UNASSIGNED: The utility of brain magnetic resonance imaging (MRI) for predicting dementia is debated. We evaluated the added value of repeated brain MRI, including atrophy and cerebral small vessel disease markers, for dementia prediction. We conducted a landmark competing risk analysis in 1716 participants of the French population-based Three-City Study to predict the 5-year risk of dementia using repeated measures of 41 predictors till year 4 of follow-up. Brain MRI markers improved significantly the individual prediction of dementia after accounting for demographics, health measures, and repeated measures of cognition and functional dependency (area under the ROC curve [95% CI] improved from 0.80 [0.79 to 0.82] to 0.83 [0.81 to 0.84]). Nonetheless, accounting for the change over time through repeated MRIs had little impact on predictive abilities. These results highlight the importance of multimodal analysis to evaluate the added predictive abilities of repeated brain MRI for dementia and offer new insights into the predictive performances of various MRI markers.
UNASSIGNED: We evaluated whether repeated brain volumes and cSVD markers improve dementia prediction.The 5-year prediction of dementia is slightly improved when considering brain MRI markers.Measures of hippocampus volume are the main MRI predictors of dementia.Adjusted on cognition, repeated MRI has poor added value over single MRI for dementia prediction.We utilized a longitudinal analysis that considers error-and-missing-prone predictors, and competing death.

The possibility of quick and cheap recognition of a fish species from a single dermal scale would be interesting in a wide range of contexts. The methods of geometric morphometry appear to be quite promising, although wide studies comparing different approaches are lacking. We aimed to apply two methods of geometric morphometry, landmark-based and outline-based, on a dataset of scales from five different teleost species: Danio rerio, Dicentrarchus labrax, Mullus surmuletus, Sardina pilchardus, and Sparus aurata. For the landmark-based method the R library \"geomorph\" was used. Some issues about landmark selection and positioning were addressed and, for the first time on fish scales, an approach with both landmarks and semilandmarks was set up. For the outline-based method the R library \"Momocs\" was used. Despite the relatively low number of scales analyzed (from 11 to 81 for each species), both methods achieved quite good clustering of all the species. In particular, the landmark-based method used here gave generally higher R2 values in testing species clustering than the outline-based method, but it failed to distinguish between a few couples of species; on the other hand, the outline-based method seemed to catch the differences among all the couples except one. Larger datasets have the potential to achieve better results with outline-based geometric morphometry. This latter method, being free from the problem of recognizing and positioning landmarks, is also the most suitable for being automatized in future applications.

The efficient use of various spatial cues within a setting is crucial for successful navigation. Two fundamental forms of spatial navigation, landmark-based and self-motion-based, engage distinct cognitive mechanisms. The question of whether these modes invoke shared or separate spatial representations in the brain remains unresolved. While nonhuman animal studies have yielded inconsistent results, human investigation is limited. In our previous work (Chen et al., 2019), we introduced a novel spatial navigation paradigm utilizing ultra-high field fMRI to explore neural coding of positional information. We found that different entorhinal subregions in the right hemisphere encode positional information for landmarks and self-motion cues. The present study tested the generalizability of our previous finding with a modified navigation paradigm. Although we did not replicate our previous finding in the entorhinal cortex, we identified adaptation-based allocentric positional codes for both cue types in the retrosplenial cortex (RSC), which were not confounded by the path to the spatial location. Crucially, the multi-voxel patterns of these spatial codes differed between the cue types, suggesting cue-specific positional coding. The parahippocampal cortex exhibited positional coding for self-motion cues, which was not dissociable from path length. Finally, the brain regions involved in successful navigation differed from our previous study, indicating overall distinct neural mechanisms recruited in our two studies. Taken together, the current findings demonstrate cue-specific allocentric positional coding in the human RSC in the same navigation task for the first time and that spatial representations in the brain are contingent on specific experimental conditions.

The multimodal and multidomain registration of medical images have gained increasing recognition in clinical practice as a powerful tool for fusing and leveraging useful information from different imaging techniques and in different medical fields such as cardiology and orthopedics. Image registration could be a challenging process, and it strongly depends on the correct tuning of registration parameters. In this paper, the robustness and accuracy of a landmarks-based approach have been presented for five cardiac multimodal image datasets. The study is based on 3D Slicer software and it is focused on the registration of a computed tomography (CT) and 3D ultrasound time-series of post-operative mitral valve repair. The accuracy of the method, as a function of the number of landmarks used, was performed by analysing root mean square error (RMSE) and fiducial registration error (FRE) metrics. The validation of the number of landmarks resulted in an optimal number of 10 landmarks. The mean RMSE and FRE values were 5.26 ± 3.17 and 2.98 ± 1.68 mm, respectively, showing comparable performances with respect to the literature. The developed registration process was also tested on a CT orthopaedic dataset to assess the possibility of reconstructing the damaged jaw portion for a pre-operative planning setting. Overall, the proposed work shows how 3D Slicer and registration by landmarks can provide a useful environment for multimodal/unimodal registration.

