Application of 3D-printed pulmonary segment specimens in experimental teaching of sectional anatomy.

BACKGROUND: Lung cross-section is one of the emphases and challenges in sectional anatomy. Identification of the complex arrangement of intrapulmonary tubes such as bronchi, arteries, and veins in the lungs requires the spatial imagination of students. Three-dimensional (3D) printing has become increasingly used in anatomy education. This study aimed to analyze the effectiveness of 3D-printed specimens used for the experimental teaching of sectional anatomy. METHODS: A digital thoracic dataset was obtained and input into a 3D printer to print multicolor specimens of the pulmonary segment after software processing. As research subjects, 119 undergraduate students majoring in medical imaging from classes 5-8 in the second-year were chosen. In the lung cross-section experiment course, 59 students utilized 3D printed specimens in conjunction with traditional instruction as the study group, while 60 students received traditional teaching as the control group. Preclass and postclass tests, course grading, and questionnaire surveys were used to assess instructional efficacy. RESULTS: We obtained a set of pulmonary segment specimens for teaching. The students in the study group scored better in the postclass test than those in the control group (P < 0.05), and the students in the study group scored higher in satisfaction with the teaching content and spatial thinking for sectional anatomy than those in the control group (P < 0.05). The course grades and excellence rates in the study group exceeded those in the control group (P < 0.05). CONCLUSION: The application of high-precision multicolor 3D-printed specimens of lung segments in experimental teaching of sectional anatomy can improve teaching effectiveness and is worth adopting and promoting in sectional anatomy courses.

Three-Dimensional Modeling and Extended Reality Simulations of the Cross-Sectional Anatomy of the Cerebrum, Cerebellum, and Brainstem.

BACKGROUND: Understanding the anatomy of the human cerebrum, cerebellum, and brainstem and their 3-dimensional (3D) relationships is critical for neurosurgery. Although 3D photogrammetric models of cadaver brains and 2-dimensional images of postmortem brain slices are available, neurosurgeons lack free access to 3D models of cross-sectional anatomy of the cerebrum, cerebellum, and brainstem that can be simulated in both augmented reality (AR) and virtual reality (VR). OBJECTIVE: To create 3D models and AR/VR simulations from 2-dimensional images of cross-sectionally dissected cadaveric specimens of the cerebrum, cerebellum, and brainstem. METHODS: The Klingler method was used to prepare 3 cadaveric specimens for dissection in the axial, sagittal, and coronal planes. A series of 3D models and AR/VR simulations were then created using 360° photogrammetry. RESULTS: High-resolution 3D models of cross-sectional anatomy of the cerebrum, cerebellum, and brainstem were obtained and used in creating AR/VR simulations. Eleven axial, 9 sagittal, and 7 coronal 3D models were created. The sections were planned to show important deep anatomic structures. These models can be freely rotated, projected onto any surface, viewed from all angles, and examined at various magnifications. CONCLUSION: To our knowledge, this detailed study is the first to combine up-to-date technologies (photogrammetry, AR, and VR) for high-resolution 3D visualization of the cross-sectional anatomy of the entire human cerebrum, cerebellum, and brainstem. The resulting 3D images are freely available for use by medical professionals and students for better comprehension of the 3D relationship of the deep and superficial brain anatomy.

Contrast-enhanced computed tomography and cross-sectional anatomy of the trunk in the brownbanded bamboo shark (Chiloscyllium punctatum).

Computed tomography (CT) is used in veterinary medicine for the diagnosis of bones and soft tissue diseases in various species. In addition, CT has recently been used to diagnose aquatic animals, including Selachimorpha, which are difficult to diagnose out of water. However, because Selachimorpha do not have adipose tissue in the coelomic cavity, the coelomic organs cannot be fully identified using non-contrast CT (NCCT). The aim of this study is to present the anatomical features of the cadaver, NCCT, and contrast-enhanced CT (CECT) as well as the change in CT values of the coelomic organs and musculature of the brownbanded bamboo shark. NCCT scans were performed under anaesthesia in one male and one female shark. CECT was performed 30 min after iopamidol was administered intravenously. The sharks were euthanized, frozen at -20°C, and sliced in the same position in which they were scanned. Using electric band saw, 10-mm transversal sections were obtained. The anatomical structures of both males and females were identified by transversal sections, and CT images homologous to transversal sections were then selected. Sagittal and coronal CECT images were also obtained to facilitate understanding of the location and size of coelomic organs. Although bone structure and air in organs could be sufficiently discriminated on NCCT image, the coelomic organs were almost indistinguishable. On the other hand, CECT images obtained sufficient contrast to identify most coelomic organs in addition to bone and air. The results provide an atlas of a cross-sectional anatomy and CECT images, which is useful information for the medical diagnosis of coelomic organs in live Selachimorpha.

