Interactive Web-based Learning Module on CT of the Temporal Bone: Anatomy and Pathology

Abstract

An interactive Web-based learning module on the temporal bone has been developed. It shows normal temporal bone anatomy in four imaging planes: axial, coronal, and parallel and perpendicular to the long axis of the petrous bone. After reviewing the normal anatomy, users should be able to identify key imaging features of pathologic conditions of the temporal bone. Children with congenital abnormalities of the temporal bone may present with conductive or sensorineural hearing loss or both and may have a genetic syndrome. Acute otitis media is the most common infection of the temporal bone and is most prevalent among children. Although imaging is unnecessary in uncomplicated otitis media, it is important for evaluation of infectious complications. Classically, temporal bone fractures were described as longitudinal or transverse with respect to the long axis of the petrous bone. However, it is increasingly recognized that many fractures have both longitudinal and transverse components. Patients with temporal bone fractures may have conductive or sensorineural hearing loss in addition to other complications. The most common tumor of the temporal bone at the cerebellopontine angle is the vestibular schwannoma. Paraganglioma is the second most common tumor of the temporal bone and the most common tumor of the middle ear. Supplemental material available at http://uwmsk.org/temporalbone/atlas.html.

Role of high resolution computed tomography in the evaluation of temporal bone lesions: our experience

“…3 On the other hand, MRI can image many soft tissue entities not visible by other techniques. 4 High resolution computed tomography (HRCT) is a modification of routine CT. It provides a direct visual window into the temporal bone and provides minute structural details of both anatomy and pathology of temporal bone.…”

Opacification of the middle ear and mastoid: imaging findings and clues to differential diagnosis

“…Areas of heterogeneity or low T2W signal can be seen due to haemosiderin deposition. MRI signal characteristics are identical to the petrous apex cholesterol granuloma, which usually exhibits more osseous expansion on CT. 3,8,31 The differential diagnosis includes conditions such as COM, cholesteatoma, glomus tympanicum tumour, and post-traumatic change. 2 COM, however, produces nonhaemorrhagic changes, cholesteatoma shows hypointense T1W signal, and a glomus tympanicum tumour shows avid contrast-enhancement.…”

“…The normal ossicular chain includes the highly recognizable "ice-cream cone" on axial CT images, consisting of the malleus head as the "ice cream" and the short process of the incus as the "cone". 3 In COM, tympanic membrane thickening and retraction is common, with possible erosions of the "cone", long process of the incus, and fibrous involvement of the incudostapedial joint producing apparent joint widening. 8 Common complications include post-inflammatory ossicular fixation with fibrous tissue fixation seen as added soft-tissue fibres; acquired cholesteatoma seen as added soft tissue producing ossicular and/or tympanic wall destruction; or tympanosclerosis appearing as tympanic ossification 24,27e29 (Figs 3b, 4aeb).…”

“…CE-MRI is well suited to assess rare complications, such as labyrinthitis, dural venous sinus thrombosis, intracranial abscess formation, or meningitis. 2,3,5 The differential diagnosis includes conditions such as a cholesteatoma or cholesterol granuloma. 2 Despite showing similar opacification, a cholesteatoma has high DWI (diffusion-weighted imaging) MRI signal, and a cholesterol granuloma shows high T1W change.…”

Accessible and Informative Sectioned Images, Color‐Coded Images, and Surface Models of the Ear

“…Human ear structures are hardly accessible by both cadaver dissection and microscopy; most learning tools for displaying the complex anatomy of the ear have been limited to plastic models for several decades. To escape this limitation, researchers have developed new learning tools, consisting of three‐dimensional (3D) models (Wang et al, , ; Li et al, ; Sorensen et al, ; Phillips et al, ). For that, basic image data were obtained by anatomists or clinicians, while software packages, on which the processed images are explored, were developed by computer engineers.…”