The Value Of MR Multi B Value Diffusion Weighted Imaging And Dynamic Susceptibility Contrast-enhanced Perfusion Imaging In Cerebral Astrocytoma Grading

Objective:To explore the value of MR multi b value diffusion weighted imaging and dynamic susceptibility contrast-enhanced(DSC) perfusion imaging in cerebral astrocytoma grading. Methods:22 patients with high grade astrocytoma and 28 patients with low grade astrocytoma confirmed by pathology have been collected from November 2013 to October 2015. All patients underwent conventional MRI scanning, IVIM and DSC scanning before operation. Standard diffusion coefficient(ADCstandard), slow diffusion coefficient(D), fast diffusion coefficient(D*), fractional perfusion-related volume(f)values and blood volume(CBV), blood flow(CBF)values of tumor solid part were measured quantitatively by using parameter maps progressing from the workstations. Compare the values between the two groups by two samples t-test, by using receiver operating characteristic(ROC) curve to assess the size of area under the curve(AUC) of each parameter value. Compare the correct rate of cerebral astrocytoma grading for IVIM and DSC scanning and IVIM combining with DSC scanning. Resluts:(1) The ADCstandard,D values of tumor solid part in high-grade astrocytomas were significantly lower than that of low-grade astrocytomas(p=0.000, p<0.05), The D*,f values of tumor solid part were no significant differences(p=0.130,p=0.379), The CBV,CBF values of tumor solid part in high-grade astrocytomas were significantly higher than that of low-grade astrocytomas(p=0.000, p<0.05).(2) ROC curve analysis showed that when the ADCstandard values of tumor solid part was 1.752, the sensitivity and specificity for the grading of cerebral astrocytomas was 83.3% and 80% respectively, the AUC was 0.823,and when the D values of tumor solid part was 1.376, the sensitivity and specificity for the grading of cerebral astrocytomas was 86.7% and 70% respectively, the AUC was 0.854,and when the CBV values of tumor solid part was 5.426, the sensitivity and specificity for the grading of cerebral astrocytomas was 80% and 86.7% respectively, the AUC was 0.858,and when the CBF values of tumor solid part was 5.733, the sensitivity and specificity for the grading of cerebral astrocytomas was 76.7% and 86.7% respectively, the AUC was 0.848.(3) The accuracy of IVIM combining with DSC scanning of the grading of cerebral astrocytomas is better than the IVIM and DSC scanning alone.(when the D combining with CBV values, the sensitivity and specificity for the grading of cerebral astrocytomas was 90% and 96.7% respectively, the AUC was 0.952 and when the D combining with CBF values, the sensitivity and specificity for the grading of cerebral astrocytomas was 93.3% and 86.7% respectively, the AUC was 0.953.) Conclusions:(1) The ADCstandard and D values of tumor solid part were helpful in grading of cerebral astrocytomas.(2) The D* and f values of tumor solid part in grading of cerebral astrocytomas should be further studied.(3)The combination of IVIM scanning and DSC scanning can improve the accuracy of grading of cerebral astrocytomas.