Mixed reality navigation training system for liver surgery based on a high-definition human cross-sectional anatomy data set.

OBJECTIVES: This study aims to use the three-dimensional (3D) mixed-reality model of liver, entailing complex intrahepatic systems and to deeply study the anatomical structures and to promote the training, diagnosis and treatment of liver diseases. METHODS: Vascular perfusion human specimens were used for thin-layer frozen milling to obtain liver cross-sections. The 104-megapixel-high-definition cross sectional data set was established and registered to achieve structure identification and manual segmentation. The digital model was reconstructed and data was used to print a 3D hepatic model. The model was combined with HoloLens mixed reality technology to reflect the complex relationships of intrahepatic systems. We simulated 3D patient specific anatomy for identification and preoperative planning, conducted a questionnaire survey, and evaluated the results. RESULTS: The 3D digital model and 1:1 transparent and colored model of liver established truly reflected intrahepatic vessels and their complex relationships. The reconstructed model imported into HoloLens could be accurately matched with the 3D model. Only 7.7% participants could identify accessory hepatic veins. The depth and spatial-relationship of intrahepatic structures were better understandable for 92%. The 100%, 84.6%, 69% and 84% believed the 3D models were useful in planning, safer surgical paths, reducing intraoperative complications and training of young surgeons respectively. CONCLUSIONS: A detailed 3D model can be reconstructed using the higher quality cross-sectional anatomical data set. When combined with 3D printing and HoloLens technology, a novel hybrid-reality navigation-training system for liver surgery is created. Mixed Reality training is a worthy alternative to provide 3D information to clinicians and its possible application in surgery. This conclusion was obtained based on a questionnaire and evaluation. Surgeons with extensive experience in surgical operations perceived in the questionnaire that this technology might be useful in liver surgery, would help in precise preoperative planning, accurate intraoperative identification, and reduction of hepatic injury.

Inclusion of cross-sectional and radiological images for better understanding of musculoskeletal anatomy and decreasing the risk of adverse events during dry needling in undergraduate physiotherapy students.

Since there is an increasing rate of physiotherapists using invasive procedures during the clinical practice, understanding the cross-sectional anatomy and radiological images is essential for ensuring patients' safety during these interventions. Therefore, the aim of this study was to analyze the students' opinion of including cross-sectional and radiological images to traditional methodologies, to evaluate whether these additional resources improve their ability to identify musculoskeletal structures in radiological images and their understanding of neurovascular and visceral structures related with specific muscles to be avoided during invasive procedures. First-year undergraduate physiotherapy students were enrolled in the study. A brief online survey asking about their opinion about the use of cross-sectional and radiological images as complementary resources was built. In addition, two open-answer tests (before and after the inclusion of these resources) were conducted to evaluate their ability to identify correctly musculoskeletal structures in magnetic resonance and ultrasound images and to evaluate their awareness of high-risk structures related with specific muscles. One-hundred-thirty-two students returned the online survey and one-hundred-forty-eight completed all the tests. In general, students opined cross-sectional images to be of utility for learning anatomy (81.8%) and radiological images (93.9%) and felt they benefited from cross-sectional and ultrasound images (78.0%). All tests showed significant improvements after the inclusion of these complementary resources (all, p < 0.001) except for trunk structures in MRI (p = 0.777). The implementation of anatomical cross-sectional and radiological images resulted in better understanding of radiological images and better cognition of possible risk during invasive procedures.

