Influence of Stent Design on Intraaneurysmal Flow: A PIV Study

2000 ◽  
Author(s):  
V. Livescu ◽  
B. B. Lieber ◽  
L. N. Hopkins ◽  
A. K. Wakhloo
Keyword(s):  
Cardiac Cycle ◽  
Cerebral Arteries ◽  
Temporal Distribution ◽  
Surface Integral ◽  
Parent Vessel ◽  
Image Velocimetry ◽  
Before And After ◽  
The Mean ◽  
Aneurysmal Neck ◽  
Mean Circulation

Abstract Interaction between stents and flow inside a sidewall aneurysm model was investigated using Particle Image Velocimetry (PIV). Three spring-like stents having the same porosity but different filament diameter were placed inside the parent vessel that harbored the aneurysm traversing the aneurysmal neck. The flow field inside the aneurysm was investigated before and after placement of the stents. The flow through model was pulsatile and the hemodynamic conditions were representative for those found in human intracranial and extracranial cerebral arteries. Flow patterns inside the aneurysm were significantly altered after stent placement. To facilitate comparison among all cases, the circulation inside the aneurysm was obtained as the surface integral of the distributed vorticity. The results show that the strength of the circulation is substantially diminished for all stented cases. However, the temporal distribution of the circulation through the cardiac cycle is similar for the three stents considered. Further, the mean circulation over one cardiac cycle was obtained for each case as the integral of the absolute value of the temporal distribution. The mean circulation reveals that noteworthy differences in intraaneurysmal hemodynamics do exist among the filament diameters considered.

scholarly journals Effect of Magnesium Sulfate on Doppler Parameters of Fetal Umbilical and Middle Cerebral Arteries in Women with Severe Preeclampsia

2012 ◽  
Vol 2 ◽  
pp. 85 ◽  
Author(s):  
Nazanin Farshchian ◽  
Negin Rezavand ◽  
Saeed Mohammadi
Keyword(s):  
Magnesium Sulfate ◽  
Doppler Ultrasound ◽  
Color Doppler ◽  
Cerebral Arteries ◽  
Color Doppler Ultrasound ◽  
Severe Preeclampsia ◽  
Resistivity Index ◽  
Middle Cerebral Arteries ◽  
Before And After ◽  
The Mean

Objective: To assess the effect of injecting magnesium sulfate on Doppler parameters of fetal umbilical and middle cerebral arteries (MCA) in women with severe preeclampsia. Materials and Methods: A total of 21 patients with severe preeclampsia admitted to Imam Reza Hospital, Kermanshah (Iran), were evaluated. Before and after administration of magnesium sulfate, Doppler ultrasound scan was carried out to measure fetal middle cerebral artery and umbilical artery blood flow. Paired t-test was used for statistical analysis. Results: After injection of magnesium sulfate, the mean resistivity index (RI)-umbilical, and pulsatility index (PI)-cerebral showed a statistically significant reduction (P < 0.001). The cerebroumbilical C/U ratio increased after the intervention (P < 0.001). The PI-umbilical (P = 0.1) and pre- and post-RI-cerebral (P = 0.96) did not have statistically significant changes. Conclusions: Infusion of magnesium sulfate significantly decreases the flow in the fetus RI-umbilical and PI-MCA, and it increases C/U ratio indices in color Doppler ultrasound.

Hemodynamic Characterization of Geometric Cerebral Aneurysm Templates Treated With Embolic Coils

2016 ◽  
Vol 138 (2) ◽  
Author(s):  
Priya Nair ◽  
Brian W. Chong ◽  
Aprinda Indahlastari ◽  
Justin Ryan ◽  
Christopher Workman ◽  
...  
Keyword(s):  
Cerebral Aneurysms ◽  
Physical Models ◽  
General Level ◽  
Minor Role ◽  
Parent Vessel ◽  
Hemodynamic Responses ◽  
Geometric Factors ◽  
Image Velocimetry ◽  
Before And After ◽  
Embolic Coils

