Publications (15) View all
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Article: Age-dependent differences of the anterior skull base.
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ABSTRACT: Imaging of the anterior skull base and paranasal sinuses is essential before surgery of the nose and paranasal sinuses. It is important to know individual anatomical variations to define a "dangerous ethmoid" to prevent complications such as considerable bleeding or injury to the brain. This study aimed to analyze the relevant parameters with special regard to age-dependent differences. This was a retrospective, single center study of 865 patients. Data from cone beam computed tomography (CBCT) of 116 patients less than 18 years of age and 749 adult patients were analyzed. Keros type, the course of the anterior ethmoid artery, the course of the uncinate process and the angle between the lateral lamella and the cribriform of the olfactory fossa were evaluated. Different frequencies of the course of the uncinate process between young and adult persons could be shown: onset at the lamina papyracea 67% vs. 64%; onset at the skull base, 22% vs. 26%; and onset at the middle turbinate, 11% vs. 10%. Differences in the course of the anterior ethmoid artery could be evaluated in the same way: course at the skull base, 49% vs. 44%; free course with a distance to the skull base of less than 3mm, 11% vs. 19%; and free course with a distance to the skull base more than 3mm, 40% vs. 37%. Significant differences could be found in the frequencies of the height of the olfactory fossa: Keros type I, 28% vs. 16%; Keros type II, 51% vs. 60%; and Keros type III, 21% vs. 24%. The angle between the lateral lamella and the cribriform plate showed significant differences dependent on the course of the anterior ethmoid artery (skull base=123° vs. distance<3mm=117° vs. distance>3mm=110°) and dependent on the height of the olfactory fossa (Keros type I=135° vs. Keros type II=117° vs. Keros type III=104°). Analysis of the angle as a factor of age and Keros type showed a significant difference in Keros type I (125° vs. 132°) and Keros type II (105° vs. 110°). Cone beam computed tomography (CBCT) of the anterior skull base allows the assessment of individual anatomical-radiological risk profiles and the identification of a "dangerous ethmoid". Significant age-dependent differences in the frequencies of anatomic landmarks and the angles of the ethmoid roof could be evaluated and led to significantly different risk profiles between children and adults.International journal of pediatric otorhinolaryngology 03/2012; 76(6):822-8. · 0.85 Impact Factor -
Article: Analysis of pneumatization and neurovascular structures of the sphenoid sinus using cone-beam tomography (CBT).
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ABSTRACT: The sphenoid sinus is a frequent target of paranasal sinus surgery. Because of the high risk of injuring the surrounding structures (e.g. internal carotid artery, optical nerve) a preoperative imaging is absolutely necessary. To analyze the possibilities of cone-beam computed tomography (CBCT), which is especially quite a new technique in ENT, in the evaluation of the sphenoid sinus, its surrounding structures, and the corresponding anatomical variations. This was a retrospective, single-centre study of 580 patients (1160 sides = cases). The Accu-I-Tomo-F17 was used. Pneumatization of sphenoid sinus, course of internal artery, course of optical nerve, and dehiscence of the bony canals were evaluated. In the case of pneumatization a type I (completely missing or minimal sphenoid sinus) was found in two patients (0.3%), type II (posterior wall of sphenoid sinus is in front of the anterior wall of the sella) in 38 patients (6.6%), type III (posterior wall is between anterior and posterior wall of sella) in 332 patients (57,2%), type IVa (posterior wall is behind the posterior wall of sella without air dorsal the sella) in 104 patients (17.9%), and type IVb (similar to type IVa but with air dorsal the sella) in 104 patients (17.9%). In 1025 cases (89.5%) a smooth course of the internal carotid artery was found whereas a free course could be detected in 120 cases (10.5%). Defects of the bony canal of the optical nerve were found in 16.7% and of the internal carotid artery in 2.7% of the cases. The optical nerve showed a free course through the sphenoid in 151 cases (13.7%) and a smooth course in 1007 cases (87.0%). CBCT could evaluate all relevant anatomic structures and answer the questions of different anatomical variants. A modified classification of the pneumatization of the sphenoid sinus could be described. Frequencies of anatomical variations are in accordance with the current literature of CT research.Acta Radiologica 03/2012; 53(2):214-9. · 1.37 Impact Factor -
Article: Prospective evaluation of reliability of cone beam computed tomography in detecting different position of vibroplasty middle ear implants.
