Research On The Diagnostic Value Of Multi-exponential Models Of Diffusion-weighted MR Imaging In Acute Pancreatitis

Objective: To investigate the diagnostic value and the clinical severity classification of acute pancreatitis with mono-exponential model,bi-exponential model based on intravoxel incoherent motion,and stretched-exponential model diffusion-weighted MR imaging based on aquaporin.Methods: According to inclusion criteria,a total of 53 patients with confirmed acute pancreatitis and 20 healthy volunteers were prospectively recruited from August 2016 to February 2017.All subjects had conventional abdominal MRI and 14 b values(0,25,50,75,100,150,200,400,600,800,1000,1200 1500,2000s/mm2)DWI scan.Acute pancreatitis were divided into mild,moderately severe and severe types according to the Balthazar classification standard.The parameter standard ADC,slow ADC mono,fast ADC mono,Ff ADC mono,slow ADC Bi,fast ADC Bi,Ff ADC Bi,DDC and ? derived from mono-exponential,bi-exponential,stretched-exponential models were respectively measured and compared to assess the diagnostic value and clinical severity gradation of acute pancreatitis.Result: Independent samples T Test showed significant differences in mono-exponential model parameter standard ADC,bi-exponential model parameter Ff ADC mono,stretched-exponential model DDC and ? between AP group and NP group(p=0.003,0.009,0.000,0.000),but the parameter slow ADC mono,fast ADC mono,slow ADC Bi,fast ADC Bi,Ff ADC Bi had no statistic differences(p = 0.658,0.582,0.494,0.483,0.975).Areas under the ROC curves of parameter standard ADC,Ff ADC mono,DDC and? were 0.758,0.697,0.744 and 0.806 respectively.The sensitivities were81.1%,64.2%,81.1% and 79.2%,and the specificity were 65.0%,75.0%,60.0%,75.0%.Pairwise comparison showed no statistical significance in the diagnostic efficacy between the parameter standard ADC and Ff ADC mono,standard ADC and DDC,standard ADC and ?,Ff ADC and DDC,Ff ADC mono and ?,DDC and ?(p = 0.235,0.728,0.590,0.212,0.237,0.488).Analysis of Variance showed statistical differences in parameter standard ADC,Ff ADC mono,DDC,and ? among MAP,MSAP and SAP(p= 0.002,0.007,0.000,0.017).LSD multiple comparison showed statistical differences in parameter standard ADC,Ff ADC mono,DDC,and ? between MAP and SAP(p=0.001,0.002,0.002,0.013).There were statistical differences in parameter Ff ADC mono and ? between MAP and MSAP(p=0.028,0.026),while standard ADC and DDC showed no differences(p=0.074,0.059).There were statistical differences in parameter standard ADC,Ff ADC mono and DDC between MSAP and SAP(p=0.012,<0.001,0.046),while ? showed no difference(p=0.253).Conclusion: Mono-exponential model parameter standard ADC,bi-exponential model parameter Ff ADC mono,stretched-exponential model DDC and ? can be used for the diagnosis of acute pancreatitis and are conducive to its severity classification.