Bone density loss after spinal cord injury - Elite paraplegic basketball players vs. paraplegic sedentary persons

Objective: To compare the bone mineral density of elite paraplegic basketball players with the values obtained from their paraplegic sedentary counterparts. Design: A total of 17 male paraplegic basketball players and 17 male paraplegic sedentary persons were included in the study. Bone mineral densities of the distal third of radius of the dominant arm, L2-L4 spine, and trochanters, Ward's triangles, and the femoral necks of both hips were measured. Results: The densities of trochanters, Ward's triangles, and the femoral necks were found to be decreased in both groups, with no significant difference between them. The densities of lumbar and radial regions were found to be increased in both groups. Radial density was significantly higher in paraplegic basketball players than in paraplegic sedentary patients, whereas the groups were not significantly different for lumbar density. Conclusions: Wheelchair basketball in spinal cord-Injured patients was associated with greater bone density in distal radius compared with sedentary paraplegics. However, it was not associated with greater density below the injury level

Celiac Disease Presenting with Bone Pain: Two Case Reports

Celiac disease or gluten sensitive enteropathy is an autoimmune disease characterized by inflammation of the small-bowel mucosa. As can be asymptomatic, involvement of the hematologic, gastrointestinal system, musculosceletal system, nervous system or endocrine system may occur as well. The presence of osteoporosis in celiac disease, may be the only sign of patients who have not been diagnosed yet. The direct effect of celiac disease on bones happens secondary to decreased absorbsion of calcium and vitamin D. Here, two cases with celiac disease along with ongoing bone pain secondary to osteoporosis presented. (Turkish Journal of Osteoporosis 2011;17:24-5

Large Eddy Simulation of Blood Flow Inside Vessels for Acoustic Diagnosis of Atherosclerosis

Atherosclerosis is a cardiovascular disease, in which plaque builds up inside a blood vessel, narrowing it down and forming a stenosis that adversely affects flow. Because of the constriction, turbulent flow occurs at the post-stenotic region, which leads pressure fluctuations on the vessel wall. The murmur caused by this interaction propagates through the surrounding tissue and reaches the skin surface. These sounds emitted from the stenosed vessels are evaluated as a sign of stenosis. In this study, large eddy simulations are conducted to investigate the turbulence-induced wall pressure fluctuations and resulting acoustic emission. The two main parameters considered for this purpose are the stenosis severity and shape. The results show that stenosis severity under a certain level does not cause disturbance at the post-stenotic region. For constrictions above this critical level, increasing stenosis severity has an intensifying effect on the wall pressure fluctuations. Eccentric stenosis morphology causes more severe fluctuations than the axisymmetric one. Different stenosis shapes affect both the magnitude of fluctuations and the duration in which the fluctuations are intense during the pulsatile cycle. Obtained pressure fluctuations are converted into sound and investigated in terms of sound levels and patterns. Sounds emitted from the vessels with different stenosis severities and shapes have different sound characteristics, and they can provide important information about the constriction. Therefore, both the stenosis severity and the shape must be taken into account for development of an acoustic-based diagnostic system

Damarlardaki Daralmaların Oluşturduğu Akustik Yayılımın Büyük Girdap Benzetimleri ile İncelenmesi

Gerçek hastalardan elde edilmiş sağlıklı damar geometrileri üzerinde literatürden esinlenerek oluşturulacak olan gerçekçi daralmalar içindeki kan akışı OpenFOAM yazılımı ve Büyük Girdap Benzetimi (Large Edy Simulaton, LES) modellemesi ile çözülecek ve daralma sonrası oluşan akustik yayılım detaylı olarak araştırılacaktır. Sabit, sinusoidal atımlı ve fizyolojik atımlı akış koşullarında yapılacak olan çözümlerde su, Newtonsal kan ve Newtonsal olmayan kan kullanılacaktır. Bu sayede daralma geometrisi ve şiddetinin, akışın zamana bağlı değişiminin ve sıvının viskoz özelliğinin akustik yayılıma olan etkisi anlaşılacaktır. Uzun vadeli hedef stenoza maruz kalmış damarlardan yayılan akustik verinin girişimsel olmayan bir şekilde hastalığın teşhisi ve ilerleyişinin takibi için kullanılmasının mümkün olup olmayacağının araştırılmasıdır

