Abdominal CT predictors of fibrosis in patients with chronic pancreatitis undergoing surgery

Value of Two-Dimensional Shear-Wave Elastography in Differentiating Pancreatic Steatosis From Pancreatic Fibrosis

OBJECTIVES

Pancreatic steatosis (PS) and pancreatic fibrosis (PF) both show increased pancreatic echogenicity on conventional B-mode ultrasound. In this study, we assessed the applicability of two-dimensional shear-wave elastography (2D-SWE) for their discrimination.

METHODS

We gathered data from 120 adults with valid 2D-SWE measurements, comprising 40 healthy individuals, 55 individuals diagnosed with PS via non-enhanced computed tomography (CT), and 25 patients clinically diagnosed with non-calcific chronic pancreatitis. The participants were divided into three groups: normal pancreas (NP), PS, and PF. pancreatic echogenicity, pancreatic stiffness, and CT values between groups were analyzed.

RESULTS

The 2D-SWE and CT values among the NP, PS, and PF groups all showed significant differences (P < .001). For the diagnosis of PS and PF using 2D-SWE, the area under the curve (AUC) values were 0.9100 and 0.9940, respectively, with optimal cut-off values of 5.7 kPa for predicting PS and 8.2 kPa for predicting PF.

CONCLUSIONS

The 2D-SWE technique enabled rapid and quantitative assessment of the hardness of hyperechoic pancreas visualized on conventional B-mode ultrasound, which holds certain value in distinguishing PS from PF.

Contrast-Enhanced Computed Tomography and Laboratory Parameters as Non-Invasive Diagnostic Markers of Pancreatic Fibrosis

Pancreatic fibrosis (PF) is a part of the pathogenesis in most pancreatic disorders and plays a crucial role in chronic pancreatitis development. The aim of our study was to investigate a relationship between PF grade and signs in resected pancreatic specimens, and the results of both multidetector computed tomography (MDCT) post-processing parameters and fibronectin (FN), hyaluronic acid (HA), matrix metalloproteinase (MMP)-1, and MMP-9 serum levels. The examination results of 74 patients were analyzed. The unenhanced pancreas density (UPD) value and contrast enhancement ratio (CER) showed statistically significant differences in groups with peri- and intralobular fibrosis grades, an integrative index of fibrosis, inflammation in pancreatic tissue, and pancreatic duct epithelium metaplasia, while the normalized contrast enhancement ratio in the venous phase (NCER VP) significantly differed with the perilobular fibrosis grade, integrative fibrosis index, and inflammation (p < 0.05). The blood FN level showed a weak positive correlation with the intralobular fibrosis grade (rho = 0.32, p = 0.008). The blood level of HA positively correlated with the presence of prominent and enlarged peripheral nerves (rho = 0.28, p = 0.02) and negatively correlated with the unenhanced pancreas density value (rho = -0.42, p = 0.0001). MMP-1 and MMP-9 values' intergroup analysis and correlation did not show any statistical significance. The UPD value, NCER VP, and CER, as well as blood levels of FN and HA, could be used in non-invasive PF diagnosis.

Tumor fibrosis correlates with the survival of patients with pancreatic adenocarcinoma and is predictable using clinicoradiological features

OBJECTIVES

To evaluate the prognostic value of fibrosis for patients with pancreatic adenocarcinoma (PDAC) and preoperatively predict fibrosis using clinicoradiological features. Tumor fibrosis plays an important role in the chemoresistance of PDAC. However, the prognostic value of tumor fibrosis remains contradiction and accurate prediction of tumor fibrosis is required.

METHODS

The study included 131 patients with PDAC who underwent first-line surgery. The prognostic value of fibrosis and rounded cutoff fibrosis points for median overall survival (OS) and disease-free survival (DFS) were determined using Cox regression and receiver operating characteristic (ROC) analyses. Then the whole cohort was randomly divided into training (n = 88) and validation (n = 43) sets. Binary logistic regression analysis was performed to select independent risk factors for fibrosis in the training set, and a nomogram was constructed. Nomogram performance was assessed using a calibration curve and decision curve analysis (DCA).

