore, there are many indices calculated from (99m)Tc-GSA scintigraphy that have been reported. In recent Annals of Surgical Oncology on Oct. 2014 the Uptake Index (UI) calculated from (99m)Tc-GSA scintigraphy was reported to be useful for hepatectomy planning and postoperative liver failure prediction. In this paper, we report on the usefulness and limits of quantitative indices calculated from (99m)Tc-GSA SPECT/CT for preoperative simulation.

Preoperative estimation of future remnant liver function following portal vein embolization using relative enhancement on gadoxetic acid disodium-enhanced magnetic resonance imaging

Objective

To retrospectively evaluate relative enhancement (RE) in the hepatobiliary phase of gadoxetic acid disodium-enhanced magnetic resonance (MR) imaging as a preoperative estimation of future remnant liver (FRL) function in a patients who underwent portal vein embolization (PVE).

Materials and Methods

In 53 patients, the correlation between the indocyanine green clearance (ICG-K) and RE imaging was analyzed before hepatectomy (first analysis). Twenty-three of the 53 patients underwent PVE followed by a repeat RE imaging and ICG test before an extended hepatectomy and their results were further analyzed (second analysis). Whole liver function and FRL function were calculated on the MR imaging as follows: RE x total liver volume (RE Index) and FRL-RE x FRL volume (Rem RE Index), respectively. Regarding clinical outcome, posthepatectomy liver failure (PHLF) was evaluated in patients undergoing PVE.

Results

Indocyanine green clearance correlated with the RE Index (r = 0.365, p = 0.007), and ICG-K of FRL (ICG-Krem) strongly correlated with the Rem RE Index (r = 0.738, p < 0.001) in the first analysis. Both the ICG-Krem and the Rem RE Index were significantly correlated after PVE (r = 0.508, p = 0.013) at the second analysis. The rate of improvement of the Rem RE Index from before PVE to after PVE was significantly higher than that of ICG-Krem (p = 0.014). Patients with PHLF had a significantly lower Rem RE Index than patients without PHLF (p = 0.023).

Conclusion

Relative enhancement imaging can be used to estimate FRL function after PVE.

Alterations in hepatic lobar function in regenerating rat liver

BACKGROUND

Ligation of a branch of the portal vein redirects portal blood to nonligated lobes resulting in lobar hypertrophy. Although the effect of portal vein ligation on liver volume is well documented, the parallel alterations in liver function are still the subject of controversy. Our aim was to assess the time-dependent reactions of regional hepatic function to portal vein ligation by selective biliary drainage.

METHODS

Male Wistar rats (n = 44) underwent 80% portal vein ligation. Before the operation as well as 1, 2, 3, 5, and 7 d after circulation, morphology and function (laboratory blood test; hepatic bile flow; plasma disappearance rate of indocyanine green; and biliary indocyanine green excretion) of the liver were examined.

RESULTS

Although portal vein ligation affected liver circulation and morphology to a great extent, serum albumin levels, bilirubin levels, and total hepatic bile flow did not change significantly after the operation. Nevertheless, plasma disappearance rate and biliary indocyanine green excretion indicated a temporary impairment of total liver function with the lowest value on the second day and normalization by the fifth day. Bile production and biliary indocyanine green excretion of ligated lobes decreased rapidly after the operation and remained persistently suppressed, whereas the secretory function of nonligated lobes--after a temporary decline--showed a greater increase than the weight of the lobes.

CONCLUSIONS

Portal vein ligation induced temporary impairment of total liver function, followed by rapid recovery mainly by reason of increase in the function of nonligated lobes. Functional increase in nonligated lobes was more pronounced than suggested by the degree of volume gain.

Triggered liver regeneration: from experimental model to clinical implications

BACKGROUND

Major liver resection is the only therapeutic option for patients with malignant liver tumors. However, extended hepatectomy often leads to postoperative liver failure, mainly due to insufficient amounts of the remnant liver. Recently, selective portal vein occlusion (PVO) has been introduced to increase the remnant liver volume. This novel surgical technique initiated a progressive development in liver surgery, resulting in a significant increment in potential candidates for curative liver resection.

