Follow-up magnetic resonance imaging/3D-magnetic resonance cholangiopancreatography in patients with primary sclerosing cholangitis: challenging for experts to interpret

Quantitative MRCP and metrics of bile duct disease over time in patients with primary sclerosing cholangitis: A prospective study

BACKGROUND

Imaging markers of biliary disease in primary sclerosing cholangitis (PSC) have potential for use in clinical and trial disease monitoring. Herein, we evaluate how quantitative magnetic resonance cholangiopancreatography (MRCP) metrics change over time, as per the natural history of disease.

METHODS

Individuals with PSC were prospectively scanned using non-contrast MRCP. Quantitative metrics were calculated using MRCP+ post-processing software to assess duct diameters and dilated and strictured regions. Additionally, a hepatopancreatobiliary radiologist (blinded to clinical details, biochemistry and quantitative biliary metrics) reported each scan, including ductal disease assessment according to the modified Amsterdam Cholangiographic Score (MAS).

RESULTS

At baseline, 14 quantitative MRCP+ metrics were found to be significantly different in patients with PSC (N = 55) compared to those with primary biliary cholangitis (N = 55), autoimmune hepatitis (N = 57) and healthy controls (N = 18). In PSC specifically, baseline metrics quantifying the number of strictures and the number and length of bile ducts correlated with the MAS, transient elastography and serum ALP values (p < 0.01 for all correlations). Over a median 371-day follow-up (range: 364-462), 29 patients with PSC underwent repeat MRCP, of whom 15 exhibited quantitative changes in MRCP+ metrics. Compared to baseline, quantitative MRCP+ identified an increasing number of strictures over time (p < 0.05). Comparatively, no significant differences in biochemistry, elastography or the MAS were observed between timepoints. Quantitative MRCP+ metrics remained stable in non-PSC liver disease.

CONCLUSION

Quantitative MRCP+ identifies changes in ductal disease over time in PSC, despite stability in biochemistry, liver stiffness and radiologist-derived cholangiographic assessment (trial registration: ISRCTN39463479).

Primary Sclerosing Cholangitis: Diagnostic Criteria

Primary sclerosing cholangitis is a chronic cholestatic liver disease characterized by inflammation and fibrosis of intra- and/or extrahepatic bile ducts leading to the formation of multifocal strictures alternated to bile duct dilatations. The diagnosis of the most common subtype of the disease, the large duct PSC, is based on the presence of elevation of cholestatic indices, the association of typical cholangiographic findings assessed by magnetic resonance cholangiography and the exclusion of causes of secondary sclerosing cholangitis. Liver biopsy is not routinely applied for the diagnosis of large duct PSC but is mandatory in the case of suspicion of small duct PSC or overlap with autoimmune hepatitis.

Interobserver agreement and prognostic value of image-based scoring systems in patients with primary sclerosing cholangitis

BACKGROUND

Primary sclerosing cholangitis (PSC) is a cholestatic liver disease that progresses to cirrhosis and liver failure. The Anali and Amsterdam scores are based upon imaging features on MRI and ERCP, respectively.

AIMS

We aimed to compare the interobserver variability and performances of these scores.

METHODS

Patients with PSC with at least 1 MRCP were included. Images were independently scored by 2 experts. Agreement and prognostic performance with a primary end point of hepatic decompensation was assessed.

RESULTS

Fifty-nine patients were included (67.8% male, 86.4% IBD). Interobserver agreement for the Anali and Amsterdam scores were moderate (k = 0.49; 95% CI 0.35-0.64 and k = 0.43; 95% CI 0.30-0.56, respectively). Among the Anali components, dysmorphy (caudate/right lobe ratio > 0.9) had fair agreement (k = 0.37; 95% CI 0.14-0.60) and portal hypertension (k = 0.64, 95% CI 0.32-0.89) and intrahepatic dilation (k = 0.70; 95% CI 0.53-0.87) had substantial agreement. The Amsterdam extrahepatic and intrahepatic scores had fair agreement (k = 0.38; 95% CI 0.23-0.52) and moderate agreement (k = 0.50; 95% CI 0.34-0.67), respectively. Anali score (HR 5.90, 95% CI 1.64-21.21), total bilirubin (HR = 3.23; 95% Cl 1.06-9.91), and age (HR = 1.05; 95% CI 1.00-1.11) were independent predictors of hepatic decompensation. Mayo risk score and Anali score had good discriminative ability with c-statistics of 0.78 (CI 0.59-0.96) and 0.76 (CI 0.56-0.91). Anali score remained an independent predictor after adjusting for Mayo risk score.

CONCLUSION

Anali score adds additional predictive value for hepatic decompensation in patients with PSC.

Diagnosis of functional strictures in patients with primary sclerosing cholangitis using hepatobiliary contrast-enhanced MRI: a proof-of-concept study

OBJECTIVES

PSC strictures are routinely diagnosed on T2-MRCP as dominant- (DS) or high-grade stricture (HGS). However, high inter-observer variability limits their utility. We introduce the "potential functional stricture" (PFS) on T1-weighted hepatobiliary-phase images of gadoxetic acid-enhanced MR cholangiography (T1-MRC) to assess inter-reader agreement on diagnosis, location, and prognostic value of PFS on T1-MRC vs. DS or HGS on T2-MRCP in PSC patients, using ERCP as the gold standard.

METHODS

Six blinded readers independently reviewed 129 MRIs to diagnose and locate stricture, if present. DS/HGS was determined on T2-MRCP. On T1-MRC, PFS was diagnosed if no GA excretion was seen in the CBD, hilum or distal RHD, or LHD. If excretion was normal, "no functional stricture" (NFS) was diagnosed. T1-MRC diagnoses (NFS = 87; PFS = 42) were correlated with ERCP, clinical scores, labs, splenic volume, and clinical events. Statistical analyses included Kaplan-Meier curves and Cox regression.

