Talus-derived reference coordinate system for 3D calcaneal assessment: A novel approach to improve morphological measurements

In 3D-analysis of the calcaneus, a consistent coordinate system aligned with the original anatomical directions is crucial for pre- and postoperative analysis. This importance stems from the calcaneus's key role in weight-bearing and biomechanical alignment. However, defining a reliable coordinate system based solely on fractured or surgically reconstructed calcanei presents significant challenges. Given its anatomical prominence and consistent orientation, the talus offers a potential solution to this challenge. Our work explores the feasibility of talus-derived coordinate systems for 3D-modeling of the calcaneus across its various conditions. Four methods were tested on nonfractured, fractured and surgically reconstructed calcanei, utilizing Principal Component Analysis, anatomical landmarks, bounding box, and an atlas-based approach. The methods were compared with a self-defined calcaneus reference coordinate system. Additionally, the impact of deviation of the coordinate system on morphological measurements was investigated. Among methods for constructing nonfractured calcanei coordinate systems, the atlas-based method displayed the lowest Root Mean Square value in comparison with the reference coordinate system. For morphological measures like Böhler's Angle and the Critical angle of Gissane, the atlas talus-based system closely aligned with ground truth, yielding differences of 0.6° and 1.2°, respectively, compared to larger deviations seen in other talus-based coordinate systems. In conclusion, all tested methods were feasible for creating a talus derived coordinate system. A talus derived coordinate system showed potential, offering benefits for morphological measurements and clinical scenarios involving fractured and surgically reconstructed calcanei. Further research is recommended to assess the impact of these coordinate systems on surgical planning and outcomes.

Investigation of the Relationships between Coat Colour, Sex, and Morphological Characteristics in Donkeys Using Data Mining Algorithms

This study was carried out in order to determine the morphological characteristics, body coat colour distribution, and body dimensions of donkeys raised in Turkey, as well as to determine the relationships between these factors. For this reason, the predictive performance of various machine learning algorithms (i.e., CHAID, Random Forest, ALM, MARS, and Bagging MARS) were compared, utilising the biometric data of donkeys. In particular, mean measurements were taken from a total of 371 donkeys (252 male and 119 female) with descriptive statistical values as follows: height at withers, 100.7 cm; rump height, 103.1 cm; body length, 103.8 cm; chest circumference, 112.8 cm; chest depth, 45.7 cm; chest width, 29.1 cm; front shin circumference, 13.5 cm; head length, 55 cm; and ear length, 22 cm. The body colour distribution of the donkeys considered in this study was calculated as 39.35% grey, 19.95% white, 21.83% black, and 18.87% brown. Model fit statistics, including the coefficient of determination (R²), mean square error, root-mean-square error (RMSE), mean absolute percentage error (MAPE), and standard deviation ratio (SD ratio), were calculated to measure the predictive ability of the fitted models. The MARS algorithm was found to be the best model for defining the body length of donkeys, with the highest R² value (0.916) and the lowest RMSE, MAPE, and SD ratio values (2.173, 1.615, and 0.291, respectively). The experimental results indicate that the most suitable model is the MARS algorithm, which provides a good alternative to other data mining algorithms for predicting the body length of donkeys.

Root and canal morphology of the maxillary second premolars as indicated by cone beam computed tomography

The aim was to evaluate the morphology of maxillary second premolars. The root canal configurations were classified according to Vertucci and a new system by Ahmed et al. based on CBCT images. In addition, the number of roots and the level where they bifurcated were identified, and morphological measurements were performed based on anatomical landmarks. Single-rooted forms were most common. Bifurcation occurred most often in the middle part of the root. The most common canal configuration was type I according to Vertucci and code ¹ SP¹ according to the new classification. The measurements showing the results were as follows (mm): palatal cusp/buccal cusp/the lowest point of the occlusal surface to pulp chamber ceiling 6.18/6.54/4.77; the ceiling of the pulp chamber was found at the CEJ in 92.28% of the specimens. The maxillary second premolars tended to be single-rooted and with one root canal.

Fetal thymus in the middle and late trimesters: Morphometry and development using post-mortem 3.0T MRI

The present study aimed to investigate the anatomical microstructure, features and signals of the fetal thymus by 3.0T FS-T2 weighted turbo spin echo sequences, which could provide imaging evidence for the evaluation of early-stage development of fetal thymus. In addition, the T2-weighted three-dimensional (3D) sequences and the 3D processing may contribute to the establishment of reference ranges for the fetal thymus. A total of 64 specimens obtained from the fetuses of 16-39 weeks of gestational age (GA) were scanned by 3.0T MRI. Morphological changes and quantitative measurements of the fetal thymus were assessed, including the anteroposterior diameter, width, height, surface area and volume. The shape of fetal thymus varied and the majority were X-shaped, with a narrow top and wide bottom. Morphology measurements demonstrated gradual growth with increasing GA. There were high linear correlations between width, height, surface area and volume and GA. No significant differences were observed between the sexes. Post-mortem 3.0T MRI clearly demonstrated changes in external contours and internal structure with GA. The images and data obtained reflect normal development of the fetal thymus and enrich the imaging data of fetal morphometry.

Morphological measurements of anatomical landmarks in human maxillary first molar pulp chambers and evaluation of number of pulp canal orifices using spiral computed tomography: An in vitro study

Context:

Comprehensive understanding of the anatomic position of pulp canal orifices and the measurements of the molar pulp space may maintain the pulp health during conservative tooth preparation and minimize the possibility of mishaps during endodontic therapy.

Aims:

The idea of the present study was to analyze the morphological measurements of anatomical landmarks in human maxillary first molar pulp chambers and evaluation of number of pulp canal orifices using three-dimensional spiral computed tomography (SCT).

Subjects and Methods:

One hundred and thirty extracted intact human adult maxillary first molars were chosen from the North Indian population and were analyzed using SCT in axial and coronal sections.

Statistical Analysis Used:

Standard deviation, mean, and coefficient of variance were calculated. Interobserver reliability was evaluated using kappa value to avoid any bias.

Results:

The results from our study showed that 69.23% of the sample teeth had four canal orifices, the mesial and distal pulp horns were present at an average distance of 0.80 ± 0.36 mm and 0.41 ± 0.34 mm, respectively, above the cementoenamel junction (CEJ), and the mean distance from the central groove of central fossa to furcation and the central groove of central fossa to the pulp chamber's roof was 8.37 ± 0.33 mm and 3.87 ± 0.29 mm, respectively. The average distance of the pulp chamber's floor from the furcation was found to be 2.47 ± 0.11 mm. The highest degree of variance was observed in case of relation of CEJ to pulp horns, i.e., 44.85% and 82.60%.

Conclusions:

The dimensions observed in this study and its resemblance to the various studies reported in literature shift the fundamental anatomic approach to a more systemic quantifiable approach to the endodontic maxillary first molar access preparation.