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Sample records for ocular arterial flow

  1. Relationship between the Direction of Ophthalmic Artery Blood Flow and Ocular Microcirculation before and after Carotid Artery Stenting.

    Ishii, Masashi; Hayashi, Morito; Yagi, Fumihiko; Sato, Kenichiro; Tomita, Goji; Iwabuchi, Satoshi

    2016-01-01

    When internal carotid artery stenosis is accompanied by ocular ischemic syndrome, intervention is recommended to prevent irreversible visual loss. In this study, we used laser speckle flowgraphy to measure the ocular microcirculation in the optic nerve head before and after carotid artery stenting (CAS) of 40 advanced internal carotid stenosis lesions from 37 patients. The aim was to investigate the relationship between ocular microcirculation and the direction of ophthalmic artery blood flow obtained by angiography. We found that there was a significant increase in blood flow after CAS ( P = 0.003). Peak systolic velocity as an indicator of the rate of stenosis was also significantly higher in the group with retrograde/undetected flow of the ophthalmic artery than in the group with antegrade flow ( P = 0.002). In all cases where retrograde flow of the ophthalmic artery was observed before stenting, the flow changed to antegrade after stenting. Through the use of laser speckle flowgraphy, this study found that CAS can improve ocular microcirculation. Furthermore, while patients displaying retrograde flow of the ophthalmic artery before stenting have a poor prognosis, CAS corrected the flow to antegrade, suggesting that visual loss can be prevented by improving the ocular microcirculation.

  2. Evaluating ocular blood flow

    Jyotsna Maram

    2017-01-01

    Full Text Available Studies have shown that vascular impairment plays an important role in the etiology and pathogenesis of various ocular diseases including glaucoma, age-related macular degeneration, diabetic retinopathy, and retinal venous occlusive disease. Thus, qualitative and quantitative assessment of ocular blood flow (BF is a topic of interest for early disease detection, diagnosis, and management. Owing to the rapid improvement in technology, there are several invasive and noninvasive techniques available for evaluating ocular BF, with each of these techniques having their own limitations and advantages. This article reviews these important techniques, with a particular focus on Doppler Fourier domain optical coherence tomography (OCT and OCT-angiography.

  3. Color Doppler evaluation of the ocular arterial flow changes in chronic obstructive pulmonary disease

    Ozer, Tulay; Altin, Remzi; Ugurbas, Suat Hayri; Ozer, Yetkin; Mahmutyazicioglu, Kamran; Kart, Levent

    2006-01-01

    Purpose: To evaluate the hemodynamic changes in the extraocular orbital vessels of the patients with chronic obstructive pulmonary disease (COPD), using color Doppler ultrasonography (CDU) technique, and to compare the results with those of healthy control subjects. Methods: Forty-five patients with COPD and 17 healthy control subjects were included in this study. Patients with COPD were classified according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD). Fifteen patients of stage I COPD (mild airflow limitation), stage II COPD (worsening airflow limitation) or stage III COPD (severe airflow limitation) were enrolled into Group I, II and III, respectively. End tidal carbon dioxide (EtCO 2 ), peripheral oxygen saturation (SpO 2 ), pulse rate (PR) and respiratory rate (RR) were measured by using capnograph/pulse oximeter in all patients. Measurements were performed in only one randomly chosen eye of each participant. The peak systolic velocity (PSV), end-diastolic velocity (EDV), and resistance index (RI) were measured in the ophthalmic artery (OA), central retinal artery (CRA), lateral short posterior ciliary artery (LPCA) and medial short posterior ciliary artery (MPCA), using CDU technique. Results: The PSV measurements of the OA were significantly higher in Groups II and III compared to control group (p 2 with PSV (r = 0.53, p < 0.01) and EDV (r = 0.51, p < 0.01) of the OA. Statistically significant correlations were also found for the SpO2 with RI (r = -0.34, p < 0.05) in the OA. Conclusion: We concluded that COPD is associated with impaired retrobulbar hemodynamics, especially in the ophthalmic artery. Moreover, central retinal and posterior ciliary arteries with increased resistance are also found to be affected when compared with healthy control eyes

  4. Ocular Perfusion Pressure and Pulsatile Ocular Blood Flow in Normal and Systemic Hypertensive Patients.

    Kanadani, Fabio N; Figueiredo, Carlos R; Miranda, Rafaela Morais; Cunha, Patricia Lt; M Kanadani, Tereza Cristina; Dorairaj, Syril

    2015-01-01

    Glaucomatous neuropathy can be a consequence of insufficient blood supply, increase in intraocular pressure (IOP), or other risk factors that diminish the ocular blood flow. To determine the ocular perfusion pressure (OPP) in normal and systemic hypertensive patients. One hundred and twenty-one patients were enrolled in this prospective and comparative study and underwent a complete ophthalmologic examination including slit lamp examination, Goldmann applanation tonometry, stereoscopic fundus examination, and pulsatile ocular blood flow (POBF) measurements. The OPP was calculated as being the medium systemic arterial pressure (MAP) less the IOP. Only right eye values were considered for calculations using Student's t-test. The mean age of the patients was 57.5 years (36-78), and 68.5% were women. There was a statistically significant difference in the OPP of the normal and systemic hypertensive patients (p cite this article: Kanadani FN, Figueiredo CR, Miranda RM, Cunha PLT, Kanadani TCM, Dorairaj S. Ocular Perfusion Pressure and Pulsatile Ocular Blood Flow in Normal and Systemic Hypertensive Patients. J Curr Glaucoma Pract 2015;9(1):16-19.

  5. Ocular Blood Flow and Normal Tension Glaucoma

    Ning Fan

    2015-01-01

    Full Text Available Normal tension glaucoma (NTG is known as a multifactorial optic neuropathy characterized by progressive retinal ganglion cell death and glaucomatous visual field loss, even though the intraocular pressure (IOP does not exceed the normal range. The pathophysiology of NTG remains largely undetermined. It is hypothesized that the abnormal ocular blood flow is involved in the pathogenesis of this disease. A number of evidences suggested that the vascular factors played a significant role in the development of NTG. In recent years, the new imaging techniques, fluorescein angiography, color Doppler imaging (CDI, magnetic resonance imaging (MRI, and laser speckle flowgraphy (LSFG, have been used to evaluate the ocular blood flow and blood vessels, and the impaired vascular autoregulation was found in patients with NTG. Previous studies showed that NTG was associated with a variety of systemic diseases, including migraine, Alzheimer’s disease, primary vascular dysregulation, and Flammer syndrome. The vascular factors were involved in these diseases. The mechanisms underlying the abnormal ocular blood flow in NTG are still not clear, but the risk factors for glaucomatous optic neuropathy likely included oxidative stress, vasospasm, and endothelial dysfunction.

  6. Inner ocular blood flow responses to an acute decrease in blood pressure in resting humans

    Ikemura, Tsukasa; Kashima, Hideaki; Yamaguchi, Yuji; Miyaji, Akane; Hayashi, Naoyuki

    2015-01-01

    Whether inner ocular vessels have an autoregulatory response to acute fluctuations in blood pressure is unclear. We tried to examine the validity of acute hypotension elicited by thigh-cuff release as to assess the dynamic autoregulation in the ocular circulation. Blood flow velocity in the superior nasal and inferior temporal retinal arterioles, and in the retinal and choroidal vasculature were measured with the aid of laser speckle flowgraphy before and immediately after an acute decrease in blood pressure in 20 healthy subjects. Acute hypotension was induced by a rapid release of bilateral thigh occlusion cuffs that had been inflated to 220 mmHg for 2 min. The ratio of the relative change in retinal and choroidal blood flow velocity to the relative change in mean arterial blood pressure (MAP) was calculated. Immediately after cuff release, the MAP and blood flows in the all ocular target vessels decreased significantly from the baseline values obtained before thigh-cuff release. The ratio of the relative change in inner ocular blood flow velocity to that in the MAP exceeded 1% / %mmHg. An explicit dynamic autoregulation in inner ocular vessels cannot be demonstrated in response to an acute hypotension induced by the thigh-cuff release technique. (paper)

  7. Ocular blood flow decreases during passive heat stress in resting humans.

    Ikemura, Tsukasa; Miyaji, Akane; Kashima, Hideaki; Yamaguchi, Yuji; Hayashi, Naoyuki

    2013-12-06

    Heat stress induces various physiological changes and so could influence ocular circulation. This study examined the effect of heat stress on ocular blood flow. Ocular blood flow, end-tidal carbon dioxide (P(ET)CO2) and blood pressure were measured for 12 healthy subjects wearing water-perfused tube-lined suits under two conditions of water circulation: (1) at 35 °C (normothermia) for 30 min and (2) at 50 °C for 90 min (passive heat stress). The blood-flow velocities in the superior temporal retinal arteriole (STRA), superior nasal retinal arteriole (SNRA), and the retinal and choroidal vessels (RCV) were measured using laser-speckle flowgraphy. Blood flow in the STRA and SNRA was calculated from the integral of a cross-sectional map of blood velocity. PETCO2 was clamped at the normothermia level by adding 5% CO2 to the inspired gas. Passive heat stress had no effect on the subjects' blood pressures. The blood-flow velocity in the RCV was significantly lower after 30, 60 and 90 min of passive heat stress than the normothermic level, with a peak decrease of 18 ± 3% (mean ± SE) at 90 min. Blood flow in the STRA and SNRA decreased significantly after 90 min of passive heat stress conditions, with peak decreases of 14 ± 3% and 14 ± 4%, respectively. The findings of this study suggest that passive heat stress decreases ocular blood flow irrespective of the blood pressure or arterial partial pressure of CO2.

  8. Effect of tropicamide on ocular blood flow in the rabbit

    Delgado, D.; Michel, P.; Jaanus, S.D.

    1982-01-01

    Intracardiac injection of 15 microspheres labeled with 85 Sr (strontium) and 141 Ce (cerium) were used to determine ocular blood flow in seven rabbits before and 25 min after bilateral application of tropicamide to the cornea. By using two different isotopes distinguishable under gammaspectrometry, each animal served as its own control. After administration of two drops of 1% tropicamide, no significant difference in blood flow between treated and untreated eyes was observed

  9. Glaucoma patients demonstrate faulty autoregulation of ocular blood flow during posture change

    Evans, D.; Harris, A.; Garrett, M.; Chung, H. S.; Kagemann, L.

    1999-01-01

    BACKGROUND/AIMS—Autoregulation of blood flow during posture change is important to ensure consistent organ circulation. The purpose of this study was to compare the change in retrobulbar ocular blood flow in glaucoma patients with normal subjects during supine and upright posture.
METHODS—20 open angle glaucoma patients and 20 normal subjects, similar in age and sex distribution, were evaluated. Blood pressure, intraocular pressure, and retrobulbar blood velocity were tested after 30 minutes of sitting and again after 30 minutes of lying. Retrobulbar haemodynamic measures of peak systolic velocity (PSV), end diastolic velocity (EDV), and resistance index (RI) were obtained in the ophthalmic and central retinal arteries using colour Doppler imaging (CDI).
RESULTS—When changing from the upright to supine posture, normal subjects demonstrated a significant increase in OA EDV (p = 0.016) and significant decrease in OA RI (p = 0.0006) and CRA RI (p = 0.016). Glaucoma patients demonstrated similar changes in OA measures of EDV (p = 0.02) and RI (p = 0.04), but no change in CRA measures.
CONCLUSION—Glaucoma patients exhibit faulty autoregulation of central retinal artery blood flow during posture change.

 PMID:10381668

  10. Arterial secondary blood flow patterns visualized with vector flow ultrasound

    Pedersen, Mads Møller; Pihl, Michael Johannes; Hansen, Jens Munk

    2011-01-01

    This study presents the first quantification and visualisation of secondary flow patterns with vector flow ultrasound. The first commercial implementation of the vector flow method Transverse Oscillation was used to obtain in-vivo, 2D vector fields in real-time. The hypothesis of this study...... was that the rotational direction is constant within each artery. Three data sets of 10 seconds were obtained from three main arteries in healthy volunteers. For each data set the rotational flow patterns were identified during the diastole. Each data set contains a 2D vector field over time and with the vector angles...

  11. Ocular blood flow decreases during passive heat stress in resting humans

    Ikemura, Tsukasa; Miyaji, Akane; Kashima, Hideaki; Yamaguchi, Yuji; Hayashi, Naoyuki

    2013-01-01

    Background Heat stress induces various physiological changes and so could influence ocular circulation. This study examined the effect of heat stress on ocular blood flow. Findings Ocular blood flow, end-tidal carbon dioxide (P ETCO2) and blood pressure were measured for 12 healthy subjects wearing water-perfused tube-lined suits under two conditions of water circulation: (1) at 35°C (normothermia) for 30 min and (2) at 50°C for 90 min (passive heat stress). The blood-flow velocities in the s...

  12. Modern Diagnostic Techniques for the Assessment of Ocular Blood Flow in Myopia: Current State of Knowledge.

    Grudzińska, Ewa; Modrzejewska, Monika

    2018-01-01

    Myopia is the most common refractive error and the subject of interest of various studies assessing ocular blood flow. Increasing refractive error and axial elongation of the eye result in the stretching and thinning of the scleral, choroid, and retinal tissues and the decrease in retinal vessel diameter, disturbing ocular blood flow. Local and systemic factors known to change ocular blood flow include glaucoma, medications and fluctuations in intraocular pressure, and metabolic parameters. Techniques and tools assessing ocular blood flow include, among others, laser Doppler flowmetry (LDF), retinal function imager (RFI), laser speckle contrast imaging (LSCI), magnetic resonance imaging (MRI), optical coherence tomography angiography (OCTA), pulsatile ocular blood flowmeter (POBF), fundus pulsation amplitude (FPA), colour Doppler imaging (CDI), and Doppler optical coherence tomography (DOCT). Many researchers consistently reported lower blood flow parameters in myopic eyes regardless of the used diagnostic method. It is unclear whether this is a primary change that causes secondary thinning of ocular tissues or quite the opposite; that is, the mechanical stretching of the eye wall reduces its thickness and causes a secondary lower demand of tissues for oxygen. This paper presents a review of studies assessing ocular blood flow in myopes.

  13. Ocular Image and Haemodynamic Features Associated with Different Gradings of Ipsilateral Internal Carotid Artery Stenosis

    Hui Wang

    2017-01-01

    Full Text Available Objectives. To analyse the changes of ocular haemodynamics and morphology in Chinese patients with internal carotid artery (ICA stenosis in the current study. Methods. A retrospective case-control study was conducted with 219 patients. The haemodynamic characteristics, the calibre of retinal vessels, and the subfoveal choroidal thickness (SFChT were compared. We analysed the correlations with the degree of ipsilateral ICA stenosis. Results. There were no significant differences among the groups in the central retinal artery equivalent (CRAE, central retinal vein equivalent (CRVE, and AVR (p=0.073, p=0.188, and p=0.738, resp.. The peak systolic velocity (PSV and end diastolic velocity (EDV in the central retinal artery (CRA and the posterior ciliary artery (PCA were significantly lower than normal eyes (p<0.001. The outer retinal layer thickness and SFChT values of the ICA stenosis groups were significantly lower than normal eyes (p=0.030 and p<0.001, resp.. Conclusion. The PSV and EDV in CRA and PCA and the SFChT and outer retinal layer thickness of ICA eyes were significantly lower than normal eyes. ICA stenosis may impact choroidal haemodynamics, and decreased choroidal circulation might affect the discordance of the SFChT and the outer retinal layer thickness.

  14. CORRELATION BETWEEN UTERINE ARTERY FLOW VELOCITY ...

    CORRELATION BETWEEN UTERINE ARTERY FLOW VELOCITY WAVEFORMS AND ENDOMETRIAL HISTOPATHOLOGY IN WOMEN WITH PERIMENOPAUSAL AND POSTMENOPAUSAL BLEEDING. Dr. Ebtesam Saied, Dr. Ismail El Garhy(MD), Dr. Farid I. Hassan(MD), Dr. Adel-Gamil Abd-Allah, Abd El Shafy Ibrahim ...

  15. Ocular neovascularization in eyes with a central retinal artery occlusion or a branch retinal artery occlusion

    Mason lll JO

    2015-06-01

    Full Text Available John O Mason III,1,2 Shyam A Patel,1 Richard M Feist,1,2 Michael A Albert Jr,1,2 Carrie Huisingh,1 Gerald McGwin Jr,1,3 Martin L Thomley1,2 1Department of Ophthalmology, University of Alabama School of Medicine, Birmingham, AL, USA; 2Retina Consultants of Alabama, Callahan Eye Foundation Hospital, Birmingham, AL, USA; 3Department of Epidemiology, School of Public Health, University of Alabama at Birmingham, Birmingham, AL, USA Purpose: To investigate the ocular neovascularization (ONV rate in eyes with a branch retinal artery occlusion (BRAO or a central retinal artery occlusion (CRAO, and to study factors that may influence the ONV rate secondary to CRAO.Methods: This was a retrospective case series of consecutive patients (286 total eyes: 83 CRAOs and 203 BRAOs who were diagnosed with a retinal artery occlusion from 1998 to 2013 at the Retina Consultants of Alabama and University of Alabama at Birmingham, Birmingham, AL, USA. Generalized estimating equations were used to evaluate the association between hypothesized risk factors and ONV development.Results: Twelve (14.5% of the 83 eyes with a CRAO developed ONV. Eleven of 12 eyes (91.7% had iris neovascularization, ten of 12 eyes (83.3% had neovascular glaucoma, and two of 12 eyes (16.7% had neovascularization of the optic disc. The average time for ONV development secondary to CRAO was 30.7 days, ranging from the date of presentation to 137 days. Only two (<1.0% of the 203 eyes with a BRAO developed iris neovascularization. Diabetes mellitus type 2 was a risk factor for ONV development following a CRAO with an adjusted odds ratio of 5.2 (95% confidence interval: 1.4–19.8 (P=0.02.Conclusion: ONV is an important complication of CRAO and is a less-frequent complication of BRAO. Patients with a CRAO, especially those with diabetes mellitus type 2, should be closely monitored for the first 6 months for ONV. Keywords: neovascularization, neovascular glaucoma, retinal artery occlusion, central

  16. Pulsatile spiral blood flow through arterial stenosis.

    Linge, Fabian; Hye, Md Abdul; Paul, Manosh C

    2014-11-01

    Pulsatile spiral blood flow in a modelled three-dimensional arterial stenosis, with a 75% cross-sectional area reduction, is investigated by using numerical fluid dynamics. Two-equation k-ω model is used for the simulation of the transitional flow with Reynolds numbers 500 and 1000. It is found that the spiral component increases the static pressure in the vessel during the deceleration phase of the flow pulse. In addition, the spiral component reduces the turbulence intensity and wall shear stress found in the post-stenosis region of the vessel in the early stages of the flow pulse. Hence, the findings agree with the results of Stonebridge et al. (2004). In addition, the results of the effects of a spiral component on time-varying flow are presented and discussed along with the relevant pathological issues.

  17. Left coronary arterial blood flow: Noninvasive detection by Doppler US

    Gramiak, R.; Holen, J.; Moss, A.J.; Gutierrez, O.H.; Picone, A.L.; Roe, S.A.

    1986-01-01

    Continuous wave (CW) and pulsed Doppler ultrasound studies with spectral analysis were used to detect the left coronary arterial blood flow in patients who were undergoing routine echocardiography. The pulmonary artery is a stable ultrasonic landmark from which detection of the blood flow can be effected. The left coronary artery can be distinguished by its blood flow toward the cardiac apex and by specific, functional flow features. Flow patterns vary among the left main, circumflex, and anterior descending arteries; patterns also vary with respiration cycles. In the present study, coronary arterial blood flow was detected in 58 of 70 patients (83%). Findings were validated by selectively injecting an agitated saline contrast medium into the left coronary artery and, in another study, by comparing human Doppler phasic flow waveforms with electromagnetic flowmeter recordings obtained in dogs

  18. Retinal protective effects of topically administered agmatine on ischemic ocular injury caused by transient occlusion of the ophthalmic artery

    S. Hong

    2012-03-01

    Full Text Available Agmatine, an endogenous polyamine and putative neuromodulator, is known to have neuroprotective effects on various neurons in the central nervous system. We determined whether or not topically administered agmatine could reduce ischemic retinal injury. Transient ocular ischemia was achieved by intraluminal occlusion of the middle cerebral artery of ddY mice (30-35 g for 2 h, which is known to also induce occlusion of the ophthalmic artery. In the agmatine group (N = 6, a 1.0 mM agmatine-containing ophthalmic solution was administered four times daily for 2 weeks before occlusion. In the control group (N = 6, a 0.1% hyaluronic acid ophthalmic solution was instilled at the same times. At 22 h after reperfusion, the eyeballs were enucleated and the retinal sections were stained by terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL. Transient ocular ischemia induced apoptosis of retinal cells in the entire retinal layer, and topically administered agmatine can significantly reduce this ischemic retinal injury. The proportion of apoptotic cells was definitely decreased (P < 0.001; Kruskal-Wallis test. Overall, we determined that topical agmatine application effectively decreases retinal damage in an in vivo ocular ischemic injury model. This implies that agmatine is a good candidate as a direct neuroprotective agent for eyes with ocular ischemic diseases.

  19. Retinal protective effects of topically administered agmatine on ischemic ocular injury caused by transient occlusion of the ophthalmic artery

    Hong, S.; Hara, H.; Shimazawa, M.; Hyakkoku, K.; Kim, C.Y.; Seong, G.J.

    2012-01-01

    Agmatine, an endogenous polyamine and putative neuromodulator, is known to have neuroprotective effects on various neurons in the central nervous system. We determined whether or not topically administered agmatine could reduce ischemic retinal injury. Transient ocular ischemia was achieved by intraluminal occlusion of the middle cerebral artery of ddY mice (30-35 g) for 2 h, which is known to also induce occlusion of the ophthalmic artery. In the agmatine group (N = 6), a 1.0 mM agmatine-containing ophthalmic solution was administered four times daily for 2 weeks before occlusion. In the control group (N = 6), a 0.1% hyaluronic acid ophthalmic solution was instilled at the same times. At 22 h after reperfusion, the eyeballs were enucleated and the retinal sections were stained by terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL). Transient ocular ischemia induced apoptosis of retinal cells in the entire retinal layer, and topically administered agmatine can significantly reduce this ischemic retinal injury. The proportion of apoptotic cells was definitely decreased (P agmatine application effectively decreases retinal damage in an in vivo ocular ischemic injury model. This implies that agmatine is a good candidate as a direct neuroprotective agent for eyes with ocular ischemic diseases. PMID:22331138

  20. Evaluation of ocular acupuncture on cerebral infarction with cerebral blood flow perfusion imaging

    Li Yuge; Gao Qinyi; Wang Shuang; Zhao Yong

    2008-01-01

    To evaluate the immediate effect of ocular acupuncture on patients, an method of SPECT image of cerebral blood flow daily stress test was established. 10 patients diagnosed as cerebral infarction by CT or MRI were tested. They all received 99 Tc m -ECD SPECT imaging at twice before and after ocular acupuncture. By means of image subtraction technique and semi-quantitative method of regional interesting area, the change of regional cerebral blood flow was observed between the two images. Under restful state perfusion of cerebral blood flow in 18 foci was low at the frontal lobe, the cerebellum, the basal ganglia and temporal lobe. After ocular acupuncture, the perfusions were obviously increased in 16 foci among them and the reactivity of the frontal lobe and the cerebellum to ocular acupuncture was higher, the average improvement rate of which was 55.15% and 53.06% respectively, lower in the basal ganglia and temporal lobe, the average improvement rate was 31.79% and 36.67% respectively. 99 Tc m -ECD SPECT cerebral perfusion image has some significant clinic value for evaluating the effect of ocular acupuncture to treating cerebral infarction. (authors)

  1. Prediction of coronary artery bypass graft flow

    Tamiya, Eiji; Hada, Yoshiyuki; Asano, Ken-ichi; Iio, Masahiro.

    1991-01-01

    To predict the coronary artery bypass graft (CABG) flow based on the time density curve (TDC) obtained from the digital subtraction aortograms (DSA), we developed a pulsatile CABG model (perfusion pressure 60,130 mmHg, pulse rate 53,126/min, cardiac output 3-7 l/min, diameter of the graft 2.1∼6.0 mm). After positioning the regions of interest (ROI), we injected contrast medium(5∼40 ml/sec, 5∼40 ml) into the outlet conduit. Concerning the TDCs, we calculated appearance time (Ta), peak densities (Dp), peak time (Tp), disappearance time (Td), integral of TDC, ΔTp (difference of Tp between two ROI) and ΔTa (difference of Ta between two ROI). Perfusion pressure, graft flow and output curve were similar to those of patients with CABG. Ta, Tp, Td, and ΔTp were affected by both the injection rate and the volume of the contrast medium; while Dp and the TDC integral were only affected by the latter parameter. Under the same conditions of contrast medium injection, the TDC depended strongly on graft flow, diameter of the graft, output and pulse rate. 21.6+0.92π·d 2 /4·Δ1/ΔTp·60 provided the most accurate estimation of CABG flow (r=0.865, p<0.01). We conclude that densitometric analysis of DSA may be useful in the prediction of CABG flow. (author)

  2. Assessment of effect of intravitreal ranibizumab injection on the ocular blood flow in patients with neovascular age-related macular degeneration

    V. V. Neroev

    2014-07-01

    Full Text Available Purpose: To evaluate the effect of intravitreal ranibizumab injection on the ocular blood flow in patients with neovascular agerelatedmacular degeneration (AMD.Methods: 35 patients with wet AMD undergone intravitreal 0.5 mg ranibizumab injection. Color Doppler Imaging (CDI and dopplerographywere used to measure hemodynamic parameters including the peak systolic velocity (Vsyst, cm / s, end-diastolic velocity (V diast, cm / s, and resistance index (RI of blood flow in the central retinal artery (CRA, the short posterior ciliary arteries (PCA, and the ophthalmic artery (OA. All patients were examined before and after injection on day 1‑7 and 30 day during the 3‑month follow up period.Results: Before intravitreal injection Vsyst was decreased in short PCA (p<0.05, RI in CRA and in short PCA significantly increased in comparison with normal index in same vessels. The peak systolic velocity in OA, in CRA and in short PCA was not significantly changed. After second injection resistance index in CRA and in short PCA was normalized.Conclusion: There was not impairment of ocular blood flow in retinal and choroidal after monthly intravitreal injection of ranibizumab during the 3‑month follow up period.

  3. Assessment of effect of intravitreal ranibizumab injection on the ocular blood flow in patients with neovascular age-related macular degeneration

    V. V. Neroev

    2013-01-01

    Full Text Available Purpose: To evaluate the effect of intravitreal ranibizumab injection on the ocular blood flow in patients with neovascular agerelatedmacular degeneration (AMD.Methods: 35 patients with wet AMD undergone intravitreal 0.5 mg ranibizumab injection. Color Doppler Imaging (CDI and dopplerographywere used to measure hemodynamic parameters including the peak systolic velocity (Vsyst, cm / s, end-diastolic velocity (V diast, cm / s, and resistance index (RI of blood flow in the central retinal artery (CRA, the short posterior ciliary arteries (PCA, and the ophthalmic artery (OA. All patients were examined before and after injection on day 1‑7 and 30 day during the 3‑month follow up period.Results: Before intravitreal injection Vsyst was decreased in short PCA (p<0.05, RI in CRA and in short PCA significantly increased in comparison with normal index in same vessels. The peak systolic velocity in OA, in CRA and in short PCA was not significantly changed. After second injection resistance index in CRA and in short PCA was normalized.Conclusion: There was not impairment of ocular blood flow in retinal and choroidal after monthly intravitreal injection of ranibizumab during the 3‑month follow up period.

  4. Immersed boundary simulation of flow through arterial junctions

    Dwaipayan Sarkar

    haemodynamic activities in regions like carotid arteries, encephalic regions and ... immersed boundary method (IBM), has gained attention in the last few years .... the flow from left inlet and the flow is subsequently divided among the two ...

  5. Flow analysis of the ophthalmic artery

    Harada, Kuniaki; Hashimoto, Masato; Bandoh, Michio; Odawara, Yoshihiro; Kamagata, Masaki; Shirase, Ryuji [Sapporo Medical Univ. (Japan). Hospital

    2003-02-01

    The purpose of this study was to analyze the hemodynamics of ophthalmic artery flow using phase contrast MR angiography (PC-MRA). A total of 14 eyes from 10 normal volunteers and a patient with normal tension glaucoma (NTG) were analyzed. The optimal conditions were time repetition (TR)/echo time (TE)/flip angle (FA)/nex=40 ms/minimum/90 deg/2, field of view (FOV)=6 cm, matrix size=256 x 256. The resistive index (RI) and pulsatillity index (PI) values were significantly raised in the patient with NTG when compared to the control group. We therefore believe that PC-MRA may be a useful clinical tool for the assessment of the mechanism of NTG. (author)

  6. Forearm arterial anatomy and flow characteristics: a prospective observational study.

    Pancholy, Samir B; Heck, Laura A; Patel, Tejas

    2015-04-01

    Morphometric data on Caucasian radial and ulnar arteries are limited, with no data on flow interdependence in the forearm arterial circuit. A total of 250 upper extremities in 125 patients were evaluated. Ultrasonography was performed and radial and ulnar artery lumen diameters were measured. Ulnar artery (UA) was compressed at the level of the wrist, and flow parameters in radial artery (RA) were recorded using duplex Doppler ultrasound. Radial and ulnar artery diameters were comparable at the level of the distal forearm (RA = 2.03 ± 0.28 mm, UA = 2.07 ± 0.27 mm; P=.14). There was no significant difference in radial or ulnar artery diameter between the dominant upper extremity and the non-dominant upper extremity. Upon compression of the ulnar artery, radial artery velocity-time integral (VTI) increased from 8.4 ± 3.8 cm to 12.8 ± 5.5 cm, which was statistically significant (Pforearm is comparable to UA. RA-VTI and likely flow significantly increase by compression of the UA. The smaller the radial artery, the larger the increase in radial artery flow with ulnar compression.

