Computerized Tomography in Hearing Loss and DIsequilibrium States

1981 ◽  
Vol 89 (5) ◽  
pp. 861-866 ◽  
Author(s):  
William N. Hanafee
Keyword(s):  
Hearing Loss ◽  
Contrast Agent ◽  
Inner Ear ◽  
Computerized Tomography ◽  
Semicircular Canal ◽  
Internal Auditory Canal ◽  
Ct Scanning ◽  
Ct Scans ◽  
Horizontal Semicircular Canal

Computerized tomographic (CT) scanning for intracanalicular tumors requires air as a contrast agent within the internal auditory canal and special computer manipulations of the image to visualize small tumors. The same computer manipulations of CT scans provide detail of the middle and inner ear structures not available by non-CT tomographic techniques. The demonstration of horizontal semicircular canal fistula is one area in which CT scanning is clearly superior. Some pitfalls of the technique and interpretation of it will be discussed.

scholarly journals Unilateral Horizontal Semicircular Canal Malformation Causing Recurrent Vertigo

2018 ◽  
Vol 32 (2) ◽  
pp. 58-59
Author(s):  
Nathaniel W. Yang
Keyword(s):  
Hearing Loss ◽  
Inner Ear ◽  
Temporal Bone ◽  
Semicircular Canal ◽  
Lateral Semicircular Canal ◽  
Vestibular Loss ◽  
Vestibular Neurectomy ◽  
Horizontal Semicircular Canal ◽  
Ear Malformations ◽  
Vestibular Symptoms

A 62-year-old man consulted for recurrent episodes of vertigo lasting from seconds to several minutes. The vertigo was variably described as spinning, lateral swaying, and a feeling of being “unsure of his position in space.” These episodes were noted to have begun when the patient was still in his 20’s. Standard pure tone audiometry revealed a mild-to-moderate downsloping mixed hearing loss in the left ear. Bithermal caloric testing indicated the presence of a significant left-sided peripheral vestibular loss. Due to the fact that the vertigo episodes presented relatively early in life, the possibility of a congenital inner ear malformation was considered as a cause for his symptoms.  Computerized tomographic (CT) imaging of the temporal bone was performed. This clearly showed the left horizontal semicircular canal lacking a central bony island. (Figure 1 and 2) The cochlea, superior and posterior semicircular canals, vestibular and cochlear aqueducts, and ossicular chain were grossly normal. A malformation of the horizontal or lateral semicircular canal is one of the most common inner ear malformations, as it is the last vestibular structure to be formed during inner ear embryogenesis. As such, it may occur in isolation or may be associated with other vestibular, cochlear, or middle ear malformations.1,2  Although vertigo and dizziness are symptoms to be expected in such a condition, existing data indicates that it may be totally asymptomatic, or it may also present as a sensorineural, conductive, or mixed type of hearing loss.1,3   Radiologic imaging is of prime importance in diagnosing such conditions, especially when auditory and/or vestibular symptoms manifest early in life. This case perfectly illustrates the need for such studies, as the patient went undiagnosed for more than forty years!             No definitive statements can be gleaned from existing medical literature with respect to treatment. However, in patients with debilitating vestibular symptoms, management with modalities that selectively target the vestibular system, but spare the auditory system, such as vestibular neurectomy and trans-tympanic aminoglycoside therapy appear to be reasonable options.   References   Johnson J, Lalwani AK. Sensorineural and conductive hearing loss associated with lateral semicircular canal malformation. Laryngoscope 2000 Oct;110(10):1673–1679. DOI:10.1097/00005537-200010000-00019 PMID: 11037823   Casselman JW, Delanote J, Kuhweide R, van Dinther J, De Foer B, Offeciers EF. Congenital malformations of the temporal bone. In: Lemmerling M, De Foer B, editors. Temporal bone imaging. Berlin Heidelberg: Springer-Verlag; 2015, pp. 120-154.   Kim CH, Shin JE, Lee YJ, Park HJ. Clinical characteristics of 7 patients with lateral semicircular canal dysplasia. Res Vestib Sci 2012;11(2):64-68.

scholarly journals Cochlear Nerve Canal Stenosis: Association With MYH14 and MYH9 Genes

2021 ◽  
pp. 014556132199683
Author(s):  
Wenqi Liang ◽  
Line Wang ◽  
Xinyu Song ◽  
Fenqi Gao ◽  
Pan Liu ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Next Generation Sequencing ◽  
Inner Ear ◽  
Internal Auditory Canal ◽  
Cochlear Nerve ◽  
Transverse Diameter ◽  
Congenital Hearing Loss ◽  
Canal Stenosis ◽  
Ear Anomalies ◽  
Generation Sequencing

