Spatial Distribution of Pancreatic Stones in Chronic Pancreatitis.

OBJECTIVES: The aim of this study was to establish a standard to describe the spatial distribution of pancreatic stones in chronic pancreatitis (CP). METHODS: Two hundred forty-seven CP patients with pancreatic stones from June to December 2012 were enrolled. Two-dimensional images from coronal projection of 3-dimensional computed tomography images of pancreatic stones were gained. The number (n) of all stones and the geometric standard deviation (σ) of distances between the centroid of all stones and the centroids of every stone that represented the spatial distribution nonuniformity were calculated by Stone Reconstruction and Identification Programming System. RESULTS: The mean value of n and σ were 13.6 and 22.5; n > 13.6 and σ > 22.5 were determined as "multistones" and "nonuniform," respectively. Compared with alcoholic CP, idiopathic CP was less prone to multistones (odds ratio [OR], 0.310) and more prone to nonuniform (OR, 3.247). Pancreatic pseudocyst (OR, 2.211) in CP course was a risk factor of multistones, whereas diabetes mellitus in first-/second-/third-degree relatives (OR, 0.382) was a protective factor. Age at diagnosis of pancreatic stones (OR, 1.022) was a risk factor of nonuniformity. CONCLUSIONS: Compared with idiopathic CP, alcoholic CP patients were prone to more pancreatic stones that distribute more uniformly.

Analysis of metabolic characteristics in a rat model of chronic pancreatitis using high-resolution magic-angle spinning nuclear magnetic resonance spectroscopy.

Pathological and metabolic alterations co-exist and co-develop in the progression of chronic pancreatitis (CP). The aim of the present study was to investigate the metabolic characteristics and disease severity of a rat model of CP in order to determine associations in the observed pathology and the metabolites of CP using high-resolution magic-angle spinning nuclear magnetic resonance spectroscopy (HR-MAS NMR). Wistar rats (n=36) were randomly assigned into 6 groups (n=6 per group). CP was established by administering dibutyltin dichloride solution into the tail vein. After 0, 7, 14, 21, 28 and 35 days, the pancreatic tissues were collected for pathological scoring or for HR-MAS NMR. Correlation analyses between the major pathological scores and the integral areas of the major metabolites were determined. The most representative metabolites, aspartate, betaine and fatty acids, were identified as possessing the greatest discriminatory significance. The Spearman's rank correlation coefficients between the pathology and metabolites of the pancreatic tissues were as follows: Betaine and fibrosis, 0.454 (P=0.044); betaine and inflammatory cell infiltration, 0.716 (P=0.0001); aspartate and fibrosis, -0.768 (P=0.0001); aspartate and inflammatory cell infiltration, -0.394 (P=0.085); fatty acid and fibrosis, -0.764 (P=0.0001); and fatty acid and inflammatory cell infiltration, -0.619 (P=0.004). The metabolite betaine positively correlated with fibrosis and inflammatory cell infiltration in CP. In addition, aspartate negatively correlated with fibrosis, but exhibited no significant correlation with inflammatory cell infiltration. Furthermore, the presence of fatty acids negatively correlated with fibrosis and inflammatory cell infiltration in CP. HR-MAS NMR may be used to analyze metabolic characteristics in a rat model of different degrees of chronic pancreatitis.

Intravoxel incoherent motion MRI of the healthy pancreas: Monoexponential and biexponential apparent diffusion parameters of the normal head, body and tail.

