Internal Auditory Canal Diverticula among Pediatric Patients: Prevalence and Assessment for Hearing Loss and Anatomic Associations

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FIG 1.
Axial temporal bone CT image (A) at the level of the inferior aspect of the right internal auditory canal demonstrates the typical appearance of an internal auditory canal diverticulum (arrow). An image obtained at the same level in a different patient without an internal auditory canal diverticulum is provided for comparison (B).
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FIG 2.
Visual threshold developed after the initial review and applied during the subsequent review by the 4 neuroradiologist readers. The visual threshold consists of axial temporal bone CT images obtained in 4 different patients and is intended to depict the minimum contour irregularity necessary to be considered an internal auditory canal diverticulum (arrows) for the second review performed in this study.
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FIG 3.
Flow chart depicting the initial and subsequent image reviews.
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FIG 4.
Axial temporal bone CT images from 4 different patients depict representative examples of subtle IAC contour irregularities (arrows) determined during consensus review of discrepant cases to not reach the visual threshold necessary to be considered an IAC diverticulum.

Table 1:

Characteristics of the study group

Sex
Male	157 (55%)
Female	126 (45%)
Age
Mean (SD) (yr)	7.8 (4.8)
Minimum	6 weeks
Maximum	17 years
Audiogram (temporal bone sides)
Normal	152 (27%)
Sensorineural loss	158 (28%)
Mixed loss	39 (7%)
Conductive loss	112 (20%)
Unavailable	100 (18%)

Table 2:

Temporal bone CT findings within the study group

Individual Temporal Bones (Sides)
Internal auditory canal diverticulum
Yes	64 (11%)
No	497 (89%)
Enlarged vestibular aqueduct
Yes	43 (8%)
No	518 (92%)
Labyrinthine dysplasia
Yes	66 (12%)
No	495 (88%)
Cochlear cleft
Yes	205 (37%)
No	356 (63%)
Otospongiosis
Yes	2^{^a} (0.4%)
No	559 (99.6%)

Table 3:

Internal auditory canal diverticula association assessment

	Internal Auditory Canal Diverticulum		P
	Yes	No	P
Sex^{^a}
Male	28	129	.13
Female	14	112
Age (mean) (SD) (yr)	7.7 (5.0)	7.8 (4.8)	.91
Audiogram^{^b}
Normal hearing	20	132	.65
Hearing loss	36	273
Conductive	16	96	.86
Sensorineural	16	142	.48
Mixed	4	35	.79
Enlarged vestibular aqueduct^{^b}
Yes	2	41	.21
No	62	456
Labyrinthine dysplasia^{^b}
Yes	7	59	1.00
No	57	438
Cochlear cleft^{^b}
Yes	30	175	.07
No	34	322
Otospongiosis^{^b}
Yes	2	0	.013
No	62	497