Temporal Bone CT Images Research Articles

Atlas-Based Segmentation of Temporal Bone Anatomy.

To develop a time-efficient automated segmentation approach that could identify critical structures in the temporal bone for visual enhancement and use in surgical simulation software. An atlas-based segmentation approach was developed to segment the cochlea, ossicles, semicircular canals (SCCs), and facial nerve in normal temporal bone CT images. This approach was tested in images of 26 cadaver bones (13 left, 13 right). The results of the automated segmentation were compared to manual segmentation visually and using DICE metric, average Hausdorff distance, and volume similarity. The DICE metrics were greater than 0.8 for the cochlea, malleus, incus, and the SCCs combined. It was slightly lower for the facial nerve. The average Hausdorff distance was less than one voxel for all structures, and the volume similarity was 0.86 or greater for all structures except the stapes. The atlas-based approach with rigid body registration of the otic capsule was successful in segmenting critical structures of temporal bone anatomy for use in surgical simulation software.

Clinical Characteristics of Epidermoid Cysts of the External Auditory Canal.

Background and ObjectivesThe epidermoid cyst is a common benign disease of the skin caused by inflammation of hair cortex follicles and proliferation of epidermal cells within the dermis or superficial subcutaneous tissue. The purpose of this study was to investigate the characteristics of epidermoid cysts of the external auditory canal (EAC) by analyzing the clinical and radiologic features.Subjects and MethodsThe clinical records were retrospectively reviewed for patients diagnosed with epidermoid cyst of the EAC from March 2004 to December 2013. The epidermoid cysts were diagnosed clinically by endoscopy and microscopy examinations and by temporal bone CT images, and were confirmed by histopathologic examination. Characteristics of epidermoid cysts in bony EAC and cartilaginous EAC were compared.ResultsEight patients had an epidermoid cyst in the bony EAC and nine patients had one in the cartilaginous EAC. Swelling and otalgia were common symptoms, but 47% of cysts were found incidentally. The mean age of patients was 49.6 years (age range, 26-67 years) in the bony EAC cases and 26.1 years (age range, 6-57 years) in the cartilaginous EAC cases. The mean size of the epidermoid cyst was 3.50 mm (size range, 2-7 mm) in the bony EAC cases and 9.55 mm (size range, 2-20 mm) in the cartilaginous EAC cases.ConclusionsComparison of epidermoid cysts of the bony EAC and the cartilaginous EAC revealed that epidermoid cysts of the bony EAC is usually found incidentally, arose in older patients and had smaller size.

Temporal Bone CT: Improved Image Quality and Potential for Decreased Radiation Dose Using an Ultra-High-Resolution Scan Mode with an Iterative Reconstruction Algorithm.

Radiation dose in temporal bone CT imaging can be high due to the requirement of high spatial resolution. In this study, we assessed whether CT imaging of the temporal bone by using an ultra-high-resolution scan mode combined with iterative reconstruction provides higher spatial resolution and lower image noise than a z-axis ultra-high-resolution mode. Patients with baseline temporal bone CT scans acquired by using a z-axis ultra-high-resolution protocol and a follow-up scan by using the ultra-high-resolution-iterative reconstruction technique were identified. Images of left and right temporal bones were reconstructed in the axial, coronal, and Poschl planes. Three neuroradiologists assessed the spatial resolution of the following structures: round and oval windows, incudomallear and incudostapedial joints, basal turn spiral lamina, and scutum. The paired z-axis ultra-high-resolution and ultra-high-resolution-iterative reconstruction images were displayed side by side in random order, with readers blinded to the imaging protocol. Image noise was compared in ROIs over the posterior fossa. We identified 8 patients, yielding 16 sets of temporal bone images (left and right). Three sets were excluded because the patient underwent surgery between the 2 examinations. Spatial resolution was comparable (Poschl) or slightly better (axial and coronal planes) with ultra-high-resolution-iterative reconstruction than with z-axis ultra-high-resolution. A paired t test indicated that noise was significantly lower with ultra-high-resolution-iterative reconstruction than with z-axis ultra-high-resolution (P < .001), with a mean noise reduction of 37% (range, 18%-49%). The ultra-high-resolution-iterative reconstruction scan mode has similar or slightly better resolution relative to the z-axis ultra-high-resolution mode for CT of the temporal bone but significantly (P < .01) lower image noise, which may enable the dose to be reduced by approximately 50%.

