High-Resolution CT Findings in Children with a Normal Pinna or Grade I Microtia and Unilateral Mild Stenosis of the External Auditory Canal

Abnormal orientation of the handle of the malleus in a 4-year-old girl with right-sided CHL (patient 6). Axial HRCT of the temporal bone, superior-to-inferior. A and B, Superior image shows a normal ossicular position. Inferiorly, abnormal orientation of the handle of the right malleus along with posterior fixation of the handle of the malleus (arrow) is present. There is asymmetric widening of the distance between the cochlear promontory (arrowhead) and the handle of the malleus. C and D, Normal ossicular anatomy is present superiorly. Inferiorly, normal orientation of the handle of the left malleus and a normal distance from the promontory to the handle (between arrows) are seen.

Abnormal fixation of the handle of the malleus along with increased distance of the handle of malleus to the cochlear promontory in a 4-year-old boy with right-sided CHL (patient 9). Axial HRCT of the temporal bones, superior-to-inferior. A and B, There is abnormal fusion of the right malleus and incus (long arrow) superiorly. The inferior image shows fixation of the handle of the malleus anteriorly (short arrow). Note an increased distance of the handle of the malleus to the cochlear promontory (arrowhead). C and D, Normal separation of the left ossicles is present superiorly. Inferiorly, there is a normal distance of the handle of the left malleus to the promontory in the normal ear (between arrows).

Abnormal fixation of the incus in a 5-year-old girl with left-sided CHL (patient 1). Axial HRCT of the temporal bone, superior-to-inferior. A and B, Superiorly, there is a normal incus with articulation with the stapes (arrow). Inferior image shows a normal long process of the incus with no fixation bar (arrow). C and D, Superiorly, there is fusion of the left malleus and incus (arrow). Inferior image shows a posterior fixation bar extending from the long process of the incus (long arrow) to the posterior wall of the tympanic cavity.

Abnormal asymmetric increased in the incudostapedial angle in a 3-year-old boy with right-sided CHL (patient 8). Coronal-reconstruction HRCT of the temporal bone at the level of the long process of the incus. A, An abnormally increased incudostapedial angle (arrow) measuring 109° is present in the right ear. B, The normal left ear has an incudostapedial angle measuring 93° (arrow).

Asymmetric narrowing of the Prussak space in a 12-year-old boy with left-sided CHL (patient 2). Coronal-reconstruction HRCT of the temporal bone at the level of the malleus. A, Normal appearance of the Prussak space in the normal right ear (arrow) is present. B, Asymmetric narrowing of the Prussak space (arrow) in the affected left ear is present with a normal volume of the tympanic cavity.