CT and cross-sectional anatomy of the paranasal sinuses in the Holstein cow.

The structure of paranasal sinuses in cattle is difficult to understand due to its complexity, age-related changes, and insufficient published data. In this prospective, anatomic study, we described the anatomy of the paranasal sinuses in the Holstein cow using computed tomography (CT) and cross-sectional anatomic slices. Twelve healthy adult Holstein cow heads were used for this study. The heads were scanned using CT, and frozen anatomical sections were taken. The locations, borders, and relationships of the paranasal sinuses were defined on the anatomical sections and CT images. The paranasal sinuses on each side of the head consisted of conchal (dorsal, middle, and ventral), maxillary, lacrimal, palatine, frontal, sphenoid sinuses, and ethmoidal cells. The frontal sinus pneumatized all bones surrounding the cranial cavity, except for the ethmoidal and body of basisphenoid bones. The sphenoid and ventral conchal sinuses were the most asymmetrical, and the middle conchal sinus was the simplest. The ventral conchal sinus was detected in eleven animals, one of which was unilateral. This sinus communicated with the middle nasal meatus (13/21) and ventral nasal meatus (8/21). Findings can be used as background for interpreting CT studies of cattle with clinical signs of sinonasal region diseases. Future cross-sectional radiological and reconstructive anatomical studies and investigation of the postnatal development of related structures in cattle are needed.

Abdominal ultrasound in amazonian manatee (Trichechus inunguis) (Natterer, 1883) / Ultrassonografia abdominal em peixe boi amazônico (Trichechus inunguis (Natterer, 1883)

Morphophysiological species researches are fundamental, and diagnostic imaging is an excellent technique, already used in wild animals, with great application, not invasive and provide real-time information of each body. Amazonian manatees are on the list of endangered animals classified in the vulnerable category and knowledge of the normal pattern of ultrasound anatomy of organs and tissues is important for the maintenance and well-being of captive specimens contributing to reintroduction actions. The objective of the study was to standardize the examination technique and describe the ultrasound findings of the liver, gallbladder, stomach, urinary bladder and the subcutaneous tissue of the abdominal region in Trichechus inunguis, in order to contribute with the anatomical and sonographic knowledge and assist in the diagnosis and prognosis diseases. The study used 18 animals to describe the normal sonographic anatomy in the abdominal cavity of the Amazonian manatee. During abdominal scan, it was possible to visualize the features of the liver, gallbladder, stomach, urinary bladder obtained satisfactory results in this study. Therefore, other structures were not primarily identified by the reduced time, lots of fat and gases in intestines of animals.

Pesquisas morfofisiológicas em espécies selvagens são fundamentais, e o diagnóstico por imagem é uma excelente técnica, já usada e com grande aplicação, não invasiva e que fornece informações em tempo real de cada órgão. Peixes-boi-amazônico encontram-se na lista de animais ameaçados de extinção classificados na categoria vulnerável e o conhecimento do padrão normal da anatomia ultrassonográfica de órgãos e tecidos é importante para a manutenção e bem-estar de espécimes em cativeiro contribuindo para ações de reintrodução. O objetivo deste estudo foi padronizar a técnica de exame e descrever os achados ultrassonográficos do fígado, vesícula biliar, estômago, vesícula urinária e o tecido subcutâneo da região abdominal em Trichechus inunguis, de modo a contribuir com o conhecimento anátomo-sonográfico e auxiliar no diagnóstico e prognóstico de doenças. O estudo utilizou 18 animais para descrever a anatomia ultrassonográfica normal na cavidade abdominal de peixe-boi amazônico. Durante a varredura abdominal foi possível visualizar as características dos órgãos obtendo resultados satisfatórios neste estudo, concluindo ser uma técnica eficiente para avaliação de determinados órgãos abdominais em peixe-boi amazônico. Entretanto, outras estruturas não foram identificadas principalmente pelo tempo reduzido, muita gordura e gases nos intestinos dos animais.

Determinants of whole-body maximal aerobic performance in young male and female athletes: The roles of lower extremity muscle size, strength and power.

