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

ABSTRACT

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.