Embolic coiling is one of the most effective treatments for cerebral aneurysms (CAs), largely due to the hemodynamic modifications that the treatment effects in the aneurysmal environment. However, coiling can have very different hemodynamic outcomes in aneurysms with different geometries. Previous work in the field of biofluid mechanics has demonstrated on a general level that geometry is a driving factor behind aneurysmal hemodynamics. The goal of this study was to relate two specific geometric factors that describe CAs (i.e., dome size (DS) and parent-vessel contact-angle (PV-CA)) and one factor that describes treatment (i.e., coil packing density (PD)) to three clinically relevant hemodynamic responses (i.e., aneurysmal root-mean-square velocity (Vrms), aneurysmal wall shear stress (WSS), and cross-neck flow (CNF)). Idealized models of basilar tip aneurysms were created in both virtual and physical forms to satisfy two-level multifactorial experimental designs. Steady and pulsatile flow hemodynamics were then evaluated in the virtual models using computational fluid dynamics (CFD) (before and after virtual treatment with finite element (FE) embolic coil models), and hemodynamics were also evaluated in the physical models using particle image velocimetry (PIV) (before and after treatment with actual embolic coils). Results showed that among the factors considered, PD made the greatest contributions to effects on hemodynamic responses in and around the aneurysmal sac (i.e., Vrms and WSS), while DS made the greatest contributions to effects on hemodynamics at the neck (i.e., CNF). Results also showed that while a geometric factor (e.g., PV-CA) may play a relatively minor role in dictating hemodynamics in the untreated case, the same factor can play a much greater role after coiling. We consider the significance of these findings in the context of aneurysmal recurrence and rupture, and explore potential roles for the proposed methods in endovascular treatment planning.

Effects of subarachnoid hemorrhage from puncture of the middle cerebral artery on blood flow and vasculature of the cerebral cortex in the cat

1971 ◽  
Vol 35 (6) ◽  
pp. 664-671 ◽  
Author(s):  
Takenori Yamaguchi ◽  
Arthur G. Waltz
Keyword(s):  
Blood Flow ◽  
Cerebral Arteries ◽  
Cerebral Hemispheres ◽  
Content Type ◽  
Subarachnoid Bleeding ◽  
Middle Cerebral Arteries ◽  
Before And After ◽  
The Mean ◽  
The Right ◽  
Subarachnoid Blood

✓ Bilateral measurements of regional cortical blood flow (CBF) and the diameter of superficial cortical arteries were made before and after puncture of the right middle cerebral arteries (MCA) of 11 cats with bilateral craniectomies. The CBF was decreased in the right cerebral hemispheres before puncture, probably because of manipulation and exposure of the MCA. Decreases of CBF occurred after MCA puncture in the contralateral cerebral hemispheres of five of seven animals without subarachnoid blood over the convexities of the hemispheres. The mean CBF value for the contralateral hemispheres was significantly lower after puncture than before. There was no consistent relationship between CBF and the calibers of surface cortical arteries. Thus, basal subarachnoid bleeding can cause decreases of CBF of the cerebral hemispheres, probably because of basal arterial spasm associated, at times, with vasomotor paralysis and failure of autoregulatory responses. If combined with increases of intracranial pressure, such decreases of CBF may be adequate to produce cerebral ischemia.

Effect of acute hemorrhage on the calculated lung hematocrit

1964 ◽  
Vol 206 (3) ◽  
pp. 557-561
Author(s):  
Robert H. Eich ◽  
Harold Smulyan ◽  
William A. Vincent ◽  
Frank W. Furth
Keyword(s):  
Blood Pressure ◽  
Indicator Dilution ◽  
Dilution Technique ◽  
Acute Hemorrhage ◽  
Reproducibility Study ◽  
Significant Difference ◽  
Before And After ◽  
The Mean ◽  
Mean Circulation ◽  
Control State

The hematocrit for the lesser circulation was determined in 22 dogs using Cr51-tagged cells and either indocyanine green or radioactive serum albumin as the plasma tag. To assess the variation due to methodology, a reproducibility study alone was done in 8 dogs, and in 14 dogs measurements were made before and after the blood pressure was lowered to 50 mm Hg by acute hemorrhage. The lung hematocrit was obtained both from the cell and plasma volume measured by the indicator dilution technique and by the ratio of the mean circulation times. There was no significant difference between the calculated lung hematocrit and the peripheral hematocrit in the control state or following hemorrhage.

