Grading of IDH-mutant astrocytoma using diffusion, susceptibility and perfusion-weighted imaging

Background The accurate grading of IDH-mutant astrocytoma is essential to make therapeutic strategies and assess the prognosis of patients. The purpose of this study was to investigate the usefulness of DWI, SWI and DSC-PWI in grading IDH-mutant astrocytoma. Methods One hundred and seven patients with IDH-mutant astrocytoma who underwent DWI, SWI and DSC-PWI were retrospectively reviewed. Minimum apparent diffusion coefficient (ADC(min)), intratumoral susceptibility signal intensity(ITSS) and maximum relative cerebral blood volume (rCBV(max)) values were assessed. ADC(min), ITSS and rCBV(max) values were compared between grade 2 vs. grade 3, grade 3 vs. grade 4 and grade 2 + 3 vs. grade 4 tumors. Logistic regression, tenfold cross-validation,and receiver operating characteristic (ROC) curve analyses were used to assess their diagnostic performances. Results Grade 4 IDH-mutant astrocytomas showed significantly lower ADC(min) and higher rCBV(max) as compared to grade 3 tumors (adjusted P < 0.001). IDH-mutant grade 3 astrocytomas showed significantly lower ITSS levels as compared with grade 4 tumors (adjusted P < 0.001). ITSS levels between IDH-mutant grade 2 and grade 3 astrocytomas were significantly different (adjusted P = 0.002). Combined the ADC(min), ITSS and rCBV(max) resulted in the highest AUC for differentiation grade 2 and grade 3 tumors from grade 4 tumors. Conclusion ADC(min,) rCBV(max) and ITSS can be used for grading the IDH-mutant astrocytomas. The combination of ADC(min,) ITSS and rCBV(max) could improve the diagnostic performance in grading of IDH-mutant astrocytoma.