Improved image quality of temporal bone CT with an ultrahigh-resolution CT scanner: clinical pilot studies

Ohara, Arisa; Machida, Haruhiko; Shiga, Hisae; Yamamura, Wataru; Yokoyama, Kenichi

doi:10.1007/s11604-020-00987-5

Cited by 13 publications

(7 citation statements)

References 22 publications

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“…Recently, ultra-high-spatial-resolution (UHSR) CT, with 0.25-mm detector elements and matrix size up to 2048, was introduced, showing better delineation of the fine anatomic temporal bone structures than conventional multidetector CT, which has detector elements of 0.5 mm or larger and a matrix size of 512 (17,18). The UHSR CT system has various focal spot sizes, the smallest being of nominal size 0.4 3 0.5 mm 2 (19), whereas the smallest focus size in standard multidetector CT is 0.8 3 0.9 mm 2 .…”

Section: Study Participantsmentioning

confidence: 99%

Ultra-High-Resolution CT to Detect Intracochlear New Bone Formation after Cochlear Implantation

Heutink¹,

Klabbers²,

Huinck³

et al. 2022

Radiology

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Background: Histopathologic studies reported that cochlear implantation, a well-established means to treat severe-to-profound sensorineural hearing loss, may induce inflammation, fibrosis, and new bone formation (NBF) with possible impact on loss of residual hearing and hearing outcome. Purpose:To assess NBF in vivo after cochlear implantation with ultra-high-spatial-resolution (UHSR) CT and its implication on long-term residual hearing outcome. Materials and Methods:In a secondary analysis of a prospective single-center cross-sectional study, conducted between December 2016 and January 2018, patients with at least 1 year of cochlear implantation experience underwent temporal bone UHSR CT and residual hearing assessment. Two observers evaluated the presence and location of NBF independently, and tetrachoric correlations were used to assess interobserver reliability. In addition, the scalar location of each electrode was assessed. After consensus agreement, participants were classified into two groups: those with NBF (n = 83) and those without NBF (n = 40). The association between NBF and clinical parameters, including electrode design, surgical approach, and long-term residual hearing loss, was tested using the x 2 and Student t tests.Results: A total of 123 participants (mean age 6 standard deviation, 63 years 6 13; 63 women) were enrolled. NBF was found in 83 of the 123 participants (68%) at 466 of 2706 electrode contacts (17%). Most NBFs (428 of 466, 92%) were found around the 10 most basal contacts, with an interobserver agreement of 86% (2297 of 2683 contacts). Associations between electrode types and surgical approaches were significant (58 of 79 participants with NBF and a precurved electrode vs 24 of 43 with NBF and a straight electrode, P = .04; 64 of 88 participants with NBF and a cochleostomy approach vs 18 of 34 with NBF and a round window approach, P = .03). NBF was least often seen in full scala tympani insertions, but there was no significant association between scalar position and NBF (P = .15). Long-term residual hearing loss was significantly larger in the group with NBF compared with the group without NBF (mean, 22.9 dB 6 14 vs 8.6 dB 6 18, respectively; P = .04). Conclusion:In vivo detection of new bone formation (NBF) after cochlear implantation is possible by using ultra-high-spatial-resolution CT. Most cochlear implant recipients develop NBF, predominately located at the base of the cochlea. NBF adversely affects long-term residual hearing preservation.

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Section: Study Participantsmentioning

confidence: 99%

Ultra-High-Resolution CT to Detect Intracochlear New Bone Formation after Cochlear Implantation

Heutink¹,

Klabbers²,

Huinck³

et al. 2022

Radiology

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“…Recently, several studies have evaluated the delineation ability of U-HRCT for normal structures of temporal bones, [12][13][14] and Hiraumi et al have presented the tympanic segment of CTN using U-HRCT. 14 However, their study was performed only in 11 healthy volunteers and did not evaluate the entire course of the CTN.…”

Section: Discussionmentioning

confidence: 99%

Improved visualization of the chorda tympani nerve using ultra‐high-resolution computed tomography

Fujiwara

Watanabe

Kashiwagi

et al. 2021

Acta Radiologica Open

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Background Recognition of the anatomical course of the chorda tympani nerve (CTN) is important for preventing iatrogenic injuries during middle-ear surgery. Purpose This study aims to compare visualization of the CTN using two computed tomography (CT) methods: conventional high-resolution CT (C-HRCT) and ultra‐high-resolution CT (U-HRCT). Materials and methods We performed a retrospective visual assessment of 59 CTNs in normal temporal bones of 54 consecutive patients who underwent both C-HRCT and U-HRCT. After dividing CTN into three anatomical segments (posterior canaliculus, tympanic segment, and anterior canaliculus), two neuroradiologists scored the visualizations on a four-point scale. Results On C-HRCT, the visual scores of the posterior canaliculus, tympanic segment, and anterior canaliculus were 3.5 ± 0.7, 1.6 ± 0.6, and 3.1 ± 0.7, respectively. The respective values were significantly higher in all segments on U-HRCT: 3.9 ± 0.2, 2.4 ± 0.6, 3.5 ± 0.6 ( p < 0.01). Although the difference in scores between methods was greatest for the tympanic segment, the visual score on U-HRCT was lower for the tympanic segment than for the anterior and posterior segments ( p < 0.01). Conclusion Ultra‐high-resolution CT provides superior visualization of the CTN, especially the tympanic segment.