Perbedaan Pengetahuan Siswa Tentang Penyakit Hepatitis A Sebelum Dan Sesudah Penyuluhan Di MTsN 02 Bondowoso Tahun 2015

2017 ◽  
Vol 4 (2) ◽  
pp. 14
Author(s):  
Putri Megasari
Keyword(s):  
Hepatitis A ◽  
Hepatitis Virus ◽  
Sampling Technique ◽  
Mean Value ◽  
Test Design ◽  
The World ◽  
Before And After ◽  
Post Test ◽  
The Mean ◽  
Paired T Test

Hepatitis has become a health problem in the world. The hepatitis virus infected many people. According to the teacher of MTsN 02 Bondowoso more than 20 students have hepatitis A viral infection. The purpose of this research was to know the differences of students' knowledge about hepatitis A before and after counseling in MTsN 02 Bondowoso 2015. This study used pre-experimental (pre-post test design). This study used stratified random sampling technique, 127 students from 270 sample involved this research,and 143 students was excluded. We used questionnaires to collect data. The results showed that the mean value of the students 'knowledge about hepatitis A before counseling in MTsN 02 Bondowoso 2015 was 83.96 with the lowest value of 37.5 and the highest value was 100. The mean value of the students' knowledge about hepatitis A after counseling in MTsN 02 Bondowoso 2015 was 93.21 with the lowest value waf 62.5 and the highest value was 100. Paired t test showed that t (-9.07) > t table (1.98), the null hypothesis (H0) was rejected. There was a difference between students' knowledge about hepatitis A before and after counseling in MTsN 02 Bondowoso 2015. This study showed that routine counseling by healthcare provider was important to prevent hepatitis A infection.; Keywords: counseling, knowledge of students, hepatitis

Quality of Life for Children with Persistent Sinonasal Symptoms

2003 ◽  
Vol 128 (1) ◽  
pp. 17-26 ◽  
Author(s):  
David J. Kay ◽  
Richard M. Rosenfeld
Keyword(s):  
Quality Of Life ◽  
Clinical Care ◽  
Longitudinal Change ◽  
Good Test ◽  
Routine Clinical Care ◽  
Before And After ◽  
The Mean ◽  
The Individual ◽  
Sinonasal Symptoms

OBJECTIVE: The goal was to validate the SN-5 survey as a measure of longitudinal change in health-related quality of life (HRQoL) for children with persistent sinonasal symptoms. DESIGN AND SETTING: We conducted a before and after study of 85 children aged 2 to 12 years in a metropolitan pediatric otolaryngology practice. Caregivers completed the SN-5 survey at entry and at least 4 weeks later. The survey included 5 symptom-cluster items covering the domains of sinus infection, nasal obstruction, allergy symptoms, emotional distress, and activity limitations. RESULTS: Good test-retest reliability ( R = 0.70) was obtained for the overall SN-5 score and the individual survey items ( R ≥ 0.58). The mean baseline SN-5 score was 3.8 (SD, 1.0) of a maximum of 7.0, with higher scores indicating poorer HRQoL. All SN-5 items had adequate correlation ( R ≥ 0.36) with external constructs. The mean change in SN-5 score after routine clinical care was 0.88 (SD, 1.19) with an effect size of 0.74 indicating good responsiveness to longitudinal change. The change scores correlated appropriately with changes in related external constructs ( R ≥ 0.42). CONCLUSIONS: The SN-5 is a valid, reliable, and responsive measure of HRQoL for children with persistent sinonasal symptoms, suitable for use in outcomes studies and routine clinical care.

scholarly journals Evaluation of pharmacy-led weight management service to minimise the risk of cardiovascular disease