RESULTS

Hazard ratios of fibrosis for OS and DFS were 1.121 (95% confidence interval [CI]: 1.082-1.161) and 1.110 (95% CI: 1.067-1.155). ROC analysis identified 40% as the rounded cutoff fibrosis point for median OS and DFS. Tumor diameter, carbohydrate antigen 19-9 level, and peripancreatic tumor infiltration were independent risk factors; areas under the nomogram curve were 0.810 and 0.804 in the training and validation sets, respectively. The calibration curve indicated good agreement of the nomogram, and DCA demonstrated good clinical usefulness.

CONCLUSIONS

Tumor fibrosis was associated with poor OS and DFS in patients with PDAC. The nomogram incorporating clinicoradiological features was useful for preoperatively predicting tumor fibrosis.

KEY POINTS

• Tumor fibrosis is correlated with poor prognosis in patients with pancreatic adenocarcinoma. • Tumor fibrosis can be categorized according to its association with overall survival and disease-free survival. • A nomogram incorporating carbohydrate antigen 19-9 level, tumor diameter, and peripancreatic tumor infiltration is useful for preoperatively predicting tumor fibrosis.

Multi-frequency magnetic resonance elastography of the pancreas: measurement reproducibility and variance among healthy volunteers

Background

Patients with chronic pancreatitis often have irreversible pancreatic insufficiency before a clinical diagnosis. Pancreatic cancer is a fatal malignant tumor in the advanced stages. Patients having high risk of pancreatic diseases must be screened early to obtain better outcomes using new imaging modalities. Therefore, this study aimed to investigate the reproducibility of tomoelastography measurements for assessing pancreatic stiffness and fluidity and the variance among healthy volunteers.

Methods

Forty-seven healthy volunteers were prospectively enrolled and underwent two tomoelastography examinations at a mean interval of 7 days. Two radiologists blindly and independently measured the pancreatic stiffness and fluidity at the first examination to determine the reproducibility between readers. One radiologist measured the adjacent pancreatic slice at the first examination to determine the reproducibility among slices and measured the pancreas at the second examination to determine short-term repeatability. The stiffness and fluidity of the pancreatic head, body, and tail were compared to determine anatomical differences. The pancreatic stiffness and fluidity were compared based on sex, age, and body mass index (BMI).

Results

Bland–Altman analyses (all P > 0.05) and intraclass correlation coefficients (all >0.9) indicated near perfect reproducibility among readers, slices, and examinations at short intervals. Neither stiffness (P = 0.477) nor fluidity (P = 0.368) differed among the pancreatic anatomical regions. The mean pancreatic stiffness was 1.45 ± 0.09 m/s; the mean pancreatic fluidity was 0.83 ± 0.06 rad. Stiffness and fluidity did not differ by sex, age, or BMI.

Conclusion

Tomoelastography is a promising and reproducible tool for assessing pancreatic stiffness and fluidity in healthy volunteers.

[Effect of morphological state of pancreatic parenchyma on the long-term outcome of surgery for chronic pancreatitis]

OBJECTIVE

To determine the effect of baseline morphological state of the pancreas on the long-term outcomes of duodenum-preserving pancreatic head resection (DPPHR).

MATERIAL AND METHODS

The study included 104 patients with chronic pancreatitis (CP), who underwent DPPHR in 2014-2019. Pain syndrome, exocrine and endocrine pancreatic insufficiency and quality of life (QoL) were assessed in long-term postoperative period. Patients were stratified depending on CT enhancement of pancreatic parenchyma as an indicator of fibrosis and amount of preserved acinar cells in resected pancreatic tissue.

RESULTS. S

Ignificant relief of pain syndrome in long-term period was observed in patients with higher density of pancreatic tissue in venous phase of CT compared to delayed phase. Moreover, these patients needed less additional enzyme intake and had higher QoL. Exocrine insufficiency depended on the number of preserved acinar cells. The percentage of preserved acinar cells also affects the QoL of patients with CP. There were no correlations between endocrine insufficiency and CT-findings, as well as the number of preserved acinar cells.

