Quantitative spleen and liver volume changes predict survival of patients with primary sclerosing cholangitis

The impact of hepatic and splenic volumetric assessment in imaging for chronic liver disease: a narrative review

Chronic liver disease is responsible for significant morbidity and mortality worldwide. Abdominal computed tomography (CT) and magnetic resonance imaging (MRI) can fully visualise the liver and adjacent structures in the upper abdomen providing a reproducible assessment of the liver and biliary system and can detect features of portal hypertension. Subjective interpretation of CT and MRI in the assessment of liver parenchyma for early and advanced stages of fibrosis (pre-cirrhosis), as well as severity of portal hypertension, is limited. Quantitative and reproducible measurements of hepatic and splenic volumes have been shown to correlate with fibrosis staging, clinical outcomes, and mortality. In this review, we will explore the role of volumetric measurements in relation to diagnosis, assessment of severity and prediction of outcomes in chronic liver disease patients. We conclude that volumetric analysis of the liver and spleen can provide important information in such patients, has the potential to stratify patients' stage of hepatic fibrosis and disease severity, and can provide critical prognostic information. CRITICAL RELEVANCE STATEMENT: This review highlights the role of volumetric measurements of the liver and spleen using CT and MRI in relation to diagnosis, assessment of severity, and prediction of outcomes in chronic liver disease patients. KEY POINTS: Volumetry of the liver and spleen using CT and MRI correlates with hepatic fibrosis stages and cirrhosis. Volumetric measurements correlate with chronic liver disease outcomes. Fully automated methods for volumetry are required for implementation into routine clinical practice.

Mendelian randomization analyses reveal causal relationship between liver volume and stroke

BACKGROUND

Observational studies have suggested a potential association between abdominal viscera volume and increased risk of stroke. However, the causal relationship remains unclear. This study aims to utilize Mendelian randomization (MR) to explore the genetic causal relationship between them.

METHODS

We conducted MR analysis to study the causal effects of five abdominal viscera volumes on stroke. The genetic variations of abdominal viscera volume were obtained from the UK Biobank, and the summary data for stroke and ischemic stroke were acquired from the MEGASTROKE consortium. This study employed inverse variance weighting (IVW), MR Egger, and weighted median methods. IVW served as the primary MR analysis method, supplemented by other sensitivity analyses to validate the robustness of the results.

RESULTS

We found that liver volume can causally increase the risk of stroke [odds ratio (OR): 1.13, 95 % confidence interval (CI): 1.03-1.25, P = 0.013] and ischemic stroke (OR: 1.14, 95 % CI: 1.03-1.26, P = 0.012). No causal relationships between other abdominal viscera volumes and stroke and ischemic stroke appeared to be present (P > 0.05). Sensitivity analyses confirmed the robustness of the results.

CONCLUSION

Our research findings indicate a causal relationship between liver volume and stroke, highlighting the potential role of liver volume in the onset of stroke. However, further basic and clinical research is needed to delve into the specific mechanisms underlying the relationship between liver volume and stroke, and to implement interventions aimed at reducing the impact of liver volume on stroke risk.

Deep learning multi-organ segmentation for whole mouse cryo-images including a comparison of 2D and 3D deep networks

Cryo-imaging provided 3D whole-mouse microscopic color anatomy and fluorescence images that enables biotechnology applications (e.g., stem cells and metastatic cancer). In this report, we compared three methods of organ segmentation: 2D U-Net with 2D-slices and 3D U-Net with either 3D-whole-mouse or 3D-patches. We evaluated the brain, thymus, lung, heart, liver, stomach, spleen, left and right kidney, and bladder. Training with 63 mice, 2D-slices had the best performance, with median Dice scores of > 0.9 and median Hausdorff distances of < 1.2 mm in eightfold cross validation for all organs, except bladder, which is a problem organ due to variable filling and poor contrast. Results were comparable to those for a second analyst on the same data. Regression analyses were performed to fit learning curves, which showed that 2D-slices can succeed with fewer samples. Review and editing of 2D-slices segmentation results reduced human operator time from ~ 2-h to ~ 25-min, with reduced inter-observer variability. As demonstrations, we used organ segmentation to evaluate size changes in liver disease and to quantify the distribution of therapeutic mesenchymal stem cells in organs. With a 48-GB GPU, we determined that extra GPU RAM improved the performance of 3D deep learning because we could train at a higher resolution.

