Anatomy of the Transarcuate Approach to the Petrous Apex

2008 ◽  
Vol 139 (2_suppl) ◽  
pp. P98-P98
Author(s):  
Alice D Lee ◽  
Sanaz Hamidi ◽  
Hamid R Djalilian
Keyword(s):  
Computed Tomography ◽  
High Resolution ◽  
Semicircular Canal ◽  
Petrous Apex ◽  
Minimal Risk ◽  
High Resolution Computed Tomography ◽  
Superior Semicircular Canal ◽  
The Mean ◽  
Temporal Bones ◽  
Anterior Posterior

Problem The petrous apex is considered to be one of the most difficult areas of the temporal bone to approach surgically. We present data describing the dimensions of a transarcuate approach to the petrous apex, as measured on high resolution computed tomography. Methods Measurements of the mean dimensions and ranges through the crura of the superior semicircular canal were made. The measurements were obtained from high-resolution computed tomography images of 30 temporal bones in 19 consecutively presenting patients with a pneumatized posterior petrous apex cell tract on CT. Measurements were obtained with the use of the standard PACS (picture archiving and communication system) software. Results The mean anterior-posterior space in the superior semicircular canals without transcrural pneumatization was 4.96±0.39 mm. The mean superior- inferior dimension was 4.98±0.48 mm. The same measurements in canals with pneumatized intercrural tracts were 5.17±0.51 mm and 5.11±0.62 mm respectively. The mean anterior-posterior distance and superior-inferior distance of the intercrural air tracts themselves were 2.09±0.57 and 2.01±0.45mm. There was a statistically significant difference in the anterior-posterior size between the pneumatized and non-pneumatized canals but not in the superior-inferior distance. Conclusion Pneumatized bones demonstrate a slight increase in the subarcuate dimensions as compared to non-pneumatized bones. The transarcuate approach is a viable one for drainage and biopsy of the petrous apex. Significance Our study demonstrates that the transarcuate approach is anatomically possible for drainage of the petrous apex with minimal risk to the superior semicircular canal. This would be especially useful for the drainage of cholesterol granulomas of the petrous apex or biopsy in this area.

scholarly journals Radiographic Measurement of Cochlear in Sudanese Population using High Resolution Computed Tomography (HRCT)

2021 ◽  
Vol 29 (2) ◽  
Author(s):  
Lubna Bushara ◽  
Mohamed Yousef ◽  
Ikhlas Abdelaziz ◽  
Mogahid Zidan ◽  
Dalia Bilal ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Hearing Loss ◽  
High Resolution ◽  
Temporal Bone ◽  
Healthy Subjects ◽  
Cochlear Nerve ◽  
High Resolution Computed Tomography ◽  
Mean Width ◽  
The Mean ◽  
The Right

This study aimed to determine the measurements of the cochlea among healthy subjects and hearing deafness subjects using a High Resolution Computed Tomography (HRCT). A total of 230 temporal bone HRCT cases were retrospectively investigated in the period spanning from 2011 to 2015. Three 64-slice units were used to examine patients with clinical complaints of hearing loss conditions at three Radiology departments in Khartoum, Sudan. For the control group (A) healthy subjects, the mean width of the right and left cochlear were 5.61±0.40 mm and 5.56±0.58 mm, the height were 3.56±0.36 mm and 3.54±0.36 mm, the basal turn width were 1.87±0.19 mm and 1.88 ±0.18 mm, the width of the cochlear nerve canal were 2.02±1.23 and 1.93±0.20, cochlear nerve density was 279.41±159.02 and 306.84±336.9 HU respectively. However, for the experimental group (B), the mean width of the right and left cochlear width were 5.38±0.46 mm and 5.34±0.30 mm, the height were 3.53±0.25 mm and 3.49±0.28mm, the basal turn width were 1.76±0.13 mm, and 1.79±0.13 mm, the width of the cochlear nerve canal were 1.75±0.18mm and 1.73±0.18mm, and cochlear nerve density were 232.84±316.82 and 196.58±230.05 HU, respectively. The study found there was a significant difference in cochlea’s measurement between the two groups with a p-value < 0.05. This study had established baseline measurements for the cochlear for the healthy Sudanese population. Furthermore, it found that HRCT of the temporal bone was the best for investigation of the cochlear and could provide a guide for the clinicians to manage congenital hearing loss.