The bony cochlear nerve canal transmits the cochlear nerve as it passes from the fundus of the internal auditory canal to the cochlea. Stenosis of the cochlear nerve canal, defined as a diameter less than 1.0 mm in transverse diameter, is associated with inner ear anomalies and severe to profound congenital hearing loss. We describe an 11-month-old infant with nonsyndromic congenital sensorineural hearing loss with cochlear nerve canal stenosis. Next-generation sequencing revealed heterozygous mutations in MYH9 and MYH14, encoding for the inner ear proteins myosin heavy chain IIA and IIC. The patient’s hearing was rehabilitated with bilateral cochlear implantation.

Hemostasis and computerized tomography in head injury

1981 ◽  
Vol 55 (5) ◽  
pp. 718-724 ◽  
Author(s):  
J. Jaap van der Sande ◽  
Jan J. Veltkamp ◽  
Ria J. Boekhout-Mussert ◽  
G. Jan Vielvoye
Keyword(s):  
Head Injury ◽  
Computerized Tomography ◽  
Degradation Product ◽  
Ct Scanning ◽  
Mass Effect ◽  
Ct Scans ◽  
Fibrinogen Degradation Product ◽  
Content Type ◽  
Study Results ◽  
Coagulation Study

✓ Coagulation studies (plasma fibrinogen, ethanol gelation test, and fibrin-fibrinogen degradation product concentration) and computerized tomography (CT) scan examinations were performed in 55 patients with blunt head injury. The frequency of abnormalities in both coagulation study results and CT scans was higher in patients with severe clinical features and clinical course than in less severely injured patients; in these same patients the coagulation results were abnormal (64%) more frequently than the CT scans (40%). Very high fibrin-fibrinogen degradation product (FDP) concentrations were found to be associated with combined hemorrhagic lesions and mass effect on CT scans, but not with a specific localization of braintissue damage. It was concluded that: 1) FDP concentration reflects the amount of brain-tissue damage rather than its location, and 2) in the absence of other possible causes of disseminated intravascular coagulation, coagulation studies may be more sensitive than CT scanning in demonstrating brain contusion.

Ménière Recognizes That Vertigo Can Originate from the Inner Ear

2016 ◽  
Author(s):  
Robert W. Baloh
Keyword(s):  
Hearing Loss ◽  
Inner Ear ◽  
Blood Vessels ◽  
Semicircular Canal ◽  
Semicircular Canals ◽  
Underlying Disease ◽  
The Brain ◽  
Benign Course

Prosper Ménière was the first clinician to conclude that vertigo can result from diseases of the inner ear. The symptom of vertigo originally fell under the rubric of apoplectiform cerebral congestion, a disorder thought to result from overfilling of blood vessels in the brain. Ménière noted that patients with vertigo and hearing loss associated with damage to the inner ear often have a benign course, and aggressive treatments such as bleeding can be more dangerous than the underlying disease. The first hint that the semicircular canals may be related to balance rather than hearing was provided by a Frenchman, Marie Jean Pierre Flourens. He systematically cut each semicircular canal in the pigeon and noted that the animal’s head and body tended to move in the plane of the damaged canal. The gyrations of the animals described by Flourens made Ménière think that vertigo in humans might be a similar phenomenon.

The significance for postoperative hearing of preserving the labyrinth in acoustic neurinoma surgery

1992 ◽  
Vol 77 (5) ◽  
pp. 677-684 ◽  
Author(s):  
Marcos Tatagiba ◽  
Madjid Samii ◽  
Cordula Matthies ◽  
Mowaffak El Azm ◽  
Robert Schonmayr
Keyword(s):  
Hearing Loss ◽  
Inner Ear ◽  
Semicircular Canal ◽  
Semicircular Canals ◽  
Cochlear Nerve ◽  
Acoustic Neurinoma ◽  
Content Type ◽  
Acoustic Neurinomas ◽  
A Prospective Study ◽  
Fine Print

