Research Presentation Session: Head and Neck

RPS 308 - Temporal bone and dental imaging

February 28, 11:30 - 12:30 CET

7 min
Radiologic prevalence and distribution of otic capsule dehiscence in patients with third window syndrome symptoms and a new classification
Yağmur Başak Polat, Istanbul / Turkey
Author Block: A. Yenigun, Y. B. Polat, E. Polat, S. Balsak, M. Basoz, S. Tugrul, O. Ozturan; Istanbul/TR
Purpose: The most well-known type of otic capsule dehiscence is Superior Semicircular Canal Dehiscence (SSCD). However, several other types of otic capsule dehiscence affect the semicircular canals, cochlea, and vestibule. Our research aimed to examine the frequency, distribution, and correlation between radiologic otic capsule dehiscence in patients exhibiting symptoms of third window syndrome. Additionally, we introduced a new classification system for semicircular canal dehiscence (SCD).
Methods or Background: In this retrospective study, we included cases who applied to the ENT department of our university hospital between January 2015 and September 2023 and underwent standard reformations and Pöschl plane CT scans due to symptoms suggestive of third window syndrome. A head and neck radiologist and a general radiologist jointly assessed each CT and decided on measurements and classifications.
Results or Findings: In the study, 219 patients (438 temporal bones) were examined. Semicircular canal dehiscences (SCD) were categorised into four types: type 0 (no SCD), type 1 (unilateral single canal dehiscence), type 2 (bilateral single canal dehiscence), and type 3 (unilateral multiple localisation dehiscence), and type 4 (bilateral multiple localisation dehiscence). SCD was observed in 69/219 (31.5%) patients; 150 were type 0 (68.5%), 29 type 1 (13.2%), 21 type 2 (9.6%), 15 type 3 (6.9%) and 4 were type 4 (1.8%). Cochlear-fascial dehiscence (CFD) and Vestibular aquaduct-jugular bulbus dehiscence (VA-JBD) were seen in 56/219 (25.6%) and 22/219 (10%) patients, respectively. Type 2 and Type 4 were significantly more frequent in cases with CFD than other types. VA-JBD was seen significantly more in Type 0 cases than in other types.
Conclusion: When we examine the otic capsule, we see that the possibility of CFD increases in bilateral SCD cases. The radiologist should evaluate the otic capsule as a whole. Particular attention should be paid to multiple channels, bilateral localisation as well as cochlear and vestibular dehiscences.
Limitations: No limitations were identified.
Funding for this study: No funding was received for this study.
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: This study received institutional review board approval and the reference number is E-54022451-050.05.04-125457.
7 min
Diagnostic value of cochlear nerve characteristics for occupational noise-induced hearing loss
Nan Wang, Tianjin / China
Author Block: N. Wang, L. Liu, L. Zhang, Y. Liu, L. Liu, J. Shi; Tianjin/CN
Purpose: The aim of this study was to explore the diagnostic value of cochlear nerve characteristics in the diagnosis of occupational noise-induced hearing loss (NIHL).
Methods or Background: This prospectively observational study included patients with NIHL, patients with noise exposure, and healthy volunteers at our hospital between January 2021 and September 2022. Multiplanar reconstruction of bilateral cochlear nerves was performed to extract the cochlear nerves characteristics, including the long diameter, short diameter, average diameter, length-to-diameter ratio, cross-sectional area, and perimeter of the cochlear nerves at three different planes, and the diagnostic value for NIHL were evaluated by area under the receiver operating characteristic curve (AUC).
Results or Findings: The NIHL (n=27, 24 males, aged 47.9±6.2 years), noise-exposed (n=41, 34 males, aged 46.9±6.7 years), and healthy control (n=27, 23 males, aged 48.0±6.1 years) groups were included. In the bottom plane, the short diameter (0.55±0.15 vs 0.75±0.16 mm), long diameter (0.83±0.18 vs 1.07±0.23 mm), average diameter (0.69±0.15 vs 0.91±0.18 mm), area (0.39±0.15 vs 0.72±0.21 mm2), and perimeter (2.33±0.48 vs 3.08±0.58 mm) of the NIHL group were significantly lower than those of the noise-exposed group (all P<0.05). The bottom plane area showed the best diagnostic value, with AUC of 0.921 (95% CI: 0.855-0.987).
