4983
Optimization of high b values for intravoxel incoherent motion imaging of rectal cancer : a pilot study1Department of Radiology, National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People's Republic of China
Synopsis
To optimize the high b values (>200s/mm2) for intravoxel incoherent motion imaging of rectal cancer and to observe the effect of high b values variation on IVIM parameters. Three groups (A group with all 16 b values: 0,10,20,30,40,60,80,100,150,200,400,800,1000,1200,1500,2000, B group with 14 b values: 0,10,20,30,40,60,80,100,150,200,400,800,1000,1200 and C group with 12 b values: 0,10,20,30,40,60,80,100,150,200,400,800) were selected respectively for measurement by a radiologist. The average values of each measurement were used for statistical analysis. One-way analysis of variance (ANOVA) and post-hoc test were performed on the mean values of IVIM parameters in groups A, B, and C, with a significance level of P＜0.05. The p values of ANVOA results in ADC、D、D* values were less than 0.05, the differences were statistically significant. The p values of Bonferroni post-hoc test in D、D*、f values were not statistically significant differences in group A and B. With the number of high b values decrease, the values of ADC、D、D* values and standard error were increased, while of f values was not changed significantly. In our study, the reproducibility of the IVIM parameters caused by high b value variation was not significant. The value of selected b > 1500 need to be further studied.
Objective
To optimize the high b values (>200s/mm2) for intravoxel incoherent motion imaging of rectal cancer and to observe the effect of high b values variation on IVIM parameters.Methods
Twenty two patients with rectal adenocarcinoma were included the prospective study. Three groups (A group with all 16 b values: 0,10,20,30,40,60,80,100,150,200,400,800,1000,1200,1500,2000, B group with 14 b values: 0,10,20,30,40,60,80,100,150,200,400,800,1000,1200 and C group with 12 b values: 0,10,20,30,40,60,80,100,150,200,400,800) were selected respectively for measurement by a radiologist (with 10 years of experience in gastrointestinal cancer imaging). The largest slice of the solid components of the tumor was selected for measurement in the IVIM metrics map (b=800). Monoexponential ADC and biexponential IVIM metrics maps and IVIM parameters were generated automatically by the software. The same measurement were repeated after one week apart. The average values of each measurement were used for statistical analysis. The consistency and reproducibility of the two measurements were analyzed by Bland-Altman plots. One-way analysis of variance (ANOVA) and post-hoc test were performed on the mean values of IVIM parameters in groups A, B, and C, with a significance level of P＜0.05.Results
The D* values variations of 95% limits of agreement (LoA) between groups A, B and A, C were relatively large. The 95% LoA of ADC、D values between groups were not obvious. The p values of ANVOA results in ADC、D、D* values were less than 0.05, the differences were statistically significant. The p value of ANVOA results in f values was greater than 0.05, the difference was not statistically significant. The p values of Bonferroni post-hoc test in D、D*、f values were not statistically significant differences in group A and B. With the number of high b values decrease, the values of ADC、D、D* values and standard error were increased, while of f values was not changed significantly.Conclusions
In our study, the reproducibility of the IVIM parameters caused by high b value variation was not significant. The value of selected b > 1500 need to be further studied.Acknowledgements
No acknowledgement found.References
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