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Aliki Peletidi ◽  
Reem Kayyali
Keyword(s):  
Physical Activity ◽  
Weight Management ◽  
Activity Levels ◽  
Management Service ◽  
Initial Weight ◽  
Public Health Services ◽  
Clinical Role ◽  
Physical Activity Levels ◽  
Before And After ◽  
The Mean

Abstract Aims The primary aim of the programme was a minimum of a 5% weight reduction of the initial weight, while the secondary outcomes were a reduction in participants’ body mass index (BMI), waist circumference (WC), blood pressure (BP), AUDIT-C score and an increase in the Mediterranean diet (MD) score and an improvement in physical activity levels. Methods This 'before and after' study was a 10-week weight management (WM) programme and it was developed and delivered in community pharmacies in Patras chosen for convenience, thus consisting the first service of its type in Greece. The sample size was calculated (n = 96) based on the mean BMI for a Greek male and female individual, and the standard deviation (SD) of weight at baseline of 14 kg. Results Nearly every participant enrolled in the 20 participating pharmacies, 97.4% (n = 114/117), achieved the programme’s aim, losing at least 5% of their initial weight. The mean percentage of total weight loss of the 117 participants at the 10th week was 8.97% (SD 2.65), and the t-test showed statistically significant results (P-value < 0.001; 95% CI [8.48, 9.45]). A significant reduction in the waist-to-height ratio (WHtR) was observed in both male (P-value = 0.004) and female (P-value < 0.001) participants. The participants’ BP and AUDIT-C score and physical activity levels significantly improved (P-value < 0.001), as well as their MD score. Conclusion This study provides the first evidence that Greek pharmacists have the potential to play an important role within primary healthcare and that after training they are able to provide public health services for both the public’s benefit and their clinical role enhancement.

scholarly journals CT perfusion in peripheral arterial disease—hemodynamic differences before and after revascularisation

2021 ◽  
Author(s):  
Patrick Veit-Haibach ◽  
Martin W. Huellner ◽  
Martin Banyai ◽  
Sebastian Mafeld ◽  
Johannes Heverhagen ◽  
...  
Keyword(s):  
Peripheral Arterial Disease ◽  
Ct Perfusion ◽  
Arterial Disease ◽  
Lower Leg ◽  
Therapy Control ◽  
Non Invasive ◽  
Before And After ◽  
Invasive Method ◽  
The Mean ◽  
Peripheral Arterial

Abstract Objectives The purpose of this study was the assessment of volumetric CT perfusion (CTP) of the lower leg musculature in patients with symptomatic peripheral arterial disease (PAD) before and after interventional revascularisation. Methods Twenty-nine consecutive patients with symptomatic PAD of the lower extremities requiring interventional revascularisation were assessed prospectively. All patients underwent a CTP scan of the lower leg, and hemodynamic and angiographic assessment, before and after intervention. Ankle-brachial pressure index (ABI) was determined. CTP parameters were calculated with a perfusion software, acting on a no outflow assumption. A sequential two-compartment model was used. Differences in CTP parameters were assessed with non-parametric tests. Results The cohort consisted of 24 subjects with an occlusion, and five with a high-grade stenosis. The mean blood flow before/after (BFpre and BFpost, respectively) was 7.42 ± 2.66 and 10.95 ± 6.64 ml/100 ml*min−1. The mean blood volume before/after (BVpre and BVpost, respectively) was 0.71 ± 0.35 and 1.25 ± 1.07 ml/100 ml. BFpost and BVpost were significantly higher than BFpre and BVpre in the treated limb (p = 0.003 and 0.02, respectively), but not in the untreated limb (p = 0.641 and 0.719, respectively). Conclusions CTP seems feasible for assessing hemodynamic differences in calf muscles before and after revascularisation in patients with symptomatic PAD. We could show that CTP parameters BF and BV are significantly increased after revascularisation of the symptomatic limb. In the future, this quantitative method might serve as a non-invasive method for surveillance and therapy control of patients with peripheral arterial disease. Key Points • CTP imaging of the lower limb in patients with symptomatic PAD seems feasible for assessing hemodynamic differences before and after revascularisation in PAD patients. • This quantitative method might serve as a non-invasive method, for surveillance and therapy control of patients with PAD.