Reporting standards for primary sclerosing cholangitis using MRI and MR cholangiopancreatography: guidelines from MR Working Group of the International Primary Sclerosing Cholangitis Study Group

Primary sclerosing cholangitis (PSC) is a chronic inflammatory disorder affecting the bile ducts and is characterized by biliary strictures, progressive liver parenchymal fibrosis, and an increased risk of hepatobiliary malignancies primarily cholangiocarcinoma (CCA). PSC may lead to portal hypertension, liver decompensation, and liver failure with the need for liver transplantation. Magnetic resonance imaging (MRI)/magnetic resonance cholangiopancreatography (MRCP) are considered the imaging standard for diagnosis and follow-up in patients with PSC. Currently, there are no universally accepted reporting standards and definitions for MRI/MRCP features. Controversies exist about the definition of a high-grade stricture and there is no widely agreed approach to their management. The members of the MRI working group of the International Primary Sclerosing Cholangitis Study Group (IPSCSG) sought to define terminologies and reporting standards for describing MRI/MRCP features that would be applied to diagnosis and surveillance of disease progression, and potentially for evaluating treatment response in clinical trials. In this extensive review, the technique of MRI/MRCP and assessment of image quality for the evaluation of PSC is briefly described. The definitions and terminologies for severity and length of strictures, duct wall thickening and hyperenhancement, and liver parenchyma signal intensity changes are outlined. As CCA is an important complication of PSC, standardized reporting criteria for CCA developing in PSC are summarized. Finally, the guidelines for reporting important changes in follow-up MRI/MRCP studies are provided. KEY POINTS: • Primary sclerosing cholangitis is a chronic inflammatory disorder affecting the bile ducts, causing biliary strictures and liver fibrosis and an increased risk of cholangiocarcinoma. • This consensus document provides definitions and suggested reporting standards for MRI and MRCP features of primary sclerosing cholangitis, which will allow for a standardized approach to diagnosis, assessment of disease severity, follow-up, and detection of complications. • Standardized definitions and reporting of MRI/MRCP features of PSC will facilitate comparison between studies, promote longitudinal assessment during management, reduce inter-reader variability, and enhance the quality of care and communication between health care providers.

The combination of Child-Pugh score and quantitative CT-based spleen volume could predict the risk of hepatic encephalopathy after transjugular intrahepatic portosystemic shunt creation

PURPOSE

Hepatic encephalopathy (HE) is a common complication in patients undergoing transjugular intrahepatic portosystemic shunt (TIPS). The objective of this study was to assess the prognostic factors and make risk stratification of post-TIPS HE.

METHODS

This was a retrospective cohort study consisting of cirrhotic patients who had undergone TIPS creation at our center from November 2015 to August 2020. The baseline characteristics including spleen volume (SVol) and other markers were collected. The univariate and multivariate Cox regression analyses were used to identify independent predictors of post-TIPS overt HE (OHE).

RESULTS

Higher Child-Pugh (CP) score (HR 1.334, 95% CI 1.090-1.632, P = 0.005) and smaller SVol (HR 0.999, 95% CI 0.997-1.000, P = 0.004) were identified as the independent risk factors for post-TIPS OHE. And a time-dependent ROC analysis was used to determine the cutoff values of CP score and SVol, which were respectively 6.5 and 773 cm³. Subsequently, the CP-SVol grading system was developed to divide patients into three risk grades according to the above two cutoff values. Kaplan-Meier analysis showed that the cumulative rates of patients free of OHE in Grade 1, 2 and 3 were respectively 96.4% ± 3.5%, 82.1 ± 4.7%, and 59.3% ± 6.4%, which were in descending order (Log rank P < 0.001).

CONCLUSION

SVol might be a novel marker to predict the prognosis of post-TIPS OHE, and the proposed CP-SVol grading system composed of CP score and SVol achieved a superior predictive performance.

Spatial heterogeneity of hepatic fibrosis in primary sclerosing cholangitis vs. viral hepatitis assessed by MR elastography

Spatial heterogeneity of hepatic fibrosis in primary sclerosing cholangitis (PSC) in comparison to viral hepatitis was assessed as a potential new biomarker using MR elastography (MRE). In this proof-of-concept study, we hypothesized a rather increased heterogeneity in PSC and a rather homogeneous distribution in viral hepatitis. Forty-six consecutive subjects (PSC: n = 20, viral hepatitis: n = 26) were prospectively enrolled between July 2014 and April 2017. Subjects underwent multifrequency MRE (1.5 T) using drive frequencies of 35–60 Hz and generating shear-wave speed (SWS in m/s) maps as a surrogate of stiffness. The coefficient of variation (CV in %) was determined to quantify fibrosis heterogeneity. Mean SWS and CV were 1.70 m/s and 21% for PSC, and 1.84 m/s and 18% for viral hepatitis. Fibrosis heterogeneity was significantly increased for PSC (P = 0.04) while no difference was found for SWS of PSC and viral hepatitis (P = 0.17). Global hepatic stiffness was similar in PSC and viral hepatitis groups, but spatial heterogeneity may reveal spatial patterns of stiffness changes towards enhanced biophysics-based diagnosis by MRI.

