Temporal Bone Imaging

Fruauff, Kristen; Coffey, Kristen; Chazen, J. Levi; Phillips, C. Douglas

doi:10.1097/rmr.0000000000000044

Cited by 9 publications

(3 citation statements)

References 35 publications

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“…The CT scan is mainly used to identify structures of the temporal bone, especially the course of the facial nerve and the size of the mastoid 9 . Nonetheless there is ongoing research regarding the detection of these structures in MRI 37,38 ; thus, preoperative planning is possible by using only MRI. Furthermore, postoperative control of the electrode can be determined in MRI 39 …”

Section: Discussionmentioning

confidence: 99%

Cochlear Duct Length Measurements in Computed Tomography and Magnetic Resonance Imaging Using Newly Developed Techniques

Taeger¹,

Müller-Graff²,

Ilgen³

et al. 2021

OTO Open

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Objective Growing interest in measuring the cochlear duct length (CDL) has emerged, since it can influence the selection of cochlear implant electrodes. Currently the measurements are performed with ionized radiation imaging. Only a few studies have explored CDL measurements in magnetic resonance imaging (MRI). Therefore, the presented study aims to fill this gap by estimating CDL in MRI and comparing it with multislice computed tomography (CT). Study Design Retrospective data analyses of 42 cochleae. Setting Tertiary care medical center. Methods Diameter (A value) and width (B value) of the cochlea were measured in HOROS software. The CDL and the 2-turn length were determined by the elliptic circular approximation (ECA). In addition, the CDL, the 2-turn length, and the angular length were determined via HOROS software by the multiplanar reconstruction (MPR) method. Results CDL values were significantly shorter in MRI by MPR ( d = 1.38 mm, P < .001) but not by ECA. Similar 2-turn length measurements were significantly lower in MRI by MPR ( d = 1.67 mm) and ECA ( d = 1.19 mm, both P < .001). In contrast, angular length was significantly higher in MRI ( d = 26.79°, P < .001). When the values were set in relation to the frequencies of the cochlea, no clinically relevant differences were estimated (58 Hz at 28-mm CDL). Conclusion In the presented study, CDL was investigated in CT and MRI by using different approaches. Since no clinically relevant differences were found, diagnostics with radiation may be omitted prior to cochlear implantation; thus, a concept of radiation-free cochlear implantation could be established.

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Section: Discussionmentioning

confidence: 99%

Cochlear Duct Length Measurements in Computed Tomography and Magnetic Resonance Imaging Using Newly Developed Techniques

Taeger¹,

Müller-Graff²,

Ilgen³

et al. 2021

OTO Open

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“…An intralabyrinthine hemorrhage may also be solely depicted by unenhancend T1w MPR [ 33 ]. The 3D CISS is a standard part of a complete posterior fossa and internal auditory canal protocol, and is a mainstay for imaging of the cisternal cranial nerves at the cerebellopontine angle and internal auditory canal [ 34 ].…”

Section: Discussionmentioning

confidence: 99%

Significant Artifact Reduction at 1.5T and 3T MRI by the Use of a Cochlear Implant with Removable Magnet: An Experimental Human Cadaver Study

et al. 2015

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ObjectiveCochlear implants (CIs) are standard treatment for postlingually deafened individuals and prelingually deafened children. This human cadaver study evaluated diagnostic usefulness, image quality and artifacts in 1.5T and 3T magnetic resonance (MR) brain scans after CI with a removable magnet.MethodsThree criteria (diagnostic usefulness, image quality, artifacts) were assessed at 1.5T and 3T in five cadaver heads with CI. The brain magnetic resonance scans were performed with and without the magnet in situ. The criteria were analyzed by two blinded neuroradiologists, with focus on image distortion and limitation of the diagnostic value of the acquired MR images.ResultsMR images with the magnet in situ were all compromised by artifacts caused by the CI. After removal of the magnet, MR scans showed an unequivocal artifact reduction with significant improvement of the image quality and diagnostic usefulness, both at 1.5T and 3T. Visibility of the brain stem, cerebellopontine angle, and parieto-occipital lobe ipsilateral to the CI increased significantly after magnet removal.ConclusionsThe results indicate the possible advantages for 1.5T and 3T MR scanning of the brain in CI carriers with removable magnets. Our findings support use of CIs with removable magnets, especially in patients with chronic intracranial pathologies.

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“…Omitting radiation is of high bene t, especially for children 42 , since there is growing evidence from epidemiological studies that radiation exposure of the brain poses further substantial risks [43][44][45] . In this concept preoperative planning of the implantation, like measuring the CDL 46,47 , the examination of the course of facial nerve 48 and the size of the temporal bone 49 , will be performed in MRI imaging. For intra-and postoperative control the presented system, may be used in combination with electrocochleography 50…”

Section: Discussionmentioning

confidence: 99%

Continuous Facial Nerve Stimulation During Cochlear Implantation – An Electrophysiological Technique to Control the Intracochlear Electrode Contact Position

Herrmann

Müller-Graff

Kaulitz

et al. 2021

Preprint

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Purpose: This proof of concept describes the use of evoked electromyographic (EMG) activation of the facial nerve for intraoperative monitoring of the electrode insertion during cochlear implantation (CI).Methods: Intraoperative EMG measurements from the facial nerve were conducted in nine patients undergoing CI implantation. Electric pulses were emitted from contacts on the CI array during and immediately after electrode insertion. For control, the results of EMG measurements were compared to postoperative flat panel volume computed tomography scans with secondary reconstruction (fpVCTSECO).Results: During insertion, the EMG response evoked by the electrical stimulation from the CI was growing with the stimulating contact approaching the facial nerve and declined with increasing distance. After full insertion, contacts on the apical half of the CI array stimulated higher EMG responses compared with those on the basal half. Comparison with postoperative imaging demonstrated that electrode contacts stimulating high EMG responses had the shortest distances to the facial nerve. Conclusion: It could be demonstrated that electrically evoked EMG activation of the facial nerve can be used to monitor the progress during CI electrode insertion and to control the intracochlear electrode position after full insertion.

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Temporal Bone Imaging

Cited by 9 publications

References 35 publications

Cochlear Duct Length Measurements in Computed Tomography and Magnetic Resonance Imaging Using Newly Developed Techniques

Cochlear Duct Length Measurements in Computed Tomography and Magnetic Resonance Imaging Using Newly Developed Techniques

Significant Artifact Reduction at 1.5T and 3T MRI by the Use of a Cochlear Implant with Removable Magnet: An Experimental Human Cadaver Study

Continuous Facial Nerve Stimulation During Cochlear Implantation – An Electrophysiological Technique to Control the Intracochlear Electrode Contact Position

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