Post traumatic deafness: a pictorial review of CT and MRI findings

Abstract

Hearing loss is a common functional disorder after trauma, and radiologists should be aware of the ossicular, labyrinthine or brain lesions that may be responsible. After a trauma, use of a systematic approach to explore the main functional components of auditory pathways is essential. Conductive hearing loss is caused by the disruption of the conductive chain, which may be due to ossicular luxation or fracture. This pictorial review firstly describes the normal 2-D and 3-D anatomy of the ossicular chain, including the incudo-malleolar and incudo-stapedial joints. The role of 3-D CT in the post-traumatic evaluation of injury to the temporal bone is then evaluated. In the case of sensorineural hearing loss, CT can detect pneumolabyrinth and signs of perilymphatic fistulae but fails to detect subtle lesions within the inner ear, such as labyrinthine haemorrhage or localized brain axonal damage along central auditory pathways. The role that MRI with 3-D-FLAIR acquisition plays in the detection of inner ear haemorrhage and post-traumatic lesions of the brain parenchyma that may lead to auditory agnosia is also discussed.Key Points• The most common middle ear injuries are incudo-malleolar and incudo-stapedial joint luxation.• In patients with SNHL, CT can detect pneumolabyrinth or perilymphatic fistula• 3-D-FLAIR MRI appears the best sequence to highlight labyrinthine haemorrhage• Axonal damage and brain hematoma may lead to deafness

Traumatic dislocation of middle ear ossicles: A new computed tomography classification predicting hearing outcome

“…This is plausible because dislocation of the incus, which is embedded between the malleus and stapes, should affect both joints. Another plausible explanation for the lower prevalence of the often subtle incudostapedial dislocation in our CT-based study might be the initial hemotympanum, which makes an accurate radiologic assessment difficult, especially in early trauma diagnostics and for slight dislocations [ 20 , 24 ].…”

Imaging of Temporal Bone

“…In early development of CT, cochlear partitioning and soft tissue membranes were not adequately visualized (10) (11). Recent advances in MDCT, including the development of scanners with 32 detector rows (64 effective sections) for depiction of normal anatomy and pathologic states in the temporal bone, allow the acquisition of isotropic voxels that can be reconstructed and used in the multiplanar reconstructions of volumetric CT images (12). This technique gives radiologists the opportunity to visualize the anatomic structures of the middle and inner ears accurately (table 1) (13).…”

“…(6) (54) visualization of the cochlear partitioning (9). A recent paper by Maillot et al (12) indicated that MDCT allows radiologists to examine the complex anatomy of the temporal bone with sub-millimeter resolution and is the first modality of choice. Indeed, it is capable of revealing a broad spectrum of ossicular lesions that may not be apparent on the basis of clinical findings alone.…”

“…For MDCT the slice thickness is a critical point and detailed anatomical evaluation as small as 0.2 mm slice intervals have been used (12). The MDCT technique may help to overcome the limitations long imposed by restrictions in gantry angle and patient positioning and improves diagnostic accuracy.…”

CT Imaging Anatomy and Application in the Head and Neck

“…SFOF-VR can accurately locate the lesion and clearly show their relations, and thus provides more anatomic information for selecting optimal surgical path or treatment method. Furthermore, the combination of the technology and finite element modeling will have great effect on the study of regional anatomy, biomechanical analysis and surgical design [9,10].…”