CT and MRI for the diagnosis of perilymphatic fistula: a study of 17 surgically confirmed patients.

BACKGROUND: We evaluated the usefulness of CT and MRI for the diagnosis of perilymphatic fistula (PLF) of the round (RW) and/or oval (OW) windows, with surgery as gold standard. METHODS: We retrospectively enrolled 17 patients who presented a surgically confirmed PLF of the round (RW) or oval (OW) windows. All patients were imaged by CT + MRI (T2W SSFP without contrast) prior to surgery (= gold standard). Two radiologists, analyzed the RW and OW on the side of the clinical symptoms and sensitivity (Se) + Specificity (Sp) were calculated. RESULTS: Round window fistula was the most frequent (71%). The best sign of PLF on imaging was a fluid filling of the window niches, which had good Se (83-100% for RW, 66-83% for OW) and Sp (60% for RW, 91-100% for OW). Disorientation of the footplate and pneumolabyrinth were also only observed in 50% of OW PLF. CONCLUSION: The combination of CT and MRI is a reliable tool for a fast and accurate diagnosis of round and oval window perilymphatic fistula, with good sensitivity (> 80%). The most common sign of PLF on imaging is the presence of a fluid-filling in the RW (especially if > 2/3 of the RW niche) or in the OW niches on both CT and MRI. A disorientation of the footplate or the presence of a pneumolabyrinth are clearly in favor of an oval window perilymphatic fistula.

Case 226: Oval Window Atresia.

A 6-year-old girl presented with bilateral hearing loss. Her otologic, birth, and family histories were limited, given that she was adopted, but her parents reported that she had had difficulty hearing and speaking ever since they adopted her at 2 years of age. Her parents denied a history of acute otitis media, otorrhea, otalgia, vertigo, autophony, or tinnitus since her adoption. At 2.5 years of age, a diagnosis of hearing loss was made, and she was given hearing aids. Her parents believed that she had been doing well with both receptive and expressive language since she had received the hearing aids. At examination, she had small bilateral preauricular skin tags and normal pinna. Her external auditory canals were of a normal caliber bilaterally, with no otorrhea or lesions. The tympanic membranes were translucent and mobile at pneumatic otoscopy. There was no evidence of a middle ear lesion, nor was there a Schwartz sign. She had no nystagmus or vertigo at pneumatic otoscopy. Audiometry was performed and revealed moderate to severe conductive hearing loss bilaterally, with a mixed component present at 2000 KHz. She had normal bilateral middle ear pressure at tympanometry. Thin-section computed tomography (CT) of the temporal bone was performed.

Congenital malformation of the oval window: experience of radiologic diagnosis and surgical technique.

The aim of this study was to introduce and discuss the method of preoperative radiological diagnosis to the congenital absence or atresia of the oval window (OW), and the method of surgical treatment. From July 2010 through August 2014, patients with normal external canal and tympanic membrane but conductive hearing loss underwent high resolution CT scan (HRCT). The multi-planar reformation (MPR), a post-processing protocol, was used. The patients with diagnosis of OW atresia and malformed stapes preoperatively underwent surgical treatment. The vestibular drilled-out and promontory drilled-out technique was used to reconstruct the ossicular chain. In the preoperative radiological diagnosis, six patients (ears) were noted to have congenital absence or atresia of the oval window with malformed facial nerve (class 4) and two patients (ears) were found to have footplate fixation (class 2). In the surgical treatment of eight ears, the malformed structure was identified and the ossicular chain reconstruction was made in six ears. The coronal HRCT CT imaging and the MPR post-processing technique can provide us practical and definite information for surgical treatment, especially in the discrimination of OW atresia and the fixed stapedal footplate. The promontory drill-out technique, fenestration in the bottom of the basal turn, provides us a new method in the hearing reconstruction when the area of OW was fully covered by malformed facial nerve. This technique was first reported in the literature.

Anatomic Landmarks for Localization of the Vertical Segment of Facial Nerve on Multislice CT Multiplanar Reconstruction Images.