RESULTS

Interobserver agreement was almost perfect for NFS vs. PFS diagnosis, but fair to moderate for DS and HGS. Forty-four ERCPs in 129 patients (34.1%) were performed, 39 in PFS (92.9%), and, due to clinical suspicion, five in NFS (5.7%) patients. PFS and NFS diagnoses had 100% PPV and 100% NPV, respectively. Labs and clinical scores were significantly worse for PFS vs. NFS. PFS patients underwent more diagnostic and therapeutic ERCPs, experienced more clinical events, and reached significantly more endpoints (p < 0.001) than those with NFS. Multivariate analysis identified PFS as an independent risk factor for liver-related events.

CONCLUSION

T1-MRC was superior to T2-MRCP for stricture diagnosis, stricture location, and prognostication.

CLINICAL RELEVANCE STATEMENT

Because half of PSC patients will develop clinically-relevant strictures over the course of the disease, earlier more confident diagnosis and correct localization of functional stricture on gadoxetic acid-enhanced MRI may optimize management and improve prognostication.

KEY POINTS

• There is no consensus regarding biliary stricture imaging features in PSC that have clinical relevance. • Twenty-minute T1-weighted MRC images correctly classified PSC patients with potential (PFS) vs with no functional stricture (NFS). • T1-MRC diagnoses may reduce the burden of diagnostic ERCPs.

Prognostic role of magnetic resonance imaging of the abdomen with intravenous contrast and magnetic resonance cholangiopancreatography in primary sclerosing cholangitis

Objective

To evaluate the usefulness of Anali scores, determined by magnetic resonance imaging, for predicting the prognosis of primary sclerosing cholangitis (PSC) and to analyze interobserver variability, as well as to assess the impact of periportal edema and heterogeneous signal intensity on diffusion-weighted imaging of the liver.

Materials and Methods

This was a retrospective cohort study of 29 patients with PSC and baseline magnetic resonance imaging. Anali scores, without gadolinium (0-5 points) and with gadolinium (0-2 points), were calculated by two radiologists. Clinical end-points included liver transplantation, cirrhotic decompensation, and death. We calculated intraclass correlation coefficients (ICCs) for interobserver agreement on the Anali scores, performed Kaplan-Meier survival analysis comparing event-free survival among the score strata, and calculated the areas under receiver operating characteristic curves to determine sensitivity and specificity.

Results

Among the patients with a clinical event, the median Anali score was 4 (interquartile range [IQR], 2-5) without gadolinium and 2 (IQR, 1-2) with gadolinium, compared with 1 (IQR, 1.0-2.5) and 1 (IQR, 0.25-1.0), respectively, among those without a clinical event. The ICC was 0.79 (95% confidence interval: 0.57-0.91) for the Anali score with gadolinium and 0.99 (95% confidence interval: 0.98-0.99) for the Anali score without gadolinium. Periportal edema and heterogeneous signal intensity in the liver on diffusion-weighted imaging showed no statistical impact on clinical events (p = 0.65 and p = 0.5, respectively).

Conclusion

Anali scores correlate with clinical events in PSC, with a high level of interobserver agreement.

A composite score using quantitative magnetic resonance cholangiopancreatography predicts clinical outcomes in primary sclerosing cholangitis

Background & Aims

Magnetic resonance cholangiopancreatography (MRCP) for evaluation of biliary disease currently relies on subjective assessment with limited prognostic value because of the lack of quantitative metrics. Artificial intelligence-enabled quantitative MRCP (MRCP+) is a novel technique that segments biliary anatomy and provides quantitative biliary tree metrics. This study investigated the utility of MRCP+ as a prognostic tool for the prediction of clinical outcomes in primary sclerosing cholangitis (PSC).

Methods

MRCP images of patients with PSC were post-processed using MRCP+ software. The duration between the MRCP and clinical event (liver transplantation or death) was calculated. Survival analysis and stepwise Cox regression were performed to investigate the optimal combination of MRCP+ metrics for the prediction of clinical outcomes. The resulting risk score was validated in a separate validation cohort and compared with an existing prognostic score (Mayo risk score).

Results

In this retrospective study, 102 patients were included in a training cohort and a separate 50 patients formed a validation cohort. Between the two cohorts, 34 patients developed clinical outcomes over a median duration of 3 years (23 liver transplantations and 11 deaths). The proportion of bile ducts with diameter 3-5 mm, total bilirubin, and aspartate aminotransferase were independently associated with transplant-free survival. Combined as a risk score, the overall discriminative performance of the MRCP+ risk score (M+BA) was excellent; area under the receiver operator curve 0.86 (95% CI: 0.77, 0.95) at predicting clinical outcomes in the validation cohort with a hazard ratio 5.8 (95% CI: 1.5, 22.1). This was superior to the Mayo risk score.

Conclusions

A composite score combining MRCP+ with total bilirubin and aspartate aminotransferase (M+BA) identified PSC patients at high risk of liver transplantation or death. Prospective studies are warranted to evaluate the clinical utility of this novel prognostic tool.

Impact and Implications

Primary sclerosis cholangitis (PSC) is a disease of the biliary tree where inflammation and fibrosis cause areas of narrowing (strictures) and expansion (dilatations) within the biliary ducts leading to liver failure and/or cancer (cholangiocarcinoma). In this study, we demonstrate that quantitative assessment of the biliary tree can better identify patients with PSC who are at high risk of either death or liver transplantation than a current blood-based risk score (Mayo risk score).

DeePSC: A Deep Learning Model for Automated Diagnosis of Primary Sclerosing Cholangitis at Two-dimensional MR Cholangiopancreatography

Purpose

To develop, train, and validate a multiview deep convolutional neural network (DeePSC) for the automated diagnosis of primary sclerosing cholangitis (PSC) on two-dimensional MR cholangiopancreatography (MRCP) images.