Hearing loss in osteogenesis imperfecta patients

Osteogenesis imperfecta (OI) is an inherited bone and connective tissue disorder associated with the lifelong occurrence of frequent fractures following even mild trauma. Hearing loss is frequently reported in patients with OI. Objective: to examine the ratio of hearing loss in children with OI, and the relationship between audiological findings and CT images of temporal bone in children with OI. Subject and methods: forty – two children aged 5 to 17 years with OI were included in the study. The patients have type A of tympano and were mesured thresold of hearing by play audiometry. CT imaging was performed in 8 cases as well. Imaging abnormalities were correlated with clinical phenotypes and severity of hearing loss deduced from audiograms. Results: Hearing loss of all etiologies was observed in 28.05 % of ears in studied OI patients. Sensorineural and mixed hearing loss was observed in 4.88% and conductive hearing loss was detected in 23.17% of ears. CT revealed bone – bridge image in the middle ear (10/16 ears), hypodense foci in the fissula ante fenestram (4/16 ears) and cochlear (2/16 ears), abnormal stape ( 5/16 ears). Conclusions: hearing loss in children with osteogenesis imperfecta is quite frequent. We have all type of hearing loss, but the conductive of hearing loss have highest ratio. The site of abnormal on temporal bone CT images in OI corresponds to presence and type of hearing loss determined by audiometry.

Radiological prevalence of superior and posterior semicircular canal dehiscence in children

ObjectiveEstablishing the prevalence of semicircular canal dehiscence in a pediatric population using temporal bone CT imaging. Study designRetrospective analysis of all temporal bone CT scans during a 5-year period (2007–2012). MethodsCT scan images were reformatted in the plane of the canals and assessed by two independent reviewers with a third to resolve disagreement. Detailed chart review was performed for those found to have dehiscence. Superior and posterior canals were classified as “dehiscent”, “possibly dehiscent”, “thin” or “normal” for each case. Results649 temporal bones were assessed from 334 children (under 18 years of age). The prevalence rate of superior canal dehiscence (SCD) was 1.7% (3.3% of individuals). Posterior canal dehiscence (PCD) was present in 1.2% (2.1% of individuals). There were no cases of bilateral SCD, and one case of bilateral PCD. Age under 3 years was associated with a higher prevalence of thinning but not dehiscence. Congenital inner ear malformation was not related to a higher probability of dehiscence. The superior petrosal sinus was associated with the SCD in three cases (27.3%). Retrospective chart review highlighted possible vestibular symptoms in 3/11 patients with SCD (27.3%). ConclusionsThis forms the largest pediatric study of canal dehiscence to date. This study's prevalence rate is significantly lower than previous reports. The identified association with overlying venous structures may reflect the etiological process involved. The occurrence in children supports the hypothesis of a congenital predisposition for development of canal dehiscence syndrome.

Standardization of CT depiction of cochlear implant insertion depth.

Imaging a cochlear implant with CT is challenging because of implant-induced artifacts, anatomic cochlear variations, and lack of standard terminology for cochlear anatomy. The purposes of this project were to determine whether the cochlear implant tip was more accurately located on oblique CT reformations than on standard images, to review radiology reports for accurate cochlear implant locations, and to assess agreement between an implant surgeon and neuroradiologist by using standardized cochlear anatomy terminology for cochlear implant depth. In this retrospective study, a neuroradiologist and an implant surgeon independently viewed temporal bone CT images of 36 ears with cochlear implants. Direct axial images, standard coronal reformations, and oblique reformations parallel to the cochlea were compared to determine implant tip location, which was described by using a proposed standardized quadrant terminology. Implant locations were compared with the initial formal report generated by the original interpreting neuroradiologist. Thirty-six temporal bones with cochlear implants underwent CT interpretation for implant location. Interobserver agreement was similar when comparing cochlear implant tip location by using a quadrant nomenclature on axial and coronal images and on oblique reformations. Clinical radiology reports all were imprecise and ambiguous in describing the location of the cochlear implant tip. Accurate determination of insertion depth of the cochlear implant array can be determined by assessment of the implant tip on axial, coronal, and oblique CT images, but description of the tip location can be inaccurate due to lack of standardized terminology. We propose using a standardized terminology to communicate tip location by using the round window as the zero reference and quadrant numbering to describe cochlear turns. This results in improvement in radiology report accuracy and consistency regarding the cochlear implant insertion depth.

