Objective To analyze the CT and MRI manifestations of congenital cholesteatoma of petrous bone ,and evaluate the efficacy of it in the clinical practice.Methods Imaging findings in 27 pathological-proved cases were review. Imaging materials included CT scan in 26,MRI scan in 11.Results Petrous bone wall erosion and expanding tumor was observed with CT(n=23),tumor was not oberved with CT(n=3).Congenital choleseatoma signal intensity was intermediate or low on T 1W images and high on T 2W images in 11 cases.Conclusion The role of MRI and CT is affirming in the evaluation of congenital choleseatoma of the petrous bone. MRI is superior to CT for the evaluations of involvement of the membranous labyrinth and intracranial structures.

Objective To investigate the value of volume reconstruction ( VR ) in showing the ear lesions and to compare with otherpost-processed methods.Methods 15 patients with hearing loss underwent MSCT ultra-high resolution scan with collimation 0.5 mm,pitch 0.5~0.875 and increment 0.1mm.An additional enhanced CT was performed in 10 of 15 cases. The various reconstructions including VR , MPR, SSD, VE, Ray Sum and MIP/MinIP were performed for the comparison of their ability in showing the ear lesions and the invasion of the auditory ossicals and the inner ear of the adjacent tumors. Results VR was the most optimal way, in showing the ear lesions,successionally in descending order was VR, MPR, SSD, MIP/MinIP. Ray Sum and VE were only suitable for showing the lesions of the inner ear and auditory ossicles respectively.Conclusion The data acquired from the scan of MSCT using 0.5 mm collimation can be used in various reconstruction methods including VR, MPR, SSD and MIP/MinIP to display the lesions of the ear and the invasion of the ear fine structures from the plane and three-dimensional view. VR is the best way, which can display the relationship between tumor and facial/auditory nerve, labyrinth .

Objective To describe CT and MRI findings of the global choroidal hemangioma, and to investigate their value in the diagnosis and differentiation. Methods Nine choroidal hemangioma patients proven by surgical pathology( n =3)or clinic information ( n =6) were analyzed. CT scan was performed in 6 cases and MRI in 4 cases. All cases were examined by ultrasound and 3 with fundus fluorescein angiography (FFA). Results Two cases showed slight or crescent like thickening and iso density with respect to the global wall on CT scan. 5 cases on enhanced CT showed a flat or shuttle shaped homogeneous mass with marked enhancement. MRI ( n =3) revealed high signal intensity on T 1WI and low signal intensity on T 2WI with respect to the vitreous. 1 small tumor was found clearly by postcontrast fat suppressed T 1WI. Ultrasound showed homogeneous mass ( n =1) and inhomogeneous mass ( n =8), with retinal detachment in all cases. Conclusion CT + MRI + ultrasound can get most of the diagnostic imaging data for choroidal hemangioma. MRI was superior to CT and ultrasound in the diagnosis of choroidal hemangioma and differential diagnosis from other malignant tumors.