Correlation of Intravoxel Incoherent Motion-derived Parameters with Computer Tomography Perfusion Parameters in Insulinoma

Abstract

Objective To prospectively evaluate the correlation between intravoxel incoherent motion (IVIM)-derived parameters and CT perfusion parameters as well as the pathological grade in insulinoma. Methods A total of 55 patients with suspected insulinoma undergoing IVIM and CT perfusion scans were prospectively enrolled. The images were post-processed to obtain IVIM parameters including apparent diffusion coefficient (ADC),diffusion (D),perfusion correlated diffusion (D*),and f,and CT perfusion parameters including blood flow (BF),blood volume (BV),and permeability (PM). The pathological specimens were stained to obtain pathological parameters including the grading,ki-67 index,and the mitotic count. The IVIM derived parameters of normal pancreas including head,body,and tail as well as that of the pancreatic insulinoma were compared. The correlation between IVIM parameters and CT perfusion parameters as well as the pathological parameters was analyzed. Results ADC and D values of pancreatic tail were significantly lower than those of the pancreatic head and neck (all P<0.001). There were significant differences in all IVIM parameters between insulinoma and normal pancreas (all P<0.001). The ADC and f value of the normal pancreas was positively correlated with BF (r=0.437,P=0.003;r=0.357,P=0.010). There is no correlation between the remaining IVIM parameters and the CT perfusion parameters as well as between IVIM parameters and pathological parameters (all P>0.05). Conclusions IVIM parameters differ at different anatomical parts of normal pancreas. IVIM parameters can distinguish normal pancreatic parenchyma from insulinoma. The ADC value is weakly correlated with BF.