Compartmental analysis of asialoglycoprotein receptor scintigraphy for quantitative measurement of liver function: a multicentre study

Deep learning-based attenuation correction method in 99mTc-GSA SPECT/CT hepatic imaging: a phantom study

This study aimed to evaluate a deep learning-based attenuation correction (AC) method to generate pseudo-computed tomography (CT) images from non-AC single-photon emission computed tomography images (SPECTNC) for AC in 99mTc-galactosyl human albumin diethylenetriamine pentaacetic acid (GSA) scintigraphy and to reduce patient dosage. A cycle-consistent generative network (CycleGAN) model was used to generate pseudo-CT images. The training datasets comprised approximately 850 liver phantom images obtained from SPECTNC and real CT images. The training datasets were then input to CycleGAN, and pseudo-CT images were output. SPECT images with real-time CT attenuation correction (SPECTCTAC) and pseudo-CT attenuation correction (SPECTGAN) were acquired. The difference in liver volume between real CT and pseudo-CT images was evaluated. Total counts and uniformity were then used to evaluate the effects of AC. Additionally, the similarity coefficients of SPECTCTAC and SPECTGAN were assessed using a structural similarity (SSIM) index. The pseudo-CT images produced a lower liver volume than the real CT images. SPECTCTAC exhibited a higher total count than SPECTNC and SPECTGAN, which were approximately 60% and 7% lower, respectively. The uniformities of SPECTCTAC and SPECTGAN were better than those of SPECTNC. The mean SSIM value for SPECTCTAC and SPECTGAN was 0.97. We proposed a deep learning-based AC approach to generate pseudo-CT images from SPECTNC images in 99mTc-GSA scintigraphy. SPECTGAN with AC using pseudo-CT images was similar to SPECTCTAC, demonstrating the possibility of SPECT/CT examination with reduced exposure to radiation.

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.

Estimation of post-therapeutic liver reserve capacity using 99mTc-GSA scintigraphy prior to carbon-ion radiotherapy for liver tumors

BACKGROUND

There is currently no established imaging method for assessing liver reserve capacity prior to carbon-ion radiotherapy (CIRT) for liver tumors. In order to perform safe CIRT, it is essential to estimate the post-therapeutic residual reserve capacity of the liver.

PURPOSE

To evaluate the ability of pre-treatment 99mTc-galactosyl human serum albumin (99mTc-GSA) scintigraphy to accurately estimate the residual liver reserve capacity in patients treated with CIRT for liver tumors.

MATERIALS AND METHODS

This retrospective study evaluated patients who were performed CIRT for liver tumors between December 2018 and September 2020 and underwent 99mTc-GSA scintigraphy before and 3 months after CIRT, and gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced MRI within 1 month before CIRT were evaluated. The maximal removal rate of 99mTc-GSA (GSA-Rmax) was analyzed for the evaluation of pre-treatment liver reserve capacity. Then, the GSA-Rmax of the estimated residual liver (GSA-RL) was calculated using liver SPECT images fused with the Gd-EOB-DTPA-enhanced MRI. GSA-RL before CIRT and GSA-Rmax at 3 months after CIRT were compared using non-parametric Wilcoxon signed-rank test and linear regression analysis.

RESULTS

Overall, 50 patients were included (mean age ± standard deviation, 73 years ± 11; range, 29-89 years, 35 men). The median GSA-RL was 0.393 [range, 0.057-0.729] mg/min, and the median GSA-Rmax after CIRT was 0.369 [range, 0.037-0.780] mg/min (P = .40). The linear regression equation representing the relationship between the GSA-RL and GSA-Rmax after CIRT was y = 0.05 + 0.84x (R2 = 0.67, P < .0001). There was a linear relationship between the estimated and actual post-treatment values for all patients, as well as in the group with impaired liver reserve capacity (y = - 0.02 + 1.09x (R2 = 0.62, P = .0005)).

CONCLUSIONS

99mTc-GSA scintigraphy has potential clinical utility for estimating the residual liver reserve capacity in patients undergoing carbon-ion radiotherapy for liver tumors.

TRIAL REGISTRATION

UMIN000038328, https://center6.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000043545 .

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.

Functional transition: Inconsistently parallel to the increase in future liver remnant volume after preoperative portal vein embolization

BACKGROUND

Preoperative portal vein embolization (PVE) is a widely used strategy to enable major hepatectomy in patients with insufficient liver remnant. PVE induces hypertrophy of the future liver remnant (FLR) and a shift of the functional reserve to the FLR. However, whether the increase of the FLR volume (FLRV) corresponds to the functional transition after PVE remains unclear.

AIM

To investigate the sequential relationship between the increase in FLRV and functional transition after preoperative PVE using 3-dimensional (3D) computed tomography (CT) and ^99mTc-galactosyl-human serum albumin (^99mTc-GSA) single-photon emission computed tomography (SPECT) fusion images.

METHODS

Thirty-three patients who underwent major hepatectomy following PVE at the Department of Gastroenterological Surgery I, Hokkaido University Hospital between October 2013 and March 2018 were enrolled. Three-phase dynamic multidetector CT and ^99mTc-GSA SPECT scintigraphy were performed at pre-PVE, and at 1 and 2 wk after PVE; 3D ^99mTc-GSA SPECT CT-fused images were constructed from the Digital Imaging and Communications in Medicine data using 3D image analysis system. Functional FLRV (FFLRV) was defined as the total liver volume × (FLR volume counts/total liver volume counts) on the 3D ^99mTc-GSA SPECT CT-fused images. The calculated FFLRV was compared with FLRV.

RESULTS

FFLRV increased by a significantly larger extent than FLRV at 1 and 2 wk after PVE (P < 0.01). The increase in FFLRV and FLRV was 55.1% ± 41.6% and 26.7% ± 17.8% (P < 0.001), respectively, at 1 wk after PVE, and 64.2% ± 33.3% and 36.8% ± 18.9% (P < 0.001), respectively, at 2 wk after PVE. In 3 of the 33 patients, FFLRV levels decreased below FLRV at 2 wk. One of the three patients showed rapidly progressive fatty changes in FLR. The biopsy at 4 wk after PVE showed macro- and micro-vesicular steatosis of more than 40%, which improved to 10%. Radical resection was performed at 13 wk after PVE. The patient recovered uneventfully without any symptoms of pos-toperative liver failure.