✓ Among 186 patients with preoperative hearing, a total of 189 acoustic neurinomas were removed through a lateral suboccipital approach with anatomical preservation of the cochlear nerve. Functional hearing was preserved in 92 (49%) of these patients; despite anatomical preservation of the cochlear nerve, deafness was the result in 51 % of the series. Many factors have been considered to cause hearing loss in patients whose cochlear nerve was intact after surgery; these include nerve retraction, nerve or cochlear ischemia, overheating and vibration damage to the nerve, and opening of the labyrinth. To evaluate the significance of injury to the labyrinth in postoperative hearing loss, a prospective study was undertaken. High-resolution computerized tomography studies through the inner ear with bone algorithm were performed pre- and postoperatively. The postoperative status of the labyrinth was classified into three patterns: intact, fenestrated, and widely opened. Injury to the labyrinth occurred in 30% of the cases. The most frequently injured labyrinth structures were the crus commune of the posterior and superior semicircular canals (52%), the posterior semicircular canal (23%). the vestibule (21%), and the superior semicircular canal (4%). A statistically significant relationship was found between injury to the labyrinth and deafness, elevated thresholds, and lower discrimination values at pure-tone audiograms and speech audiometry (p < 0.0001). The degree of the injury (comparison between fenestration and wide opening of the labyrinth) was also significantly related to postoperative deafness (p < 0.0001). Disturbance of the inner-ear fluids was considered to be the cause of the hearing loss. In 12 patients labyrinth injury was not associated with deafness. This finding may support the existence of mechanisms of cochlear protection. The homeostatic function of the endolymphatic sac was considered to play an important role in recovery of damaged hearing in these 12 cases.

Enlarged vestibular aqueducts and other inner-ear abnormalities in patients with Down syndrome

2016 ◽  
Vol 131 (4) ◽  
pp. 298-302 ◽  
Author(s):  
C M Clark ◽  
H H Patel ◽  
S G Kanekar ◽  
H Isildak
Keyword(s):  
Computed Tomography ◽  
Hearing Loss ◽  
Down Syndrome ◽  
Sensorineural Hearing Loss ◽  
Inner Ear ◽  
Internal Auditory Canal ◽  
Sensorineural Hearing ◽  
Vestibular Aqueduct ◽  
Computed Tomography Images ◽  
Temporal Bones

AbstractBackground:Histopathological anomalies of inner-ear structures in individuals with Down syndrome have been well documented; however, few studies have examined the radiological features.Methods:A retrospective study was conducted of temporal bone computed tomography images in 38 individuals (75 ears) with Down syndrome to evaluate the prevalence of inner-ear abnormalities and assess vestibular aqueduct widths.Results:Inner-ear anomalies were identified in 20 of the 38 individuals (52.6 per cent). Seven of the 75 temporal bones (9.3 per cent) were found to have higher than previously reported. A dilated internal auditory canal and vestibule were more common among the present study group, while prior studies have demonstrated internal auditory canal stenosis and decreased vestibule size.Conclusion:Down syndrome patients exhibit a high prevalence of dysplastic inner-ear features that confer substantial risk of sensorineural hearing loss. Computed tomography is a useful screening aid to detect inner-ear abnormalities, particularly enlarged vestibular aqueducts, which cause preventable sensorineural hearing loss in this population.

CT-assisted stereotaxic aspiration of colloid cysts of the third ventricle

1985 ◽  
Vol 62 (2) ◽  
pp. 238-242 ◽  
Author(s):  
Juan J. Rivas ◽  
Ramiro D. Lobato
Keyword(s):  
Computerized Tomography ◽  
Third Ventricle ◽  
Ct Scanning ◽  
Ct Scans ◽  
Content Type ◽  
The Third ◽  
Colloid Cysts ◽  
Reproducible Method ◽  
Inner Diameter ◽  
Fine Print

✓ A technique is reported for the stereotaxic evacuation of colloid cysts of the third ventricle using a stereotaxic system adapted for computerized tomography (CT) scanning. This is an accurate, simple, and reproducible method that avoids the risks of direct approaches. Successful intracystic aspiration resulting in the cure of the patient may be difficult when the viscosity of the cyst contents is high. Thus, the authors use a large cannula (1.8 mm in inner diameter) to evacuate cysts that appear hyperdense on CT scans; these seem to contain a thicker colloid material than hypodense or isodense cysts.

