Quantitative liver-spleen scan using single photon emission computerized tomography (SPECT) for assessment of hepatic function in cirrhotic patients

Current Insights into Molecular Mechanisms and Potential Biomarkers for Treating Radiation-Induced Liver Damage

Highly conformal delivery of radiation therapy (RT) has revolutionized the treatment landscape for primary and metastatic liver cancers, yet concerns persist regarding radiation-induced liver disease (RILD). Despite advancements, RILD remains a major dose-limiting factor due to the potential damage to normal liver tissues by therapeutic radiation. The toxicity to normal liver tissues is associated with a multitude of physiological and pathological consequences. RILD unfolds as multifaceted processes, intricately linking various responses, such as DNA damage, oxidative stress, inflammation, cellular senescence, fibrosis, and immune reactions, through multiple signaling pathways. The DNA damage caused by ionizing radiation (IR) is a major contributor to the pathogenesis of RILD. Moreover, current treatment options for RILD are limited, with no established biomarker for early detection. RILD diagnosis often occurs at advanced stages, highlighting the critical need for early biomarkers to adjust treatment strategies and prevent liver failure. This review provides an outline of the diverse molecular and cellular mechanisms responsible for the development of RILD and points out all of the available biomarkers for early detection with the aim of helping clinicians decide on advance treatment strategies from a single literature recourse.

Liver injury and recovery following radiation therapy for hepatocellular carcinoma: insights from functional liver imaging

Aim

A critical need for hepatocellular carcinoma (HCC) management is understanding how the liver recovers following radiotherapy (RT). We hypothesized that functional liver imaging with 99mTc-sulfur colloid (SC) SPECT/CT provides additional information on liver injury and recovery after RT compared to conventional imaging.

Methods

The liver function of patients with HCC was assessed using 99mTc-SC SPECT/CT imaging before and after definitive RT. The anatomical liver volume (ALV) was segmented on CT imaging. Liver function was measured as the total liver function (TLF) encompassing 30% of maximum SC uptake. Changes in ALV and TLF were compared to clinical characteristics.

Results

Of 31 patients with evaluable post-RT SC SPECT/CT scans (total of 32), 23 had pre-treatment Child-Pugh (CP)-A and 9 had CP-B/C scores. The median follow-up post-RT was 57 days. The median change in ALV was -1.7% with no significant difference between CP-A and CP-B/C patients (P = 0.26) or between short- (32-99 days) and long-term (271-1120 days) follow-up imaging groups (P = 0.28). The median change in TLF post-RT was -24% and was significantly different between short- and long-term groups (-39% vs. 2%, P = 0.001) and between CP-A and CP-B/C patients (-19% vs. -57%, P = 0.002). TLF significantly decreased following treatment at all radiation dose levels, with the decline correlating with the dose (P < 0.001).

Conclusion

Functional imaging provides additional information regarding liver injury and recovery following RT that conventional imaging cannot reveal. Patients with CP-A liver status showed less decline following RT and most had liver function near or above pre-treatment levels.

Phase I trial of single-photon emission computed tomography-guided liver-directed radiotherapy for patients with low functional liver volume

BACKGROUND

Traditional constraints specify that 700 cc of liver should be spared a hepatotoxic dose when delivering liver-directed radiotherapy to reduce the risk of inducing liver failure. We investigated the role of single-photon emission computed tomography (SPECT) to identify and preferentially avoid functional liver during liver-directed radiation treatment planning in patients with preserved liver function but limited functional liver volume after receiving prior hepatotoxic chemotherapy or surgical resection.

METHODS

This phase I trial with a 3 + 3 design evaluated the safety of liver-directed radiotherapy using escalating functional liver radiation dose constraints in patients with liver metastases. Dose-limiting toxicities were assessed 6-8 weeks and 6 months after completing radiotherapy.

RESULTS

All 12 patients had colorectal liver metastases and received prior hepatotoxic chemotherapy; 8 patients underwent prior liver resection. Median computed tomography anatomical nontumor liver volume was 1584 cc (range = 764-2699 cc). Median SPECT functional liver volume was 1117 cc (range = 570-1928 cc). Median nontarget computed tomography and SPECT liver volumes below the volumetric dose constraint were 997 cc (range = 544-1576 cc) and 684 cc (range = 429-1244 cc), respectively. The prescription dose was 67.5-75 Gy in 15 fractions or 75-100 Gy in 25 fractions. No dose-limiting toxicities were observed during follow-up. One-year in-field control was 57%. One-year overall survival was 73%.

CONCLUSION

Liver-directed radiotherapy can be safely delivered to high doses when incorporating functional SPECT into the radiation treatment planning process, which may enable sparing of lower volumes of liver than traditionally accepted in patients with preserved liver function.

TRIAL REGISTRATION

NCT02626312.