  7. Dynamic exercise enhances regional cerebral artery mean flow velocity

    Linkis, P; Jørgensen, L G; Olesen, H L

    1995-01-01

    Dynamic exercise enhances regional cerebral artery mean flow velocity. J. Appl. Physiol. 78(1): 12-16, 1995.--Anterior (ACA) and middle (MCA) cerebral artery mean flow velocities (Vmean) and pulsatility indexes were determined using transcranial Doppler in 14 subjects during dynamic exercise afte...

  8. Ocular Blood Flow Measurements in Healthy White Subjects Using Laser Speckle Flowgraphy.

    Nikolaus Luft

    Full Text Available To assess the feasibility and reliability of Laser Speckle Flowgraphy (LSFG to measure ocular perfusion in a sample of healthy white subjects and to elucidate the age-dependence of the parameters obtained.This cross-sectional study included 80 eyes of 80 healthy, non-smoking white subjects of Western European descent between 19 and 79 years of age. A commercial LSFG instrument was applied to measure ocular blood flow at the optic nerve head (ONH three successive times before and after pharmacological pupil dilation. The mean blur rate (MBR, a measure of relative blood flow velocity, was obtained for different regions of the ONH. Eight parameters of ocular perfusion derived from the pulse-waveform analysis of MBR including blowout time (BOT and falling rate (FR were also recorded.Artifact-free LSFG images meeting the quality criteria for automated image analysis were obtainable in 93.8% without pupil dilation and in 98.8% with pharmacological pupil dilation. Measurements of MBR showed excellent repeatability with intraclass correlation coefficients ≥ 0.937 and were barely affected by pupil dilation. The majority of pulse-waveform derived variables exhibited equally high repeatability. MBR-related blood flow indices exhibited significant age dependence (p<0.001. FR (r = 0.747, p<0.001 and BOT (r = -0.714, p<0.001 most strongly correlated with age.LSFG represents a reliable method for the quantitative assessment of ocular blood flow in white subjects. Our data affirms that the LSFG-derived variables FR and BOT may be useful biomarkers for age-related changes in ocular perfusion.

  9. [Ultrasonographic study of blood flow in the renal arteries of patients with arterial hypertension].

    Makarenko, E S; Dombrovskiĭ, V I; Nelasov, N Iu

    2012-01-01

    Vascular duplex ultrasound duplex with simultaneous ECG registration was made to estimate the quantitative and time parameters of blood flow in the renal arteries with grade 1-2 arterial hypertension. There were increases in vascular resistance indices and acceleration phase index and a reduction in systolic phase index. There were correlations of the time parameters of blood flow in the renal arteries with age and lipidogram values.

  10. Decreased ocular blood flow after photocoagulation therapy in neonatal retinopathy of prematurity.

    Matsumoto, Tadashi; Itokawa, Takashi; Shiba, Tomoaki; Tomita, Masahiko; Hine, Kotaro; Mizukaki, Norio; Yoda, Hitoshi; Hori, Yuichi

    2017-11-01

    To evaluate the relationships between optic nerve head blood flow, expressed as mean blur rate (MBR) measured by laser speckle flowgraphy (LSFG), and photocoagulation therapy in neonates with retinopathy of prematurity (ROP). Case series study. We studied 5 ROP neonates either during sleep or under sedation both before and after photocoagulation, and evaluated 8 eyes in which the circulation could be measured three times consecutively. Correlations between the MBR-A (mean of all values), MBR-V (vessel mean) and MBR-T (tissue mean) and postmenstrual age were evaluated using Spearman's rank correlation coefficient. In addition, correlations between the relative MBR (-A, -V, -T) value and number of photocoagulation burns and the NV score were evaluated. Differences between post-treatment MBR in ROP subjects and normal neonates' MBR were estimated using analysis of covariance (ANCoVA), with adjustment for postmenstrual age. The relative MBR (-A, -V, -T) values after photocoagulation were 69.6 ± 16.0%, 66.7 ± 17.0% and 74.3 ± 14.6%, respectively. Postmenstrual age was significantly correlated with post-treatment MBR-A (r = 0.83, p = 0.0101), MBR-V (r = 0.85, p = 0.007) and MBR-T (r = 0.76, p = 0.0282). The relative MBR-T value was significantly correlated with the number of photocoagulation burns (r = -0.75, p = 0.033) and NV score (r = -0.72, p = 0.0437). The ANCoVA results showed no significant difference between post-treatment MBR and normal neonates' MBR. Photocoagulation improved the dilation of veins and tortuosity of arteries and reduced ocular blood flow in ROP subjects. Since the post-treatment MBR was not different from a normal neonate's MBR, it is suggested that the pre-treatment MBR was higher in severe ROP cases.

  11. Ocular Blood Flow Measured Noninvasively in Zero Gravity

    Ansari, Rafat R.; Manuel, Francis K.; Geiser, Martial; Moret, Fabrice; Messer, Russell K.; King, James F.; Suh, Kwang I.

    2003-01-01

    In spaceflight or a reduced-gravity environment, bodily fluids shift to the upper extremities of the body. The pressure inside the eye, or intraocular pressure, changes significantly. A significant number of astronauts report changes in visual acuity during orbital flight. To date this remains of unknown etiology. Could choroidal engorgement be the primary mechanism and a change in the curvature or shape of the cornea or lens be the secondary mechanism for this change in visual acuity? Perfused blood flow in the dense meshwork of capillaries of the choroidal tissue (see the preceding illustration) provides necessary nutrients to the outer layers of the retina (photoreceptors) to keep it healthy and maintain good vision. Unlike the vascular system, the choroid has no baroreceptors to autoregulate fluid shifts, so it can remain engorged, pushing the macula forward and causing a hyperopic (farsighted) shift of the eye. Experiments by researchers at the NASA Glenn Research Center could help answer this question and facilitate planning for long-duration missions. We are investigating the effects of zero gravity on the choroidal blood flow of volunteer subjects. This pilot project plans to determine if choroidal blood flow is autoregulated in a reduced-gravity environment.

  12. [Prognostic Doppler ultrasound examination of fetal arteries blood flow].

    Sieroszewski, Piotr; Sabatowska, Małgorzata; Karowicz-Bilińska, Agata; Suzin, Jacek

    2002-08-01

    Early detection of fetal risk is one of the main issues in today obstetrics. Ultrasound diagnostics plays a significant role, as the introduction of Doppler imaging method in the evaluation of blood flow has enabled non-invasive assessment of uteroplacental circulation. Therefore, we have analysed foetal three arteries: umbilical artery, middle cerebral artery and renal artery after determining the normal range for the analysed parameters. 1. Comparison of the obtained blood flow indices (S/D, RI, PI) in the umbilical artery, middle cerebral artery and renal artery of foetuses from normal and complicated full-term pregnancies. 2. Determination of indices: umbilical-cerebral and renal-cerebral in normal and pathological pregnancy. 3. Evaluation of feasibility of the analysed flow parameters for the detection of intrauterine foetal hypoxia. We have examined 151 women, who were divided into control group--101 pregnant women with normal pregnancy and study group--50 pregnant women with complicated pregnancy. All pregnant women underwent ultrasound examination using the Hitachi EUB 515 C (Japan) scanner with 3.5 MHz convex probe, connected to the colour pulsed Doppler. The study consisted of the biometric measurements and evaluation of the spectrum of blood flow in the umbilical artery, middle cerebral artery and renal artery. We have determined following indices: a) systolic-diastolic ratio S/D, resistance index RI, pulsatility index PI, b) umbilical-cerebral ratio P/M. (PI ua/PI mca), renal--cerebral ratio N/M (PI ra/PI mca). Statistically significant difference was found between the study and control groups for all the flow indices assessed (S/D, RI, PI) for the middle cerebral artery, for the indices P/M and N/M. (p < 0.001) and pulsatility index in the renal artery (p < 0.01). Similar, although slightly smaller difference (p < 0.05) was seen for the values of flow parameters in the umbilical artery. 1) Evaluation of blood flow in the middle cerebral artery, and in

  13. Dysfunctional regulation of ocular blood flow: A risk factor for glaucoma?

    Danny Moore

    2008-04-01

    Full Text Available Danny Moore, Alon Harris, Darrell WuDunn, Nisha Kheradiya, Brent Siesky1Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, IN, USAAbstract: Primary open angle glaucoma (OAG is a multifactorial optic neuropathy characterized by progressive retinal ganglion cell death and associated visual field loss. OAG is an emerging disease with increasing costs and negative outcomes, yet its fundamental pathophysiology remains largely undetermined. A major treatable risk factor for glaucoma is elevated intraocular pressure (IOP. Despite the medical lowering of IOP, however, some glaucoma patients continue to experience disease progression and subsequent irreversible vision loss. The scientific community continues to accrue evidence suggesting that alterations in ocular blood flow play a prominent role in OAG disease processes. This article develops the thesis that dysfunctional regulation of ocular blood flow may contribute to glaucomatous optic neuropathy. Evidence suggests that impaired vascular autoregulation renders the optic nerve head susceptible to decreases in ocular perfusion pressure, increases in IOP, and/or increased local metabolic demands. Ischemic damage, which likely contributes to further impairment in autoregulation, results in changes to the optic nerve head consistent with glaucoma. Included in this review are discussions of conditions thought to contribute to vascular regulatory dysfunction in OAG, including atherosclerosis, vasospasm, and endothelial dysfunction.Keywords: glaucoma, autoregulation, blood flow, atherosclerosis, vasospasm, endothelial dysfunction

  14. Determinants of systemic zero-flow arterial pressure.

    Brunner, M J; Greene, A S; Sagawa, K; Shoukas, A A

    1983-09-01

    Thirteen pentobarbital-anesthetized dogs whose carotid sinuses were isolated and perfused at a constant pressure were placed on total cardiac bypass. With systemic venous pressure held at 0 mmHg (condition 1), arterial inflow was stopped for 20 s at intrasinus pressures of 50, 125, and 200 mmHg. Zero-flow arterial pressures under condition 1 were 16.2 +/- 1.3 (SE), 13.8 +/- 1.1, and 12.5 +/- 0.8 mmHg, respectively. In condition 2, the venous outflow tube was clamped at the instant of stopping the inflow, causing venous pressure to rise. The zero-flow arterial pressures were 19.7 +/- 1.3, 18.5 +/- 1.4, and 16.4 +/- 1.2 mmHg for intrasinus pressures of 50, 125, and 200 mmHg, respectively. At all levels of intrasinus pressure, the zero-flow arterial pressure in condition 2 was higher (P less than 0.005) than in condition 1. In seven dogs, at an intrasinus pressure of 125 mmHg, epinephrine increased the zero-flow arterial pressure by 3.0 mmHg, whereas hexamethonium and papaverine decreased the zero-flow arterial pressure by 2 mmHg. Reductions in the hematocrit from 52 to 11% resulted in statistically significant changes (P less than 0.01) in zero-flow arterial pressures. Thus zero-flow arterial pressure was found to be affected by changes in venous pressure, hematocrit, and vasomotor tone. The evidence does not support the literally interpreted concept of the vascular waterfall as the model for the finite arteriovenous pressure difference at zero flow.

  15. Predictors of antegrade flow at internal carotid artery during carotid artery stenting with proximal protection.

    Harada, Kei; Kakumoto, Kosuke; Oshikata, Shogo; Fukuyama, Kozo

    2018-06-01

    Carotid artery stenting (CAS) with proximal occlusion effectively prevent distal cerebral embolism by flow arrest at internal carotid artery (ICA); however, the method can expose antegrade flow at ICA due to incomplete flow arrest. The aim of this study was to identify predictors of antegrade flow during CAS with proximal protection. We retrospectively analyzed clinical and angiographic data among 143 lesions treated with CAS with proximal protection by occluding the common carotid artery (CCA) and external carotid artery (ECA). Flow arrest or antegrade flow at ICA was confirmed by contrast injection during proximal protection. Antegrade flow at ICA was observed in 12 lesions (8.4%). Compared with lesions in which flow arrest of ICA was achieved, the diameter of the superior thyroid artery (STA) was significantly larger (2.4 ± 0.34 vs. 1.4 ± 0.68 mm, p protection should be combined with proximal protection for the lesions with antegrade flow to prevent distal migration of the carotid debris.

  16. Regional blood flow analysis and its relationship with arterial branch lengths and lumen volume in the coronary arterial tree

    Molloi, Sabee; Wong, Jerry T

    2007-01-01

    The limitations of visually assessing coronary artery disease are well known. These limitations are particularly important in intermediate coronary lesions (30-70% diameter stenosis) where it is difficult to determine whether a particular lesion is the cause of ischaemia. Therefore, a functional measure of stenosis severity is needed. The purpose of this study is to determine whether the expected maximum coronary blood flow in an arterial tree is predictable from its sum of arterial branch lengths or lumen volume. Using a computer model of a porcine coronary artery tree, an analysis of blood flow distribution was conducted through a network of millions of vessels that included the entire coronary artery tree down to the first capillary branch. The flow simulation results show that there is a linear relationship between coronary blood flow and the sum of its arterial branch lengths. This relationship holds over the entire arterial tree. The flow simulation results also indicate that there is a 3/4 er relation between coronary blood flow (Q) and the sum of its arterial lumen volume (V). Moreover, there is a linear relationship between normalized Q and normalized V raised to a power of 3/4 over the entire arterial tree. These results indicate that measured arterial branch lengths or lumen volumes can be used to predict the expected maximum blood flow in an arterial tree. This theoretical maximum blood flow, in conjunction with an angiographically measured blood flow, can potentially be used to calculate fractional flow reserve based entirely on angiographic data

  17. Unsteady 3D flow simulations in cranial arterial tree

    Grinberg, Leopold; Anor, Tomer; Madsen, Joseph; Karniadakis, George

    2008-11-01

    High resolution unsteady 3D flow simulations in major cranial arteries have been performed. Two cases were considered: 1) a healthy volunteer with a complete Circle of Willis (CoW); and 2) a patient with hydrocephalus and an incomplete CoW. Computation was performed on 3344 processors of the new half petaflop supercomputer in TACC. Two new numerical approaches were developed and implemented: 1) a new two-level domain decomposition method, which couples continuous and discontinuous Galerkin discretization of the computational domain; and 2) a new type of outflow boundary conditions, which imposes, in an accurate and computationally efficient manner, clinically measured flow rates. In the first simulation, a geometric model of 65 cranial arteries was reconstructed. Our simulation reveals a high degree of asymmetry in the flow at the left and right parts of the CoW and the presence of swirling flow in most of the CoW arteries. In the second simulation, one of the main findings was a high pressure drop at the right anterior communicating artery (PCA). Due to the incompleteness of the CoW and the pressure drop at the PCA, the right internal carotid artery supplies blood to most regions of the brain.

  18. Effect of TIPS placement on portal and splanchnic arterial blood flow in 4-dimensional flow MRI

    Stankovic, Zoran [Northwestern University, Department of Radiology, Feinberg School of Medicine, Chicago, IL (United States); University Medical Center Freiburg, Department of Diagnostic Radiology and Medical Physics, Freiburg (Germany); Roessle, Martin; Schultheiss, Michael [University Medical Center Freiburg, Department of Gastroenterology, Freiburg (Germany); Euringer, Wulf; Langer, Mathias [University Medical Center Freiburg, Department of Diagnostic Radiology and Medical Physics, Freiburg (Germany); Salem, Riad; Barker, Alex; Carr, James; Collins, Jeremy D. [Northwestern University, Department of Radiology, Feinberg School of Medicine, Chicago, IL (United States); Markl, Michael [Northwestern University, Department of Radiology, Feinberg School of Medicine, Chicago, IL (United States); Northwestern University, Department of Biomedical Engineering, McCormick School of Engineering, Chicago, IL (United States)

    2015-09-15

    To assess changes in portal and splanchnic arterial haemodynamics in patients undergoing transjugular intrahepatic portosystemic shunt (TIPS) using four-dimensional (4D) flow MRI, a non-invasive, non-contrast imaging technique. Eleven patients undergoing TIPS implantation were enrolled. K-t GRAPPA accelerated non-contrast 4D flow MRI of the liver vasculature was applied with acceleration factor R = 5 at 3Tesla. Flow analysis included three-dimensional (3D) blood flow visualization using time-resolved 3D particle traces and semi-quantitative flow pattern grading. Quantitative evaluation entailed peak velocities and net flows throughout the arterial and portal venous (PV) systems. MRI measurements were taken within 24 h before and 4 weeks after TIPS placement. Three-dimensional flow visualization with 4D flow MRI revealed good image quality with minor limitations in PV flow. Quantitative analysis revealed a significant increase in PV flow (562 ± 373 ml/min before vs. 1831 ± 965 ml/min after TIPS), in the hepatic artery (176 ± 132 ml/min vs. 354 ± 140 ml/min) and combined flow in splenic and superior mesenteric arteries (770 ml/min vs. 1064 ml/min). Shunt-flow assessment demonstrated stenoses in two patients confirmed and treated at TIPS revision. Four-dimensional flow MRI might have the potential to give new information about the effect of TIPS placement on hepatic perfusion. It may explain some unexpected findings in clinical observation studies. (orig.)

  19. In vitro and in vivo studies of pulmonary artery flow

    Sahn, D.J.; Yoganathan, A.P.

    1986-01-01

    A variety of interesting intracardiac flow patterns have been recorded by pulsed and continuous wave Doppler technologies in humans with heart disease. Some of these patterns have, in fact, been difficult to explain and are now more easily understood using color Doppler flow mapping systems which show the spatial location of flow. The authors performed a number of studies in patients, as well as studies in in vitro systems to model some of the phenomenon that the authors observed in the pulmonary artery. Their studies with Doppler flow mapping in the clinical situation, in the in vitro model, and in the animal models of congenital heart disorders lend insights into the complex hydrodynamics present in the pulmonary artery

  20. Nocturnal foot blood flow in patients with arterial insufficiency

    Jelnes, Rolf; Tønnesen, K H

    1984-01-01

    Twenty-four hour continuous recording of xenon (133Xe) wash-out from the forefoot was performed on patients with normal circulations (n = 10) and on patients with different degrees of arterial insufficiency (n = 36). During day hours the calculated subcutaneous blood flow in the forefoot was on a...

  1. Calculation of arterial wall temperature in atherosclerotic arteries: effect of pulsatile flow, arterial geometry, and plaque structure

    Kim Taehong

    2007-03-01

    Full Text Available Abstract Background This paper presents calculations of the temperature distribution in an atherosclerotic plaque experiencing an inflammatory process; it analyzes the presence of hot spots in the plaque region and their relationship to blood flow, arterial geometry, and inflammatory cell distribution. Determination of the plaque temperature has become an important topic because plaques showing a temperature inhomogeneity have a higher likelihood of rupture. As a result, monitoring plaque temperature and knowing the factors affecting it can help in the prevention of sudden rupture. Methods The transient temperature profile in inflamed atherosclerotic plaques is calculated by solving an energy equation and the Navier-Stokes equations in 2D idealized arterial models of a bending artery and an arterial bifurcation. For obtaining the numerical solution, the commercial package COMSOL 3.2 was used. The calculations correspond to a parametric study where arterial type and size, as well as plaque geometry and composition, are varied. These calculations are used to analyze the contribution of different factors affecting arterial wall temperature measurements. The main factors considered are the metabolic heat production of inflammatory cells, atherosclerotic plaque length lp, inflammatory cell layer length lmp, and inflammatory cell layer thickness dmp. Results The calculations indicate that the best location to perform the temperature measurement is at the back region of the plaque (0.5 ≤ l/lp ≤ 0.7. The location of the maximum temperature, or hot spot, at the plaque surface can move during the cardiac cycle depending on the arterial geometry and is a direct result of the blood flow pattern. For the bending artery, the hot spot moves 0.6 millimeters along the longitudinal direction; for the arterial bifurcation, the hot spot is concentrated at a single location due to the flow recirculation observed at both ends of the plaque. Focusing on the

  2. Secondary flow structures under stent-induced perturbations for cardiovascular flow in a curved artery model

    Glenn, Autumn L.; Bulusu, Kartik V.; Shu Fangjun; Plesniak, Michael W.

    2012-01-01

    Secondary flows within curved arteries with unsteady forcing result from amplified centrifugal instabilities and are expected to be driven by the rapid accelerations and decelerations inherent in physiological waveforms. These secondary flows may also affect the function of curved arteries through pro-atherogenic wall shear stresses, platelet residence time and other vascular response mechanisms. Planar PIV measurements were performed under multi-harmonic non-zero-mean and physiological carotid artery waveforms at various locations in a rigid bent-pipe curved artery model. Results revealed symmetric counter-rotating vortex pairs that developed during the acceleration phases of both multi-harmonic and physiological waveforms. An idealized stent model was placed upstream of the bend, which initiated flow perturbations under physiological inflow conditions. Changes in the secondary flow structures were observed during the systolic deceleration phase (t/T ≈ 0.20–0.50). Proper Orthogonal Decomposition (POD) analysis of the flow morphologies under unsteady conditions indicated similarities in the coherent secondary-flow structures and correlation with phase-averaged velocity fields. A regime map was created that characterizes the kaleidoscope of vortical secondary flows with multiple vortex pairs and interesting secondary flow morphologies. This regime map in the curved artery model was created by plotting the secondary Reynolds number against another dimensionless acceleration-based parameter marking numbered regions of vortex pairs.

  3. Secondary flow structures under stent-induced perturbations for cardiovascular flow in a curved artery model

    Glenn, Autumn L.; Bulusu, Kartik V. [Department of Mechanical and Aerospace Engineering, George Washington University, 801 22nd Street, NW., Washington, DC 20052 (United States); Shu Fangjun [Department of Mechanical and Aerospace Engineering, New Mexico State University, MSC 3450, P.O. Box 30001, Las Cruces, NM 88003-8001 (United States); Plesniak, Michael W., E-mail: plesniak@gwu.edu [Department of Mechanical and Aerospace Engineering, George Washington University, 801 22nd Street, NW., Washington, DC 20052 (United States)

    2012-06-15

    Secondary flows within curved arteries with unsteady forcing result from amplified centrifugal instabilities and are expected to be driven by the rapid accelerations and decelerations inherent in physiological waveforms. These secondary flows may also affect the function of curved arteries through pro-atherogenic wall shear stresses, platelet residence time and other vascular response mechanisms. Planar PIV measurements were performed under multi-harmonic non-zero-mean and physiological carotid artery waveforms at various locations in a rigid bent-pipe curved artery model. Results revealed symmetric counter-rotating vortex pairs that developed during the acceleration phases of both multi-harmonic and physiological waveforms. An idealized stent model was placed upstream of the bend, which initiated flow perturbations under physiological inflow conditions. Changes in the secondary flow structures were observed during the systolic deceleration phase (t/T Almost-Equal-To 0.20-0.50). Proper Orthogonal Decomposition (POD) analysis of the flow morphologies under unsteady conditions indicated similarities in the coherent secondary-flow structures and correlation with phase-averaged velocity fields. A regime map was created that characterizes the kaleidoscope of vortical secondary flows with multiple vortex pairs and interesting secondary flow morphologies. This regime map in the curved artery model was created by plotting the secondary Reynolds number against another dimensionless acceleration-based parameter marking numbered regions of vortex pairs.

  4. Alteration in ocular blood flow and its effect on the progression of glaucoma

    Sher Zaman Safi

    2017-04-01

    Full Text Available Glaucoma is a multifactorial neurodegenerative disease that can result in permanent vision loss by damaging optic nerves due to higher pressure in the eye. Although most of the fundamental pathophysiological mechanisms involved in glaucoma are undetermined but alteration in ocular blood flow(OBFin tissues such as optic nerve, retina, choroid and iris is an important risk factor for glaucoma. Various factors such as limited knowledge of the factors causing optic nerve damage, confusion in the measurement assays and lack of therapies, make hindrances in the understanding of glaucoma. Researchers are continuously accumulating evidence to suggest that alterations in OBF play important role in the pathogenesis of glaucoma but most of the times they have diverse and contradictory conclusions regarding changes in the OBF and risk of glaucoma. In this article we have reviewed different aspects of glaucoma and the effect of OBF in the disease progression

  5. Dopexamine increases internal mammary artery blood flow following coronary artery bypass grafting.

    Flynn, Michael J

    2012-02-03

    OBJECTIVE: Vasoactive agents and inotropes influence conduit-coronary blood flow following coronary artery bypass grafting (CABG). It was hypothesized that dopexamine hydrochloride, a dopamine A-1 (DA-1) and beta(2) agonist would increase conduit-coronary blood flow. A prospective randomized double blind clinical trial was carried out to test this hypothesis. DA-1 receptors have previously been localized to human left ventricle. METHODS: Twenty-six American Society of Anaesthesiology class 2-3 elective coronary artery bypass graft patients who did not require inotropic support on separation from cardiopulmonary bypass (CPB) were studied. According to a randomized allocation patients received either dopexamine (1 microg\\/kg per min) or placebo (saline) by intravenous infusion for 15 min. Immediately prior to and at 5,10 and 15 min of infusion, blood flow through the internal mammary and vein grafts (Transit time flow probes, Transonic Ltd.), heart rate, cardiac index, mean arterial pressure and pulmonary haemodynamics were noted. The data were analysed using multivariate analysis of variance. RESULTS: Low-dose dopexamine (1 microg\\/kg per min) caused a significant increase in mammary graft blood flow compared to placebo at 15 min of infusion (P=0.028, dopexamine group left internal mammary artery (LIMA) flow of 43.3+\\/-14.2 ml\\/min, placebo group LIMA flow at 26.1+\\/-16.3 ml\\/min). Dopexamine recipients demonstrated a non-significant trend to increased saphenous vein graft flow (P=0.059). Increased heart rate was the only haemodynamic change induced by dopexamine (P=0.004, dopexamine group at 85.2+\\/-9.6 beats\\/min and placebo group at 71.1+\\/-7.6 beats\\/min after 15 min of infusion). CONCLUSION: This study demonstrates that administration of dopexamine (1 microg\\/kg per min) was associated with a significant increase in internal mammary artery graft blood flow with mild increase in heart rate being the only haemodynamic change. Low-dose dopexamine may

  6. Parameters of Blood Flow in Great Arteries in Hypertensive ISIAH Rats with Stress-Dependent Arterial Hypertension.

    Seryapina, A A; Shevelev, O B; Moshkin, M P; Markel', A L

    2016-08-01

    Magnetic resonance angiography was used to examine blood flow in great arteries of hypertensive ISIAH and normotensive Wistar rats. In hypertensive ISIAH rats, increased vascular resistance in the basin of the abdominal aorta and renal arteries as well as reduced fraction of total renal blood flow were found. In contrast, blood flow through both carotid arteries in ISIAH rats was enhanced, which in suggests more intensive blood supply to brain regulatory centers providing enhanced stress reactivity of these rats characterized by stress-dependent arterial hypertension.

  7. Middle cerebral artery flow velocity waveforms in fetal hypoxaemia.

    Vyas, S; Nicolaides, K H; Bower, S; Campbell, S

    1990-09-01

    In 81 small-for-gestational age fetuses (SGA) colour flow imaging was used to identify the fetal middle cerebral artery for subsequent pulsed Doppler studies. Impedence to flow (pulsatility index; PI) was significantly lower, and mean blood velocity was significantly higher, than the respective reference ranges with gestation. Fetal blood sampling by cordocentesis was performed in all SGA fetuses and a significant quadratic relation was found between fetal hypoxaemia and the degree of reduction in the PI of FVWs from the fetal middle cerebral artery. Thus, maximum reduction in PI is reached when the fetal PO2 is 2-4 SD below the normal mean for gestation. When the oxygen deficit is greater there is a tendency for the PI to rise, and this presumably reflects the development of brain oedema.

  8. Ultrasonic Doppler measurement of renal artery blood flow

    Freund, W. R.; Meindl, J. D.

    1975-01-01

    An extensive evaluation of the practical and theoretical limitations encountered in the use of totally implantable CW Doppler flowmeters is provided. Theoretical analyses, computer models, in-vitro and in-vivo calibration studies describe the sources and magnitudes of potential errors in the measurement of blood flow through the renal artery, as well as larger vessels in the circulatory system. The evaluation of new flowmeter/transducer systems and their use in physiological investigations is reported.

