Systematic approach for assessment of imaging features in chronic pancreatitis: a feasibility and validation study from the Scandinavian Baltic Pancreatic Club (SBPC) database

Inter- and intra-observer variability of computed tomography-based parenchymal- and ductal diameters in chronic pancreatitis: a multi-observer international study

PURPOSE

The need for incorporation of quantitative imaging biomarkers of pancreatic parenchymal and ductal structures has been highlighted in recent proposals for new scoring systems in chronic pancreatitis (CP). To quantify inter- and intra-observer variability in CT-based measurements of ductal- and gland diameters in CP patients.

MATERIALS AND METHODS

Prospectively acquired pancreatic CT examinations from 50 CP patients were reviewed by 12 radiologists and four pancreatologists from 10 institutions. Assessment entailed measuring maximum diameter in the axial plane of four structures: (1) pancreatic head (PDhead), (2) pancreatic body (PDbody), (3) main pancreatic duct in the pancreatic head (MPDhead), and (4) body (MPDbody). Agreement was assessed by the 95% limits of agreement with the mean (LOAM), representing how much a single measurement for a specific subject may plausibly deviate from the mean of all measurements on the specific subject. Bland-Altman limits of agreement (LoA) were generated for intra-observer pairs.

RESULTS

The 16 observers completed 6400 caliper placements comprising a first and second measurement session. The widest inter-observer LOAM was seen with PDhead (± 9.1 mm), followed by PDbody (± 5.1 mm), MPDhead (± 3.2 mm), and MPDbody (± 2.6 mm), whereas the mean intra-observer LoA width was ± 7.3, ± 5.1, ± 3.7, and ± 2.4 mm, respectively.

CONCLUSION

Substantial intra- and inter-observer variability was observed in pancreatic two-point measurements. This was especially pronounced for parenchymal and duct diameters of the pancreatic head. These findings challenge the implementation of two-point measurements as the foundation for quantitative imaging scoring systems in CP.

Clinical Course of Medically Managed Patients With Large and Small Duct Chronic Pancreatitis

INTRODUCTION

Pancreatic duct obstruction is the primary indication for endoscopic and/or surgical therapy in patients with chronic pancreatitis (CP). However, the clinical course of medically managed patients in relation to pancreatic duct obstruction is largely unknown.

METHODS

This was a retrospective cohort study of medically managed patients with CP. We classified patients based on pancreatic duct obstruction from a stricture or stone using cross-sectional imaging (i.e., large vs small duct CP). We compared prevalence of diabetes and exocrine insufficiency (EPI) between subgroups at inclusion and investigated risk of new-onset diabetes, EPI, and all-cause mortality over a follow-up period of 5 years. Changes in pancreatic morphology were studied in patients who underwent follow-up imaging.

RESULTS

A total of 198 patients (mean age 58 ± 12 years, 70% male, 60% alcoholic etiology, 38% large duct CP) were evaluated. At inclusion, patients with large vs small duct CP had a higher prevalence of both diabetes (43% vs 24%, P = 0.004) and EPI (47% vs 28%, P = 0.007). There was an increased risk of new-onset EPI in patients with large duct CP (hazard ratio 1.72; 95% confidence interval [1.05-2.80], P = 0.031) and higher rates of pancreatic atrophy ( P < 0.001). No differences between groups were observed for new-onset diabetes and all-cause mortality. Conversion from small to large duct CP or vice versa during follow-up was observed in 14% of patients.

DISCUSSION

In a medically managed cohort of patients, large duct CP was associated with increased risk of EPI and pancreatic atrophy compared with small duct CP.

Interobserver Agreement for CT and MRI Findings of Chronic Pancreatitis in Children: A Multicenter Ancillary Study Under the INSPPIRE Consortium

BACKGROUND. Imaging findings represent key criteria for diagnosing chronic pancreatitis in children. Understanding radiologists' agreement for imaging findings is critical to standardizing and optimizing diagnostic criteria. OBJECTIVE. The purpose of this study is to evaluate the interobserver agreement among experienced pediatric radiologists for subjective, quantitative, and semiquantitative imaging findings of chronic pancreatitis in children. METHODS. In this retrospective study, CT or MRI examinations performed in children with chronic pancreatitis were submitted by six sites participating in the INSPPIRE (International Study Group of Pediatric Pancreatitis: In Search for a Cure) Consortium. One pediatric radiologist from each of the six sites reviewed examinations; three of the radiologists independently reviewed all CT examinations, and the other three radiologists independently reviewed all MRI examinations. Reviewers recorded 13 categoric imaging findings of chronic pancreatitis and measured pancreas thickness and pancreatic duct diameter. Agreement was assessed using kappa coefficients for the categoric variables and intraclass correlation coefficients (ICCs) for the continuous variables. RESULTS. A total of 76 CT and 80 MRI examinations performed in 110 children (65 girls and 45 boys; mean age, 11.3 ± 4.6 [SD] years) were reviewed. For CT, kappa coefficients for categoric findings ranged from -0.01 to 0.81, with relatively high kappa coefficients noted for parenchymal calcifications (κ = 0.81), main pancreatic duct dilatation (κ = 0.63), and atrophy (κ = 0.52). ICCs for parenchymal thickness measurements ranged from 0.57 in the pancreas head to 0.80 in the body and tail. The ICC for duct diameter was 0.85. For MRI, kappa coefficients for categoric findings ranged from -0.01 to 0.74, with relatively high kappa coefficients noted for main duct irregularity (κ = 0.74), side branch dilatation (κ = 0.70), number of dilated side branches (κ = 0.65), and main duct dilatation (κ = 0.64); kappa coefficient for atrophy was 0.52. ICCs for parenchymal thickness measurements ranged from 0.53 for the neck and body individually to 0.68 in the tail. ICC for duct diameter was 0.77. CONCLUSION. Interobserver agreement was fair to moderate for most CT and MRI findings of chronic pancreatitis in children. CLINICAL IMPACT. This study highlights challenges for the imaging diagnosis of pediatric chronic pancreatitis. Standardized and/or objective criteria are needed given the importance of imaging in diagnosis.