Stereotactic Body Radiation Therapy (SBRT) for Hepatocellular Carcinoma (HCC) With Single Photon Emission Computed Tomography (SPECT) Functional Treatment Planning in Patients With Advanced Hepatic Cirrhosis

Purpose

We report on the feasibility and outcomes of liver stereotactic body radiation therapy (SBRT) for hepatocellular carcinoma (HCC) with single-photon emission computed tomography (SPECT) functional treatment planning in patients with Child-Pugh (CP) B/C cirrhosis.

Methods and Materials

Liver SPECT with 99mTc-sulfur colloid was coregistered to treatment planning computed tomography (CT) for the guided avoidance of functional hepatic parenchyma during SBRT. Functional liver volumes (FLVs) obtained from SPECT were compared with anatomic liver volumes defined on the planning CT. Radiation dose constraints were adapted exclusively to FLV. Local control, toxicity, and survival were reported with at least 6 months of radiographic follow-up. Pre- and posttransplant outcomes were analyzed in a subset of patients who completed SBRT as a bridge to liver transplant. Model of End-Stage Liver Disease was used to score hepatic function before and after SBRT completion.

Results

With a median follow-up of 32 months, 45 patients (58 lesions) with HCC and CP-B/C cirrhosis received SBRT to a median dose of 45 Gy (3-5 fractions). FLV loss (34%, P < .001) was observed in all patients, and the functional and anatomic liver volumes matched well in a control group of noncirrhotic/non-HCC patients. Despite marked functional parenchyma retraction, the amount of FLV on SPECT exposed to the threshold irradiation was significantly less than the CT liver volumes (P < .001) because of the optimized beam placement during dosimetry planning. Twenty-three patients (51%) successfully completed orthotopic liver transplant, with a median time to transplant of 9.2 months. With 91% in-field local control, the overall 2-year survival was 65% (90% after the orthotopic liver transplant), with no incidence of radiation-induced liver disease observed within 3 to 4 months or accelerated CP class migration from B to C within the first 6 months post-SBRT. Mean Model of End-Stage Liver Disease-Na score was not significantly elevated at 3-month intervals after SBRT completion.

Conclusions

Functional treatment planning with 99mTc sulfur colloid SPECT/CT allows identification and avoidance of functional hepatic parenchyma in patients with CP-B/C cirrhosis, leading to low toxicity and satisfactory transplant outcomes.

Quantitative liver SPECT/CT is a novel tool to assess liver function, prognosis, and response to treatment in cirrhosis

Background

Functional liver reserve is an important determinant of survival in cirrhosis. The traditional indocyanine green test (ICG) is cumbersome. Hence, we developed and validated a novel liver imaging, a hybrid of SPECT and CT (Q-SPECT/CT), for evaluating disease severity, outcomes, and response to treatment in decompensated cirrhosis (DC).

Methods

We recruited a cohort of DC patients at a tertiary institute between 2016-2019. First, we standardized the Q-SPECT/CT across a predefined range of volumes through phantom experiments. Then we performed clinical and laboratory evaluations, ICG test (retention at 15 min), and Q-SPECT/CT at baseline and 12 months of granulocyte colony-stimulating factor (G-CSF) and standard medical treatment (SMT).

Results

In 109 DC patients, 87.1% males, aged 51 ± 10 years, MELD: 14 (7-21), the percent quantitative liver uptake (%QLU) on Q-SPECT/CT exhibited a strong correlation with CTP (r = -0.728, p < 0.001), MELD (r = -0.743; p < 0.001) and ICG-R-15 (r = -0.720, p < 0.001) at baseline. %QLU had the maximum discrimination (AUC: 0.890-0.920), sensitivity (88.9-90.3%), specificity (81.2-90.7%), and accuracy (85.8-89.4%) than liver volumes on Q-SPECT/CT or ICG test for classifying patients in CTP/MELD based prognostic categories. A significant increase in %QLU (26.09 ± 10.06 to 31.2 ± 12.19, p = 0.001) and improvement in CTP/MELD correlated with better survival of G-CSF treated DC patients (p < 0.05). SMT did not show any improvement in Q-SPECT/CT or clinical severity scores (p > 0.05). %QLU > 25 (adj.H.R.: 0.234, p = 0.003) and G-CSF treatment (adj.H.R.: 0.414, p = 0.009) were independent predictors of better 12-months survival in DC.

Conclusion

Q-SPECT/CT (%QLU) is a novel non-invasive, diagnostic, prognostic, and theragnostic marker of liver reserve and its functions in cirrhosis patients.

Clinical trial registration

Clinicaltrials.gov, NCT02451033 and NCT03415698.