Materials and Methods

This retrospective study included two-dimensional MRCP datasets of 342 patients (45 years ± 14 [SD]; 207 male patients) with confirmed diagnosis of PSC and 264 controls (51 years ± 16; 150 male patients). MRCP images were separated into 3-T (n = 361) and 1.5-T (n = 398) datasets, of which 39 samples each were randomly chosen as unseen test sets. Additionally, 37 MRCP images obtained with a 3-T MRI scanner from a different manufacturer were included for external testing. A multiview convolutional neural network was developed, specialized in simultaneously processing the seven images taken at different rotational angles per MRCP examination. The final model, DeePSC, derived its classification per patient from the instance expressing the highest confidence in an ensemble of 20 individually trained multiview convolutional neural networks. Predictive performance on both test sets was compared with that of four licensed radiologists using the Welch t test.

Results

DeePSC achieved an accuracy of 80.5% ± 1.3 (sensitivity, 80.0% ± 1.9; specificity, 81.1% ± 2.7) on the 3-T and 82.6% ± 3.0 (sensitivity, 83.6% ± 1.8; specificity, 80.0% ± 8.9) on the 1.5-T test set and scored even higher on the external test set (accuracy, 92.4% ± 1.1; sensitivity, 100.0% ± 0.0; specificity, 83.5% ± 2.4). DeePSC outperformed radiologists in average prediction accuracy by 5.5 (P = .34, 3 T) and 10.1 (P = .13, 1.5 T) percentage points.

Conclusion

Automated classification of PSC-compatible findings based on two-dimensional MRCP was achievable and demonstrated high accuracy on internal and external test sets.Keywords: Neural Networks, Deep Learning, Liver Disease, MRI, Primary Sclerosing Cholangitis, MR Cholangiopancreatography Supplemental material is available for this article. © RSNA, 2023.

Prospective surveillance for cholangiocarcinoma in unselected individuals with primary sclerosing cholangitis

BACKGROUND & AIMS

The evidence for hepatobiliary tumour surveillance in patients with primary sclerosing cholangitis (PSC) is scarce. In this study, we aimed to prospectively evaluate cholangiocarcinoma (CCA) surveillance with yearly MRI with cholangiopancreatography (MRI/MRCP) in a nationwide cohort.

METHODS

In total, 512 patients with PSC from 11 Swedish hospitals were recruited. The study protocol included yearly clinical follow-ups, liver function tests and contrast-enhanced MRI/MRCP and carbohydrate antigen (CA) 19-9. Patients with severe/progressive bile duct changes on MRI/MRCP were further investigated with endoscopic retrograde cholangiopancreatography. Patients were followed for 5 years or until a diagnosis of CCA, liver transplantation (LT) and/or death. Risk factors associated with CCA were analysed with Cox regression.

RESULTS

Eleven patients (2%) were diagnosed with CCA, and two (0.5%) with high-grade bile duct dysplasia. Severe/progressive bile duct changes on MRI/MRCP were detected in 122 patients (24%), of whom 10% had an underlying malignancy. The primary indication for LT (n = 54) was biliary dysplasia in nine patients (17%) and end-stage liver disease in 45 patients (83%), of whom three patients (7%) had unexpected malignancy in the explants. The median survival for patients with CCA was 13 months (3-22 months). Time to diagnosis of high-grade dysplasia and/or hepatobiliary malignancy was significantly associated with severe/progressive bile duct changes on MRI/MRCP (hazard ratio 10.50; 95% CI 2.49-44.31) and increased levels of CA19-9 (hazard ratio 1.00; 95% CI 1.00-1.01).

CONCLUSION

In an unselected cohort of patients with PSC, yearly CA19-9 and MRI/MRCP surveillance followed by ERCP was ineffective in detecting cancer early enough to support long-term survival. Given the low occurrence of CCA, studies on individualised strategies for follow-up and improved diagnostic methods for PSC-related CCA are warranted.

IMPACT AND IMPLICATIONS

A prospective nationwide 5-year study was conducted to evaluate yearly cholangiocarcinoma surveillance using MRI and CA19-9 in patients with primary sclerosing cholangitis. Only 2% of the patients were diagnosed with cholangiocarcinoma during follow-up and their prognosis remained poor despite surveillance. This surveillance strategy failed to detect cancer early enough to support long-term survival. Therefore, individualised strategies and improved diagnostic methods will be required to improve the early detection of cholangiocarcinoma in patients with primary sclerosing cholangitis.

Risk stratification in primary sclerosing cholangitis

Primary sclerosing cholangitis (PSC) is a chronic liver disorder commonly affecting young patients and associated with uncertain prognosis and elevated risk of end-stage liver disease and hepatobiliary cancer. Rate of progression in PSC is heterogeneous and accurately predicting the disease course is of paramount importance to clinical practice and interventional trial design. So far, efforts have brought to the development of models looking at short-to-middle-term outcome using composite models including clinical, laboratory, radiological and histological parameters with limited performance. In the era of whole genome sequencing and digital innovation, the time is ripe for the development of stratified medicine in PSC. Efforts should be directed toward developing well-phenotyped cohorts of patients with longitudinal follow-up across sustained periods of time, application of novel image-processing technology, and biomarker discovery using multiomics platforms.

Quantitative MR in Paediatric Patients with Wilson Disease: A Case Series Review

Wilson disease (WD) is a liver disorder characterized by improper copper metabolism. Although non-invasive tools are currently used to support diagnosis and management, this is still an area of unmet need, as patients present with a wide range of symptoms. Our aim was to investigate the potential utility of multiparametric magnetic resonance imaging (mpMRI) and quantitative magnetic resonance cholangiopancreatography (MRCP+) to support patient management. MRI examinations of 7 children and young adults aged 8–16 years (six at diagnosis) were performed alongside a standard of care clinical and histological examination. Images were quantitatively analyzed to derive metrics of liver (corrected T1 (cT1; fibro-inflammation), MR liver fat (proton density fat fraction; PDFF)), and biliary health (MRCP+). MRI–PDFF provided a more dynamic characterization of fat compared with that provided by ultrasound. Those with elevated histological scores of fibrosis, inflammation, and steatosis had elevated mpMRI values. MRCP+ managed to identify dilatations in the biliary tree which were not observed during the standard of care examination. mpMRI and MRCP+ metrics show early promise as markers to assess both liver and biliary health in Wilson disease. Investigations to understand and explore the utility of these markers are warranted and should be performed.

