Estimating body segment parameters from three-dimensional human body scans

Body segment parameters are inputs for a range of applications. Participant-specific estimates of body segment parameters are desirable as this requires fewer prior assumptions and can reduce outcome measurement errors. Commonly used methods for estimating participant-specific body segment parameters are either expensive and out of reach (medical imaging), have many underlying assumptions (geometrical modelling) or are based on a specific subset of a population (regression models). Our objective was to develop a participant-specific 3D scanning and body segmentation method that estimates body segment parameters without any assumptions about the geometry of the body, ethnic background, and gender, is low-cost, fast, and can be readily available. Using a Microsoft Kinect Version 2 camera, we developed a 3D surface scanning protocol that enabled the estimation of participant-specific body segment parameters. To evaluate our system, we performed repeated 3D scans of 21 healthy participants (10 male, 11 female). We used open source tools to segment each body scan into 16 segments (head, torso, abdomen, pelvis, left and right hand, forearm, upper arm, foot, shank and thigh) and wrote custom software to estimate each segment’s mass, mass moment of inertia in the three principal orthogonal axes relevant to the center of the segment, longitudinal length, and center of mass. We compared our body segment parameter estimates to those obtained using two comparison methods and found that our system was consistent in estimating total body volume between repeated scans (male p = 0.1194, female p = 0.2240), estimated total body mass without significant differences when compared to our comparison method and a medical scale (male p = 0.8529, female p = 0.6339), and generated consistent and comparable estimates across a range of the body segment parameters of interest. Our work here outlines and provides the code for an inexpensive 3D surface scanning method for estimating a range of participant-specific body segment parameters.

Control of flow separation over a circular cylinder using synthetic jet

The development of methods of active separation flow control is of great applied importance for many technical and engineering applications. Understanding the conditions for the flow separation from the surface of a bluff body is essential for the design of aircrafts, cars, hydro and gas turbines, bridges and buildings. Drag, acoustic noise, vibrations and active flow mixing depend drastically on the parameters of the vortex separation process. We investigated the possibility of reducing the longitudinal length of a reverse-flow region using the method of «synthetic jet» active separation flow control. The experiment was carried out on a compact straight-through wind channel with a 1-m long test section of a cross-section of 125x125 mm. The jet was placed at the rear stagnation point of a circular cylinder. The Reynolds number, based on the cylinder diameter and the free-stream velocity, was 5000 and the von Kármán street shedding frequency without the synthetic jet was equal to 64.8 Hz. For the first time, for such a set of parameters, we applied high speed PIV to demonstrate that the injection of the synthetic jet into the cylinder wake region leads to a significant reduction in the longitudinal length of the reverse-flow region.

A Nitric Oxide–Modulated Variable-Order Fractional Maxwell Viscoelastic Model of Cerebral Vascular Walls

It is well known that the mechanical behavior of arterial walls plays an important role in the pathogenesis of vascular diseases. Most studies existing in the literature focus on the mechanical interactions between the blood flow and wall’s deformations. However, in the brain, the smaller vessels experience not only oscillatory forces due to the pulsatile blood flow but also structural and morphological changes controlled by the surrounding brain cells. In this study, the mechanical deformation of the cerebral arterial wall caused by the pulsatile blood flow and the dynamics of the neuronal nitric oxide (NO) is investigated. NO is a small diffusive gaseous molecule produced by the endothelial cells and neurons, which is involved in the regulation of cerebral blood flow and pressure. The cerebral vessel is assumed to be a hollow axial symmetric cylinder whose wall thickness is much smaller than the cylinder’s radius and longitudinal length is much less than the propagating wavelength. The wall is an isotropic, homogeneous linear viscoelastic material described by an NO-modulated variable-order fractional Maxwell model. A fractional telegraph equation is obtained for the axial component of the displacement. Patterns of wall’s deformation are investigated through numerical simulations. The results suggest that a significantly decreased inactivation of the neuronal NO may cause a reduction in the shear stress at the blood-vessel interface, which could lead to a decrease in the production of shear-induced endothelial NO and neurovascular disease.