Programmed Death Ligand 1 Is Overexpressed in Liver Macrophages in Chronic Liver Diseases, and Its Blockade Improves the Antibacterial Activity Against Infections

BACKGROUND AND AIMS

Bacterial infections are common and severe in cirrhosis, but their pathogenesis is poorly understood. Dysfunction of liver macrophages may play a role, but information about their function in cirrhosis is limited. Our aims were to investigate the specific profile and function of liver macrophages in cirrhosis and their contribution to infections. Macrophages from human cirrhotic livers were characterized phenotypically by transcriptome analysis and flow cytometry; function was assessed in vivo by single photon emission computerized tomography in patients with cirrhosis. Serum levels of specific proteins and expression in peripheral monocytes were determined by ELISA and flow cytometry. In vivo phagocytic activity of liver macrophages was measured by spinning disk intravital microscopy in a mouse model of chronic liver injury.

APPROACH AND RESULTS

Liver macrophages from patients with cirrhosis overexpressed proteins related to immune exhaustion, such as programmed death ligand 1 (PD-L1), macrophage receptor with collagenous structure (MARCO), and CD163. In vivo phagocytic activity of liver macrophages in patients with cirrhosis was markedly impaired. Monocytes from patients with cirrhosis showed overexpression of PD-L1 that paralleled disease severity, correlated with its serum levels, and was associated with increased risk of infections. Blockade of PD-L1 with anti-PD-L1 antibody caused a shift in macrophage phenotype toward a less immunosuppressive profile, restored liver macrophage in vivo phagocytic activity, and reduced bacterial dissemination.

CONCLUSION

Liver cirrhosis is characterized by a remarkable impairment of phagocytic function of macrophages associated with an immunosuppressive transcriptome profile. The programmed cell death receptor 1/PD-L1 axis plays a major role in the impaired activity of liver macrophages. PD-L1 blockade reverses the immune suppressive profile and increases antimicrobial activity of liver macrophages in cirrhosis.

Non-Invasive Targeted Hepatic Irradiation and SPECT/CT Functional Imaging to Study Radiation-Induced Liver Damage in Small Animal Models

Radiation therapy (RT) has traditionally not been widely used in the management of hepatic malignancies for fear of toxicity in the form of radiation-induced liver disease (RILD). Pre-clinical hepatic irradiation models can provide clinicians with better understanding of the radiation tolerance of the liver, which in turn may lead to the development of more effective cancer treatments. Previous models of hepatic irradiation are limited by either invasive laparotomy procedures, or the need to irradiate the whole or large parts of the liver using external skin markers. In the setting of modern-day radiation oncology, a truly translational animal model would require the ability to deliver RT to specific parts of the liver, through non-invasive image guidance methods. To this end, we developed a targeted hepatic irradiation model on the Small Animal Radiation Research Platform (SARRP) using contrast-enhanced cone-beam computed tomography image guidance. Using this model, we showed evidence of the early development of region-specific RILD through functional single photon emission computed tomography (SPECT) imaging.

Spleno-hepatic index to predict portal hypertension by equilibrium radionuclide ventriculography

BACKGROUND

Structural and morphological changes accompanying liver cirrhosis lead to portal hypertension (PHT), which is the first step of most of the complications in patients with liver cirrhosis. Therefore, the development of noninvasive techniques to detect PHT is crucial for prognosis and treatment.

AIM

The aim of our study was to assess the diagnostic performance of a new spleno-hepatic index (SHI) measured from equilibrium radionuclide ventriculography (ERV) images in detecting patients with cirrhotic PHT.

METHODS AND RESULTS

A total of 38 patients with PHT were compared with 30 controls without liver disease. The SHI was measured on the sum of the tomographic images from the ERV and calculated according to the following formula: SHI=(mean splenic count×longest hepatic length)/mean hepatic count. Mean SHI was 54±14 and 36±8 (P<0.001) among patients with PHT and controls, respectively. A cutoff value of 40 for the SHI allowed a sensitivity of 90% and specificity of 77% to detect PHT. SHI greater than 51 was 100% specific. In a subset of 25 patients, SHI was not correlated with hepatic venous pressure gradient measured invasively in the right hepatic vein (R=-0.08, P=0.70).

CONCLUSION

Quantification of SHI derived from ERV could be used to detect liver cirrhosis with PHT although it is not linearly correlated with the hepatic venous pressure gradient. SHI should be considered as a useful index for the identification of PHT in patients referred for the detection/exploration of cirrhotic cardiomyopathy by ERV.

Functional liver image guided hepatic therapy (FLIGHT) with hepatobiliary iminodiacetic acid (HIDA) scans

PURPOSE

Hepatobiliary iminodiacetic acid (HIDA) scans provide global and regional assessments of liver function that can serve as a road map for functional avoidance in stereotactic body radiation therapy (SBRT) planning. Functional liver image guided hepatic therapy (FLIGHT), an innovative planning technique, is described and compared with standard planning using functional dose-volume histograms. Thresholds predicting for decompensation during follow up are evaluated.

