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

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 .

99mTc-GSA scintigraphy for assessing the functional volume ratio of the future liver remnant in the routine practice of liver resection

Background

The significance of incorporating regional functional heterogeneity assessment by liver scintigraphy into the calculation of the future liver remnant has been reported. However, liver scintigraphy entails additional costs and radiation exposure. Nevertheless, studies describing when liver scintigraphy demonstrates an actual benefit over computed tomography liver volumetry are lacking. Thus, we evaluated the degree of agreement between future liver remnant % values calculated by technetium ^99mTc diethylenetriaminepentaacetic acid-galactosyl human serum albumin scintigraphy (galactosyl human serum albumin–based future liver remnant %) and those by computed tomography volumetry and investigated the practical impact of performing regional functional heterogeneity assessment.

Methods

The Bland–Altman method was used to retrospectively analyze the agreement between computed tomography– and galactosyl human serum albumin–based future liver remnant % measurements in 84 patients.

Results

In ordinary patients with a computed tomography–based future liver remnant % greater than 50%, there was a good agreement between both measurements. However, in cases with a computed tomography–based future liver remnant % less than 40%, galactosyl human serum albumin–based measurements were significantly smaller than computed tomography–based values, with 88% of these patients exhibiting a galactosyl human serum albumin–based future liver remnant % less than 30%. After portal vein embolization, galactosyl human serum albumin–based measurements were primarily greater than or in agreement with computed tomography–based values, even in cases with a computed tomography–based future liver remnant % less than 40%.

Conclusion

Adding ^99mTc diethylenetriaminepentaacetic acid-galactosyl human serum albumin scintigraphy to computed tomography liver volumetry is advised when deciding on hepatectomy in patients with a computed tomography–based future liver remnant % less than 50%. If the computed tomography–based future liver remnant % is smaller than 40%, it is strongly recommended to check future liver remnant % by ^99mTc diethylenetriaminepentaacetic acid-galactosyl human serum albumin scintigraphy. In other cases, computed tomography–based future liver remnant % calculation alone can be regarded as the gold standard of safe hepatectomy.

The impact of elastography with virtual touch quantification of future remnant liver before major hepatectomy

Background

Liver elastography with virtual touch quantification (VTQ) measures the velocity of the shear wave generated by a short-duration acoustic force impulse, with values expressed in units of velocity (m/s). VTQ can evaluate right or left hepatic lobes separately. VTQ might be appropriate for the evaluation of future remnant liver after hepatectomy.

Methods

We analyzed 95 patients underwent liver elastography with VTQ and both future remnant liver and resected side before hepatectomy of more than two sections, except for central bisectionectomy. We divided the patients into a high VTQ group (≥1.52 m/s, n=37, 39%) and a low VTQ group (<1.52 m/s, n=58, 61%) according to the VTQ of future remnant liver. Transient elastography could not be performed in 22 cases due to tumor size. We defined the group with liver stiffness measurement (LSM) ≥7.9 kPa as the high LSM group (n=29, 40%) and those with LSM <7.9 kPa as the low LSM group (n=44, 60%). We investigated the outcome after hepatectomy and the correlations between the VTQ of future remnant liver and other indicators for hepatic fibrosis.

Results

The high VTQ group showed significantly higher postoperative ascites (19% vs. 3%; P=0.01), pathological fibrosis (19% vs. 5%; P=0.03), and rates of patients with postoperative T-bil ≥2.0 mg/dL (70% vs. 40%; P<0.01). The high LSM group showed no significant postoperative outcomes compared to the low LSM group. The high VTQ group showed a higher frequency of male gender (78% vs. 57%; P=0.03), higher indocyanine green retention rate at 15 min (ICGR15) (10.5% vs. 6.3%; P<0.01), hyaluronic acid (100 vs. 67 ng/mL; P=0.02), type IV collagen 7S (7.6 vs. 5.1 ng/mL; P<0.01), Mac-2 binding protein glycan isomer (M2BPGi) (1.19 vs. 1.00; P=0.01), Fibrosis-4 (FIB-4) index (2.25 vs. 1.76; P=0.01), and aspartate aminotransferase to platelet ratio index (APRI) score (0.64 vs. 0.41; P<0.01). We also observed an especially strong positive correlation between the high VTQ and hyaluronic acid or type IV collagen 7S.

Conclusions

Elastography with VTQ for future remnant liver before major hepatectomy is an accurate and useful method as a preoperative evaluation.

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.