Reader accuracy and confidence in diagnosing diffuse lung disease on high-resolution computed tomography of the lungs: impact of sampling frequency

2008 ◽  
Vol 49 (8) ◽  
pp. 870-875 ◽  
Author(s):  
B. Sundaram ◽  
B. H. Gross ◽  
E. Oh ◽  
N. Müller ◽  
J. D. Myles ◽  
...  
Keyword(s):  
Computed Tomography ◽  
High Resolution ◽  
Lung Disease ◽  
Sampling Frequency ◽  
High Resolution Computed Tomography ◽  
Diffuse Lung Disease ◽  
First Choice ◽  
The Mean ◽  
The Impact ◽  
Diffuse Lung

Background: The accuracy of the number of high-resolution computed tomography (HRCT) images necessary to diagnose diffuse lung disease (DLD) is not well established. Purpose: To evaluate the impact of HRCT sampling frequency on reader confidence and accuracy for diagnosing DLD. Material and Methods: HRCT images of 100 consecutive patients with proven DLD were reviewed. They were: 48 usual interstitial pneumonia, 22 sarcoidosis, six hypersensitivity pneumonitis, five each of desquamative interstitial pneumonitis, eosinophilic granulomatosis, and lymphangioleiomyomatosis, and nine others. Inspiratory images at 1-cm increments throughout the lungs and three specified levels formed complete and limited examinations. In random order, three experts (readers 1, 2, and 3) ranked their top three diagnoses and rated confidence for their top diagnosis, independently and blinded to clinical information. Results: Using the complete versus limited examinations for correct first-choice diagnosis, accuracy for reader 1 (R1) was 81% versus 80%, respectively, for reader 2 (R2) 70% versus 70%, and for reader 3 (R3) 64% versus 59%. Reader accuracy within their top three choices for complete versus limited examinations was: R1 91% versus 91% of cases, respectively, R2 84% versus 83%, and R3 79% versus 72% of cases. No statistically significant differences were found between the diagnosis methods ( P=0.28 for first diagnosis and P=0.17 for top three choices). The confidence intervals for individual raters showed considerable overlap, and the point estimates are almost identical. The mean interreader agreement for complete versus limited HRCT for both top and top three diagnoses were the same (moderate and fair, respectively). The mean intrareader agreement between complete and limited HRCT for top and top three diagnoses were substantial and moderate, respectively. Conclusion: Overall reader accuracy and confidence in diagnosis did not significantly differ when fewer or more HRCT images were used.

scholarly journals An Anatomical Study of the Cochlea among Filipinos using High-Resolution Computed Tomography Scans

2011 ◽  
Vol 26 (1) ◽  
pp. 6-9 ◽  
Author(s):  
Adrian F. Fernando ◽  
Brian Joseph dG. De Jesus ◽  
Alejandro P. Opulencia ◽  
Gil M. Maglalang ◽  
Antoio H. Chua
Keyword(s):  
Computed Tomography ◽  
High Resolution ◽  
Average Length ◽  
Age Groups ◽  
Oval Window ◽  
University Hospital ◽  
High Resolution Computed Tomography ◽  
Basal Turn ◽  
The Mean ◽  
The Right

Objective: To describe the cochlear anatomy among Filipinos through high resolution computed tomography (HRCT) imaging.   Methods: Design: Retrospective Study Setting: Tertiary Private University Hospital Patients: Cochlear images retrospectively obtained from computed tomography (CT) scans of subjects who underwent cranial, facial, paranasal sinus and temporal bone computed tomography from October 2009 to July 2010 were reconstructed and analyzed.   Results: 388 cochlear images were obtained from the scans of 194 subjects (101 males and 93 females, aged 1 to 90 years old, mean = 52 years) and reconstructed for analysis. The mean coiled cochlear height measured 4.36 mm on the right (A.D.) and 4.34 mm on the left (A.S.). Measurement from the oval window to the distal end of the basal turn (equivalent to the horizontal dimension of the cochlea or the mean length of the basal turn) was 7.55 mm A.D. and 7.60 mm A.S. The vertical and horizontal dimensions of right and left cochleas were identical in all subjects (S.D. = 0.35). The right and left cochlear turns were identical in each subject, exhibiting 2 ½ turns in 92.3% of subjects and 2 ¾ turns in 7.7% of subjects.The cochlear dimensions were similar in all subjects, regardless of age. No cochlear ossification or malformation was noted on any CT image.   Conclusion: The 7.55 mm mean length of the cochlear basal turn among Filipinos in this study was 1.24 mm shorter than the average length of the basal turn of 8.81 mm reported elsewhere. Further studies of the cochlear dimensions in specific age groups and its correlation to audiometric status are recommended to determine other significant physiologic correlations.   Keywords: cochlea, cochlear turn, high-resolution computed tomography (HRCT), magnetic resonance imaging (MRI)

scholarly journals Head rotation evoked tinnitus due to superior semicircular canal dehiscence

2009 ◽  
Vol 124 (3) ◽  
pp. 333-335 ◽  
Author(s):  
E-C Nam ◽  
R Lewis ◽  
H H Nakajima ◽  
S N Merchant ◽  
R A Levine
Keyword(s):  
Computed Tomography ◽  
High Resolution ◽  
Semicircular Canal ◽  
Head Rotation ◽  
Bony Defect ◽  
Case Presentation ◽  
Superior Semicircular Canal Dehiscence ◽  
Superior Semicircular Canal ◽  
The Right ◽  
Canal Dehiscence