METHODS AND MATERIALS

We studied 17 patients who underwent HIDA scans before SBRT. All SBRT cases were replanned using FLIGHT. The following dosimetric endpoints were compared for FLIGHT versus standard SBRT planning: functional residual capacity <15 Gy (FRC₁₅HIDA), mean liver dose (MLD), equivalent uniform dose (EUD), and functional EUD (FEUD). Receiver operating characteristics curves were used to evaluate whether baseline HIDA values, standard cirrhosis scoring, and/or dosimetric data predicted clinical decompensation.

RESULTS

Compared with standard planning, FLIGHT significantly improved FRC₁₅HIDA (mean improvement: 5.3%) as well as MLD, EUD, and FEUD (P < .05). Considerable interindividual variations in the extent of benefit were noted. Decompensation during follow-up was associated with baseline global HIDA <2.915%/min/m², FRC₁₅HIDA <2.11%/min/m², and MELD ≥11 (P < .05).

CONCLUSIONS

FLIGHT with HIDA-based parameters may complement blood chemistry-based assessments of liver function and facilitate individualized, adaptive liver SBRT planning.

Assessment of functional liver reserve: old and new in 99mTc-sulfur colloid scintigraphy

PURPOSE

A semiquantitative assessment of hepatic reticuloendothelial system function using colloidal particles scintigraphy has been proposed previously as a surrogate for liver function evaluation. In this article, we present an updated method for the overall assessment of technetium-99m (Tc)-sulfur colloid (SC) biodistribution that combines information from planar and attenuation-corrected Tc-SC single-photon emission computed tomography (SPECT) images. The imaging protocol described here was developed as an easy-to-implement method to assess overall and regional liver function changes associated with chronic liver disease.

PATIENTS AND METHODS

Thirty patients with chronic liver disease and primary liver cancers underwent Tc-SC whole-body planar imaging and upper-abdomen SPECT/computed tomography (CT) imaging before external beam radiation therapy. Liver plus spleen and bone marrow counts as a fraction of whole-body total counts were calculated from SC planar imaging. Attenuation correction Tc-SC images were rigidly coregistered with treatment planning CT images that contained liver and spleen regions-of-interest. Ratios of total liver counts to total spleen counts were obtained from the aligned Tc-SC SPECT and CT images, and were subsequently used to separate liver plus spleen counts obtained on the planar images. This hybrid SPECT/CT and planar scintigraphy approach yielded an updated estimation of whole-body SC distribution. These biodistribution estimates were compared with historical data for reference. Statistical associations of Tc-SC biodistribution to liver function parameters and liver disease scoring systems (Child-Pugh) were evaluated by Spearman rank correlation.

RESULTS

Percentages of Tc-SC uptake ranged from 19.3 to 77.3% for the liver; 3.4 to 40.7% for the spleen; and 19.0 to 56.7% for the bone marrow. Spearman's correlation coefficient showed a significant statistical association between Child-Pugh score and bone marrow uptake at 0.55 (P≤0.05), liver uptake at 0.71 (P≤0.001), spleen uptake at 0.56 (P≤0.05), and spleen plus bone marrow uptake at 0.71 (P≤0.001). There was also a good correlation of SC uptake percentages with individual quantitative liver function components such as albumin and total bilirubin, and qualitative liver function components (varices, portal hypertension, ascites). For albumin: r=0.64 (P<0.001) compared with liver uptake percentage from the whole-body counts, r=0.49 (P<0.001) compared with splenic uptake percentage, and r=0.45 (P≤0.05) compared with bone marrow uptake percentage.

CONCLUSION

We describe a novel liver function quantitative assessment method that combines whole-body planar images and SPECT/CT attenuation-corrected images of Tc-SC distribution. Attenuation-corrected SC images provide valuable regional liver function information, which is a unique feature compared with other imaging methods available. The results of our study indicate that the Tc-SC uptake by the liver, spleen, and bone marrow correlates with liver function parameters in patients with diffuse liver disease and the correlation with liver disease severity is slightly better for liver uptake percentages than for individual values of bone marrow and spleen uptake percentages.

Measuring total liver function on sulfur colloid SPECT/CT for improved risk stratification and outcome prediction of hepatocellular carcinoma patients

Background

Assessment of liver function is critical in hepatocellular carcinoma (HCC) patient management. We evaluated parameters of [^99mTc] sulfur colloid (SC) SPECT/CT liver uptake for association with clinical measures of liver function and outcome in HCC patients.

Methods

Thirty patients with HCC and variable Child-Turcotte-Pugh scores (CTP A5-C10) underwent [^99mTc]SC SPECT/CT scans for radiotherapy planning. Gross tumor volume (GTV), anatomic liver volume (ALV), and spleen were contoured on CT. SC SPECT image parameters include threshold-based functional liver volumes (FLV) relative to ALV, mean liver-to-spleen uptake ratio (L/S_mean), and total liver function (TLF) ratio derived from the product of FLV and L/S_mean. Optimal SC uptake thresholds were determined by ROC analysis for maximizing CTP classification accuracy. Image metrics were tested for rank correlation to composite scores and clinical liver function parameters. Image parameters of liver function were tested for association to overall survival with Cox proportional hazard regression.