Semicircular canal dehiscence: Frequency and distribution on temporal bone CT and its relationship with the clinical outcomes

PurposeIn this study, we aimed to investigate the frequency of SCD and its distribution and relationship with clinical outcomes on thin-section CT of the temporal bone. Materials and methodsDigital temporal bone CT images of 850 consecutive patients (1700 temporal bone CTs, 5100 SCs) who presented with a range of complaints such as vertigo, deafness, ear pain, fullness, and discharge between January 2008 and December 2011 were re-evaluated. Axial and oblique coronal reconstruction images of the temporal bone were made with a reconstruction thickness of 0.5mm. Additionally, superior SC was evaluated in two perpendicular planes. ResultsOut of 850 patients, 70 had completely normal temporal bone CT. Ninety-three patients had at least one SCD. In the temporal bone-based evaluation, 119 (26 bilateral, 67 unilateral) of 1700 temporal bones (7%) showed dehiscence. The SC-based evaluation revealed 125 SCD (2.5%) in 5100 SCs. The total number and rates of SCD were as follows: superior 103 (82.4%), posterior 13 (10.4%), and lateral nine (7.2%). Twenty of the 93 patients with SCD (21.5%) revealed no other findings on their temporal bone CTs. We determined a significant correlation between vestibular complaints, conductive hearing loss and SCD but there was no correlation between mixed, sensorineural hearing loss and SCD. ConclusionWe determined the frequency of SCD in 11% of patients and 7% of temporal bones. With regards to the distribution, the superior SC showed the highest dehiscence rate (82.4%). We found a significant correlation between vestibular symptoms, conductive hearing loss and SCD.

Two Cases of Suspected Spontaneous Regression of Congenital Cholesteatoma in Children

We report two pediatric cases of suspected congenital cholesteatoma which the lesions spontaneously disappeared during the follow-up period. In case 1, a 3-year-old boy was examined by his local otolaryngologist because of an ear wax plug. In case 2, a 4-year-old girl was examined by her local otolaryngologist because of acute otitis media. In each case, a small whitish mass was found behind the ipsilateral anterior-superior-quadrant of the tympanic membrane, and the cases were referred to our hospital for further investigation. The children did not exhibit hearing loss or bone destruction in the middle ear. In both cases, the whitish mass gradually decreased in size during the follow-up period and disappeared under otomicroscopic examination. On the temporal bone CT images, a soft tissue mass anterior to the manubrium of the malleus also gradually decreased in size and disappeared. Based on these two cases, a “wait and watch” approach should be considered for patients with congenital cholesteatoma who do not exhibit hearing loss or bone destruction in the middle ear.

A Case of Breast Cancer Found from Recurrent Facial Palsy

We often come across cases of peripheral facial palsy, most of which can be cured with medication. We report herein on a case of breast cancer, found in a patient with recurrent facial palsy. A seventy-year-old female with facial palsy was cured once, but a few weeks later, facial palsy occurred again. We suspected a tumor as the cause of the recurrent facial palsy. We examined the patient with temporal bone CT and head MRI imaging and found a mass region with bone destruction on images of the temporal bone. When we did an excisional biopsy under general anesthesia, we unexpectedly identified the mass as a locally advanced breast cancer. Finally the patient was diagnosed as having a peripheral facial palsy caused by a metastatic tumor from breast cancer. Breast cancer associated with facial palsy is rare, but when the facial palsy recurs or occurs slowly, with facial spasm or with otitis media with effusion, we should consider the existence of a tumor, especially metastatic tumor from breast or lung cancer.