The facial nerve decompression via mastoid is simple and easy to expose the vertical segment of the facial nerve (VFN). The objective of this study was to find out the relationship between the VFN and anatomic landmarks to facilitate prediction of the location of VFN during facial nerve decompression. The different landmarks were cochlear window (CW), oval window (OW), promontorium tympani (PT), and mastoid antrum (MA). Parameters of 140 patients (280 observations) with healthy middle ears were measured on high-resolution spiral multislice computed tomographic multiplanar reconstruction (MPR) images that were parallel to the base plane. The data gained were analyzed by statistical method and were also analyzed with respect to side and gender. The angle between orientation of VFN to the CW of the longest distance and horizontal axis was larger on the left side than that of the right (P < 0.05). Our results may provide more detailed information to predict the location of VFN during facial nerve decompression through mastoid.

Abnormal CT findings are risk factors for otitis media-related sensorineural hearing loss.

OBJECTIVES: Inflammatory processes in chronic otitis media (COM) can damage the inner ear, resulting in sensorineural hearing loss (SNHL). The purpose of this study was to evaluate risk factors by computed tomography (CT) findings for COM-related SNHL in patients with unilateral COM. DESIGN: Records from January 2009 to December 2012 of 231 patients with unilateral COM and a normal contralateral ear were retrospectively evaluated. Bone conduction thresholds were calculated for each ear at 0.5, 1, 2, and 4 kHz. If bone conduction threshold averaged across the four frequencies of the COM ear was 10 dB greater than that of the contralateral ear, the patient was classified under the SNHL group. Temporal bone CT images were analyzed to determine the presence or absence of soft tissue density in the attic (medial/lateral), antrum, oval window niche, and round window niche. Multivariate analysis of sex, age (< 50 years; ≥ 50 years), disease duration (< 20 years; ≥ 20 years), perforation size (small; moderate; large) and the presence of soft tissue density in the attic (medial/lateral), antrum, oval window niche, and round window niche was used to determine the factors related to COM-related SNHL. RESULTS: Of the 231 patients, there were 51 patients (22.1%) in the SNHL group and 180 patients (77.9%) in the non-SNHL group. Multivariate analyses showed that the presence of soft tissue density in the antrum (odds ratio [OR] 3.80; 95% confidence interval [CI] 1.74-8.32; p = 0.001), age ≥ 50 years and more (OR 3.32; 95% CI 1.62-6.81; p = 0.001), disease duration ≥ 20 years (OR 2.80; 95% CI 1.31-6.02; p = 0.008), and the presence of soft tissue density in the round window niche (OR 2.42; 95% CI 1.12-5.21; p = 0.024) were independently related to COM-related SNHL. CONCLUSIONS: COM-related SNHL was present in 22% of ears with COM. The presence of soft tissue density in the antrum, determined from temporal bone CT, increased the OR of SNHL to 3.8. Age, disease duration, and the presence of soft tissue density in the round window niche were also independent predicting factors for SNHL. These findings may be used as informative references for patients with COM.

The location of the mastoid portion of the facial nerve in patients with congenital aural atresia.

In order to investigate the location of the mastoid portion of the facial nerve in patients with congenital aural atresia and to assess its effect on the round window middle ear implant (MEI) transducer implantation approach, 70 patients with unilateral congenital aural atresia were examined by computer tomography (CT). The patients were divided into two groups based on their ages: 44 patients in Group A (2-12 years) and 26 patients in Group B (13-29 years). CT scans were reviewed for each patient. Based on the CT findings, the mastoid portion of the facial nerve's spatial configuration with respect to the oval and round windows was qualitatively recorded. Additionally, the exact location of the facial nerve was measured quantitatively. The results suggested that of the 70 deformed ears, 57 had facial nerves located at the round window, six at the oval window, and seven at the normal site. Of the 70 normal opposite ears, 63 had facial nerves located at the normal site, and the other seven had facial nerves located at the round window. Based on the quantitative measurements, the mastoid portion of the facial nerve was more anteriorly positioned in the deformed ears: 3.44-6.09 mm more anteriorly located in Group A and 4.35-7.41 mm more anteriorly located in Group B. In conclusion, in patients with congenital aural atresia, the dislocation of the facial nerve could have significant effects on the surgical approach to round window MEI transducer implantation.

