T2-weighted turbo spin-echo magnetic resonance imaging of canine brain anatomy at 1.5T, 3T, and 7T field strengths.

Post-mortem T2 weighted images of canine heads were acquired at 1.5T, 3T, and 7T. This study aimed to (1) identify anatomical structures of the canine brain using an ultra-high-field magnetic resonance imaging (MRI) (7T) to help to facilitate their localization on high field MRI images (3T and 1.5T), where these structures may appear less well defined and delineated and (2) evaluate the visibility of canine brain anatomical structures on 1.5T, 3T, and 7T MRI images for optimizing clinical utility. Our hypothesis was that the provided subjective image quality comparison at different field strengths may offer a general baseline for canine brain anatomy and may help clinicians evaluate MRI options better. Six canine heads were examined with 1.5T, 3T, and 7T MRI scanners. T2-weighted images were acquired in three orthogonal planes at each field strength using a turbo spin-echo sequence. Fifty neuroanatomic structures were identified and evaluated on the 7T MR images; subsequently, those were found on the 3T and 45 out of the 50 structures were detected on the 1.5T imaging. The structures that were not able to be identified on the 1.5T imaging included the septum pellucidum, oculomotor nucleus, substantia nigra, claustrum, and thalamic nucleus griseus. Images acquired at 7T were subjective of higher spatial and contrast resolution. However, the ultra-high-field images were prone to artifacts at the interface between tissues of different magnetic properties. In conclusion, 3T MR imaging appears to be the best comprise for evaluating canine brain anatomy on MRI with fewer imaging artifacts.

Neuroanatomical Reconstruction of the Canine Visual Pathway Using Diffusion Tensor Imaging.

The first anatomical atlas of diffusion tensor imaging (DTI) of white matter pathways in the canine brain was published in 2013; however, the anatomical orientation of the entire visual pathway in the canine brain, from the retina to the cortex, has not yet been studied using DTI. In the present study, 3T DTI magnetic resonance (MR) images of three dogs euthanized for reasons other than neurological disorders were obtained. The process of obtaining combined fractional anisotropy and directional maps was initiated within 1 h of death. The heads were amputated immediately after MR imaging and stored in 10% formalin until dissection and histological sampling was performed. The trajectory of the visual pathway is dissimilar to the horizontal representation in other literature. To our knowledge, ours is the first study to visualize the entire canine visual pathway in its full antero-posterior extension. Fibers from the retina to the cortex passed through the optic nerve, optic chiasm, optic tracts, lateral geniculate nucleus, Meyer's and Baum's loops, and pretectal fibers. Their projections to the cortex were similar to those in the human visual pathway. The crossing of fibers at the optic chiasm occurred in 75% of fibers. In addition to advancing our knowledge in this field of study, these results could help plan neurosurgical and radiotherapeutic procedures to avoid unnecessary damage to the visual fiber system.

Self-perceived fatigue in adolescents in relation to body composition and physical outcomes.

BackgroundIncreased self-perceived fatigue (SpF) has already been identified in chronic conditions such as obesity, but it is also a growing problem in school-attending adolescents (±25%). This study tried to link body composition to SpF and physical activity/performance. Additionally, indicators for fatigue were determined.MethodsA total of 452 adolescents were recruited. Body composition was measured and physical activity, physical performance, and SpF were assessed. Based on the total SpF (Multidimensional Fatigue Inventory) outcomes, three groups were created: low fatigue (LF) medium fatigue (MF) and high fatigue (HF).ResultsFat was significantly lower in the LF group compared with MF (P<0,05) and HF (P<0.01). Grip endurance was increased in LF (P<0.05) and MF (P<0.01) compared with HF; similar results were found with the Cooper test. Sport Index was increased in LF compared with MF and HF (P<0.01). Fat and physical activity were related to fatigue (P<0.01). Decreased fatigue resistance, Sport Index and higher fat percentage increased the chance of being extremely fatigued.ConclusionThis study emphasizes the importance of using fat mass and fat percentage instead of body mass index when screening adolescents. To prevent increased SpF, it is necessary to stimulate youngsters to be physically active and to promote healthy behaviors.

Reliability of standard circumferences in domain-related constitutional applications.