Sheep breeding has an important place in the world and in Turkey, as sheep are farm animals that provide most of their nutritional needs from pasture, have good adaptability and are low in cost. Akkaraman sheep and the Kangal Akkaraman sheep, which was considered its sub-variety until 2012, constitute half of the sheep population in Turkey. In this study, morphometric diversity between the skulls of Akkaraman and Kangal Akkaraman breed sheep was examined by geometric morphometric method. 2D images obtained from 3D models of 24 male sheep skulls from two different provinces were analyzed using 10 landmarks from dorsal and lateral views. The results from the dorsal view, the first three principal components (PC1, PC2 and PC3) accounted for a total of 64.13% of the morphological variation and the largest changes in are associated with external occipital protuberance, midline nasofrontal suture and rostral edge of the incisive fissure. From the lateral view, three first principal components explained the morphological variation 27.56%, 22.32% and 10.65% respectively. In the comparison of the skull morphology of Akkaraman and Kangal Akkaraman sheep from dorsal and lateral views, no allometric components were identified, as most of the described shape variations were not size-dependent. As a result of these analyses, more detailed information was obtained about the shape differences of the skull. Geometric morphometric analysis is successful in detecting differences in skull shape of different sheep breeds and can be successfully used for classification.

Egocentric representations of external items are essential for spatial navigation and memory. Here, we explored the neural mechanisms underlying egocentric processing in the retrosplenial cortex (RSC), a pivotal area for memory and navigation. Using one-photon and two-photon calcium imaging, we identified egocentric tuning for environment boundaries in dendrites, spines, and somas of RSC neurons (egocentric boundary cells) in the open-field task. Dendrites with egocentric tuning tended to have similarly tuned spines. We further identified egocentric neurons representing landmarks in a virtual navigation task or remembered cue location in a goal-oriented task, respectively. These neurons formed an independent population with egocentric boundary cells, suggesting that dedicated neurons with microscopic clustering of functional inputs shaped egocentric boundary processing in RSC and that RSC adopted a labeled line code with distinct classes of egocentric neurons responsible for representing different items in specific behavioral contexts, which could lead to efficient and flexible computation.

Non-human animals are exceptionally good at using smell to find their way through the environment. However, the use of olfactory cues for human navigation is often underestimated. Although the sense of smell is well-known for its distinct connection to memory and emotion, memory effects in human navigation using olfactory landmarks have not been studied yet. Therefore, this article compares wayfinding and recognition performance for visual and olfactory landmarks learned by 52 participants in a virtual maze. Furthermore, it is one of the first empirical studies investigating differences in memory effects on human navigation by using two separate test situations 1 month apart. The experimental task was to find the way through a maze-like virtual environment with either olfactory or visual cues at the intersections that served as decision points. Our descriptive results show that performance was above chance level for both conditions (visual and olfactory landmarks). Wayfinding performance did not decrease 1 month later when using olfactory landmarks. In contrast, when using visual landmarks wayfinding performance decreased significantly, while visual landmarks overall lead to better recognition than olfactory landmarks at both times of testing. The results demonstrate the unique character of human odor memory and support the conclusion that olfactory cues may be used in human spatial orientation. Furthermore, the present study expands the research field of human wayfinding by providing a study that investigates memory for landmark knowledge and route decisions for the visual and olfactory modality. However, more studies are required to put this important research strand forward.

A reliable landmark and precise distances from the ligament attachments are needed for lateral ankle stabilization surgery. The distal fascicle of the anterior inferior tibiofibular ligament (AITFL) has been used to locate the anterior talofibular ligament (ATFL) or calcaneofibular ligament (CFL) centers on the fibula. However, there is no anatomic study to validate the distal fascicle of the AITFL as a landmark of lateral ankle ligament stabilization, and more importantly, the exact distances from the ATFL or CFL attachments to the distal fascicle of the AITFL are unknown.
Sixteen frozen cadaveric specimens (8 paired specimens) with no previous history of ankle injury were used in this study. Whether the distal fascicle of AITFL was present in each specimen was confirmed. Then, the distances from the most distal insertion of the AITFL\'s distal fascicle to the footprint centers of the ATFL and CFL on the fibula were measured. All measurements were performed by 2 observers, and the intraobserver and interobserver reliabilities were analyzed by intraclass correlation coefficients (ICCs).
The distal fascicle of the AITFL was found in all specimens (100%). The mean distance from the most distal insertion of the AITFL\'s distal fascicle to the footprint centers of the ATFL, CFL, and the intersection center of the 2 ligaments on the fibula was 6.0 to 7.1 mm, 11.5 to 13.2 mm, and 9.0 to 10.0 mm, respectively. Excellent interobserver and intraobserver agreement (all ICCs > 0.9, P < .01) was shown in the anatomic measurements of these distances.
In this cadaveric study, we found that the distal fascicle was a constant structure of the AITFL in the lateral ankle. The distances from the most distal insertion of the AITFL\'s distal fascicle to the ligamentous footprint centers were reliable and may be used to identify the origins of the ATFL and CFL for lateral ankle ligament reconstruction.
This anatomic study validates the AITFL\'s distal fascicle as a potential landmark and, more importantly, determines the range of distances from AITFL\'s distal fascicle to the attachment centers of lateral ankle ligaments by anatomic measurements. The data may be used to identify the ATFL and CFL for lateral ankle stabilization surgery and become particularly valuable for endoscopic or arthroscopic techniques.