CONCLUSION

The functional transition lagged behind the increase in FLRV after PVE in some cases. Evaluating both volume and function is needed to determine the optimal timing of hepatectomy after PVE.

Hemostatic Alterations in Patients With Cirrhosis: From Primary Hemostasis to Fibrinolysis

In the setting of liver cirrhosis (LC), profound hemostatic changes occur, which affect primary hemostasis, coagulation, and fibrinolysis. They involve prohemorrhagic and prothrombotic alterations at each of these steps. Patients with cirrhosis exhibit multifactorial thrombocytopenia and in vitro thrombocytopathy, counterbalanced by increased von Willebrand factor. The resultant shift is difficult to assess, but overall these changes probably result in a rebalanced primary hemostasis. Concerning coagulation, the reduced activity of coagulation factors is counterbalanced by an increase in factor VIII (produced by liver sinusoidal endothelial cells), a decrease of the natural anticoagulants, and complex changes, including changes in circulating microparticles, cell-free DNA, and neutrophil extracellular traps. Overall, these alterations result in a procoagulant state. As for fibrinolysis, increased tissue-type and urokinase-type plasminogen activators, a relatively decreased plasminogen activator inhibitor 1, and decreased levels of thrombin-activatable fibrinolysis inhibitor and α2-antiplasmin are counterbalanced by decreased plasminogen and a decreased fibrin clot permeability. Whether and how these changes shift fibrinolysis remains to be determined. Overall, the current consensus is that in patients with cirrhosis, the hemostasis is shifted toward a procoagulant state. We review the published evidence for the concept of LC as a prothrombotic state, discuss discordant data, and highlight the impact of the underlying cause of LC on the resultant imbalance.

Significance of the preoperative regional maximal removal rate of technetium-99m-galactosyl human serum albumin in the future remnant liver: a sequential study of regional maximal removal rate of technetium-99m-galactosyl human serum albumin in the whole liver

BACKGROUND

The relationship between posthepatectomy complications and liver functional parameters was preliminary reported in a pilot study. The present study sequentially evaluated the clinical significance of maximal removal rate of technetium-99m-galactosyl human serum albumin (GSARmax) in the future remnant liver (rGSARmax) in patients to predict posthepatectomy complications.

METHODS

Between 2010 and August 2017, GSARmax, rGSARmax, their difference (Dif), and the rGSARmax to GSARmax ratio were examined in 247 additional patients who underwent hepatectomy for liver and biliary diseases. Hepatectomy-related postoperative complications (i.e. long-term ascites, intra-abdominal infection, and hepatic failure) occurred in 73 (29.6%) patients.

RESULTS

The median and mean preoperative GSARmax values were 0.477 and 0.498±0.166 mg/min, respectively; rGSARmax values were 0.341 and 0.366±0.145 mg/min, respectively; Dif values were 0.105 and 0.132±0.111 mg/min, respectively; and the rGSARmax to GSARmax ratio values were 0.774 and 0.746±0.177, respectively. Among these, the GSARmax and rGSARmax values were significantly correlated with the liver functional parameters ICGR15, LHL15, HH15, prothrombin activity, serum hyaluronic acid level, and platelet count (all P<0.01). The rGSARmax values were significantly lower in patients with long-term ascites (P<0.05), and the predictive cutoff values of rGSARmax were 0.290 mg/min; however, the multivariate logistic regression analysis showed that rGSARmax was not independently related to long-term ascites.

CONCLUSION

When accompanied by other functional liver reserve parameters, rGSARmax seemed to be an alternative liver functional parameter related to ascites.

[68Ga]NOTA-Galactosyl Human Serum Albumin: a Tracer for Liver Function Imaging with Improved Stability

Purpose

Non-invasive techniques allowing quantitative determination of the functional liver mass are of great interest for patient management in a variety of clinical settings. Recently, we presented [⁶⁸Ga]DTPA-GSA to target the hepatic asialoglycoprotein receptor for this purpose. Here, we introduce [⁶⁸Ga]NOTA-GSA to improve metabolic stability of the radiopharmaceutical and compare the imaging properties with [⁶⁸Ga]DTPA-GSA.

Procedures

Labeling of the compounds was carried out at room temperature using 1.9 M sodium acetate as buffer. For quality control, thin-layer, high-performance liquid, and size exclusion chromatographies were used. Metabolic stability was studied in rat and human serums. For in vivo evaluation, Fischer rats were scanned by positron emission tomography and magnetic resonance imaging and subsequently sacrificed for biodistribution studies. Time activity curves (TACs) for heart and liver were generated and corresponding parameters (T₅₀, T₉₀, LHL15, HH15) were calculated.

Results

[⁶⁸Ga]NOTA-GSA can be produced in high radiochemical yield and purity (>95 %) within 15 min. Stability studies revealed almost no metabolite formation over the 2-h observation period. Analysis of the TACs showed comparable results for most of the investigated parameters. The only significant difference was found in the T₉₀ value, where [⁶⁸Ga]NOTA-GSA showed slower uptake in comparison with ⁶⁸Ga-DTPA-GSA (123 ± 10 vs. 89 ± 3 s, p < 0.01).

Conclusions

[⁶⁸Ga]NOTA-GSA showed a significant increase of the metabolic stability and in most organs lower background activity. However, comparison of LHL15 and HH15 indicates that the increased stability did not further improve the diagnostic value. Thus, [⁶⁸Ga]NOTA-GSA and [⁶⁸Ga]DTPA-GSA can be used equivalent for imaging hepatic function with positron emission tomography.

