Abstract: This experiment was conducted to study the CT and MRI features of cerebral coenurosis in sheep. Three Xinjiang fine-wool sheep with typical symptoms of cerebral coenurosis were selected, then neurological examination, blood routine, and serum biochemical examination were performed. CT and MRI examinations were performed on two sheep's heads, and the pathological autopsy was performed on all the sheep after the CT and MRI scan to observe the changes. Results were as follows:1) Neurological examination results showed that all animals had nystagmus, bilateral palpebral reflexes, and corneal reflexes of the animals were weakened, and the animals' righting reactions and bilateral wheelbarrowing reactions were abnormal, and no obvious abnormalities in blood routine and serum biochemical examination were found. 2) In the CT images of the sheep, varying amounts of intracranial cystic hypoattenuating structures with a clear margin can be observed, in which CT values were similar to cerebrospinal fluid (CSF). Mass effect correlated with the hypoattenuating structures can be observed as well, and a large number of punctate isoattenuating or hyperattenuating structures invaginated in clusters on the cyst wall can be seen, which were found to be protoscolices. No obvious abnormal attenuating images in the rest of the brain tissue were found; In the MRI images of the sheep, varying amounts of intracranial cystic lesions can be observed, the cystic lesions were characterized by a high signal on T2WI and low signal on T1WI, being accord with CSF signal. Punctate protoscolices embedded in the cyst wall were iso-signal on T1WI and low signal on T2WI, no perilesional abnormal signal was found. 3) Pathological autopsy revealed parasitic cysts filled with clear cystic fluid, which contained varying numbers of protoscolices, the location of the parasitic cysts was consistent with the imaging findings. These results indicated that sheep cerebral coenurosis has characteristic CT and MRI features. Combing two imaging diagnostic methods can accurately locate the parasitic cysts and show the involvement of the surrounding tissues, which is helpful for veterinarians to make surgery treatment plans.

Key words: sheep, cerebral coenurosis, CT, MRI