Numerical investigation of wall pressure fluctuations downstream of concentric and eccentric blunt stenosis models

Pressure fluctuations that cause acoustic radiation from vessel models with concentric and eccentric blunt stenoses are investigated. Large eddy simulations of non-pulsatile flow condition are performed using OpenFOAM. Calculated amplitude and spatial-spectral distribution of acoustic pressures at the post-stenotic region are compared with previous experimental and theoretical results. It is found that increasing the Reynolds number does not change the location of the maximum root mean square wall pressure, but causes a general increase in the spectrum level, although the change in the shape of the spectrum is not significant. On the contrary, compared to the concentric model at the same Reynolds number, eccentricity leads to an increase both at the distance of the location of the maximum root mean square wall pressure from the stenosis exit and the spectrum level. This effect becomes more distinct when radial eccentricity of the stenosis increases. Both the flow rate and the eccentricity of the stenosis shape are evaluated to be clinically important parameters in diagnosing stenosis

Effect of stenosis shape on the sound emitted from a constricted blood vessel

Effect of stenosis shape on the post-stenotic pressure fluctuations and the sound emitted from a constricted blood vessel is studied numerically. Large eddy simulations are performed using OpenFOAM under pulsatile flow conditions with a non-Newtonian fluid model. Findings indicate that the high slope at the stenosis entrance and overlap of more than one stenosis shorten the length of the flow jet, trigger turbulence, and increase vortical activity, turbulent kinetic energy, and magnitude of pressure fluctuations at the post-stenotic region. Also, these morphological parameters strengthen the audible signal especially in the systolic phase of the pulsatile flow. On the other hand, asymmetry of the stenosis creates an opposite effect. Based on the wall pressure data, it is shown that the stenosis shape affects the intensity and the pattern of the murmurs generated. Stenosis shape is found to be an essential factor for the acoustic-based non-invasive diagnosis of stenosis

Simulation of turbulence induced sound generation inside stenosed femoral artery models with different severities and eccentricities

Background and objectives: Recent developments of low-cost, compact acoustic sensors, advanced signal processing tools and powerful computational resources allow researchers design new scoring systems for acoustic detection of arterial stenoses. In this study, numerical simulations of blood flow inside stenosed arteries are performed to understand the effect of stenosis severity and eccentricity on the turbulence induced wall pressure fluctuations and the generated sound. Methods: Axisymmetric and eccentric elliptic stenoses of five different severities are generated inside a 6.4 mm diameter femoral artery model. Large eddy simulations of pulsatile, non-Newtonian blood flow are performed using the open source software OpenFOAM. Results: Post-stenotic turbulence activity is found to be almost zero for 50 and 60% severities. For severities of 75% and more, turbulent kinetic energy rises significantly with increasing severity. The location of the highest turbulence activity on the vessel wall from the stenosis exit decreases with increasing severity. The maximum level of turbulent kinetic energy seen in 95% severity models is about 9 and 31 times higher than that of 87% and 75% models, respectively. Spectrum of wall pressure fluctuations show that 50 and 60% axisymmetric models are almost silent. The spectrum starts to get richer with 75% severity, and the fluctuation intensity increases with severity. Compared to the axisymmetric models, more activity is observed in the 0–150 Hz band for the 50 and 60% eccentric models. Axial extent of the acoustically active region is also longer in them. Converting wall pressure data into sound revealed that murmurs that can be considered as signs of vascular stenosis are obtained for models with 75% and higher severity. Conclusions: Sound patterns generated from simulation results are similar to the typical sounds obtained by Doppler ultrasonography, and present distinct characters. Together with a sensor technology that can measure these sounds from within the stenosed artery, they can be processed and used for the purpose of non-invasive diagnosis. Computational fluid dynamics studies that simulate large number of cases with different stenosis severities and morphologies will play a critical role in developing the necessary sound databases, which can be used to train new diagnostic devices