Conclusion: Cochlear nerve characteristics might be helpful in the diagnosis of NIHL, and the bottom plane area showed the best diagnostic value.
Limitations: The sample of NIHL patients was relatively small; more patients need to be included in the future to evaluate the diagnostic efficacy of quantitative parameters of the cochlear nerve. Some patients' nerves were too slender, and so were smaller than the resolution of MR 3D-SPACE T2WI sequences. Some volume effects resulted in some layers of the cochlear nerves not being displayed, so those results could not be included in this study.
Funding for this study: MR 3D-SPACE T2WI sequences can measure the quantitative parameters of the cochlear nerve in NIHL patients in non-invasive and radiation-free conditions. These parameters can help with clinical differential diagnosis, distinguishing between NIHL patients and noise-exposed patients. The bottom plane had the highest diagnostic efficiency.
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: This study was approved by the clinical application project ethics committee of Tianjin occupational diseases precaution and therapeutic hospital.
7 min
Temporal bone fractures and related complications in patients with cranio-facial trauma: assessment with MDCT in the acute emergency setting
Marcella Pucci, Geneva / Switzerland
Author Block: M. Pucci, M. Becker, P. Senn, P. Scolozzi, P-A. A. Poletti, A. Platon; Geneva/CH
Purpose: The purpose of this study was to analyse the prevalence and complications of temporal bone fractures in adult and paediatric patients evaluated for cranio-facial trauma in the emergency setting.
Methods or Background: A retrospective blinded analysis was performed based on the CT scans of a series of 294 consecutive adult and paediatric patients with cranio-facial trauma investigated in the emergency setting. Findings between the two populations were compared. The preliminary reports done by the on-call residents were compared with the retrospective analysis by an experienced reader, which served as a reference standard.
Results or Findings: CT revealed 126 fractures in 116/294 (39.5%) of patients although fractures were suspected clinically only in 70/294 (23.8%), P<0.05. Fractures were longitudinal, transverse and complex in 69.5%, 10.3 % and 19.8 % of cases, respectively. Involvement of the tympanic cavity, external auditory canal, ossicular chain, facial nerve canal, and otic capsule was present in 54%, 72.2%, 8.7%, 6.3% and 4.8%, respectively. Injuries of the venous sinuses and carotid canal were seen in 18.3% and 17.5% of temporal bone fractures. Vascular injuries were more common in children than in adults (31.8% vs 15.7%, P<0.05). 79.5% of patients with temporal bone fractures had both brain injuries and fractures of the facial bones and cranial vault. Compared to the experienced reader, the sensitivity of the on-call residents was 103/116 (88.7%).
Conclusion: Temporal bone fractures and related complications in particular vascular injuries are common in patients with cranio-facial trauma and need to be thoroughly looked for, especially in children.
Limitations: This is a retrospective study. Possible underestimation of the true prevalence of temporal bone trauma due to the selection of patients based on the PACS records.
There was a lack of analysis of the initial and long-term clinical assessment.
Funding for this study: No funding was received for this study.
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: The institutional Ethics Committee approved this study.
7 min
Deep learning reconstruction algorithm with ultra-high resolution CT of the temporal bone: initial experience
Ulysse Puel, Nancy / France
Author Block: A. Beysang1, N. Villani1, F. Boubaker1, U. Puel1, A. Blum-Moyse1, P. A. Teixeira1, K. Haioun2, C. Parietti1, R. Gillet1; 1Nancy/FR, 2Otawara/JP
Purpose: The purpose of this study was to evaluate the image quality and clinical acceptance of a deep learning reconstruction (DLR) algorithm compared to traditional iterative reconstruction (IR) and simulated normal resolution (NR) reconstruction algorithms.
Methods or Background: CT acquisitions were performed using an ultra-high resolution CT device with a Mercury 4 phantom at three dose levels (25, 40, 51 mGy) and on 13 temporal bones at our routine dose level (about 500 mGy.cm). Images were reconstructed with two IR algorithms (model-based (MBIR) and hybrid (HIR)), one DLR algorithm with 0.25 mm slice thickness, and one simulated NR algorithm. In phantom acquisition, detectability was compared. Three radiologists performed quantitative (stapes footplate and superstructure thicknesses and lengths) and qualitative (posterior canaliculus, tympanic chorda tympani, stapes footplate and superstructure depiction) measurements in human temporal bones. Mean noise values in the external auditory canal air and lateral semi-circular canal bony island were compared.