Assessment of intracardiac flow dynamics for the evaluation of patients with different ventricular geometry

Background Over the last decades growing evidence have demonstrated the promising role of intracardiac flow dynamic analysis in evaluating cardiac performance. Diastolic forces contribute to the formation of vortices, complex structures capable of kinetic energy storage and responsible of a smoother transition of blood from left ventricular (LV) inlet to outlet. Change in shape and location of these structures has been related with cardiovascular disease and prognosis. Purpose To investigate quantitative changes in vortices parameters in patients with different ventricular geometry. Methods We enrolled 72 consecutive patients (age 66±11 years, 49 male, 68%) with LV concentric hypertrophy (CH, n=15), eccentric hypertrophy (EH, n=13), concentric remodeling (CR, n=15) and normal LV geometry (CTRL, n=29). Each patient underwent a complete echocardiographic examination and a non-invasive intracardiac fluid dynamic analysis by Color Vector Flow Mapping. A 3-chamber apical view with a frame rate between 22 and 25 Hz has been acquired and subsequently analyzed offline by a semi-automatic software obtaining the following parameters: vortex area (VA) (the ratio between the total vortex area and the left ventricular (LV) area); vortex length (VL) (the longitudinal length of the vortex relative to the total LV length; vortex depth (VD) (the distance of the vortex center from the LV base relative to the total LV long axis). Bland Altman Plot has been used to assess intra and inter-observer variability. Results Mean VD was higher in CR, CH and EH compared to CTRL (p=0.013, p=0.001 and p=0.022, respectively). Moreover, CH showed higher VL (p=0.006) and larger VA (p=0.012) compared to CTRL. A similar trend was noticed in EH patients, despite did not reach statistical significance (p=0.21 and p=0.07 for VA and VL respectively). No significative differences in vortices parameters have been observed between CH and EH. Conclusion(s) This is the first study providing quantitative echocardiographic parameters of vortex location and morphology in different LV geometries. Higher values of VD were found in CR, CH and EG. Quantitative intra dynamic fluid assessment was feasible and reliable in the whole population and could provide additional information to the standard echocardiographic examination. FUNDunding Acknowledgement Type of funding sources: None.

Assessment of intracardiac flow dynamics for the evaluation of patients with aortic stenosis

Background Assessment of intracardiac flows and turbulence has acquired rising significance in the past few years, due to the development and introduction of technologies for non-invasive cardiovascular imaging. Recent studies have shown that alterations in intracardiac fluid dynamics can be helpful to identify abnormalities in cardiac function. Purpose This study investigates the additional information provided by the quantitative assessment of intracardiac flow dynamics for the evaluation of patients with aortic stenosis (AS), by using an advanced echocardiography vortex-based approach. Methods Sixty-one patients with severe AS (33 females) and 38 healthy sex- and BSA-matched controls (CTRL) (15 females) were prospectively included and underwent echocardiographic assessment of intracardiac flow dynamics. Echocardiographic measurements were performed on apical three chamber views. The HyperDoppler software adapted to the echo-scanner without contrast injection was used to assess intracardiac vortex properties. The following parameters were obtained: vortex area (VA) (the ratio between the total vortex area and the left ventricular (LV) area); vortex length (VL) (the longitudinal length of the vortex relative to the total LV length; vortex depth (VD) (the distance of the vortex center from the LV base relative to the total LV long axis). Inter-rater variability was measured using intraclass correlation coefficients (ICCs) between two independent operators. Results Patients with severe AS (mean gradient: 47,5±13,9 mmHg; aortic valve area: 0.7±0.2 cm2; ejection fraction: 53±7%) had increased LV wall thickness (p<0.001) and mass index (p<0.001) compared with controls. Greater indexed left atrial volume (p<0.001), E/e' (p<0.001) and trans-tricuspid gradient (p<0.001) were also observed in the AS group. The assessment of VA, VL and VD was feasible in the whole population. Their calculation was reliable, as ICCs were very good for VA (0.878, p=0.033), VL (0.960, p=0.004) and VD (0,905, p=0.021). Mean VA was significantly larger in patients with severe aortic stenosis compared with CTRL (p=0.033). VL and VD (p=0.026 and p>0.001, respectively) were significantly higher in AS patients compared with CTRL. Among those who underwent TAVR, we observed a significant difference in the delta values of VA and VL pre-postTAVR in patients with and without significant paravalvular leak (p<0.05). Conclusions The newly defined VA, VL and VD, quantitative indices of vortical flow, were significantly increased in the LV cavity of patients with severe AS compared to normal subjects. These indices, whose measurement was feasible and reliable, might provide complementary information to standard echocardiography, useful for the further diagnostic and prognostic characterization of the heterogeneous population of patients with severe AS. FUNDunding Acknowledgement Type of funding sources: None.