Prediction of Posthepatectomy Liver Failure Proposed by the International Study Group of Liver Surgery: Residual Liver Function Estimation With 99mTc-Galactosyl Human Serum Albumin Scintigraphy

PURPOSE

The International Study Group of Liver Surgery (ISGLS) proposed a definition and grading system for posthepatectomy liver failure (PHLF). We evaluated the usefulness of residual liver function estimation using Tc-galactosyl human serum albumin (Tc-GSA) for the prediction of PHLF.

METHODS

Patients with liver tumors (n = 136) and scheduled for hepatectomy underwent Tc-GSA scintigraphy. Based on their imaging data, the maximal GSA removal rate (GSA-Rmax)was calculated using multicompartment analysis. We also calculated GSA-Rmax in the predicted residual liver (GSA-RL) whose volume was determined on computed tomography (CT) scans. We compared the age, sex, 15-minute indocyanine green retention rate; albumin, bilirubin, hyaluronic acid, and type 4 collagen levels; the Child-Pugh classification; residual liver volume; residual liver percentage; GSA-Rmax; and GSA-RL in patients with and without PHLF. Univariate and multivariate logistic analyses were used for statistical assessments.

RESULTS

Of 136 patients, 17 (12.5%) met the ISGLS criteria for PHLF (ISGLS-PHLF). There was a statistically significant difference in the age, albumin level, Child-Pugh classification, residual liver volume, residual liver percentage, GSA-Rmax, and GSA-RL between patients with and without PHLF. Based on multivariate analysis, GSA-RL and the residual liver volume were significant independent predictors of ISGLS-PHLF (P = 0.004 and P = 0.038, respectively). The odds ratio was 149423 for GSA-RL and 1.003 for the residual liver volume.

CONCLUSIONS

GSA-RL calculated using Tc-GSA scintigraphy was the most useful independent predictor for ISGLS-PHLF.

Preoperative regional maximal removal rate of technetium-99m-galactosyl human serum albumin is correlated with liver functional parameters, but did not predict postoperative morbidity

BACKGROUND

Recently, posthepatectomy complications have been predicted by advances of new liver functional parameters, and the technetium-99m-galactosyl human serum albumin (GSA) liver scintigraphy has been applied widely for this purpose. We evaluated the clinical significance of the regional maximal removal rate (GSA-Rmax) in patients with various liver diseases as predictors of posthepatectomy complications.

PATIENTS AND METHODS

Between 2012 and March 2016, we examined 200 patients who underwent hepatectomy for liver and biliary diseases. The patients' background liver conditions included chronic viral liver diseases in 147 patients, normal liver in 44 patients, and others in nine patients. Hepatectomy-related postoperative complications (i.e. long-term ascites, intra-abdominal infection, and hepatic failure) occurred in 69 (35%) patients. A multivariate logistic analysis was carried out to detect the predictive parameters for complications.

RESULTS

The median and mean preoperative GSA-Rmax was 0.420 and 0.448±0.148 mg/min, respectively. The GSA-Rmax was significantly correlated with liver functional parameters of ICGR15, LHL15, HH15, platelet count, prothrombin activity, and serum hyaluronic acid level (P<0.01), and was significantly correlated with postoperative total bilirubin level and C-reactive protein level (P<0.05). With respect to patient outcomes, GSA-Rmax was significantly lower in patients with long-term ascites (P<0.05). The predictive cutoff value for posthepatectomy long-term ascites for GSA-Rmax was 0.421 mg/min. However, the multivariate logistic regression analysis identified that a higher serum hyaluronic acid level and a lower platelet count were significant, independent factors, but not lower GSA-Rmax.

CONCLUSION

GSA-Rmax is one of the liver functional parameters and is a complementary parameter to predict postoperative hyperbilirubinemia, inflammatory responses, and ascites when Tc-GSA scintigraphy is performed.

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.

Preoperative maximal removal rate of technetium-99m-galactosyl-human serum albumin of the remnant liver is associated with postoperative tumor relapse in hepatitis C virus-related hepatocellular carcinoma

BACKGROUND

Prognosis in patients with hepatocellular carcinoma (HCC) is not only influenced by tumor-related factors but also by the background liver functions. The maximal removal rate of technetium-99m-galactosyl human serum albumin (GSA-Rmax) of the remnant liver (rGSA-Rmax) is a useful candidate for predicting the liver function and clarifying the relationship between the remnant liver functional reserve and tumor-free survival in patients who have undergone hepatectomy.

PATIENTS AND METHODS

One hundred and sixty-five patients with HCC who underwent curative hepatectomy were divided into three groups of hepatitis B virus (B-HCC; n=42), hepatitis C virus (C-HCC, n=58), and non-B, non-C (NBNC-HCC, n=65). The relationship between rGSA-Rmax and survival was examined by univariate and multivariate analyses.

RESULTS

In the C-HCC group, the albumin, or LHL15, level was significantly lower, and alanine aminotransferase, ICGR15, and the prevalence of grade B liver damage were significantly higher than other two groups (P<0.05). GSA-Rmax or rGSA-Rmax was not different between the three groups. Lower GSA-Rmax and rGSA-Rmax were only significantly associated with lower tumor-free survival in the C-HCC group by the univariate analysis (P<0.05) but not significantly by the multivariate analysis.

CONCLUSION

GSA-Rmax and rGSA-Rmax reflect the severity of liver dysfunction and furthermore, the lower rGSA-Rmax is useful as a complementary factor to predict the early HCC recurrence after hepatectomy.

Index of convexity: A novel method for assessing liver functional reserve using technetium-99m-galactosyl human serum albumin liver scintigraphy

Preoperative evaluation of liver functional reserve is important in hepatobiliary surgery. Although the indocyanine green retention rate at 15 minutes (ICG-R15) is the gold standard for this purpose, a new method without technical complexity would be preferable. We assessed the usefulness of the previously established index of convexity (IOC). In total, 159 consecutive patients who underwent both technetium-99m-galactosyl human serum albumin (^99mTc-GSA) scintigraphy and the ICG-R15 were included. Correlation coefficients between indices from ^99mTc-GSA scintigraphy and blood examinations including ICG-R15 were evaluated, and a conversion formula from the IOC to the ICG-R15 was established. The IOC was calculated as [L(15) × 2 - L(3) - L(27)] / [L(27) - L(3)], where L(t) indicates the radiation counts within the whole liver at t minutes after ^99mTc-GSA injection. The IOC showed a significantly stronger correlation with the ICG-R15 (r = -0.532, p < 0.001) than the index of blood clearance (HH15) and the receptor index (LHL15). A formula for estimating ICG-R15 from IOC was "ICG-R15 = -31.0 × IOC + 30.1". In conclusion, the IOC is a better index for evaluating preoperative liver functional reserve than the conventional indices. A formula for estimating ICG-R15 from the IOC will be useful.