Results or Findings: Using DLR, detectability was superior to other reconstruction algorithms at the three dose levels. All thicknesses were significantly superior using NR compared to DLR and IR algorithms, whereas lengths did not differ. DLR and MBIR were superior to NR and HIR for posterior canaliculus and stapes superstructure and footplate depiction. DLR was superior to all other algorithms for tympanic chorda tympani depiction. Compared to NR, there was twice as much noise in the air using HIR, but DLR and MBIR yielded significantly lower noise values. Bony noise values were lower using DLR and MBIR than with NR and HIR, which provided equivalent values.
Conclusion: DLR yielded a gain in objective measurement, closer to anatomical data, and in noise with the best clinical acceptance among the evaluated reconstruction algorithms.
Limitations: There was no surgical confirmation and the number of patients was small.
Funding for this study: No funding was received for this study.
Has your study been approved by an ethics committee? Not applicable
Ethics committee - additional information: This study was approved by the ethics committee of CHRU de Nancy.
7 min
Synthetic CT images of temporal, sinonasal and facial bones from MRI
Marlise Daniëlla Van der Veen, Amsterdam / Netherlands
Author Block: M. D. Van der Veen1, T. Van der Velden2, P. R. Seevinck2, J. Kuijer1, B. Schulten1, G. Adriaensen1, T. Goderie1, P. Merkus1, B. Jasperse1; 1Amsterdam/NL, 2Utrecht/NL
Purpose: Diagnostic evaluation and surgical planning of the head frequently require visualisation of both soft and bony tissues. Currently, this means a CT and MRI have to be obtained separately and then registered to combine the information from the two images.
The objective of this study is to train and evaluate a machine learning algorithm to generate synthetic bone CT images from MRI of the head.
Methods or Background: Paired 3T MRI (Philips, Siemens, GE) and CT scans of the head were used to train a vendor agnostic machine learning algorithm to generate synthetic CT images from the MRI data.
MRI scans of patients not included in algorithm training were used to create synthetic CT images, which could be compared to their corresponding true CT images.
A technical voxelwise comparison between synthetic CT and true CT was performed to quantify morphological and radiodensity accuracy.
To clinically evaluate the algorithm, six surgeons and two radiologists will evaluate the visibility of clinically relevant landmarks for three areas (temporal, sinonasal and facial bones) on both synthetic CT and true CT on a 4-point Likert scale.
Results or Findings: Voxelwise comparison showed a surface distance error of 0.38 ± 0.37 mm for the skull and a mean radiodensity error of 4 ± 44 HU, with a correlation coefficient of 0.79 ± 0.08.
In-depth clinical analysis of the images is currently ongoing and will be presented during the ECR 2024.
Conclusion: Generating synthetic CT images of the head from MRI is feasible, allowing inherently registered and efficient visualisation of soft and bony tissues using a single, radiation-free imaging modality.
Limitations: A limitation of the study is suboptimal blinding during evaluation of the scans, as synthetic CT and true CT can be visually distinguished by experienced physicians.
Funding for this study: Funding was provided by Amsterdam UMC, innovation impulse and by the research institute Amsterdam Public Health, within their programme Quality of Care.
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: The study was approved by the institutional review board of Amsterdam UMC, location VUMC (study number: 2022.0234). Written informed consent was obtained from all participants.
7 min
Dental imaging in clinical photon-counting CT at a quarter of DVT dose
Stefan Sawall, Heidelberg / Germany
Author Block: S. Sawall1, J. Maier1, S. Sen2, H. Gehrig1, T-S. Kim1, H-P. Schlemmer1, S. O. Schönberg3, M. Kachelrieß1, M. Rütters1; 1Heidelberg/DE, 2Kiel/DE, 3Mannheim/DE
Purpose: The main objective of this study was to investigate the image quality of a low-dose dental imaging acquisition protocol in the first clinical photon-counting computed tomography (PCCT) system in comparison to a normal-dose acquisition in a digital volume tomography (DVT) system.