Evaluation of Liver Function and the Role of Biliary Drainage before Major Hepatic Resections

Background

Prevention of posthepatectomy liver failure is a prerequisite for improving the postoperative outcome of perihilar cholangiocarcinoma. From this perspective, appropriate assessment of future liver remnant (FLR) function and the optimized preparation are mandatory.

Summary

FLR volume ratio using CT volumetry based on 3-dimensional vascular imaging is the current assessment yardstick and is sufficient for assessing a normal liver. However, in a liver with underling parenchymal disease such as fibrosis or prolonged jaundice, weighing up the degree of liver damage against the FLR volume ratio is necessary to know the real FLR function. For this purpose, the indocyanine green (ICG) clearance test, monoethylglycinexylidide (MEGX) test, liver maximum capacity (LiMAX) test, ^99mTc-labeled galactosyl human serum albumin (^99mTc-GSA) scintigraphy, albumin-bilirubin (ALBI) grade, and ALPlat (albumin × platelets) criterion are used. After the optimization of FLR function by means of portal vein embolization or associating liver partition and PVL (portal vein ligation) for staged hepatectomy (ALPPS), SPECT scintigraphy with either ^99mTc-GSA or ^99mTc-mebrofenin compensates for misestimation due to the regional heterogeneity of liver function. The role of preoperative biliary drainage has long been debated, with the associated complications having led to a lack of approval. However, the recent establishment of safety and an improvement in success rates of endoscopic biliary drainage seem to be changing the awareness of the importance of biliary drainage.

Key Messages

Appropriate selection of an assessment method is of prime importance to predict the FLR function according to the preoperative condition of the liver. Preoperative biliary drainage in patients with perihilar cholangiocarcinoma is gaining support due to the increasing safety and success rate, especially in patients who need optimization of their liver function before hepatectomy.

99m-Technetium galactosyl human serum albumin scanning to evaluate liver function after stereotactic body radiotherapy for hepatocellular carcinoma: A case report

The primary choice among treatment options for liver malignancies is surgery. However, if surgery cannot be performed, Stereotactic body radiotherapy (SBRT) may be effective. 99m-technetium galactosyl human serum albumin (GSA) single-photon emission computed tomography (SPECT) imaging is useful for the assessment of liver function before surgery. We report the case of a 77-year-old man who had undergone SBRT for hepatocellular carcinoma of the left lobe of the liver 2 years previously. Follow-up revealed a 15-mm hepatocellular carcinoma at the edge of the right lobe of the liver. 99m-technetium GSA SPECT was performed before SBRT to confirm that there was no accumulation in the left lobe and to ensure that there was good function of the right lobe. Three months after SBRT, the tumor had responded, and decreases in GSA accumulation were observed in line with the radiation beam. Because hepatocellular carcinoma often relapses, it is important to assess the anatomic site of liver dysfunction before and after radiation. This case demonstrates that 99m-technetium GSA SPECT is useful for this purpose.

Heterogeneous liver uptake of Tc-99m-GSA as quantified through SPECT/CT helps to evaluate the degree of liver fibrosis: A retrospective observational study

Tc-99m-galactosyl human serum albumin (GSA) scintigraphy is used to assess the hepatic functional reserve, and allows for visual assessment of the residual hepatocyte distribution on single-photon emission computed tomography/computed tomography (SPECT/CT) images. The association between heterogeneous liver uptake of Tc-99m-GSA and liver fibrosis remains to be studied in detail. We analyzed this association.Fifty-one patients with chronic hepatobiliary disease undergoing a Tc-99m-GSA scintigraphy were included in this study. The receptor (LHL15) and blood clearance (HH15) indexes (the uptake ratios of the liver and heart) were obtained from dynamic planar images. The liver uptake count maximum-to-mean ratio (LUC Max/Mean) was calculated from single-photon emission computed tomography/computed tomography (SPECT/CT) images as an indicator of the Tc-99m-GSA liver uptake heterogeneity. We assessed the relationship between these quantified values and liver fibrosis.There were 30 Child-Pugh classification grade A patients, 16 grade B patients, and 5 grade C patients. Among the 30 patients whose liver histopathology was evaluable, those with advanced liver fibrosis (F2-4) had a lower LHL15 than those with mild liver fibrosis (F0-1) (median, 0.90 vs. 0.92, P = .04), and a higher LUC Max/Mean (median, 1.80 vs. 1.70, P = .02). The multivariate analysis identified platelets (P = .04) and the LUC Max/Mean (P = .04) as contributing factors of advanced liver fibrosis.These findings suggest that Tc-99m-GSA SPECT/CT can be used not only to assess the hepatic functional reserve, but also to evaluate a degree of liver fibrosis.

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.