Isolated Congenital Middle Ear Malformations: Comparison of Preoperative High-Resolution CT and Surgical Findings.

OBJECTIVES: To compare preoperative temporal bone high-resolution computed tomography (HRCT) readings to intraoperative findings during exploratory tympanotomy for suspected cases of isolated congenital middle ear malformations (CMEMs) and summarize the malformations that can and cannot be diagnosed with HRCT. METHODS: A retrospective study was conducted. All cases were confirmed as isolated CMEMs during surgery. Detailed clinical records were reviewed, with a focus on imaging and surgical findings. RESULTS: One hundred and thirty-two patients and 145 ears were reviewed. Ninety cases (62.1%) could be identified as isolated CMEMs and at least one as middle ear anomaly using preoperative HRCT. Fifty-five cases (37.9%) were reported to be completely normal and the patients underwent exploratory tympanotomy to determine the final diagnosis. Stapes fixation, either alone or associated with other ossicular chain anomalies, contributed to 53.1% of the cases. Most cases of aplasia or dysplasia of the ossicular chain, for example, aplasia/dysplasia of the long process of the incus, aplasia of the stapes' superstructure, and atresia of the oval window were easily identified in preoperative HRCT. However, fixation of the ossicular chain can be elusive in HRCT, and exploratory tympanotomy is needed for a definitive diagnosis. CONCLUSIONS: HRCT provides helpful preoperative clinical information in CMEM and may obviate the need for middle ear exploration in some cases. The negative findings (anomalies that are difficult to identify through preoperative HRCT) and the positive findings (anomalies that are relatively easy to identify through preoperative HRCT) were summarized.

Oval window perilymph fistula in child with recurrent meningitis and unilateral hearing loss.

A 2-year-old boy presented to Ears, Nose and Throat (ENT) surgeons with unilateral hearing loss. Following a prodrome of upper respiratory tract infection (URTI), he developed two episodes of pneumococcal meningitis in quick succession. This case demonstrates an unusual cause of perilymph fistula diagnosed on imaging and confirmed surgically. He had failed the Newborn Hearing Screening Programme and was therefore referred to audiology, who confirmed profound sensorineural hearing loss in the right ear. MRI showed incomplete partitioning (type 1) of the right cochlea, suggesting cerebrospinal fluid (CSF) leak from the region of the stapes. Exploratory tympanotomy confirmed this, and proceeded to CSF leak repair, obliteration of the Eustachian tube, subtotal petrosectomy, abdominal fat grafting and blind sac closure. Although middle ear effusions are common; particularly in children with recent URTI, the possibility of otogenic CSF leak needs to be considered, especially in cases of recurrent meningitis.

CT Imaging Categorization and Biomarker Study of Anomalous Tympanic Segment of the Facial Nerves in Patients With Hearing Loss in the Absence of Microtia.

The purpose of this study is to categorize anomalous tympanic facial nerve (FN) on high-resolution computed tomography (HRCT) and to determinate the significance of associated temporal bone anomalies and congenital syndromes without microtia in patients with hearing loss. A retrospective analysis of HRCT findings in 30 temporal bones in 18 patients with anomalous FN was performed. Abnormalities of the tympanic FN were categorized as follows: category 1: FN medially positioned, but above the oval window; category 2: FN in the oval window niche; and category 3: FN below the oval window. Potential associated findings that were assessed included stapes abnormalities, oval window atresia, and inner ear anomalies, as well as the presence of a known congenital syndrome with hearing loss. The most common type of anomalous tympanic FN was category 1 (67%, n = 20), following by group 2 (20%, n = 6) and group 3 (13%, n = 4). Stapes anomalies were detected in 77% of temporal bones (n = 23), oval window atresia was detected in 43% of temporal bones (n = 13), and inner ear anomalies were detected in 70% of temporal bones (n = 21). Anomalous tympanic facial nerves in temporal bone with conductive hearing loss were often (60%) not associated with oval window atresia. The combination of aberrant tympanic FN and inner ear anomalies was significantly (P = .038) associated with a known congenital syndrome (6 patients), including CHARGE syndrome, oculo-auriculo-vertebral spectrum, Pierre-Robin sequences, and Down syndrome. Therefore, an anomalous tympanic FN in conjunction with inner ear anomalies appears to be a biomarker for certain congenital syndromes with hearing loss in the absence of microtia.