CONCLUSION

Higher CT-density of pancreatic parenchyma in venous phase indicates a lesser degree of fibrosis. It is a favorable prognostic factor for postoperative pain relief and preservation of exocrine function. The percentage of preserved acinar cells in the resected pancreatic tissue is a reliable predictor of exocrine insufficiency.

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

PURPOSE

There is an unmet need for new systems with quantitative pancreatic imaging assessments to support better diagnosis and understand development of chronic pancreatitis (CP). The aims were to present such an approach for assessment of imaging features in CP, to apply this system in a multi-center cohort of CP patients (feasibility study), and to report inter-reader agreement between expert radiologists (validation study).

METHODS

The feasibility study included pancreatic computed tomography (CT) or magnetic resonance imaging (MRI) from 496 patients with definitive CP in the Scandinavian Baltic Pancreatic Club (SBPC) database. Images were assessed according to the new SBPC imaging system (quantitative assessments of ductal and parenchymal features). Inter-reader agreement of reported imaging parameters was investigated for 80 CT and 80 MRI examinations by two expert radiologists.

RESULTS

Reporting of the imaging features into the imaging system was deemed feasible for > 80% of CT and > 90% of MRI examinations. Quantitative assessments of main pancreatic duct diameters, presence/number/diameter of calcifications, and gland diameters had high levels of inter-reader agreement with κ-values of 0.75-0.87 and intraclass correlation coefficients of 0.74-0.97. The more subjective assessments, e.g., irregular main pancreatic duct and dilated side-ducts, had poor to moderate agreement with κ-values of 0.03-0.44.

CONCLUSION

The presented system provides a feasible mean for systematic assessment of CP imaging features. Imaging parameters based on quantitative assessment, as opposed to subjective assessments, have better reproducibility and should be preferred in the development of new grading systems for understanding pathophysiology and disease progression in CP.

Cross-sectional imaging-based severity scoring of chronic pancreatitis: why it is necessary and how it can be done

Chronic pancreatitis (CP) remains a diagnostic challenge as clinical symptoms are non-specific, histopathological appearances are varied and pathogenesis remains incompletely understood. Multiple classifications and grading systems have been proposed for CP, but none leverage the full capabilities of cross-sectional imaging modalities and are not widely accepted or validated. CT and MRI/MRCP are useful in identifying a wide spectrum of histopathological changes in CP and can also assess exocrine reserve of pancreas. Advanced MRI techniques such as T1 mapping and extracellular volume fraction can potentially identify early CP. Cross-sectional imaging-based severity scoring can quantify CP disease burden and may have positive implications for clinicians and researchers. In this review, we discuss the need for cross-sectional imaging-based severity scoring for CP, role of CT, and MRI/MRCP in assessment of CP and how these modalities can be used to obtain severity scoring for CP. We summarize relevant information from recently published CT and MRI/MRCP reporting standards for CP, and from international guidelines for cross-sectional imaging and severity scoring for CP.

Pancreatic Fibrosis and Chronic Pancreatitis: Mini-Review of Non-Histologic Diagnosis for Clinical Applications

