Objective      To investigate the application value of multi-b intravoxel incoherent motion (IVIM) diffusion-weighted MR imaging for preoperative evaluation of tumor grade in gliomas. Methods      Forty patients with pathologically confirmed gliomas (18 cases of low grade and 22 cases of high grade) admitted in our hospital from July 2015 to July 2016 were enrolled in this study. They received conventional MR plain scanning

enhanced scanning and multi-b of IVIM sequences scanning. Four parameters including apparent diffusion coefficient (ADC) standard

slow diffusion coefficient (D)

fast diffusion coefficient (D*) and fraction of fast perfusion fraction (f) were measured in the 3 areas

i.e.

tumor parenchyma region

periphery surrounding the tumor and the semioval center of contralateral side. The data was compared between low and high grade gliomas and correlation of the parameters to the pathological grade was analyzed. Results      In all patients

the values of ADCstandard

D and D* in tumor parenchyma and peripheral regions were significantly higher than in the semioval center of contralateral side. Also

the D and D* values were significantly higher in tumor parenchyma region compared with periphery region (P0.05). The value of ADCstandard

D

D*

and f in high and low grade gliomas were (1.09±0.22，1.48±0.32)×10-3 mm2/s

(0.78±0.17，1.21±0.23)×10-3 mm2/s

(32.65±9.91，17.12±7.74)×10-3 mm2/s

(0.47±0.08，0.29±0.07)

respectively. Compared with low grade group

high grade glioma patients had significant lower value of ADCstandard and D (t=4.391 and t=6.236) but higher D* and f (t=-5.290 and t=-7.177) in tumor parenchyma area (P0.05). The Pearson correlation analysis illustrated that the ADCstandard and D values were negatively related to glioma grade whereas D* and f were positively associated. In addition

the receiver operating characteristic (ROC) analysis showed that the area under the curve and the diagnostic threshold for ADCstandard

D

D* and f were (0.851，1.23×10-3 mm2/s)

(0.939，0.92×10-3 mm2/s)

(0.899，20.6×10-3 mm2/s)

and (0.957，0.36)

respectively. Conclusion     Our data demonstrated significant difference of ADCstandard

D

D* and f between high and low grade gliomas measured by multi-b IVIM MR imaging. This non-invasive IVIM imaging can detect diffusion and perfusion changes in tissue

which may be useful for preoperative evaluation of tumor grade in gliomas.