Significance of functional hepatic resection rate calculated using 3D CT/99mTc-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)/^99mTc-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 ^99mTc-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/^99mTc-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.

Advances in preoperative assessment of liver function

BACKGROUND

Postoperative liver failure remains a life-threatening complication. Preoperative evaluation of liver function is essential in reducing the complications after hepatectomy. However, it is difficult to accurately evaluate liver function before surgery because of the limitations of the liver function tests available. Recent advances in liver function tests improved the ability to assess liver function. The present review was to analyze these methods and their advantages.

DATA SOURCES

MEDLINE was searched using the terms of "liver function test", "liver function evaluation" and "galactosyl serum albumin". Relevant articles published in English and Chinese from 1961 to 2014 were reviewed.

RESULTS

Although serological tests are used frequently in practice, they reflect the degree of total liver damage or function, not the remnant of liver function. Child-Pugh score and model for end-stage liver disease (MELD) score assess whole liver function, and are particularly useful in determining whether patients with hepatocellular carcinoma and cirrhosis are candidates for resection or transplantation, but cannot determine the safe extent or removal. The indocyanine green and other metabolic quantitative liver function tests can evaluate functional hepatocytes, making them more accurate in predicting liver function. Computed tomography (CT) volumetry can provide anatomic information on the remnant liver volume but not on functional volume. 99mTc-galactosyl serum albumin scintigraphy, combined with single photon emission computed tomography, CT and three-dimensional reconstruction, may be a better quantitative measure of liver function, especially of remnant liver function.

CONCLUSIONS

Tests used to evaluate liver functional reserve and to predict surgical risk have limitations. 99mTc-galactosyl serum albumin scintigraphy, which can more accurately evaluate the whole and regional liver function, may be promising in predicting resection margins and risks of liver failure.

Comparison of Tc-99m GSA scintigraphy and CT volumetry for evaluation in portal vein embolization

PURPOSE

To determine the correlation of the rate of change of each future remnant liver (FRL) before and after portal vein embolization (PVE), by CT volumetry and Tc-99m galactosyl human serum albumin scintigraphy (GSA scintigraphy).

MATERIAL AND METHODS

From December 2007 to July 2012, ten patients underwent PVE before hepatic resection. CT volumetry and GSA scintigraphy were performed before and after PVE. The FRL was divided at Cantlie's line for CT volumetry, and volume change rates before and after PVE were calculated. The maximum removal rate (Rmax) was calculated using a radiopharmacokinetic model in GSA scintigraphy. The FRL Rmax change rates before and after PVE were calculated. The correlation between the volume change rates and the Rmax change rates was analyzed.

RESULTS

The FRL volume change rate was 1.28 ± 0.26 (mean ± SD); the FRL hypertrophied in all patients significantly (p = 0.005). The FRL Rmax change rate was 1.66 ± 0.75; excluding one patient, there was significant FRL Rmax increase (p = 0.022). Although both increased significantly, no correlation between the volume change rate and the Rmax change rate was observed.

CONCLUSION

No correlation was observed between the FRL volume rate and the Rmax rate.

Measuring hepatic functional reserve using low temporal resolution Gd-EOB-DTPA dynamic contrast-enhanced MRI: a preliminary study comparing galactosyl human serum albumin scintigraphy with indocyanine green retention

OBJECTIVE

To investigate if tracer kinetic modelling of low temporal resolution dynamic contrast-enhanced (DCE) MRI with Gd-EOB-DTPA could replace technetium-99 m galactosyl human serum albumin (GSA) single positron emission computed tomography (SPECT) and indocyanine green (ICG) retention for the measurement of liver functional reserve.

METHODS

Twenty eight patients awaiting liver resection for various cancers were included in this retrospective study that was approved by the institutional review board. The Gd-EOB-DTPA MRI sequence acquired five images: unenhanced, double arterial phase, portal phase, and 4 min after injection. Intracellular contrast uptake rate (UR) and extracellular volume (Ve) were calculated from DCE-MRI, along with the ratio of GSA radioactivity of liver to heart-plus-liver and per cent of cumulative uptake from 15-16 min (LHL15 and LU15, respectively) from GSA-scintigraphy. ICG retention at 15 min, Child-Pugh cirrhosis score (CPS) and postoperative Inuyama fibrosis criteria were also recorded. Statistical analysis was with Spearman rank correlation analysis.

RESULTS

Comparing MRI parameters with the reference methods, significant correlations were obtained for UR and LHL15, LU15, ICG15 (all 0.4-0.6, P < 0.05); UR and CPS (-0.64, P < 0.001); Ve and Inuyama (0.44, P < 0.05).

CONCLUSION

Measures of liver function obtained by routine Gd-EOB-DTPA DCE-MRI with tracer kinetic modelling may provide a suitable method for the evaluation of liver functional reserve.

KEY POINTS

• Magnetic resonance imaging (MRI) provides new methods of measuring hepatic functional reserve. • DCE-MRI with Gd-EOB-DTPA offers the possibility of replacing scintigraphy. • The analysis method can be used for preoperative liver function evaluation.

