Evaluation parameters between intra-voxel incoherent motion and diffusion-weighted imaging in grading and differentiating histological subtypes of meningioma: A prospective pilot study.

Purpose: To prospectively evaluate the usage of intra-voxel incoherent motion (IVIM) magnetic resonance imaging (MRI) parameters in grading and differentiating histological subtypes of meningiomas and in comparing their ability with the traditional diffusion-weighted imaging (DWI) parameter (apparent diffusion coefficient, ADC).

Methods: In this prospective study, 102 participants underwent IVIM MRI and DWI. Traditional DWI and IVIM MRI were performed by using 2 b values (0, 1000s/mm) and 12 b values (0-3500s/mm), respectively. Finally, the values of ADC and IVIM parameters were collected from 72 Grade I and 11 Grade II meningiomas.

Results: The mean ADC values of Grade II and Grade I meningiomas were 0.909±0.268×10mm/s and 0.905±0.194×10mm/s, respectively, p=0.967. The D values were lower in Grade II meningiomas than in Grade I meningiomas (0.459±0.072×10mm/s vs. 0.524±0.030×10mm/s, respectively, p=0.005). In ROC curves, the cut-off D value that separated Grade II meningiomas from Grade I meningiomas was 0.479×10mm/s with a sensitivity of 90.9% and a specificity of 76.7%. The secretory and angiomatous meningiomas had higher IVIM parameters than the other subtypes (all p<0.05). D* was significantly lower in fibrous meningiomas than in other meningiomas (2.783±1.179×10mm/s vs. 5.125±1.918×10mm/s, p<0.001). D, rD and rf values correlated negatively with Ki-67 index while D* and rD* value had positive relation with Ki-67 values.

Conclusion: IVIM MRI is a promising technique for distinguishing different grades of meningiomas. Different subtypes of meningiomas have different IVIM features, which may help to treatment decision and prognosis evaluation.