  9. Abnormal arterial flows by a distributed model of the fetal circulation.

    van den Wijngaard, Jeroen P H M; Westerhof, Berend E; Faber, Dirk J; Ramsay, Margaret M; Westerhof, Nico; van Gemert, Martin J C

    2006-11-01

    Modeling the propagation of blood pressure and flow along the fetoplacental arterial tree may improve interpretation of abnormal flow velocity waveforms in fetuses. The current models, however, either do not include a wide range of gestational ages or do not account for variation in anatomical, vascular, or rheological parameters. We developed a mathematical model of the pulsating fetoumbilical arterial circulation using Womersley's oscillatory flow theory and viscoelastic arterial wall properties. Arterial flow waves are calculated at different arterial locations from which the pulsatility index (PI) can be determined. We varied blood viscosity, placental and brain resistances, placental compliance, heart rate, stiffness of the arterial wall, and length of the umbilical arteries. The PI increases in the umbilical artery and decreases in the cerebral arteries, as a result of increasing placental resistance or decreasing brain resistance. Both changes in resistance decrease the flow through the placenta. An increased arterial stiffness increases the PIs in the entire fetoplacental circulation. Blood viscosity and peripheral bed compliance have limited influence on the flow profiles. Bradycardia and tachycardia increase and decrease the PI in all arteries, respectively. Umbilical arterial length has limited influence on the PI but affects the mean arterial pressure at the placental cord insertion. The model may improve the interpretation of arterial flow pulsations and thus may advance both the understanding of pathophysiological processes and clinical management.

  10. Measurement of Blood Flow in an Intracranial Artery Bypass From the Internal Maxillary Artery by Intraoperative Duplex Sonography.

    Yu, Zaitao; Shi, Xiang'en; Brohi, Shams Raza; Qian, Hai; Liu, Fangjun; Yang, Yang

    2017-02-01

    This study explored the hemodynamic characteristics of a subcranial-intracranial bypass from the internal maxillary artery by measuring blood flow on intraoperative duplex sonography. The hemodynamic parameters of the internal maxillary artery (n = 20), radial artery (n = 20), internal maxillary artery-middle cerebral artery bypass (n = 42), and internal maxillary artery-posterior cerebral artery bypass (n = 9) were measured by intraoperative duplex sonography. There was no significant difference in the internal diameters of the internal maxillary and radial arteries (mean ± SD, 2.51 ± 0.34 versus 2.56 ± 0.22 mm; P = .648). The mean radial artery graft length for subcranial-intracranial bypasses was 88.5 ± 12.78 mm (95% confidence interval [CI], 80.8-90.2 mm). Internal maxillary artery-middle cerebral artery bypasses required a shorter radial artery graft than internal maxillary artery-posterior cerebral artery bypasses (77.8 ± 2.47 versus 104.8 ± 4.77 mm; P = .001). The mean flow volumes were 85.3 ± 18.5 mL/min (95% CI, 76.6-93.9 mL/min) for the internal maxillary artery, 72.6 ± 26.4 mL/min (95% CI, 64.3-80.9 mL/min) for internal maxillary artery-middle cerebral artery bypasses, and 45.4 ± 6.7 mL/min (95% CI, 40.7-50.0 mL/min) for internal maxillary artery-posterior cerebral artery bypasses. All grafts were opened after the success of the salvage procedures had been established, and the early patency rates (1 month after the operation) were 95% for internal maxillary artery-middle cerebral artery bypasses and 100% the internal maxillary artery-posterior cerebral artery bypasses. Measurement of blood flow by intraoperative sonography can be helpful in decision making and predicting graft patency and success after neurosurgical bypass procedures. © 2016 by the American Institute of Ultrasound in Medicine.

  11. FDM Analysis for Blood Flow through Stenosed Tapered Arteries

    Sankar DS

    2010-01-01

    Full Text Available Abstract A computational model is developed to analyze the unsteady flow of blood through stenosed tapered narrow arteries, treating blood as a two-fluid model with the suspension of all the erythrocytes in the core region as Herschel-Bulkley fluid and the plasma in the peripheral layer as Newtonian fluid. The finite difference method is employed to solve the resulting system of nonlinear partial differential equations. The effects of stenosis height, peripheral layer thickness, yield stress, viscosity ratio, angle of tapering and power law index on the velocity, wall shear stress, flow rate and the longitudinal impedance are analyzed. It is found that the velocity and flow rate increase with the increase of the peripheral layer thickness and decrease with the increase of the angle of tapering and depth of the stenosis. It is observed that the flow rate decreases nonlinearly with the increase of the viscosity ratio and yield stress. The estimates of the increase in the longitudinal impedance to flow are considerably lower for the two-fluid Herschel-Bulkley model compared with those of the single-fluid Herschel-Bulkley model. Hence, it is concluded that the presence of the peripheral layer helps in the functioning of the diseased arterial system.

  12. Ocular Pharmacokinetics of Dorzolamide and Brinzolamide After Single and Multiple Topical Dosing: Implications for Effects on Ocular Blood FlowS⃞

    Kadam, Rajendra S.; Jadhav, Gajanan; Ogidigben, Miller

    2011-01-01

    Ophthalmic carbonic anhydrase inhibitors have been shown to improve retinal and optic nerve blood flow. However, the relative tissue distributions of commercially available carbonic anhydrase inhibitors to the optic nerve are not known. The objective of this study was to compare the ocular pharmacokinetics and tissue distribution profiles of dorzolamide and brinzolamide after single and multiple topical applications. Pigmented rabbits were treated with single or multiple topical administrations of 30 μl of Trusopt (dorzolamide hydrochloride ophthalmic solution, 2%) to one eye and 30 μl of Azopt (brinzolamide ophthalmic suspension, 1%) to the other eye. Rabbits were euthanized at 10 predetermined time intervals over a period of 24 h, and ocular tissues and plasma samples were collected. For multiple dosing, rabbits were dosed twice per day with an 8-h interval between two doses, groups of rabbits were euthanized at 7, 14, and 21 days at 1 h after the last dose, and ocular tissues and plasma samples were collected. Drug levels in tissue samples were measured using liquid chromatography/tandem mass spectrometry. Pharmacokinetic parameters (Cmax, Tmax, and AUC0–24) were estimated by noncompartmental analysis. After a single dose, dorzolamide delivery (AUC0–24) to the aqueous humor, anterior sclera, posterior sclera, anterior retina, posterior retina, anterior vitreous, and optic nerve was 2-, 7-, 2.6-, 1.4-, 1.9-, 1.2-, and 9-fold higher than those of brinzolamide. Cmax was 2- to 5-fold higher for dorzolamide than that of brinzolamide in all of the ocular tissue. After multiple dosing, dorzolamide levels in the aqueous humor, sclera, retina, vitreous humor, and optic nerve were higher than those of brinzolamide, but statistical significance was achieved only with aqueous humor, vitreous humor, and optic nerve. Dorzolamide levels in the aqueous humor, anterior vitreous, posterior vitreous, and optic nerve were 1.4- to 3.2-, 2.4- to 2.7-, 2.2- to 4.5-, and 2.4- to

  13. Pulmonary scanning: quantitative evaluation of pulmonary arterial flow

    Papaleo Netto, M; Fujioka, T [Sao Paulo Univ. (Brazil). Faculdade de Medicina; Dias Neto, A; Carvalho, N [Sao Paulo Univ. (Brazil). Centro de Medicina Nuclear

    1974-01-01

    From ten normal subjects of both sexes, the quantitative regional blood flow of the pulmonary artery was evaluated using scanning with macroaggregated radio-iodinated (/sup 131/I) albumin. It was possible to conclude that: the digital recording of data (counts/cm/sup 2/), from any particular area of interest, is the best method for this evaluation; the lung, even being a thick organ, can be well studied by quantitative scanning, since its structure doesn't hinder the passage of radiations because it is covered only by the thoracic wall; scanning can be used to evaluate regional perfusion of the pulmonary artery, based on the proportionality between density of aggregates and blood flux in the different areas; the concentration of macroaggregates on the lung's superior section never reaches more than 40% of the radioactivity of the whole lung; there is no significant difference between left and right lungs, concerning the relationship between radioactivity on the superior section and the total area and quantitative analysis of pulmonary artery flow by means of scanning is a possible, reliable, and safe technique, without distress for the patient.

  14. Pulmonary scanning: quantitative evaluation of pulmonary arterial flow

    Papaleo Netto, M.; Fujioka, T.; Dias Neto, A.; Carvalho, N.

    1974-01-01

    From ten normal subjects of both sexes, the quantitative regional blood flow of the pulmonary artery was evaluated using scanning with macroaggregated radio-iodinated ( 131 I) albumin. It was possible to conclude that: the digital recording of data (counts/cm 2 ), from any particular area of interest, is the best method for this evaluation; the lung, even being a thick organ, can be well studied by quantitative scanning, since its structure doesn't hinder the passage of radiations because it is covered only by the thoracic wall; scanning can be used to evaluate regional perfusion of the pulmonary artery, based on the proportionality between density of aggregates and blood flux in the different areas; the concentration of macroaggregates on the lung's superior section never reaches more than 40% of the radioactivity of the whole lung; there is no significant difference between left and right lungs, concerning the relationship between radioactivity on the superior section and the total area and quantitative analysis of pulmonary artery flow by means of scanning is a possible, reliable and safe technique, without distress for the patient [pt

  15. Flow Characteristics Near to Stent Strut Configurations on Femoropopliteal Artery

    Paisal, Muhammad Sufyan Amir; Fadhil Syed Adnan, Syed; Taib, Ishkrizat; Ismail, Al Emran; Kamil Abdullah, Mohammad; Nordin, Normayati; Seri, Suzairin Md; Darlis, Nofrizalidris

    2017-08-01

    Femoropopiteal artery stenting is a common procedure suggested by medical expert especially for patient who is diagnosed with severe stenosis. Many researchers reported that the growth of stenosis is significantly related to the geometry of stent strut configuration. The different shapes of stent geometry are presenting the different flow pattern and re-circulation in stented femoropopliteal artery. The blood flow characteristics near to the stent geometry are predicted for the possibility of thrombosis and atherosclerosis to be formed as well as increase the growth of stenosis. Thus, this study aims to determine the flow characteristic near to stent strut configuration based on different hemodynamic parameters. Three dimensional models of stent and simplified femoropopliteal artery are modelled using computer aided design (CAD) software. Three different models of stent shapes; hexagon, circle and rectangle are simulated using computational fluid dynamic (CFD) method. Then, parametric study is implemented to predict the performance of stent due to hemodynamic differences. The hemodynamic parameters considered are pressure, velocity, low wall shear stress (WSSlow) and wall shear stress (WSS). From the observation, flow re-circulation has been formed for all simulated stent models which the proximal region shown the severe vortices. However, rectangular shape of stent strut (Type P3) shows the lowest WSSlow and the highest WSS between the range of 4 dyne/cm2 and 70 dyne/cm2. Stent Type P3 also shows the best hemodynamic stent performance as compare to others. In conclusion, Type P3 has a favourable result in hemodynamic stent performance that predicted less probability of thrombosis and atherosclerosis to be formed as well as reduces the growth of restenosis.

  16. The effect of ultrasound on arterial blood flow: 1. Steady fully developed flow

    Bestman, A.R.

    1990-12-01

    The paper models the effects of ultrasound heating of the tissues and the resultant perturbation on blood flow in the arteries and veins. It is assumed that the blood vessel is rigid and the undisturbed flow is fully developed. Acoustical perturbation on this Poiseuille flow, for the general three-dimensional flow with heat transfer in an infinitely long pipe is considered. Closed form analytical solutions are obtained to the problem. It is discovered that the effects of the ultrasound heating are concentrated at the walls of the blood vessels. (author). 4 refs

  17. Ocular Hypertension

    ... Español Eye Health / Eye Health A-Z Ocular Hypertension Sections What Is Ocular Hypertension? Ocular Hypertension Causes ... Hypertension Diagnosis Ocular Hypertension Treatment What Is Ocular Hypertension? Leer en Español: ¿Qué es la hipertensión ocular? ...

  18. Longitudinal changes of ocular blood flow using laser speckle flowgraphy during normal pregnancy.

    Takahiro Sato

    Full Text Available Innovative laser speckle flowgraphy (LSFG enables noninvasive evaluation of retinal microcirculation and the usefulness has been reported in the field of ophthalmology. LSFG has allowed us to measure the real time changes of retinal blood flow without pupillary dilatations and contrast media. Herein, we investigated the change of retinal blood flow in normal pregnant women during gestation using LSFG.A prospective cohort study was conducted in 53 pregnant women who visited our institution between January, 2013 and July, 2014. Finally, a total of 41 participants without any obstetric complications were available for evaluation. Retinal blood flow was measured with LSFG in a total of 4 times during pregnancy (T1. 11-13 weeks, T2. 19-21 weeks, T3. 28-30 weeks, T4. 34-36 weeks and mean blur rate (MBR, blowout score (BOS, flow acceleration index (FAI, and resistive index (RI are analyzed from these measurements. Relations between LSFG parameters and mean arterial blood pressure (MAP are determined throughout pregnancy.MBR showed no significant changes throughout pregnancy. BOS showed a tendency to increase in the 3rd trimester. FAI values showed a slight increase from the 1st to 2nd trimester while a significant decrease was noted in the 3rd trimester. RI exhibited no changes between the 1st and 2nd trimesters, values decreased significantly after the 3rd trimester. MAP was positively correlated with BOS, and negatively correlated with FAI and RI.The present study clearly demonstrated that profiles of LSFG parameters demonstrated a decrease of resistance in retinal blood vessels. These changes in indices provide a highly sensitive reflection of physiological changes in vascular resistance due to pregnancy. Thus, LSFG may be useful, as a non-invasive, diagnostic tool to detect pregnancy related disorders such as preeclampsia.

  19. MR measurement of coronary arterial blood flow velocity. Evaluation of age, stenosis and drugs as factors affecting coronary blood flow

    Taoka, Yoshiaki; Harada, Masafumi; Nishitani, Hiromu; Yukinaka, Michiko; Nomura, Masahiro

    1998-01-01

    Coronary arterial blood flow velocity was measured using MRI. Two types of phase contrast methods were used for the measurements, one of which exhibited good resolving power whereas the other provided more distinct images acquired while the subject patients held their breath. Before measuring coronary arterial blood flow velocity, accuracy of the two phase contrast methods was evaluated using a phantom. The results obtained with both methods largely agreed with the values obtained using the phantom. Using both methods, the patterns of coronary arterial blood flow over one cardiac cycle were essentially identical. A peak was noted in late systole or in early diastole in the right coronary artery, whereas in the left coronary artery, a peak was noted somewhat later in diastole. In healthy volunteers, no significant difference in the maximal flow velocity in the coronary arteries was found from one age group to another. Among patients with coronary arterial stenosis, coronary arterial blood flow velocity central to the area of stenosis was lower than that observed in the healthy volunteers. Coronary arterial blood flow velocity was observed to decrease after administration of isosorbide dinitrate and increased following administration of nifedipine. (author)

  20. Vertebral Artery Diameter and Flow: Nature or Nurture.

    Tarnoki, Adam Domonkos; Fejer, Bence; Tarnoki, David Laszlo; Littvay, Levente; Lucatelli, Pierleone; Cirelli, Carlo; Fanelli, Fabrizio; Sacconi, Beatrice; Fagnani, Corrado; Medda, Emanuela; Farina, Filippo; Meneghetti, Giorgio; Horvath, Tamas; Pucci, Giacomo; Schillaci, Giuseppe; Stazi, Maria Antonietta; Baracchini, Claudio

    2017-09-01

    In contrast with the carotid arteries, the vertebral arteries (VAs) show considerable variation in length, caliber, and vessel course. This study investigated whether the variation in diameter and flow characteristics of the VAs might be inherited. A total of 172 Italian twins from Padua, Perugia, and Terni (54 monozygotic, 32 dizygotic) recruited from the Italian Twin Registry underwent B-mode and pulsed-wave Doppler ultrasound assessment of their VAs. VA diameters, peak systolic velocity (PSV) and end diastolic velocity (EDV) were assessed at the level of a horizontal V2 segment. Univariate quantitative genetic modeling was performed. Fourteen percent of the sample had VA hypoplasia. Within pair correlation in monozygotic twins was higher than in dizygotics (.552 vs. .229) for VA diameter. Age- and sex-adjusted genetic effect, under the most parsimonious model, accounted for 54.7% (95% CI: 42.2-69.1%) of the variance of VA diameter, and unshared environmental effect for 45.3% (95% CI: 30.9-57.8%). No heritability was found for the PSV of VA, but shared (34.1%; 95% CI: 16.7-53.7%) and unshared (65.9%; 95% CI: 45.9-83.1%) environmental factors determined the variance. EDV of VA is moderately genetically influenced (42.4%; 95% CI: 16.1-64.9%) and also determined by the unshared environment (57.6%; 95% CI: 34.7-83.7%). The diameter of the VAs is moderately genetically determined. Different factors influence the PSV and EDV of VAs, which may highlight the complex hemodynamic background of VA flow and help to understand the vertebral flow anomalies found by ultrasound. Copyright © 2017 by the American Society of Neuroimaging.

  1. Merging flows in an arterial confluence : The vertebro-basilar junction

    Ravensbergen, J; Krijger, JKB; Hillen, B; Hoogstraten, HW

    1995-01-01

    The basilar artery is one of the three vessels providing the blood supply to the human brain. It arises from the confluence of the two vertebral arteries. In fact, it is the only artery of this size in the human body arising from a confluence instead of a bifurcation. Earlier work, concerning flow

  2. Aging decreases CO2 reactivity in the retinal artery, but not in the ocular choroidal vessels; a cross-sectional study.

    Miyaji, Akane; Ikemura, Tsukasa; Hayashi, Naoyuki

    2018-04-14

    The CO2 reactivity is often used to assess vascular function, but it is still unclear whether this reactivity is affected by aging. To investigate the effects of aging on the CO2 reactivity in ocular and cerebral vessels, both of which are highly sensitive to hypercapnia, we compared the CO2 reactivity in the retinal artery (RA), retinal and choroidal vessels (RCV), optic nerve head (ONH), and middle cerebral artery (MCA) between young and middle-aged subjects. We measured the CO2 reactivity in 14 young and 11 middle-aged males using laser-speckle flowgraphy during a 3-min inhalation of CO2-rich air. The CO2 reactivity in the RA and ONH were lower in the middle-aged group than in the young group, but no significant effect of age was observed in the RCV or MCA. The CO2 reactivity in the RA and ONH were correlated significantly with age, whereas those in the RCV or MCA were not. These findings suggest that there are regional differences in the effect of age on the CO2 reactivity among not only ocular and cerebral vessels, but also the retinal and choroidal vessels, even though these vessels are in neighboring areas.

  3. Unraveling the relationship between arterial flow and intra-aneurysmal hemodynamics.

    Morales, Hernán G; Bonnefous, Odile

    2015-02-26

    Arterial flow rate affects intra-aneurysmal hemodynamics but it is not clear how their relationship is. This uncertainty hinders the comparison among studies, including clinical evaluations, like a pre- and post-treatment status, since arterial flow rates may differ at each time acquisition. The purposes of this work are as follows: (1) To study how intra-aneurysmal hemodynamics changes within the full physiological range of arterial flow rates. (2) To provide characteristic curves of intra-aneurysmal velocity, wall shear stress (WSS) and pressure as functions of the arterial flow rate. Fifteen image-based aneurysm models were studied using computational fluid dynamics (CFD) simulations. The full range of physiological arterial flow rates reported in the literature was covered by 11 pulsatile simulations. For each aneurysm, the spatiotemporal-averaged blood flow velocity, WSS and pressure were calculated. Spatiotemporal-averaged velocity inside the aneurysm linearly increases as a function of the mean arterial flow (minimum R(2)>0.963). Spatiotemporal-averaged WSS and pressure at the aneurysm wall can be represented by quadratic functions of the arterial flow rate (minimum R(2)>0.996). Quantitative characterizations of spatiotemporal-averaged velocity, WSS and pressure inside cerebral aneurysms can be obtained with respect to the arterial flow rate. These characteristic curves provide more information of the relationship between arterial flow and aneurysm hemodynamics since the full range of arterial flow rates is considered. Having these curves, it is possible to compare experimental studies and clinical evaluations when different flow conditions are used. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Functional assessment of the hepatic arterial blood flow by pharmacoradiography

    Stellamor, K; Hruby, W; Peschl, L

    1981-12-01

    By means of celiacography it was possible to demonstrate that parenteral medication with parathormone creates a selective dilatation of the liver vessels in man, provided that they are dilatable. This hemodynamic hormone effect could not be traced in the other mesenteric vessels. The increase of portal hypertension resulting from cirrhosis leads to a loss of the dilating ability of liver vessels. This regressive reaction is well demonstrated on the parathormone-celiacogram. Thus a functional assessment of the hepatic blood flow is possible. The extent of the dilatability of the liver artery seems to be of great importance for the prognosis and indication of the porto-systemic shunt-operation. Moreover we could show that an increase in the liver perfusion demonstrates pathologic liver processes in a better way.

  5. Normal reference values for vertebral artery flow volume by color Doppler sonography in Korean adults

    Hong, Hyun Sook; Cha, Jang Gyu; Park, Seong Jin; Joh, Joon Hee; Park, Jai Soung; Kim, Dae Ho; Lee, Hae Kyung; Ahn, Hyun Cheol [Soonchunhyang University Bucheon Hospital, Bucheon (Korea, Republic of)

    2003-09-15

    Vertebrobasilar ischemia has been attributed to a reduction of net vertebral artery flow volume. This study was to establish the reference values for the flow volume of the vertebral artery using color Doppler sonography in the normal Korea adults. Thirty five normal Korea adults without any underlying disease including hypertension, hyperlipidemia, diabetes, heart disease, obesity (body mas index>30), or carotid artery stenosis was included. There were 17 males and 18 females, age ranged from 20 to 53 years (average=32.86 years). Flow velocities and vessel diameters were recorded in the intertransverse (V2) segment, usually at C5-6 level, bilaterally. The flow volume (Q) was calculated. (Q=time averaged mean velocity x cross sectional area of vessel) A lower Flow velocity and smaller vessel diameter were measured on the right side compared to those of the left side, resulting in a lower flow volume. The calculated flow volumes using the equation were 77.0 +- 39.7 ml/min for the right side and 127.6 +- 71.0 ml/min for the left side (p=0.0001) while the net vertebral artery flow volume was 204.6 +- 81.8 ml/min. Decrease in the vertebral artery flow volume was statistically significant with advanced age. (r=-0.36, p=0.032). Vertebral artery blood flow volume was 191.20 +- 59.19 ml/min in male, and 217.28 +- 98.67 ml/min in female (p=0.6). The normal range for the net vertebral artery flow volume defined by the 5th to 95th percentiles was between 110.06 and 364.1 ml/min. The normal range for the net vertebral artery flow volume was between 110.06 and 364.1 ml/min. Vertebral artery flow volume decreased with the increase of age. However, gender did not affect the blood flow volume.

  6. Analysis of transit time flow of the right internal thoracic artery anastomosed to the left anterior descending artery compared to the left internal thoracic artery

    Milani, Rodrigo; de Moraes, Daniela; Sanches, Aline; Jardim, Rodrigo; Lumikoski, Thais; Miotto, Gabriela; Santana, Vitor Hugo; Brofman, Paulo Roberto

    2014-01-01

    Introduction We evaluated with transit time flow the performance of the right and left thoracic arteries when used as a graft for the left anterior descending artery. Methods Fifty patients undergoing surgery for myocardial revascularization without cardiopulmonary bypass were divided into two groups. In group A patients received graft of right internal mammary artery to the anterior interventricular branch. In group B patients received graft of left internal mammary artery to the same branch. At the end of the operation the flow was assessed by measuring transit time. Results In group A, mean age was 60.6±9.49 years. The average height and weight of the group was 80.4±10.32 kg and 169.2±6.86 cm. The average number of grafts per patient in this group was 3.28±1.49. The mean flow and distal resistance obtained in right internal thoracic artery was 42.1±23.4 ml/min and 2.8±0.9 respectively. In group B, the mean age was 59.8±9.7 years. The average height and weight of this group was 77.7±14.22 kg and 166.0±8.2 cm. The average number of grafts per patient in this group was 3.08 ±0.82. The mean flow and distal resistance observed in this group was 34.2±19.1 ml/min and 2.0±0.7. There were no deaths in this series. Conclusion Right internal mammary artery presented a similar behavior to left internal mammary artery when anastomosed to the anterior interventricular branch of the left coronary artery. There was no statistical difference between the measured flow obtained between both arteries. PMID:25140463

  7. A case of atherosclerotic inferior mesenteric artery aneurysm secondary to high flow state.

    Troisi, Nicola; Esposito, Giovanni; Cefalì, Pietro; Setti, Marco

    2011-07-01

    Inferior mesenteric artery aneurysms are very rare and they are among the rarest of visceral artery aneurysms. Sometimes, the distribution of the blood flow due to chronic atherosclerotic occlusion of some arteries can establish an increased flow into a particular supplying district (high flow state). A high flow state in a stenotic inferior mesenteric artery in compensation for a mesenteric occlusive disease can produce a rare form of aneurysm. We report the case of an atherosclerotic inferior mesenteric aneurysm secondary to high flow state (association with occlusion of the celiac trunk and severe stenosis of the superior mesenteric artery), treated by open surgical approach. Copyright © 2011 Society for Vascular Surgery. Published by Mosby, Inc. All rights reserved.

  8. Functional dilatation and medial remodeling of the renal artery in response to chronic increased blood flow.

    Roan, Jun-Neng; Yeh, Chin-Yi; Chiu, Wen-Cheng; Lee, Chou-Hwei; Chang, Shih-Wei; Jiangshieh, Ya-Fen; Tsai, Yu-Chuan; Lam, Chen-Fuh

    2011-01-01

    Renal blood flow (RBF) is tightly regulated by several intrinsic pathways in maintaining optimal kidney blood supply. Using a rat model of aortocaval (AC) fistula, we investigated remodeling of the renal artery following prolonged increased blood flow. An AC fistula was created in the infrarenal aorta of anesthetized rats, and changes of blood flow in the renal artery were assessed using an ultrasonic flow probe. Morphological changes and expression of endothelial nitric oxide synthase and matrix metalloproteinase-2 in the remodeled renal artery were analyzed. Blood flow in the renal artery increased immediately after creation of AC fistula, but normal RBF was restored 8 weeks later. The renal artery dilated significantly 8 weeks after operation. Expression of endothelial nitric oxide synthase and matrix metalloproteinase-2 was upregulated shortly after blood flow increase, and returned to baseline levels after 3 weeks. Histological sections showed luminal dilatation with medial thickening and endothelial cell-to-smooth muscle cell attachments in the remodeled renal artery. Increased RBF was accommodated by functional dilatation and remodeling in the medial layer of the renal artery in order to restore normal blood flow. Our results provide important mechanistic insight into the intrinsic regulation of the renal artery in response to increased RBF. Copyright © 2011 S. Karger AG, Basel.

  9. Doppler Flow Wire Evaluation of Renal Blood Flow Reserve in Hypertensive Patients with Normal Renal Arteries

    Beregi, Jean-Paul; Mounier-Vehier, Claire; Devos, Patrick; Gautier, Corinne; Libersa, Christian; McFadden, Eugene P.; Carre, Alain

    2000-01-01

    Purpose: To study the vasomotor responses of the renal microcirculation in patients with essential hypertension.Methods: We studied the reactivity of the renal microcirculation to papaverine, with intraarterial Doppler and quantitative arteriography, in 34 renal arteries of 19 hypertensive patients without significant renal artery stenosis. Isosorbide dinitrate was given to maximally dilate proximal renal arteries. APV (average peak blood flow velocity) was used as an index of renal blood flow.Results: Kidneys could be divided into two distinct subgroups based on their response to papaverine. An increase in APV of up to 55% occurred in 21 kidneys, an increase > 55% in 13 kidneys. Within each group the values were normally distributed. Both baseline APV and the effect of papaverine on mean velocity differed significantly between groups.Conclusion: There seems to be a subgroup of patients with essential hypertension that has an impaired reactivity to papaverine, consistent with a functional impairment of the renal microcirculation. Further studies are required to determine whether this abnormality contributes to or results from elevated blood pressure

  10. Middle cerebral artery flow velocity and blood flow during exercise and muscle ischemia in humans

    Jørgensen, L G; Perko, M; Hanel, B

    1992-01-01

    Changes in middle cerebral artery flow velocity (Vmean), measured by transcranial Doppler ultrasound, were used to determine whether increases in mean arterial pressure (MAP) or brain activation enhance cerebral perfusion during exercise. We also evaluated the role of "central command......, they support the hypothesis that cerebral perfusion during exercise reflects an increase in brain activation that is independent of MAP, central command, and muscle metaboreceptors but is likely to depend on influence of mechanoreceptors.......," mechanoreceptors, and/or muscle "metaboreceptors" on cerebral perfusion. Ten healthy subjects performed two levels of dynamic exercise corresponding to a heart rate of 110 (range 89-134) and 148 (129-170) beats/min, respectively, and exhaustive one-legged static knee extension. Measurements were continued during 2...