Usefulness of Tc-99m-GSA scintigraphy for liver surgery

Postoperative mortality remains high after hepatectomy compared with other types of surgery in patients who have cirrhosis or chronic hepatitis. Although there are several useful perioperative indicators of liver dysfunction, no standard markers are available to predict postoperative liver failure in patients with hepatocellular carcinoma (HCC) undergoing hepatectomy. The best preoperative method for evaluating the hepatic functional reserve of patients with HCC remains unclear, but technetium-99m diethylenetriamine pentaacetic acid galactosyl human serum albumin ((99m)Tc-GSA) scintigraphy is a candidate. (99m)Tc-GSA is a liver scintigraphy agent that binds to the asialoglycoprotein receptor, and can be used to assess the functional hepatocyte mass and thus determine the hepatic functional reserve in various physiological and pathological states. The maximum removal rate of (99m) Tc-GSA (GSA-Rmax) calculated by using a radiopharmacokinetic model is correlated with the severity of liver disease. There is also a significant difference of GSA-Rmax between patients with chronic hepatitis and persons with normal liver function. Regeneration of the remnant liver and recurrence of hepatitis C virus infection in the donor organ after living donor liver transplantation have also been investigated by (99m)Tc-GSA scintigraphy. This review discusses the usefulness of (99m)Tc-GSA scintigraphy for liver surgery.

Effects of late evening snack including branched-chain amino acid on the function of hepatic parenchymal cells in patients with liver cirrhosis

AIM

  A late evening snack (LES) improves protein-energy malnutrition due to overnight starvation and the catabolic state in patients with liver cirrhosis. Our aim was to examine whether LES including a branched-chain amino acid (BCAA) could maintain hepatic reserve and the function of hepatic parenchymal cells in patients with liver cirrhosis, including those in the early stage of disease.

METHODS

  Seventeen patients with liver cirrhosis received LES with a BCAA-enriched nutrient mixture. During the study period, each patient was instructed on energy and protein intake. Indicators of liver function measured at 6 months included maximum asialoscintigraphic removal (Rmax: indicator of total liver receptors), asialoscintigraphic imaging grade, serum albumin, ammonia, tyrosine and BTR (molar ratio of branched-chain amino acids to tyrosine).

RESULTS

  Serum albumin levels, BTR and tyrosine levels of the 17 patients were significantly improved after nutrient treatment. In patients with Rmax of 0.2 or higher, serum albumin level and tyrosine level were significantly improved.

CONCLUSION

  LES with BCAA-enriched nutrient therapy can improve protein malnutrition in patients with liver cirrhosis, and is more useful in the early stages of liver cirrhosis in improving hepatic parenchymal cell mass.

Quantitative analysis of liver function using superparamagnetic iron oxide- and Gd-EOB-DTPA-enhanced MRI: comparison with Technetium-99m galactosyl serum albumin scintigraphy

PURPOSE

To examine whether or not the parameters regarding the signal intensity of the liver parenchyma on superparamagnetic iron oxide (SPIO)- and gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced MRI are correlated with the parameters of Technetium-99m galactosyl serum albumin ((99m)Tc-GSA) scintigraphy.

MATERIALS AND METHODS

This retrospective study consisted of 55 and 33 patients who underwent SPIO- and Gd-EOB-DTPA-enhanced MRI in addition to (99m)Tc-GSA scintigraphy, respectively. For each patient, we calculated Pre R2* and Pre R2, which are equivalent to R2* (=1/T2*) and R2 (=1/T2) values of the liver parenchyma; ΔR2* and ΔR2, which represent differences in R2* and R2 values of the liver parenchyma before and after administration of SPIO; and the increase rates of both the liver-to-spleen signal intensity ratio (LSR) and the liver-to-major psoas muscle signal intensity ratio (LMR) on the hepatobiliary phase compared with the precontrast image. For (99m)Tc-GSA scintigraphy, the receptor index LHL15 and the blood clearance index HH15 were recorded.

RESULTS

Regression analysis showed a moderate correlation between Pre R2* and LHL15 (P<0.05). Mild to moderate correlations were also obtained between any combination of ΔR2* and ΔR2 on the one hand, and LHL15 and HH15 on the other (P<0.05). There were moderate correlations between any combination of increase rates of LSR and LMR on the one hand, and LHL15 and HH15 on the other (P<0.05-0.001).

CONCLUSION

Pre R2*, ΔR2*, ΔR2 and the increase rates of LSR and LMR could be used as quantitative indicators of liver function.

Preoperative tumor marker doubling time is a useful predictor of recurrence and prognosis after hepatic resection of hepatocellular carcinoma

BACKGROUND AND OBJECTIVES

It is important to identify prognostic factors in patients with hepatocellular carcinoma (HCC) before hepatectomy. No previous studies have addressed the predictive efficacy of the preoperative doubling times of alpha-fetoprotein (AFP) and protein induced by vitamin K absence (PIVKA-II).

METHODS

A total of 210 HCC patients who underwent a hepatic resection between 1998 and 2006 were prospectively evaluated. Serum AFP and PIVKA-II levels were measured at least twice before surgery to calculate the doubling times. Nineteen clinical factors that can be examined preoperatively, including the doubling times of AFP and PIVKA-II were investigated to identify prognostic factors for disease-free and overall survival after hepatectomy.

RESULTS

There was no relationship between preoperative levels and doubling times of AFP and PIVKA-II. In a multivariate analysis, patients with a doubling time of AFP ≤30 days and PIVKA-II ≤16 days showed a significantly worse disease-free (P = 0.02, P = 0.03, respectively) and overall survival (P < 0.0001, P = 0.03, respectively).

CONCLUSIONS

In HCC patients, the doubling times of preoperative serum AFP or PIVKA-II levels are useful tools to predict early postoperative recurrence and a poor prognosis.

Can imaging modalities diagnose and stage hepatic fibrosis and cirrhosis accurately?