OBJECTIVES: There may be no doubt that circumferences, measured at different sites of body segments, have a variety of applications. Studies using girths are based on assumed logic, but within a general context no literature is found as to the origin of choice of a particular circumference for a particular application. The purpose of this study is to relate each circumference (i) with the segmental tissue masses and (ii) with all whole-body tissue masses; in order to provide a complete constitutional reliability report of each girth available. METHODS: Subsequent to an anthropometric protocol, 23 (9 male aged 74.8 ± 5.7 years and 14 female aged 79.2 ± 7.3 years) well-preserved white Caucasian cadavers, of lean subjects were dissected according to the 5-component model and expressed on its tissue-system level, for example, skin, muscle, adipose tissue, viscera, and bones. RESULTS: The relations range from r = 0.80 to r = 0.99 (P < 0.01). A majority of circumferences (e.g., head, neck, upper thigh, mid-thigh, and calf) do represent what is expected. Other girths (e.g., waist, upper arm, elbow, forearm, and wrist) do not relate adequately to the assumed constituent. CONCLUSION: This study suggests the appreciation of the waist circumference. This measure is not valid for lean individuals, but might be for the obese. It is suggested likewise that a combination of chest and hip circumference may have a more general application within the public health sector. In summary, evidence confirms the reliability of a series of circumferences but creates doubts or rejects other colloquially established perimeters.

Assessment of regional adipose tissue depots: a DXA and CT comparison in cadavers of elderly persons.

OBJECTIVE: Since dual energy X-ray absorptiometry (DXA) cannot distinguish between different adipose tissue (AT) deposits, it remains unclear how DXA-derived body composition variables relate to anatomical tissue (sub)compartments. The aim of the present study was to compare and relate regional DXA variables with absolute tissue masses obtained by computer tomography (CT) scanning of the lower limbs in elderly persons. METHODS: Eleven well-preserved white Caucasian adults (seven male and four female cadavers) with a median age of 79.0 years (ranging from 68 to 96 years) were fully scanned with DXA and CT. Separate densities of skin tissue, AT, muscle tissue and bone were obtained by hydrostatic weighing. RESULTS: The leg DXA-variables were significantly related (rho-values between 0.60 and 0.98, P < 0.01) to CT-derived tissue counterparts, but showed significant systematic differences except for subcutaneous AT mass (P = 0.773). After controlling for other AT depots, fat as measured by DXA (fat(DXA)) related only to intermuscular AT (rho = 0.82, P < 0.01) in males and to subcutaneous AT (rho = 0.84, P < 0.05) in females. CONCLUSION: Although significantly interrelated, DXA and CT variables should not be used interchangeably since they have different quantitative and physiological significance. Our results suggest that fat(DXA) represents different parts of AT depots in elderly men and women. Since DXA is not appropriate for assessing tissue variability cautious clinical interpretation is warranted.

Accuracy and concordance of anthropometry for measuring regional fat distribution in adults aged 20-55 years.

OBJECTIVES: This study aimed to assess the accuracy and concordance of anthropometrically derived prediction equations for the estimation of regional fat mass (FM) distribution. METHODS: Sixty-two white males and 50 females with a large range of age (20-55 years) and BMI (16.6-33.4 kg/m(2)) were included. Whole body dual energy X-ray absorptiometry (DXA) scans were acquired and anthropometric prediction equations for regional FM were developed and cross-validated. On the basis of the total sample two anthropometrically derived indices of FM distribution [Formula: see text] ratio and [Formula: see text] ratio were compared with their DXA analogues. RESULTS: In both sexes multiple linear regression models predicted the regional DXA fat masses with good accuracy (P < 0.001). In men mean bias (limits of agreement) were: -6.8 g (-535,364) for FM(arms), 65 g (-1921,2052) for FM(trunk), -21 g (-1374,1332) for FM(legs), -0.2% (-5.0,4.7) for %FM(trunk) and -0.5% (-6.8,5.8) for %FM(legs). In women mean difference (limits of agreement) were: -86 g (-463,450) for FM(arms), 30 g (-1784,1844) for FM(trunk), -278 g (-1782,1227) for FM(legs), 0.4% (-5.5,6.3) for %FM(trunk), and 0.3% (-8.3,8.9) for %FM(legs). No systematic (constant and proportional) differences between methods for the determination of FM distribution ratios were found, suggesting method interchangeability. The concordance for subject classification based on t-scores according to the National Health and Nutrition Examination Survey (NHANES) was significant (P < 0.001), with substantial agreement for [Formula: see text] ratio (κ(w) = 0.80) and [Formula: see text] ratio (κ(w) = 0.75). CONCLUSION: Anthropometric variables offer promise to the development of simple, noninvasive, and inexpensive screening to identify individuals with abnormal FM distribution. The anthropometrically derived indices of FM distribution demonstrate sufficient accuracy for clinical use. Am. J. Hum. Biol., 2013. © 2012 Wiley Periodicals, Inc.