MR Imaging in Menière Disease: Is the Contact between the Vestibular Endolymphatic Space and the Oval Window a Reliable Biomarker?

BACKGROUND AND PURPOSE: No reliable MR imaging marker for the diagnosis of Menière disease has been reported. Our aim was to investigate whether the obliteration of the inferior portion of the vestibule and the contact with the stapes footplate by the vestibular endolymphatic space are reliable MR imaging markers in the diagnosis of Menière disease. MATERIALS AND METHODS: We retrospectively enrolled 49 patients, 24 affected by unilateral sudden hearing loss and 25 affected by definite Menière disease, who had undergone a 4-hour delayed 3D-FLAIR sequence. Two readers analyzed the MR images investigating whether the vestibular endolymphatic space bulged in the third inferior portion of the vestibule contacting the stapes footplate. This sign was defined as the vestibular endolymphatic space contacting the oval window. RESULTS: We analyzed 98 ears: 27 affected by Menière disease, 24 affected by sudden sensorineural hearing loss, and 47 that were healthy. The vestibular endolymphatic space contacting the oval window showed an almost perfect interobserver agreement (Cohen κ = 0.87; 95% CI, 0.69-1). The vestibular endolymphatic space contacting oval window showed the following: sensitivity = 81%, specificity = 96%, positive predictive value = 88%, and negative predictive value = 93% in differentiating Menière disease ears from other ears. The vestibular endolymphatic space contacting the oval window showed the following: sensitivity = 81%, specificity = 96%, positive predictive value = 96%, negative predictive value = 82% in differentiating Menière disease ears from sudden sensorineural hearing loss ears. CONCLUSIONS: The vestibular endolymphatic space contacting the oval window has high specificity and positive predictive value in differentiating Menière disease ears from other ears, thus resulting in a valid tool for ruling in Menière disease in patients with mimicking symptoms.

Imaging Criteria to Predict Surgical Difficulties During Stapes Surgery.

BACKGROUND AND PURPOSE: Stapes surgery for otosclerosis can be challenging if access to the oval window niche is restricted. The aim of this study was to determine the accuracy of the computed tomographic (CT) scan in the evaluation of anatomical distances, and to analyze its reliability in predicting surgical technical difficulties. MATERIAL AND METHODS: A total of 96 patients (101 ears) were enrolled in a prospective study between 2012 and May 2015. During surgery, we evaluated the distance D1 between the stapes and the facial nerve, distance D2 between the promontory and the facial nerve after ablation of the superstructure, and the intraoperative discomfort of the surgeon. On preoperative CT scans, we measured the width and depth of the oval window niche, and the angle formed by two axes starting from the center-point of the footplate, the first tangential to the superior wall of the promontory, and the second tangential to the inferior wall of the fallopian canal. RESULTS: Intraoperative distances D1 and D2 were correlated with the width of the oval window and with the facial-promontory angle measured on imaging. CT scan measurements of the facial-promontory angle and width of the oval window were associated with the degree of discomfort of the surgeon. The cut-off threshold for intraoperative subjective discomfort was computed as 1.1 mm for the width of the oval window niche, with a sensibility of 71% and a specificity of 84%. CONCLUSION: Preoperative imaging analysis of the oval window width and the facialpromontory angle can predict operative difficulty in otosclerosis surgery.

Otosclerosis: comparison of complex-motion tomography and computed tomography.

A prospective computed tomographic and complex-motion tomographic evaluation was performed in 18 suspected or proven cases of otosclerosis. Although there was good agreement between both methods, there was no greater diagnostic accuracy with computed tomography. However, computed tomography demonstrated the changes better than complex-motion tomography.

Imaging and clinical evaluation of isolated atresia of the oval window.