A Quantitative Magnetic Resonance Cholangiopancreatography Metric of Intrahepatic Biliary Dilatation Severity Detects High-Risk Primary Sclerosing Cholangitis

Magnetic resonance imaging with magnetic resonance cholangiopancreatography (MRI‐MRCP) in primary sclerosing cholangitis (PSC) is currently based on qualitative assessment and has high interobserver variability. We investigated the utility and performance of quantitative metrics derived from a three‐dimensional biliary analysis tool in adult patients with PSC. MRI‐MRCP, blood‐based biomarkers, and FibroScan were prospectively performed in 80 participants with large‐duct PSC and 20 healthy participants. Quantitative analysis was performed using MRCP+ (Perspectum Ltd., United Kingdom), and qualitative reads were performed by radiologists. Inter‐reader agreements were compared. Patients were classified into high risk or low risk for disease progression, using Mayo risk score (MRS), Amsterdam‐Oxford model (AOM), upper limit of normal (ULN) alkaline phosphatase (ALP), disease distribution, and presence of dominant stricture. Performance of noninvasive tools was assessed using binomial logistic regressions and receiver operating characteristic curve analyses. Quantitative biliary metrics performed well to distinguish abnormal from normal bile ducts (P < 0.0001). Interobserver agreements for MRCP+ dilatation metrics (intraclass correlation coefficient, 0.90‐0.96) were superior to modified Amsterdam intrahepatic stricture severity score (κ = 0.74) and Anali score (κ = 0.38). MRCP+ intrahepatic dilatation severity showed excellent performance to classify patients into high‐risk and low‐risk groups, using predictors of disease severity as the reference (MRS, P < 0.0001; AOM, P = 0.0017; 2.2 × ULN ALP, P = 0.0007; 1.5 × ULN ALP, P = 0.0225; extrahepatic disease, P = 0.0331; dominant stricture, P = 0.0019). MRCP+ intrahepatic dilatation severity was an independent predictor of MRS >0 (odds ratio, 31.3; P = 0.035) in the multivariate analysis. Conclusion: Intrahepatic biliary dilatation severity calculated using MRCP+ is elevated in patients with high‐risk PSC and may be used as an adjunct for risk stratification in PSC. This exploratory study has provided the groundwork for examining the utility of novel quantitative biliary metrics in multicenter studies.

Assessment of prognostic value and interreader agreement of ANALI scores in patients with primary sclerosing cholangitis

PURPOSE

ANALI-scores are two prognostic magnetic resonance imaging (MRI)-based scores developed for patients with primary sclerosing cholangitis (PSC). Our study aims to assess the interreader agreement between expert radiologists of the two ANALI-scores and of the radiological parameters they utilize, and to test the prognostic performance of the scores in our population.

METHOD

Three radiologists evaluated MRIs of 98 PSC-patients from a prospectively collected cohort with median follow-up of 6.7 years. Each parameter of ANALI-scores was assessed, and the scores were calculated. Interreader agreement was assessed with intraclass correlation coefficient (ICC). After consensus reading was reached, the prognostic value of ANALI-scores was assessed with Cox regression, and outcome-free survival rates were evaluated with Kaplan-Meier estimates.

RESULTS

The ANALI-score without gadolinium had poor to moderate (ICC = 0.56, 95 %CI: 0.42-0.68) and with gadolinium poor (ICC = 0.30, 95 %CI: 0.16-0.44) agreement. Liver deformity (ICC = 0.28, 95 %CI: 0.13-0.44) and parenchymal enhancement heterogeneity (ICC = 0.24, 95 %CI: 0.12-0.38) had poor agreement. Portal hypertension had poor to moderate (ICC = 0.48, 95 %CI: 0.36-0.59) and dilatation of the intrahepatic ducts had moderate (ICC = 0.64, 95 %CI: 0.54-0.73) agreement. Hazard ratios for liver-related death, transplantation or cirrhosis decompensation of the ANALI-scores with and without gadolinium were 3.53 (95 %CI: 1.40-8.93) and 2.25 (95 %CI: 1.56-3.24), respectively. Outcome-free survival was better for patients with low ANALI-scores.

CONCLUSIONS

The ANALI-scores show poor to moderate agreement, which challenges their usefulness in clinical practice. They are associated with clinical outcomes, confirming the value of imaging in prognosis of PSC, but need further multicenter evaluation.

Novel analysis using magnetic resonance cholangiography for patients with pancreaticobiliary maljunction

PURPOSE

We used a novel diagnostic Fourier transform (FT) algorithm of the entire extrahepatic bile duct (EHBD) measured by magnetic resonance cholangiography (MRC) to evaluate subtle deformation of bile duct lumen, indicating the malignant potential of EHBD, in patients with pancreaticobiliary maljunction (PBMJ) and in a comparative group of controls without PBMJ.

METHODS

From the workstation, the EHBD lumen was traced automatically and a 2D diagram cross section was measured at 0.5 mm-longitudinal intervals. The FT-based integrated power spectral density function value (FTPSDI) of the diameter or area (mm² or mm⁴/Hz) and the phase value distribution entropy (PVDE) were also measured.

RESULTS

There were 16 patients with undilated PBMJ and 7 with dilated PBMJ. The control group comprised 10 patients with a normal bile duct, 20 with bile duct carcinoma (BDC), and 1 with primary sclerosing cholangitis. Both the diameter and area of the dilated bile ducts and the ducts with early- or advanced-stage BDC were significantly greater than those of the normal duct (p < 0.05). The undilated type of PBMJ tended to have a larger FTPSDI diameter than a normal bile duct, which had a smaller diameter than the dilated type of PBMJ or BDC. BDC had a significantly larger FTPSDI diameter (p < 0.05) and the cutoff value for accuracy was 168 mm² Hz^-1.