This study sought to determine whether lower extremity muscle size, power and strength could be a determinant of whole-body maximal aerobic performance in athletes. 20 male and 19 female young athletes (18 ± 4 years) from various sporting disciplines participated in this study. All athletes performed a continuous ramp-incremental cycling to exhaustion for the determination of peak oxygen uptake ([Formula: see text]: the highest [Formula: see text] over a 15-s period) and maximal power output (MPO: power output corresponding to [Formula: see text]). Axial scanning of the right leg was performed with magnetic resonance imaging, and anatomical cross-sectional areas (CSAs) of quadriceps femoris (QF) and hamstring muscles at 50% of thigh length were measured. Moreover, bilateral leg extension power and unilateral isometric knee extension and flexion torque were determined. All variables were normalised to body mass, and six independent variables ([Formula: see text], CSAs of thigh muscles, leg extension power and knee extension and flexion torque) were entered into a forward stepwise multiple regression model with MPO being dependent variable for males and females separately. In the males, [Formula: see text] was chosen as the single predictor of MPO explaining 78% of the variance. In the females, MPO was attributed to, in the order of importance, [Formula: see text] (p < 0.001) and the CSA of QF (p = 0.011) accounting for 84% of the variance. This study suggests that while oxygen transport capacity is the main determinant of MPO regardless of sex, thigh muscle size also has a role in whole-body maximal aerobic performance in female athletes.

Advanced-sectioned images obtained by microsectioning of the entire male body.

Realistic two-dimensional (2D) and three-dimensional (3D) applications for anatomical studies are being developed from true-colored sectioned images. We generated advanced-sectioned images of the entire male body and verified that anatomical structures of both normal and abnormal shapes could be visualized in them. The cadaver was serially sectioned at constant intervals using a cryomacrotome. The sectioned surfaces were photographed using a digital camera to generate horizontal advanced-sectioned images in which normal and abnormal structures were classified. Advanced-sectioned images of the entire male body were generated. The image resolution was 3.3 × 3.3 fold better than that of the first sectioned images obtained in 2002. In the advanced-sectioned images, normal and abnormal structures ranging from microscopic (≥0.06 mm × 0.06 mm; pixel size) to macroscopic (≤473.1 mm × 202 mm; body size) could be identified. Furthermore, the real shapes and actual sites of lung cancer and lymph node enlargement were ascertained in them. Such images will be useful because of their true color and high resolution in digital 2D and 3D applications for gross anatomy and clinical anatomy. In future, we plan to generate new advanced-sectioned images of abnormal cadavers with different diseases for clinical anatomy studies.

Correlation between computed tomography, magnetic resonance imaging and cross-sectional anatomy of the head of the guinea pig (Cavia porcellus, Linnaeus 1758).

The current work aimed to study the anatomical features of the guinea pig's head by two medical imaging techniques: computed tomography (CT) and magnetic resonance imaging (MRI), and their correlation with the anatomical cross-sectional images. Six adult healthy guinea pigs were used in the present study. Two heads were imaged by CT scanner and then by MRI. The examined heads were cut sagittally and transversely, and two skulls were macerated. The anatomical features were identified on the anatomical sections and compared with the tomographic and MRI images obtained. Data were presented as three-dimensional reconstructed images of the head. In addition, representative combinations of the sagittal and transverse anatomical sections and the corresponding CT scans and MRI images were also presented. Reconstruction of CT images enabled the visualization of different bony structures and airways of the guinea pig head. In addition, skull bones were easily visualized on CT scans, while different parts of the brain were identified on MRI images. Air cavities could be identified by their different contrast on the CT scans and their low intensity on MRI images. The study showed that guinea pig had poorly developed paranasal sinus system represented by rostral and caudal maxillary sinuses. On the contrary, the guinea pig had two tympanic bullae: a small dorsal and a large ventral bulla. In conclusion, this study provides one of the first investigations that uses the multislice CT scans and MRI to study the guinea pig's head and their correlation with the corresponding anatomical sections.

Multimodal Three-Dimensional Visualization Enhances Novice Learner Interpretation of Basic Cross-Sectional Anatomy.