BACKGROUND AND PURPOSE: Congenital causes of hearing loss in children commonly are encountered, and imaging aids in diagnosis as well as presurgical evaluation. Atresia of the oval window not associated with atresia of the external auditory canal (EAC) is a rare cause of congenital hearing loss in children. We present the clinical and imaging findings in children with isolated oval-window atresia. METHODS: Atresia of the oval window was defined as the absence of the structure with the presence of a bony plate superimposed between the vestibule and middle ear. The bony plate is within the expected region of the oval window. Using a computerized database, nine patients with isolated oval-window atresia were found. All had been evaluated with high-resolution computed tomography (HRCT) and all had medical records available for review, including audiogram results. Imaging studies were interpreted by the consensus of two pediatric neuroradiologists. RESULTS: Atresia of the oval window was documented in all cases using HRCT criteria. The most common anomalies associated with oval-window atresia were inferomedial malposition of the facial nerve (n = 8), malformed incus (n = 6), and displaced stapes (n = 2). Four patients had symmetric bilateral involvement. Hearing tests were not specific, because conductive, sensorineural, and mixed patterns were found. CONCLUSION: Anomalies of the oval window should be sought in all patients with congenital hearing loss. Associated findings, such as facial nerve aberrancy and ossicular anomalies, are important in both diagnosis and surgical planning.

Congenital absence of the oval window: radiologic diagnosis and associated anomalies.

BACKGROUND AND PURPOSE: In most children with conductive hearing loss, acquired otitis media and/or middle ear effusion are ultimately diagnosed. Congenital conductive hearing loss is a rare condition; absence of the oval window is an unusual pathogenesis for this type of hearing impairment and can be associated with an anomalous horizontal facial nerve canal. Our goal was to describe the imaging features of congenital absence of the oval window, to determine the frequency with which anomalous development of the horizontal facial nerve canal occurs, and to review the developmental error responsible for this malformation. METHODS: Nine temporal bones in seven patients (5 to 36 years old) were found to have an inadequately formed oval window on high-resolution CT scans; seven ears showed complete lack of oval window formation, and two showed partial absence of the oval window. Records were reviewed for clinical information, and images were examined for associated anomalies. RESULTS: Six of nine ears with abnormal oval window formation showed malposition of the horizontal facial nerve canal. In each of these, the canal was abnormally low, overlying the expected location of the oval window; three of the canals lacked a visible bony covering. Seven of the nine ears were found to have a dysplastic or absent stapes. CONCLUSION: Congenital absence of the oval window can be diagnosed on CT studies. In the present series, this anomaly was associated with a grossly aberrant horizontal facial nerve canal in six of nine involved ears. Familiarity with the developmental sequence of oval window formation fosters an understanding of these anomalies. Preoperative recognition is important clinically, as a low facial nerve will block surgical access to the oval window and its presence will alter patient management.

Imaging of the windows of the temporal bone.

Imaging of the window of the temporal bone has became an important tool in the analysis of hearing loss, vertigo, tinnitus in a context of trauma, malformation, otosclerosis, and chronic otitis media. A good knowledge of the anatomy and a good technical procedure are necessary for making an efficient diagnosis. The increased thickness of the footplate may be delineated in otosclerosis, chronic otitis media, malformation, when it is measured at 0.7 mm or more in horizontal computed tomography (CT) sections. The traumatic displacement of the stapes, particularly within the labyrinths, is easily diagnosed in horizontal CT section. Imaging of the round window is now very important for the detection of otosclerotic foci, congenital stenosis, and perilymphatic fistula with or without fracture. Magnetic resonance imaging (MRI) with the high-resolution T2 plays an important role in the detection of a small amount of fluid in the round window recess, confirming the traumatic perilymphatic fistula without fracture.

Imaging of otosclerosis.

Imaging studies play an important role in the diagnosis of otosclerosis and in the clinical management of this disease. CT scanning at present is the tool of choice for the assessment of the labyrinthine windows and cochlear capsules. MR imaging thus far has had limited applications in the examination of the cochlear capsules but has been more useful in the assessment of the cochlear lumen prior to cochlear implant in patients with profound bilateral hearing loss.

Cerebrospinal fluid otorrhea in a patient with congenital inner ear dysplasia.