SUMMARY

The theoretical basis for this great advancement is formed by an understanding of the mechanisms of PVO-induced liver regeneration, mainly obtained from animal studies. The aim of this review is to give a comprehensive overview of the relevant animal models of PVO and to discuss the main characteristics of triggered liver regeneration, including the induced hemodynamic, morphological and functional alterations as well as the underlying molecular mechanisms, which might be of interest in both the laboratory and the clinic. Key Messages: Although basic research revealed the main characteristics of PVO-triggered liver regeneration within the last decades, several important issues regarding the regenerative process remain uncertain. To answer these open questions, additional well-designed animal experiments are needed in the future, which allow further refinement of this surgical technique.

Quantitative index calculated by (99m)Tc-GSA scintigraphy

(99m)Tc-galactosyl human serum albumin (GSA) scintigraphy is useful to evaluate hepatic function and hepatic functional reserve. A reliable SPECT and CT integrated system is now commercially available. Using this system, we can obtain (99m)Tc-GSA SPECT/CT fused imaging with a small registration error. Therefore, the (99m)Tc-GSA scintigraphy techniques prove more useful in clinical practice than have been previously reported. In the latest Annals of Surgical Oncology on Oct 2014, the uptake index (UI) values calculated from (99m)Tc-GSA scintigraphy are reported to be useful for predicting the functional reserve of the future remnant liver. In this paper, we describe the usefulness of (99m)Tc-GSA scintigraphy as well as some cautions that are necessary as regards using the system.

Liver resection for HCC: patient's selection and controversial scenarios

Liver resection is a valuable curative option for patients with hepatocellular carcinoma (HCC). Yet, the balance between the operative risk following hepatectomy for HCC occurring on chronic liver disease and the oncologic prognosis of advanced lesions have led treatment recommendations to limiting the place of liver resection to selected patients with preserved liver function harbouring early-stage tumours. However, better understanding of the natural history of both tumour and underlying liver disease, sophisticated assessment of the liver function, improvements in the preoperative management of the patients with the use of liver volume modulation, refinements in surgical technique including anatomic resection and laparoscopic approach along with tailored management of recurrences have led expert centres to better define and extend the indications for liver resection. In this setting, the reported favourable operative results and long-term outcomes following resection of HCC in a number of controversial scenarios support that current guidelines could be refined.

Assessment of hepatic functional regeneration after hepatectomy using (99m)Tc-GSA SPECT/CT fused imaging

BACKGROUND

The liver itself regenerates after hepatectomy but little is known about how much hepatic function recovers during the regeneration. The liver uptake value (LUV), calculated from Tc-99m-labeled galactosyl-human-serum-albumin ((99m)Tc-GSA) SPECT/CT fused images, is reliable and useful for evaluating hepatic function. In this study, we evaluated the clinical usefulness of LUV for estimating hepatic functional regeneration after hepatectomy.

METHODS

We enrolled 95 patients who had undergone (99m)Tc-GSA SPECT/CT tests before/on days 30 and 90 after hepatectomy. We determined the LUV from the (99m)Tc-GSA SPECT/CT images and calculated the %LUV (postoperative LUV/preoperative LUV × 100). Based on surgical procedures and histopathological damage, we divided the study population into patients with severe (n = 12) or non-severe fibrosis (n = 33) who had undergone minor hepatectomy, and patients with severe (n = 14) or non-severe fibrosis (n = 36) having major hepatectomy. On the 90th post-hepatectomy day, five patients manifested liver failure; in these patients, we analyzed the co-relation between liver failure and the results of the liver function tests performed on day 30 after surgery.

RESULTS

Although the %LUV reached 95.4 ± 12.2 % in 30 days, in patients with severe fibrosis after major hepatectomy it remained below 90 %. Patients having low %LUV (<75 %) and high serum bilirubin (>2.0 mg/dl) at 30 days showed a relative risk of liver failure of 12.0 and 4.5 (p < 0.001 and p < 0.001), respectively.

CONCLUSIONS

Although the %LUV recovered to about 95 % in all patients within 30 days after the hepatectomy, in patients with severe fibrosis having major hepatectomy, the process of recovery was delayed. The %LUV corresponded to the quality of the liver function which emerged in a later post-hepatectomy phase.

Functional discrepancy between two liver lobes after hemilobe biliary drainage in patients with jaundice and bile duct cancer: an appraisal using (99m)Tc-GSA SPECT/CT fusion imaging

PURPOSE

To determine the functional discrepancy between the two liver lobes using technetium 99m ((99m)Tc) diethylenetriamine-pentaacetic acid-galactosyl human serum albumin ( GSA diethylenetriamine-pentaacetic acid-galactosyl human serum albumin ) single photon emission computed tomography (SPECT)/computed tomography (CT) fusion imaging following preoperative biliary drainage and portal vein embolization ( PVE portal vein embolization ) in patients with jaundice who have bile duct cancer ( BDC bile duct cancer ).

