RESUMO
Objective To evaluate the value of diffusion-weighted imaging(DWI)on differential diagnosis of intracranial cystic lesions.Methods Seventy-six patients with surgically and pathologically confirmed intracranial cystic lesions undergone conventional MRI,DWI and contrast enhanced MRI examination.The signal characteristics of intracrania]cystic lesions on DWI were analysed retrospectively, the apparent diffusion coefficient(ADC)values of cystic areas were measured quantitatively.Results Nineteen brain abscesses showed hyperintense signal on DWI.Among 34 brain tumors,3 brain gliomas were hyperintense signal,1 brain glioma was isointense signal and 1 metastasis was hyperintense signal;the other 29 brain tumors showed hypointense signal on DWI.The ADC values of all lesions were:(0.62?0.15)? 10~(-3)mm~2/s in brain abscesses,(2.39?0.78)?10~(-3)mm~2/s in brain gliomas,(2.68?0.40)? 10~(-3)mm~2/s in brain hemangioblastomas,(2.79?0.79)?10~(-3)mm~2/s in brain metastases,respectively. There were significant differences between the ADC values of brain abscess and the cystic or necrotic portions of brain glioma,hemangioblastoma,metastasis(P0.05). Seven intracranial arachnoid cysts showed hypointense signal and 16 epidermoid cysts strikingly hyperintense signal on DWI.The ADC values of arachnoid cysts and epidermoid cysts were(2.96?0.36)?10~(-3)mm~2/s and(0.94?0.13)?10~(-3)mm~2/s respectively.There was significant difference between the ADC values of arachnoid cysts and epidermoid cysts(P