DCE‐MRI in experimental chronic pancreatitis

Abstract

To assess pancreatic perfusion in experimental chronic pancreatitis (CP) by dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI). DCE MRI on a 1.5 T MR scanner was performed on 21 piglets with the ligation of pancreatic duct. They were divided into four groups based on pathology, including seven normal pigs and seven, three and four piglets with grade I, II and III CP, respectively. The signal intensity measured in the pancreatic body on DCE MRI was plotted against time to create a signal intensity-time (SI-T) curve for each piglet. The steepest slope (SS), time-to-peak (TTP) and peak enhancement ratio (PER) of the SI-T curve were noted. In the four groups, on the SI-T curve derived from DCE MRI, the SS was, respectively, 10. and TTP (r ¼ 0.538, p ¼ 0.012) of the SI-T curve was correlated to the severity of CP, respectively. DCE MRI has a potential to diagnose moderate to advanced CP. The SS and TTP of the SI-T curve were correlated to the severity of CP.

Spleen Dynamic Contrast-Enhanced Magnetic Resonance Imaging as a New Method for Staging Liver Fibrosis in a Piglet Model

“…Care was taken to exclude spleen hilar blood vessels when drawing the ROIs within the spleen (Figure 1A). Signal intensity time curve (STC, Figure 1B) was derived, and spleen DCE-MRI parameters including time to peak (TTP, Figure 1C), positive enhancement integral (PEI, Figure 1D), maximum slope of increase (MSI, Figure 1E), and maximum slope of decrease (MSD, Figure 1F) were automatically generated by the commercial software based on the curve analysis model [17], [18]. According to this model, TTP was defined as the time from the time point when enhancement could be detectable to the time when the maximum signal intensity (SImax) appeared in the spleen.…”

Liver dynamic contrast‐enhanced MRI for staging liver fibrosis in a piglet model

“…The liver DCE‐MRI acquisitions were performed with a modified multiphase fast gradient echo train (FGRET) pulse with the following scanning parameters: repetition time, 14.7 msec; echo time, 3.2 msec; inversion time, 228.2 msec; field of view (FOV), 36–39 × 17–23.4 cm; matrix, 256 × 160; bandwidth, 62.5 kHz; number of signals excitations, 0.5; flip angle, 25°; number of sections, 12; section thickness, 8 mm; slice gap, 1 mm; and acquisition time, 108 seconds. The scanning parameters were referenced from a published article . Additionally, a different FOV used in different piglets was based on their different abdominal sizes; FOV did not differ in the same animal at different timepoints.…”

“…b–f) including time of peak (TOP) demonstrated on this curve, time to peak (TTP), maximum slope of increase (MSI), maximum slope of decrease (MSD), and positive enhancement integral (PEI) were automatically generated by the commercial software. According to the published articles , TOP was defined as the time when the maximum signal intensity (SImax) of the STC appeared (Fig. b), and TTP was defined as the time from the timepoint when enhancement could be detectable to the time when SImax appeared in the liver.…”

Utility of Contrast-Enhanced Transabdominal Ultrasonography to Diagnose Early Chronic Pancreatitis

“…Previous studies have also demonstrated that CP with advanced fibrosis is associated with reduced blood vessel density and decreased pancreatic blood flow [ 8 – 10 ]. Several studies have correlated the grade of CP (degree of fibrosis) with decreased pancreatic blood flow on dynamic contrast-enhanced magnetic resonance imaging (MRI) [ 11 , 12 ]. However, the utility of CEUS in identifying degree of fibrosis in CP, especially early CP, remains unclear.…”