CONCLUSION

The novel mathematical FTPSDI is a promising indicator of whether preventive EHBD resection is necessary for patients with PBMJ, which can be widely applied in the early diagnosis of other biliary diseases.

Quantitative multiparametric MRI as a non-invasive stratification tool in children and adolescents with autoimmune liver disease

Autoimmune hepatitis (AIH) and autoimmune sclerosing cholangitis (ASC) are two very closely related autoimmune liver diseases with overlapping clinical features and similar management strategies. The purpose of this study was to assess the utility of quantitative imaging markers to distinguish ASC from AIH in paediatrics. 66 participants (N = 52 AIH, N = 14 ASC) aged 14.4 ± 3.3 years scheduled to undergo routine biopsy and baseline serum liver biochemistry testing were invited to undergo MRI (non-contrast abdominal MRI and 3D fast spin-echo MRCP). Multiparametric MRI was used to measure fibro-inflammation with corrected T1 (cT1), while the biliary tree was modelled   using quantitative MRCP (MRCP +). Mann–Whitney U tests were performed to compare liver function tests with imaging markers between patient groups (ASC vs AIH). Receiver operating characteristic curves and stepwise logistic regressions were used to identify the best combination of markers to discriminate between ASC and AIH. Correlations between liver function tests and imaging markers were performed using Spearman’s rank correlation. cT1 was significantly correlated with liver function tests (range 0.33 ≤ R ≤ 56, p < 0.05), as well as with fibrosis, lobular and portal inflammation (range 0.31 ≤ R ≤ 42, p < 0.05). 19 MRCP + metrics correlated significantly with liver function tests (range 0.29 ≤ R ≤ 0.43, p < 0.05). GGT and MRCP + metrics were significantly higher in ASC compared to those with AIH. The best multivariable model for distinguishing ASC from AIH included total number of ducts and the sum of relative severity of both strictures and dilatations AUC: 0.91 (95% CI 0.78–1). Quantitative MRCP metrics are a good discriminator of ASC from AIH.

Evaluation of quantitative MRCP (MRCP+) for risk stratification of primary sclerosing cholangitis: comparison with morphological MRCP, MR elastography, and biochemical risk scores

OBJECTIVES

To study the association of MRCP+ parameters with biochemical scoring systems and MR elastography (MRE) in primary sclerosing cholangitis (PSC). To evaluate the incremental value of combining MRCP+ with morphological scores in associating with biochemical scores.

METHODS AND MATERIALS

MRI images, liver stiffness measurements by MRE, and biochemical testing of 65 patients with PSC that were retrospectively enrolled between January 2014 and December 2015 were obtained. MRCP+ was used to post-process MRCP images to obtain quantitative measurements of the bile ducts and biliary tree. Linear regression analysis was used to test the associations. Bootstrapping was used as a validation method.

RESULTS

The total number of segmental strictures had the strongest association with Mayo Risk Score (R² = 0.14), minimum stricture diameter had the highest association with Amsterdam Oxford Prognostic Index (R² = 0.12), and the percentage of duct nodes with width 0-3 mm had the strongest association with PSC Risk Estimate Tool (R² = 0.09). The presence of Ducts with medians > 9 mm had the highest association with MRE (R²= 0.21). The strength of association of MRCP+ to Mayo Risk Score was similar to ANALI2 and weaker than MRE (R² = 0.23, 0.24, 0.38 respectively). MRCP+ enhanced the association of ANALI 2 and MRE with the Mayo Risk Score.

CONCLUSIONS

MRCP+ demonstrated a significant association with biochemical scores and MRE. The association of MRCP+ with the biochemical scores was generally comparable to ANALI scores. MRCP+ enhanced the association of ANALI2 and MRE with the Mayo Risk Score.

KEY POINTS

• MRCP+ has the potential to act as a risk stratfier in PSC. • MRE outperformed MRCP+ for risk stratifcation. • Combination of MRCP+ with MRE and ANALI scores improved overall performace as risk stratifiers.

Primary sclerosing cholangitis-associated cholangiocarcinoma: special considerations and best practices

Introduction: Primary sclerosing cholangitis (PSC) is a rare, heterogenous, chronic cholestatic liver disease that causes fibro-inflammatory destruction of the intra- and/or extrahepatic bile ducts. The disease course may be variable, though in many cases it ultimately leads to biliary cirrhosis and its associated complications. PSC is also associated with malignancies, in particular cholangiocarcinoma (CCA), a dreaded neoplasm of the biliary tract with a poor prognosis. Risk stratification and surveillance for this malignancy are important components of the care of patients with PSC.Areas covered: In this review, we discuss important considerations in the clinical epidemiology, risk factors, diagnosis, and surveillance of PSC-associated CCA.Expert opinion: Despite growing awareness of PSC, high-quality evidence regarding the management of PSC and its associated risk of CCA remains limited. Early diagnosis of PSC-associated CCA remains difficult, and treatment options are limited, especially when diagnosed at later stages. The recent introduction of recommendations for CCA surveillance will likely improve outcomes, though an optimal surveillance approach has yet to be validated prospectively. Further research is needed in the development of high-accuracy (and noninvasive) surveillance and diagnostic tools that may facilitate earlier diagnosis of CCA and potential disease cure.

Prevalence and long-term outcome of sub-clinical primary sclerosing cholangitis in patients with ulcerative colitis

BACKGROUND

Primary sclerosing cholangitis (PSC) is closely associated with inflammatory bowel disease, particularly ulcerative colitis (UC), with an increased risk of biliary and colorectal malignancy. We sought to clarify the prevalence, characteristics and long-term outcome of sub-clinical PSC diagnosed by magnetic resonance cholangiogram (MRC) in patients with UC and normal liver biochemistry, with or without colorectal dysplasia (CRD).