The accurate diagnosis and staging of hepatic fibrosis is crucial for prognosis and treatment of liver disease. The current gold standard, liver biopsy, cannot be used for population-based screening, and has well known drawbacks if used for monitoring of disease progression or treatment success. Our objective was to assess performance and promise of radiologic modalities and techniques as alternative, noninvasive assessment of hepatic fibrosis. A systematic review was conducted. Six hundred twenty-eight studies were identified via electronic search. One hundred fifty-three papers were reviewed. Most described techniques that could differentiate between cirrhosis or severe fibrosis and normal liver. Accurate staging of fibrosis or diagnosis of mild fibrosis was often not achievable. Ultrasonography is the most common modality used in the diagnosis and staging of hepatic fibrosis. Elastographic measurements, either ultrasonography-based or magnetic resonance-based, and magnetic resonance diffusion weighted imaging, show the most promise for accurate staging of hepatic fibrosis. Most currently available imaging techniques can detect cirrhosis or significant fibrosis reasonably accurately. However, to date only magnetic resonance elastography has been able to stage fibrosis or diagnose mild disease. Utrasonographic elastography and magnetic resonance diffusion weighted appear next most promising.

Usefulness of TC-99M GSA liver scintigraphy for the assessment of recurrent hepatitis C after living-donor liver transplantation: a case report

BACKGROUND AND AIMS

Recurrence of hepatitis C after living-donor liver transplantation was investigated using technetium-99m-diethylenetriaminepentaacetic acid-galactosyl human serum albumin (Tc-99m-GSA) liver scintigraphy.

METHODS

A 55-year-old woman with cirrhosis due to chronic hepatitis C virus (HCV) infection underwent liver transplantation with a graft from her husband. Scintigraphy was used to determine the hepatic uptake ratio of the tracer corrected for disappearance from the blood, as well as the maximal removal rate of the tracer by hepatocytes, as parameters of hepatic functional reserve.

RESULTS

Conventional liver function parameters and the graft volume (computed tomography) were almost unchanged up to 18 months after transplantation. Serum HCV RNA was elevated from 3 months after transplantation, and was twofold higher at 12 months compared with 6 months. At 18 months postoperatively, liver biopsy showed an increase of histologic activity, and there was also evidence of recurrent hepatitis C. The corrected hepatic uptake ratio and maximal removal rate were decreased at 3 months postoperatively, and thereafter remained low.

CONCLUSIONS

The decrease of scintigraphic parameters at 3 months after transplantation suggested recurrent hepatitis C affecting the graft. Tc-99m-GSA liver scintigraphy is a useful noninvasive method for evaluating graft functional reserve.

Usefulness of TC-99M GSA liver scintigraphy for the evaluation of liver regeneration in donors after living-donor liver transplantation

BACKGROUND AND AIMS

We evaluated the impact of steatosis on regeneration and function of the remnant liver by using technetium-99m-diethylenetriaminepentaacetic acid-galactosyl human serum albumin scintigraphy.

METHODS

Twelve living donors were classified into groups with or without mild hepatic steatosis according to the liver-to-spleen attenuation ratio on computed tomography: six donors had a ratio > or = 1.2 (control group) and six had a ratio < 1.20 (fatty liver group). Scintigraphy was performed to determine the hepatic uptake ratio of the tracer (corrected for disappearance from the blood) and the maximum removal rate of the tracer by hepatocytes as parameters of the hepatic functional reserve.

RESULTS

The fatty liver group had a significantly lower corrected hepatic uptake ratio and removal rate compared with the control group at 6 and 12 months after partial hepatectomy. The regenerated liver volume estimated by scintigraphy did not differ significantly between the two groups at any time.

CONCLUSIONS

Because donors with mild hepatic steatosis showed impaired liver regeneration at 1 year after partial hepatectomy, management of these donors requires more care.

Differential receptor targeting of liver cells using 99mTc-neoglycosylated human serum albumins

Neolactosyl human serum albumin (LSA) targets asialoglycoprotein receptor and shows high liver uptake due to accumulation in hepatocytes. Although neomannosyl human serum albumin (MSA) also shows high liver uptake, it has been reported to be taken up by Kupffer cells and endothelial cells. We compared the biological properties of LSA and MSA. 99mTc-LSA and 99mTc-MSA biodistribution in mice were investigated after intravenous injection. In vivo localization of rhodaminisothiocyanate (RITC)-LSA and fluoresceineisothiocyanate (FITC)-MSA were investigated in mouse liver. Excretion routes of 99mTc-LSA and 99mTc-MSA metabolites were examined. Both 99mTc-LSA and 99mTc-MSA showed high liver uptakes. RITC-LSA was taken up by hepatocytes whereas FITC-MSA was taken up by Kupffer cells and endothelial cells. 99mTc-MSA showed higher spleen and kidney uptakes than 99mTc-LSA. 99mTc-LSA metabolites excreted in urine and feces accounted for 44.4 and 50.0% of 99mTc-LSA injected, respectively, while 99mTc-MSA metabolites accounted for 51.5 and 10.3%, respectively. In conclusion, LSA is specifically taken up by hepatcytes while MSA by Kupffer cells and endothelial cells. After taken up by the liver, LSA is metabolized by the hepatocytes and then excreted through both the hepatobiliary tract and kidney, whereas MSA is metabolized by Kupffer cells and endoghelial cells and then excreted mainly through the kidney.

Liver regeneration in donors evaluated by Tc-99m-GSA scintigraphy after living donor liver transplantation

The impact of hepatic steatosis on regeneration of the remnant liver after living donor liver transplantation is unclear. We evaluated the impact of steatosis on regeneration and function of the remnant liver by using technetium-99m-diethylenetriaminepentaacetic acid-galactosyl human serum albumin scintigraphy. Twelve living donors were classified into groups with or without mild hepatic steatosis according to the liver-to-spleen attenuation ratio on computed tomography: 6 donors had a ratio >or= 1.20 (control group) and 6 donors had a ratio < 1.20 (fatty liver group). Scintigraphy was performed to determine the hepatic uptake ratio of the tracer (corrected for disappearance from the blood) and the maximum removal rate of the tracer by hepatocytes as parameters of the hepatic functional reserve. The fatty liver group had a significantly lower corrected hepatic uptake ratio and removal rate compared with the control group at 6 and 12 months after partial hepatectomy. These parameters were decreased at 1 month after surgery in both groups. However, both parameters returned more rapidly to prehepatectomy levels in the control group. The regenerated liver volume estimated by scintigraphy did not differ significantly between the two groups at any time. Liver scintigraphy may be useful for evaluating the regeneration of functioning hepatocytes. Because donors with mild hepatic steatosis showed impaired liver regeneration at 1 year after partial hepatectomy, management of these donors requires more care.