Results

Optimized thresholds on SC SPECT were 58 % of maximum uptake for FLV, 38 % for L/S_mean, and 58 % for TLF. TLF produced the highest CTP classification accuracy (AUC = 0.93) at threshold of 0.35 (sensitivity = 0.88, specificity = 0.86). Higher TLF was associated with lower CTP score: TLF_A = 0.6 (0.4–0.8) versus TLF_B = 0.2 (0.1–0.3), p < 10⁻⁴. TLF was rank correlated to albumin and bilirubin (|R| > 0.63). Only TLF >0.30 was independently associated with overall survival when adjusting for CTP class (HR = 0.12, 95 % CI = 0.02–0.58, p = 0.008).

Conclusions

SC SPECT/CT liver uptake correlated with differential liver function. TLF was associated with improved overall survival and may aid in personalized oncologic management of HCC patients.

Solutions that enable ablative radiotherapy for large liver tumors: Fractionated dose painting, simultaneous integrated protection, motion management, and computed tomography image guidance

The emergence and success of stereotactic body radiation therapy (SBRT) for the treatment of lung cancer have led to its rapid adoption for liver cancers. SBRT can achieve excellent results for small liver tumors. However, the vast majority of physicians interpret SBRT as meaning doses of radiation (range, 4-20 Gray [Gy]) that may not be ablative but are delivered within about 1 week (ie, in 3-6 fractions). Adherence to this approach has limited the effectiveness of SBRT for large liver tumors (>7 cm) because of the need to reduce doses to meet organ constraints. The prognosis for patients who present with large liver tumors is poor, with a median survival ≤12 months, and most of these patients die from tumor-related liver failure. Herein, the authors present a comprehensive solution to achieve ablative SBRT doses for patients with large liver tumors by using a combination of classic, modern, and novel concepts of radiotherapy: fractionation, dose painting, motion management, image guidance, and simultaneous integrated protection. The authors discuss these concepts in the context of large, inoperable liver tumors and review how this approach can substantially prolong survival for patients, most of whom otherwise have a very poor prognosis and few effective treatment options. Cancer 2016;122:1974-86. © 2016 American Cancer Society.

Functional imaging of radiation liver injury in a liver metastasis patient: imaging and pathologic correlation

BACKGROUND

Radiation therapy (RT) is increasingly being utilized as a treatment modality for the treatment of primary and metastatic liver malignancies. Accurate assessment of liver function and prediction of radiation induced liver disease (RILD) remains a challenge with conventional laboratory tests and imaging. Imaging-pathology correlation of hepatic injury after RT has been described with computer tomography (CT) imaging that depicts perfusion changes. However, these imaging changes may not directly characterize the functional capacity of the liver.

CASE PRESENTATION

This case report describes a patient that received preoperative chemoradiation and surgical resection for a liver metastasis from endometrial cancer. Sulfur colloid (SC) single photon emission computed tomography (SPECT/CT) was obtained post-chemoradiation and prior to surgery. Imaging-pathology correlation between radiation changes depicted on functional imaging using SC SPECT/CT and corresponding histopathology is described.

DISCUSSION

Quantitative SC SPECT/CT may allow non-invasive assessment of global and spatial liver function before treatment and enable personalized treatment approaches for liver-directed therapies.

Differential hepatic avoidance radiation therapy: Proof of concept in hepatocellular carcinoma patients

PURPOSE

To evaluate the feasibility of a novel planning concept that differentially redistributes RT dose away from functional liver regions as defined by (99m)Tc-sulphur colloid (SC) uptake on patient SPECT/CT images.

MATERIALS AND METHODS

Ten HCC patients with different Child-Turcotte-Pugh scores (A5-B9) underwent SC SPECT/CT scans in treatment position prior to RT that were registered to planning CT scans. Proton pencil beam scanning (PBS) therapy plans were optimized to deliver 37.5-60.0Gy (RBE) over 5-15 fractions using single field uniform dose technique robust to range and setup uncertainty. Photon volumetrically modulated arc therapy (VMAT) plans were optimized to the same prescribed dose and minimum target coverage. For both treatment modalities, differential hepatic avoidance RT (DHART) plans were generated to decrease dose to functional liver volumes (FLV) defined by a range of thresholds relative to maximum SC uptake (43-90%) in the tumor-subtracted liver. Radiation dose was redistributed away from regions of increased SC uptake in each FLV by linearly scaling mean dose objectives during PBS or VMAT optimization. DHART planning feasibility was assessed by a significantly negative Spearman's rank correlation (RS) between dose difference and SC uptake. Patient, tumor, and treatment planning characteristics were tested for association to DHART planning feasibility using non-parametric Kruskal-Wallis ANOVA.