METHODS

In this prospective case-control study, 70 patients with UC and normal liver function (51 extensive UC, 19 CRD), 28 healthy volunteers (negative controls) and 28 patients with PSC and cholestasis (positive controls) underwent MRC and blood evaluation. MRC scans were interpreted blindly by two radiologists who graded individually, the scans as definitive for PSC, possible for PSC or normal. Clinical outcome was assessed by blood monitoring, abdominal imaging and endoscopic surveillance.

RESULTS

7/51 (14%) with extensive UC and 4/19 (21%) with CRD had biliary abnormalities on MRC consistent with PSC. 7/11 (64%) with sub-clinical PSC had isolated intrahepatic duct involvement. Sub-clinical PSC was associated with advanced age (P = .04), non-smoking (P = .03), pANCA (P = .04), quiescent colitis (P = .02), absence of azathioprine (P = .04) and high-grade CRD (P = .03). Inter-observer (kappa = 0.88) and intra-observer (kappa = 0.96) agreement for MRC interpretation was high. No negative controls were assessed as definite PSC, 4/28 were considered on blinding as possible PSC. During follow-up of sub-clinical PSC (median 10.1(3.1-11.9) years), four patients developed abnormal liver biochemistry, two had radiological progression of PSC and seven developed malignancy, including two biliary and one colorectal carcinoma.

CONCLUSIONS

Prevalence of sub-clinical PSC appears high in patients with extensive UC and normal liver biochemistry, with or without CRD. Disease progression and malignancy were identified on long-term follow-up. MRC should be considered for all patients with extensive UC or CRD to stratify surveillance.

Cross-sectional imaging in patients with primary sclerosing cholangitis: Single time-point liver or spleen volume is associated with survival

AIM

To evaluate the association between single time-point quantitative liver and spleen volumes in patients with PSC and transplant-free survival, independent of Mayo risk score.

MATERIALS AND METHODS

This HIPAA-compliant retrospective study included 165 PSC patients in a hospital. Total (T), and lobar (right [R], left [L], and caudate [C]) liver volumes and spleen volume (S) were measured. Adverse outcome was identified as being on liver transplantation list, transplantation or death (outcome 1), and transplantation or death (outcome 2). Cox-regression was performed to assess the predictive value of volumetric parameters to predict transplant-free survival with and without Mayo risk score. Stratified analysis by Mayo risk score categories was performed to assess the discriminative value of volumes in the model. Prediction models were developed dependent of Mayo score, based on patients demographics, lab values and volumetric measures for both defined outcomes. Kaplan-Meier curves were depicted for different liver and spleen volumes. P value <0.05 was considered statistically significant.

RESULTS

In this cohort (age 43 ± 17 years; 59 % men) 51 % of patients had adverse outcome. Cox-regression analysis demonstrated statistically significant association between values of T, L, R, C, S, L/T, and C/T and outcome 1; and also statistically significant association between values C, S, and C/T and outcome 2. Prediction models included age, INR, total bilirubin, AST, variceal bleeding, S, and C for outcome 1 and age, INR, total bilirubin, AST, variceal bleeding, and S for outcome 2.

CONCLUSIONS

Based on our observational study, quantitative liver and spleen volumes may be associated with transplant-free survival in patients with PSC and may have the potential for predicting the outcome but this should be validated by randomized clinical trial studies.

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.

Magnetic resonance imaging features of small-duct primary sclerosing cholangitis

PURPOSE

To evaluate the biliary tree and hepatic parenchymal findings on magnetic resonance imaging (MRI) and magnetic resonance cholangiopancreatography (MRCP) in small-duct primary sclerosing cholangitis (SD-PSC).

METHODS

Thirty-nine patients with biopsy-proven primary sclerosing cholangitis (PSC) without any bile duct abnormality on MRCP (n = 15) or ERCP (n = 24) at the time of diagnosis were identified. Follow-up MRCP was available in 36/39 patients (12/15 Baseline MRCP group and 24 Baseline ERCP group). Two radiologists in consensus assessed the MRI/MRCP findings. The baseline MRI/MRCP of 15 SD-PSC patients was compared with MRI/MRCP of 15 normal healthy potential liver donors (Control group). Comparisons were made between SD-PSC patients and the Control group, and between baseline and follow-up MRI/MRCP findings in the SD-PSC patients.

RESULTS

In the 15 Baseline MRCP SD-PSC subjects, the biliary tree was normal with a trend of larger bile ducts compared to the Control group. Periductal enhancement (arterial phase: 70%, 7/10; delayed phase: 90%, 9/10), heterogeneous parenchymal signal on T2-weighted (53%, 8/15) and post contrast-enhanced images (70%, 7/10), and enlarged periportal lymph nodes (73%, 11/15) were frequently present in patients with SD-PSC. Eight (33%) of 24 SD-PSC patients who had normal MRCP at baseline MRCP or initial follow-up MRCP after normal baseline ERCP showed large-duct PSC (LD-PSC) features on follow-up and the 10-year cumulative incidence for progression to LD-PSC rate was 8.5%.

CONCLUSION

SD-PSC patients have a normal biliary tree but frequently have peribiliary enhancement, abnormal parenchymal signal intensity, and periportal lymphadenopathy. One-third shows progression to LD-PSC on follow-up.

Cholangiocarcinoma in patients with primary sclerosing cholangitis

PURPOSE OF REVIEW

Primary sclerosing cholangitis (PSC) is a rare cholestatic liver disease characterized by progressive fibroinflammatory destruction of the intrahepatic and/or extrahepatic bile ducts. It is associated with a significantly increased risk of malignancy, particularly cholangiocarcinoma (CCA). In this review, we discuss what is currently known about the epidemiology of and risk factors for CCA in PSC as well as recent advances in its prevention, diagnosis, and surveillance.

RECENT FINDINGS

An area of major focus has been finding novel biomarkers (in serum, bile, and urine) for CCA. With the advancement of computing power, metabolomic and proteomic approaches, among other methods, may provide enhanced capability for differentiating between benign and malignant bile duct disease. Another area of focus has been the approach to CCA surveillance in PSC; a recent study has found that CCA surveillance in patients with PSC is associated with improved outcomes, including increased survival, thus advocating for its importance.