While integrated delivery of anatomy and radiology can support undergraduate anatomical education, the interpretation of complex three-dimensional spatial relationships in cross-sectional and radiological images is likely to be demanding for novices. Due to the value of technology-enhanced and multimodal strategies, it was hypothesized that simultaneous digital and physical learning could enhance student understanding of cross-sectional anatomy. A novel learning approach introduced at a United Kingdom university medical school combined visualization table-based thoracic cross-sections and digital models with a three-dimensional printed heart. A mixed-method experimental and survey approach investigated student perceptions of challenging anatomical areas and compared the multimodal intervention to a two-dimensional cross-section control. Analysis of seven-point Likert-type responses of new medical students (n = 319) found that clinical imaging (mean 5.64 SD ± 1.20) was significantly more challenging (P < 0.001) than surface anatomy (4.19 ± 1.31) and gross anatomy (4.92 ± 1.22). Pre-post testing of students who used the intervention during their first anatomy class at medical school (n = 229), identified significant increases (P < 0.001) in thoracic cross-sectional anatomy interpretation performance (mean 31.4% ± 15.3) when compared to the subsequent abdominal control activity (24.1% ± 17.6). Student test scores were independent of mental-rotation ability. As depicted on a seven-point Likert-type scale, the intervention may have contributed to students considering cross-sectional interpretation of thoracic images (4.2 ± 1.23) as significantly less challenging (P < 0.001) than comparable abdominal images (5.59 ± 1.14). These findings could have implications for how multimodal cross-sectional anatomy learning approaches are implemented within medical curricula.

Genetic factors contributing to late adverse musculoskeletal effects in childhood acute lymphoblastic leukemia survivors.

BACKGROUND: A substantial number of survivors of childhood acute lymphoblastic leukemia (ALL) suffer from treatment-related late adverse effects. While multiple studies have identified the effects of chemotherapeutics and radiation therapy on musculoskeletal outcomes, few have investigated their associations with genetic factors. METHODS: Here we analyzed musculoskeletal complications in relation to common and rare genetic variants derived through whole-exome sequencing of the PETALE cohort. Top-ranking associations were further assessed through stratified and multivariate analyses. RESULTS: DUOX2 variant was associated with skeletal muscle function deficit, as defined by peak muscle power Z score ≤ -2 SD (P = 4.5 × 10-5 for genotyping model). Upon risk stratification analysis, common variants in the APOL3, COL12A1, and LY75 genes were associated with Z score ≤ -2 SD at the cross-sectional area (CSA) at 4% radial length and lumbar bone mineral density (BMD) in high-risk patients (P ≤ 0.01). The modulation of the effect by risk group was driven by the interaction of the genotype with cumulative glucocorticoid dose. Identified variants remained significant throughout multivariate analyses incorporating non-genetic factors of the studied cohort. CONCLUSION: This exploratory study identified novel genetic variants associated with long-term musculoskeletal impairments in childhood ALL survivors. Replication in an independent cohort is needed to confirm the association found in this study.

Prediction of carpal tunnel syndrome using the thenar muscle cross-sectional area by magnetic resonance imaging.

ABSTRACT: Carpal tunnel syndrome (CTS) is a common neuropathy. Although CTS progression is known to be associated with thenar muscle (TM) atrophy, the diagnostic value of TM atrophy for CTS has not been established. In this research, the thenar muscle cross-sectional area (TMCSA) was evaluated to analyze the relationship between the TMCSA and CTS. We assumed that TMCSA is a major diagnostic parameter in the CTS.Both TMCSA and thenar muscle thickness (TMT) samples were acquired from 18 CTS patients, and from 18 control subjects who underwent wrist magnetic resonance imaging with no evidence of CTS. T2-weighted transverse magnetic resonance imaging images were obtained. We measured the TMCSA and TMT at the level of first carpometacarpal joint.The average TMCSA was 296.98 ±â€Š49.39 mm2 in the normal group and 203.36 ±â€Š72.13 mm2 in the CTS group. The average TMT was 8.54 ±â€Š1.45 mm in the normal group and 7.38 ±â€Š1.14 mm in the CTS group. CTS group had significantly lower TMCSA and TMT. Receiver operator characteristics curve analysis showed that the best cutoff point for the TMCSA was 260.18 mm2, with 77.8% sensitivity, 77.8% specificity. The best cutoff point of the TMT was 7.70 mm, with 61.1% sensitivity, 66.7% specificity.Although the TMCSA and TMT were both significantly associated with CTS, the TMCSA was a much more sensitive measurement parameter. Thus, to evaluate CTS patients, the physician should more carefully inspect the TMCSA than TMT.

