Evaluation of the value of X、CT and MRI in diagnosis of spinal echinococcosis

Objective To analyze the manifestation and images of spinal echinococcosis retrospectively,and critically examine and elucidate the diagnosis and diagnostic pitfalls of the disease. Methods From October 1957 to June 2006,twenty-five consecutive cases in 5721 cases of echinococcosis collected,which comprised 14 males and 11 females,the average age were 28.3 years(15~56 years). The average duration of infestation with spinal hydatid disease was 3.2 years(0.5~12 years). Nineteen cases underwent MRI scanning. The lesions were located in the cervical vertebrae in 3,the thoracic vertebrae in 11,the lumbar vertebrae in 5 and the sacrum in 6 cases. Results Twenty-three cases in the total(92%)were come from farms or contaminated with dogs and sheep intimately. All the cases were under the examination of X-ray films at first,then CT examination were performed in 13 of the 25 cases and 5 of these were diagnosed as having spinal hydatid disease(38.46%). MRI examination were performed in 19 of the 25 cases and 17 of these were diagnosed as spinal hydatid disease(89.47%). The typical MRI appearance was that of a multilocular cyst and the signal of the parent cyst was similar to that of muscle and higher than that of secondary cyst in the T1 Weighted Image(WI). The Casoni test were performed in 15 cases and positive in 12 patients(80%). In addition,4 cases were positive in all of the so-called 8-tests of immunodiagnostic methods. Conclusion Whereas X-ray or CT images of spinal echinococcosis are similar to tuberculosis,metastases,giant cell tumor,or cyst of bone,MRI shows distinctive diagnostic features of spinal hydatid disease. Serological examinations are important to confirm the correct diagnosis.