RESULTS

Compared to conventional plans, DHART plans achieved a 3% FLV dose reduction for every 10% SC uptake increase. DHART planning was feasible in the majority of patients with 60% of patients having RS<-0.5 (p<0.01, range -1.0 to 0.2) and was particularly effective in 30% of patients (RS<-0.9). Mean dose to FLV was reduced by up to 20% in these patients. Only fractionation regimen was associated with DHART planning feasibility: 15 fraction courses were more feasible than 5-6 fraction courses (RS<-0.93 vs. RS>-0.60, p<0.02).

CONCLUSION

Differential avoidance of functional liver regions defined on sulphur colloid SPECT/CT is achievable with either photon VMAT or proton PBS therapy. Further investigation with phantom studies and in a larger cohort of patients may validate the utility of DHART planning for HCC radiotherapy.

Hepatotoxicity and drug interactions in liver transplant candidates and recipients

In this article the medications that have been shown to increase rates of drug-induced liver injury in patients with cirrhosis and the important drug-drug interactions in recipients of liver transplantation are reviewed. In general, the risk of drug-induced liver injury in patients with cirrhosis does not seem to be higher when compared with the noncirrhotic population. There are, however, 2 classes of agents that have been implicated-medications used to treat tuberculosis and medications used to treat human immunodeficiency virus infection. However, with careful monitoring, even significant interactions can be effectively managed.

A prospective experimental study of liver fibrosis with ultrasound and its correlation with hepatic reserve function and hemodynamics

Background

Progressive hepatic fibrosis is the eventual cause of liver cirrhosis. Doppler ultrasound has been used to detect hemodynamic changes that are known to be present during the pre-cirrhotic stages of hepatic fibrogenesis. However, the relationship between the Doppler ultrasound parameters and the impairment of the liver function has not been fully investigated. The purpose of this study was to explore the hepatic function reserve and its relationship with the hepatic hemodynamics in a rabbit model of liver fibrosis using Doppler ultrasound.

Methods

A prospective study was performed. Sixty healthy New Zealand rabbits were included in this study. Eleven of them served as controls and were normally fed and provided with water drink; the rest of 49 rabbits that served as fibrosis group were normally fed but provided with 1.2 g/L of thioacetamide to create liver fibrosis model. Doppler measurements were performed in the portal trunk, proper hepatic artery and proper splenic artery. The hepatic circulation index (HCI) was calculated. Hepatic function reverse was evaluated by measuring the indocyanine green clearance and retention rate at 15 min (ICG R15) test. Portal venous pressure (PVP) was measured using the portal vein punctuation equipment.

Results

HCI was significantly decreased and PVP increased in the advanced fibrotic stage (F4) compared to mild and moderate fibrotic stage (F1-3), respectively (p<0.05). PVP and ICG R15 in the fibrotic group were significantly higher than that in the control group (ICG: 0.209±0.086 vs. 0.093±0.023, p<0.01). Within the fibrotic groups, PVP was higher in advanced fibrotic stage (F4) than those in mild (F1-2) or moderate (F3) fibrotic stages (p<0.05). Both HCI and PVP correlated well with ICG R15 (r = −0.890, and r = 0.780, p <0.01).

Conclusions

Hepatic function reserve closely relates to the hepatic hemodynamics in the rabbit model of liver fibrosis. Doppler Ultrasound could be reliably used to assess the hepatic function reserve and hemodynamic changes in different stages of liver fibrosis.

Demonstration of intrahepatic accumulated microbubble on ultrasound represents the grade of hepatic fibrosis

Objectives

To examine the feasibility of perflubutane-based ultrasound for grading hepatic fibrosis.

Methods

This prospective study included 202 subjects; main study (controls:33, F0–1:35, F2:26, F3:23, cirrhosis:29) and subsequent study (controls:16, F0–1:7, F2:20, F3:7, cirrhosis:6). Diagnostic abilities for assessing fibrosis grade were compared between contrast findings and FIB4 (age × AST/[platelet count × ALT^0.5]).

Results

High-power emission produced an intrahepatic band-like structure, and the three-layer appearance was less frequent and monolayer appearance was more frequent in cirrhosis than controls/chronic hepatitis (P < 0.0001). Intensity difference at 15-min phase showed most significant correlation with fibrosis grade (ρ = 0.79, P < 0.0001), and the best areas under the receiver operating characteristic curves are 0.88 for marked fibrosis, 0.95 for advanced fibrosis and 0.97 for cirrhosis, which were significantly higher than those of FIB4, 0.85 for marked fibrosis, 0.89 for advanced fibrosis and 0.90 for cirrhosis. Sensitivity, specificity and efficiency of the intensity difference were 88%, 72% and 81% for marked fibrosis, 85%, 91% and 89% for advanced fibrosis and 97%, 90% and 91% for cirrhosis, respectively. The subsequent study validated the main study results; significant correlation between the intensity difference and the fibrosis grade (ρ = 0.73–0.77, P < 0.0001).

