Objective To explore the value of the diagnosis and differential diagnosis of the sacral tumors with MRI. Methods Twenty nine patients with histologically proven sacral tumors were viewed, including sacral chordoma( n =5), giant cell tumor( n =1), neurilemmona( n =3), ganglioneuroma( n =2), malignant lymphoma( n =4), osteosarcoma( n =1), malignant neurilemmoma ( n =1), and secondary tumors ( n =12).All patients were examined with MR,CT and plain radiograph. MR findings were analyzed. Results (1) sacral tumors involved sacral bone with a regularity. Four patients with sacral chordoma involved usually above S3 level, not including S1 bone. One patient with giant cell tumor involved S2 S3. Six patients with neuromas involved S1 S3, including S1 bone. (2) signal intensity: moderate and/or low signal on T 1 weighted images, mottled signal on T 2WI. (3) sacral pores were destructed, disappeared, or enlarged. Sacral pores enlarged in six patients with neuromas, destructed in others. (4) sacral canal were destructed, disappeared, or enlarged. (5) tumors were classified into central ( n =16), centrifugal ( n =9), and mixed ( n =4) types. (6) sacral tumors were segmental on sagittal MR images. Conclusion MRI is superior to CT and plain X ray in assessing classification, segment and sacral pores and the like, so MRI is very important to the diagnosis and the differential diagnosis of the sacral tumors.

Objective:To assess the value of spiral CT in diagnosis and treatment of chronic otitis media.Methods:The spiral CT findings of 74 cases including 93 ears proved by operation and pathology were studied.Results:The lesions such as the disruption of the ossicular chain showed in spiral CT or three-dimensional image were in accord with those seen in the operation,the accuracy was 95.7%,the disruption of the ossicular chain and bony erosion in the tympanic cavity and antrum were severe in the typeⅢ chronic otitis media.Conclusion:Spiral CT is helpful to diagnose and definite the chronic otitis media,three-dimensional image can provide valuable information for surgery.