The Singular Canal: A Valuable Landmark in Surgery of the Internal Auditory Canal

1988 ◽  
Vol 98 (2) ◽  
pp. 138-143 ◽  
Author(s):  
Herbert Silverstein ◽  
Horace Norrell ◽  
Eric Smouha ◽  
Thomas Haberkamp
Keyword(s):  
Hearing Loss ◽  
High Resolution ◽  
Sensorineural Hearing Loss ◽  
Semicircular Canal ◽  
Internal Auditory Canal ◽  
Retrosigmoid Approach ◽  
Posterior Semicircular Canal ◽  
Vestibular Neurectomy ◽  
Acoustic Neuromas ◽  
Acoustic Neuroma Surgery

The singular canal transmits the posterior ampullary nerve between the inferior part of the internal auditory canal (IAC) and ampulla of the posterior semicircular canal. The anatomy of the singular canal was studied in temporal bone dissections, in surgical dissections, and in high-resolution computerized tomography scans. Measurements were taken for distances between the origin of the singular canal in the IAC, the porus acousticus, the vestibule, and posterior canal ampulla. The location and importance of the singular canal are demonstrated for retrosigmoid-IAC vestibular neurectomy, retrosigmoid acoustic neuroma surgery, and transcochlear cochleovestibular neurectomy. The main purpose for the use of the retrosigmoid approach to the internal auditory canal during vestibular neurectomy and excision of acoustic neuromas is preservation of hearing. A major concern when the contents of the internal auditory canal are exposed through this approach is fenestration of the labyrinth, which results in sensorineural hearing loss. In the retrosigmoid approach, the singular canal has been found to be a vital landmark in prevention of fenestration during surgery of the internal auditory canal.

MR imaging features of an intracochlear acoustic schwannoma

1994 ◽  
Vol 108 (12) ◽  
pp. 1111-1114 ◽  
Author(s):  
Martin J. Donnelly ◽  
Carmel A. Daly ◽  
Robert J. S. Briggs
Keyword(s):  
Unusual Case ◽  
Internal Auditory Canal ◽  
Ct Scanning ◽  
Clinical Suspicion ◽  
Ct Scans ◽  
Imaging Features ◽  
Mri Features ◽  
Acoustic Schwannoma ◽  
Intracochlear Schwannoma ◽  
Transotic Approach

AbstractWe present a very unusual case of an acoustic neuroma involving the left cochlea and internal auditory canal of a 24-year-old man. Clinical suspicion was aroused when the patient presented with a left total sensorineural hearing loss and continuing vertigo. The diagnosis was made pre-operatively with MRI after initial CT scanning was normal. The tumour was removed via a transotic approach. This case report demonstrates the MRI features of an intracochlear schwannoma and emphasizes the importance of MRI in patients with significant auditory and clinical abnormalities with normal CT scans of the relevant region.

A new troodontid (Dinosauria, Theropoda) braincase from the Dinosaur Park Formation (Campanian) of Alberta

1993 ◽  
Vol 30 (10) ◽  
pp. 2231-2247 ◽  
Author(s):  
Philip J. Currie ◽  
Xi-Jin Zhao
Keyword(s):  
Inner Ear ◽  
Computerized Tomography ◽  
Middle Ear ◽  
Lateral Surface ◽  
Ct Scans ◽  
Internal Anatomy ◽  
New Information ◽  
Close Relationship ◽  
Dinosaur Park Formation ◽  
The Brain

A new, well-preserved specimen of Troodon formosus is the first to reveal the internal anatomy of the lower part of the braincase. In addition to providing new information on the brain of this highly encephalized dinosaur, the uncrushed bones clear up anatomical details left obscure by earlier studies. Computerized tomography (CT) scans reveal the nature of the inner ear and the course of the pneumatic ducts diverging from the middle ear. Evidence is presented to show that four of the five periotic pneumatic systems found in bird skulls are present in Troodon. The anterior tympanic recess is the most elaborate system, and diverticula from each side extend anteriorly, dorsally and, posteriorly from the middle ear. The posterior tympanic recess is located within the paroccipital process and the basioccipital, but the pneumatopore posterolateral to the stapedial recess is secondarily closed. The dorsal periotic sinus is represented by a smooth-surfaced concavity on the lateral surface of the prootic. The position of a pneumatic recess in this region is demonstrated by the presence of a pneumatopore in the quadrate. Diverticula from the anterior and posterior tympanic recesses are connected within braincase bones, and a possible pneumatopore in the prootic may connect these to the dorsal tympanic recess. The pneumatic condition of the troodontid articular is unknown. Contralateral connections of the sinus systems have been used to argue for a close relationship between birds and crocodiles, but their presence in this specimen suggests that they appeared more than once in archosaurs or that they are plesiomorphic for crocodiles, dinosaurs, and birds. Cranial pneumaticity cannot be used by itself to resolve the interrelationships of crocodiles, theropods, and birds, but other characters suggest derivation of birds from theropods.

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