  11. Relationship of 133Xe cerebral blood flow to middle cerebral arterial flow velocity in men at rest

    Clark, J. M.; Skolnick, B. E.; Gelfand, R.; Farber, R. E.; Stierheim, M.; Stevens, W. C.; Beck, G. Jr; Lambertsen, C. J.

    1996-01-01

    Cerebral blood flow (CBF) was measured by 133Xe clearance simultaneously with the velocity of blood flow through the left middle cerebral artery (MCA) over a wide range of arterial PCO2 in eight normal men. Average arterial PCO2, which was varied by giving 4% and 6% CO2 in O2 and by controlled hyperventilation on O2, ranged from 25.3 to 49.9 mm Hg. Corresponding average values of global CBF15 were 27.2 and 65.0 ml 100 g min-1, respectively, whereas MCA blood-flow velocity ranged from 42.8 to 94.2 cm/s. The relationship of CBF to MCA blood-flow velocity over the imposed range of arterial PCO2 was described analytically by a parabola with the equation: CBF = 22.8 - 0.17 x velocity + 0.006 x velocity2 The observed data indicate that MCA blood-flow velocity is a useful index of CBF response to change in arterial PCO2 during O2 breathing at rest. With respect to baseline values measured while breathing 100% O2 spontaneously, percent changes in velocity were significantly smaller than corresponding percent changes in CBF at increased levels of arterial PCO2 and larger than CBF changes at the lower arterial PCO2. These observed relative changes are consistent with MCA vasodilation at the site of measurement during exposure to progressive hypercapnia and also during extreme hyperventilation hypocapnia.

  12. Relationship between retinal blood flow and arterial oxygen.

    Cheng, Richard W; Yusof, Firdaus; Tsui, Edmund; Jong, Monica; Duffin, James; Flanagan, John G; Fisher, Joseph A; Hudson, Chris

    2016-02-01

    Vascular reactivity, the response of the vessels to a vasoactive stimulus such as hypoxia and hyperoxia, can be used to assess the vascular range of adjustment in which the vessels are able to compensate for changes in PO2. Previous studies in the retina have not accurately quantified retinal vascular responses and precisely targeted multiple PaO2 stimuli at the same time as controlling the level of carbon dioxide, thus precluding them from modelling the relationship between retinal blood flow and oxygen. The present study modelled the relationship between retinal blood flow and PaO2, showing them to be a combined linear and hyperbolic function. This model demonstrates that the resting tonus of the vessels is at the mid-point and that they have great vascular range of adjustment, compensating for decreases in oxygen above a PETCO2 of 32-37 mmHg but being limited below this threshold. Retinal blood flow (RBF) increases in response to a reduction in oxygen (hypoxia) but decreases in response to increased oxygen (hyperoxia). However, the relationship between blood flow and the arterial partial pressure of oxygen has not been quantified and modelled in the retina, particularly in the vascular reserve and resting tonus of the vessels. The present study aimed to determine the limitations of the retinal vasculature by modelling the relationship between RBF and oxygen. Retinal vascular responses were measured in 13 subjects for eight different blood gas conditions, with the end-tidal partial pressure of oxygen (PETCO2) ranging from 40-500 mmHg. Retinal vascular response measurements were repeated twice; using the Canon laser blood flowmeter (Canon Inc., Tokyo, Japan) during the first visit and using Doppler spectral domain optical coherence tomography during the second visit. We determined that the relationship between RBF and PaO2 can be modelled as a combination of hyperbolic and linear functions. We concluded that RBF compensated for decreases in arterial oxygen content

  13. Clinical study of color Doppler sonography in Graves' disease blood flow changes after thyroid arteries embolization

    Zhuang Wenquan; Li Weiduo; Yang Jianyong; Chen Wei; Huang Yonghui; Guo Wenbo; Li Jiaping

    2003-01-01

    Objective: To study the color doppler image characteristics of thyroid arteries pre- and post-interventional procedure and to assess the clinical efficacy in Gnaves' disease. Methods: 11 from 31 patients diagnosed as Graves' disease undertaken thyroid arteries embolization, were analyzed. Color Doppler sonography was applied to monitor the pre-and post- procedure thyroid size and diameters of thyroid arteries. Power Doppler was used to detect the Vmax, Vmin, RI and blood flow. Results: After thyroid arteries embolization, the size and vascularity of thyroids were reduced. The thyroid arteries showed shrinkage and stoppage blood flow at the embolized site. The changes of RI, blood parameters of Vmax, Vmin and diameters of the thyroid arteries pre- and post-procedure turned out to be statistically significant for clinical restriction. Conclusion: The color Doppler sonography plays an important role for preoperative diagnosis and predicting the prognosis

  14. Blood flows in the maxillocarotid anastomoses and internal carotid artery of conscious dogs.

    Lee, M C; Reid, I A; Ramsay, D J

    1986-06-01

    Although the external carotid artery is known to contribute to the cerebral blood flow in anesthetized dogs, quantitative information on the anastomoses and their role in conscious dogs is lacking. This study was carried out to determine blood flows in these anastomoses and the internal carotid artery, and also to examine the functional significance of the anastomoses in conscious dogs. Fifteen-micron radioactive microspheres were injected into common and external carotid arteries of four conscious dogs through chronically implanted catheters. Blood flows were determined by the reference sample method and by comparing microsphere distributions in the brain and the masseter muscle. Blood flows were estimated to be 140 +/- 32, 7.7 +/- 1.4, and 3.3 +/- 1.1 ml/minute (mean +/- SD) in the common carotid artery, internal carotid artery, and anastomoses on each side, respectively. Additional evidence indicated that the anastomotic flow so determined was primarily the flow in the anastomotic artery. Humoral responses to angiotensin II infusions were also studied in conscious dogs. External carotid angiotensin increased plasma 11-hydroxycorticosteroid concentration (used as an index of ACTH secretion) but did not increase plasma vasopressin concentration to the same extent as common carotid infusion. Therefore, the external carotid artery is functionally important in perfusing the brain in conscious dogs.

  15. Axial flow velocity patterns in a normal human pulmonary artery model: pulsatile in vitro studies.

    Sung, H W; Yoganathan, A P

    1990-01-01

    It has been clinically observed that the flow velocity patterns in the pulmonary artery are directly modified by disease. The present study addresses the hypothesis that altered velocity patterns relate to the severity of various diseases in the pulmonary artery. This paper lays a foundation for that analysis by providing a detailed description of flow velocity patterns in the normal pulmonary artery, using flow visualization and laser Doppler anemometry techniques. The studies were conducted in an in vitro rigid model in a right heart pulse duplicator system. In the main pulmonary artery, a broad central flow field was observed throughout systole. The maximum axial velocity (150 cm s-1) was measured at peak systole. In the left pulmonary artery, the axial velocities were approximately evenly distributed in the perpendicular plane. However, in the bifurcation plane, they were slightly skewed toward the inner wall at peak systole and during the deceleration phase. In the right pulmonary artery, the axial velocity in the perpendicular plane had a very marked M-shaped profile at peak systole and during the deceleration phase, due to a pair of strong secondary flows. In the bifurcation plane, higher axial velocities were observed along the inner wall, while lower axial velocities were observed along the outer wall and in the center. Overall, relatively low levels of turbulence were observed in all the branches during systole. The maximum turbulence intensity measured was at the boundary of the broad central flow field in the main pulmonary artery at peak systole.

  16. Estimation of the flow resistances exerted in coronary arteries using a vessel length-based method.

    Lee, Kyung Eun; Kwon, Soon-Sung; Ji, Yoon Cheol; Shin, Eun-Seok; Choi, Jin-Ho; Kim, Sung Joon; Shim, Eun Bo

    2016-08-01

    Flow resistances exerted in the coronary arteries are the key parameters for the image-based computer simulation of coronary hemodynamics. The resistances depend on the anatomical characteristics of the coronary system. A simple and reliable estimation of the resistances is a compulsory procedure to compute the fractional flow reserve (FFR) of stenosed coronary arteries, an important clinical index of coronary artery disease. The cardiac muscle volume reconstructed from computed tomography (CT) images has been used to assess the resistance of the feeding coronary artery (muscle volume-based method). In this study, we estimate the flow resistances exerted in coronary arteries by using a novel method. Based on a physiological observation that longer coronary arteries have more daughter branches feeding a larger mass of cardiac muscle, the method measures the vessel lengths from coronary angiogram or CT images (vessel length-based method) and predicts the coronary flow resistances. The underlying equations are derived from the physiological relation among flow rate, resistance, and vessel length. To validate the present estimation method, we calculate the coronary flow division over coronary major arteries for 50 patients using the vessel length-based method as well as the muscle volume-based one. These results are compared with the direct measurements in a clinical study. Further proving the usefulness of the present method, we compute the coronary FFR from the images of optical coherence tomography.

  17. Ideal Internal Carotid Artery Trapping Technique without Bypass in a Patient with Insufficient Collateral Flow

    Chung, Joon Ho; Shin, Yong Sam; Lim, Yong Cheol; Park, Minjung

    2009-01-01

    Internal carotid artery (ICA) trapping can be used for treating intracranial giant aneurysm, blood blister-like aneurysms and ICA rupture during the surgery. We present a novel ICA trapping technique which can be used with insufficient collaterals flow via anterior communicating artery (AcoA) and posterior communicating artery (PcoA). A patient was admitted with severe headache and the cerebral angiography demonstrated a typical blood blister-like aneurysm at the contralateral side of PcoA. F...

  18. Associations between oral and ocular dryness, labial and whole salivary flow rates, systemic diseases and medications in a sample of older people

    Smidt, Dorte; Torpet, Lis Andersen; Nauntofte, Birgitte

    2011-01-01

    Abstract – Objective: To investigate the associations between age, gender, systemic diseases, medications, labial and whole salivary flow rates and oral and ocular dryness in older people. Methods: Symptoms of oral and ocular dryness, systemic diseases, medications (coded according...... number of diseases and medications, but neither with age and gender per se nor with tobacco and alcohol consumption. New detailed information concerning associations between medications and oral and ocular dryness has been obtained using the ATC classification system....... to the Anatomical therapeutic chemical (ATC) classification system), tobacco and alcohol consumption were registered, and unstimulated labial (LS) and unstimulated (UWS) and chewing-stimulated (SWS) whole salivary flow rates were measured in 668 randomly selected community-dwelling elderly aged 65–95. Results...

  19. 3D Heart Model and 4D Flow MRI 20 Years after Spiral Arterial Switch Operation.

    Sievers, Hans-Hinrich; Kheradvar, Arash; Kramer, Hans-Heiner; Rickers, Carsten

    2016-12-01

    Case of a patient is presented here 20 years after spiral direct anastomosis of the great arteries in an arterial switch operation. Three-dimensional model of the heart combined with four-dimensional flow magnetic resonance imaging presents a novel comprehensive way to assess surgical results.

  20. Measurement of blood flow in the carotid arteries using color doppler in healthy Korean adults

    Moon, Ki Ho; Jeon, Do Ig; Choi, Chang Ho; Ro, Young Jin; Kim, Hak Jin; Lee, Suck Hong; Kim, Byung Soo

    1994-01-01

    To evaluate the blood flow patterns and velocities of the carotid arteries in healthy Korean adults. We evaluated the blood flow patterns and measured the peak systolic and end-diastolic velocities of the common, internal and external carotid arteries in 48 healthy adults who did not have cardiovascular disorders and neck lesions. The velocity difference was analyzed according to different age groups. In addition, peak systolic and end-diastolic velocity ratio of the internal to common carotid artery was estimated, and our data were compared with values reported by other authors. Generally, the velocity in the younger age group tends be to higher than in older group. The peak systolic and end diastolic velocities of the internal carotid artery were 84.5 cm/sec and 30.5 cm/sec. The peak systolic and end diastolic velocity ratio of the internal to common carotid artery were 0.715 and 0.966. The internal carotid artery was less resistant in blood flow than the external carotid artery. Our data were lower than the values which were reported by Bluth et al. The blood flow velocities of the internal carotid artery in healthy adults were lower than those of previous reported foreign values, but the patterns were similar

  1. Ocular Complications Following Autologous Fat Injections into Facial Area: Case Report of a Recovery from Visual Loss After Ophthalmic Artery Occlusion and a Review of the Literature.

    Szantyr, Aleksandra; Orski, Michał; Marchewka, Ida; Szuta, Mariusz; Orska, Małgorzata; Zapała, Jan

    2017-06-01

    With the increase in popularity of the use of cosmetic fillers in plastic and esthetic surgery, the possibility of severe ocular complications should not be neglected. Of the fillers used, autologous fat is the most common to cause permanent visual deterioration, one of the most severe complications associated with the use of cosmetic fillers. Here we present the first report of a complete recovery of visual acuity from an instance of visual loss with no light perception caused by ophthalmic artery occlusion of the right eye following autologous fat injection in the facial area. Immediate ophthalmological intervention and comprehensive therapy with prostaglandins and vinpocetine made it possible to restore retinal perfusion and achieve complete recovery of visual acuity. Awareness of the iatrogenic artery occlusions associated with facial fillers and the need for immediate treatment should be popularized among injectors to prevent devastating consequences, such as permanent vision loss. Level of Evidence V This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

  2. Comparative study of Newtonian physiological blood flow through normal and stenosed carotid artery

    Rahman, Mohammad Matiur; Hossain, Md. Anwar; Mamun, Khairuzzaman; Akhter, Most. Nasrin

    2017-06-01

    A numerical simulation is performed to investigate Newtonian physiological flows behavior on three dimensional idealized carotid artery (CA) and single stenosed (75% by area) carotid artery(SCA). The wall vessel is set as rigid during simulation. Bifurcated blood vessel are simulated by using three-dimensional flow analysis. Physiological and parabolic velocity profiles are set out to fix the conditions of inlet boundaries of artery. In other hand, physiological waveform is an important part of compilation and it is successfully done by utilization of Fourier series having sixteen harmonics. The investigation has a Reynolds number range of 94 to 1120. Low Reynolds number k — ω model has been used as governing equation. The investigation has been carried out to characterize the flow behavior of blood in two geometry, namely, (i) Normal carotid artery (CA) and (ii) Stenosed carotid artery (SCA). The Newtonian model has been used to study the physics of fluid. The findings of the two models are thoroughly compared in order to observe there behavioral sequence of flows. The numerical results were presented in terms of velocity, pressure, wall shear stress distributions and cross sectional velocities as well as the streamlines contour. Stenosis disturbs the normal pattern of blood flow through the artery as reduced area. At stenosis region velocity and peak Reynolds number rapidly increase and Reynolds number reach transitional and turbulent region. These flow fluctuation and turbulence have bad effect to the blood vessel which makes to accelerate the progress of stenosis.

  3. Normal reference values for vertebral artery flow volume by color Doppler sonography in Korean adults

    Hong, Hyun Sook; Cha, Jang Gyu; Park, Seong Jin; Joh, Joon Hee; Park, Jai Soung; Kim, Dae Ho; Lee, Hae Kyung; Ahn, Hyun Cheol

    2003-01-01

    Vertebrobasilar ischemia has been attributed to a reduction of net vertebral artery flow volume. This study was to establish the reference values for the flow volume of the vertebral artery using color Doppler sonography in the normal Korea adults. Thirty five normal Korea adults without any underlying disease including hypertension, hyperlipidemia, diabetes, heart disease, obesity (body mas index>30), or carotid artery stenosis was included. There were 17 males and 18 females, age ranged from 20 to 53 years (average=32.86 years). Flow velocities and vessel diameters were recorded in the intertransverse (V2) segment, usually at C5-6 level, bilaterally. The flow volume (Q) was calculated. (Q=time averaged mean velocity x cross sectional area of vessel) A lower Flow velocity and smaller vessel diameter were measured on the right side compared to those of the left side, resulting in a lower flow volume. The calculated flow volumes using the equation were 77.0 ± 39.7 ml/min for the right side and 127.6 ± 71.0 ml/min for the left side (p=0.0001) while the net vertebral artery flow volume was 204.6 ± 81.8 ml/min. Decrease in the vertebral artery flow volume was statistically significant with advanced age. (r=-0.36, p=0.032). Vertebral artery blood flow volume was 191.20 ± 59.19 ml/min in male, and 217.28 ± 98.67 ml/min in female (p=0.6). The normal range for the net vertebral artery flow volume defined by the 5th to 95th percentiles was between 110.06 and 364.1 ml/min. The normal range for the net vertebral artery flow volume was between 110.06 and 364.1 ml/min. Vertebral artery flow volume decreased with the increase of age. However, gender did not affect the blood flow volume.

  4. Clinical observations on the effect of carotid artery occlusion on cerebral blood flow mapped by xenon computed tomography and its correlation with carotid artery back pressure

    Steed, D.L.; Webster, M.W.; DeVries, E.J.; Jungreis, C.A.; Horton, J.A.; Sehkar, L.; Yonas, H.

    1990-01-01

    Xenon computed tomographic cerebral blood flow mapping was correlated with internal carotid artery stump pressures and clinical neurologic assessment during temporary internal carotid artery occlusion. One hundred fourteen patients with skull base tumors or intracranial aneurysms potentially requiring carotid resection or ligation underwent angiography, xenon CT cerebral blood flow mapping, and internal carotid artery blood pressure monitoring. The internal carotid artery was then temporarily occluded with a balloon catheter, stump pressure was measured through the catheter, and the xenon CT cerebral blood flow mapping was repeated. Adequate xenon CT cerebral blood flow was defined as greater than 30 cc/100 gm/min. All patients had normal xenon CT cerebral blood flow before internal carotid artery occlusion. During internal carotid artery occlusion, xenon CT cerebral blood flow was found to be normal (group I, 40 patients), globally reduced but still within the normal range (group II, 50 patients), or low in the distribution of the ipsilateral middle cerebral artery (group III, 13 patients). With balloon occlusion, an immediate neurologic deficit developed in 11 patients (9%) requiring deflation of the balloon preceding xenon CT cerebral blood flow measurement (group IV). In group I internal carotid artery blood pressure was 128 mm Hg. (range 85 to 171 mm Hg) with stump pressure 86 mm Hg (range 46 to 125 mm Hg). In group II internal carotid artery blood pressure was 130 mm Hg. (range 78 to 199 mm Hg), with stump pressure 86 mm Hg (range 31 to 150 mm Hg)

  5. Investigation of spiral blood flow in a model of arterial stenosis

    Paul, M.C.; Larman, A.

    2009-01-01

    The spiral component of blood flow has both beneficial and detrimental effects in human circulatory system [Stonebridge PA, Brophy CM. Spiral laminar flow in arteries? Lancet 1991; 338: 1360–1]. We investigate the effects of the spiral blood flow in a model of three-dimensional arterial stenosis with a 75% cross-sectional area reduction at the centre by means of computational fluid dynamics (CFD) techniques. The standard κ–ω model is employed for simulation of the blood flow for the...

  6. Recirculation zone length in renal artery is affected by flow spirality and renal-to-aorta flow ratio.

    Javadzadegan, Ashkan; Fulker, David; Barber, Tracie

    2017-07-01

    Haemodynamic perturbations such as flow recirculation zones play a key role in progression and development of renal artery stenosis, which typically originate at the aorta-renal bifurcation. The spiral nature of aortic blood flow, division of aortic blood flow in renal artery as well as the exercise conditions have been shown to alter the haemodynamics in both positive and negative ways. This study focuses on the combinative effects of spiral component of blood flow, renal-to-aorta flow ratio and the exercise conditions on the size and distribution of recirculation zones in renal branches using computational fluid dynamics technique. Our findings show that the recirculation length was longest when the renal-to-aorta flow ratio was smallest. Spiral flow and exercise conditions were found to be effective in reducing the recirculation length in particular in small renal-to-aorta flow ratios. These results support the hypothesis that in renal arteries with small flow ratios where a stenosis is already developed an artificially induced spiral flow within the aorta may decelerate the progression of stenosis and thereby help preserve kidney function.

  7. Experimental study on representation of flow on the bifurcated carotid arterial phantoms using magnetic resonance angiography

    Chung, Tae Sub; Rhim, Yoon Chul; Kim, Kyung Oh; Suh, Sang Ho; Jin, En Hao

    1995-01-01

    A common finding of carotid artery on magnetic resonance angiograms(MRAs) is a signal dropout along the posterior wall of carotid bulb due to reverse flow. The purpose of this study is to evaluate variable flow patterns on bifurcated carotid arterial phantoms using steady-state flow. We designed phantoms of a bifurcated carotid artery with acrylic materials. Flow patterns were evaluated with axial and coronal imaging of MRA(2D-TOF, 3D-TOF), color Doppler imaging, and computational fluid dynamics (CFD) within the phantoms constructed of an automated closed-type circulatory system filled with 4% sugar solution. These findings were compared with findings obtained from normal volunteers. Axial 3D-TOF MRA images exhibited closer resemblance to the contour of the inner wall of phantoms when compared to coronal 2D-TOF MRA imaging. However, 2D-TOF MRA showed good contrast difference of signal intensities between forward flow area and reverse flow area. Dark zones with reduced signal intensities due to reversed flow were separated from the outer wall of the internal and external carotid arteries by a thin layer of forward flow along the wall on the source slice image of MRA. The general hemodynamics of the phantoms on MRA were identical to hemodynamics on color Doppler imaging and CFD. The results obtained with the phantoms matched the findings on normal volunteers. Although representations of bifurcated carotid arterial phantoms on axial 3D-TOF MRA were excellent if ideally designed, the zone of reversed flow could be a significant factor in creating distorted image when the zone of reversed flow contacted directly with curved or deformed arterial wall

  8. The relationship between fractional flow reserve, platelet reactivity and platelet leukocyte complexes in stable coronary artery disease

    Sels, J.W.E.M.; Rutten, B.; Holten, van T.C.; Hillaert, M.A.K.; Waltenberger, J.; Pijls, N.H.J.; Pasterkamp, G.; Groot, de P.G.; Roest, M.

    2013-01-01

    Background: The presence of stenoses that significantly impair blood flow and cause myocardial ischemia negatively affects prognosis of patients with stable coronary artery disease. Altered platelet reactivity has been associated with impaired prognosis of stable coronary artery disease. Platelets

  9. Impaired flow-induced arterial remodeling in DOCA-salt hypertensive rats

    Lemkens, Pieter; Nelissen, Jelly; Meens, Merlijn J P M T

    2012-01-01

    Arteries from young healthy animals respond to chronic changes in blood flow and blood pressure by structural remodeling. We tested whether the ability to respond to decreased (-90%) or increased (+100%) blood flow is impaired during the development of deoxycorticosterone acetate (DOCA)-salt hype...

  10. Abnormal arterial flows by a distributed model of the fetal circulation

    van den Wijngaard, Jeroen P. H. M.; Westerhof, Berend E.; Faber, Dirk J.; Ramsay, Margaret M.; Westerhof, Nico; van Gemert, Martin J. C.

    2006-01-01

    Modeling the propagation of blood pressure and flow along the fetoplacental arterial tree may improve interpretation of abnormal flow velocity waveforms in fetuses. The current models, however, either do not include a wide range of gestational ages or do not account for variation in anatomical,

  11. Fractional Flow Reserve Assessment of a Coronary Artery Fistula

    Joseph Petit

    2015-01-01

    Full Text Available A 63 y/o male with a past medical history of hypertension, chronic obstructive pulmonary disease, and obesity was admitted to an outside hospital for an abdominal incisional hernia repair and cholecystectomy. Post-operatively he developed shortness of breath (SOB and multiple runs of paroxysmal atrial fibrillation. A CT scan was negative for pulmonary embolism, but showed a left anterior descending (LAD coronary artery to main pulmonary artery (MPA fistula. He was transferred to our facility for further management.

  12. Ocular Melanoma

    ... is Ocular Melanoma? Leer en Español: ¿Qué es el melanoma ocular? Written By: Daniel Porter Reviewed By: Robert H Janigian Jr MD Sep. 01, 2017 Ocular melanoma (melanoma in or around the eye) is a type of cancer that develops in the cells that produce pigment. ...

  13. The PK-Eye: A Novel In Vitro Ocular Flow Model for Use in Preclinical Drug Development.

    Awwad, Sahar; Lockwood, Alastair; Brocchini, Steve; Khaw, Peng T

    2015-10-01

    A 2-compartment in vitro eye flow model has been developed to estimate ocular drug clearance by the anterior aqueous outflow pathway. The model is designed to accelerate the development of longer-acting ophthalmic therapeutics. Dye studies show aqueous flow is necessary for a molecule injected into the vitreous cavity to clear from the model. The clearance times of proteins can be estimated by collecting the aqueous outflow, which was first conducted with bevacizumab using phosphate-buffered saline in the vitreous cavity. A simulated vitreous solution was then used and ranibizumab (0.5 mg) displayed a clearance time of 8.1 ± 3.1 days, which is comparable to that observed in humans. The model can estimate drug release from implants or the dissolution of suspensions as a first step in their clearance mechanism, which will be the rate-limiting step for the overall resident time of a candidate dosage form in the vitreous. A suspension of triamcinolone acetonide (Kenalog®) (4.0 mg) displayed clearance times spanning 26-28 days. These results indicate that the model can be used to determine in vitro-in vivo correlations in preclinical studies to develop long-lasting therapeutics to treat blinding diseases at the back of the eye. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

  14. Comparison of Optic Nerve Head Blood Flow Autoregulation among Quadrants Induced by Decreased Ocular Perfusion Pressure during Vitrectomy

    Ryuya Hashimoto

    2017-01-01

    Full Text Available Purpose. The present study aimed to examine changes in optic nerve head (ONH blood flow autoregulation in 4 quadrants (superior, nasal, inferior, and temporal with decreased ocular perfusion pressure (OPP during vitrectomy in order to determine whether there is a significant difference of autoregulatory capacity in response to OPP decrease at each ONH quadrant. Methods. This study included 24 eyes with an epiretinal membrane or macular hole that underwent vitrectomy at Toho University Sakura Medical Center. Following vitrectomy, the tissue mean blur rate (MBR, which reflects ONH blood flow, was measured. Mean tissue MBRs in the four quadrants were generated automatically in the software analysis report. Measurements were conducted before and 5 and 10 min after intraocular pressure (IOP elevation of approximately 15 mmHg in the subjects without systemic disorders. Results. The baseline tissue MBR of the temporal quadrant was significantly lower than that of the other 3 quadrants (all P<0.05. However, the time courses of tissue MBR in response to OPP decrease were not significantly different among the four quadrants during vitrectomy (P=0.23. Conclusions. There is no significant difference in the autoregulatory capacity of the four ONH quadrants in patients without systemic disorders during vitrectomy.

  15. Additional value of B-flow imaging in arterial wall calcifications.

    D'Abate, Fabrizio; de Bruin, Jorg L

    2018-02-01

    The accuracy of color Doppler ultrasonography (CDU) is hampered by the presence of arterial wall calcifications. B-flow imaging may overcome these limitations. We present a case of a severely calcified stenosis of the right common femoral artery (CFA) diagnosed with the aid of B-flow imaging. Both the CT angiography scan and CDU were limited by the presence of diffuse dense arterial calcifications. B-flow imaging showed a >75% stenosis of the CFA. B-flow imaging appears to improve the accuracy of CDU in the presence of calcified stenosis of the CFA. It is of clinical relevance to improve the duplex sonographic accuracy, ideally reducing the need for other imaging modalities prior to surgery. © 2017 Wiley Periodicals, Inc. J Clin Ultrasound 46:136-139, 2018. © 2017 Wiley Periodicals, Inc.

  16. Diagnostic accuracy of color Doppler flow imaging and Duplex US in peripheral arterial disease

    Karmel, M.I.; Polak, J.F.; Whittemore, A.D.; Mannick, J.A.; Donaldson, M.C.; O'Leary, D.H.

    1988-01-01

    Color Doppler flow imaging (5 MHz) and Duplex US were used in a prospective examination of 154 arterial segments in the lower extremities of 11 symptomatic patients. Each extremity was divided into seven arterial segments (common femoral, profunda femoral, proximal, middle, and distal superficial femoral, and proximal and distal popliteal arteries). Arterial maps were drawn for each patient and compared with the arteriograms. Seventeen significant stenoses and 18 complete occlusions were predicted and confirmed by means of arteriography. Four significant stenoses and four occlusions were predicted and not confirmed. One hundred nine normal arterial segments were correctly predicted. No significant stenoses or occlusions were missed. Prospective identification of the severity and location of disease can help to optimize both the angiographic approach and hospital services utilization

  17. Enhancement of Arterial Pressure Pulsatility by Controlling Continuous-Flow Left Ventricular Assist Device Flow Rate in Mock Circulatory System.

