Comparing the value of DKI and DTI in detecting isocitrate dehydrogenase genotype of astrocytomas

To compare the value of diffusion kurtosis imaging (DKI) and diffusion tensor imaging (DTI) in evaluating astrocytomas with an isocitrate dehydrogenase (IDH) genotype.

Fifty-eight astrocytomas were divided into IDH-wild-type (IDH-W) and IDH-mutant (IDH-M) groups, in all astrocytomas, low-grade astrocytomas (LGA) and high-grade astrocytomas (HGA), respectively. The DKI (mean kurtosis [MK], radial kurtosis [Kr], axial kurtosis [Ka]), and DTI (fractional anisotropy [FA], mean diffusivity [MD]) values were measured. The differences of parameter values between the IDH-W and IDH-M groups were compared by t-test. Receiver operating characteristic (ROC) curves were used to identify the best parameter and z-score tests were used to compare the performance between DKI and DTI.

In all astrocytomas, MK, Ka, and Kr values were significantly higher (p<0.001, p=0.002, and p<0.001), and the MD value (p=0.005) was lower in the IDH-W group than those in the IDH-M group. The areas under the ROC curve (AUC) of MK (0.811) and Kr (0.800) were significantly higher than that of MD (0.704). In LGA, MK, Ka, and Kr values were also significantly higher in the IDH-W group than those in the IDH-M group (p=0.002, p=0.008, p=0.006), whereas MD and FA values showed no differences. In HGA, MK and Kr values were significantly higher (p=0.008, p=0.003), and the MD value (p=0.031) was significantly lower in the IDH-W group than that in the IDH-M group, the AUC of MK (0.750) and Kr (0.788) were also higher than MD (0.637; p=0.032, p=0.025).

DKI may be a new imaging biomarker for evaluating the IDH genotype of astrocytomas, which is more accurate and stable than DTI.