Volumetric accuracy of cone-beam computed tomography

Comparative Evaluation of Temporomandibular Joint Parameters in Unilateral and Bilateral Cleft Lip and Palate Patients Using Cone-Beam CT: Focus on Growing vs. Non-Growing Subjects

BACKGROUND

Morphological differences in the temporomandibular joint (TMJ) are crucial for the treatment of patients with cleft lip and palate (CLP). This study aims to evaluate and compare the TMJ parameters in patients with unilateral and bilateral CLP across growing and non-growing age groups using cone-beam computed tomography (CBCT).

METHODS

CBCT records from 57 patients (23 males and 34 females) aged 6-50 years with a diagnosed unilateral or bilateral CLP were analyzed. Patients were categorized into four groups: growing unilateral (UGCLP), growing bilateral (BGCLP), non-growing unilateral (UNGCLP), and non-growing bilateral (BNGCLP). Measurements of TMJ parameters, including the mandibular fossa, articular eminence inclination, joint spaces, and roof thickness of the glenoid fossa, were conducted using CBCT images.

RESULTS

Significant differences were observed in the anterior joint space (AJS) and the roof of the glenoid fossa (RGF) between growing and non-growing unilateral cleft patients. Additionally, significant discrepancies were found in the articular eminence angle when comparing the cleft and non-cleft sides within the unilateral growing group. No significant differences were observed in TMJ parameters between the right and left sides among bilateral cleft patients.

CONCLUSIONS

The study highlights distinct TMJ morphological differences between growing and non-growing patients with CLP, emphasizing the importance of age-specific considerations in the treatment planning and growth monitoring of these patients.

Optimization of orofacial cleft imaging protocols using device-specific low-dose cone-beam computed tomography

OBJECTIVE

The aim of this study was to present optimized device-specific low-dose cone-beam computed tomography (CBCT) protocols with sufficient image quality for pre-surgical diagnostics and three-dimensional (3D) modelling of cleft defects.

METHODS

Six paediatric skulls were acquired, and an artificial bony cleft was created. A high-resolution CBCT scan acted as a reference standard (Accuitomo 170, Morita, Kyoto, Japan) for comparing eight low-dose protocols of Newtom VGi-evo (QR Verona, Cefla, Verona, Italy), which included Eco and Regular protocols with different field of views (FOVs). Delineation of lamina dura, cementoenamel junction (CEJ), trabecular bone and bony bridge were assessed. A 3D model of the defect was also evaluated.

RESULT

The dose area product of low-dose protocols ranged from 31 to 254 mGy*cm2. Despite the dose difference of up to eight times between applied protocols, trabecular bone and CEJ exhibited appropriate image quality in all scans. However, Regular small FOV protocols (5 × 5 and 8 × 5 cm2), for both lamina dura and bony bridge, demonstrated a significant improvement in image quality compared to Eco FOV counterparts. Based on 3D defect analysis, no significant difference existed between low-dose protocols and the reference standard.

CONCLUSION

The findings highlight the possibility of achieving a considerable reduction (up to eight times) in the radiation dose using low-dose CBCT protocols while maintaining sufficient image quality for assessing anatomical structures and 3D modelling in cleft cases.

Evaluation of Third Molar Maturity Index by Cone Beam Computed Tomography in Legal Age Estimation: A Preliminary Study

ABSTRACT

This retrospective study aimed to evaluate the accuracy and applicability of the third molar maturity index (I 3M ) for discriminating Turkish minors from adults, and its relationship with chronological age using cone beam computed tomography (CBCT). A total of 122 CBCT scans of Turkish individuals (55 boys and 67 girls) aged 13 to 23 years were evaluated using the I 3M cutoff value. Chronological age gradually decreased as the I 3M value increased. The overall accuracy was 95.9%. The sensitivity and specificity of this test were 93.5% and 97.4%, respectively. Positive predictive value was 95.6%. The intraclass correlation coefficient values of the I 3M for the intraobserver and interobserver agreements were 0.998 and 0.996, respectively. This study showed relatively higher reproducibility of measurements on CBCT scans than on panoramic radiographs in the literature. Cone beam computed tomography may be advantageous and preferred over panoramic radiographs in distinguishing the legal age threshold of 18 years according to Cameriere's method when a more extensive investigation is needed to support the solution of challenging and uncertain cases in forensic medicine.