Conclusions

Perflubutane-based ultrasound accurately predicts the grade of hepatic fibrosis.

Key Points

• The behaviour of intrahepatic microbubbles depends on the severity of hepatic fibrosis.

• Layer enhancement pattern simply represents the degree of chronic liver disease.

• Parenchymal intensity change due to high-power emission predicts the hepatic fibrosis grade.

THE ULTRASONIC THREE-DIMENSIONAL FILTER FOR THE QUANTITATIVE DIAGNOSIS OF LIVER FIBROSIS

At present, percutaneous liver biopsy is the gold standard in assessing liver fibrosis such as hepatitis and cirrhosis, but there could be sampling error, and specimens might not represent the state of the whole liver accurately because only about 0.002% of the organ is sampled. In this research, we propose the three-dimensional fiber structure extraction echo filter to realize a quantitative ultrasonic diagnosis. The filter is designed based on a statistical theory, and it is possible to reduce the noise contained in a back scattered ultrasonic echo signal, and to visualize the structure of a fiber.

Predicting liver failure following major hepatectomy

Pre-operative determination of the risk of liver dysfunction has come under criticism with regards to its usefulness in clinical practice. Opinion is split between centres which use such tests uniformly on all patients and those where clinical judgment alone is used. Published data would not suggest any difference in mortality, morbidity or liver failure rates between these groups. This review outlines and presents the evidence for pre-operative quantification of functional liver remnant volume.

The hospitalized patient with abnormal liver function tests

Evaluation of abnormal liver function tests (LFTs) in the hospitalized patient is typically more urgent than the outpatient setting. This process is best organized into four steps. The first step is to determine whether the abnormal LFTs are associated with the illness resulting in the admission to the hospital or preceded the present illness. The second is to determine the etiology of the underlying liver disease. The third step is to evaluate the severity of the liver dysfunction and determine if acute liver failure (ALF) or acute decompensation of chronic liver failure is present. The final step is to look for the presence of associated complications-either those of ALF or chronic liver failure as appropriate.

Improved hepatocyte function of future liver remnant of cirrhotic rats after portal vein ligation: a bonus other than volume shifting

BACKGROUND

Preoperative portal vein embolization is increasingly employed for those with hepatocellular carcinoma and cirrhosis to gain a volume-shifting effect. However, the alterations of histologic architecture and hepatocyte function of future liver remnant (FLR) remain unexplored.

METHODS

Portal vein ligation (PVL) was performed in cirrhotic and noncirrhotic rats. Regeneration indices that include the DNA synthesis index, restituted liver mass, and the redistributed volume ratio were measured. The indocyanine green 15' retention test (ICG-R15), histologic changes, total Knodell score, and activated hepatic stellate cells (HSCs) were measured before and after PVL. Tc-99m sulfur-colloid liver single photon emission computed tomography (SPECT) and diisopropyl iminoacetic acid (DISIDA) SPECT were conducted.

RESULTS

The redistributed volume ratio of cirrhotic rats was less than noncirrhotic rats (63% vs 80%, P < .01). The ICG-R15 of cirrhotic rats at day 7 after PVL was improved compared with baseline (6.0 +/- 4.1% vs 15.8 +/- 4.6%, P < .01). The total Knodell score and activated HSCs of FLR in cirrhotic rats both were decreased compared with those of baseline. The redistributed volume ratio of noncirrhotic and cirrhotic rats based on 99mTc sulfur-colloid SPECT were 79% and 64%, respectively. The clearance T(1/2) of FLR in cirrhotic rats based on DISIDA SPECT was decreased compared with baseline (5.2 +/- 1.9 min vs 8.6 +/- 3.1 min).

CONCLUSION

The regenerated functional liver mass of cirrhotic rats after PVL is less than noncirrhotic rats, whereas the hepatocyte function of FLR in cirrhotic rats is improved relevant to tissue remodeling.

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.

Correlation of liver-spleen scan findings with modified Child-Pugh classification

BACKGROUND

The Child-Pugh classification is used as an index of liver function. We assessed the relationship between modified Child score and sulfur colloid liver-spleen scintigraphy in histologically confirmed cirrhosis.

METHOD

Following injection of 185 MBq (99)mTechnetium-sulfur colloid, anterior and posterior images were obtained at 30 minutes with 500,000 counts. Liver-spleen scintigraphy pattern was divided visually into three categories: A (liver uptake >or= spleen uptake, without visualization of ribs and vertebrae), B (spleen uptake > liver uptake without visualization of ribs and vertebrae), and C (remarkable visualization of ribs and vertebrae).