Methods or Background: Clinical PCCT systems offer an increased spatial resolution compared to previous generations of clinical systems. Its spatial resolution is in the order of dental DVT systems. Resolution-matched acquisitions of ten porcine jaws were performed in a PCCT (Naeotom Alpha, Siemens Healthineers) and in a DVT (Orthophos XL, Dentsply Sirona). PCCT images were acquired with 90 kV at a dose of 1 mGy CTDI16 cm. DVT used 85 kV at 4 mGy. Image reconstruction was performed using the standard algorithms of each system to a voxel size of 160×160×200 μm. The dose-normalised contrast-to-noise ratio (CNRD) was measured between dentine and enamel as well as dentine and bone. Two experienced readers qualitatively evaluated overall diagnostic quality of images and quality of relevant anatomical structures such as root channels and dentine. Reproducibility was assessed using the intraclass correlation coefficient (ICC).
Results or Findings: CNRD is significantly higher in all PCCT acquisitions. In particular, CNRD is 37% higher for the contrast dentine-enamel and 31% higher for the dentine-bone contrast (p<0.05). Overall diagnostic image quality was higher for PCCT over DVT (p<0.02 and p<0.04 for readers 1 and 2). Quality scores for considered anatomical structures were higher in PCCT compared to DVT (all p<0.05). Inter- and intrareader reproducibility were acceptable (all ICC>0.75).
Conclusion: PCCT provides an increased image quality over DVT even at far lower dose levels.
Limitations: The study is limited to porcine ex-vivo samples since multiple measurements are required. The resulting intersection lengths might not accurately reflect the clinical case of a human patient.
Funding for this study: Not applicable for this study.
Has your study been approved by an ethics committee? Not applicable
Ethics committee - additional information: No approval was required for this study since the used porcine jaws are not considered an animal experiment.
7 min
Assessment of dental pulp by T2 mapping in vivo is influenced by age
Ksenija Cankar, Ljubljana / Slovenia
Author Block: K. Cankar, A. Golez, A. Tenyi, K. Romaric, T. Robida, J. Vidmar; Ljubljana/SI
Purpose: The cone beam computed tomography (CBCT) provide only information on hard dental tissues. This in vivo study tested whether standard 3T clinical MRI system can be used to quantify the dental pulp state using the T2 mapping method.
Methods or Background: Multi-echo-spin-echo (MESE) T2-weighted sequence in a single sagittal slice and with a field of view that covered the pulp chamber was employed. The teeth of the 15 subjects were divided in two groups according to their age. In the first group, children with the age between 11 and 15 were included (mean age 12.6±1.3 years) and in the second group were adults with the age between 24 and 48 (mean age 33.8±8.3 years). All T2 maps were calculated from the images of single-rooted premolar teeth. In the present study, only intact teeth without caries were included.
Results or Findings: In the group of adult’s teeth, there were statistically significantly higher T2 relaxation times in dental pulp (125.6±19.1 ms) compared to T2 relaxation times obtained in children’ teeth (111.9±11.2 ms) (p=0.022). In contrast, in the group of adult’s teeth there was lower variability of dental pulp tissue relaxation times (35.0±4.9 ms) compared to the pulp tissue in children’s teeth (44.6±8.4 ms) (p=0.0006).
Conclusion: An increase in the T2 relaxation times and a decrease in their variability in the adults could be attributed to lower cell to water ratio and increased homogeneity in the pulp tissue. The study confirmed that in vivo T2 mapping of dental pulp can be used to reliably quantify the dental pulp state. In healthy subjects, dental pulp assessment is strongly influenced by age.
Limitations: The teeth were not all from different subjects to maximize the number of teeth in the same field of view.
Funding for this study: This study was funded by the Ministry of Higher Education, Science and Technology, Slovenia: Grant No.P3-0019.
Has your study been approved by an ethics committee? Yes
Ethics committee - additional information: The study has been independently reviewed and approved by the Ethical Committee of the National Ministry of Health (Approval number 0120-659/2016/6).

This session will not be streamed, nor will it be available on-demand!