Analyse des Einsatzes der Digitalen Volumentomographie in der Routine der HNO-Bildgebung
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Philipps-Universität Marburg
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Abstract
Cone-beam Computed Tomography (CBCT) is an increasing radiological method in the diagnostic of frontal and lateral skull base. Because of the lower radiation dose in comparison to the CT, a higher spatial resolution and an easier application it becomes more and more important. The aim of this study was to show the importance of CBCT in daily use of the university hospital in Marburg. Thereby, the disparities in the adjustment between the different regions of examination, specific indications and different age groups should be clarified. For this study, every CBCT-image including questions of ENT from the years 2012 and 2013 was identified retrospectively. Technical parameters of the device, indications for imaging and the clinical follow-up of the patients were collected. This resulted in a group of 1862 patients with 1526 images of the frontal skull base and 335 images of the lateral skull base.
Related to the technical parameters there were significant differences between the regions concerning the average currency (mA), tube voltage (kV), FOV and rotation resulting in a lower CDTIw (mGy) for the images of the frontal skull base (2,90mGy vs. 5,92mGy). In this study there also could be shown that a change in protocol between the years 2012 to 2013 was conducted. There was a huge reduction of dosage in the lateral skull base due to this protocol change in rotation from 360° to 180° (6,97mGy vs. 4,17mGy). Because of its fine anatomic structure in the lateral skull base there is still a higher dosage and a commonly use of scout-imaging necessary. More repetitions of imaging can be recognized, too (3,6% vs. 2,4%). But with individualized adjustment of scout-imaging, rotation and FOV they can be reduced.
In both regions the frequency of the top 8-indications were determined.
In the region of the frontal skull base the most frequently used indication was the 'chronic sinusitis with insufficient nasal breathing' followed by the indications 'chronic sinusitis', 'fractures of the mid face', 'insufficient nasal breathing', 'acute sinusitis', 'nasal polyposis with insufficient nasal breathing', 'search of focus' and 'rhinorrhoea'. The frequent use of CBCT in area of rhinosinusitis can be explained by the german guidelines of rhinosinusitis from 2011, in which CBCT is already fixed and equalized to the CT. For other indications, this isn't carried out yet.
In the region of the lateral skull base the most frequently used indication was the 'control of the position of cochlear implants' followed by the indications 'cholesteatoma', 'status of the temporal bone with contralateral pathology', 'chronic otitis media mesotympanalis', 'disturbance of sound conduction', 'mastoiditis', 'tumor of the external ear canal' and 'otosclerosis'. Several studies in the past have shown the equality of CBCT and CT in the visualization of mid and inner ear. In the german guidelines of chronic inflammation of the mid and inner ear the CBCT is already advised.
In regard to underaged patients with their higher risk of radiation damage, there are differences in dosage compared with the adolescent patients (frontal skull base: 2,44mGy vs. 2,94mGy, lateral skull base: 4,76mGy, vs 6,02mGy). Variabilities in the CBCT-adjustment allowed an adaption to the smaller heads and need of a lower radiation dose. Therefore it became possible to reduce the dosage in the young collective. This could be emphasized in this study. Besides, the underaged collective shows a different grading of the indications. The acute trauma with a 'fracture of the mid face' is the most common indication in the frontal skull base and the 'cholesteatoma' in the lateral skull base.
Altogether, the CBCT is a relatively new radiological method, which is developing rapidly parallel to its clinical application. Therefore one can expect that in the future new protocols will be established. This may result in a further reduction of dosage and an increasing quality of the images. Also new fields like intraoperative application and hounsfield-adjusted tomographs are investigated. But because of the limitations in low-contrast resolution other imaging methods like MRI or modern technologies in CT have to be considered, too.
Besides, further research is needed to end the discussion of advantages of dosage between CBCT and CT and to define the value of CBCT in the single indications more precisely.
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Created: 2015Issued: 2015-03-24
Faculty
Medizin
Publisher
Philipps-Universität Marburg
Language
ger
Data types
DoctoralThesis
Keywords
ear-nose-throat medicineradiologyCBCTDigitale VolumentomographieCBCTskull baseindication
DFG-subjects
Hals-Nasen-Ohren-HeilkundeNaseDosisRadiologieDreidimensionale RekonstruktionVolumentomographieFelsenbeinSchädelbasisIndikation
DDC-Numbers
610
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Stutzki, Malene (106941400X): Analyse des Einsatzes der Digitalen Volumentomographie in der Routine der HNO-Bildgebung. : Philipps-Universität Marburg 2015-03-24. DOI: https://doi.org/10.17192/z2015.0172.
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This item has been published with the following license: In Copyright