A case of a 10-month-old boy with a cerebrospinal fluid (CSF) fistula in his right ear is reported. In the same ear, the patient also showed congenital inner ear dysplasia. The CSF fistula was obstructed surgically. Surgical exploration showed a fistula superior to the oval window and a normally shaped stapes. The stapes was removed and the fistula was closed by obliteration of the vestibulum with the temporal fascia and fat tissue. The location of the fistula was very rare; to our knowledge, this is the first reported case of CSF fistula superior to the oval window. The relationship between perilymphatic fistula and the microfissure revealed by temporal bone study is discussed.

[Oval window canal and CT-diagnosis of peripheral pareses of the facial nerve]. / Fallopiev kanal i KT-diagnostika perifericheskikh parezov litsevogo nerva.

Computed tomography (CT) has examined 200 patients (400 temporal bones) at the age of 0-74 with unaffected facial nerve and 28 patients with symptoms of peripheral paresis or paralysis of the facial nerve of different genesis. Polyposition CT of the temporal bone is an intravital noninvasive method of the Fallopius' canal visualization. The canal is visualized on the tomograms in 100% cases irrespective of the patients' age. The following causes of n. facialis paresis were revealed: neurinoma of the facial nerve, sarcoma of the temporal bone, destruction of the tympanic canal wall in chronic otitis media, fractures of the temporal bone, malformations of the Fallopius' canal in malformations of the temporal bone, stenosis of the canal in fibrous dysplasia. The above alterations of n. facialis canal determine further therapeutic policy.

Oval window niche height: quantitative evaluation with CT before stapes surgery for otosclerosis.

BACKGROUND AND PURPOSE: Stapes surgery for otosclerosis can be challenging when the oval window niche is narrow. We analyzed the reliability of CT to evaluate the height of the OWN and propose a quantitative criterion to distinguish normal and narrow OWNs. MATERIALS AND METHODS: Fifty-six patients were scheduled for primary stapes surgery and, with available preoperative CT scans, were prospectively enrolled in the study at a tertiary care hospital. OWN height was measured on coronal CT and qualitatively evaluated during surgery. CT findings and surgical observations were matched to determine the preoperative imaging criterion of a narrow OWN. RESULTS: OWN was found to be narrow during surgery in 8 of 56 patients (14%). On CT, mean OWN height measurement was 1.1 mm for the narrow group and 1.8 mm for the normal OWN surgical cases. The cutoff between normal and narrow OWN was computed at 1.3 mm by using discriminant analysis and at 1.4 mm with boxplot analysis. These CT cutoff values allowed a correct classification of "normal" and "narrow" OWN, compared with visual evaluation during surgery. CONCLUSIONS: Measurements of the OWN height provide an accurate and relevant evaluation of this region before otosclerosis surgery. A width below 1.4 mm should be considered at risk for technical difficulties during the stapes footplate approach.

A case of pneumolabyrinth induced by Eustachian tube air inflation.

OBJECTIVES: Here, we report a case of pneumolabyrinth induced by Eustachian tube air inflation (ETAI) with a catheter and present evidence that multiple air bubbles entered the perilymphatic space through a preexisting oval window fistula. SETTING: Tertiary referral center. PATIENT: Sixty-six-year-old woman. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Air bubbles in the perilymphatic space revealed by cone beam computed tomography (CT) volume rendering imaging. RESULTS: The patient was referred to us because of vertigo, unsteadiness, and right hearing loss after ETAI using a Eustachian tube catheter. On Day 2, an audiogram showed right total deafness, and the perilymphatic space could not be identified on T2-weighted magnetic resonance imaging. A high-resolution cone beam CT scan obtained on Day 3 showed multiple air bubbles in the labyrinth. The volume rendering images clearly revealed a larger air bubble in the vestibule inside the footplate of the stapes and small air bubbles in the horizontal semicircular canal, superior semicircular canal, and basal and second turns of the cochlea. This finding indicates that the air bubbles entered the perilymphatic space through an oval widow fistula caused by a sudden elevation in intratympanic air pressure. Two months later, the air bubbles had disappeared, and the patient's high tone hearing had improved slightly. CONCLUSION: ETAI can cause a pneumolabyrinth if the intratympanic pressure rises beyond a certain critical level. In this situation, volume rendering imaging of high-resolution cone beam CT can be used to quantify and identify the air bubbles present. The images taken in this study suggest that air bubbles entered the perilymphatic space through a perilymphatic fistula.