scholarly journals Unilateral lateral rectus recession is an effective surgery for intermittent exotropia in young children

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Oriel Spierer ◽  
Abraham Spierer
Keyword(s):  
Young Children ◽  
Success Rate ◽  
Lateral Rectus ◽  
Intermittent Exotropia ◽  
Age At Surgery ◽  
Surgical Methods ◽  
Before And After ◽  
The Mean ◽  
Consecutive Esotropia

Abstract Background Different surgical methods have been suggested for the correction of intermittent exotropia. Unilateral lateral rectus recession has been described as a surgical alternative for small and moderate-angle exotropia. In general, previous studies did not focus on the outcomes of unilateral lateral rectus recession in young children with intermittent exotropia. The purpose of this study is to evaluate the surgical outcomes of unilateral lateral rectus recession in the treatment of moderate-angle exotropia (≤ 25 PD (prism diopters)) in children. Methods The charts of all patients younger than 12 years of age with moderate-angle exotropia (up to 25 PD) who were operated during the years 2006–2018 were retrospectively reviewed. Fifty-eight patients underwent unilateral lateral rectus recession and had a minimum follow up of 6 months. The angle of exotropia (PD) before and after surgery and the success rate were documented. Results Mean age at surgery was 6.4 ± 1.9 (range 3.5–11.0) years. Exotropia improved from a preoperative angle of 21.4 ± 4.0 PD to 3.5 ± 5.9 PD postoperatively (p < 0.001). Success rate, defined as deviation of ≤ 10 PD, was achieved in 86.2%. There were 2 (3.4%) cases of overcorrection (consecutive esotropia). There were no intra- or postoperative complications. The mean follow-up duration after surgery was 2.3 ± 1.7 years. Conclusions In children with moderate angle exotropia, good postoperative success rate was achieved by performing unilateral lateral rectus recession.

Evaluation of Changes in Depression Levels of Bruxism Patients Treated With Botulinum Toxin-A

2021 ◽  
pp. 232020682110065
Author(s):  
Deniz Erdil ◽  
Nilsun Bagis ◽  
Hakan Eren ◽  
Melike Camgoz ◽  
Kaan Orhan
Keyword(s):  
Botulinum Toxin ◽  
Botulinum Toxin A ◽  
Age Groups ◽  
Treatment Method ◽  
Definitive Treatment ◽  
Toxin A ◽  
Physiological Factors ◽  
Before And After ◽  
The Mean ◽  
Post Hoc

Aim: Bruxism is defined as the involuntary recurrent masticatory muscle activity characterized by gnashing, grinding, clenching of teeth, and/or pushing the mandible. Factors creating its etiology are peripheral (morphological) or central (physiopathological and physiological), and exogenous. Recently, among physiological factors, depression and bruxism were considered to be related. A definitive treatment method does not exist for bruxism; however, botulinum toxin-A (BT-A) application is an up-to-date and effective way of treatment. The present study is aimed to evaluate the levels of depression in bruxism patients treated with BT-A application. Materials and Methods: A total of 25 individuals (23 females and 2 males) who were diagnosed as bruxism patients were included in the study. 25 U of BT-A for each masseter muscle was injected into the patients. Patients were prospectively observed for a possible change in depression levels by using Beck’s Depression Inventory. The inventory was implemented before and six months after the BT-A application. Depression levels before and six months after the injection were compared. A paired t-test was used to compare “before” and “after” treatment values. One-way analysis of variance and post-hoc Tukey tests were used to evaluate the change in Beck’s Depression Inventory scores according to age groups. Results: The mean total score was 7.80 ± 8.10 before the treatment and 7.16 ± 6.52 six months after the treatment. The decrease in the mean score was not statistically significant ( P > .05). Conclusion: In conclusion, despite the decrease in the mean Beck’s Depression Inventory scores, a statistically significant decrease in the depression levels of patients was not observed.

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