Inner ear anomalies seen on CT images in people with Down syndrome

Although dysplasia of inner ear structures in Down syndrome has been reported in several histopathological studies, the imaging findings have not been widely studied. To evaluate the prevalence and clinical significance of inner ear anomalies detected on CT images in patients with Down syndrome. The temporal bone CT images of patients with Down syndrome were assessed for inner ear anomalies; clinical notes and audiograms were reviewed for hearing loss. Logistic regression models were employed to identify which CT findings were associated with sensorineural hearing loss (SNHL). Inner ear anomalies were observed in 74.5% (38/51) of patients. Malformed bone islands of lateral semicircular canal (LSCC), narrow internal auditory canals (IACs), cochlear nerve canal stenoses, semicircular canal dehiscence (SCCD), and enlarged vestibular aqueducts were detected in 52.5% (53/101), 24.5% (25/102), 21.4% (21/98), 8.8% (9/102) and 2% (2/101) of patients' ears, respectively. IAC stenosis had the highest odds ratio (OR = 5.37, 95% CI: 1.0-28.9, P = 0.05) for SNHL. Inner ear anomalies occurred in 74.5% of our population, with malformed (<3mm) bone island of LSCC being the most common (52.5%) anomaly. Narrow IAC was seen in 24.5% of patients with Down syndrome and in 57.1% of ears with SNHL. High-resolution CT is a valuable for assessing the cause of hearing loss in people with Down syndrome.

CT imaging of superior semicircular canal dehiscence: Added value of reformatted images

Conclusion: Superior semicircular canal dehiscence (SSCD) syndrome may present with various symptoms. CT scans previously interpreted as normal may show SSCD, especially if special reconstructions tailored for superior canal evaluation are added. Objectives: The purpose of this study was to investigate prevalence of SSCD, its length and its correlation with symptoms in patients who had previously undergone temporal bone CT examination that was reported normal and to demonstrate the importance of reformatted images in the diagnosis of SSCD. Methods: We retrospectively reviewed 108 patients who had undergone temporal bone CT examination for various symptoms and were reported as normal. High-resolution temporal bone CT imaging was performed with 1 mm slice thickness in the transverse plane. Each of the superior semicircular canals was evaluated in the plane of Pöschl and Stenver reformatted images together with axial images. Results: Ninety-three patients were included in the study. Nineteen patients with semicircular canal dehiscence were detected. The mean age of the study group was 45 years. Radiologic evidence of SSCD occurred in 23 of 186 temporal bones with a radiologic prevalence of 12%. The most common symptoms in dehiscent patients were vertigo, hearing loss and tinnitus. Defect lengths varied between 1 mm and 6.5 mm.

Demineralization of the Otic Capsule in Otosclerosis (Otospongiosis)

A 34-year old Filipina presents with bilateral progressive hearing loss and tinnitus of three years' duration. Otologic examination reveals normal external auditory canals and tympanic membranes, with good tympanic membrane mobility on pneumatic otoscopy. Standard audiometric examination shows a bilateral moderate conductive hearing loss. Temporal bone CT imaging reveals the presence of a focal region of bone demineralization involving the dense bone of the otic capsule surrounding the cochlear lumen (Figure 1), a finding consistent with a diagnosis of active otospongiosis.&nbsp; The diagnosis was confirmed by visualization of an otosclerotic focus during transcanal middle ear exploration, where stapedectomy with placement of a stainless steel stapes prosthesis was performed. Otosclerosis is a condition unique to the temporal bone characterized by abnormal resorption and deposition of bone in the otic capsule and ossicles. Although it occurs more rarely in Asiatic populations compared to Europeans, Americans of Caucasian origin and Indians, it must be considered in patients presenting with primarily conductive hearing loss, especially if there is bilateral involvement. CT imaging of the temporal bone may help to differentiate this condition from other causes of conductive hearing loss, such as tympanosclerosis and bony epitympanic fixation of the ossicular chain from chronic infection and inflammation of the middle ear. One must be cognizant of the fact that a normal temporal bone CT scan does not rule a diagnosis of otosclerosis, because an inactive, highly sclerotic focus that appears as a uniform hyperdense mass may be difficult to distinguish from the normal compact labyrinth capsule (1). Other causes of otic capsule demineralization include osteogenesis imperfecta, Paget disease, otosyphilis, and Camurati-Engelmann disease. These may be differentiated by their individually characteristic patterns of bone involvement and evidence of disease in other organ systems.2 &nbsp

Demineralization of the Otic Capsule in Otosclerosis (Otospongiosis)