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ABSTRACT: OBJECTIVES: This study had the following objectives: (i) To determine the accuracy of determination of Vibrant Soundbridge position in the spectrum of typically implanted sites in the middle ear. (ii) To assess inter-observer agreement between 3 observers with different levels of radiology experience. (iii) To determine the suitability of cone-beam computed tomography (CT) to be used as the baseline radiological assessment post implantation, confirm ferromagnetic transducer (FMT) position. DESIGN: Prospective research study. Using 4 fresh human cadaveric heads, different types of vibroplasty were performed. After each step, cone-beam CT was performed for each of the 4 cadaveric heads. SETTING: University hospital (ENT and Neuroradiology). PARTICIPANTS: Four fresh cadaveric heads of human donors were operated and analyzed by radiological imaging. MAIN OUTCOME MEASURES: There are different ways of coupling an FMT to the anatomical structures of the middle and inner ear. Possibilities of differentiation between these coupling variants should be presented. RESULTS: The individual reconstruction view was significantly different from a standardized view for each observer (observer 1: p = 0.003; observer 2: p = 0.001; observer 3: p = 0.002) for all coupling variants combined as well as for each individual coupling variant (overall correct diagnosis: 100% vs. 60%). Regarding the frequency of correct diagnosis, no significant differences were found between the 3 observers (p > 0.500) for each individual coupling variant as well as for all coupling variants combined. The worst rates of correct diagnosis were found in the standardized view for incus (42%), stapes (0%), and TORP (17%) vibroplasty. CONCLUSION: Cone-beam CT as a radiological control for Vibrant Soundbridge is safe and adequately sensitive and reliable and is therefore suitable for clinical investigation. The position of the FMT in the middle ear and the presence or absence of an additional coupler could be determined in this study. Therefore, cone-beam-CT is useful for the assessment of device failure when there has been gross displacement of the FMT (or smaller displacements in case of a baseline postoperative cone-beam CT). Regarding the quality of imaging, cone-beam CT produced accurate results with different observers with widely varying radiological experience. This article is protected by copyright. All rights reserved.Clinical otolaryngology: official journal of ENT-UK; official journal of Netherlands Society for Oto-Rhino-Laryngology & Cervico-Facial Surgery 05/2013; · 2.39 Impact Factor -
Article: [Imaging Quality and Dosage in ENT - What Do We Really Need?]
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ABSTRACT: Today, imaging of nose, paranasal sinuses and temporal bone by CT is standard in preoperative diagnostics. The need of reduction of applied dosage leads to the necessity of research in necessary imaging quality. Therefore this paper deals with new developed anatomical checklists and the analysis of imaging quality on anterior and lateral skull base.With 3 human complete heads over 400 examinations were performed on one cone beam CT device under varying x-ray-tube adjustments. 31 anatomic parameters were evaluated (Excellent, well, poor, not evaluable) for every data set. A summation score was built for every examination.As well for paranasal sinuses as for temporal bone a constant excellent imaging quality could be seen in high dosages. Certainly, in low dosages a reduction of imaging quality was detected. The optimal range (all parameters visualized well as average) could be evaluated for paranasal sinuses between 2,0 and 3,0 mGy and between 3,0 and 4,0 mGy for temporal bone. So, a reduction of 70-80% in comparison to highest adjustments of today is possible and realistic. In comparison to standard protocols, a reduction of about 50% can be reached.The possibility of dose reduction by discussion of the necessary imaging quality from clinical point of view could be shown.Laryngo-Rhino-Otologie 03/2013; · 0.97 Impact Factor -
Article: Potential of dosage reduction in cone-beam-computed tomography (CBCT) for radiological diagnostics of the paranasal sinuses.
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ABSTRACT: More than 10 years ago, cone-beam-computed tomography (CBCT) was introduced in ENT radiology. Until now, the focus of research was to evaluate clinical limits of this technique. The aim of this work is the evaluation of specific dosages and the identification of potential optimization in the performance of CBCT of the paranasal sinuses. Based on different tube parameters (tube current, tube voltage, and rotation angles), images of the nose and the paranasal sinuses were taken on a phantom head with the Accu-I-tomo F17 (Morita, Kyoto, Japan). The dosages applied to the lens and parotid gland were measured with OSL dosimetry. The imaging quality was evaluated by independent observers. All datasets were reviewed according to a checklist of surgically important anatomic structures. Even for lowest radiation exposure (4 mA, 76 kV, 180°, computed tomography dosage index (CTDI) = 1.8 mGy), the imaging quality was sufficient. Of course a significant reduction of the imaging quality could be seen, so a reliable mean was set for 4 mA, 84 kV, and 180° rotation angle (CTDI = 2.4 mGy). In this combination, a reduction of 92 % in lens-dose and of 77 % of dosage at the parotid gland was observed in comparison to the maximal possible adjustments (8 mA, 90 kV, 360°, CTDI = 10.9 mGy). There is potential for optimization in CBCT. Changing the rotation angle (180° instead of 360°) leads to a dose reduction of 50 %. Furthermore from clinical point of view in case of chronic rhinosinusitis a relevant reduction of dosage is possible. Therefore, it is necessary to intensify the interdisciplinary discussion about the disease specifics required quality of imaging.Archives of Oto-Rhino-Laryngology 09/2012; · 1.29 Impact Factor
