[The study of MRI examination of acoustic neuromas].

OBJECTIVE

To discuss the examination parameters of acoustic neuromas.

METHOD: The MRI features of 20 lesions 20 patients with acoustic neuroma had been analyzed retrospectively. The examinations were performed by a 1.5 Tesla superconducting magnet system transaxial T1. T2-weighted imagines and coronal or sagittal T1. T2-weighted imagines were obtained in each cases. 20 patients were examined with Gd-DTPA.

RESULT: 20 cases of acoustic neuroma were divided into three groups according to the tumor size: 1.1 approximately 2 cm (4 lesion) ;2. 2 approximately 4 cm (14 lesion); 3. over 4 cm (2 lesion). T1 weighted imagines shovos the equal or low signal;T2 weighted imagines shows the high signal. Low and high mixture signal will be shown when being hemorrhage or necrosis.

CONCLUSION

Combining thin slice and Gd-DTPA in MRI examination was the best method to find acoustic neuroma. MRI not only can find small intracanalicular tumors, but also has advantages in demonstrating the formation of cyst and hemorrhage, the compression of adjacent anatomical structures and the tumor vessels.