Study of Sexual Dimorphism in Metatarsal Bones: Geometric and Inertial Analysis of the Three-Dimensional Reconstructed Models.

The aim of the present paper is to determine the sex of the individual using three-dimensional geometric and inertial analyses of metatarsal bones. Metatarsals of 60 adult Chinese subjects of both sexes were scanned using Aquilion One 320 Slice CT Scanner. The three-dimensional models of the metatarsals were reconstructed, and thereafter, a novel software using the center of mass set as the origin and the three principal axes of inertia was employed for model alignment. Eight geometric and inertial variables were assessed: the bone length, bone width, bone height, surface-area-to-volume ratio, bone density, and principal moments of inertia around the x, y, and z axes. Furthermore, the discriminant functions were established using stepwise discriminant function analysis. A cross-validation procedure was performed to evaluate the discriminant accuracy of functions. The results indicated that inertial variables exhibit significant sexual dimorphism, especially principal moments of inertia around the z axis. The highest dimorphic values were found in the surface-area-to-volume ratio, principal moments of inertia around the z axis, and bone height. The accuracy rate of the discriminant functions for sex determination ranged from 88.3% to 98.3% (88.3%-98.3% cross-validated). The highest accuracy of function was established based on the third metatarsal bone. This study showed for the first time that the principal moment of inertia of the human bone may be successfully implemented for sex estimation. In conclusion, the sex of the individual can be accurately estimated using a combination of geometric and inertial variables of the metatarsal bones. The accuracy should be further confirmed in a larger sample size and be tested or independently developed for distinct population/age groups before the functions are widely applied in unidentified skeletons in forensic and bioarcheological contexts.

Morphological characteristics of the forebrain in the donkey (Equus asinus): A compared atlas of magnetic resonance imaging and cross-sectional anatomy.

The brain is the most essential part of the central nervous system which regulates and coordinates all body activities. Based on its phylogenetic development from the neural tube, the brain is divided into rhombencephalon (hindbrain), mesencephalon (midbrain) and prosencephalon (forebrain). The present study is achieved to describe the morphological characteristics of the normal forebrain in the donkey using the matched magnetic resonance imaging (MRI) and cross-sectional anatomy. Ten cadaveric heads of healthy adult donkeys of both sexes were used. Two heads were examined using a 1.5 Tesla MRI scanner, and the brains of the other heads were gently extracted; six brains were sectioned into transverse, dorsal and sagittal slices, and two brains were grossly inspected. MR images were selected in correlation to their closely corresponding gross sections. Both cross-sectional anatomy and MRI scans showed extensive gyration of the neocortex. The forebrain structures appeared with variable intensities on three sequences, Flair, T1-weighted and T2-weighted MRI, enabling comprehensive evaluation of the relevant neuroanatomical structures. The present study provided a precise neuroanatomical atlas of the forebrain in the donkey which could help in the quick and efficient interpretation of clinical diseases of the forebrain, localization of the forebrain functions and evolutionary neurobiology.

Diet and erythrocyte metal concentrations in early pregnancy-cross-sectional analysis in Project Viva.