    Bozkurt, Selim; van de Vosse, Frans N; Rutten, Marcel C M

    Continuous-flow left ventricular assist devices (CF-LVADs) generally operate at a constant speed, which reduces pulsatility in the arteries and may lead to complications such as functional changes in the vascular system, gastrointestinal bleeding, or both. The purpose of this study is to increase the arterial pulse pressure and pulsatility by controlling the CF-LVAD flow rate. A MicroMed DeBakey pump was used as the CF-LVAD. A model simulating the flow rate through the aortic valve was used as a reference model to drive the pump. A mock circulation containing two synchronized servomotor-operated piston pumps acting as left and right ventricles was used as a circulatory system. Proportional-integral control was used as the control method. First, the CF-LVAD was operated at a constant speed. With pulsatile-speed CF-LVAD assistance, the pump was driven such that the same mean pump output was generated. Continuous and pulsatile-speed CF-LVAD assistance provided the same mean arterial pressure and flow rate, while the index of pulsatility increased significantly for both arterial pressure and pump flow rate signals under pulsatile speed pump support. This study shows the possibility of improving the pulsatility of CF-LVAD support by regulating pump speed over a cardiac cycle without reducing the overall level of support.

  18. Renal hemodynamics: the influence of the renal artery ostium flow diverter

    Rossmann, Jenn Stroud; Albert, Scott; Balaban, Robert

    2013-11-01

    The recently identified renal artery ostium flow diverter may preferentially direct blood flow to the renal arteries, and may also influence flow patterns and recirculation known to be involved in atherogenesis. Three-dimensional computational fluid dynamics (CFD) simulations of steady and pulsatile blood flow are performed to investigate the influence of diverter size and position, and vascular geometry, on the flow patterns and fluid mechanical forces in the neighborhood of the diverter. CFD results show that the flow diverter does affect the blood distribution: depending on the diverter's position, the flow to the renal arteries may be increased or reduced. The results of simulations also show the diverter's effect on the Wall Shear Stress (WSS) distribution, and suggest that the diverter contributes to an atherogenic environment in the abdominal aorta, while being atheroprotective in the renal arteries themselves. These results support previous clinical findings, and suggest directions for further clinical study. The results of this work have direct implications in understanding the physiological significance of the diverter, and its potential role in the pathophysiological development of atherosclerosis.

  19. Collateral Flow and White Matter Disease in Patients with Internal Carotid Artery Occlusion.

    Ishikawa, Mami; Sugawara, Hitoshi; Nagai, Mutsumi; Kusaka, Gen; Tanaka, Yuichi; Naritaka, Heiji

    2017-01-01

    When an internal carotid artery (ICA) occludes, a patient may develop cerebral infarction (CI). We investigated whether CI caused by ICA occlusion (ICAO) is associated with collateral flow through the anterior and posterior communicating arteries (ACoA and PCoA). In 100 patients with ICAO, we investigated CI and white matter disease by performing an MRI and the anatomy of the ACoA and PCoA were investigated by performing magnetic resonance angiography. All patients were divided into the symptomatic CI group or the no-CI group. The collateral flow pathway was estimated by the anterior cerebral artery (ACA)-PCoA score and the collateral flow volume after ICAO was estimated by the middle cerebral artery (MCA) flow score, based on how well the MCA was visualized. Of 100 patients with ICAO, the symptomatic CI group included 36 patients. ACA-PCoA score and white matter disease grades were significantly higher in the CI group (indicating poor collateral flow). More than 80% of patients with an ACA-PCoA score of 4 (poor collateral) experienced symptomatic CI. Thirty-one symptomatic CI patients (86%) had an MCA flow score of 1 or 2 (decreased MCA flow). The ACA-PCoA score and white matter disease grade may suggest an increased risk of CI following ICAO. © 2016 S. Karger AG, Basel.

  20. Accuracy and Precision of a Plane Wave Vector Flow Imaging Method in the Healthy Carotid Artery

    Jensen, Jonas; Villagómez Hoyos, Carlos Armando; Traberg, Marie Sand

    2018-01-01

    The objective of the study described here was to investigate the accuracy and precision of a plane wave 2-D vector flow imaging (VFI) method in laminar and complex blood flow conditions in the healthy carotid artery. The approach was to study (i) the accuracy for complex flow by comparing...... of laminar flow in vivo. The precision in vivo was calculated as the mean standard deviation (SD) of estimates aligned to the heart cycle and was highest in the center of the common carotid artery (SD = 3.6% for velocity magnitudes and 4.5° for angles) and lowest in the external branch and for vortices (SD...... the velocity field from a computational fluid dynamics (CFD) simulation to VFI estimates obtained from the scan of an anthropomorphic flow phantom and from an in vivo scan; (ii) the accuracy for laminar unidirectional flow in vivo by comparing peak systolic velocities from VFI with magnetic resonance...

  1. Resting quantitative cerebral blood flow in schizophrenia measured by pulsed arterial spin labeling perfusion MRI

    Pinkham, Amy; Loughead, James; Ruparel, Kosha; Wu, Wen-Chau; Overton, Eve; Gur, Raquel; Gur, Ruben

    2011-01-01

    Arterial spin labeling imaging (ASL) perfusion MRI is a relatively novel technique that can allow for quantitative measurement of cerebral blood flow (CBF) by using magnetically labeled arterial blood water as an endogenous tracer. Available data on resting CBF in schizophrenia primarily comes from invasive and expensive nuclear medicine techniques that are often limited to small samples and yield mixed results. The noninvasive nature of ASL offers promise for larger-scale studies. The utilit...

  2. Evaluation of pulmonary artery flow in acute massive pulmonary thromboembolism with MRI

    Li Yongzhong; Li Kuncheng; Zhao Xigang; Zhao Hong

    2004-01-01

    Objective: To probe into the value of MR imaging in evaluating the pulmonary artery hemodynamics and pulmonary artery pressure in acute massive pulmonary embolism. Methods: MR studies were performed in 21 patients with acute massive pulmonary embolism (diagnosed by contrast enhanced MR pulmonary angiography) and 20 healthy volunteers. The pulmonary artery hemodynamic parameters, such as the diameters of main and right pulmonary artery, peak velocity, average velocity, flow volume, flow patterns, and ejection acceleration time in main pulmonary artery were measured. The findings in patients and volunteers were compared. The hemodynamic parameters in patients were correlated with mean pulmonary artery pressure acquired with right heart catheterization. Results: The diameters of main pulmonary artery (2.93 vs 2.52 cm) and right pulmonary artery (2.49 vs 1.92 cm) in patients and volunteers showed significant differences (t=3.55, P<0.01 and t=4.19, P<0.01, respectively); Peak velocity (85.29 vs 100.63 cm/s), average velocity (11.00 vs 17.12 cm/s), flow volume (89.15 vs 98.96 ml/s), and ejection acceleration time (105.09 vs 163.85 ms) in main pulmonary artery were significantly different between patients and volunteers (t values were 2.89, 6.37, 2.21, and 9.46, respectively; P values were 0.01, <0.01, 0.03, and <0.01, respectively). The peak velocity-time curve of main pulmonary artery acquired with velocity encoded cine of MR in patients demonstrated earlier and lower peak velocity as well as abnormal retrograde flow. In addition, linear correlations were seen between the mean pulmonary pressure and the diameter of main pulmonary artery (r=0.62, P=0.001), diameter of right pulmonary artery (r=0.63, P=0.001), and ejection acceleration time (r=-0.55, P=0.005). Conclusion: MR imaging is a promising technique not only for the detection of pulmonary thromboemboli but also for the evaluation of hemodynamic parameters in pulmonary hypertension. (author)

  3. Numerical investigation of MHD flow of blood and heat transfer in a stenosed arterial segment

    Majee, Sreeparna; Shit, G.C., E-mail: gcs@math.jdvu.ac.in

    2017-02-15

    A numerical investigation of unsteady flow of blood and heat transfer has been performed with an aim to provide better understanding of blood flow through arteries under stenotic condition. The blood is treated as Newtonian fluid and the arterial wall is considered to be rigid having deposition of plaque in its lumen. The heat transfer characteristic has been analyzed by taking into consideration of the dissipation of energy due to applied magnetic field and the viscosity of blood. The vorticity-stream function formulation has been adopted to solve the problem using implicit finite difference method by developing well known Peaceman–Rachford Alternating Direction Implicit (ADI) scheme. The quantitative profile analysis of velocity, temperature and wall shear stress as well as Nusselt number is carried out over the entire arterial segment. The streamline and temperature contours have been plotted to understand the flow pattern in the diseased artery, which alters significantly in the downstream of the stenosis in the presence of magnetic field. Both the wall shear stress and Nusselt number increases with increasing magnetic field strength. However, wall shear stress decreases and Nusselt number enhances with Reynolds number. The results show that with an increase in the magnetic field strength upto 8 T, does not causes any damage to the arterial wall, but the study is significant for assessing temperature rise during hyperthermic treatment. - Highlights: • Fully numerical simulation is carried out for MHD blood flow in stenosed artery. • Dissipation of energy due to both magnetic field and blood viscosity is considered. • Strong Vortices are observed at the downstream of the stenosis in the arterial wall. • Flow reversal of blood is reduced by applying sufficient magnetic field strength. • Isothermal lines are strongly distorted in the presence of magnetic field strength.

  4. Arterial Transit Time-corrected Renal Blood Flow Measurement with Pulsed Continuous Arterial Spin Labeling MR Imaging.

    Shimizu, Kazuhiro; Kosaka, Nobuyuki; Fujiwara, Yasuhiro; Matsuda, Tsuyoshi; Yamamoto, Tatsuya; Tsuchida, Tatsuro; Tsuchiyama, Katsuki; Oyama, Nobuyuki; Kimura, Hirohiko

    2017-01-10

    The importance of arterial transit time (ATT) correction for arterial spin labeling MRI has been well debated in neuroimaging, but it has not been well evaluated in renal imaging. The purpose of this study was to evaluate the feasibility of pulsed continuous arterial spin labeling (pcASL) MRI with multiple post-labeling delay (PLD) acquisition for measuring ATT-corrected renal blood flow (ATC-RBF). A total of 14 volunteers were categorized into younger (n = 8; mean age, 27.0 years) and older groups (n = 6; 64.8 years). Images of pcASL were obtained at three different PLDs (0.5, 1.0, and 1.5 s), and ATC-RBF and ATT were calculated using a single-compartment model. To validate ATC-RBF, a comparative study of effective renal plasma flow (ERPF) measured by 99m Tc-MAG3 scintigraphy was performed. ATC-RBF was corrected by kidney volume (ATC-cRBF) for comparison with ERPF. The younger group showed significantly higher ATC-RBF (157.68 ± 38.37 mL/min/100 g) and shorter ATT (961.33 ± 260.87 ms) than the older group (117.42 ± 24.03 mL/min/100 g and 1227.94 ± 226.51 ms, respectively; P renal ASL-MRI as debated in brain imaging.

  5. Twenty-four-hour exposure to altered blood flow modifies endothelial Ca2+-activated K+ channels in rat mesenteric arteries

    Hilgers, Rob H P; Janssen, Ger M J; Fazzi, Gregorio E

    2010-01-01

    We tested the hypothesis that changes in arterial blood flow modify the function of endothelial Ca2+-activated K+ channels [calcium-activated K+ channel (K(Ca)), small-conductance calcium-activated K+ channel (SK3), and intermediate calcium-activated K+ channel (IK1)] before arterial structural...... remodeling. In rats, mesenteric arteries were exposed to increased [+90%, high flow (HF)] or reduced blood flow [-90%, low flow (LF)] and analyzed 24 h later. There were no detectable changes in arterial structure or in expression level of endothelial nitric-oxide synthase, SK3, or IK1. Arterial relaxing...... arteries, the balance between the NO/prostanoid versus EDHF response was unaltered. However, the contribution of IK1 to the EDHF response was enhanced, as indicated by a larger effect of TRAM-34 and a larger residual NS309-induced relaxation in the presence of UCL 1684. Reduction of blood flow selectively...

  6. Unsteady Blood Flow with Nanoparticles Through Stenosed Arteries in the Presence of Periodic Body Acceleration

    Fatin Jamil, Dzuliana; Roslan, Rozaini; Abdulhameed, Mohammed; Che-Him, Norziha; Sufahani, Suliadi; Mohamad, Mahathir; Ghazali Kamardan, Muhamad

    2018-04-01

    The effects of nanoparticles such as Fe 3O4,TiO2, and Cu on blood flow inside a stenosed artery are studied. In this study, blood was modelled as non-Newtonian Bingham plastic fluid subjected to periodic body acceleration and slip velocity. The flow governing equations were solved analytically by using the perturbation method. By using the numerical approaches, the physiological parameters were analyzed, and the blood flow velocity distributions were generated graphically and discussed. From the flow results, the flow speed increases as slip velocity increases and decreases as the values of yield stress increases.

  7. A 2D nonlinear multiring model for blood flow in large elastic arteries

    Ghigo, Arthur R.; Fullana, Jose-Maria; Lagrée, Pierre-Yves

    2017-12-01

    In this paper, we propose a two-dimensional nonlinear ;multiring; model to compute blood flow in axisymmetric elastic arteries. This model is designed to overcome the numerical difficulties of three-dimensional fluid-structure interaction simulations of blood flow without using the over-simplifications necessary to obtain one-dimensional blood flow models. This multiring model is derived by integrating over concentric rings of fluid the simplified long-wave Navier-Stokes equations coupled to an elastic model of the arterial wall. The resulting system of balance laws provides a unified framework in which both the motion of the fluid and the displacement of the wall are dealt with simultaneously. The mathematical structure of the multiring model allows us to use a finite volume method that guarantees the conservation of mass and the positivity of the numerical solution and can deal with nonlinear flows and large deformations of the arterial wall. We show that the finite volume numerical solution of the multiring model provides at a reasonable computational cost an asymptotically valid description of blood flow velocity profiles and other averaged quantities (wall shear stress, flow rate, ...) in large elastic and quasi-rigid arteries. In particular, we validate the multiring model against well-known solutions such as the Womersley or the Poiseuille solutions as well as against steady boundary layer solutions in quasi-rigid constricted and expanded tubes.

  8. Spiral blood flows in an idealized 180-degree curved artery model

    Bulusu, Kartik V.; Kulkarni, Varun; Plesniak, Michael W.

    2017-11-01

    Understanding of cardiovascular flows has been greatly advanced by the Magnetic Resonance Velocimetry (MRV) technique and its potential for three-dimensional velocity encoding in regions of anatomic interest. The MRV experiments were performed on a 180-degree curved artery model using a Newtonian blood analog fluid at the Richard M. Lucas Center at Stanford University employing a 3 Tesla General Electric (Discovery 750 MRI system) whole body scanner with an eight-channel cardiac coil. Analysis in two regions of the model-artery was performed for flow with Womersley number=4.2. In the entrance region (or straight-inlet pipe) the unsteady pressure drop per unit length, in-plane vorticity and wall shear stress for the pulsatile, carotid artery-based flow rate waveform were calculated. Along the 180-degree curved pipe (curvature ratio =1/7) the near-wall vorticity and the stretching of the particle paths in the vorticity field are visualized. The resultant flow behavior in the idealized curved artery model is associated with parameters such as Dean number and Womersley number. Additionally, using length scales corresponding to the axial and secondary flow we attempt to understand the mechanisms leading to the formation of various structures observed during the pulsatile flow cycle. Supported by GW Center for Biomimetics and Bioinspired Engineering (COBRE), MRV measurements in collaboration with Prof. John K. Eaton and, Dr. Chris Elkins at Stanford University.

  9. Enhancement of arterial pressure pulsatility by controlling continuous-flow left ventricular assist device flow rate in mock circulatory system

    Bozkurt, S.; van de Vosse, F.N.; Rutten, M.C.M.

    Continuous-flow left ventricular assist devices (CF-LVADs) generally operate at a constant speed, which reduces pulsatility in the arteries and may lead to complications such as functional changes in the vascular system, gastrointestinal bleeding, or both. The purpose of this study is to increase

  10. Relationship between vertebral artery blood flow in different head positions and vertigo.

    Araz Server, Ela; Edizer, Deniz Tuna; Yiğit, Özgür; Yasak, Ahmet Görkem; Erdim, Çağrı

    2018-01-01

    To identify the vertebral artery blood flow in different head positions in patients with positional vertigo with no specific diagnosis. Patients with history of vestibular symptoms associated with changes in head position were enrolled into the study. Healthy volunteers were evaluated as control group. Doppler ultrasonography examination of the cervical segment of the vertebral arteries was performed under three different head positions: (i) supine position, (ii) head hyperextended and rotated to the right side and (iii) head hyperextended and rotated to the left side. In the study group, right and left vertebral artery blood flow was significantly lower in the ipsilateral hyperextended position compared to standard supine position (respectively p = .014; p = .001), but did not differ significantly when compared between the standard supine and contralateral hyperextended positions (respectively = .959; p = .669). In the control group, left and right vertebral artery blood flow did not differ significantly when the head was hyperextended to the right or left sides compared to standard supine position (p > .05). Our data demonstrated that the etiology of vestibular complaints in patients with undiagnosed positional vertigo might be related to impairment in vertebral artery blood flow according to head positions.

  11. Carotid Artery Stenting in a Patient With a Continuous-Flow Left Ventricular Assist Device.

    Piazza, Michele; Squizzato, Francesco; Grego, Franco; Bottio, Tommaso; Gerosa, Gino; Antonello, Michele

    2016-08-01

    To demonstrate the safety and feasibility of carotid artery stenting (CAS) in a patient with a continuous-flow left ventricular assist device (LVAD). A 54-year-old woman with a LVAD was referred for a 90% stenosis of the right internal carotid artery (ICA). The patient was offered CAS, and oral anticoagulant was not discontinued in the periprocedural period. Because of absent arterial pulses, percutaneous transfemoral access was obtained under ultrasound guidance. Particular attention was paid to cannulation of the innominate artery; a 7-F guiding catheter was advanced from the descending aorta into the innominate artery under road-mapping, avoiding maneuvers in the ascending aorta where the outflow Dacron graft of the LVAD was anastomosed. To avoid cerebral flow modifications, the Angioguard RX was used as the cerebral protection device rather than other devices such as the flow reversal or flow-clamping systems. At this point, CAS was performed in a standard fashion using the 7×30-mm Precise ProRX stent. The computed tomography angiogram at 6 months showed patency of the stented right ICA. With adequate planning, CAS appears feasible in patients with a LVAD. © The Author(s) 2016.

  12. Evaluation of the carotid artery stenosis based on minimization of mechanical energy loss of the blood flow.

    Sia, Sheau Fung; Zhao, Xihai; Li, Rui; Zhang, Yu; Chong, Winston; He, Le; Chen, Yu

    2016-11-01

    Internal carotid artery stenosis requires an accurate risk assessment for the prevention of stroke. Although the internal carotid artery area stenosis ratio at the common carotid artery bifurcation can be used as one of the diagnostic methods of internal carotid artery stenosis, the accuracy of results would still depend on the measurement techniques. The purpose of this study is to propose a novel method to estimate the effect of internal carotid artery stenosis on the blood flow based on the concept of minimization of energy loss. Eight internal carotid arteries from different medical centers were diagnosed as stenosed internal carotid arteries, as plaques were found at different locations on the vessel. A computational fluid dynamics solver was developed based on an open-source code (OpenFOAM) to test the flow ratio and energy loss of those stenosed internal carotid arteries. For comparison, a healthy internal carotid artery and an idealized internal carotid artery model have also been tested and compared with stenosed internal carotid artery in terms of flow ratio and energy loss. We found that at a given common carotid artery bifurcation, there must be a certain flow distribution in the internal carotid artery and external carotid artery, for which the total energy loss at the bifurcation is at a minimum; for a given common carotid artery flow rate, an irregular shaped plaque at the bifurcation constantly resulted in a large value of minimization of energy loss. Thus, minimization of energy loss can be used as an indicator for the estimation of internal carotid artery stenosis.

  13. Improved assessment of functional severity of coronary artery stenosis by analysis of combined intracoronary pressure and flow velocity signals

    Nolte, F.

    2014-01-01

    Coronary artery disease (CAD) accounts for almost 2 million deaths per year within the EU. CAD is often characterized by focal narrowing of epicardial arteries, limiting coronary arterial flow and myocardial perfusion. Treatment of critical lesions by percutaneous coronary intervention (PCI) can be

  14. Estimation of brachial artery volume flow by duplex ultrasound imaging predicts dialysis access maturation.

    Ko, Sae Hee; Bandyk, Dennis F; Hodgkiss-Harlow, Kelley D; Barleben, Andrew; Lane, John

    2015-06-01

    This study validated duplex ultrasound measurement of brachial artery volume flow (VF) as predictor of dialysis access flow maturation and successful hemodialysis. Duplex ultrasound was used to image upper extremity dialysis access anatomy and estimate access VF within 1 to 2 weeks of the procedure. Correlation of brachial artery VF with dialysis access conduit VF was performed using a standardized duplex testing protocol in 75 patients. The hemodynamic data were used to develop brachial artery flow velocity criteria (peak systolic velocity and end-diastolic velocity) predictive of three VF categories: low (800 mL/min). Brachial artery VF was then measured in 148 patients after a primary (n = 86) or revised (n = 62) upper extremity dialysis access procedure, and the VF category correlated with access maturation or need for revision before hemodialysis usage. Access maturation was conferred when brachial artery VF was >600 mL/min and conduit imaging indicated successful cannulation based on anatomic criteria of conduit diameter >5 mm and skin depth 800 mL/min was predicted when the brachial artery lumen diameter was >4.5 mm, peak systolic velocity was >150 cm/s, and the diastolic-to-systolic velocity ratio was >0.4. Brachial artery velocity spectra indicating VF 800 mL/min. Duplex testing to estimate brachial artery VF and assess the conduit for ease of cannulation can be performed in 5 minutes during the initial postoperative vascular clinic evaluation. Estimation of brachial artery VF using the duplex ultrasound, termed the "Fast, 5-min Dialysis Duplex Scan," facilitates patient evaluation after new or revised upper extremity dialysis access procedures. Brachial artery VF correlates with access VF measurements and has the advantage of being easier to perform and applicable for forearm and also arm dialysis access. When brachial artery velocity spectra criteria confirm a VF >800 mL/min, flow maturation and successful hemodialysis are predicted if anatomic criteria

  15. Radionuclide scanning in a study of the pulmonary blood flow with the open arterial canal

    Rizaev, M.N.; Gulyamov, D.S.; Khodzhibekov, M.Kh.; Anvarov, M.A.

    1980-01-01

    Characteristic features of the distribution of the arterial pulmonary blood flow have been studied in 32 patients with the open arterial flow by lung scanning with albumin macroaggregate and 131 I. Research was conducted using the gamma-Ochamber ''Fo Gamma LFV'' and the scanner ''Magnaskaner 500I''. Disordered distribution of the pulmonary blood flow expressed in its unilateral decrease was detected in 17 patients (52.9%). A higher frequency of pulmonary hypertension was noted in these patients versus those with a relatively normal distribution of the pulmonary blood flow. A severe course of the disease was observed in high pulmonary hypertension combined with sharp suppression of the blood flow in one of the lungs or with signs of the shift from the right to the left side

  16. Quantitative determination of pulmonary artery flow by scintiscanning in patients with mitral stenosis

    Carvalho, N.; Fujioka, T.; Dias Neto, A.; Papaleo Netto, M.

    1974-01-01

    In twenty-two patients with pure or predominant mitral stenosis, with pulmonary hypertension, the quantitative blood flow of the pulmonary artery systems through the distribution of macroaggregated radio-iodinated ( 131 I) albumin is studied, by pulmonary digital scanning. Through the relations ship between the radioactive concentration in each organ, it is possible to classify three types of images: normal, balanced and inverted. This technique is useful for quantitative analysis of pulmonary artery flow, as a test that should preced cardiac catheterization and in the follow-up of the surgical results [pt

  17. Haemodynamic study of Flow in concentric and eccentric stenosed carotid Artery

    Khader S. M. Abdul

    2018-01-01

    Full Text Available Study of flow through arteries is gaining importance in the recent times due to onset of several cardio-vascular diseases like atherosclerosis (block in artery, aneurysms (bulging of artery, hypertension etc. The application of CFD will be useful in demonstrating the underlying mechanism of flow past the diseased arteries. In the present study, initially an approximate eccentric and concentric 50% stenosed carotid model is generated in ANSYS 12.0 based on patient data obtained from ultrasound Doppler scan. Later the percentage of stenosis is increased to 60%, 70%, 80% and 90% in both the cases. A transient analysis has been performed for several pulse cycles in ANSYS FLOTRAN for various percentage cases. The results obtained from ECN and CCN cases are compared to observe the changes in flow behavior in the downstream of stenosis as compared with normal case. The formation of vortices and flow separation zone in downstream in eccentric case is higher than in concentric case. Comparison of results concludes that, with the increase in severity of stenosis, the flow changes abruptly causing an increase in velocity and WSS at throat region. The simulation results obtained agree well with clinically observed data and available literature.

  18. Numerical investigation of MHD flow of blood and heat transfer in a stenosed arterial segment

    Majee, Sreeparna; Shit, G. C.

    2017-02-01

    A numerical investigation of unsteady flow of blood and heat transfer has been performed with an aim to provide better understanding of blood flow through arteries under stenotic condition. The blood is treated as Newtonian fluid and the arterial wall is considered to be rigid having deposition of plaque in its lumen. The heat transfer characteristic has been analyzed by taking into consideration of the dissipation of energy due to applied magnetic field and the viscosity of blood. The vorticity-stream function formulation has been adopted to solve the problem using implicit finite difference method by developing well known Peaceman-Rachford Alternating Direction Implicit (ADI) scheme. The quantitative profile analysis of velocity, temperature and wall shear stress as well as Nusselt number is carried out over the entire arterial segment. The streamline and temperature contours have been plotted to understand the flow pattern in the diseased artery, which alters significantly in the downstream of the stenosis in the presence of magnetic field. Both the wall shear stress and Nusselt number increases with increasing magnetic field strength. However, wall shear stress decreases and Nusselt number enhances with Reynolds number. The results show that with an increase in the magnetic field strength upto 8 T, does not causes any damage to the arterial wall, but the study is significant for assessing temperature rise during hyperthermic treatment.

  19. Analysis of the flow in stenosed carotid artery bifurcation models--hydrogen-bubble visualisation.

    Palmen, D E; van de Vosse, F N; Janssen, J D; van Dongen, M E

    1994-05-01

    This paper deals with the effect of geometric changes of mild stenoses on large-scale flow disturbances in the carotid artery bifurcation. Hydrogen-bubble visualisation experiments have been performed in Plexiglas models of a non-stenosed and a 25% stenosed carotid artery bifurcation. The flow conditions approximate physiological flow. The experiments show that shortly after the onset of the diastolic phase vortex formation occurs in the plane of symmetry. This vortex formation is found in a shear layer, which is formed in the carotid sinus. The shear layer is located between a region with low shear rates at the non-divider wall and a region with high shear rates at the divider wall. In order to gain insight into the parameters that are important with respect to the stability of the shear layer, experiments have been performed in which the influence of the shape of the flow pulse, the Reynolds number (Re), the Womersley parameter (alpha) and the flow division ratio (gamma) on the flow phenomena is studied. From these experiments it appears that the flow phenomena in the carotid artery bifurcation are significantly influenced by Re, alpha the systolic acceleration (sa) and deceleration (sd) and the duration of the peak-systolic flow (Tmax). With these results a simplified flow pulse is chosen, with which the experiments in the non-stenosed and the 25% stenosed bifurcation are performed. Comparison of the hydrogen-bubble profiles in the 0 and 25% stenosed models with similar flow conditions shows that the geometric change of the 25% stenosis only slightly influences the flow phenomena. The most striking influences are found in the stability of the shear layer. Quantitative experiments by means of laser Doppler anemometry measurements and numerical computations are needed to analyse the influence of the stenosis of the flow field more accurately.

  20. Investigation of spiral blood flow in a model of arterial stenosis.

    Paul, Manosh C; Larman, Arkaitz

    2009-11-01

    The spiral component of blood flow has both beneficial and detrimental effects in human circulatory system [Stonebridge PA, Brophy CM. Spiral laminar flow in arteries? Lancet 1991; 338: 1360-1]. We investigate the effects of the spiral blood flow in a model of three-dimensional arterial stenosis with a 75% cross-sectional area reduction at the centre by means of computational fluid dynamics (CFD) techniques. The standard k-omega model is employed for simulation of the blood flow for the Reynolds number of 500 and 1000. We find that for Re=500 the spiral component of the blood flow increases both the total pressure and velocity of the blood, and some significant differences are found between the wall shear stresses of the spiral and non-spiral induced flow downstream of the stenosis. The turbulent kinetic energy is reduced by the spiral flow as it induces the rotational stabilities in the forward flow. For Re=1000 the tangential component of the blood velocity is most influenced by the spiral speed, but the effect of the spiral flow on the centreline turbulent kinetic energy and shear stress is mild. The results of the effects of the spiral flow are discussed in the paper along with the relevant pathological issues.

  1. Vasoactive enzymes and blood flow responses to passive and active exercise in peripheral arterial disease

    Walker, Meegan A.; Høier, Birgitte; Walker, Philip J.

