Observation Of Foramina Within Internal Auditory Canal Fundus With CT Virtual Endoscopy

Objective: To find the optimal convolution kernel in reconstruction when observe the internal auditory canal fundus with CT virtual endoscopy. To observe normal and abnormal findings of foramina within internal auditory canal fundus with Virtual Endoscopy of multisection helical Computed Tomography.Materials and Methods: CT scanning of temporal bone was undergone in 50 volunteers (100 ears) without ear disease, Images of all cases were reconstructed with different convolution kernel. Compare the image of the foramina within internal auditory canal fundus with virtual endoscope by different convolution kernel in reconstruction. Observe normal findings of foramina within internal auditory canal fundus with Virtual Endoscope and choose the optimal convolution kernel in reconstruction Abnormal group 20 cases (25 ears), 13 cases of men and 7 women, aged 3-18 years old, are congenital sensorineural deafness patients all, and HRCT and MRI examination show the internal auditory canal fundus had developmental malformations. Observe the shape and position of the foramina nervosa with virtual endoscope by optimal convolution kernel in reconstruction,and show the dysplastic type of t the foramina within internal auditory canal fundus.Results:1. We can get the best image of the foramina within internal auditory canal fundus with virtual endoscope by B60 sharp and U70 very sharp kernel value in reconstruction.2. The shape and position of foramina within IAC fundus were shown on the CTVE image,5 foramina within IAC fundus were shown in all normal cases.3. In abnormal group, 9 ears were shown as IAC fundus disorder and foramina absent,only 1 foramen was shown in 1 ear; 2 foramina in 4 ears, one is foramen faciale,the other is syzygial nervus statoacusticus foramina ;3 foramina in 2 ears, one is foramen faciale, nervus statoacusticus foramen syzygy to 2 foramina; 4 foramina in 2 ears, both are clausura of cochlear nerve foramina; Abnormal shape of cochlear nerve foramina was seen in 16 ears, stegnosis of the foramina nervosa in 10 ears and the disappearance of modiolus in 6 ears. Other malformations were also shown, including IAC malformations in 3 ears and inner ear malformations in 8 ears. Dysplasia of cochlear nerve foramina was shown in all 25 ears of this group. Single cochlear nerve foramina hypoplasia was shown in 18 ears, stegnosis in 10 ears, CTVE shows the shape of helix of the cochlear nerve foramina disappeared; clausura of cochlear nerve foramina in 2 ears, CTVE shows no foramina nervosa on consecutive bony paries, the disappearance of modiolus in 6 ears, CTVE shows the absence of sclerotin in modiolus, the cavity of cochlear were shown. Absence of nervus statoacusticus foramina in 1 ears, nervus statoacusticus foramen syzygy to 1 foramina in 4 ears, nervus statoacusticus foramen syzygy to 2 foramina in 2 ears.Conclusions:1. We can get the best image of the foramina within internal auditory canal fundus with virtual endoscope by B60 sharp and U70 very sharp kernel value in reconstruction.2. CTVE is useful to volumetric display the shape, position and adjacent relationship of the 5 foramina within IAC fundus; the shape of helix of cochlear nerve foramina is shown in all normal ears.3. The dysplasia of the foramina within internal auditory canal fundus can be expressed as single foramen, two foramina, three foramina, four foramina or stegnosis and enlargement of the foramina nervosa.4. Cochlear nerve foramina without helix-like shape is a feature of CT virtual endoscope in the patient with hypoplasia of cochlear nerve foramina.