Pancreatic fibrosis is the dominant reversible pathological change and diagnostic factor in early chronic pancreatitis, defined by a mechanistic approach proposed in 2016. Main guidelines for chronic pancreatitis were published by the American Pancreas Association in 2014, the Japanese Society of Gastroenterology in 2015, and United European Gastroenterology in 2017. All three sets of guidelines mentioned that the staging of chronic pancreatitis is important but challenging. There are various image modalities for the non-histologic diagnosis of pancreatic fibrosis: (1) shear wave elastography, such as an acoustic radiation force impulse with a cut-off value of 1.4 m/s; (2) strain elastography using grades of strain; (3) endoscopic ultrasonography using the Rosemont criteria or endoscopic ultrasound criteria for early chronic pancreatitis proposed by the Japan Pancreas Society; (4) computed tomography using the Hounsfield scale or number of micro-calcifications; and (5) magnetic resonance imaging using the apparent diffusion coefficient and the T1w flash and T2w HASTE sequences. The clinical applications are to (1) evaluate pancreatic tumors and inflammatory disease; (2) monitor dyspepsia with early chronic pancreatitis; (3) monitor individuals with a high risk of pancreatic cancer; (4) analyze a fatty pancreas with fibrosis; (5) predict a fistula after pancreatic surgery; and (6) predict outcomes for chronic pancreatitis or pancreatic cancer. The selection of tools will be dependent on the clinical scenario. Conclusion: There are various modalities for the non-histologic diagnosis of pancreatic fibrosis. The selection of the optimal device will be dependent on the clinical scenario.

Imaging in chronic pancreatitis: State of the art review

Chronic pancreatitis (CP) is an important gastrointestinal cause of morbidity worldwide. It can severely impair the quality of life besides life-threatening acute and long-term complications. Pain and pancreatic exocrine insufficiency (leading to malnutrition) impact the quality of life. Acute complications include pseudocysts, pancreatic ascites, and vascular complications. Long-term complications are diabetes mellitus and pancreatic cancer. Early diagnosis of CP is crucial to alter the natural course of the disease. However, majority of the cases are diagnosed in the advanced stage. The role of various imaging techniques in the diagnosis of CP is discussed in this review.

Jejunal response to secretin is independent of the pancreatic response in secretin-enhanced magnetic resonance cholangiopancreatography

PURPOSE

To investigate whether jejunal secretions are independent of the pancreatic response to secretin in secretin-enhanced Magnetic Resonance Cholangiopancreatography (s-MRCP) examination of subjects with and without chronic pancreatitis (CP).

METHODS

Patients were identified through a search of s-MRCP examinations performed between 2014-2016 (n = 513) as well as the multidisciplinary pancreatitis clinic registry (n = 586). Fifty cases with CP (based on M-ANNHEIM criteria) and 50 matched controls were selected. Signal intensity changes after secretin administration (˜1-5 min' post-secretin response) in three locations were assessed: second portion of the duodenum (D2), third/fourth portions of the duodenum (D3-4), and the jejunum. The post-secretin response was compared between (cases vs. controls) and within the study groups.

RESULTS

There was a significantly lower 1-5 min' post-secretin response among CP patients in D2 (all p-values <0.01). However, no significant difference in 1-5 min' post-secretin response was detected in the jejunum. Minute-by-minute analysis of the post-secretin response showed a significant increase up to the 5th minute only in D2 of the control group. The post-secretin response in the jejunum was significant after 1 min but was similar among patients with CP and controls. CP was a significant determinant of post-secretin response in D2 but not in the jejunum.

CONCLUSIONS

Early post-secretin response at jejunum is independent of the pancreatic response that can be detected at D2, and should not be misinterpreted as a rapid pancreatic response. Therefore, pancreatic function on s-MRCP should be assessed by the presence of fluid in D2 and not jejunum.

Quantification of parenchymal calcifications in chronic pancreatitis: relation to atrophy, ductal changes, fibrosis and clinical parameters

OBJECTIVES

Parenchymal calcifications are considered a hallmark finding of chronic pancreatitis (CP), but little is known about its relation to the clinical presentation and other morphological features such as atrophy, fibrosis and ductal changes. The aim was to quantify the number and maximal size of parenchymal calcifications assessed on computed tomography (CT) and to explore the association with other CT and magnetic resonance imaging (MRI)-based pancreatic features and clinical parameters.

METHODS

A well-characterised cohort of 54 CP patients was included. CT measurements included number and size of parenchymal calcifications, gland diameter and ductal diameter. MRI measurements included gland volume, ductal diameter, fibrosis (diffusion) and fatty infiltration (Dixon). Clinical parameters included body mass index (BMI), CP duration and aetiology, M-ANNHEIM clinical stage, tobacco use, alcohol consumption, the presence of diabetes, faecal elastase, clinical pain score and quality of life.