OBJECTIVE: The aim of this study was compare the palpation technique and ultrasound-guidance for femoral artery catheterization in pediatric patients undergoing surgery for congenital heart disease.
METHODS: This prospective and randomized controlled study included American Society of Anesthesiologists III-IV 40 children who underwent congenital heart surgery. The patients were divided into two groups; ultrasound-guided catheterization group and palpation-guided catheterization group. Demographic and clinical characteristics of the patients, access time, success rate, number of attempts, first-attempt success, number of trials, and failed cannulations were recorded.
RESULTS: The diameter of the femoral artery was significantly shorter, access time and numbers of trials were significantly lower, and first-attempt success rate was significantly higher in the US group. The complication rate was significantly higher in the P group. The number of failed catheterization was higher in the P group. Total cost required for the procedure was significantly lower in the US group.
CONCLUSIONS: We found that ultrasound-guided arterial catheterization increases the success rate and the number of successful catheterizations, while reducing the overall procedure time, incidence of complications, and cost. Therefore, we believe that the use of ultrasound guidance in arterial catheterization in pediatric cardiac surgery would be a better choice.
OBJECTIVE: El objetivo de este estudio fue comparar la técnica de palpación y ecoguiado para el cateterismo de la arteria femoral en pacientes pediátricos operados de cardiopatías congénitas.
UNASSIGNED: Este estudio prospectivo, aleatorizado y controlado incluyó a 40 niños ASA III-IV que se sometieron a cirugía cardíaca congénita. Los pacientes se dividieron en 2 grupos; Grupo de cateterismo guiado por ecografía y grupo de cateterismo guiado por palpación.
RESULTS: El diámetro de la arteria femoral fue significativamente más corto, el tiempo de acceso y el número de intentos fueron significativamente menores y la tasa de éxito del primer intento fue significativamente mayor en grupo estadounidense. La tasa de complicaciones fue significativamente mayor en el grupo P. El número de cateterismos fallidos fue mayor en el grupo P. El costo total requerido para el procedimiento fue significativamente menor en el grupo de EE.
CONCLUSIONS: Encontramos que el cateterismo arterial guiado por ultrasonido aumenta la tasa de éxito y el número de cateterismos exitosos, al tiempo que reduce el tiempo total del procedimiento, la incidencia de complicaciones y el costo. Por tanto, creemos que el uso de guía ecográfica en cateterismo arterial en cirugía cardiaca pediátrica sería una mejor opción.

Background: Accurate pre-operative planning is essential for successful high tibial osteotomy (HTO). The lateral tibial spine is a commonly used anatomical landmark for weight-bearing line assessment. However, studies on the mediolateral (M-L) position of the lateral tibial spine on the tibial plateau and its variability are limited. Purpose: This study aimed to (1) analyze the M-L position of the lateral tibial spine on the tibial plateau and its variability, (2) investigate radiologic parameters that affect the position of the lateral tibial spine, and (3) determine whether the lateral tibial spine can be a useful anatomical landmark for weight-bearing line assessment during HTO. Materials and Methods: Radiological evaluation was performed on 200 participants (64% female, mean age 42.3 ± 13.2 years) who had standing anterior-posterior plain knee radiographs with a patellar facing forward orientation. The distances from the medial border of the tibial plateau to the lateral spine peak (dLSP) and lateral spine inflection point (dLSI) were measured using a picture archiving and communication system. The medial-lateral inter-spine distance (dISP) was also measured. All parameters were presented as percentages of the entire tibial plateau width. The relationships between the parameters were also investigated. Results: The mean value of dLSP was 56.9 ± 2.5 (52.4-64.5)%, which was 5% lower than the Fujisawa point (62%). The mean value of dLSI was 67.9 ± 2.2 (63.4-75.8)%, which was approximately 5% higher than the Fujisawa point. The values of the dLSP and dLSI were variable among patients, and the upper and lower 10% groups showed significantly higher and lower dLSP and dLSI, respectively, than the middle 10% group. The mean value of dISP was 16.5 ± 2.4%, and it was positively correlated with dLSP and dLSI. Conclusions: On average, the dLSP and dLSI were located -5% and +5% laterally from the conventional Fujisawa point, and they may be useful landmarks for correction amount adjustment during HTO. However, it should be noted that correction based on the lateral tibial spine can be affected by anatomical variations, especially in patients with small or large inter-spine distances.