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“…Recently, one of the first UHR-CTs with advanced detector elements (element size, 0.25 mm at isocenter, superfine detector grids) and a small focal spot size (smallest size 0.4 × 0.5 mm) was introduced and implemented into the clinical routine to further improve neurovascular imaging. First technical reports have demonstrated the capability of UHR-CT to improve image quality in temporal bone imaging [ 4 ], coronary artery imaging [ 5 , 6 ] and thoracic imaging [ 7 , 8 ]; however, the capability of UHR-CT in comparison to NR-CT in neurovascular imaging has not been investigated thoroughly. With this novel technology at hand we hypothesized that the UHR-CTA could provide superior image qualities compared to NR-CTA, hereby adding value to the visualization of smaller vessels and cerebrovascular lesions.…”

Section: Introductionmentioning

confidence: 99%

Improvement of Neurovascular Imaging Using Ultra-High-Resolution Computed Tomography Angiography

Ucar,

Frenzel,

Kronfeld

et al. 2023

Clin Neuroradiol

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Objective To evaluate diagnostic image quality of ultra-high-resolution computed tomography angiography (UHR-CTA) in neurovascular imaging as compared to normal resolution CT-angiography (NR-CTA). Material and Methods In this retrospective single-center study brain and neck CT-angiography was performed using an ultra-high-resolution computed tomography scanner (n = 82) or a normal resolution CT scanner (NR-CTA; n = 73). Ultra-high-resolution images were reconstructed with a 1024 × 1024 matrix and a slice thickness of 0.25 mm, whereas NR-CT images were reconstructed with a 512 × 512 matrix and a slice thickness of 0.5 mm. Three blinded neuroradiologists assessed overall image quality, artifacts, image noise, overall contrast and diagnostic confidence using a 4-point Likert scale. Furthermore, the visualization and delineation of supra-aortic arteries with an emphasis on the visualization of small intracerebral vessels was assessed using a cerebral vascular score, also utilizing a 4-point Likert scale. Quantitative analyses included signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), noise and the steepness of gray value transition. Radiation exposure was determined by comparison of computed tomography dose index (CTDIvol), dose length product (DLP) and mean effective dose. Interrater agreement was evaluated via determining Fleiss-Kappa. Results Ultra-high-resolution CT-angiography (UHR-CTA) yielded excellent image quality with superior quantitative (SNR: p < 0.001, CNR: p < 0.001, steepness of gray value transition: p < 0.001) and qualitative results (overall image quality: 4 (Inter quartile range (IQR) = 4–4); p < 0.001, diagnostic confidence: 4 (IQR = 4–4); p < 0.001) compared to NR-CT (overall image quality: 3 (IQR = 3–3), diagnostic confidence: 3 (IQR = 3–4)). Furthermore, UHR-CT enabled significantly superior delineation and visualization of all vascular segments, from proximal extracranial vessels to the smallest peripheral cerebral branches (e.g., UHR-CTA PICA: 4 (3–4) vs. NR-CTA PICA: 3 (2–3); UHR-CTA P4: 4 (IQR = 3–4) vs. NR-CTA P4: 2 (IQR = 2–3); UHR-CTA M4: 4 (IQR = 4–4) vs. NR-CTA M4: 3 (IQR = 2–3); UHR-CTA A4: 4 (IQR = 3–4) vs. NR-CTA A4: 2 (IQR = 2–3); all p < 0.001). Noteworthy, a reduced mean effective dose was observed when applying UHR-CT (NR-CTA: 1.8 ± 0.3 mSv; UHR-CTA: 1.5 ± 0.5 mSv; p < 0.001). Conclusion Ultra-high-resolution CT-angiography improves image quality in neurovascular imaging allowing the depiction and evaluation of small peripheral cerebral arteries. It may thus improve the detection of pathologies in small cerebrovascular lesions and the resulting diagnosis.

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Improved image quality of temporal bone CT with an ultrahigh-resolution CT scanner: clinical pilot studies

Cited by 13 publications

References 22 publications

Ultra-High-Resolution CT to Detect Intracochlear New Bone Formation after Cochlear Implantation

Ultra-High-Resolution CT to Detect Intracochlear New Bone Formation after Cochlear Implantation

Improved visualization of the chorda tympani nerve using ultra‐high-resolution computed tomography

Improvement of Neurovascular Imaging Using Ultra-High-Resolution Computed Tomography Angiography

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