The Prevalence Disability resulting from adult acquired Foot Flat Deformity among Middle aged population

Aim: To investigate about the prevalence of disability resulting from adult acquired foot flat deformity (AAFD) among middle aged population. Background: Adult acquired foot flat deformity (AAFD) which is also known as posterior tibialis tendon dysfunction (PTTD) is the condition which leads to pain due to the collapse of the longitudinal (length wise) arch of the foot. Its affects women more than non, peaking age of 55 years. The prevalence of flat foot is uncertain due to the lack of exact clinical or radiographic criteria. The foot structure problem which affects the functional activity in the adult population has been poorly studied. So the present study was undertaken about the prevalence of disability resulting from AAFD which may help to develop preventive approaches, as increased awareness serve to help the patient with earlier referral and treatment by limiting their disability. Methodology: 50 subjects who was diagnosed as AAFD was included in the study based on the inclusion and exclusion criteria. Foot function index score was calculated for the samples. Outcome Measure: Foot function index scale. Results: The total mean score is 112.75. The prevalence of disability resulting from adult acquired foot flat deformity which affects the quality of life for samples taken is 66%.

Sonographic evaluation of spleen size in apparently healthy children in north-west Ethiopia, 2020: time to define splenomegaly

Background Assessment of spleen size is an important part of the clinical skills of medical students and physicians. Many diseases can affect the size of the aforementioned organ, ranging from infective processes to malignant disorders. However, to detect changes, prior knowledge of the actual normal size of these viscera is required in the population being studied. Establishing a customized chart and curve for a specific population of the same sociodemographic characteristics enables a better interpretation of sonographic assessments. Methods A hospital-based cross-sectional study design was conducted among 403 children in primary and referral hospitals of the east and west Gojjam zone. Data were collected using a structured questionnaire, physical examination, and ultrasound. The collected data were entered into Epi Data version 3.1 and exports to SPSS version 24 for analysis. Descriptive data were analyzed using descriptive statistics. A Pearson product-moment correlation was run to determine the relationship between age, anthropometric measurements of children, and ultrasound measurements of the spleen. Reference intervals were established using non-parametric reference limits (2.5th -97.5th ) and (5th – 97th ) percentiles by MedCalc software version 20.0.3. Results Four hundred three children aged from 7 to 15 years were included in this study. The mean sonographic longitudinal (length), anteroposterior(depth) and transverse (width) dimension of the spleen was, (8.24 ± 1.26 cm), (3.98 ± 0.57 cm), and (4.26 ± 0.59 cm) respectively. The mean volume of the spleen was 75.04 ± 23.92 cm3. The height and body surface area of children were best correlated with sonographic dimensions of the spleen. Reference intervals were established using height, age, and body surface area specific for clinically practical dimensions of the spleen. Conclusions According to this study, the children are considered as having enlarged longitudinal dimension of the spleen(splenomegaly) if he or she has a size above 97.5th percentile based on their respective height.

MRI features of ERSA (exercise-related signal abnormality) lesions in professional soccer players

Objective This study aims to describe the prevalence, anatomy and morphology of ERSA (exercise-related signal abnormality) lesions, a previously undescribed pattern of muscle signal changes on MRI in professional soccer players with suspected acute thigh muscle injury. Methods A multicenter retrospective review was performed of 287 MRIs of professional soccer players referred for suspected acute thigh injury from August 2017 to February 2020. MR images were reviewed for muscle signal abnormalities corresponding to a peritendinous ovoid region or a subfascial ring of faint increased signal on fluid-sensitive MR images. Imaging features including anatomical site, morphology, and craniocaudal length were recorded. Concomitant acute muscle injury was graded in accordance with the British Athletics Muscle Injury Classification (BAMIC). Results ERSA lesions comprising a peritendinous ovoid region, a subfascial ring, or both, were identified in 40 muscles across 31/287 studies (10.8%). These lesions had a mean length of 15.8 cm and were predominantly located in the proximal or mid-portions of muscles. Affected muscles were rectus femoris (n = 22), adductor longus (n = 11), semitendinosus (n = 6) and biceps femoris (n = 1). 21/31 studies (67.7%) had a BAMIC grade 1–4 injury in a separate muscle, which were largely (81%) in a separate anatomic compartment or contralateral. Conclusion ERSA lesions were evident on MRI in 10.8% of our cohort of professional soccer players referred for suspected acute thigh muscle injury. Characteristic morphology and the longitudinal length (mean 15.8 cm) distinguish ERSA lesions from recognized patterns of acute muscle injury.