SUMMARY

Despite ongoing advancements in the study of PSC-associated CCA, early diagnosis of CCA remains difficult, treatment options are limited, and prognosis is often consequently poor. Continued research in the development of high-accuracy diagnostic tools, novel biomarkers, and surveillance techniques may help to increase the likelihood of diagnosing CCA at earlier stages, when therapeutic options have the highest likelihood of resulting in cure.

Inter-reader agreement of interpretation of radiological course of bile duct changes between serial follow-up magnetic resonance imaging/3D magnetic resonance cholangiopancreatography of patients with primary sclerosing cholangitis

Objectives: Interpretation of MRI/MRCP in primary sclerosing cholangitis (PSC) at a single time point has low inter-reader agreement. Agreement of interpretation of the dynamic course of duct changes in follow-up MRI/MRCP is of clinical importance but remains unknown. Our aims are therefore to assess the inter-reader agreement of interpretation of the course of duct changes in PSC and investigate if elimination of 3 D MRCP affects inter-reader agreement.Materials and Methods: We studied 40 consecutive PSC-patients who underwent two liver MRI/MRCPs at two time points. Two readers independently evaluated the course of duct changes between the two time points in two imaging sets, one with and one without 3 D MRCP. The intraclass correlation coefficient (ICC) was calculated for evaluation of inter-reader and intra-reader agreement between the two time points and two imaging sets accordingly.Results: Inter-reader agreement of the interpretation of the course of duct changes between the two time points was poor (ICC up to 0.224). Elimination of 3 D MRCP neither improved inter-reader agreement which was again poor (ICC up to 0.26) nor did it change considerably the way readers interpret the course of ducts changes (ICC for intra-reader agreement between 0.809 and 0.978).Conclusions: Inter-reader agreement of the interpretation of radiological course of duct changes is poor in serial follow-up MRI/MRCP of PSC-patients. Elimination of 3 D MRCP does not increase inter-reader agreement but maintains an excellent intra-reader agreement for the interpretation of the dynamic course of bile duct changes.Key pointsInter-reader agreement of interpretation of radiological course of bile duct changes between serial follow-up MRI/MRCP examinations of patients with PSC is poor.Absence of 3D MRCP does not affect considerably the way readers interpret the radiological course of bile ducts changes.When MRCP is absent or of low quality, utilization of other sequences seems to be helpful as an alternative for bile duct evaluation.

Differentiating pediatric autoimmune liver diseases by quantitative magnetic resonance cholangiopancreatography

PURPOSE

Autoimmune liver diseases (AILD), including primary sclerosing cholangitis (PSC), autoimmune sclerosing cholangitis (ASC), and autoimmune hepatitis (AIH), have overlapping clinical features but distinct management strategies and outcomes. The purpose of this study was to assess the diagnostic performance of quantitative magnetic resonance cholangiopancreatography (MRCP) parameters for distinguishing PSC/ASC from AIH in children and young adults.

MATERIALS AND METHODS

This IRB-approved, cross-sectional study included participants from an institutional AILD registry that underwent baseline serum liver biochemistry testing and 3D fast spin-echo MRCP. The biliary tree was extracted and modeled from MRCP images using novel proprietary software (MRCP+ ™; Perspectum Diagnostics; Oxford, United Kingdom), and quantitative parameters were generated (e.g., biliary tree volume; number and length of bile ducts, strictures, and dilations; bile duct median/maximum diameters). Mann-Whitney U tests were performed to compare laboratory values and MRCP metrics between patient cohorts (clinical diagnosis of PSC/ASC versus AIH). Receiver operating characteristic (ROC) curves and multivariable logistic regression were used to assess diagnostic performance of serum biochemistry values and MRCP parameters for discriminating PSC/ASC from AIH.

RESULTS

Thirty percent (14/47) of MRCP exams failed post-processing due to motion artifact. The remaining 33 patients included 20 males and 13 females, with a mean age of 15.1 ± 3.9 years. Eighteen patients were assigned the clinical diagnosis of PSC or ASC and 15 of AIH. All but one quantitative MRCP parameter were significantly different between cohorts (p < 0.05) and predictive of diagnosis (ROC p < 0.05), including numbers of bile duct strictures (area under curve [AUC] = 0.86, p < 0.0001) and dilations (AUC = 0.87, p < 0.0001) and total length of dilated ducts (AUC = 0.89, p < 0.0001). Laboratory values were not significantly different between cohorts (p > 0.05). The best multivariable model for distinguishing PSC/ASC from AIH included total length of dilated ducts (odds ratio [OR], 1.08; 95% CI 1.02-1.14) and maximum left hepatic duct diameter (OR, 1.21; 95% CI 0.57-2.56) [AUC = 0.92].

CONCLUSION

Quantitative MRCP parameters provide good discrimination of PSC/ASC from AIH.

Simple Magnetic Resonance Scores Associate With Outcomes of Patients With Primary Sclerosing Cholangitis

BACKGROUND & AIMS

Primary sclerosing cholangitis (PSC) has a variable, often progressive, course. Magnetic resonance cholangiography (MRC) is used in the diagnosis of PSC. Magnetic resonance risk scoring systems, called Anali without and with gadolinium, are used to predict disease progression, determined by radiologic factors. We aimed to assess the prognostic value of Anali scores in patients with PSC and validate our findings in a separate cohort.

METHODS

We performed a retrospective study of patients with large-duct PSC (internal cohort, 119 patients in France; external cohort, 119 patients in Canada, Italy, and the United Kingdom). All the first-available MRC results were reviewed by 2 radiologists and the Anali scores were calculated as follows: Anali without gadolinium = (1× dilatation of intrahepatic bile ducts) + (2× dysmorphy) + (1× portal hypertension); Anali with gadolinium = (1× dysmorphy) + (1× parenchymal enhancement heterogeneity). The primary end point was survival without liver transplantation or cirrhosis decompensation. The prognostic value of Anali scores was assessed by Cox regression modeling.