MATERIALS AND METHODS

This retrospective study was approved by the institutional review board, with waiver of informed consent. Preoperative (99m)Tc- GSA diethylenetriamine-pentaacetic acid-galactosyl human serum albumin SPECT/CT fusion images from 32 patients with extrahepatic BDC bile duct cancer were retrospectively reviewed. Patients were classified into four groups according to the extent of biliary drainage and presence of a preoperative right PVE portal vein embolization : right lobe drainage group (right drainage), bilateral lobe drainage group (bilateral drainage), left lobe drainage group (left drainage), and left lobe drainage with right PVE portal vein embolization group (left drainage with right PVE portal vein embolization ). Percentage volume and percentage function were measured in each lobe using fusion imaging. The ratio between percentage function and percentage volume (the function-to-volume ratio) was calculated for each lobe, and the results were compared among the four groups. Statistical analysis was performed with Wilcoxon signed-rank tests and Mann-Whitney U tests.

RESULTS

The median values for the function-to-volume ratio in the right drainage, bilateral drainage, left drainage, and left drainage with right PVE portal vein embolization group were 1.12, 1.05, 1.02, and 0.81 in the right lobe; and 0.51, 0.88, 0.96, and 1.17 in the left lobe. Significant differences in the function-to-volume ratio were observed among the four groups (right drainage vs bilateral drainage vs left drainage vs left drainage with right PVE portal vein embolization ; with P < .002, P = .023, and P < .002 for the right lobe and P < .001, P = .023, and P < .002 for the left lobe).

CONCLUSION

Hepatic lobar function significantly differs between the two lobes, depending on the extent of biliary drainage and the presence of portal vein embolization.

The role of organic anion transporters in diagnosing liver diseases by magnetic resonance imaging

The expression and transport functions of organic anion transporters are modified in liver diseases, and therefore the vascular clearances of endogenous and exogenous organic anions that are taken up by these transporters have been used to assess liver diseases in patients. More recently, liver imaging with hepatobiliary contrast agents, tracers, and dyes that cross hepatocytes through the organic anion transporting polypeptides (OATPs)-multidrug resistance-associated proteins (MRPs) pathway were developed to detect and characterize focal lesions and to assess the severity of diffuse liver diseases. This review focuses mainly on magnetic resonance imaging and highlights the growing interest in imaging the OATPs-MRP2 pathway to better understand liver diseases. Imaging provides noninvasive measurements of tissue concentrations that result from the interplay between influx and efflux membrane transport systems in normal or injured hepatocytes. Imaging with magnetic resonance hepatobiliary contrast agents improves the detection and the characterization of hepatic focal lesions. New developments of imaging to assess liver function and understand the hepatocellular concentrations of contrast agents are discussed.

CT/99mTc-GSA SPECT fusion images demonstrate functional differences between the liver lobes

AIM: To evaluate the functional differences between the 2 liver lobes in non-cirrhotic patients by using computed tomography/^99mTc-galactosyl human serum albumin (CT/^99mTc-GSA) single-photon emission computed tomography (SPECT) fusion images.

METHODS: Between December 2008 and March 2012, 264 non-cirrhotic patients underwent preoperative liver function assessment using CT/^99mTc-GSA SPECT fusion images. Of these, 30 patients, in whom the influence of a tumor on the liver parenchyma was estimated to be negligible, were selected. Specifically, the selected patients were required to meet either of the following criteria: (1) the presence of an extrahepatic tumor; or (2) presence of a single small intrahepatic tumor. These 30 patients were retrospectively analyzed to calculate the percentage volume (%Volume) and the percentage function (%Function) of each lobe. The ratio between the %Function and %Volume (function-to-volume ratio) of each lobe was also calculated, and the ratios were compared between the 2 lobes. Furthermore, the correlations between the function-to-volume ratio and each of 2 liver parameters [lobe volume and diameter ratio of the left portal vein to the right portal vein (LPV-to-RPV diameter ratio)] were investigated.

