[Observation of foramina hypoplasia within internal auditory canal fundus with CT virtual endoscopy]

To observe normal and abnormal findings of foramina within internal auditory canal (IAC) fundus with Virtual Endoscopy of multisection helical Computed Tomography.

CT scanning of temporal bone was undergone in 25 volunteers (50 ears) in the normal group, in 8 cases (13 ears) with foramina hypoplasia within IAC fundus which were shown on CT and MRI images. CT virtual endoscopy (CTVE) findings were observed in the normal and abnormal groups. The lower threshold value was 900-1200 HU, the upper value was 3,071 HU in CTVE definitions.

The shape and position of foramina within IAC fundus were shown on the CTVE image, 50 foramina within IAC fundus were shown in all normal cases. In abnormal group, 9 ears were shown as IAC fundus disorder and foramina absent, only 1 foramina was shown in 1 ear, 2 foramen in 4 ears, 3 foramen in 2 ears, 4 foramen in 2 ears; Abnormal shape of cochlear nerve foramina was seen in 4 ears. Other malformations were also shown, including IAC malformations in 3 ears and inner ear malformations in 8 ears.

CTVE is useful to show the shape and position of normal foramina and pathological changes in the patients with foramina hypoplasia within IAC fundus.