A 34-year old Filipina presents with bilateral progressive hearing loss and tinnitus of three years' duration. Otologic examination reveals normal external auditory canals and tympanic membranes, with good tympanic membrane mobility on pneumatic otoscopy. Standard audiometric examination shows a bilateral moderate conductive hearing loss. Temporal bone CT imaging reveals the presence of a focal region of bone demineralization involving the dense bone of the otic capsule surrounding the cochlear lumen (Figure 1), a finding consistent with a diagnosis of active otospongiosis. The diagnosis was confirmed by visualization of an otosclerotic focus during transcanal middle ear exploration, where stapedectomy with placement of a stainless steel stapes prosthesis was performed.&#x0D; Otosclerosis is a condition unique to the temporal bone characterized by abnormal resorption and deposition of bone in the otic capsule and ossicles. Although it occurs more rarely in Asiatic populations compared to Europeans, Americans of Caucasian origin and Indians, it must be considered in patients presenting with primarily conductive hearing loss, especially if there is bilateral involvement. CT imaging of the temporal bone may help to differentiate this condition from other causes of conductive hearing loss, such as tympanosclerosis and bony epitympanic fixation of the ossicular chain from chronic infection and inflammation of the middle ear. One must be cognizant of the fact that a normal temporal bone CT scan does not rule a diagnosis of otosclerosis, because an inactive, highly sclerotic focus that appears as a uniform hyperdense mass may be difficult to distinguish from the normal compact labyrinth capsule (1). Other causes of otic capsule demineralization include osteogenesis imperfecta, Paget disease, otosyphilis, and Camurati-Engelmann disease. These may be differentiated by their individually characteristic patterns of bone involvement and evidence of disease in other organ systems.2&#x0D;

Imaging correlation of children with DFNB1 vs non-DFNB1 hearing loss

Objectives To evaluate temporal bone CT findings in GJB2-related deafness (DFNB1) hearing loss and non-DFNB1 hearing loss children. Study Design Case-control series. Subjects and Methods Children with nonsyndromic hearing loss diagnosed as DFNB1 or non-DFNB1 after screening GJB2 allele variants and the large GJB6 deletion. Temporal bone CT images compared in a cohort of nine DFNB1 children with 10 non-DFNB1 children. Visual criteria and absolute measurements were compared against established normative values. Results Visual inspection failed to identify two patients with abnormalities identified by using absolute measurements. Only one of nine DFNB1 children had an ear anomaly versus seven of 10 non-DFNB1 (odds ratio 16.33; 95% CI, 1.35, 197.78; P = 0.050). The non-DFNB1 group had a mean vestibule width that was significantly larger, and a mean lateral semicircular canal island width and vestibular aqueduct that were significantly smaller than the DFNB1 group. Conclusions Visual inspection of temporal bone CT images alone may not identify all anomalies and should be used with absolute CT measurements. Abnormal temporal bone CT findings are significantly less likely in children with DFNB1 compared with non-DFNB1 children despite similar age and degree of hearing loss.

&lt;i&gt;Pneumolabyrinth&lt;/i&gt;: Radiologic Evidence of Labyrinthine Injury

A U.S. serviceman presented with a three month history of unsteadiness on ambulation and increasing episodes of vertigo whenever he turned his head rapidly to the right. He had previously been injured in a bomb blast while stationed in Iraq four months prior to consultation. Aside from multiple soft tissue and bone trauma, he had also experienced vertigo and nearly complete deafness in the right ear immediately after the blast. Medical records indicated the presence of a traumatic perforation of the right tympanic membrane and spontaneous nystagmus on initial emergency medical assessment after the incident. Physical examination on consultation revealed bilaterally intact eardrums, a positive right head impulse test, and a normal Romberg test. Audiometry showed a severe right SNHL. A presumptive diagnosis of a persistent perilymph fistula secondary to inner ear barotrauma was entertained, and supported by findings on temporal bone CT imaging. Figure 1 is the axial CT image of the patient's inner ear at the level of the basal turn of the cochlea. Two linear lucencies are visible within the cochlea (arrowheads). These have the same signal characteristics as the normal external auditory canal and middle ear space. As such, they indicate the presence of air within the cochlea – a condition termed pneumolabyrinth. Figure 2 shows a normal cochlea at the same level for comparison. Note the uniform soft tissue density within the cochlear lumen, representing the endocochlear fluids. The lucency in the round window niche (thin arrow) also represents air, but this is a normal finding. &nbsp; Barotrauma from blast injuries and traumatic tympanic membrane perforations may cause perilymph fistulas. This is probably due to a sudden pressure wave transmitted through the tympanic membrane that results in an inward rupture of the round window membrane or an inward displacement of the stapedial footplate.1 Pneumolabyrinth has been identified in patients suffering from perilymph fistulas due to barotraumas,2 and therefore can bolster the diagnosis when identified in the appropriate clinical setting. It has also been identified in patients with perilymph fistulas from other causes, including iatrogenic stapes fractures during mastoid surgery, temporal bone fractures, cholesteatoma, neoplasms of the temporal bone, stapedectomy, and after cochlear implantation.3

