Apparent Diffusion Coefficient Histogram Analysis:Diffirentiation Of Genetic Subtypes Of Diffuse Lower-Grade Gliomas

ObjectiveTo explore the utility of ADC histogram analysis in differentiation of genetic subtypes（e.g.IDH mutation status and 1p/19q co-deletion）in diffuse lower-grade gliomas.MethodsA total of 55 patients with WHO gradeⅡandⅢdiffuse gliomas,who underwent preoperative routine brain MRI sequences and DWI,were retrospectively evaluated,including 14 patients with isocitrate dehydrogenase（IDH）wild-type gliomas（IDH^wtt group）,19 patients with IDH-mutant 1p19q intact gliomas(IDH^mut1p19qⁱntnt group),and 22 patients with IDH-mutant 1p19q co-deleted gliomas(IDH^mut1p19q^del).The whole-lesion ADC values derived from histogram anlysis（including ADCmean,ADCmin,ADC5%,ADC10%,ADC25%,ADC50%,ADC75%,ADC90%,ADC95%,ADCmax,mode,range,skewness,kurtosis,StDev,inhomogenity,entrophy）were measured for each patient.All parameters between the different genetic subtypes were compared by using the Student’s t test or Mann-Whitney U test.ROC analysis was used to assess the diagnostic performance of ADC histogram in distinguishing the different genetic subtypes.ResultsCompared with the IDH^mutut gliomas,the ADC75%,ADC90%,ADC95%,ADCmax,range,StDev and inhomogenity were significantly higher in the IDH^wtt gliomas,in contrast,the ADCmin and kurtosis were significantly lower in the IDH^wtt gliomas（all P<0.05）.Betweent the IDH^mut1p19qⁱntnt gliomas and the IDH^mut1p19q^delel gliomas,the ADCmean,ADC5%,ADC10%,ADC25%,ADC50%and mode were significantly lower in the IDH^mut1p19q^delel glomas,and the skewness of the IDH^mut1p19q^delel gliomas is higher than that of the other group（all P<0.05）.Inhomogenity achieved the highest AUC（0.811）in differentiating IDH^mutut gliomas and IDH^wtt gliomas,when a cutoff value was 0.229,the sensitivity and specificity were 85.7%and 73.2%.ADCmode achieved the highest AUC（0.744）in differentiating IDH^mut1p19qⁱntnt gliomas and IDH^mut1p19q^delel gliomas,when a cutoff value was 1448.75×10^-66 mm²/s,the sensitivity and specificity were 57.9%and 90.9%.ConclusionADC histograms analysis may be helpful to differentiate genetic subtypes in lower-grade gliomas.