RESULTS: The median values of %Volume and %Function were 62.6% and 67.1% in the right lobe, with %Function being significantly higher than %Volume (P < 0.01). The median values of %Volume and %Function were 31.0% and 28.7% in the left lobe, with %Function being significantly lower than %Volume (P < 0.01). The function-to-volume ratios of the right lobe (1.04-1.14) were significantly higher than those of the left lobe (0.74-0.99) (P < 0.01). The function-to-volume ratio showed no significant correlation between the lobe volume in either lobe. In contrast, the function-to-volume ratio showed significant correlations with the LPV-to-RPV diameter ratio in both lobes (right lobe: negative correlation, r_s = -0.37, P = 0.048; left lobe: positive correlation, r_s = 0.71, P < 0.001). The function-to-volume ratio in the left lobe tended to be higher, and that in the right lobe tended to be lower, in accordance with the increase in the LPV-to-RPV diameter ratio.

CONCLUSION: CT/^99mTc-GSA SPECT fusion images demonstrated that the function of the left lobe was significantly decreased compared with that of the right lobe in non-cirrhotic livers.

Liver function testing with nuclear medicine techniques is coming of age

Liver function is a broad term, as the organ participates in a multitude of different physiological and biochemical processes, including metabolic, synthetic, and detoxifying functions. However, it is the function of the hepatocyte that is central to sustaining normal life and dealing with disease states. When the liver begins to fail in severely ill patients, it forecasts a terminal outcome. However, unlike the glomerular filtration rate which clearly quantifies the key renal function, at most practice sites, there is no clinically available quantitative test for liver function. Although it is commonplace to assess indirect evidence of that function (by measuring blood levels of its end products and by-products) and to detect an acute injury (by following rising transaminases), a widely available test that would directly measure hepatocellular function is lacking. This article reviews current knowledge on liver function studies and focuses on those nuclear medicine tests available to study the whole liver and regional liver function. The clinical application driving these tests, prediction of remnant liver function after partial hepatectomy for primary liver malignancy or metastatic disease, is addressed here in detail. The test was recently validated for this specific application and was shown to be better than the current standard of practice (computed tomography volumetry), particularly in patients with hepatic comorbidities like cirrhosis, steatosis, or cholestasis. Furthermore, early assessment of regional liver function increase after preoperative portal vein embolization becomes possible with this technology. The limiting factor to a wider acceptance of this test is based on the lack of clinical software that would allow calculation of liver function parameters. This article provides information that enables a clinical nuclear medicine facility to provide this test using readily available equipment. Furthermore, it addresses emerging clinical applications that are under investigation.

Fused 99m-Tc-GSA SPECT/CT imaging for the preoperative evaluation of postoperative liver function: can the liver uptake index predict postoperative hepatic functional reserve?

PURPOSE

To evaluate the role of hepatic asialoglycoprotein receptor analysis in the preoperative estimation of postoperative hepatic functional reserve.

METHODS

We obtained technetium-99m-diethylenetriaminepentaacetic acid-galactosyl human serum albumin (99mTc-GSA) SPECT/CT fusion images in 256 patients with liver disease scheduled for hepatic resection. The liver uptake value corrected for body surface area [LUV(BSA)] and liver uptake ratio (LUR) of the remnant were preoperatively estimated based on the fused images. These values were compared with the postoperative hepatic functional reserve.

RESULTS

Significant correlations were observed between LUV(BSA), LUR, and most conventional indicators of hepatic functional reserve. Postoperatively, nonpreserved liver functional reserve was observed in 15 of the 256 patients (5.8%). Remnant LUV(BSA) showed better correlation than remnant LUR or the other indicators. No patients with remnant LUV(BSA) above 28.0 manifested poor nonpreserved functional reserve. Using a LUV(BSA) of 27.0, it was possible to predict postoperative poor hepatic functional reserve at a sensitivity of 91%, specificity of 81%, and accuracy of 81% postoperatively. According to multivariate analysis, a low remnant LUV(BSA) was the only significant independent predictor of poor hepatic functional reserve.

CONCLUSIONS

Our 99mTc-GSA SPECT/CT fusion imaging method was clinically useful for evaluating regional hepatic function and for predicting postoperative hepatic functional reserve.

Portal vein embolization before liver resection: a systematic review

Purpose

This is a review of literature on the indications, technique, and outcome of portal vein embolization (PVE).

Methods

A systematic literature search on outcome of PVE from 1990 to 2011 was performed in Medline, Cochrane, and Embase databases.