AbstractIntroduction:Superior semicircular canal dehiscence affects the auditory and vestibular systems due to a partial defect in the canal's bony wall. In most cases, sound- and pressure-induced vertigo are present, and are sometimes accompanied by pulse-synchronous tinnitus.Case presentation:We describe a 50-year-old man with superior semicircular canal dehiscence whose only complaints were head rotation induced tinnitus and autophony. Head rotation in the plane of the right semicircular canal with an angular velocity exceeding 600°/second repeatedly induced a ‘cricket’ sound in the patient's right ear. High resolution temporal bone computed tomography changes, and an elevated umbo velocity, supported the diagnosis of superior semicircular canal dehiscence.Conclusion:In addition to pulse-synchronous or continuous tinnitus, head rotation induced tinnitus can be the only presenting symptom of superior semicircular canal dehiscence without vestibular complaints. We suggest that, in our patient, the bony defect of the superior semicircular canal (‘third window’) might have enhanced the flow of inner ear fluid, possibly producing tinnitus.

High-Resolution Computed Tomography of the Inner Ear: Effect of Otosclerosis on Cochlear Aqueduct Dimensions

2019 ◽  
Vol 128 (8) ◽  
pp. 749-754 ◽  
Author(s):  
Helena Wichova ◽  
Sameer Alvi ◽  
Christine Boatright ◽  
Luke Ledbetter ◽  
Hinrich Staecker ◽  
...  
Keyword(s):  
Computed Tomography ◽  
High Resolution ◽  
Control Group ◽  
Control Cohort ◽  
Scala Tympani ◽  
High Resolution Computed Tomography ◽  
Cochlear Aqueduct ◽  
Length Width ◽  
The Mean ◽  
Bone Deposition

Objectives: The cochlear aqueduct is a bony duct connecting the scala tympani with the subarachnoid space. Given the pathophysiology of otosclerosis, including bone resorption and new bone deposition, we hypothesize that the cochlear aqueduct in otosclerotic ears is narrowed. Methods: A retrospective review of patients with otosclerosis who have undergone high-resolution computed tomography (HRCT) of the temporal bone was completed. The control cohort included 20 patients with the diagnosis of noise-induced hearing loss, without the diagnosis of otosclerosis. Uniform measurements of cochlear aqueduct dimensions were performed using the axial plane. Results: The otosclerosis cohort included 25 males and 52 females with mean age of 52.2 ± 17.6 years. The control group included 10 males and 10 females with mean age of 64.0 ± 18.5 years. The mean cochlear aqueduct length, width mid canal, aperture base, aperture widest diameter, and funnel diameter in millimeters were 12.19 ± 1.66, 0.68 ± 0.28, 4.21 ± 1.67, 3.23 ± 1.47, and 2.70 ± 1.05 in the ears with otosclerotic foci and 11.57 ± 1.66, 0.69 ± 0.29, 2.56 ± 1.59, 2.77 ± 1.67, and 2.58 ± 1.03 in control group, respectively. Statistical difference was seen in length of cochlear aqueduct, aperture base, and aperture widest diameters ( P = .017, <.001, .007). Conclusions: The length of the cochlear aqueduct and the funnel width are statistically longer in the otosclerotic population compared to control. The width of the cochlear aqueduct is not statistically different.

Evaluation of the mastoid air cell system by high resolution computed tomography: three-dimensional multiplanar volume rendering technique

2003 ◽  
Vol 117 (8) ◽  
pp. 595-598 ◽  
Author(s):  
Ahmet Koç ◽  
Gazanfer Ekinci ◽  
A. Mert Bilgili ◽  
Ihsan N. Akpinar ◽  
Hamdi Yakut ◽  
...  
Keyword(s):  
Computed Tomography ◽  
High Resolution ◽  
Temporal Bone ◽  
Volume Rendering ◽  
Three Dimensional ◽  
Cell System ◽  
Mastoid Cavity ◽  
High Resolution Computed Tomography ◽  
Mastoid Pneumatization ◽  
Temporal Bones

The mastoid air cell system is an important contributor to the pathophysiology of middle-ear inflammatory disease. The mastoid cavity is not only an air reservoir, but also an active space for gas exchange. Various methods of temporal bone imaging have been designed to investigate mastoid pneumatization. In this study, we examined 100 normal temporal bones for the evaluation of mastoid pneumatization. Mastoid air cell systems were measured by reconstructed axial and coronal high resolution computed tomography (HRCT) images. The reconstructions were made by a three-dimensional multiplanar volume rendering (3D MPVR) technique. The mean volume of the mastoid air cell pneumatization was 7.9 cm3 (4.0-14.0 cm3, SD = 2.3 cm3). The ears were allocated to the groups with respect to measured mastoid air cell pneumatization. Twenty-eight per cent of the ears have small pneumatization with an aircell system not exceeding 6 cm3. Fifty-two per cent had an air cell system between six and 10 cm3, and 20 per cent had an air cell system exceeding 10 cm3. With its excellent imaging quality and the ability to eliminate bone and soft tissue, HRCT is the best method for evaluating the mastoid air cell system. The 3D MPVR technique must be used tomeasure the temporal bone/mastoid pneumatization for the best results.

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