Recommendations on the Use of Magnetic Resonance Imaging for Collaborative Multicenter Studies in Primary Sclerosing Cholangitis

BISCIT: Biliary interventions in critically ill patients with secondary sclerosing cholangitis-a study protocol for a multicenter, randomized, controlled parallel group trial

BACKGROUND

Progress of cholangitis to cholangiosepsis is a frequent observation in patients with secondary sclerosing cholangitis in critically ill patients (SSC-CIP). Adequate biliary drainage may reduce episodes of cholangiosepsis and therefore stabilize liver function and improve survival. The primary objective of the BISCIT study is to demonstrate that scheduled biliary interventions will reduce incidence of cholangiosepsis, liver transplantation, or death in patients with SSC-CIP.

METHODS

A total of 104 patients will be randomized at ten study sites. Patients with SSC-CIP, confirmed by endoscopic retrograde cholangiography (ERC), will be randomized 1:1 either in the intervention group which will be treated with scheduled biliary interventions (i.e., therapeutic ERC) every 8 weeks for 6 months or in the control group which will receive standard of care. The randomization will be stratified by center. The composite primary efficacy endpoint is defined as (1) occurrence of death, (2) necessity of liver transplantation, or (3) occurrence of cholangiosepsis within 6 months following randomization.

DISCUSSION

Prospective evaluation of endoscopic treatment procedures is urgently needed to establish an evidence-based therapeutic treatment algorithm in SSC-CIP. A positive trial result could change the current standard of care for patients with SSC-CIP. The results of this study will be disseminated through presentations at international congresses, workshops, and peer-reviewed publications.

TRIAL REGISTRATION

The trial was registered at ClinicalTrials.gov (NCT05396755, date of registration: May 31, 2022, last update: May 31, 2022).

Imaging of the biliary tract

PURPOSE OF REVIEW

Magnetic resonance cholangiopancreatography (MRCP) has become the reference examination for the exploration of the biliary tract and has replaced endoscopic cholangiography for the analysis of the biliary tract because of its equivalent performance and its noninvasive character.

RECENT FINDINGS

Based on the International Primary Sclerosing Cholangitis (PSC) Study Group recommendations for MR imaging in PSC, two protocols can be distinguished for the imaging of biliary tract: a basic protocol and a more complete protocol. It is essential to know the main pitfalls in order not to wrongly describe biliary anomalies. In addition to the excellent performance of MR imaging with MRCP in analyzing the anatomy and the anomalies of the biliary tree, complementary techniques have recently been developed. Several MR prognostic factors have been described. New hepato-specific contrast agents are now available for assessment of the general and segmental liver function. MR Elastography and Diffusion-weighted MR sequences are accurate to evaluate the degree of hepatic fibrosis. Finally, images obtained in MRCP can be postprocessed by a software that will analyze and model the biliary tree in order to quantitatively evaluate the biliary system.

SUMMARY

Magnetic resonance imaging with its recent developments becomes by now an essential tool for the evaluation of biliary diseases.

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.

Fully automated detection of primary sclerosing cholangitis (PSC)-compatible bile duct changes based on 3D magnetic resonance cholangiopancreatography using machine learning

OBJECTIVES

To develop and evaluate a deep learning algorithm for fully automated detection of primary sclerosing cholangitis (PSC)-compatible cholangiographic changes on three-dimensional magnetic resonance cholangiopancreatography (3D-MRCP) images.

METHODS

The datasets of 428 patients (n = 205 with confirmed diagnosis of PSC; n = 223 non-PSC patients) referred for MRI including MRCP were included in this retrospective IRB-approved study. Datasets were randomly assigned to a training (n = 386) and a validation group (n = 42). For each case, 20 uniformly distributed axial MRCP rotations and a subsequent maximum intensity projection (MIP) were calculated, resulting in a training database of 7720 images and a validation database of 840 images. Then, a pre-trained Inception ResNet was implemented which was conclusively fine-tuned (learning rate 10^-3).

RESULTS

Applying an ensemble strategy (by binning of the 20 axial projections), the mean absolute error (MAE) of the developed deep learning algorithm for detection of PSC-compatible cholangiographic changes was lowered from 21 to 7.1%. Sensitivity, specificity, positive predictive (PPV), and negative predictive value (NPV) for detection of these changes were 95.0%, 90.9%, 90.5%, and 95.2% respectively.

CONCLUSIONS

The results of this study demonstrate the feasibility of transfer learning in combination with extensive image augmentation to detect PSC-compatible cholangiographic changes on 3D-MRCP images with a high sensitivity and a low MAE. Further validation with more and multicentric data is now desirable, as it is known that neural networks tend to overfit the characteristics of the dataset.

KEY POINTS

• The described machine learning algorithm is able to detect PSC-compatible cholangiographic changes on 3D-MRCP images with high accuracy. • The generation of 2D projections from 3D datasets enabled the implementation of an ensemble strategy to boost inference performance.

Effects of Tumor Necrosis Factor Antagonists in Patients With Primary Sclerosing Cholangitis

BACKGROUND & AIMS

Few patients with primary sclerosing cholangitis (PSC) and inflammatory bowel diseases (IBDs) are exposed to tumor necrosis factor (TNF) antagonists because of the often mild symptoms of IBD. We assessed the effects of anti-TNF agents on liver function in patients with PSC and IBD, and their efficacy in treatment of IBD.

METHODS

We performed a retrospective analysis of 141 patients with PSC and IBD receiving treatment with anti-TNF agents (infliximab or adalimumab) at 20 sites (mostly tertiary-care centers) in Europe and North America. We collected data on the serum level of alkaline phosphatase (ALP). IBD response was defined as either endoscopic response or, if no endoscopic data were available, clinical response, as determined by the treating clinician or measurements of fecal calprotectin. Remission was defined more stringently as endoscopic mucosal healing. We used linear regression analysis to identify factors associated significantly with level of ALP during anti-TNF therapy.

RESULTS

Anti-TNF treatment produced a response of IBD in 48% of patients and remission of IBD in 23%. There was no difference in PSC symptom frequency before or after drug exposure. The most common reasons for anti-TNF discontinuation were primary nonresponse of IBD (17%) and side effects (18%). At 3 months, infliximab-treated patients had a median reduction in serum level of ALP of 4% (interquartile range, reduction of 25% to increase of 19%) compared with a median 15% reduction in ALP in adalimumab-treated patients (interquartile range, reduction of 29% to reduction of 4%; P = .035). Factors associated with lower ALP were normal ALP at baseline (P < .01), treatment with adalimumab (P = .090), and treatment in Europe (P = .083).

CONCLUSIONS

In a retrospective analysis of 141 patients with PSC and IBD, anti-TNF agents were moderately effective and were not associated with exacerbation of PSC symptoms or specific side effects. Prospective studies are needed to investigate the association between use of adalimumab and reduced serum levels of ALP further.

Precision medicine in primary sclerosing cholangitis

Primary sclerosing cholangitis is a rare, complex autoimmune disease in relatively young patients. There is currently no treatment for the disease, resulting in high rates of advanced liver disease leading to death or liver transplantation. However, advances have been made in our understanding of the pathophysiological mechanisms of the disease, particularly from breakthroughs in the underlying genetics. Moreover, large international collaborations have generated important clinical data that have given greater detail on the different disease phenotypes and natural history, generating new risk prediction models. As a result, drug development may be designed to target specific disease mechanisms at known points of the disease natural history. Therefore, more drugs are entering phase II and III development, giving hope that soon patient-specific treatments may be available to treat this difficult disease.