Preoperative Assessment of Congestive Liver Dysfunction Using Technetium-99 m Galactosyl Human Serum Albumin Liver Scintigraphy in Patients with Severe Valvular Heart Disease

BACKGROUND

Severe valvular heart disease is often complicated by congestive liver dysfunction, which greatly compromises the operative results. We evaluated congestive liver dysfunction by a novel approach using technetium-99 m galactosyl human serum albumin ((99m)Tc-GSA) with liver scintigraphy.

METHODS

Between 1998 and 2004, we performed scintigraphy accompanied by (99m)Tc-GSA in 28 patients who had valvular heart disease with moderate-to-severe tricuspid regurgitation and who showed symptoms of right heart failure. Based on the results, we calculated a receptor index (LHL15) and an index of blood clearance (HH15) and assessed the correlation between these factors and postoperative liver dysfunction, defined as the maximum serum total bilirubin level (max T-bil) as >2.0 mg/dl.

RESULTS

Nineteen patients, including four who died in hospital, had postoperative liver dysfunction. The level of HH15 was significantly higher and the level of cholinesterase was significantly lower (P < 0.05) in patients with liver dysfunction than in those without liver dysfunction. Multivariate logistic regression analysis identified HH15 as the most sensitive indicator of postoperative hepatic dysfunction.

CONCLUSIONS

The level of HH15 calculated using scintigraphy with (99m)Tc-GSA is a clinically useful predictor of postoperative liver dysfunction in patients with severe valvular disease.

Recurrent hepatitis C after living donor liver transplantation detected by Tc-99m GSA liver scintigraphy

Recurrence of hepatitis C virus (HCV) after living donor liver transplantation was investigated using technetium-99m- diethylenetriaminepentaacetic acid-galactosyl human serum albumin (Tc-99m-GSA) liver scintigraphy. Four patients with decompensated cirrhosis due to HCV infection were retrospectively reviewed in this study. Scintigraphy was performed to determine the hepatic uptake ratio of the tracer corrected for disappearance from the blood, as well as the maximal removal rate of the tracer by hepatocytes, as parameters of hepatic functional reserve. In all patients, serum HCV ribonucleic acid (RNA) was detected 3 months after transplantation. The corrected hepatic uptake ratio and removal rate showed little change after transplantation in two patients without the recurrence of HCV infection. In another two patients, these levels were decreased at 3 months after transplantation. In one patient, recurrent HCV infection was diagnosed by confirmatory histologic examination at 12 months after transplantation. In the other patient, both levels declined further at 8 months. Although treatment was initiated with a combination of interferon plus ribavirin, this patient died of progressive hepatic failure. In conclusion, a decrease in scintigraphic parameters at 3 months after transplantation suggests recurrent HCV infection affecting the graft. Tc-99m-GSA liver scintigraphy is a useful noninvasive method for evaluating graft functional reserve.

Preoperative assessment of liver function

At the present time, the decision to resect and the choice of the extent ofa hepatic resection are largely based on surgical judgment. The CP score is the best assessment tool we can now employ. There is uniform agreement that even segmental resections are not possible in the vast majority of Child Class B patients, CP score 7 to 9. The CP score can be augmented by radiographic testing, ICG retention testing, and by assessing tumor extent and the severity of the patient's cirrhosis at surgery. Surgeons need a simple means to assist with liver function evaluation--a test to augment the CP score. Although determining ICG retention is simple, it is questionable whether it adds to one's ability to define the poor-risk patient with better accuracy than the CP score. Abundant data exist to dispute the accuracy and reproducibility of ICG retention. That surgeons use it says more about the fervent desire to find a test that supports clinical judgment in these difficult patients than the scientific validity of the test. Whether a series of tests would better define the Child-Pugh Class A patient who is also a relatively poor risk is not clear at present. Many investigations demonstrate the correlation of various assessment tools with each other, yet nothing distinguishes them in predicting risk beyond what is learned from the CP score. In a group of CP Class A patients, the extent of the disease, the nature of underlying cirrhosis, and the extent of resection provide the clinical backdrop against which a decision for resection must be made. It may well be that one test may not do it, or that one single assessment of the ICG or the 15-minute receptor volume of GSA may be inadequate to project the nuances of liver function. Thus, 99m-Tc GSA scintigraphy will provide volumetric receptor data, as well as kinetic distribution curves, and may prove a useful test in the future. Whether GSA is ultimately to be proven useful requires a correlation of the test with actual clinical outcomes, rather than correlation with other tests or with the CP score. Discovering which patients are the poor risk Child Class A patients is the desired goal. To have value, the GSA scan must augment, not mimic, the CP score. In view of the fact that experienced surgeons appear to be astute in their ability to select patients for hepatic resection, finding a more refined test will require large numbers of patients at several centers to correlate the test results and the outcomes against the spectrum of postoperative liver failure, including death. It appears that one lesson learned from portal vein embolization is that functional liver volume can be preserved. The compensatory hyperplasia that occurs in the contralateral hepatic lobe demonstrates two important features: (1) function of the opposite lobe has been transferred when evaluated by 99m-Tc-GSA, and (2) one considerable metabolic drain on the postoperative recovery from hepatic resection (ie, liver regeneration) can be attended to before the surgery. Cirrhotic livers do regenerate, but more slowly. Thus, pregrowing the remnant section of liver eliminates one stress on liver reserves following liver resection. For hepatocellular carcinoma or metastasis in cirrhotic patients, portal vein occlusion may be the best way to improve hepatic functional reserve. ICG retention may not corroborate return-to-baseline hepatic function within 2 weeks of portal vein occlusion,but may demonstrate a return to baseline when studied 6 to 8 weeks following the procedure. 99m-Tc-GSA is presently the best means to document compensatory hyperplasia and, possibly, a shift of functional reserve to the planned remnant of a more than four-segment hepatic resection. Whether this will predict the safe outcome of resection remains to be seen.