BACKGROUND: Dietary sources of metals are not well established among pregnant women in the United States. OBJECTIVE: We aimed to perform a diet-wide association study (DWAS) of metals during the first trimester of pregnancy. METHODS: In early pregnancy (11.3 ± 2.8 weeks of gestation), 1196 women from Project Viva (recruited 1999-2002 in eastern Massachusetts) completed a validated FFQ (135 food items) and underwent measurements of erythrocyte metals [arsenic (As), barium, cadmium, cesium (Cs), copper, mercury (Hg), magnesium, manganese, lead (Pb), selenium (Se), zinc]. The DWAS involved a systematic evaluation and visualization of all bivariate relations for each food-metal combination. For dietary items with strong associations with erythrocyte metals, we applied targeted maximum likelihood estimations and substitution models to evaluate how hypothetical dietary interventions would influence metals' concentrations. RESULTS: Participants' mean ± SD age was 32.5 ± 4.5 y and prepregnancy BMI was 24.8 ± 5.4 kg/m2; they were mostly white (75.9%), college graduates (72.4%), married or cohabitating (94.6%), had a household income >$70,000/y (63.5%), and had never smoked (67.1%). Compared with other US-based cohorts, the overall diet quality of participants was above average, and concentrations of erythrocyte metals were lower. The DWAS identified significant associations of several food items with As, Hg, Pb, Cs, and Se; for example, As was higher for each SD increment in fresh fruit (11.5%; 95% CI: 4.9%, 18.4%), white rice (17.9%; 95% CI: 9.4%, 26.9%), and seafood (50.9%; 95% CI: 42.8%, 59.3%). Following the guidelines for pregnant women to consume ≤3 servings/wk of seafood was associated with lower As (-0.55 ng/g; 95% CI: -0.82, -0.28 ng/g) and lower Hg (-2.67 ng/g; 95% CI: -3.55, -1.80 ng/g). Substituting white rice with bread, pasta, tortilla, and potato was also associated with lower As (35%-50%) and Hg (35%-70%). CONCLUSIONS: Our DWAS provides a systematic evaluation of diet-metals relations. Prenatal diet may be an important source of exposures to metals.

Cross-sectional area reference values for high-resolution ultrasonography of the upper extremity nerves in healthy Asian adults.

ABSTRACT: In this study, multiple-site, cross-sectional area (CSA) reference values were established for major peripheral nerves, including small branches, in the upper extremity of a healthy Asian population.This study included 107 prospectively recruited age-matched, healthy subjects with a mean age of 46 years (range, 24-75 years). All subjects underwent standardized nerve conduction studies for the median, ulnar, peroneal, posterior tibial, and sural nerves. CSA was measured unilaterally at 21 sites of the median, ulnar, radial, posterior interosseous, superficial radial sensory, musculocutaneous, lateral antebrachial cutaneous, and medial antebrachial cutaneous nerves.According to their age, the subjects were assigned to the younger group (20-40 years, n = 40), the middle group (40-59 years, n = 40), and the older group (60-80 years, n = 27). The significant differences of CSA values between age groups were found only at certain sites, such as the median (wrist, P = .003), ulnar (medial epicondyle, P = .031; forearm, P = .022), radial (antecubital fossa, P = .037), and superficial radial sensory nerve (P = .028). The CSA significantly correlated with gender, height, weight, and body mass index.This study provides CSA reference values for nerves, including small sensory nerves in the upper extremity, which can be useful in the ultrasonographic investigation of various peripheral neuropathies in the upper extremity.

Age-Related Differences in White Matter: Understanding Tensor-Based Results Using Fixel-Based Analysis.

Aging is associated with widespread alterations in cerebral white matter (WM). Most prior studies of age differences in WM have used diffusion tensor imaging (DTI), but typical DTI metrics (e.g., fractional anisotropy; FA) can reflect multiple neurobiological features, making interpretation challenging. Here, we used fixel-based analysis (FBA) to investigate age-related WM differences observed using DTI in a sample of 45 older and 25 younger healthy adults. Age-related FA differences were widespread but were strongly associated with differences in multi-fiber complexity (CX), suggesting that they reflected differences in crossing fibers in addition to structural differences in individual fiber segments. FBA also revealed a frontolimbic locus of age-related effects and provided insights into distinct microstructural changes underlying them. Specifically, age differences in fiber density were prominent in fornix, bilateral anterior internal capsule, forceps minor, body of the corpus callosum, and corticospinal tract, while age differences in fiber cross section were largest in cingulum bundle and forceps minor. These results provide novel insights into specific structural differences underlying major WM differences associated with aging.