Structural imaging findings are related to clinical complications in chronic pancreatitis

BACKGROUND/OBJECTIVES

Structural pancreatic changes and complications related to chronic pancreatitis are well described, but little is known about their relationship. We aimed to explore the associations between pancreatic morphology and clinical complications in a large chronic pancreatitis cohort.

METHODS

The Scandinavian Baltic Pancreatic Club database collects registrations on patients with definite or probable chronic pancreatitis according to the M-ANNHEIM diagnostic criteria. In this cross-sectional study, we used multivariate logistic regression analyses to evaluate whether imaging-based structural pancreatic changes were associated with common clinical complications. We adjusted for sex, age, disease duration, current alcohol abuse and current smoking.

RESULTS

We included 742 patients with a mean age of 55 years. Among these, 68% were males, 69% had pancreatic exocrine insufficiency, 35% had diabetes, 12% were underweighted and 68% reported abdominal pain. Main pancreatic duct obstruction, severe (i.e. more than 14) calcifications, pancreatic atrophy and parenchymal changes throughout the entire pancreas (continuous organ involvement) were positively associated with pancreatic exocrine insufficiency. Continuous organ involvement and pseudocysts were positively and negatively associated with diabetes, respectively. Pancreatic atrophy and severe calcifications were positively associated with underweight, and severe calcifications were negatively associated with pain.

CONCLUSIONS

This study shows independent associations between distinct structural changes on pancreatic imaging and clinical complications in chronic pancreatitis. Pancreatic atrophy, severe calcifications and continuous organ involvement may be of particular clinical relevance, and these findings should motivate monitoring of pancreatic function and nutritional status.

Main Duct Thresholds for Malignancy Are Different in Intraductal Papillary Mucinous Neoplasms of the Pancreatic Head and Body-Tail

BACKGROUND & AIMS

The risk of malignancy is uncertain for intraductal papillary mucinous neoplasms (IPMNs) with main pancreatic duct (MPD) of 5-9 mm. No study has correlated MPD size and malignancy considering the anatomic site of the gland (head versus body-tail). Our aim was to analyze the significance of MPD in pancreatic head/body-tail as a predictor of malignancy in main-duct/mixed IPMNs.

METHODS

Retrospective analysis of resected patients between 2009-2018 was performed. Malignancy was defined as high-grade dysplasia and invasive carcinoma. MPD diameter was measured with magnetic resonance imaging. Receiver operating characteristic curve (ROC) analysis was utilized to identify optimal MPD cut-off for malignancy. Independent predictors of malignancy were searched.

RESULTS

Malignancy was detected in 74% of 312 identified patients. 213 patients (68.3%) had IPMNs of the pancreatic head and 99 (31.7%) of the body-tail. ROC analysis identified 9 and 7 mm as the optimal MPD cut-offs for malignancy in IPMNs of head and body-tail of the pancreas, respectively. Multivariate analysis confirmed that MPD ≥9 mm (pancreatic head) and ≥7 mm (body-tail) were independent predictors of malignancy along with macroscopic solid components, positive cytology and elevated CA 19-9. The risk of malignancy was low for IPMNs with MPD ≤8 mm (pancreatic head) or ≤6 mm (pancreatic body-tail) unless high-risk stigmata or multiple worrisome features were present.

CONCLUSIONS

Different thresholds of MPD dilation are associated with malignancy in IPMNs of the head and body-tail of the pancreas. The risk of malignancy for IPMNs with MPD ≤8 mm (pancreatic head) or ≤6 mm (pancreatic body-tail) lacking high-risk stigmata or multiple worrisome features is low.