RESULTS

During a total of 549 patient-years for the internal cohort and 497 patient-years for the external cohort, we recorded 2 and 8 liver transplantations, 4 and 3 liver-related deaths, and 26 and 25 cirrhosis decompensations, respectively. In the univariate analysis, factors associated with survival without liver transplantation or cirrhosis decompensation in the internal cohort were as follows: serum levels of bilirubin, aspartate aminotransferase, alanine aminotransferase, γ-glutamyl transferase, alkaline phosphatase, albumin, and Anali scores. Anali scores without and with gadolinium identified patients' survival without liver transplantation or cirrhosis decompensation with a c-statistic of 0.89 (95% CI, 0.84-0.95) and 0.75 (95% CI, 0.64-0.87), respectively. Independent prognostic factors identified by multivariate analysis were Anali scores and bilirubinemia. The prognostic value of Anali scores was confirmed in the external cohort.

CONCLUSIONS

In internal and external cohorts, we found that Anali scores, determined from MRC, were associated with outcomes of patients with PSC. These scores might be used as prognostic factors.

Predictive criteria of response to endoscopic treatment for severe strictures in primary sclerosing cholangitis

BACKGROUND

The aim of this study was to identify predictive criteria of improvement after endoscopic treatment (ET) for severe strictures of extrahepatic bile ducts in patients with primary sclerosing cholangitis (PSC).

METHODS

PSC patients who had at least one ET for severe stricture were included. Features of magnetic resonance cholangiography (MRC), performed before ET, were evaluated according to a standard model of interpretation, and a radiologic qualitative score of probability of improvement after ET was built. Score 3 (likely) was given in case of severe common bile duct (CBD) stricture with marked dilatation without severe strictures of upstream ducts, Score 1 (unlikely) was given in case of severe multiple strictures of secondary ducts without biliary dilatation and Score 2 (undeterminate) was given to an intermediate pattern. The response to ET was assessed at 2 months (T2-response) from the last ET and at 12 months (T12-response) from inclusion.

RESULTS

Thirty-one patients were included. All had severe stricture (reduction ≥ 75% of the diameter) of CBD and 50% had severe stricture of right and/or left hepatic duct (LHD) at MRC before ET. According to the qualitative score, 16 patients had Score 3, 7 had Score 1 and 9 had Score 2. T12-response was obtained in 50% of patients. In univariate analysis, short LHD strictures, bilirubin, transaminases, pruritus and Score 3 were associated with T12-response. Increased bilirubin and transaminases were independent predictive factors of T12-response (HR 24, 95% CI: 3.4-170.4, P = 0.001 and 23.8, 95% CI: 3.4-169.4, P = 0.002, respectively).

CONCLUSION

MRC, together with biochemical features, may contribute to identify the PSC patients who are likely to be improved after ET for severe strictures of extrahepatic bile ducts.

Longitudinal analysis of CA19-9 reveals individualised normal range and early changes before development of biliary tract cancer in patients with primary sclerosing cholangitis

BACKGROUND

Primary sclerosing cholangitis is associated with an increased risk of biliary tract cancer. Carbohydrate antigen 19-9 (CA19-9) can be used to screen for these malignancies.

AIM

To perform a longitudinal analysis of CA19-9 in patients with primary sclerosing cholangitis.

METHODS

We conducted a retrospective analysis of CA19-9 values in patients who had primary sclerosing cholangitis, with and without biliary malignancy. We calculated the index of individuality and reference change value in patients who were cancer-free. Long-term analysis of CA19-9 in cancer-free patients was performed and we assessed the change of CA19-9 prior to diagnosis of cancer.

RESULTS

We obtained 1818 CA19-9 values from 247 patients, including 32 with malignancy. Median CA19-9 in cancer-free individuals was 15.6 U/mL. The index of individuality was 0.37 and the reference change value was 46.23%. In cancer-free patients, no significant change in CA19-9 was observed at 1, 2, 5, 7, 10, 15, and 20 years after initial diagnosis of primary sclerosing cholangitis. In patients with biliary tract cancer, CA19-9 was higher at 3 months prior to diagnosis (P < 0.05) than at 6 months before diagnosis and was also higher than at 3 months prior to last follow-up in cancer-free patients (P < 0.05). In 92.9% of patients with biliary cancer, we found an increase in CA19-9 of >46.23% in the year prior to cancer diagnosis.

CONCLUSIONS

CA19-9 in patients with primary sclerosing cholangitis is highly individual, and the reference change value should be preferred to reference intervals. In this study, CA19-9 remained stable in patients who were cancer-free but increased early in those who developed biliary tract cancer. Regular CA19-9 measurement might improve early detection of these malignancies.

Evolving role of magnetic resonance techniques in primary sclerosing cholangitis

Development of non-invasive methods to risk-stratify patients and predict clinical endpoints have been identified as one of the key research priorities in primary sclerosing cholangitis (PSC). In addition to serum and histological biomarkers, there has been much recent interest in developing imaging biomarkers that can predict disease course and clinical outcomes in PSC. Magnetic resonance imaging/magnetic resonance cholangiopancreatography (MRI/MRCP) continue to play a central role in the diagnosis and follow-up of PSC patients. Magnetic resonance (MR) techniques have undergone significant advancement over the last three decades both in MR data acquisition and interpretation. The progression from a qualitative to quantitative approach in MR acquisition techniques and data interpretation, offers the opportunity for the development of objective and reproducible imaging biomarkers that can potentially be incorporated as an additional endpoint in clinical trials. This review article will discuss how the role of MR techniques have evolved over the last three decades from emerging as an alternative diagnostic tool to endoscopic retrograde cholangiopancreatography, to being instrumental in the ongoing search for imaging biomarker of disease stage, progression and prognosis in PSC.