Estimating body segment parameters from three-dimensional human body scans

Body segment parameters are inputs for a range of applications. The estimation of body segment parameters that are participant-specific is desirable as it requires fewer prior assumptions and can reduce outcome measurement errors. Commonly used methods for estimating participant-specific body segment parameters are either expensive and out of reach (medical imaging), have many underlying assumptions (geometrical modelling) or are based on a specific subset of a population (regression models). Our objective was to develop a participant-specific 3D scanning and body segmentation method that estimates body segment parameters without any assumptions about the geometry of the body, ethnic background, and gender, is low-cost, fast, and can be readily available. Using a Microsoft Kinect camera, we developed a 3D surface scanning protocol that estimated participant-specific body segment parameters. To evaluate our system, we performed repeated 3D scans of 21 healthy participants (10 male, 11 female). We used open-source software to segment each body scan into 16 segments (head, torso, abdomen, pelvis, left and right hand, forearm, upper arm, foot, shank and thigh) and wrote custom software to estimate each segment's mass, mass moment of inertia in the three principal orthogonal axes relevant to the center of the segment, longitudinal length, and center of mass. We compared our body segment parameter estimates to those obtained using two comparison methods and found that our system was consistent in estimating total body volume between repeated scans (male p=0.1194, female p = 0.2240), estimated total body mass without significant differences when compared to our comparison method and a medical scale (male p=0.8529, female p = 0.6339), and generated consistent and comparable estimates across all of the body segment parameters of interest. The work here outlines an inexpensive 3D surface scanning approach for estimating a range of participant-specific body segment parameters.

Intestinal endometriotic nodules with a length greater than 2.25 cm and affecting more than 27% of the circumference are more likely to undergo segmental resection, rather than linear nodulectomy

Study objective To analyze the efficacy of intestinal ultrasonography with bowel preparation (TVUSBP) for endometriosis mapping in evaluating intestinal endometriosis to choose the surgical technique (segmental resection or linear nodulectomy) for treatment. Design Cross-sectional observational study. Setting University Hospital—Center for Advanced Endoscopic Gynecologic Surgery from April 2010 to November 2014. Patient(s) One hundred and eleven women with clinically suspected endometriosis and intestinal endometriotic nodule or intestinal adherence in TVUSBP for endometriosis mapping. Intervention(s) All patients with suspected endometriosis underwent TVUSBP for endometriosis mapping prior to videolaparoscopy for complete excision of endometriosis foci, including intestinal foci, using the linear nodulectomy or segmental resection techniques, depending on the characteristics of the intestinal lesion with confirmation of endometriosis on anatomopathological examination. Measurements and main results Preoperative ultrasonographic assessment of the length of the intestinal nodule, circumference of the intestinal loop affected by the endometriotic lesion, distance from the anal verge and intestinal wall layers infiltrated by endometriosis, as well as other endometriosis sites. Of the 111 patients who participated in the study, 63 (56.7%) presented intestinal endometriotic nodules in ultrasonography, performed by a single examiner (A.L.A.N.), and underwent intestinal surgical treatment of deep endometriosis—linear nodulectomy or segmental resection. The analysis of the receiver operating characteristic (ROC) curve showed that a longitudinal length of the intestinal nodule of 2.25 cm and a loop circumference of 27% are cutoff points separating linear nodulectomy from segmental resection techniques for excising intestinal endometriosis. The information obtained by TVUSBP helps the surgeon and patient, in the preoperative period, to select the surgical technique to be performed for resection of intestinal endometriosis and plan the surgical procedure while taking into account postoperative morbidity.