Pseudocolor transformation for visualization of ossicles in CT images

Conclusion. Pseudocolor transformation demonstrated partial efficiency for increasing the visibility of the stapes and the incudostapedial (IS) joint in CT images. Variable color transformation could be examined in the future for increasing detection of otologic lesions. Objectives. Pseudocolor transformation is a technique for artificially assigning colors to a gray scale. This study was undertaken to evaluate the efficiency of the pseudocolor transformation technique for the visualization of ossicles in temporal bone CT images. Subjects and methods. Twenty CT studies of healthy ears were reviewed. CT images were transformed to pseudocolor (rainbow scale) with Image-Pro Plus 4.0. software and compared with plain images using the following rating scale. For each image one of five scores concerning the visibility of the stapes and IS joint was given: 1, not seen; 2, probably not seen; 3, not sure; 4, probably seen; 5, definitely seen. Visualization sensitivity was determined through statistical analysis using a paired t test. Results. The stapes and IS joint were more easily identifiable in pseudocolor-transformed images compared with plain images (p<0.05). The oval window and footplate were both more easily distinguishable in pseudocolor-transformed images compared with plain images (p<0.05).

Computed tomography findings in large vestibular aqueduct syndrome

Conclusions. Patients with large vestibular aqueduct syndrome (LVAS) have disturbed morphogenesis of bony labyrinth. Semicircular canal anomalies are common in LVAS. Objective. To describe the additional inner ear anomalies on CT imaging in pediatric patients with LVAS, and to investigate the lateral semicircular canal (LSCC) anomalies associated with LVAS by measurement of the LSCC bony island width. Patients and methods. We retrospectively reviewed the digitally stored temporal bone CT imaging obtained for 23 patients with LVAS, additional inner ear anomalies were noted, and measurements of the LSCC bony island width were made on axial CT scans on the workstation. Measurements were compared to the normative data obtained from 20 patients without sensorineural hearing loss. Results. Of the 23 patients (bilateral in 22 and unilateral in 1), additional inner ear malformations were identified in 21 cases presenting either singly or in combination. A small LSCC bony island (<3 mm in diameter) appeared highly typical; vestibule and LSCC anomalies were identified in 13 cases (26 ears) based on visual inspection combined with abnormal measurements. Dehiscence of the superior and/or posterior semicircular canal was identified in 19 ears, and Mondini deformity was identified in 6 ears.

