Purpose To investigate the differential diagnosis of diffusion-weighted imaging(DWI),perfusion-weighted imaging(PWI)and DWI combined with PWI in supratentorial pilocytic astrocytoma(PA)and WHO grade 2 pleomorphic xanthoastrocytoma(PXA).Materials and Methods The conventional MRI,DWI and PWI data of 23 cases of supratentorial PA and 11 cases of PXA(WHO grade 2)in the First Affiliated Hospital of Fujian Medical University from January 2010 to February 2022 were retrospectively analyzed.Supratentorial PA was further divided into lobar PA and non-lobar PA based on the lesion location.The basic data(gender,age,cystic degeneration,homogeneous enhancement,lesion size and meningeal involvement),minimum apparent diffusion coefficient,relative apparent diffusion coefficient and relative maximum cerebral blood volume were compared and analyzed between the two groups.Results The probability of leptomeningeal involvement in PXA(WHO grade 2)(36.3%)was higher than that in supratentorial PA(4.3%,P=0.029).Compared with supratentorial PA and lobar PA,PXA(WHO grade 2)had lower minimum apparent diffusion coefficient,relative apparent diffusion coefficient and higher relative maximum cerebral blood volume(t=-4.398-5.828,all P<0.05).The threshold value of minimum apparent diffusion coefficient to discriminate between supratentorial PA and PXA(WHO grade 2)was 1.09×10-3 mm2/s,and its sensitivity,specificity and area under the curve were 90.91%,83.33%and 0.947,respectively.When the differential diagnosis threshold of relative maximum cerebral blood volume was 1.79,its sensitivity,specificity and area under the curve were 90.00%,100.00%and 0.950,respectively.The area under the curve of DWI combined with PWI was 0.993,which did not significantly improve the diagnostic performance compared with DWI and PWI respectively(Z=1.371,0.928,both P>0.05).In subgroup analysis,the area under the curve of DWI combined with PWI in lobar PA and PXA(WHO grade 2)was 0.988,which did not improve the diagnostic performance compared with DWI and PWI respectively(Z=1.322,0.882,both P>0.05).Conclusion DWI and PWI are helpful in the differential diagnosis of PXA(WHO grade 2)from supratentorial PA and lobar PA,but combining DWI and PWI does not significantly improve the efficacy of differential diagnosis.

Purpose To investigate the differential diagnosis of diffusion-weighted imaging(DWI),perfusion-weighted imaging(PWI)and DWI combined with PWI in supratentorial pilocytic astrocytoma(PA)and WHO grade 2 pleomorphic xanthoastrocytoma(PXA).Materials and Methods The conventional MRI,DWI and PWI data of 23 cases of supratentorial PA and 11 cases of PXA(WHO grade 2)in the First Affiliated Hospital of Fujian Medical University from January 2010 to February 2022 were retrospectively analyzed.Supratentorial PA was further divided into lobar PA and non-lobar PA based on the lesion location.The basic data(gender,age,cystic degeneration,homogeneous enhancement,lesion size and meningeal involvement),minimum apparent diffusion coefficient,relative apparent diffusion coefficient and relative maximum cerebral blood volume were compared and analyzed between the two groups.Results The probability of leptomeningeal involvement in PXA(WHO grade 2)(36.3%)was higher than that in supratentorial PA(4.3%,P=0.029).Compared with supratentorial PA and lobar PA,PXA(WHO grade 2)had lower minimum apparent diffusion coefficient,relative apparent diffusion coefficient and higher relative maximum cerebral blood volume(t=-4.398-5.828,all P<0.05).The threshold value of minimum apparent diffusion coefficient to discriminate between supratentorial PA and PXA(WHO grade 2)was 1.09×10-3 mm2/s,and its sensitivity,specificity and area under the curve were 90.91%,83.33%and 0.947,respectively.When the differential diagnosis threshold of relative maximum cerebral blood volume was 1.79,its sensitivity,specificity and area under the curve were 90.00%,100.00%and 0.950,respectively.The area under the curve of DWI combined with PWI was 0.993,which did not significantly improve the diagnostic performance compared with DWI and PWI respectively(Z=1.371,0.928,both P>0.05).In subgroup analysis,the area under the curve of DWI combined with PWI in lobar PA and PXA(WHO grade 2)was 0.988,which did not improve the diagnostic performance compared with DWI and PWI respectively(Z=1.322,0.882,both P>0.05).Conclusion DWI and PWI are helpful in the differential diagnosis of PXA(WHO grade 2)from supratentorial PA and lobar PA,but combining DWI and PWI does not significantly improve the efficacy of differential diagnosis.