Impact of TIPS on Splenic Volume and Thrombocytopenia

OBJECTIVE. Splenomegaly and thrombocytopenia are common complications in patients with cirrhosis. The present study aimed to evaluate changes in splenic volumes and platelet counts after TIPS insertion. MATERIALS AND METHODS. A total of 104 patients who had a diagnosis of portal hypertension and had undergone TIPS placement between November 2015 and August 2019 were enrolled in this retrospective cohort study. We retrospectively calculated splenic volumes before TIPS placement and at 1-2 and 6-12 months after TIPS placement and monitored the platelet count at 1, 3, 6, and 12 months after TIPS placement. RESULTS. The mean (± SD) portal pressure gradient before TIPS placement was 28.3 ± 4.6 mm Hg; after TIPS placement, it was 11.3 ± 4.5 mm Hg (p < .001). The mean splenic volume of all 104 patients before TIPS placement was 868 ± 409 cm³, and at 1-2 months after TIPS placement, it was 710 ± 336 cm³ (p < .001). Among the 43 patients for whom splenic volume data were available at both 1-2 and 6-12 months after TIPS placement, the mean splenic volume decreased from 845 ± 342 cm³ to 691 ± 301 cm³ and then to 674 ± 333 cm³, respectively. Correspondingly, the number of patients with severe thrombocytopenia decreased from 25 patients (35.7%) before the TIPS procedure to 16 patients (22.9%) in the 1-2 months after TIPS placement and then to 11 patients (15.7%) in the 6-12 months after TIPS implantation. The increase in the platelet count was significantly correlated with decreasing splenic volume (r² = 0.3735; p < .001). CONCLUSION. In most patients, TIPS placement resulted in a significant decrease in splenic volume and a significant increase in the platelet count during the same period.

Advances in Imaging of Diffuse Parenchymal Liver Disease

There are >1.5 billion people with chronic liver disease worldwide, causing liver diseases to be a significant global health issue. Diffuse parenchymal liver diseases, including hepatic steatosis, fibrosis, metabolic diseases, and hepatitis cause chronic liver injury and may progress to fibrosis and eventually hepatocellular carcinoma. As early diagnosis and treatment of these diseases impact the progression and outcome, the need for assessment of the liver parenchyma has increased. While the current gold standard for evaluation of the hepatic parenchymal tissue, biopsy has disadvantages and limitations. Consequently, noninvasive methods have been developed based on serum biomarkers and imaging techniques. Conventional imaging modalities such as ultrasound, computed tomography scan, and magnetic resonance imaging provide noninvasive options for assessment of liver tissue. However, several recent advances in liver imaging techniques have been introduced. This review article focuses on the current status of imaging methods for diffuse parenchymal liver diseases assessment including their diagnostic accuracy, advantages and disadvantages, and comparison between different techniques.

Comparison of liver stiffness measurement with MRE and liver and spleen volumetry for prediction of disease severity and hepatic decompensation in patients with primary sclerosing cholangitis

PURPOSE

To compare liver stiffness measurement (LSM) with magnetic resonance elastography (MRE) and liver and spleen volumetry for prediction of disease severity and hepatic decompensation in primary sclerosing cholangitis (PSC).

METHODS

This retrospective study was approved by the institutional review board. Magnetic resonance imaging (MRI) and MRE studies were reviewed, and mean LSM of entire liver, right lobe and left lobe, total liver, right lobe, left lobe, caudate lobe, and spleen volumes were calculated. Qualitative evaluation of lobar atrophy or hypertrophy and presence of macronodular regeneration (MNR) was recorded. Statistical analysis was performed to evaluate correlations between LSM, volumetry measurements, and Mayo risk score. Univariate and multivariate analyses were performed to predict hepatic decompensation.

RESULTS

A total of 266 patients with PSC were included in the study. Lobar stiffness measures were higher in the presence of relative lobe atrophy. Mean LSM was higher in the presence of MNR. Significant correlations were observed between mean LSM and volumetry measurements with a fair correlation between LSM and spleen volume (r_s = 0.526, p < 0.0001). Among the measurements, the best correlation was observed between mean LSM and Mayo risk score (r_s = 0.646, p < 0.0001). In the multivariate analyses, mean LSM and Mayo risk score were significantly associated with liver decompensation (hazard ratio, 1.18; 95%CI 1.02-1.36 and hazard ratio, 1.65; 95%CI 1.08-2.53, respectively).

CONCLUSION

LSM with MRE performs significantly better than liver and spleen volumes for prediction of both disease severity and hepatic decompensation.