Results

Forty-four articles were selected, including 1,791 patients with a mean age of 61 ± 4.1 years. Overall technical success rate was 99.3 %. The mean hypertrophy rate of the FRL after PVE was 37.9 ± 0.1 %. In 70 patients (3.9 %), surgery was not performed because of failure of PVE (clinical success rate 96.1 %). In 51 patients (2.8 %), the hypertrophy response was insufficient to perform liver resection. In the other 17 cases, 12 did not technically succeed (0.7 %) and 7 caused a complication leading to unresectability (0.4 %). In 6.1 %, resection was cancelled because of local tumor progression after PVE. Major complications were seen in 2.5 %, and the mortality rate was 0.1 %. A head-to-head comparison shows a negative effect of liver cirrhosis on hypertrophy response. The use of n-butyl cyanoacrylate seems to have a greater effect on hypertrophy, but the difference with other embolization materials did not reach statistical significance. No difference in regeneration is seen in patients with cholestasis or chemotherapy.

Conclusions

Preoperative PVE has a high technical and clinical success rate. Liver cirrhosis has a negative effect on regeneration, but cholestasis and chemotherapy do not seem to have an influence on the hypertrophy response. The use of n-butyl cyanoacrylate may result in a greater hypertrophy response compared with other embolization materials used.

Correction of liver displacement due to irregular respiration for SPECT images obtained using a multiple short-time acquisition with breath-holding technique

Recently, a new method for acquiring single photon emission computed tomography (SPECT) data during breath-holding with a high-speed rotation (HSR-SPECT) technique was applied to hepatic-function scintigraphy. This technique can suppress motion artifact caused by respiration. However, it is challenging to apply this technique to patients with respiratory problems. Our purpose in this study was to analyze projection data and correct liver displacement due to irregular respiration during technetium-99m-diethylenetriaminepentaacetic acid galactosyl human serum albumin ((99m)Tc-GSA) liver SPECT scans. We calculated cross-correlation functions (CCFs) for both intra- and inter-projections to correct irregular projections by shifting them in the longitudinal direction enough to maximize the CCFs. We integrated all of the shifted projections and created a synthesis projection which was used to reconstruct SPECT images. To confirm the effectiveness of our method, we did both a phantom study and a clinical retrospective review. In the phantom study, blurring artifacts due to displacement were reduced using our method. Post-processing using our method showed improvements in the normalized mean square error values ranging from 0.18 to 0.06. Furthermore, our method showed no disadvantage or miss-correction if we applied our method to data without displacement. In the clinical review, our method improved the image clarity for patients who could not repeat consistent respiration. In both the phantom simulation and the clinical application, the results showed the usefulness of our method. The efficiency of our method has the potential to reduce the displacement problem caused by respiration and provides excellent matching SPECT/CT fusion images.

Increase in future remnant liver function after preoperative portal vein embolization

BACKGROUND

Preoperative portal vein embolization (PVE) is performed in patients with insufficient future remnant liver (FRL) to allow safe resection. Although many studies have demonstrated an increase in FRL volume after PVE, little is known about the increase in FRL function. This study evaluated the increase in FRL function after PVE using (⁹⁹m) Tc-labelled mebrofenin hepatobiliary scintigraphy (HBS) with single photon emission computed tomography (SPECT) and compared this with the increase in FRL volume.

METHODS

In 24 patients, computed tomography volumetry and (⁹⁹m) Tc-labelled mebrofenin HBS with SPECT were performed before and 3-4 weeks after PVE to measure FRL volume, standardized FRL and FRL function. A hypothetical model was used to assess safe resectability after PVE. The limit for safe resection for FRL function was set at an uptake of 2·69 per cent per min per m². For FRL volume and standardized FRL, 25 or 40 per cent of total liver volume was used, depending on the presence of underlying liver disease.

RESULTS

After PVE, FRL function increased significantly more than FRL volume. The correlation between the increase in FRL volume and FRL function was poor. Using the hypothetical model, seven patients did not achieve a sufficient increase in FRL function to allow safe resection 3-4 weeks after PVE, compared with 12 and nine patients based on FRL volume and standardized FRL respectively.

CONCLUSION

The increase in FRL function after PVE is more pronounced than the increase in FRL volume, suggesting that the necessary waiting time until resection may be shorter than indicated by volumetric parameters.