    2016-01-01

    Background: Peripheral arterial disease (PAD) is characterised by impaired leg blood flow, which contributes to claudication and reduced exercise capacity. This study investigated to what extent vasoactive enzymes might contribute to altered blood flow in PAD (Fontaine stage II). Methods: We...... compared femoral artery blood flow during reactive hyperaemia, leg-extension exercise and passive leg movement, and determined the level of vasoactive enzymes in skeletal muscle samples from the vastus lateralis in PAD (n = 10, 68.5 ± 6.5 years) and healthy controls (CON, n = 9, 62.1 ± 12.3 years). Leg...... than CON (1.04 ± 0.19 vs 0.50 ± 0.06 AU, P = 0.02), with no differences for other enzymes. Leg blood flow during exercise was correlated with prostacyclin synthase (P = 0.001). Conclusion: Elevated NADPH oxidase indicates that oxidative stress may be a primary cause of low nitric oxide availability...

  2. External carotid artery flow maintains near infrared spectroscopy-determined frontal lobe oxygenation during ephedrine administration

    Sørensen, H; Rasmussen, P; Sato, K

    2014-01-01

    O₂ by 10.5 (8.2-12.9%; Padministration of ephedrine while SinvosO₂ and SavO₂ decreased [by 3.1 (0.7-4.5%; P=0.017) and 2.1 (0.5-3.3%; P=0.......012)] as arterial carbon dioxide pressure decreased (P=0.003). ICAf was stable and ECAf increased by 11 (4-18%; P=0.005) with administration of ephedrine while SskinO₂ did not change. CONCLUSIONS: The effect of phenylephrine on ScO₂ is governed by a decrease in external carotid blood flow since it increases...... cerebral blood flow as determined by flow in the internal carotid artery. In contrast, ScO₂ is largely maintained with administration of ephedrine because blood flow to extracerebral tissue increases....

  3. A Short Introduction to Arterial Spin Labeling and its Application to Flow Territory Mapping.

    Lindner, T; Helle, M; Jansen, O

    2015-10-01

    Arterial spin labeling (ASL) is an emerging method for the assessment of perfusion in various diseases of the brain. In ASL, the magnetization of arterial blood water spins is manipulated in a complete non-invasive way before flowing into the tissue of interest. This allows absolute quantification of cerebral blood flow, thereby, presenting an alternative to contrast-enhanced methods based on computed tomography or magnetic resonance imaging. Furthermore, its potential application for flow territory mapping can provide additional information of the individual configuration of intracerebral blood flow. This article gives a brief overview of the basic ASL methodology and its approaches to image individual perfusion territories. Additionally, the utilization of ASL in a variety of cerebrovascular diseases is presented to provide examples of potential applications of (territorial) ASL in clinical routine.

  4. Continuous stroke volume monitoring by modelling flow from non-invasive measurement of arterial pressure in humans under orthostatic stress

    Harms, M.P.M.; Wesseling, K.H.; Pott, F.; Jenstrup, M.; Goudoever, J. van; Secher, N.H.; Lieshout, J.J. van

    1999-01-01

    The relationship between aortic flow and pressure is described by a three-element model of the arterial input impedance, including continuous correction for variations in the diameter and the compliance of the aorta (Modelflow). We computed the aortic flow from arterial pressure by this model, and

  5. Changes in cerebral artery blood flow velocity after intermittent cerebrospinal fluid drainage.

    Kempley, S T; Gamsu, H R

    1993-01-01

    Doppler ultrasound was used to measure blood flow velocity in the anterior cerebral artery of six premature infants with posthaemorrhagic hydrocephalus, before and after intermittent cerebrospinal fluid (CSF) drainage, on 23 occasions. There was a significant increase in mean blood flow velocity after the drainage procedures (+5.6 cm/s, 95% confidence interval +2.9 to +8.3 cm/s), which was accompanied by a decrease in velocity waveform pulsatility. CSF pressure also fell significantly. In pat...

  6. Dependence of renal blood flow on renal artery stenosis measured using CT angiography

    Luedemann, Lutz [Charite - Universitaetsmedizin Berlin (Germany). Dept. of Radiotherapy; Nafz, B.; Persson, P. [Charite - Universitaetsmedizin Berlin (Germany). Inst. for Vegetative Physiology; Elsner, F. [Krankenhaus am Urban, Berlin (Germany). Dept. of Anesthesiology; Grosse-Siestrup, C.; Meissler, M. [Charite - Universitaetsmedizin Berlin (Germany). Experimental Animal Unit; Gutberlet, M. [Charite - Universitaetsmedizin Berlin (Germany). Dept. of Diagnostic and Interventional Radiology; Univ. Leipzig/ Leipzig Heart Center (Germany). Dept. of Diagnostic and Interventional Radiology; Lengsfeld, P.; Voth, M. [Bayer-Schering Pharma AG, Berlin (Germany). Global Medical Affairs Diagnostic Imaging

    2011-03-15

    The present study investigates the suitability of computed tomography angiography (CTA) depicting the degree of renal artery stenosis for estimating renal blood flow (RBF) in a kidney. Materials and Methods: We investigated renal artery stenosis assessment by CTA in eight adult female hybrid pigs with an ultrasound probe implanted at the renal vein for RBF measurement. An inflatable metal-free cuff was placed around the renal artery to control the RBF. The RBF was then reduced in four steps. For each reduced RBF value and baseline RBF, CTA with a reconstructed slice thickness of 0.625 mm was performed in the arterial phase following injection of 80 ml of nonionic intravenous contrast medium. The radius of the stenotic and non-stenotic renal artery segment was measured in the reconstructed images. Results: A significant linear correlation (p < 0.0001) was found between the relative apparent stenosis (calculated as the ratio of the radii of the actual stenotic segment and a non-stenotic renal artery segment) and RBF. The linear regression yielded a slope of 0.57 and a y-axis of 24.1 %. A significant linear correlation (p < 0.0001) was also found between the relative true stenosis (the ratio of the radii of the actual stenotic segment and a non-stenotic renal artery segment at baseline) and the RBF. The linear regression yielded a slope of 0.67 and a y-axis of 13.8 %. Conclusion: The results show that the relative stenosis apparent on CTA differs from the true degree of renal artery stenosis. Nevertheless, the degree of renal artery stenosis determined by CTA provides a reliable estimate of the resulting RBF reduction. (orig.)

  7. Dependence of renal blood flow on renal artery stenosis measured using CT angiography

    Luedemann, Lutz; Nafz, B.; Persson, P.; Elsner, F.; Grosse-Siestrup, C.; Meissler, M.; Gutberlet, M.; Univ. Leipzig/ Leipzig Heart Center; Lengsfeld, P.; Voth, M.

    2011-01-01

    The present study investigates the suitability of computed tomography angiography (CTA) depicting the degree of renal artery stenosis for estimating renal blood flow (RBF) in a kidney. Materials and Methods: We investigated renal artery stenosis assessment by CTA in eight adult female hybrid pigs with an ultrasound probe implanted at the renal vein for RBF measurement. An inflatable metal-free cuff was placed around the renal artery to control the RBF. The RBF was then reduced in four steps. For each reduced RBF value and baseline RBF, CTA with a reconstructed slice thickness of 0.625 mm was performed in the arterial phase following injection of 80 ml of nonionic intravenous contrast medium. The radius of the stenotic and non-stenotic renal artery segment was measured in the reconstructed images. Results: A significant linear correlation (p < 0.0001) was found between the relative apparent stenosis (calculated as the ratio of the radii of the actual stenotic segment and a non-stenotic renal artery segment) and RBF. The linear regression yielded a slope of 0.57 and a y-axis of 24.1 %. A significant linear correlation (p < 0.0001) was also found between the relative true stenosis (the ratio of the radii of the actual stenotic segment and a non-stenotic renal artery segment at baseline) and the RBF. The linear regression yielded a slope of 0.67 and a y-axis of 13.8 %. Conclusion: The results show that the relative stenosis apparent on CTA differs from the true degree of renal artery stenosis. Nevertheless, the degree of renal artery stenosis determined by CTA provides a reliable estimate of the resulting RBF reduction. (orig.)

  8. Renal artery blood flow assessed by video dilution technique before and after percutaneous transluminal angioplasty

    Lantz, B.M.T.; Link, D.P.; Lewis, E.L.; Foerster, J.M.; Lee, G.

    1981-01-01

    Successful percutaneous transluminal angioplasty was performed in 3 cases of renal artery stenosis where the effect upon renal blood flow was quantified by video dilution technique. This technique adds important information to pressure gradients and renin assays obtained during the dilatation procedure. (Auth.)

  9. The clinical use of objective quantification of flow disturbance in carotid artery disease

    Sillesen, H; Bitsch, K; Steenberg, H J

    1987-01-01

    In order to assess the accuracy of objective quantification of carotid flow disturbance, 147 carotid arteries were examined with continuous wave (CW) Doppler technique. The systolic spectral broadening index (SBI), determined as (maximum-mean)/maximum frequency, was calculated from the power...

  10. Noninvasive arterial blood pressure waveforms in patients with continuous-flow left ventricular assist devices

    Martina, Jerson R.; Westerhof, Berend E.; de Jonge, Nicolaas; van Goudoever, Jeroen; Westers, Paul; Chamuleau, Steven; van Dijk, Diederik; Rodermans, Ben F. M.; de Mol, Bas A. J. M.; Lahpor, Jaap R.

    2014-01-01

    Arterial blood pressure and echocardiography may provide useful physiological information regarding cardiac support in patients with continuous-flow left ventricular assist devices (cf-LVADs). We investigated the accuracy and characteristics of noninvasive blood pressure during cf-LVAD support.

  11. Two-Fluid Mathematical Models for Blood Flow in Stenosed Arteries: A Comparative Study

    Sankar DS

    2009-01-01

    Full Text Available The pulsatile flow of blood through stenosed arteries is analyzed by assuming the blood as a two-fluid model with the suspension of all the erythrocytes in the core region as a non-Newtonian fluid and the plasma in the peripheral layer as a Newtonian fluid. The non-Newtonian fluid in the core region of the artery is assumed as a (i Herschel-Bulkley fluid and (ii Casson fluid. Perturbation method is used to solve the resulting system of non-linear partial differential equations. Expressions for various flow quantities are obtained for the two-fluid Casson model. Expressions of the flow quantities obtained by Sankar and Lee (2006 for the two-fluid Herschel-Bulkley model are used to get the data for comparison. It is found that the plug flow velocity and velocity distribution of the two-fluid Casson model are considerably higher than those of the two-fluid Herschel-Bulkley model. It is also observed that the pressure drop, plug core radius, wall shear stress and the resistance to flow are significantly very low for the two-fluid Casson model than those of the two-fluid Herschel-Bulkley model. Hence, the two-fluid Casson model would be more useful than the two-fluid Herschel-Bulkley model to analyze the blood flow through stenosed arteries.

  12. Can flavonoid-rich chocolate modulate arterial elasticity and pathological uterine artery Doppler blood flow in pregnant women? A pilot study.

    von Wowern, Emma; Olofsson, Per

    2018-09-01

    Dark chocolate has shown beneficial effects on cardiovascular health and might also modulate hypertensive complications in pregnancy and uteroplacental blood flow. Increased uteroplacental resistance is associated with systemic arterial stiffness. We aimed to investigate the short-term effect of flavonoid-rich chocolate on arterial stiffness and Doppler blood flow velocimetry indexes in pregnant women with compromised uteroplacental blood flow. Doppler blood flow velocimetry and digital pulse wave analysis (DPA) were performed in 25 women pregnant in the second and third trimesters with uterine artery (UtA) score (UAS) 3-4, before and after 3 days of ingestion of chocolate with high flavonoid and antioxidant contents. UtA pulsatility index (PI), UtA diastolic notching, UAS (semiquantitative measure of PI and notching combined), and umbilical artery PI were calculated, and DPA variables representing central and peripheral maternal arteries were recorded. Mean UtA PI (p = .049) and UAS (p = .025) significantly decreased after chocolate consumption. There were no significant changes in UtA diastolic notching or any DPA indexes of arterial stiffness/vascular tone. Chocolate may have beneficial effects on the uteroplacental circulation, but in this pilot study, we could not demonstrate effects on arterial vascular tone as assessed by DPA.

  13. An effective fractal-tree closure model for simulating blood flow in large arterial networks.

    Perdikaris, Paris; Grinberg, Leopold; Karniadakis, George Em

    2015-06-01

    The aim of the present work is to address the closure problem for hemodynamic simulations by developing a flexible and effective model that accurately distributes flow in the downstream vasculature and can stably provide a physiological pressure outflow boundary condition. To achieve this goal, we model blood flow in the sub-pixel vasculature by using a non-linear 1D model in self-similar networks of compliant arteries that mimic the structure and hierarchy of vessels in the meso-vascular regime (radii [Formula: see text]). We introduce a variable vessel length-to-radius ratio for small arteries and arterioles, while also addressing non-Newtonian blood rheology and arterial wall viscoelasticity effects in small arteries and arterioles. This methodology aims to overcome substantial cut-off radius sensitivities, typically arising in structured tree and linearized impedance models. The proposed model is not sensitive to outflow boundary conditions applied at the end points of the fractal network, and thus does not require calibration of resistance/capacitance parameters typically required for outflow conditions. The proposed model convergences to a periodic state in two cardiac cycles even when started from zero-flow initial conditions. The resulting fractal-trees typically consist of thousands to millions of arteries, posing the need for efficient parallel algorithms. To this end, we have scaled up a Discontinuous Galerkin solver that utilizes the MPI/OpenMP hybrid programming paradigm to thousands of computer cores, and can simulate blood flow in networks of millions of arterial segments at the rate of one cycle per 5 min. The proposed model has been extensively tested on a large and complex cranial network with 50 parent, patient-specific arteries and 21 outlets to which fractal trees where attached, resulting to a network of up to 4,392,484 vessels in total, and a detailed network of the arm with 276 parent arteries and 103 outlets (a total of 702,188 vessels

  14. Evaluation of arterial digital blood flow using Doppler ultrasonography in healthy dairy cows.

    Müller, H; Heinrich, M; Mielenz, N; Reese, S; Steiner, A; Starke, A

    2017-06-06

    Local circulatory disturbances have been implicated in the development of foot disorders in cattle. The goals of this study were to evaluate the suitability of the interdigital artery in the pastern region in both hind limbs using pulsed-wave (PW) Doppler ultrasonography and to investigate quantitative arterial blood flow variables at that site in dairy cows. An Esaote MyLabOne ultrasound machine with a 10-MHz linear transducer was used to assess blood flow in the interdigital artery in the pastern region in both hind limbs of 22 healthy German Holstein cows. The cows originated from three commercial farms and were restrained in a standing hoof trimming chute without sedation. A PW Doppler signal suitable for analysis was obtained in 17 of 22 cows. The blood flow profiles were categorised into four curve types, and the following quantitative variables were measured in three uniform cardiac cycles: vessel diameter, pulse rate, maximum systolic velocity, maximum diastolic velocity, end-diastolic velocity, reverse velocity, maximum time-averaged mean velocity, blood flow rate, resistance index and persistence index. The measurements did not differ among cows from the three farms. Maximum systolic velocity, vessel diameter and pulse rate did not differ but other variables differed significantly among blood flow profiles. Differences in weight-bearing are thought to be responsible for the normal variability of blood flow profiles in healthy cows. The scanning technique used in this report for evaluation of blood flow in the interdigital artery appears suitable for further investigations in healthy and in lame cows.

  15. Value of downstream circulation in renal artery stenosis with arterial hypertension: comparison between color Doppler flow and digital renal angiography in 123 patients

    Grataloup, C.; Challande, P.; Plainfosse, M.C.; Girerd, X.; Belattar, K.; Plouin, P.F.

    1996-01-01

    Digital renal angiography and color Doppler flow were compared for diagnosis of renal artery stenosis in 123 hypertensive patients with a prevalence of renal artery stenosis ≥75% of 21 %. Only color Doppler flow signs found downstream from the stenosis could be quantified. A rising time (RT) >0.07 s was the best marker for renal artery stenosis ≥ 75 % according to a receiver operating characteristic curve with a specificity of 97 %, a sensitivity of 88 %, a positive predictive value of 86 %, a negative predictive value of 98 % and an accuracy of 96 %. Digital renal angiography and color Doppler flow findings for renal artery lesions were classified into 4 degrees with agreement for 86 % of the kidneys. (authors). 13 refs., 5 figs., 8 tabs

  16. Renovascular hypertension due to insufficient collateral flow in segmental artery occulusion

    Park, Y. H.; Lee, S. Y.; Kim, S. H.; Sohn, H. S.; Chung, S. K.

    2001-01-01

    We report a case in which a 33-year-old woman with renovascular hypertension due to insufficient collateral flow in segmental renal artery occlusion demonstrated abnormality on captopril renal scintigram. Baseline renal scintigram with DTPA showed normal perfusion and excretion in left kidney and captopril renal scintigram with DTPA showed a focal area of decreased perfusion and delayed clearance in lower half of left kidney, suggesting segmental renal artery stenosis. Selective left renal arteriography showed complete obstruction in proximal portion of anterior segmental artery with multiple small collateral vessels from posterior segmental artery and capsular artery and delayed opacification in lower half of left kidney. These findings are suggestive of segmental hypoperfusion due to insufficient collateral blood flow resulting to positive captopril response. Patient's blood pressure have been controlled well with ACE (angiotensin converting enzyme) inhibitor and calcium channel blocker for 2 year. Follow-up baseline renal scintigram with MAG3 showed normal perfusion and excretion in left kidney and captopril renal scintigram with MAG3 showed a focal area of decreased perfusion and delayed clearance in lower lateral portion of left kidney, which was smaller size than that of previous renal scintigram. And captopril renal scintigram with DMSA demonstrated a small area of decreased DMSA uptake on this lesion compared to baseline DMSA scintigram

  17. Effect of hypertensive disorders during pregnancy on neonatal outcomes and umbilical artery flow

    Dong-mei ZHENG

    2013-09-01

    Full Text Available Objective To observe the effect of hypertensive disorders during pregnancy (HDP on neonatal outcomes and umbilical artery flow. Methods A prospective cohort study method was employed, and 60 pregnant women met the HDP diagnostic criteria (HDP group, aged 31.2±6.0 years, gestation time 251.0±9.0d, hospitalized from Sep. 2011 to May. 2012, and delivered live-born infants and 63 pregnant women with normal blood pressure and without medical or surgical ailments (control group, aged 30.2±2.8 years, gestation time 251.9±7.7d, hospitalized in the the same period, and had live birth were involved in present study. The indexes of umbilical artery blood flow were measured, the adverse neonatal outcomes (neonatal asphyxia, low birth weight babies and premature labor were recorded, and the correlation was analyzed between the adverse neonatal outcomes and the indexes of umbilical artery blood flow. Results The incidence of adverse neonatal outcomes (neonatal asphyxia, low birth weight newborns and premature labor was higher in HDP group (58.3%, 45.0% and 53.3%, respectively than in control group (6.3%, 3.2% and 3.2%, respectively, P<0.05. The results of umbilical artery blood flow indexes, including pulsatility index (PI, resistance index (RI and systolic/diastolic ratio (S/D in HDP group (0.897±0.176, 0.588±0.701 and 2.655±0.346, respectively were significantly higher than in control group (0.741±0.123, 0.525±0.650 and 2.120±0.364, respectively, P<0.05. The indexes of umbilical artery blood flow (PI, RI and S/D in newborns with adverse outcomes were significantly higher than in those newborn without adverse outcomes. Multivariate logistic regression revealed a positive correlation between RI and adverse neonatal outcomes. Conclusions The indexes of umbilical artery blood flow appear to be abnormal in pregnant women with HDP, and adverse neonatal conditions (neonatal asphyxia, low birth weight newborns and premature labor are prone to

  18. Pulsatility of Lenticulostriate Arteries Assessed by 7 Tesla Flow MRI-Measurement, Reproducibility, and Applicability to Aging Effect.

    Schnerr, Roald S; Jansen, Jacobus F A; Uludag, Kamil; Hofman, Paul A M; Wildberger, Joachim E; van Oostenbrugge, Robert J; Backes, Walter H

    2017-01-01

    Characterization of flow properties in cerebral arteries with 1.5 and 3 Tesla MRI is usually limited to large cerebral arteries and difficult to evaluate in the small perforating arteries due to insufficient spatial resolution. In this study, we assessed the feasibility to measure blood flow waveforms in the small lenticulostriate arteries with 7 Tesla velocity-sensitive MRI. The middle cerebral artery was included as reference. Imaging was performed in five young and five old healthy volunteers. Flow was calculated by integrating time-varying velocity values over the vascular cross-section. MRI acquisitions were performed twice in each subject to determine reproducibility. From the flow waveforms, the pulsatility index and damping factor were deduced. Reproducibility values, in terms of the intraclass correlation coefficients, were found to be good to excellent. Measured pulsatility index of the lenticulostriate arteries significantly increased and damping factor significantly decreased with age. In conclusion, we demonstrate that blood flow through the lenticostriate arteries can be precisely measured using 7 Tesla MRI and reveal effects of arterial stiffness due to aging. These findings hold promise to provide relevant insights into the pathologies involving perforating cerebral arteries.

  19. Experimental study on blood flow patterns through the phantoms of the intracranial arterial aneurysms using color Doppler imaging

    Chung, Tae Sub; Jeong, Eun Kee; Rhim, Yoon Chul; Kim, Sung Bin; Lee, Dong Hoon; Kim, Dae In

    1994-01-01

    The occurrence, growth, thrombosis, and rupture of intracranial saccular aneurysms can be directly related to the effect of hemodynamic forces. We developed the phantom flow models and compared with the computer simulation program to analyse the flow pattern and hemodynamics that might be responsible for the intracranial arterial aneurysms. We designed the arterial phantoms of three major sites of intracranial arterial aneurysm ; 1) basilar artery tip, 2) internal carotid artery bifurcation, 3) curved area of internal carotid artery. Flow patterns in the aneurysmal portion of phantoms were evaluated with color Doppler system on the connection with automatic closed type of circulation system. Then, we compared the results with computer simulation. The hemodynamic characteristics of the phantoms were identical with those obtained by computerisation's. Three distinct zones of flow were identified by color Doppler studies on the aneurysm of the curved area of an internal carotid artery : 1) an inflow zone entering the aneurysm at the distal aspect of its orifice, 2) an outflow zone exiting the aneurysm at the proximal aspect of its orifice, 3) a central slow vortex.However, the phantoms of basilar artery tip and artery bifurcation showed a direct inflow stream at the dome of an aneurysm. Flow dynamics in the various phantoms of the aneurysms can be successfully evaluated with color Doppler imaging, and were consistent with those predicted by computer simulations

  20. Radioembolization of hepatic tumors. Flow redistribution after the occlusion of intrahepatic arteries

    Lauenstein, T.C.; Heusner, T.A.; Antoch, G.; Hamami, M.; Bockisch, A.; Ertle, J.; Schlaak, J.F.; Gerken, G.

    2011-01-01

    Radioembolization using 90yttrium is an emerging therapy option for unresectable liver malignancies. In order to reduce the number of yttrium injections, endovascular occlusion of a segmental hepatic artery has been proposed. The aim of this study was to assess whether sufficient vascular redistribution of the occluded liver segments through intrahepatic collaterals can be observed. 27 patients with hepatocellular carcinoma (n = 16) or hepatic metastases (n = 11) were studied. Hepatic angiography was performed on average 16 days prior to radioembolization. The segment II/III artery (n = 9) or the segment IV artery (n = 18) was occluded using coils. Technectium-99m-labeled macroaggregated albumin (99mTc-MAA) was injected into the right and the remaining part of the left hepatic artery in order to identify any hepatic volume not included in the perfused area. Patients underwent a SPECT/CT on average 1 h after the 99mTc-MAA injection. Two radiologists evaluated the SPECT/CT scans regarding the presence of non-perfused hepatic segments. Furthermore, hepatic perfusion was assessed by digital subtraction angiography (DSA) on the day of radioembolization. In 16 / 27 patients (59 %) a perfusion of the occluded liver segment was visible on the SPECT/CT scan. In 8 / 11 patients without flow redistribution at the time of the SPECT/CT, perfusion of the occluded segment through hepatic collaterals was observed during angiography prior to radioembolization. Hence, flow redistribution was eventually found in 24 / 27 patients (89 %). Flow redistribution after the occlusion of intrahepatic arteries prior to radioembolization can be successfully induced in the majority of patients with anatomical variants of the hepatic arteries. (orig.)

  1. Luminal flow amplifies stent-based drug deposition in arterial bifurcations.

    Vijaya B Kolachalama

    2009-12-01

    Full Text Available Treatment of arterial bifurcation lesions using drug-eluting stents (DES is now common clinical practice and yet the mechanisms governing drug distribution in these complex morphologies are incompletely understood. It is still not evident how to efficiently determine the efficacy of local drug delivery and quantify zones of excessive drug that are harbingers of vascular toxicity and thrombosis, and areas of depletion that are associated with tissue overgrowth and luminal re-narrowing.We constructed two-phase computational models of stent-deployed arterial bifurcations simulating blood flow and drug transport to investigate the factors modulating drug distribution when the main-branch (MB was treated using a DES. Simulations predicted extensive flow-mediated drug delivery in bifurcated vascular beds where the drug distribution patterns are heterogeneous and sensitive to relative stent position and luminal flow. A single DES in the MB coupled with large retrograde luminal flow on the lateral wall of the side-branch (SB can provide drug deposition on the SB lumen-wall interface, except when the MB stent is downstream of the SB flow divider. In an even more dramatic fashion, the presence of the SB affects drug distribution in the stented MB. Here fluid mechanic effects play an even greater role than in the SB especially when the DES is across and downstream to the flow divider and in a manner dependent upon the Reynolds number.The flow effects on drug deposition and subsequent uptake from endovascular DES are amplified in bifurcation lesions. When only one branch is stented, a complex interplay occurs - drug deposition in the stented MB is altered by the flow divider imposed by the SB and in the SB by the presence of a DES in the MB. The use of DES in arterial bifurcations requires a complex calculus that balances vascular and stent geometry as well as luminal flow.

  2. MR velocity mapping measurement of renal artery blood flow in patients with impaired kidney function

    Cortsen, M; Petersen, L.J.; Stahlberg, F

    1996-01-01

    Renal blood flow (RBF) was measured in 9 patients with chronic impaired kidney function using MR velocity mapping and compared to PAH clearance and 99mTc-DTPA scintigraphy. An image plane suitable for flow measurement perpendicular to the renal arteries was chosen from 2-dimensional MR angiography....... MR velocity mapping was performed in both renal arteries using an ECG-triggered gradient echo pulse sequence previously validated in normal volunteers. Effective renal plasma flow was calculated from the clearance rate of PAH during constant infusion and the split of renal function was evaluated...... by 99mTc-DTPA scintigraphy. A reduction of RBF was found, and there was a significant correlation between PAH clearance multiplied by 1/(1-hematocrit) and RBF determined by MR velocity mapping. Furthermore, a significant correlation between the distribution of renal function and the percent distribution...

  3. Wall morphology, blood flow and wall shear stress: MR findings in patients with peripheral artery disease

    Galizia, Mauricio S.; Barker, Alex; Collins, Jeremy; Carr, James [Northwestern University, Department of Radiology, Feinberg School of Medicine, Chicago, IL (United States); Liao, Yihua [Northwestern University' s Feinberg School of Medicine, Department of Preventive Medicine, Chicago, IL (United States); McDermott, Mary M. [Northwestern University' s Feinberg School of Medicine, Department of Preventive Medicine, Chicago, IL (United States); Northwestern University' s Feinberg School of Medicine, Department of Medicine, Chicago, IL (United States); Markl, Michael [Northwestern University, Department of Radiology, Feinberg School of Medicine, Chicago, IL (United States); Northwestern University, Department Biomedical Engineering, McCormick School of Engineering, Chicago, IL (United States)

    2014-04-15

    To investigate the influence of atherosclerotic plaques on femoral haemodynamics assessed by two-dimensional (2D) phase-contrast (PC) magnetic resonance imaging (MRI) with three-directional velocity encoding. During 1 year, patients with peripheral artery disease and an ankle brachial index <1.00 were enrolled. After institutional review board approval and written informed consent, 44 patients (age, 70 ± 12 years) underwent common femoral artery MRI. Patients with contra-indications for MRI were excluded. Sequences included 2D time-of-flight, proton-density, T1-weighted and T2-weighted MRI. Electrocardiogram (ECG)-gated 2D PC-MRI with 3D velocity encoding was acquired. A radiologist classified images in five categories. Blood flow, velocity and wall shear stress (WSS) along the vessel circumference were quantified from the PC-MRI data. The acquired images were of good quality for interpretation. There were no image quality problems related to poor ECG-gating or slice positioning. Velocities, oscillatory shear stress and total flow were similar between patients with normal arteries and wall thickening/plaque. Patients with plaques demonstrated regionally increased peak systolic WSS and enhanced WSS eccentricity. Combined multi-contrast morphological imaging of the peripheral arterial wall with PC-MRI with three-directional velocity encoding is a feasible technique. Further study is needed to determine whether flow is an appropriate marker for altered endothelial cell function, vascular remodelling and plaque progression. (orig.)