RESULTS

There were no correlations between the number and size of parenchymal calcifications and any of the other morphological CT and MRI parameters (all p > .05), except for larger size of calcifications in patients with high number of calcifications (p < .001). The number of parenchymal calcifications was negatively correlated with BMI (r = -0.35, p = .0088). The number and size of parenchymal calcifications did not correlate with any of the other clinical parameters (all p > .2).

CONCLUSION

Our findings could indicate the existence of parenchymal calcifications as an independent pathophysiological process involved in the development of CP. Translational impact: Quantifications of calcifications could, in combination with other imaging biomarkers, be a useful imaging marker relevant for characterising CP.

Surgical approaches to chronic pancreatitis: indications and imaging findings

Chronic pancreatitis (CP) is an irreversible, inflammatory process characterized by progressive fibrosis of the pancreas that can result in abdominal pain, exocrine insufficiency, and diabetes. Inadequate pain relief using medical and/or endoscopic therapies is an indication for surgery. The surgical management of CP is centered around three main operations including pancreaticoduodenectomy (PD), duodenum-preserving pancreatic head resection (DPPHR) and drainage procedures, and total pancreatectomy with islet autotransplantation (TPIAT). PD is the method of choice when there is a high suspicion for malignancy. Combined drainage and resection procedures are associated with pain relief, higher quality of life, and superior short-term and long-term survival in comparison with the PD. TPIAT is a reemerging treatment that may be promising in subjects with intractable pain and impaired quality of life. Imaging examinations have an extensive role in pre-operative and post-operative evaluation of CP patients. Pre-operative advanced imaging examinations including CT and MRI can detect hallmarks of CP such as calcifications, pancreatic duct dilatation, chronic pseudocysts, focal pancreatic enlargement, and biliary ductal dilatation. Post-operative findings may include periportal hepatic edema, pneumobilia, perivascular cuffing and mild pancreatic duct dilation. Imaging can also be useful in the detection of post-operative complications including obstructions, anastomotic leaks, and vascular lesions. Imaging helps identify unique post-operative findings associated with TPIAT and may aid in predicting viability and function of the transplanted islet cells. In this review, we explore surgical indications as well as pre-operative and post-operative imaging findings associated with surgical options that are typically performed for CP patients.

Clinical chronic pancreatitis

PURPOSE OF REVIEW

To summarize observations in clinical chronic pancreatitis in the past year.

RECENT FINDINGS

A predisposing genetic mutation was identified in 67% of cases of pediatric chronic pancreatitis. A novel susceptibility gene involving a hybrid allele is associated with idiopathic chronic pancreatitis. ABO blood type B and FUT2 nonsecretor status is associated with asymptomatic hyperlipasemia and chronic pancreatitis. Alcohol consumption impairs cystic fibrosis transmembrane conductance regulator (CFTR) activity leading to decreased bicarbonate secretion and patients with susceptible CFTR mutations can develop clinical pancreatitis. Computed tomography imaging findings in chronic pancreatitis correlate poorly with pain patterns. Endoscopic ultrasound features correlate poorly with fibrosis. Circulating epithelial cells are present in chronic pancreatitis patients but not healthy volunteers. Surgery is superior to endoscopic treatment in providing durable pain relief (>5 years). Repetitive pancreatic duct stent placements and chronic narcotic use are preoperative predictors of poor outcome after total pancreatectomy with islet cell auto transplantation.

SUMMARY

Novel genetic mutations for idiopathic chronic pancreatitis are being identified. Alcohol impairs CFTR activity and may explain a mechanism for pancreatitis. Current imaging modalities correlate poorly with clinical pain presentation and fibrosis in chronic pancreatitis. Novel imaging modalities are needed. As total pancreatectomy with islet cell auto transplantation grows, rigorous outcomes analysis is needed to drive patient selection.