on on PWI. Conclusions MRI can demonstrate hydatid cysts in vertebra, spinal canal, paravertebral and neighboring soft tissue. MRI is a valuable tool in the diagnosis and treatment planning of hydatid disease of the spine.

Objective To study the characteristic findings of brain echinococcosis on MRI. Methods The MRI findings of 18 patients with pathologically confirmed brain echinococcosis were retrospectively reviewed.Results Among the patients.there were 9 cases of cystic echinococcosis and 9 cases of alveolar echinococcosis.In cystic echinococeosis,MRI revealed homogeneously hypointensity on T1WI and hyperintensity on T2WI,while it showed low signal intensity inside the cysts on FLAJR and DWI. In 6 cases of cystic echinococcosis, no edema was detected surrounding the lesions,while edema resulting from cyst rupture was found in 3 cases.The cystic walls were visible in 6 csses, obscure in 3 cases.The ruptured hydatid cysts in 3 cases showed slight ring enhancement.Alveolar echinococcosis appeared as multiple lesions with isointensity on T1WI and hypointensity on T2WI,surrounded by vasogenic edema.The "charcoal-like"hypointensity and innumerous hyperintense bubbles of 1-10 mm in diameter inside the lesions on T2-weighted MR images were characteristic for lesions of alveolar echinococcosis.The lesions revealed hypointensity on DWI and showed irregular ring enhancement after injection of Gd-DTPA. Perfusion-weighted MR imaging revealed low relative cerebral blood volume.Conclusion MRI can demonstrate lesions of brain echinococcosis accurately due to its advantages of multiorientation and multiparameter.It is clinically valuable.

Objective To investigate the clinical application of magnetic resonance hydrography(MRH) in diagnosing cystic echinococcosis(CE).Methods 47 cases with CE were proved by surgery and pathology.All cases were examed by MRI and MRH.Results Among the 151 lesions in 47 cases,the sensitivity and specificity in diagnosis of CE were 61.59% and 93.33% for MR imaging,92.05% and 86.67% for MRH,respectively.Conclusion The detecting rate of MRH was significant high than that of MRI,MRH combined with MRI has more advantages in diagnosis of CE.