AI-based automatic segmentation of craniomaxillofacial anatomy from CBCT scans for automatic detection of pharyngeal airway evaluations in OSA patients

This study aims to generate and also validate an automatic detection algorithm for pharyngeal airway on CBCT data using an AI software (Diagnocat) which will procure a measurement method. The second aim is to validate the newly developed artificial intelligence system in comparison to commercially available software for 3D CBCT evaluation. A Convolutional Neural Network-based machine learning algorithm was used for the segmentation of the pharyngeal airways in OSA and non-OSA patients. Radiologists used semi-automatic software to manually determine the airway and their measurements were compared with the AI. OSA patients were classified as minimal, mild, moderate, and severe groups, and the mean airway volumes of the groups were compared. The narrowest points of the airway (mm), the field of the airway (mm²), and volume of the airway (cc) of both OSA and non-OSA patients were also compared. There was no statistically significant difference between the manual technique and Diagnocat measurements in all groups (p > 0.05). Inter-class correlation coefficients were 0.954 for manual and automatic segmentation, 0.956 for Diagnocat and automatic segmentation, 0.972 for Diagnocat and manual segmentation. Although there was no statistically significant difference in total airway volume measurements between the manual measurements, automatic measurements, and DC measurements in non-OSA and OSA patients, we evaluated the output images to understand why the mean value for the total airway was higher in DC measurement. It was seen that the DC algorithm also measures the epiglottis volume and the posterior nasal aperture volume due to the low soft-tissue contrast in CBCT images and that leads to higher values in airway volume measurement.

A study on the association between the inferior nasal turbinate volume and the maxillary sinus mucosal lining using cone beam tomography

Objectives

The volume of the inferior turbinates (IT) and the lining of the maxillary sinuses are important parameters when assessing sino-nasal diseases. However, no radiographic studies have investigated the correlation between these parameters. The present study was conducted to analyze the association between IT volumes and thickness of maxillary sinus mucosal lining.

Materials and methods

A retrospective evaluation of the cone-beam computed tomography (CBCT) scans of 100 adult subjects was carried out by two radiologists. The scans were assigned to two groups (Group 1 & 2) based on the radiographic evidence of maxillary sinus lining in the CBCT scans. Group 1 consisted of 50 CBCT scans of subjects with no evidence of maxillary sinus mucosal lining, whereas Group 2 consisted of 50 subjects with evidence of maxillary sinus mucosal lining. The scans in the Group 2 were further sub-classified into five categories, based on the thickness of the maxillary sinus mucosal lining. Vesalius 3D software was used to evaluate the total volume of inferior nasal turbinates by the two radiologists and a mean volume was obtained for each study subject.

Results

The intraclass correlation coefficient (ICC) between the volumetric estimations performed by the two radiologist was 0.87. Analysis of the results revealed that there was no significant gender-based difference (Group 1, P = 0.67 and Group 2, P = 0.95) in the total turbinate volume in either of the study groups. The total turbinate volume did not show any significant correlation (Group 1, r = 0.24 and Group 2, r = 0.12) with the age. There was a significant increase (P = 0.001) in the total turbinate volume of the subjects in Group 2 compared to Group 1. Regression analysis revealed that the thickness of sinus lining correlated significantly (P = 0.001) with the total turbinate volume.

Conclusion

An increase in the total turbinate volume has been associated with an increase in the thickness of the maxillary sinus mucosal lining. The data from this study will be useful for post-operative follow-up of inferior turbinates and maxillary sinus lining after the turbinate volume reduction procedures.

3D landmarks of Craniofacial Imaging and subsequent considerations on superimpositions in orthodontics-The Aarhus perspective

OBJECTIVE

(a) To evaluate intra- and inter-observer reliability in landmarks placement along the three planes of space on cone-beam computed tomography (CBCT) data sets; (b) To evaluate whether the reliability of each landmark differs in CBCT scans characterized by two different voxel dimension and quality.

SETTING AND SAMPLE POPULATION

A total of 84 scans were used in this study: 49 scans were taken with the NewTom 3G, and 35 scans were taken with the NewTom 5G. The scans were characterized by an isotropic voxel dimension of 0.36 and 0.30 mm for the NewTom 3G and the NewTom 5G, respectively.

METHODS

A total of 13 landmarks were placed according to the corresponding definitions in 3D, also presented in this study: Foramen Spinosum (R/L), Nasion, Sella, Gonion (R/L), Pogonion, Menton, A point, Anterior nasal spine, Posterior nasal spine, Basion, Cribriform Plate (CR). Intra- and inter-observer reliability and Intra-class correlation coefficients (ICC) ICC for landmarks identification were assessed. Five reference and registration planes based on the above-mentioned landmarks were also presented.

RESULTS

ICC both for the intra- and inter-observer measurements had a score larger than 0.9 in all directions, except in the sagittal direction for CR. Regarding intra- and inter-observer reliability, only N, S, and Ba scored well in all directions.

CONCLUSIONS

Most of the landmarks analysed displayed a high reliability along at least 2 directions. The choice of landmarks to define registration and superimposition planes must be carefully selected, as the reliability of these planes is inherited from the one of the landmarks defining them.