  4. Effect of Acute Resistance Exercise on Carotid Artery Stiffness and Cerebral Blood Flow Pulsatility

    Wesley K Lefferts

    2014-03-01

    Full Text Available Arterial stiffness is associated with cerebral flow pulsatility. Arterial stiffness increases following acute resistance exercise (RE. Whether this acute RE-induced vascular stiffening affects cerebral pulsatility remains unknown. Purpose: To investigate the effects of acute RE on common carotid artery (CCA stiffness and cerebral blood flow velocity (CBFv pulsatility. Methods: Eighteen healthy men (22 ± 1 yr; 23.7 ± 0.5 kg∙m-2 underwent acute RE (5 sets, 5-RM bench press, 5 sets 10-RM bicep curls with 90 s rest intervals or a time control condition (seated rest in a randomized order. CCA stiffness (β-stiffness, Elastic Modulus (Ep and hemodynamics (pulsatility index, forward wave intensity and reflected wave intensity were assessed using a combination of Doppler ultrasound, wave intensity analysis and applanation tonometry at baseline and 3 times post-RE. CBFv pulsatility index was measured with transcranial Doppler at the middle cerebral artery (MCA. Results: CCA β-stiffness, Ep and CCA pulse pressure significantly increased post-RE and remained elevated throughout post-testing (p 0.05. There were significant increases in forward wave intensity post-RE (p0.05. Conclusion: Although acute RE increases CCA stiffness and pressure pulsatility, it may not affect CCA or MCA flow pulsatility. Increases in pressure pulsatility may be due to increased forward wave intensity and not pressure from wave reflections.

  5. Ultrasound analysis of mental artery flow in elderly patients: a case-control study.

    Baladi, Marina G; Tucunduva Neto, Raul R C M; Cortes, Arthur R G; Aoki, Eduardo M; Arita, Emiko S; Freitas, Claudio F

    2015-01-01

    Mental artery flow decreases with age and may have an aetiological role in alveolar ridge atrophy. The aim of this study was to identify factors associated with alterations of mental artery flow, assessed by ultrasonography. This case-control study was conducted on elderly patients (aged above 60 years) at the beginning of dental treatment. Intraoral B-mode Doppler ultrasonography was used to assess mental artery flow. The cases were defined as patients with a weak/absent ultrasound signal, whereas the controls presented a strong ultrasound signal. Demographics and radiographic findings (low bone mineral density on dual-energy X-ray absorptiometry and mandibular cortical index on panoramic radiographs) were analysed as risk factors for weak/absent ultrasound signal and were calculated as adjusted odds ratios (AORs) with 95% confidence intervals (CIs) using conditional logistic regression. In addition, the Student's t-test was used to compare the mean alveolar bone height of the analysed groups. A p-value <0.05 was considered statistically significant. A total of 30 ultrasound examinations (12 cases and 18 controls) were analysed. A weak/absent mental artery pulse strength was significantly associated with edentulism (AOR = 3.67; 95% CI = 0.86-15.63; p = 0.046). In addition, there was a significant difference in alveolar bone height between edentulous cases and controls (p = 0.036). Within the limitations of this study, the present results indicate that edentulism is associated with diminished mental artery flow, which, in turn, affects alveolar bone height.

  6. Ultrasound analysis of mental artery flow in elderly patients: a case–control study

    Baladi, Marina G; Tucunduva Neto, Raul R C M; Aoki, Eduardo M; Arita, Emiko S; Freitas, Claudio F

    2015-01-01

    Objectives: Mental artery flow decreases with age and may have an aetiological role in alveolar ridge atrophy. The aim of this study was to identify factors associated with alterations of mental artery flow, assessed by ultrasonography. Methods: This case–control study was conducted on elderly patients (aged above 60 years) at the beginning of dental treatment. Intraoral B-mode Doppler ultrasonography was used to assess mental artery flow. The cases were defined as patients with a weak/absent ultrasound signal, whereas the controls presented a strong ultrasound signal. Demographics and radiographic findings (low bone mineral density on dual-energy X-ray absorptiometry and mandibular cortical index on panoramic radiographs) were analysed as risk factors for weak/absent ultrasound signal and were calculated as adjusted odds ratios (AORs) with 95% confidence intervals (CIs) using conditional logistic regression. In addition, the Student's t-test was used to compare the mean alveolar bone height of the analysed groups. A p-value <0.05 was considered statistically significant. Results: A total of 30 ultrasound examinations (12 cases and 18 controls) were analysed. A weak/absent mental artery pulse strength was significantly associated with edentulism (AOR = 3.67; 95% CI = 0.86–15.63; p = 0.046). In addition, there was a significant difference in alveolar bone height between edentulous cases and controls (p = 0.036). Conclusions: Within the limitations of this study, the present results indicate that edentulism is associated with diminished mental artery flow, which, in turn, affects alveolar bone height. PMID:26205777

  7. [Influence of Sympathetic Denervation of the Renal Artery on the Level of Arterial Blood Pressure, Cerebral Blood Flow and Cognitive Function In Patients With Resistant Arterial Hypertension].

    Efimova, Y N; Lichikaki, A V; Lishmanov, B Y

    2017-07-01

    To study the effect of radiofrequency ablation of renal arteries on regional cerebral blood flow and cognitive function in patients with resistant arterial hypertension (AH). Transcatheter renal denervation (TRD) was performed in 17 patients with resistant AH. Examination before and after TRD included SPECT with mTc-HMPAO, 24-hours blood pressure (BP) monitoring, and comprehensive neuropsychological testing. Fifteen patients without angiographic signs of carotid atherosclerosis, coronary artery disease and AH, neurological and psychiatric disorders were investigated as control group. Compared with control group patients with AH had decreases of regional cerebral blood flow (rCBF) in right (by 13.5%, p=0.00002) and left (by 15.5%, p=0.0006) inferior frontal lobes, in right temporal brain region (by 11.5%, p=0.008); in right and left occipital lobes (by 8.2%, p=0.04). In 6 months after TRD we observed significant improvement of cognitive function, parameters of 24-hour BP monitoring, and rCBF. We also noted definite close interdependence between changes of rCBF, indices of 24-hours BP monitoring, and dynamics of cognitive function. Improvement of long-term verbal memory correlated with increases of rCBF in left superior frontal and right occipital regions while dynamics of mentation and attention correlated positively with augmentation of rCBF in right posterior parietal region. Changes of perfusion in inferior parts of left frontal lobe and in right occipital region correlated with dynamics of index of diurnal diastolic hypertension time (R2=0.64, p=0.001, and R2=0.60, p=0.03, respectively). Our results suggest, that in patients with resistant AH positive effect of TRD on levels of 24-hour mean BP as well as on indices of BP load leads to in augmentation of rCBF and improvement of cognitive function.

  8. Magnetization Transfer Effects on the Efficiency of Flow-driven Adiabatic Fast Passage Inversion of Arterial Blood

    Hernandez-Garcia, Luis; Lewis, David P.; Moffat, Bradford; Branch, Craig A.

    2007-01-01

    Continuous arterial spin labeling experiments typically use flow-driven adiabatic fast passage (AFP) inversion of the arterial blood water protons. In this article, we measure the effect of magnetization transfer in blood and how it affects the inversion label. We use modified Bloch equations to model flow-driven adiabatic inversion in the presence of magnetization transfer in blood flowing at velocities from 1 to 30 cm/s in order to explain our findings. Magnetization transfer results in a r...

  9. Ocular Sarcoidosis

    Pasadhika, Sirichai; Rosenbaum, James T

    2015-01-01

    Sarcoidosis is one of the leading causes of inflammatory eye disease. Ocular sarcoidosis can involve any part of the eye and its adnexal tissues, and may cause uveitis, episcleritis/scleritis, eyelid abnormalities, conjunctival granuloma, optic neuropathy, lacrimal gland enlargement and orbital inflammation. Glaucoma and cataract can be complications from inflammation itself or adverse effects from therapy. Ophthalmic manifestations can be isolated, or associated with other organ involvement. Patients with ocular sarcoidosis can present with a wide range of clinical presentations and severity. Multi-disciplinary approaches are required to achieve the best treatment outcomes for both ocular and systemic manifestations. PMID:26593141

  10. Successful flow reduction surgery for a ruptured true posterior communicating artery aneurysm caused by the common carotid artery ligation for epistaxis.

    Yamao, Yukihiro; Takahashi, Jun C; Satow, Tetsu; Iihara, Koji; Miyamoto, Susumu

    2014-01-01

    Carotid artery occlusion can lead to the development of rare true posterior communicating artery (PCoA) aneurysms because of hemodynamic stress on the PCoA. Surgical treatment of these lesions is challenging. The authors report a case of a true PCoA aneurysm that developed and ruptured 37 years after ligation of the ipsilateral common carotid artery for epistaxis. The lesion was successfully treated with clipping of the distal M1 segment of the middle cerebral artery (MCA) after the occipital artery-radial artery free graft-MCA bypass, which led to extreme reduction in collateral flow through the PCoA. A cortical branch, located just proximal to the obliteration site, functioned as a sufficient flow outlet. The aneurysm shrank, and the patient has been doing well without any symptoms for 5 years after surgery. M1 obliteration combined with high-flow extra-intracranial bypass might be a promising option for a true PCoA aneurysm, and therapeutic design that leaves a sufficient flow outlet on the M1 is mandatory to avoid unexpected occlusion of the M1 and its perforators.

  11. Computer aided approximation of flow rate through systemic-pulmonary arterial shunts (SPAS).

    Vennemann, Peter; Montag, Michael; Peters, Franz; Merzkirch, Wolfgang

    2012-02-22

    The discrimination of flow rates through bronchial arteries that are affected by pathological SPAS today still happens solely qualitatively. A reproducible quantification of flow rates, however, would enable the comprehension of phenomena like the intensified shunt perfusion seen in cases of chronic inflammations or the characterization of SPAS that may cause cardiovascular problems. A computational program is developed, that allows the modeling of individual bronchial arteries on the basis of the information provided by angiography. Angiographic images are available from the standard clinical assessment of SPAS. The flow through continuous and geometrically measurable vessel segments and SPAS is given by the law of Hagen-Poiseuille. The discharge through healthy branches is calculated by means of allometric scaling laws. The simulation results are verified by flow experiments in artificial vessel networks made of glass and PE tubing. The experimental set-up mimics realistic, pulsating pressure and flow conditions. When applied to the artificial vessel networks, the model described herein provides results for the volumetric flow rate that differ from values measured in laboratory experiments by volumetric flow through individual SPAS fairly independently from his experience and without the need of measurements additional to the mandatory angiography.

  12. The effects of fenoldopam on coronary conduit blood flow after coronary artery bypass graft surgery.

    Halpenny, M

    2012-02-03

    OBJECTIVE: To quantify the effects of fenoldopam, 0.1 microg\\/kg\\/min, on left internal mammary artery (LIMA) and saphenous vein blood flow after coronary anastomosis. DESIGN: Prospective, randomized, double-blind, placebo-controlled trial. SETTING: University teaching hospital, single institution. PARTICIPANTS: Thirty-one American Society of Anesthesiologists III patients undergoing elective coronary revascularization. INTERVENTIONS: A perivascular ultrasonic flow probe (Linton Instrumentation, Norfolk, UK) was placed around the LIMA and saphenous vein graft after coronary anastomosis. MEASUREMENTS AND MAIN RESULTS: Immediately before and at 5-minute intervals for 15 minutes after starting the infusion, blood flow was measured in the LIMA and one saphenous vein graft using a transit time ultrasonic flow probe. Heart rate, blood pressure, and central venous pressure were documented at these time points. Administration of fenoldopam, 0.1 microg\\/kg\\/min, did not alter heart rate or blood pressure. A small, nonsignificant increase in LIMA blood flow occurred during the 15-minute study period (30 +\\/- 12 to 35 +\\/- 10 mL\\/min) in patients who received fenoldopam. No significant changes occurred in the placebo group. CONCLUSIONS: The findings indicate that fenoldopam, 0.1 microg\\/kg\\/min, did not influence coronary conduit blood flow to a clinically significant extent. The small increase in LIMA blood flow may be of greater importance in high-risk patients or in the prevention of coronary arterial spasm.

  13. Demonstration of blood flow by color doppler in the femoral artery distal to arterial cannula during peripheral venoarterial-extracorporeal membrane oxygenation

    K G Suresh Rao

    2017-01-01

    Full Text Available In spite of distal perfusion of the limb using a cannula, the limb can have ischemic events if there is an undetected kink or clot anywhere in the line or thrombus in the artery. There are several ways to monitor and assess the limb ischemia. Monitoring for clinical signs of limb ischemia like temperature change and pallor is reliable and mandatory. We report a method where we used color Doppler to document the blood flow. Curvilinear vascular probe of an echo machine is used to identify the flow in the distal femoral artery of the lower limb. . As we have demonstrated in the video attached, once flow to the distal limb perfusion system is shut off by closing the three way stop cock, we can appreciate the immediate cessation of flow in the artery by Doppler.

  14. MRI-based flow measurements in the main pulmonary artery to detect pulmonary arterial hypertension in patients with cystic fibrosis

    Wolf, T.; Anjorin, A.; Abolmaali, N.; Posselt, H.; Smaczny, C.; Vogl, T.J.

    2009-01-01

    Development of pulmonary arterial hypertension (PH) is a common problem in the course of patients suffering from cystic fibrosis (CF). This study was performed to evaluate MRI based flow measurements (MR venc ; Velocity ENCoding) to detect signs of an evolving PH in patients suffering from CF. 48 patients (median age: 16 years, range: 10 - 40 years, 25 female) suffering from CF of different severity (mean FEV1: 74 % ± 23, mean Shwachman-score: 63 ± 10) were examined using MRI based flow measurements of the main pulmonary artery (MPA). Phase-contrast flash sequences (TR: 9.6 ms, TE: 2.5 ms, bandwidth: 1395 Hertz/Pixel) were utilized. Results were compared to an age- and sex-matched group of 48 healthy subjects. Analyzed flow data where: heart frequency (HF), cardiac output (HZV), acceleration time (AT), proportional acceleration time related to heart rate (ATr), mean systolic blood velocity (MFG), peak velocity (Peak), maximum flow (Fluss max ), mean flow (Fluss mitt ) and distensibility (Dist). The comparison of means revealed significant differences only for MFG, Fluss max and Dist, but overlap was marked. However, using a scatter-plot of AT versus MFG, it was possible to identify five CF-patients demonstrating definite signs of PH: AT = 81 ms ± 14, MFG = 46 ± 11 cm/s, Dist = 41 % ± 7. These CF-patients where the most severely affected in the investigated group, two of them were listed for complete heart and lung transplantation. The comparison of this subgroup and the remaining CF-patients revealed a highly significant difference for the AT (p = 0.000001) without overlap. Screening of CF-patients for the development of PH using MR venc of the MPA is not possible. In later stages of disease, the quantification of AT, MFG and Dist in the MPA may be useful for the detection, follow-up and control of therapy of PH. MR venc of the MPA completes the MRI-based follow-up of lung parenchyma damage in patients suffering from CF. (orig.)

  15. Traumatismos oculares Ocular traumas

    Gelen Welch Ruiz

    2007-12-01

    Full Text Available Se realizó un estudio descriptivo de tipo retrospectivo longitudinal cuyo universo estuvo constituido por 72 ojos de 72 pacientes con traumatismos oculares mecánicos que fueron hospitalizados en el Hospital Militar Central “Dr. Carlos J. Finlay” desde enero de 1999 hasta enero de 2005. Para el análisis estadístico de la información se utilizó el programa automatizado SPSS versión 11.5 en el cual también se conformó la base de datos y se realizaron los cálculos de acuerdo con el tipo de variable analizada. Se utilizaron medidas de resumen, tendencia central y asociación estadística con un nivel de significación de p A retrospective longitudinal and descriptive study was carried out in 72 eyes from 72 patients with mechanical occular traumas, who had been hospitalized in “Dr. Carlos J. Finlay” Military Hospital from December 1999 to January 2005. For the statistical data analysis, an automated program (SPSS 11.5 version was used to create the database and estimations were made according to the variable types. Summary measures, central tendency measures and statistical association with significance level equal to p < 0.05 were employed. Males prevailed (95.8%, the average age was 30.26 years with a minimum rate of 17 years and maximum rate of 82 years. The most frequent mechanisms of trauma were aggressions (23. 6% and injures from secondary projectiles (13.9%. The anterior segment traumas were more frequent (61, 1% than posterior segment traumas (6.94%. Both segments of the eyeball were affected in 39, 1% of eyes which evinced the worst visual acuity. The most common associated injures were hyphema (54, 2% and vitreous hemorrhage (16.6%. Closed trauma (contusions were more common and most of the eyes had better final visual acuity (45, 2% with vision range of 0.6-1.0 and 26.2% with vision range of 0.59-0.1. On the other hand, eyes affected by open trauma (simple wound, contusion-wound, wound with intraocular foreign body and

  16. Accurate evaluation of viscoelasticity of radial artery wall during flow-mediated dilation in ultrasound measurement

    Sakai, Yasumasa; Taki, Hirofumi; Kanai, Hiroshi

    2016-07-01

    In our previous study, the viscoelasticity of the radial artery wall was estimated to diagnose endothelial dysfunction using a high-frequency (22 MHz) ultrasound device. In the present study, we employed a commercial ultrasound device (7.5 MHz) and estimated the viscoelasticity using arterial pressure and diameter, both of which were measured at the same position. In a phantom experiment, the proposed method successfully estimated the elasticity and viscosity of the phantom with errors of 1.8 and 30.3%, respectively. In an in vivo measurement, the transient change in the viscoelasticity was measured for three healthy subjects during flow-mediated dilation (FMD). The proposed method revealed the softening of the arterial wall originating from the FMD reaction within 100 s after avascularization. These results indicate the high performance of the proposed method in evaluating vascular endothelial function just after avascularization, where the function is difficult to be estimated by a conventional FMD measurement.

  17. Relationship between haemodynamic impairment and collateral blood flow in carotid artery disease.

    Hartkamp, Nolan S; Petersen, Esben T; Chappell, Michael A; Okell, Thomas W; Uyttenboogaart, Maarten; Zeebregts, Clark J; Bokkers, Reinoud Ph

    2017-01-01

    Collateral blood flow plays a pivotal role in steno-occlusive internal carotid artery (ICA) disease to prevent irreversible ischaemic damage. Our aim was to investigate the effect of carotid artery disease upon cerebral perfusion and cerebrovascular reactivity and whether haemodynamic impairment is influenced at brain tissue level by the existence of primary and/or secondary collateral. Eighty-eight patients with steno-occlusive ICA disease and 29 healthy controls underwent MR examination. The presence of collaterals was determined with time-of-flight, two-dimensional phase contrast MRA and territorial arterial spin labeling (ASL) imaging. Cerebral blood flow and cerebrovascular reactivity were assessed with ASL before and after acetazolamide. Cerebral haemodynamics were normal in asymptomatic ICA stenosis patients, as opposed to patients with ICA occlusion, in whom the haemodynamics in both hemispheres were compromised. Haemodynamic impairment in the affected brain region was always present in symptomatic patients. The degree of collateral blood flow was inversely correlated with haemodynamic impairment. Recruitment of secondary collaterals only occurred in symptomatic ICA occlusion patients. In conclusion, both CBF and cerebrovascular reactivity were found to be reduced in symptomatic patients with steno-occlusive ICA disease. The presence of collateral flow is associated with further haemodynamic impairment. Recruitment of secondary collaterals is associated with severe haemodynamic impairment.

  18. An Outflow Boundary Condition Model for Noninvasive Prediction of Fractional Flow Reserve in Diseased Coronary Arteries.

    Fayssal, Iyad A; Moukalled, Fadl; Alam, Samir; Isma'eel, Hussain

    2018-04-01

    This paper reports on a new boundary condition formulation to model the total coronary myocardial flow and resistance characteristics of the myocardial vascular bed for any specific patient when considered for noninvasive diagnosis of ischemia. The developed boundary condition model gives an implicit representation of the downstream truncated coronary bed. Further, it is based on incorporating patient-specific physiological parameters that can be noninvasively extracted to account for blood flow demand to the myocardium at rest and hyperemic conditions. The model is coupled to a steady three-dimensional (3D) collocated pressure-based finite volume flow solver and used to characterize the "functional significance" of a patient diseased coronary artery segment without the need for predicting the hemodynamics of the entire arterial system. Predictions generated with this boundary condition provide a deep understanding of the inherent challenges behind noninvasive image-based diagnostic techniques when applied to human diseased coronary arteries. The overall numerical method and formulated boundary condition model are validated via two computational-based procedures and benchmarked with available measured data. The newly developed boundary condition is used via a designed computational methodology to (a) confirm the need for incorporating patient-specific physiological parameters when modeling the downstream coronary resistance, (b) explain the discrepancies presented in the literature between measured and computed fractional flow reserve (FFRCT), and (c) discuss the current limitations and future challenges in shifting to noninvasive assessment of ischemia.

  19. Experimental investigations of the steady flow through an idealized model of a femoral artery bypass

    Giurgea Corina

    2014-03-01

    Full Text Available The present paper presents the steps taken by the authors in the first stage of an experimental program within a larger national research project whose objective is to characterize the flow through a femoral artery bypass with a view to finding solutions for its optimization. The objective of the stage is to investigate by means of the PIV method the stationary flow through a bypass model with an idealized geometry. A bypass assembly which reunites the idealized geometry models of the proximal and distal anastomoses, and which respects the lengths of a femoral artery bypass was constructed on the basis of data for a real patient provided by medical investigations. With the aim of testing the model and the established experimental set-up with regard to their suitability for the assessment of the velocity field associated to the steady flow through the bypass, three zones that can restore the whole distal anastomosis were PIV investigated. The measurements were taken in the conditions of maintained inflow at the bypass entry of 0.9 l / min (Re = 600. The article presents comparatively the flow spectra and the velocity fields for each zone obtained in two situations: with the femoral artery completely occluded and completely open.

  20. The relationship of flow velocities to vessel diameters differs between extracranial carotid and vertebral arteries of stroke patients.

    Owolabi, Mayowa O; Agunloye, Atinuke M; Ogunniyi, Adesola

    2014-01-01

    Chronic changes in flow rate through arteries produce adjustment of arterial diameters. We compared the relationship between flow velocity and diameter in the carotid and in the vertebral arteries of stroke patients. Using triplex ultrasonography, the internal diameter and flow velocities of the common carotid, internal carotid, and vertebral arteries of 176 consecutive stroke patients were measured. Correlations were examined with Pearson's statistics at an alpha level of 0.05. Mean age of the patients was 59.3 ± 12 years, and 66% had cerebral infarcts. Diameter and blood flow velocities showed significant negative correlations (-0.115 ≥ r ≥ -0.382) in the carotid arteries on both sides, but positive correlations (0.211 ≤ r ≤ 0.320) in the vertebral arteries, even after controlling for age, gender, and blood pressure. Our study demonstrated different diameter/flow relationships in the carotid and the vertebral arteries of stroke patients, which may suggest pathologic changes in the adaptive processes governing vessel diameter and growth, especially in the carotid arteries. Copyright © 2013 Wiley Periodicals, Inc.

  1. Status of systemic to pulmonary arterial collateral flow after the fontan procedure.

    Whitehead, Kevin K; Harris, Matthew A; Glatz, Andrew C; Gillespie, Matthew J; DiMaria, Michael V; Harrison, Neil E; Dori, Yoav; Keller, Marc S; Rome, Jonathan J; Fogel, Mark A

    2015-06-15

    The investigators recently validated a method of quantifying systemic-to-pulmonary arterial collateral flow using phase-contrast magnetic resonance imaging velocity mapping. Cross-sectional data suggest decreased collateral flow in patients with total cavopulmonary connections (TCPCs) compared with those with superior cavopulmonary connections (SCPCs). However, no studies have examined serial changes in collateral flow from SCPCs to TCPCs in the same patients. The aim of this study was to examine differences in collateral flow between patients with SCPCs and those with TCPCs. Collateral flow was quantified by 2 independent measures from 250 single-ventricle studies in 219 different patients (115 SCPC and 135 TCPC studies, 31 patients with both) and 18 controls, during routine studies using through-plane phase-contrast magnetic resonance imaging. Collateral flow was indexed to body surface area, aortic flow, and pulmonary venous flow. Regardless of indexing method, SCPC patients had significantly higher collateral flow than TCPC patients (1.64 ± 0.8 vs 1.03 ± 0.8 L/min/m(2), p <0.001). In 31 patients who underwent serial examinations, collateral flow as a fraction of aortic flow increased early after TCPC completion. In TCPC patients, indexed collateral flow demonstrated a significant negative correlation with time from TCPC. In conclusion, SCPC and TCPC patients demonstrate substantial collateral flow, with SCPC patients having higher collateral flow than TCPC patients overall. On the basis of the paired subset analysis, collateral flow does not decrease in the short term after TCPC completion and trends toward an increase. In the long term, however, collateral flow decreases over time after TCPC completion. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. A Study Demonstrating the Quantitative Relationship Between Internal Thoracic Artery Length and Free Flow.

    Gode, Safa; Sen, Onur; Kadirogulları, Ersin; Reyhancan, Adem; Kyaruzi, Mugisha; Satılmısoglu, Muhammet Hulusi; Erkanlı, Korhan

    2017-08-09

    The left internal thoracic artery (LITA) is the most commonly used arterial bypass conduit in coronary artery bypass graft (CABG) patients and inadequate LITA flow can result in an increase in morbidity and mortality. In this study, we evaluated the effect of excision of the distal spasmodic segment of the LITA on the free flow in CABG patients. This study consisted of 47 patients who underwent elective CABG performed with or without other cardiac surgery, between July 2015 and December 2015. Excised LITA length was shorter than 15mm in group 1, between 15mm and 30mm in group 2 and longer than 30mm in group 3. Left ITA free flow was measured for 60seconds into a container before and after the distal LITA excision. The inter-measurement differences were calculated for the three groups. Thereafter, the comparison was performed in terms of free flow difference amongst the three groups. The mean difference of LITA free flow was 27.6±22.7ml/minute in group 1, 35.4±26.7ml/minute in group 2, and 52.6±26.1ml/minute in group 3. There were significant differences in terms of free flow difference between the groups (p=0.008). Also, differences were statistically significant in group 1 versus group 3 (p=0.003) and group 2 versus group 3 (p=0.038) in the intergroup comparisons. The distal part of the LITA has more spasmodic potential than other segments. This spasm may result in low flow of LITA grafts. Therefore, an as long as possible excision of the distal LITA segment may be required to avoid the spasmodic effect. Copyright © 2017 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier B.V. All rights reserved.

  3. Patient Specific Multiscale Simulations of Blood Flow in Coronary Artery Bypass Surgery

    Bangalore Ramachandra, Abhay; Sankaran, Sethuraman; Kahn, Andrew M.; Marsden, Alison L.

    2013-11-01

    Coronary artery bypass surgery is performed to revascularize blocked coronary arteries in roughly 400,000 patients per year in the US.While arterial grafts offer superior patency, vein grafts are used in more than 70% of procedures, as most patients require multiple grafts. Vein graft failure (approx. 50% within 10 years) remains a major clinical issue. Mounting evidence suggests that hemodynamics plays a key role as a mechano-biological stimulus contributing to graft failure. However, quantifying relevant hemodynamic quantities (e.g. wall shear stress) invivo is not possible directly using clinical imaging techniques. We numerically compute graft hemodynamics in a cohort of 3-D patient specific models using a stabilized finite element method. The 3D flow domain is coupled to a 0D lumped parameter circulatory model. Boundary conditions are tuned to match patient specific blood pressures, stroke volumes & heart rates. Results reproduce clinically observed coronary flow waveforms. We quantify differences in multiple hemodynamic quantities between arterial & venous grafts & discuss possible correlations between graft hemodynamics & clinically observed graft failure.Such correlations will provide further insight into mechanisms of graft failure and may lead to improved clinical outcomes.

  4. Diastolic coronary artery pressure-flow velocity relationships in conscious man.

    Dole, W P; Richards, K L; Hartley, C J; Alexander, G M; Campbell, A B; Bishop, V S

    1984-09-01

    We characterised the diastolic pressure-flow velocity relationship in the normal left coronary artery of conscious man before and after vasodilatation with angiographic contrast medium. Phasic coronary artery pressure and flow velocity were measured in ten patients during individual diastoles (0.5 to 1.0 s) using a 20 MHz catheter-tipped, pulsed Doppler transducer. All pressure-flow velocity curves were linear over the diastolic pressure range of 110 +/- 15 (SD) mmHg to 71 +/- 7 mmHg (r = 0.97 +/- 0.01). In the basal state, values for slope and extrapolated zero flow pressure intercept averaged 0.35 +/- 0.12 cm X s-1 X mmHg-1 and 51.7 +/- 8.6 mmHg, respectively. Vasodilatation resulted in a 2.5 +/- 0.5 fold increase in mean flow velocity. The diastolic pressure-flow velocity relationship obtained during peak vasodilatation compared to that during basal conditions was characterised by a steeper slope (0.80 +/- 0.48 cm X s-1 X mmHg-1, p less than 0.001) and lower extrapolated zero flow pressure intercept (37.9 +/- 9.8 mmHg, p less than 0.05). Mean right atrial pressure for the group averaged 4.4 +/- 1.7 mmHg, while left ventricular end-diastolic pressure averaged 8.7 +/- 2.8 mmHg. These observations in man are similar to data reported in the canine coronary circulation which are consistent with a vascular waterfall model of diastolic flow regulation. In this model, coronary blood flow may be regulated by changes in diastolic zero flow pressure as well as in coronary resistance.