T1 relaxation times and MR elastography-derived stiffness: new potential imaging biomarkers for the assessment of chronic pancreatitis

PURPOSE

Non-invasive imaging methods to detect morphological changes of the pancreas in patients with mild chronic pancreatitis (CP) are needed. This study aimed to compare magnetic resonance imaging-based parameters, pancreatic volume, T1 mapping, magnetic resonance elastography (MRE), and proton density fat fraction between CP patients and controls, and determine the diagnostic performance for diagnosing different stages of CP.

METHODS

Nineteen patients with mild CP (Cambridge grade 2 or less or recurring acute pancreatitis; n = 19), 30 with moderate/severe CP (Cambridge grade 3 and 4), and 35 healthy controls underwent pancreatic magnetic resonance imaging to assess the above mentioned magnetic resonance imaging-based parameters. The diagnostic performance of each parameter for detecting any mild and moderate/severe CP was determined using receiver operating characteristic analysis.

RESULTS

Pancreatic volume, T1 relaxation times, MRE-derived stiffness, and proton density fat fraction differed significantly between patients with mild CP, moderate/severe CP, and healthy controls (all p < 0.05). T1 mapping and MRE showed a very high diagnostic performance for distinguishing the mild CP group from the control group (T1 mapping: receiver operating characteristic area under the curve (ROC-AUC): 0.94; sensitivity: 84%; specificity: 91%, MRE: ROC-AUC: 0.93; sensitivity: 89%; specificity: 94%). T1 mapping and MRE also had the highest performance for diagnosing the presence of any CP from the control group (ROC-AUCs of 0.98 and 0.97, respectively).

CONCLUSION

Quantitative assessments of T1 relaxation time and MRE-derived stiffness had high performance in detecting mild CP and could probably reflect the early fibrotic changes in CP.

Aetiological risk factors are associated with distinct imaging findings in patients with chronic pancreatitis: A study of 959 cases from the Scandinavian Baltic Pancreatic Club (SBPC) imaging database

OBJECTIVES

The relation between aetiology and structural changes of the pancreas in patients with chronic pancreatitis (CP) is not fully understood. Earlier studies are limited by focusing on selected factors in studies of limited sample size. We aimed to use a large dataset to explore associations between aetiology and pancreatic morphology in CP.

METHODS

Subjects with definite or probable CP according to the M-ANNHEIM diagnostic criteria were included in this multicentre cross-sectional observational study and assessed using a standardized and validated CP imaging system. We performed multivariate logistic regression to analyse if aetiological factors adjusted for covariates were independently associated with morphological pancreatic features.

RESULTS

We included 959 patients (66% males). Mean (SD) age was 55 (14) years. Pancreatic structural changes were found in 94% of the subjects: 67% had calcifications, 59% main pancreatic duct dilatation, 33% pseudo-cysts and 22% pancreatic atrophy. Alcohol abuse was independently associated with pancreatic calcifications (odds ratio (OR, [95% CI]); 1.61, [1.09, 2.37]) and focal acute pancreatitis (OR; 2.13, [1.27, 3.56]), whereas smoking was independently associated with more severe calcifications (OR; 2.09, [1.34, 3.27]) and involvement of the whole gland (OR; 2.29, [1.61, 3.28]). Disease duration was positively associated with calcifications (OR; (per year) 1.05 [1.02, 1.08]) and pancreatic atrophy (OR; 1.05 [1.02, 1.08]) and negatively associated with focal acute pancreatitis (OR 0.91, [0.87, 0.95] and pseudo cysts (OR; 0.96, [0.93, 0.98]).

CONCLUSION

In this large-scale study, etiological risk factors and disease duration in CP were independently associated with specific structural pancreatic imaging changes.

Diagnostic Accuracy of Computed Tomography Scores in Chronic Pancreatitis

OBJECTIVES

Computed tomography (CT) is the most commonly used imaging modality when diagnosing chronic pancreatitis (CP). We aimed to evaluate the diagnostic accuracy of CT scores for diagnosing CP.

METHODS

One hundred eighteen patients were retrospectively included from an observational cohort study that comprised patients referred because of suspected CP. Patients were categorized as CP or non-CP using a modified Mayo score based on biochemistry, clinical presentation, and findings on endoscopic ultrasound and/or transabdominal ultrasound. The CT scans were scored according to the modified Cambridge classification and the unweighted CT score. Diagnostic performance indices were calculated using the modified Mayo score as reference standard.

RESULTS

Seventy-six of the 118 patients fulfilled the CP diagnostic criteria (Mayo score ≥4). The modified Cambridge classification and the unweighted CT score yielded sensitivities of 63% and 67% and specificities of 91% and 91%, respectively, and similar areas under the receiver operating characteristic curves (95% confidence interval) of 0.79 (0.71-0.88)/0.81 (0.73-0.89), respectively (P, not significant).

CONCLUSIONS

Both CT scores had similar, moderate accuracies for diagnosing CP. The limitation in diagnostic accuracy makes CT ineligible as a single method to diagnose CP, supporting that the diagnostic process for CP needs to incorporate other imaging methods and/or markers for better diagnostics.