RESULTS

Of 36 patients, 14 (38.8 %), 19 (58.8 %) and 3 (8.3 %) patients were categorized into Child-Pugh grades A, B and C, respectively, whereas 13 (36.1 %), 12 (33.3 %) and 11 (30.6 %) patients were categorized into scintigraphic grades A, B and C, respectively. In 14 patients the results of Child and scan classifications were in agreement, but in 22 patients the results were discordant. Kappa value was 0.072 (poor agreement).

CONCLUSION

There is no correlation between scintigraphic and Child-Pugh classifications. Scintigraphic classification may present a marker of body reactions to the disease, independent of Child-Pugh modified classification. Further studies are needed to determine which one of these classifications has better concordance with the patient's outcome.

Noninvasive evaluation of liver disease severity

In assessing the severity of chronic liver disease, one measures either the fibrotic structure of the liver or liver function. This article reviews the methods for evaluating the severity of liver disease noninvasively by estimating function or structure.

A pilot approach for quantitative assessment of liver fibrosis using ultrasound: preliminary results in 79 cases

BACKGROUND/AIMS

Ultrasound is noninvasive and useful to evaluate liver disease despite its operator dependency. This pilot study was conducted to quantitatively assess liver fibrosis using ultrasound.

METHODS

Fibrosis extraction ratios (FER) (fiber volume/total volume) of ultrasound and histological images of 8 autopsy specimens were compared. We also compared FER of ultrasound images from clinical patients (n=79) with histological fibrosis stages.

RESULTS

In the autopsy study, FER correlation coefficient between histological images and ultrasound images was 0.992. Regarding clinical patients, there was sufficient evidence to indicate differences in the distributions of FER for each fibrosis stage (Kruskal-Wallis test P<0.0001). With FER cut-off to distinguish > or =F2 from F0 and F1 defined as mean plus standard deviation of F0 and F1, sensitivity, specificity, positive predictive value, negative predictive value, and likelihood ratio were 62, 75, 78, 57%, and 2.47, respectively. Regarding HCV cohort (n=44), they were 55, 87, 89, 50%, and 4.14, respectively. Areas under receiver operating characteristic curves were 0.78, 0.79, 0.83 and 0.83 for > or =F1, > or =F2, > or =F3 and =F4, respectively. Regarding HCV cohort, they were 0.74, 0.71, 0.79 for > or =F2, > or =3 and =4, respectively.

CONCLUSIONS

The FER method has great potential for diagnosing liver fibrosis using ultrasound.

Factors affecting the quantitative liver-spleen scan in normal individuals

The quantitative liver-spleen scan (QLSS) can estimate the functional hepatic mass and the organ volumes by precise measurement of sulfur colloid (SC) distribution. The normal range determined in prior studies was estimated from patients with absence of chronic liver disease in which intense fasting appeared to produce slightly abnormal values. This study was to determine the effect of fasting or fed status and colloid particle size on quantitative measurements from the QLSS in a small cohort of normal individuals. Twelve persons without any medical problems had QLSS taken twice, 2 weeks apart, one fasting and one postprandial. Patients were scanned after injection of 5-6 mCi of SC; six patients were given solution A (5- to 12-microm particle size) and six patients solution B (2- to 12-microm particle size). SPECT and planar analysis were performed. SC distribution of total counts between the liver and the spleen {[L/(L + S)]t ratio}, liver-spleen index (LSI), and liver-bone marrow index (LBI) were calculated. The perfused hepatic mass (PHM) is the average of the LSI and LBI. Spleen and liver volumes are expressed as milliliters per pound ideal body weight (IBW). Results showed that the liver and spleen volumes (solution B postprandial, 9.27 +/- 2.48 and 1.47 +/- 0.57 ml/lb IBW, respectively) and LBI were not affected by the type of SC solution or by ingestion status. L/(L + S) total and pixel count ratios were significantly higher for solution B and postprandial studies. [L/(L + S)]t, LSI, and PHM increased significantly (P < 0.05) from fasting to postprandial for solution A (0.71 +/- 0.13 vs 0.79 +/- 0.08, 80 +/- 14 vs 91 +/- 8, and 102 +/- 10 vs 106 +/- 8, respectively) and for solution B (0.81 +/- 0.05 vs 0.90 +/- 0.02, 86 +/- 4 vs 95 +/- 3, and 101 +/- 5 vs 110 +/- 3). Neither fasting nor postprandial LSI and PHM were significantly different between solution A and solution B. We conclude the following. (1) The QLSS functional indices in "true" normal patients fall within the previously reported normal range. (2) Calculated liver and spleen volumes are not altered by fasting or sulfur colloid particle size. (3) Fasting significantly decreased the [L/(L + S)]t, LSI, and PHM. (4) A postprandial scan may be preferable since the normal values for [L/(L + S)]t, LSI, and PHM are greater, with a narrower range, than fasting values.