Estimation of fractional liver uptake and blood retention of 99mTc-DTPA-galactosyl human serum albumin: an application of a simple graphical method to dynamic SPECT

The objective of this study was to investigate clinical utility of a graphical method for estimating liver uptake and blood retention of 99mTc-DTPA-galactosyl human serum albumin (99mTc-GSA; DTPA is diethylenetriaminepentaacetic acid) using dynamic single photon emission computed tomography (SPECT) data. When considering the kinetics of 99mTc-GSA, if it is assumed that (1) 99mTc-GSA distributes only between blood and liver, and (2) no metabolism of 99mTc-GSA occurs during the observation period, a plot of liver counts versus cardiac blood pool counts should, theoretically, be a straight line. From the slope and y intercept of a regression line, coefficients for converting count based liver and blood pool data to the per cent injected dose (%ID) can be calculated. The applicability of this method was tested on dynamic SPECT data from 30 patients with liver dysfunction. To validate this method, plasma concentrations (%ID/ml plasma) at 6, 15 and 30 min after the injection were estimated by this method and compared with the measured ones. To investigate the clinical significance of the per cent liver uptake, the value obtained by this method was compared with the results of conventional liver function tests, including serum albumin, the hepaplastin test, prothrombin time and indocyanine green clearance. In every data set, a plot of liver counts to cardiac blood pool counts was fitted well by a straight line (P<0.00001). Estimated plasma concentrations by this method showed good correlation with the measured ones at 6, 15 and 30 min after the injection (r=0.748, 0.838, 0.875, respectively; P<0.0001). The liver uptake determined by this method showed good correlation with the results of conventional hepatic function tests (P<0.002). The graphical method could provide an accurate estimate of %ID of 99mTc-GSA in blood without the need for blood sampling. The liver uptake determined by this method could be a simple but useful quantitative indicator of hepatic function.

Analysis of liver single photon emission computed tomography in a case of fulminant hepatic failure

Fulminant hepatic failure is associated with a high mortality rate. Thus, accurate assessment of hepatic functional reserve and hepatic regeneration is important. We describe a 67-year-old woman who survived subacute hepatic failure. We had an opportunity to monitor the clinical course of the patient using single photon emission computed tomography (SPECT) with 99mTc-galactosyl-human serum albumin (99mTc-GSA) and frequent hematological examinations. On admission, prothrombin time was remarkably prolonged (23.1% of control). The liver uptake of 99mTc-GSA was also considerably low. She responded well to treatment. Four weeks after admission, SPECT analysis showed a dramatic increase in liver uptake of 99mTc-GSA, suggesting promotion of hepatic regeneration. Moreover, functional liver volume calculated from the SPECT data showed a marked increase at 4 weeks after admission, whereas CT scan showed no change at that point. This indicated that SPECT with 99mTc-GSA reflected functional hepatocytes more accurately than liver volume determined by CT scan, which cannot exclude nonfunctional hepatocytes. The patient's condition improved in parallel with the improvements in the indices measured by SPECT and hematological examinations. SPECT analysis is practically useful for the prompt assessment of improvement in patients with fulminant hepatic failure.

Simple scintigraphic parameters with Tc-99m galactosyl human serum albumin for clinical staging of chronic hepatocellular dysfunction

Technetium-99m labeled diethylenetriaminepentaacetic acid (DTPA)-galactosyl human serum albumin (GSA) has been used for hepatocellular functional evaluation. This study proposed new and simple parameters to overcome the limitations of conventional parameters, and they were applied to the clinical staging of chronic liver dysfunction. The study group consisted of 93 patients including 81 with liver dysfunction and 12 control patients. In addition to the two conventional parameters, namely, receptor index (LHL15 = liver count divided by the sum of liver and heart counts at 15 minutes) and clearance index (HH15 = heart count at 15 minutes divided by the heart count at 3 minutes), 6 new parameters for Tc-99m GSA uptake and clearance were generated. The conventional receptor index of LHL15 showed a large variation depending on the size of region of interest (ROI) over the heart. The LHL15 normalized by the ROI size (nLHL15) showed more stable data and a better separation of mild liver dysfunction. A hyperbolic relationship between the LHL15 and HH 15 changed to a linear relationship by using the nLHL15 index. The combination of the liver to heart average count ratio at 15 minutes (LH 15) and T-half (minute) of the heart count also could differentiate each stage well. In conclusion, the use of the ROI-area normalized nLHL is recommended instead of the conventional LHL15. The indices of LH15 and T-half could be alternatively used as practical parameters for clinical staging in liver function.

Imaging of intraperitoneal tumors with technetium-99m GSA

99mTc labeled galactosyl serum albumin (GSA) has been used clinically as a receptor-binding agent for the assessment of liver function. The aim of this study was to investigate the usefulness of 99mTc-GSA in intraperitoneal (i.p.) tumor imaging. A tumor model was established by i.p. inoculating nude mice with human ovarian cancer cell SHIN-3, or colon cancer cell LS 180. Radiolabels were i.p. injected into the tumor-bearing mice and the biodistribution of radioactivity was examined. After administration, 99mTc-GSA rapidly accumulated in the tumor. The tumor uptake was 5.82-8.46 %ID/g from 30 min to 6 h after the injection. Radioactivity in the blood was very low, less than 0.3 %ID/g, resulting in high tumor-to-blood ratio. Tumors could be clearly seen by scintigraphic imaging. Accumulation of i.p.-injected 99mTc labeled human serum albumin (HSA) in i.p. tumors was similar to that of 99mTc-GSA, but radioactivity of 99mTc-HSA in the circulation was high, resulting in a significantly lower tumor-to-blood ratio. In conclusion, 99mTc-GSA, when i.p. injected, accumulated in i.p. tumors and cleared from circulation rapidly, which would make it useful for the imaging of i.p. tumors.