Analysis Of Artery Blood Flow Research Articles

A comparative analysis of arterial blood flow in unexplained infertility, tubal infertility and fertile groups

We aimed to compare ovarian (O), uterine (U) and spiral (S) artery (A) resistance of patients diagnosed as fertile, unexplained infertility (UI) and tubal factor infertility (TFI) in the peri-implantation period and independent from the impact of the treatment. UI (n = 70), TFI (n = 75) and fertile (n = 72) patients’ ovarian, uterine and spiral artery pulsatility index (PI), resistance index (RI) and the endometrial thickness, serum estradiol and progesterone levels were compared. The specificity and sensitivity values were calculated according to determined cutoff values. Both TFI and control groups’ UA PI values were significantly lower than the UI group’s PI values. The highest UA RI values were found in UI group and the lowest values were in the control group. UI and TFI groups’ OA PI/RI values were significantly higher than the control group. Both the control and TFI groups’ SA PI/RI values were significantly lower than UI group’s PI/RI values. UI patients’ uterine and spiral arteries PI values >1.86 and >0.85, RI values >0.80 and >0.53 can be used as a valuable test showing reduced uterine perfusion. Ovarian artery PI values >0.96 and RI values >0.58 can be used as tests showing decreased ovarian perfusion in patients with TFI. In these patients, embryo cryopreservation can be considered.

Frame-rate analysis of arterial blood flow in human and rat using laser speckle image sensing

In imaging of blood flow by means of a laser speckle technique, we have proposed so far an estimation parameter based on the spatial contrast of speckle patterns observed for the blood flow in skin tissue and a blood vessel. This parameter enable us to image a relative blood flow distribution from a single speckle pattern, thus, it analyzes the blood flow with a frame-rate of an imaging device used. In this study, we investigated availability of this parameter for detecting changes in arterial blood flow caused by medication and cold stimulation to the skin tissue. Experiments were conducted for an anesthetized rat and a human wrist to confirm the feasibility of the present parameter.

Modeling blood flow in the arterial system

The investigation of arterial blood flow has always been an important topic in physiology. Large proportion of the cardiovascular diseases (arteriosclerosis, vasoconstriction) affects the arterial part of the circulatory system. Physiologists place huge efforts in the improvement of the diagnosis and the treatment of these diseases. During the last decades fluid mechanics has become a powerful tool in the analysis of arterial blood flow. In the current paper a numerical approach for the calculation of one dimensional unsteady blood flow in the arterial network is presented. The continuity and momentum equations are solved using the method of characteristics (MOC). Furthermore a viscoelastic material model is applied to describe the behavior of the arterial walls. The network model of the arterial system is set up using 45 viscoelastic branches. The heart is modeled using an unsteady volume flow rate boundary condition. Arterioles and capillaries are treated as linear resistance boundary conditions. The parame ters of the viscoelastic material model were fine-tuned by comparing the results of the calculation with previously measured blood pressure curves. The resulting model is capable for simulating arteriosclerosis in an arbitrary part of the arterial network. The viscoelastic material model and the calculation method are presented in detail. Results of the calculation are presented and discussed.

Hemodynamic Analysis of Arterial Blood Flow in the Coiled Umbilical Cord

The most significant anatomical structure of the umbilical cord is its level of coiling. The coiled geometry of the umbilical cord largely affects umbilical blood flow that is vital for fetus's well-being and normal development. In this study, we developed a computational model of steady blood flow through the coiled structure of an umbilical artery. The results showed that the driving pressure for a given blood flow rate is increasing as the number of coils in cord structure increases. The driving gradient pressures also vary with the pitch that dictates the coils' spreading. The coiled structure is resulting in interwoven streamlines along the helix and wall shear stresses (WSS) with significant spatial gradients along the cross-sectional perimeter anywhere within the helical coil. These gradients may have an adverse effect on the development of the fetus cardiovascular system in cases with over coiling (OC) or under coiling (UC) characteristics. The number of coils does not affect the distribution and levels of WSS. However, when the coils are more spread (eg, larger pitch number), the maximal WSS is significantly smaller. Cases with twisted and OC cords seem to yield very large values and gradients of WSS, which may place the fetus into high risk of abnormal development.