Intra voxel Incoherent Motion Diffusion-weighted Imaging Quantitative Parameters in Evaluating Differentiated Degrees of Pancreatic Cancer / 中国医学影像学杂志

Purpose To explore the application of intra voxel incoherent motion diffusionweighted imaging (IVIM-DWI) quantitative parameters in evaluating the pathological stage of pancreatic cancer by comparing the manifestations of IVIM-DWI in patients with pancreatic cancer in different differentiaed degrees as there lacked effective screening instrument for the early diagnosis of pancreatic cancer.Materials and Methods Sixteen patients with pathologically proved pancreatic cancer (10 with high-moderation differentiation while 6 with low differentiation) were enrolled,and 3.0T MRI was used to conduct pancreatic DWI with multiple b values.IVIM double-exponential model was used to analyze the measurement parameters of DWI with multiple b values,so as to measure the slow apparent diffusion coefficient (ADCslow),fast apparent diffusion coefficient (ADCfast) and filling fraction (f).Results The ADCslow value was evidently lower in patients with high-moderate differentiated pancreatic cancer than those with low differentiated pancreatic cancer [(0.546± 0.041)× 10-3 mm2/s vs.(0.677± 0.120)× 10-3 mm2/s,P＜0.05],and f value was notably higher in patients with high-moderate differentiated pancreatic cancer than those with low differentiated pancreatic cancer [(59.3 ± 8.8)％ vs.(41.7±22.4)％,P＜0.05].The area under the curve of ADCslow was higher than that of f when distinguishing high-moderate differentiated and low differentiated pancreatic cancer (0.850＞0.750).The sensitivity and specificity were 100.00％ and 83.33％ when ADCslow ≤ 0.599×10-3 mm2/s,and were 100.00％ and 66.67％ when f＞44.7％ in distinguishing high-moderate differentiated and low differentiated pancreatic cancer,respectively.Conclusion ADCslow and f,as the quantitative parameters for IVIM-DWI,can distinguish high-moderate differentiated and low differentiated pancreatic cancer,and predict the pathological stage of pancreatic cancer before operation.Moreover,they also have high diagnostic efficacy in distinguishing high-moderate differentiated and low differentiated pancreatic cancer.

The application value of monoexponential,biexponential models multiple b values DWI in pancreatic cancer / 实用放射学杂志

Objective To explore the application value of monoexponential, biexponential models multiple b values diffusion weighted imaging(DWI) in distinguishing pancreatic cancer from non-tumorous pancreas.Methods Subjects comprised 37 pancreatic cancers confirmed by clinical or surgery.Pancreas multiple b values DWI was performed using 3.0T scanner.Standard apparent diffusion coefficient (ADCstandard) was calculated using monoexponential diffusion model.Pure diffusion coefficient (ADCslow), pseudodiffusion coefficient (ADCfast) and perfusion fraction (f) were calculated using intravoxel incoherent motion(IVIM) diffusion model.Parameters of pancreatic cancers and non-tumorous pancreas were compared using independent samples t test.Results Mean ADCslow value of pancreatic cancer was higher than that of non-tumorous pancreas (0.611×10-3 mm2/s vs 0.521×10-3 mm2/s,P=0.037).Mean ADCfast and f values of pancreatic cancer were lower than that of non-tumorous pancreas (5.066×10-3 mm2/s vs 7.188×10-3 mm2/s,P=0.035;55.8% vs 64.0%,P=0.016;respectively).ADCslow of pancreatic cancer was positively correlated to ADCstandard (r=0.824,P=0.000).ADCfast of pancreatic cancer was negatively correlated to f(r=-0.558,P=0.000).Conclusion ADCslow, ADCfast and f derived from IVIM-DWI model can distinguish pancreatic cancer from non-tumorous pancreas.IVIM-DWI may be a promising and non-invasive tool for early diagnosing and differentiating pancreatic carcinoma from non-tumorous pancreas.

Analysis of CT fingings and the causes of missed diagnosis of insulinoma / 实用放射学杂志

Objective To analyze CT findings of insulinoma,and to summarize the causes of missed diagnosis of nontypical insuli-noma.Methods Clinical and CT manifestations of 18 patients with 18 insulinomas were analyzed retrospectively which were proved by surgery and pathology,and the causes of the missed diagnosis of nontypical insulinoma were also summarized.Results 10 patients with 10 insulinoma underwent CT plain scan with isodensity in 9 and slightly lower density in 1 with thread-like capsule.Other 18 patients underwent enhanced CT scan,10 of whom showed obvious enhancement in arterial phase with isodentisy in 6 and slightly higher density in 4 in portal phase,and isodensity in 10 in delayed phase.4 lesions showed mild-to-moderate enhancement in arterial phase with slightly higher density than normal pancreas in 2 and isodentisy in 2 in portal phase,and slightly higher density than nor-mal pancreas in 1 and similar density to pancreas in 3 in delayed phase.In portal phase,the enhanced degree in 8 was similar to the pancreas,and that in 6 was slightly higher or higher than that of pancreas.In delayed phase,13 were similar to the pancreas and other 1 was higher than that.3 of 18 lesions were easily missed,and 4 lesions with missed diagnosis showed isodensity on plain CT and en-hanced CT,and were further detected by other imaging methods.Conclusion Multiphase enhancement CT scanning can be used as the first choice for the insulinoma.