Pneumolabyrinth: Radiologic Evidence of Labyrinthine Injury

A U.S. serviceman presented with a three month history of unsteadiness on ambulation and increasing episodes of vertigo whenever he turned his head rapidly to the right. He had previously been injured in a bomb blast while stationed in Iraq four months prior to consultation. Aside from multiple soft tissue and bone trauma, he had also experienced vertigo and nearly complete deafness in the right ear immediately after the blast. Medical records indicated the presence of a traumatic perforation of the right tympanic membrane and spontaneous nystagmus on initial emergency medical assessment after the incident. Physical examination on consultation revealed bilaterally intact eardrums, a positive right head impulse test, and a normal Romberg test. Audiometry showed a severe right SNHL. A presumptive diagnosis of a persistent perilymph fistula secondary to inner ear barotrauma was entertained, and supported by findings on temporal bone CT imaging.&#x0D; Figure 1 is the axial CT image of the patient's inner ear at the level of the basal turn of the cochlea. Two linear lucencies are visible within the cochlea (arrowheads). These have the same signal characteristics as the normal external auditory canal and middle ear space. As such, they indicate the presence of air within the cochlea – a condition termed pneumolabyrinth. Figure 2 shows a normal cochlea at the same level for comparison. Note the uniform soft tissue density within the cochlear lumen, representing the endocochlear fluids. The lucency in the round window niche (thin arrow) also represents air, but this is a normal finding.&#x0D; &#x0D; Barotrauma from blast injuries and traumatic tympanic membrane perforations may cause perilymph fistulas. This is probably due to a sudden pressure wave transmitted through the tympanic membrane that results in an inward rupture of the round window membrane or an inward displacement of the stapedial footplate.1 Pneumolabyrinth has been identified in patients suffering from perilymph fistulas due to barotraumas,2 and therefore can bolster the diagnosis when identified in the appropriate clinical setting. It has also been identified in patients with perilymph fistulas from other causes, including iatrogenic stapes fractures during mastoid surgery, temporal bone fractures, cholesteatoma, neoplasms of the temporal bone, stapedectomy, and after cochlear implantation.3

Relationship between the external aperture and hearing loss in large vestibular aqueduct syndrome

Large vestibular aqueduct syndrome (LVAS) is a major cause of hearing loss in childhood. This study aimed at measuring external aperture of enlargement of the vestibular aqueduct (EVA) and analyzing relationship between the size of external aperture and hearing loss. Diagnostic criteria of LVAS were based on hearing loss and CT images. CT images of temporal bone of 100 LVAS patients were collected and 60 control subjects were reviewed retrospectively in the past 10 years. A battery of audiometric and vestibular function tests were performed. The width of the vestibular aqueduct (VA) was measured on axial CT images of the temporal bone. One hundred patients (65 men, 35 women) were diagnosed as having the isolated EVA. Hearing loss mostly occurred in early childhood. The diagnosis age of LVAS was 7.7 years on average. The causes of hearing loss could not be confirmed by initial consult. Typically, audiometric curve is the high-frequency down-sloping configuration. 92% of the cases had severe or profound sonsorineural hearing loss (SNHL). The mean size of the external aperture was (7.5 +/- 1.2) mm in present LVAS. Statistical analysis showed that the degree of hearing loss is unrelated to the width of VA. LVAS is a distinct clinical entity characterized by fluctuating, progressive SNHL. The degree of hearing loss is unrelated to the size of external aperture of VA. The protective management and hearing aid have become the main therapies. The cochlear implantation might be performed if the hearing loss affected learning at school.

Clinical characteristics of so called eosinophilic otitis media

Objective: Although ‘eosinophilic otitis media’ is not as uncommon a condition as was previously believed, its cause and pathogenesis are not yet fully understood. The purpose of this study was to describe the clinical characteristics in patients with ‘eosinophilic otitis media’ to clarify its pathogenesis. Methods: Seven adult patients with persistent and intractable otitis media with viscous middle ear effusion containing many eosinophils, who were also under treatment for bronchial asthma, were studied. The following examinations were conducted: nasopharyngeal endoscopy, pure-tone audiometry, eustachian tube function test, temporal bone CT scan, blood analysis, bacterial and fungal culture of middle ear effusion, histological study of the middle ear and nasal specimens, and measurement of eosinophilic cationic protein (ECP) in middle ear effusion. Results: Some patients had persistent perforation with papillomatous granulation tissue arising from the mesotympanic mucosa, and all the patients had nasal polyposis. The pure-tone audiometry showed the mixed-type of hearing loss in all the patients, and the hearing level deteriorated progressively during the course in some patients. The eustachian tube function was not always poor but was patulous in some cases. The most severely diseased areas were in the eustachian tube and mesotympanum by temporal bone CT images. All the seven patients had the high levels of total serum IgE, but the RAST scores were negative in three patients and low grade in three patients. The accumulation of eosinophils was observed in middle ear effusion, middle ear mucosa and nasal polyps, and the eosinophils were highly activated with degranulation. High level of ECP was also recovered from middle ear effusion. Conclusions: Active eosinophilic inflammation occurs in the entire respiratory tract, including the middle ear in these patients. From our present investigation, we propose the criteria and clinical characteristics of ‘eosinophilic otitis media’.