Article Figures & Data
Figures
- Fig 1.
Flat panel CT of a right-sided cochlear implant. A, Collimated fluoroscopic acquisition for a 20-second FPCT of a right-sided CI. The skull above and below is excluded from the initial acquisition. B, Example of a coronal oblique image acquired after the default reconstruction. C, Secondary reconstruction by use of a manually generated voxel of interest is created to include only the electrode array. D, Higher-resolution coronal oblique image is generated after the secondary reconstruction.
- Fig 2.
Multiplanar reconstruction images of a right-sided cochlear implant. Multiplanar reconstruction axes are aligned parallel to the basal turn on the axial (A) and sagittal (B) planes to generate a coronal oblique (C) image of the CI. This image is rotated slightly to visualize the vestibule and superior semicircular canal. Arrow in (C) denotes the insertion point.
- Fig 3.
Secondary reconstructions comparing edge enhancement (A) and Hounsfield unit (HU) (B) kernel type show more distinct individual electrode contacts and osseous structures on the image generated by HU kernel type.
- Fig 4.
Coronal oblique secondary reconstructions of the same patient with cochlear implants. These images illustrate the variable image quality obtained with identical 3-mm section thickness, window width (3681), contrast (1246), and kernel type (HU). Note the blurring and poor visualization of the electrode contacts with the very smooth (A) setting. A sharp (D) parameter produces optimal images with well-defined osseous structures and individual electrode contacts. (A) Very smooth, (B) normal, (C) auto, (D) sharp.
- Fig 5.
High-resolution secondary reconstructions of all 14 patients and 18 cochlear implants (CIs). A–I, Nine right-sided CIs, including 1 patient (I) with an implanted medium array, are shown in the coronal oblique plane. J–R, Nine left-sided CIs are depicted, all of which are the standard length array. Images are arranged in order of descending angular insertion depth. All 216 individual electrode contacts are clearly visualized in all patients.
- Fig 6.
Method for calculating the angular insertion depth of the most apical electrode. The insertion point, as determined by the axial and sagittal images (not shown) is designated in the coronal oblique image. A circle whose outer circumference represents the trajectory of the 3 most apical electrodes is drawn. A reference line is drawn between the insertion point and the center of this circle. The most apical electrode is then identified and the angle θ is calculated between the electrode and the reference line. In this example, angular insertion depth is calculated by 360 ± θ.
- Fig 7.
Measured angular insertion depth of the most apical electrodes. Circles and triangles depict angular insertion depth for male and female patients with Med-El 31.5-mm standard array, respectively. Square refers to the single Med-El 24-mm medium array patient. Black filled shapes depict a right implanted ear; gray filled shapes depict a left implanted ear.
Tables
Subject Sex Age, y Etiology Implant Device Implant Side Fig 5 RW Insertion 1 F 59 Meniere Med-El Sonata, Standard Array Right B 2 F 48 Autoimmune Med-El Sonata, Standard Array Right H RW 3 M 62 Meniere Med-El Sonata, Standard Array Left R RW 4a M 51 Idiopathic Med-El Concert, Standard Array Right F RW Med-El Concert, Standard Array Left L 5 F 54 Hereditary Med-El Concert, Standard Array Left Q 6 F 21 Idiopathic Med-El Sonata, Standard Array Left P 7a M 59 Meniere Med-El Concert, Standard Array Right D Med-El Sonata, Standard Array Left M 8a M 62 Idiopathic Med-El Sonata, Standard Array Right C RW Med-El Sonata, Standard Array Left J 9 F 51 Idiopathic Med-El Concert, Standard Array Right G RW 10 M 61 Meniere Med-El Concert, Standard Array Left O 11a M 57 Idiopathic Med-El Sonata, Standard Array Right E Med-El Sonata, Standard Array Left K 12 M 49 Meningitis Med-El Concert, Standard Array Right A 13 M 61 Viral Med-El Sonata, Standard Array Left N 14 F 50 Idiopathic Med-El Concert, Medium Array Right I Note:—Demographic information for all 14 patients with cochlear implants include sex, age, etiology of hearing loss, type of CI, laterality, and corresponding image in Fig 5. Round window insertions are designated by RW.
↵a Subjects with bilateral CIs.
No. of Complete Turns Angular Insertion Depth <1 360 − θ >1, <1.5 360 + θ >1.5, <2 720 − θ >2 720 + θ Note:—Angular insertion depth calculations: The angular insertion depth for apical electrodes coursing <1 complete turn in relation to the zero degree line is calculated by 360 − θ; for >1 turn but <540° (1.5 turns), insertion depth equals 360 + θ; for >1.5 turns but <2 turns, insertion depth equals 720 − θ. For >2 turns, insertion depth equals 720 + θ.
Jump to section
Related Articles
Cited By...
- Cone-beam CT versus Multidetector CT in Postoperative Cochlear Implant Imaging: Evaluation of Image Quality and Radiation Dose
- Vestibular Implant Imaging
- Flat Panel Angiography in the Cross-Sectional Imaging of the Temporal Bone: Assessment of Image Quality and Radiation Dose Compared with a 64-Section Multisection CT Scanner