Cross-sectional content analysis of clinically applied circumferences.

BACKGROUND: The contours of a human body are determined by the volumes of the underlying tissues [adipose tissue (AT), muscle, bone and viscera]. Conceptually, they are assumed to be used as a concentric set of cylinders. Determination of these clinically applied circumferences in terms of relative tissue proportions has led to conflicting results. As it remains unclear what a circumference really measures or represents and how it relates to body composition (BC), the aim of this study was to determine the content of the circumferences and whether these perimeters can be used to assess segmental or whole body tissue components. DESIGN: Subsequent to an anthropometric protocol, the five white Caucasian cadavers were fractionated into slices of 3 cm and segmental and whole BC was determined at the anatomical tissue-system level by direct dissection. RESULTS: Only two circumferences correlated significantly with their dominating component [upper arm circumference (r = 0·98; P < 0·01) and waist circumference (WC) (r = 0·90; P < 0·05) with AT]. Two circumferences were related to a segmental tissue component [WC (r = 1·00; P < 0·001) with muscle mass of the trunk and wrist circumference (WrC) (r = 0·90; P < 0·05) with bone mass of the upper limb]. Two circumferences were related to a whole body tissue component [chest circumference (r = 0·90; P < 0·05) with whole body AT mass and WrC (r = 0·90; P < 0·05) with whole body bone mass]. CONCLUSION: The clinically applied circumferences do not measure what they pretend to measure. Of all the studied circumferences, only 2 circumferences (WC and WrC) can be used to assess segmental or whole body tissue components.

Prediction of segmental lean mass using anthropometric variables in young adults.

The aim of the present study was to develop and cross-validate anthropometrical prediction equations for segmental lean tissue mass (SLM). One hundred and seventeen young healthy Caucasians (67 men and 50 women; mean age: 31.9 ± 10.0 years; Body Mass Index: 24.3 ± 3.2 kg · m(-2)) were included. Body mass (BM), stretch stature (SS), 14 circumferences (CC), 13 skinfolds (SF) and 4 bone breadths (BB) were used as anthropometric measurements. Segmental lean mass of both arms, trunk and both legs were measured by dual energy X-ray absorptiometry as the criterion method. Three prediction equations for SLM were developed as follows: arms = 40.394(BM) + 169.836(CCarm-tensed) + 399.162(CCwrist) - 85.414(SFtriceps) - 39.790(SFbiceps) - 7289.190, where Adj.R (2) = 0.97, P < 0.001, and standard error of estimate (SEE) = 355 g;trunk = 181.530(BM) + 155.037(SS) + 534.818(CCneck) + 175.638(CCchest) - 88.359(SFchest) - 147.232(SFsupraspinale) - 46522.165, where Adj.R(2) = 0.97, P < 0.001, and SEE = 1077g; and legs = 55.838(BM) + 88.356(SS) + 235.579(CCmid-thigh) + 278.595(CCcalf) + 288.984(CCankle) - 84.954(SFfront-thigh) - 53.009(SFmedial calf) - 28522.241, where Adj.R (2) = 0.96, P < 0.001, and SEE = 724 g. Cross-validation statistics showed no significant differences (P < 0.05) between observed and predicted SLM. Root mean squared errors were smallest for arms (362 g), followed by legs (820 g) and trunk (1477 g). These new prediction equations allow an accurate estimation of segmental lean mass in groups of young adults, but estimation errors of 8 to 14% can occur in certain individuals.

Reproducibility, accuracy and concordance of Accutrend Plus for measuring circulating lipid concentration in adults.