BACKGROUND: To investigate the monoexponential and biexponential apparent diffusion parameters in different anatomical regions of the healthy pancreas using intravoxel incoherent motion (IVIM) diffusion weighted imaging (DWI). METHODS: Fifty-seven healthy volunteers (age, 45.0 ± 10.8 years) were recruited. DWI of the pancreas was performed with 9 b-values (0, 20, 50, 100, 200, 400, 600, 800, and 1000 s/mm(2) , respectively). The ADC was calculated for all b-values using linear regression yielding ADCtotal . The ADCb value of the monoexponential DWI, slow component of diffusion (ADCslow ), incoherent microcirculation (ADCfast ) and perfusion fraction (f) of the biexponential DWI were calculated for the pancreas head, body and tail. Dependency of the parameters on the anatomical regions was analyzed using Friedman test. RESULTS: All of the mean ADC400 , ADC600 , ADC800 , ADC1000 , ADCtotal and f values differed significantly among the anatomical regions with the lowest values were observed in the tail of pancreas (P < 0.05). The Friedman test results demonstrated a significant decline of the mean ADC values of the monoexponential DWI from b20 to b1000 for the three anatomical regions respectively (P < 0.001). CONCLUSION: Multi-b-value DWI derived quantitative parameters including ADC400 , ADC600 , ADC800 , ADC1000 , ADCtotal , and f differed significantly among the pancreatic head, body and tail, with the lowest values obtained in the tail.

High resolution diffusion weighted magnetic resonance imaging of the pancreas using reduced field of view single-shot echo-planar imaging at 3 T.

Diffusion weighted magnetic resonance imaging (DWI) has been mostly acquired using single-shot echo-planar imaging (ss EPI) to minimize motion induced artifacts. The spatial resolution, however, is inherently limited in ss EPI especially for abdominal imaging, even with the advances in parallel imaging. A novel method of reduced Field of View ss EPI (rFOV ss EPI) has achieved high resolution DWI in human carotid artery, spinal cord with reduced blurring and higher spatial resolution than conventional ss EPI, but it has not been used to pancreas imaging. In the work, comparisons between the full FOV ss-DW EPI and rFOV ss-DW EPI in image qualities and ADC values of pancreatic tumors and normal pancreatic tissues were performed to demonstrate the feasibility of pancreatic high resolution rFOV DWI. There were no significant differences in the mean ADC values between full FOV DWI and rFOV DWI for the 17 subjects using b=600s/mm(2) (P=0.962). However, subjective scores of image quality was significantly higher at rFOV ss DWI (P=0.008 and 0.000 for b-value=0s/mm(2) and 600s/mm(2) respectively). The spatial resolution of DWI for pancreas was increased by a factor of over 2.0 (from almost 3.0mm/pixel to 1.25mm/pixel) using rFOV ss EPI technique. Reduced FOV ss EPI can provide good DW images and is promising to benefit applications for pancreatic diseases.

Metabolic characteristics of acute necrotizing pancreatitis and chronic pancreatitis.

The etiology and pathogenesis of pancreatitis remains unclear. In the presence of pancreatic inflammation, metabolite abnormalities appear before transformation of tissue structure and changes in functions occur. Detection of abnormalities in metabolite levels facilitates a greater understanding of the pathophysiological events and aids in the early diagnosis of the disease. In this study, metabolic profiles from the pancreas of Wistar rats were examined using high-resolution proton magic angle spinning nuclear magnetic resonance (MAS NMR) spectroscopy to investigate the metabolite indicator(s) of acute necrotizing pancreatitis (ANP) and chronic pancreatitis (CP). The animals were divided into three groups: those with histologically confirmed ANP (n = 7), those with CP (n = 6) and a control group (n = 9). The processed NMR spectra were analyzed using principal component analysis (PCA) to extract characteristic metabolites of ANP and CP. Levels of leucine, isoleucine and valine were increased in the ANP group, whereas an opposite trend was observed in the CP group. Increases in phosphocholine, glycerophosphocholine and choline levels, and decreases in fatty acids, lactate, betaine and glycine levels were observed in both the ANP and CP groups. Additionally, the lipid content in the CP group was higher than that observed in the ANP group. An increase in taurine levels was observed only in the CP group. In conclusion, pancreatitis causes a disruption of the metabolism in the pancreas at a molecular level, with increased taurine levels being a potential metabolite indicator for those with CP.