[Imaging diagnosis of masses in temporal bone associated with pulsatile tinnitus]

To improve the imaging diagnosis accuracy on masses of temporal bone associated with pulsatile tinnitus.

The CT and MRI features of masses in temporal bone associated with pulsatile tinnitus in 32 cases, confirmed by pathology, were retrospectively analyzed.

They were grouped into two according to the jugular bulb involved or not. In the group involving the jugular bulb, there were 5 cases with glomus jugular, 2 cases of them presented the feature of "salt-pepper". There were 5 cases with middle ear carcinoma, which presented the masses in the tympanic cavity and antrum, extended to the external auditory canal and eroded the eustachian tube and jugular bulb. There were 3 cases with endolymphatic sac tumors, which presented multiple bony spicules on CT images and high signal on T1-weighted images. There was 1 case with metastatic tumor, which extensively eroded temporal and occipital bone, involved the jugular bulb, presented intermediate signal on T1-weighted images and intermediate or high signal on T2-weighted images, moderately enhanced following contrast administration. In the group not involving the jugular bulb, there were 15 cases with tympanic glomus, without ossicles and tympanic erosion, 7 cases of them limited to the promontory, 7 cases of them filled the tympanic cavity and antrum and 5 cases extended deep into the external auditory canals, 1 case extended to the mastoid, 12 cases intensely enhanced with gadolinium. There were 2 cases with cholesterol granulomas of the middle ear, which presented the masses in the tympanic cavity and antrum and high T1-weighted and T2-weighted signal. There was 1 case with facial nerve hemangioma, which presented the enlargement and mass of the geniculate fossa involving the tympanic segment of facial nerve with the erosion and displacement of ossicles. On MR images, the mass was intensely enhanced after contrast administration.

Among the masses of temporal bone associated with pulsatile tinnitus, the paragangliomas are the most common and easy to be diagnosed by their imaging features. While the other masses of temporal bone are uncommon, they could also be diagnosed accurately by clinical and imaging characteristics.