INTRODUCTION: The determination of lipid biomarkers by capillary sampling may be useful in the screening, diagnosis and/or personal management of hyperlipidemia and cardiovascular risk. It remains unclear whether the use of the Accutrend Plus system is appropriate. This study aimed to assess its reproducibility, accuracy and concordance for blood lipid profiling in adults. MATERIALS AND METHODS: Fasting capillary total cholesterol (TC) and triglyceride (TG) concentration on Accutrend Plus were compared with their venous analogues obtained by a laboratory reference method in sixty-one adults (27 men and 34 women, aged 33.0 years). Supplementary capillary sampling was performed at two consecutive days taking into account macro-nutrient intake. RESULTS: The day-to-day reproducibility of the Accutrend Plus system proved to be high for TC (ICC = 0.85, P < 0.001), but moderate for TG (ICC = 0.68, P < 0.001). Strong correlations (r > or = 0.80, P < 0.001) with the reference method were found for TC and TG. Mean difference (limits of agreement) were: 0.26 mmol/L (-0.95, 1.47) for TC, and -0.16 mmol/L (-1.29, 0.98) for TG. The concordance for subject classification according to the National Cholesterol Education Program (NCEP) guidelines was significant (P < 0.001), with substantial agreement for TC (K(w) = 0.67), and moderate agreement for TG (K(w) = 0.50). CONCLUSIONS: Day-to-day reproducibility of the Accutrend Plus device for TC and TG is not optimal and lacks accuracy when compared to the reference laboratory method. The concordance between both methods for classifying subjects according to the NCEP is inadequate. Accutrend Plus device should not be interchangeably used as a substitution for the standard laboratory methods in the diagnosis of hyperlipidemia.

Comparison of frequently used, unexplored and newly designed indices for the assessment of segmental and whole body constituents.

Many constitutional indices, used as screening parameters in public health, have been explored (in-vivo) and applied for many years, but as yet there is no consensus on a universal index. This reflects confusion, or at least lack of agreement, about what a constitutional index should represent. The aim of this study was to explore the direct relationship of frequently used, unexplored and newly designed indices with adipose tissue masses and trunk adipose tissue distribution, on an anatomical 5-component model. Whole body and trunk composition, of 28 white Caucasian cadavers (aged 78.4±6.9 years), were determined at the anatomical tissue-system level by direct dissection. In the male group, the body mass index, the height/3body volume index and the weight/height-waist circumference-depth index showed good to excellent significant correlations with all adipose tissue masses (r-values between 0.75 and 0.92) and with the internal adipose tissue/adipose tissue ratio (r-values between 0.59 and 0.78). In the female group, the body mass index, the height/3body volume index and the weight/height-waist circumference index showed moderate to excellent significant correlations with all adipose tissue masses (r-values between 0.58 and 0.87) and with the internal adipose tissue/adipose tissue ratio (r-values between 0.52 and 0.80) and the internal adipose tissue/subcutaneous adipose tissue ratio (r-values between 0.48 and 0.78). The findings suggest that the newly designed indices (e.g. weight to height-waist circumference-depth index in males and weight to height-waist circumference index in females) are better correlates of whole body adipose tissue masses and trunk adipose tissue distribution than the frequently used indices.

Critical appraisal and hazards of surface electromyography data acquisition in sport and exercise.

The aim of this critical appraisal and hazards of surface electromyography (SEMG) is to enhance the data acquisition quality in voluntary but complex movements, sport and exercise in particular. The methodological and technical registration strategies deal with telemetry and online data acquisition, the placement of the detection electrodes and the choice of the most adequate normalization mode.Findings compared with the literature suggest detection quality differences between registration methods and between water and air data acquisition allowing for output differences up to 30% between registration methods and up to 25% decrease in water, considering identical measures in air and in water. Various hazards deal with erroneous choices of muscles or electrode placement and the continuous confusion created by static normalization for dynamic motion. Peak dynamic intensities ranged from 111% (in archery) to 283% (in giant slalom) of a static 100% reference. In addition, the linear relationship between integrated EMG (IEMG) as a reference for muscle intensity and muscle force is not likely to exist in dynamic conditions since it is muscle - joint angle - and fatigue dependent. Contrary to expectations, the literature shows 30% of non linear relations in isometric conditions also.SEMG in sport and exercise is highly variable and different from clinical (e.g. neurological) EMG. Choices of electrodes, registration methods, muscles, joint angles and normalization techniques may lead to confusing and erroneous or incomparable results.