  5. Cerebral blood flow response to changes in arterial carbon dioxide tension during hypothermic cardiopulmonary bypass in children

    Kern, F.H.; Ungerleider, R.M.; Quill, T.J.; Baldwin, B.; White, W.D.; Reves, J.G.; Greeley, W.J.

    1991-01-01

    We examined the relationship of changes in partial pressure of carbon dioxide on cerebral blood flow responsiveness in 20 pediatric patients undergoing hypothermic cardiopulmonary bypass. Cerebral blood flow was measured during steady-state hypothermic cardiopulmonary bypass with the use of xenon 133 clearance methodology at two different arterial carbon dioxide tensions. During these measurements there was no significant change in mean arterial pressure, nasopharyngeal temperature, pump flow rate, or hematocrit value. Cerebral blood flow was found to be significantly greater at higher arterial carbon dioxide tensions (p less than 0.01), so that for every millimeter of mercury rise in arterial carbon dioxide tension there was a 1.2 ml.100 gm-1.min-1 increase in cerebral blood flow. Two factors, deep hypothermia (18 degrees to 22 degrees C) and reduced age (less than 1 year), diminished the effect carbon dioxide had on cerebral blood flow responsiveness but did not eliminate it. We conclude that cerebral blood flow remains responsive to changes in arterial carbon dioxide tension during hypothermic cardiopulmonary bypass in infants and children; that is, increasing arterial carbon dioxide tension will independently increase cerebral blood flow

  6. Comparison of fractional flow reserve of composite Y-grafts with saphenous vein or right internal thoracic arteries.

    Glineur, David; Boodhwani, Munir; Poncelet, Alain; De Kerchove, Laurent; Etienne, Pierre Yves; Noirhomme, Philippe; Deceuninck, Paul; Michel, Xavier; El Khoury, Gebrine; Hanet, Claude

    2010-09-01

    Composite Y-grafts, using the left internal thoracic artery as the inflow, allow a more efficient use of conduits without the need to touch a diseased ascending aorta. Among other conduits, the saphenous vein graft may be an alternative to the radial artery in elderly patients. We evaluated the hemodynamic characteristics of 17 composite Y-grafts made with the left internal thoracic artery anastomosed to the left anterior descending coronary artery in all cases and with either the free right internal thoracic artery (RITA group, n = 10) or a saphenous vein graft (SVG group, n = 7) implanted proximally to the left internal thoracic artery and distally to the circumflex territory 6 months after the operation. At baseline, the pressure gradient measured with a 0.014-inch pressure wire was minimal between the aorta and the internal thoracic artery stem (2 +/- 1 mm Hg), the internal thoracic artery and left anterior descending (4 +/- 2 mm Hg), the internal thoracic artery and left circumflex (3 +/- 1 mm Hg), and the saphenous vein graft and left circumflex (2 +/- 2 mm Hg). During hyperemia induced by adenosine, the pressure gradient increased significantly to 6 +/- 2 mm Hg in the internal thoracic artery stem, 9 +/- 4 mm Hg in the internal thoracic artery and left anterior descending artery, 9 +/- 3 mm Hg in the internal thoracic artery and left circumflex, and 7 +/- 4 mm Hg in the saphenous vein graft and left circumflex. Fractional flow reserve was 0.94 +/- 0.02 in internal thoracic artery stem, 0.90 +/- 0.04 mm Hg in the internal thoracic artery and left anterior descending, 0.91 +/- 0.03 mm Hg in the internal thoracic artery and left circumflex, and 0.92 +/- 0.06 mm Hg in the saphenous vein graft and left circumflex. No difference between the two types of composite Y-grafts was observed for pressure gradients or fractional flow reserve measured in internal thoracic artery stem or in distal branches. Composite Y-grafts with saphenous vein or right internal thoracic

  7. Relationship between haemodynamic impairment and collateral blood flow in carotid artery disease

    Hartkamp, Nolan S; Petersen, Esben T; Chappell, Michael A

    2018-01-01

    Collateral blood flow plays a pivotal role in steno-occlusive internal carotid artery (ICA) disease to prevent irreversible ischaemic damage. Our aim was to investigate the effect of carotid artery disease upon cerebral perfusion and cerebrovascular reactivity and whether haemodynamic impairment...... is influenced at brain tissue level by the existence of primary and/or secondary collateral. Eighty-eight patients with steno-occlusive ICA disease and 29 healthy controls underwent MR examination. The presence of collaterals was determined with time-of-flight, two-dimensional phase contrast MRA and territorial....... In conclusion, both CBF and cerebrovascular reactivity were found to be reduced in symptomatic patients with steno-occlusive ICA disease. The presence of collateral flow is associated with further haemodynamic impairment. Recruitment of secondary collaterals is associated with severe haemodynamic impairment....

  8. Evaluation of Coronary Artery Stenosis by Quantitative Flow Ratio During Invasive Coronary Angiography

    Westra, Jelmer; Tu, Shengxian; Winther, Simon

    2018-01-01

    BACKGROUND: Quantitative flow ratio (QFR) is a novel diagnostic modality for functional testing of coronary artery stenosis without the use of pressure wires and induction of hyperemia. QFR is based on computation of standard invasive coronary angiographic imaging. The purpose of WIFI II (Wire...... patients with suspected coronary artery disease on coronary computed tomographic angiography for diagnostic invasive coronary angiography. Fractional flow reserve (FFR) was measured in all segments with 30% to 90% diameter stenosis. Blinded observers calculated QFR (Medis Medical Imaging bv......, The Netherlands) for comparison with FFR. FFR was measured in 292 lesions from 191 patients. Ten (5%) and 9 patients (5%) were excluded because of FFR and angiographic core laboratory criteria, respectively. QFR was successfully computed in 240 out of 255 lesions (94%) with a mean diameter stenosis of 50...

  9. Middle cerebral artery blood velocity and cerebral blood flow and O2 uptake during dynamic exercise

    Madsen, P L; Sperling, B K; Warming, T

    1993-01-01

    Results obtained by the 133Xe clearance method with external detectors and by transcranial Doppler sonography (TCD) suggest that dynamic exercise causes an increase of global average cerebral blood flow (CBF). These data are contradicted by earlier data obtained during less-well-defined conditions....... To investigate this controversy, we applied the Kety-Schmidt technique to measure the global average levels of CBF and cerebral metabolic rate of oxygen (CMRO2) during rest and dynamic exercise. Simultaneously with the determination of CBF and CMRO2, we used TCD to determine mean maximal flow velocity...... in the middle cerebral artery (MCA Vmean). For values of CBF and MCA Vmean a correction for an observed small drop in arterial PCO2 was carried out. Baseline values for global CBF and CMRO2 were 50.7 and 3.63 ml.100 g-1.min-1, respectively. The same values were found during dynamic exercise, whereas a 22% (P

  10. WE-FG-206-05: New Arterial Spin Labeling Method for Simultaneous Estimation of Arterial Cerebral Blood Volume, Cerebral Blood Flow and Arterial Transit Time

    Johnston, M; Whitlow, C; Jung, Y [Wake Forest School of Medicine, Winston-Salem, NC (United States); Liu, H [UT MD Anderson Cancer Center, Houston, TX (United States)

    2016-06-15

    Purpose: To demonstrate the feasibility of a novel Arterial Spin Labeling (ASL) method for simultaneously measuring cerebral blood flow (CBF), arterial transit time (ATT), and arterial cerebral blood volume (aCBV) without the use of a contrast agent. Methods: A series of multi-TI ASL images were acquired from one healthy subject on a 3T Siemens Skyra, with the following parameters: PCASL labeling with variable TI [300, 400, 500, 600, 700, 800, 900, 1000, 1500, 2000, 2500, 3000, 3500, 4000] ms, labeling bolus 1400 ms when TI allows, otherwise 100 ms less than TI, TR was minimized for each TI, two sinc shaped pre-saturation pulses were applied in the imaging plane immediately before 2D EPI acquisition. 64×64×24 voxels, 5 mm slice thickness, 1 mm gap, full brain coverage, 6 averages per TI, no crusher gradients, 11 ms TE, scan time of 4:56. The perfusion weighted time-series was created for each voxel and fit to a novel model. The model has two components: 1) the traditional model developed by Buxton et al., accounting for CBF and ATT, and 2) a box car function characterizing the width of the labeling bolus, with variable timing and height in proportion to the aCBV. All three parameters were fit using a nonlinear fitting routine that constrained all parameters to be positive. The main purpose of the high-temporal resolution TI sampling for the first second of data acquisition was to precisely estimate the blood volume component for better detection of arrival time and magnitude of signal. Results: Whole brain maps of CBF, ATT, and aCBV were produced, and all three parameters maps are consistent with similar maps described in the literature. Conclusion: Simultaneous mapping of CBF, ATT, and aCBV is feasible with a clinically tractable scan time (under 5 minutes).

  11. Echocardiographic and hemodynamic determinants of right coronary artery flow reserve and phasic flow pattern in advanced non-ischemic cardiomyopathy

    Mady Charles

    2007-09-01

    Full Text Available Abstract Background In patients with advanced non-ischemic cardiomyopathy (NIC, right-sided cardiac disturbances has prognostic implications. Right coronary artery (RCA flow pattern and flow reserve (CFR are not well known in this setting. The purpose of this study was to assess, in human advanced NIC, the RCA phasic flow pattern and CFR, also under right-sided cardiac disturbances, and compare with left coronary circulation. As well as to investigate any correlation between the cardiac structural, mechanical and hemodynamic parameters with RCA phasic flow pattern or CFR. Methods Twenty four patients with dilated severe NIC were evaluated non-invasively, even by echocardiography, and also by cardiac catheterization, inclusive with Swan-Ganz catheter. Intracoronary Doppler (Flowire data was obtained in RCA and left anterior descendent coronary artery (LAD before and after adenosine. Resting RCA phasic pattern (diastolic/systolic was compared between subgroups with and without pulmonary hypertension, and with and without right ventricular (RV dysfunction; and also with LAD. RCA-CFR was compared with LAD, as well as in those subgroups. Pearson's correlation analysis was accomplished among echocardiographic (including LV fractional shortening, mass index, end systolic wall stress more hemodynamic parameters with RCA phasic flow pattern or RCA-CFR. Results LV fractional shortening and end diastolic diameter were 15.3 ± 3.5 % and 69.4 ± 12.2 mm. Resting RCA phasic pattern had no difference comparing subgroups with vs. without pulmonary hypertension (1.45 vs. 1.29, p = NS either with vs. without RV dysfunction (1.47 vs. 1.23, p = NS; RCA vs. LAD was 1.35 vs. 2.85 (p Conclusion In patients with chronic advanced NIC, RCA phasic flow pattern has a mild diastolic predominance, less marked than in LAD, with no effects from pulmonary artery hypertension or RV dysfunction. There is no significant correlation between any cardiac mechanical-structural or

  12. Impact of top end anastomosis design on patency and flow stability in coronary artery bypass grafting.

    Koyama, Sachi; Kitamura, Tadashi; Itatani, Keiichi; Yamamoto, Tadashi; Miyazaki, Shohei; Oka, Norihiko; Nakashima, Kouki; Horai, Tetsuya; Ono, Minoru; Miyaji, Kagami

    2016-05-01

    For coronary artery bypass grafting (CABG), free grafts such as a saphenous vein or radial artery are often used for grafts to the lateral and posterior walls. However, the relationship between top-end anastomosis design and long-term patency remains unknown. Because coronary artery blood flow is dominant during diastole, top-end anastomosis may work better if the graft is directed towards the apex, whereas the shortest graft pathway appears to be most efficient. Using computational fluid dynamic models, we evaluated the hemodynamic variables that were affected by the angle of the top-end anastomosis. We created three-dimensional geometries of the aortic root with coronary arteries that involved 75 % stenosis in the obtuse marginal and postero-lateral branches. Two bypass models under vasodilator administration were created: in a"Model A", the top-end anastomosis is parallel to the long axis of the ascending aorta and the graft passed over the conus directed towards the apex; in a "Model B", the top-end anastomosis is directed toward the shortest pathway, and form near the right angles to the long axis of the ascending aorta. Wall shear stress (WSS) and its fluctuation, an oscillatory shear index (OSI) were evaluated to predict fibrosis progression at the anastomosis site and graft flow. Graft flow was 197.3 ml/min and 207.3 ml/min in the "Model A" and "Model B", respectively. The minimal WSS value inside the graft with the "Model A" and "Model B" was 0.53 Pa and 4.09 Pa, respectively, and the OSI value was 0.46 and 0.04, respectively. The top-end anastomosis of a free graft should be directed vertically towards the aorta to achieve the shortest graft pathway to maintain a high graft flow rate and to avoid the risks of endothelial fibrosis and plaque progression over the long-term after CABG.

  13. Fourier Analysis of Peripheral Blood Pressure and Flow in Intraoperative Assessment of Infrainguinal Arterial Reconstructions

    Cheshmedzhiev Mihail V.

    2014-08-01

    Full Text Available AIM: To assess infrainguinal arterial reconstructions by intraoperative flowmetry under the distal anastomosis using a fast Fourier transformation; calculate and compare the amplitude ratios of peripheral arterial blood pressure and volume flow before and after drug-induced vasodilation of occluded bypass grafts and bypass grafts that have been patent at least for 1 year. To find what magnitude of the change of these ratios indicate a long-term patency of the bypass grafting. PATIENTS AND METHODS: We compared the results of the intraoperative flowmetry tests of 97 patients with infrainguinal arterial reconstructions. The patients were divided into two groups based on the graft status: the grafts in 49 patients were patent for at least a year, and 48 patients had failed bypass. We used a fast Fourier transform (FFT of the pressure and blood flow waves and compared the ratios of their amplitudes before and after administration of a vasodilator drug into the graft. Comparing the ratios obtained before and those after administration of the drug we quantified their change in each group and analysed them. RESULTS: After a drug-induced vasodilation, the blood pressure and flow amplitude ratios for the group with compromised reconstructions were less than 1.9 times smaller than those before drug infusion, while for the group with bypass grafts that had been functional for at least 12 months the ratios declined by more than 1.9≈2 times. CONCLUSION: The magnitude of the change of amplitude ratios of the peripheral pressure and volume flow after drug-induced vasodilation can be used to make an assessment of the bypass graft and the distal arterial segment.

  14. Spontaneous regression of two supraophthalmic internal cerebral artery aneurysms following flow pattern alteration

    Hans, F.J.; Reinges, M.H.T.; Krings, T.; Mull, M.

    2004-01-01

    We report on a patient with fibromuscular dysplasia who presented with a right-sided giant calcified cavernous internal carotid artery (ICA) aneurysm and two additional supraophthalmic ICA aneurysms. Endovascular closure of the right ICA using detachable balloons was performed with collateralisation of the right hemisphere via the right-sided posterior communicating and the anterior communicating arteries. Repeat angiography after 6 months demonstrated spontaneous complete regression of the two supraophthalmic aneurysms, although the parent vessel was still perfused. In comparison to the former angiography, the flow within the parent vessel was reversed due to the proximal ICA balloon occlusion. MRI demonstrated that the aneurysms were not obliterated by thrombosis alone, but showed a real regression in size. This case report demonstrates that changes in cerebral hemodynamics potentially lead to plastic changes in the vessel architecture in adults and that aneurysms can be flow-related, even if not associated with high flow fistulas or arteriovenous malformations, especially in cases with an arterial wall disease. (orig.)

  15. Novel flow quantification of the carotid bulb and the common carotid artery with vector flow ultrasound

    Pedersen, Mads Møller; Pihl, Michael Johannes; Haugaard, Per

    2014-01-01

    technique transverse oscillation the blood velocities of both the axial and the transverse directions are obtained and the complexity of blood flow can be visualized. The aim of the study was to determine the technical performance and interpretation of vector concentration as a tool for estimation of flow...... (US) using a commercial vector flow ultrasound scanner (ProFocus, BK Medical, Denmark) with a linear 5 MHz transducer transverse oscillation vector flow software. CCA and CB areas were marked in one cardiac cycle from each volunteer. The complex flow was assessed by medical expert evaluation...... and by vector concentration calculation. A vortex with complex flow was found in all carotid bulbs, whereas the CCA had mainly laminar flow. The medical experts evaluated the flow to be mainly laminar in the CCA (0.82 +/- 0.14) and mainly complex (0.23 +/- 0.22) in the CB. Likewise, the estimated vector...

  16. Hemoglobin, hematocrit, and changes in cerebral blood flow : The Second Manifestations of ARTerial disease-Magnetic Resonance study

    van der Veen, Pieternella H.; Muller, Majon; Vincken, Koen L.; Westerink, Jan; Mali, Willem P. T. M.; van der Graaf, Yolanda; Geerlings, Mirjam I.; Doevendans, PAFM

    Hemoglobin and hematocrit are important determinants of blood viscosity and arterial oxygen content and may therefore influence cerebral blood flow (CBF). We examined cross-sectional and prospective associations of hemoglobin and hematocrit with CBF in 569 patients with manifest arterial disease

  17. Numerical simulation of heat transfer in power law fluid flow through a stenosed artery

    Talib, Amira Husni; Abdullah, Ilyani

    2017-11-01

    A numerical study of heat transfer in a power law fluid is investigated in this paper. The blood flow is treated as power law fluid with a presence of cosine shaped stenosis. This study reveals the effect of stenosis on the heat transfer and velocity of blood flowing in the constricted artery. The governing and energy equations are formulated in a cylindrical coordinate system. Hence, the set of equations and boundary conditions are solved numerically by Marker and Cell (MAC) method. The graphical result shows the profile of blood temperature is increased while the blood velocity is decreased at the critical height of stenosis.

  18. Relationship between preoperative radial artery and postoperative arteriovenous fistula blood flow in hemodialysis patients.

    Sato, Michiko; Io, Hiroaki; Tanimoto, Mitsuo; Shimizu, Yoshio; Fukui, Mitsumine; Hamada, Chieko; Horikoshi, Satoshi; Tomino, Yasuhiko

    2012-01-01

    It is recommended that arteriovenous fistula (AVF) blood flow should be more than 425 ml/min before cannulation. However, the relationship between preoperative radial artery flow (RAF) and postoperative AVF blood flow has still not been examined. Sixty-one patients with end-stage kidney disease (ESKD) were examined. They had an AVF prepared at Juntendo University Hospital from July 2006 through August 2007. Preoperative RAF and postoperative AVF blood flows were measured by ultrasonography. AVF blood flow gradually increased after the operation. AVF blood flow was significantly correlated with preoperative RAF. When preoperative RAF exceeded 21.4 ml/min, AVF blood flow rose to more than 425 ml/min. The postoperative AVF blood flow in the group with RAF of more than 20 ml/min was significantly higher than that in those with less than 20 ml/min. Preoperative RAF of less than 20 ml/min had a significantly high risk of primary AVF failure within 8 months compared with that of more than 20 ml/min. It appears that measurement of RAF by ultrasonography is useful for estimating AVF blood flow postoperatively and can predict the risk of complications in ESKD patients.

  19. A model for investigating the control of muscle blood flow: the masseteric artery in conscious rabbits

    Roatta, S; Mohammed, M; Turturici, M; Milano, L; Passatore, M

    2010-01-01

    The complex interplay of neural, metabolic, myogenic and mechanical mechanisms that regulate blood flow in skeletal muscle (MBF) is still incompletely understood. For the first time, a method is presented for high time-resolution recording of MBF from a purely muscular artery in physiological conditions. Ultrasound perivascular flow probes were implanted (n = 15) mono- or bilaterally around the masseteric branch of the facial artery in nine rabbits and tested up to 16 days after implant. Reliable and stable recordings were achieved in 50% of implants. Blood flow was observed to increase from a resting level of 0.2–0.3 ml min −1 up to 4.0–6.0 ml min −1 during spontaneous masticatory activity. In addition, within single masticatory cycles marked back flow transients could be observed (peak flow = −10 ml min −1 ) during powerful masticatory strokes but not during mild mastication. The possibility of (1) surgically removing the sympathetic supply to the relevant vascular bed and of (2) bilaterally monitoring the perfusion of masseter muscles thus allowing to use one side as control side for different types of interventions makes this model a useful tool for disentangling the different mechanisms involved in the control of MBF. (note)

  20. An efficient parallel simulation of unsteady blood flows in patient-specific pulmonary artery.

    Kong, Fande; Kheyfets, Vitaly; Finol, Ender; Cai, Xiao-Chuan

    2018-04-01

    Simulation of blood flows in the pulmonary artery provides some insight into certain diseases by examining the relationship between some continuum metrics, eg, the wall shear stress acting on the vascular endothelium, which responds to flow-induced mechanical forces by releasing vasodilators/constrictors. V. Kheyfets, in his previous work, studies numerically a patient-specific pulmonary circulation to show that decreasing wall shear stress is correlated with increasing pulmonary vascular impedance. In this paper, we develop a scalable parallel algorithm based on domain decomposition methods to investigate an unsteady model with patient-specific pulsatile waveforms as the inlet boundary condition. The unsteady model offers tremendously more information about the dynamic behavior of the flow field, but computationally speaking, the simulation is a lot more expensive since a problem which is similar to the steady-state problem has to be solved many times, and therefore, the traditional sequential approach is not suitable anymore. We show computationally that simulations using the proposed parallel approach with up to 10 000 processor cores can be obtained with much reduced compute time. This makes the technology potentially usable for the routine study of the dynamic behavior of blood flows in the pulmonary artery, in particular, the changes of the blood flows and the wall shear stress in the spatial and temporal dimensions. Copyright © 2017 John Wiley & Sons, Ltd.

  1. Central retinal vein occlusion with cilioretinal infarction from branch flow exclusion and choroidal arterial steal.

    McLeod, David

    2009-01-01

    The first definitive study of retinal vein occlusion complicated by infarction within the territory of one or more cilioretinal arteries was published in 1976. Many individual cases and further case series have been reported in the interim, but the nature of the interrelationship is still under debate. A review was undertaken of the relevant clinical and fundus fluorescein angiographic characteristics of this combined retinal vascular disorder together with the pathophysiological mechanisms currently presented in the literature to explain their association. Scientific publications up to 2008 were evaluated by one of the authors of the original report. There are broad similarities between publications in their descriptions of the clinical features, but significant differences of detail and interpretation are also evident. Most of the mechanisms so far proposed to account for cilioretinal infarction after central or hemisphere retinal vein occlusion do not withstand critical scrutiny. Two related hypotheses are expounded that appear to satisfactorily elucidate this interrelationship -- branch flow exclusion and branch flow diversion (otherwise termed "choroidal arterial steal"). In eyes with a cilioretinal supply, the probability that cilioretinal infarction will complicate retinal vein occlusion increases with increasing severity of venous obstruction and the more distally the cilioretinal artery arises from the posterior ciliary arterial tree. A distal branch point also facilitates observation of dye front reciprocation within the artery. Indicators of the degree of venous obstruction that may be necessary to instigate cilioretinal infarction include very prolonged dye transit times in the central retinal circulation, exaggerated venous cyanosis and tortuosity, perivenous cotton-wool sentinels, and macular perivenular whitening.

  2. Effect of low-dose radiation on ocular circulation

    Baba, Keiko; Hiroishi, Goro; Honda, Masae; Yoshikawa, Hiroshi; Fujisawa, Kimihiko; Ishibashi, Tatsuro

    1999-01-01

    We treated 6 eyes of unilateral age-related macular degeneration by low-dose radiation. Each eye received daily dose of 2 Gy by 4MV lineac totalling 20 Gy over 2 weeks. Color doppler flowmetry was used to determine the mean blood flow velocity (Vmean) and vascular resistive index (RI) in the short posterior ciliary artery, central retinal artery and ophthalmic artery in the treated and fellow eyes before and up to 6 months of treatment. There were no significant differences in Vmean and RI before and after treatment. The findings show the absence of apparent influence of low-dose radiation on the ocular circulation in age-related macular degeneration. (author)

  3. Effect of low-dose radiation on ocular circulation

    Baba, Keiko; Hiroishi, Goro; Honda, Masae; Yoshikawa, Hiroshi; Fujisawa, Kimihiko; Ishibashi, Tatsuro [Kyushu Univ., Fukuoka (Japan). Faculty of Medicine

    1999-05-01

    We treated 6 eyes of unilateral age-related macular degeneration by low-dose radiation. Each eye received daily dose of 2 Gy by 4MV lineac totalling 20 Gy over 2 weeks. Color doppler flowmetry was used to determine the mean blood flow velocity (Vmean) and vascular resistive index (RI) in the short posterior ciliary artery, central retinal artery and ophthalmic artery in the treated and fellow eyes before and up to 6 months of treatment. There were no significant differences in Vmean and RI before and after treatment. The findings show the absence of apparent influence of low-dose radiation on the ocular circulation in age-related macular degeneration. (author)

  4. Effect of perturbations and a meal on superior mesenteric artery flow in patients with orthostatic hypotension

    Fujimura, J.; Camilleri, M.; Low, P. A.; Novak, V.; Novak, P.; Opfer-Gehrking, T. L.

    1997-01-01

    Our aims were to evaluate to role of superior mesenteric blood flow in the pathophysiology of orthostatic hypotension in patients with generalized autonomic failure. METHODS: Twelve patients with symptomatic neurogenic orthostatic hypotension and 12 healthy controls underwent superior mesenteric artery flow measurements using Doppler ultrasonography during head-up tilt and tilt plus meal ingestion. Autonomic failure was assessed using standard tests of the function of the sympathetic adrenergic, cardiovagal and postganglionic sympathetic sudomotor function. RESULTS: Superior mesenteric flow volume and time-averaged velocity were similar in patients and controls at supine rest; however, responses to cold pressor test and upright tilt were attenuated (p stress can be significantly attenuated by reducing the splanchnic-mesenteric volume increase in response to food. Evaluation of mesenteric flow in response to eating and head-up tilt provide important information on intra-abdominal sympathetic adrenergic function, and the ability of the patient to cope with orthostatic stress.

  5. Stent-induced flow disturbances in the ipsilateral external carotid artery following internal carotid artery stenting: a temporary cause of jaw claudication.

    Giurgea, Georgiana-Aura; Haumer, Markus; Mlekusch, Irene; Sabeti-Sandor, Schila; Dick, Petra; Schillinger, Martin; Minar, Erich; Mlekusch, Wolfgang

    2017-07-01

    We hypothesize that stenting of the internal carotid artery can immediately impede blood flow to the external carotid artery by either plaque shift or stent coverage of the ostium, and thereby cause ischemic symptoms like ipsilateral jaw claudication. Thirty-three patients with high-grade asymptomatic stenosis of the internal carotid artery who underwent endovascular treatment were examined by ultrasound of the external carotid artery and performed an exercise test by chewing chewing gum synchronously to an electronic metronome for 3 min. Tests were performed before, the day after, and 1 week after the stenting procedure. Claudication time was defined as the timespan until occurrence of pain of the masseter muscle and/or chewing dyssynchrony to the metronome for more than 15 s. Ten patients with an isolated, atherosclerotic stenosis of the external carotid artery served as controls. A significantly reduced claudication time (in seconds) was recorded in patients who underwent carotid artery stenting compared to baseline values; median 89 (interquartile range, IQR, 57 to 124) vs. median 180 (IQR 153 to 180; p external carotid artery into faster or slower as 200 cm/sec, the effect was even accentuated. Stenting values showed improvement 1 week after but did not return to baseline levels. No respective changes were found in controls. Stenting of the internal carotid artery lead to ipsilateral flow deterioration at the external carotid artery resulting in temporary jaw claudication. This impairment attenuated over the time and was significantly reduced after 1 week.

  6. Evaluation of blood flow in Allograft Renal Arteries anastomosed with two different techniques

    Zomorrodi, A.; Bohluli, A.; Tarzamany, M.K.

    2008-01-01

    Renal artery stenosis in renal transplantation (TRAS) is an avoidable short or long term surgical complication. The etiology is multifactorial, but faulty anastomosis is a major factor. In our transplant center, we evaluated the incidence of TRAS with the use of two different suturing techniques of the anastomosis site between allograft renal and renal and iliac arteries in two groups of renal transplant recipients, group A: 14 patients (6 males and 8 females with age 16 to 59 and mean age of 38 years) in whom allograft arteries were anastomosed with a continuous suture technique and group B: 14 patients (7 males and 7 females with age 32 to 61 and mean age of 46.6 years) in whom the allograft arteries were anastomosed with a combined suture technique (continuous and uninterrupted. Post transplantation, the velocity of blood flow in the renal and iliac arteries at the site of anastomosis was measured by color Doppler ultrasound. The ultrasonographer was blinded to the surgical technique in both study groups. The ratio of the maximum velocity of blood at the site of anastomosis to that in the iliac artery of less than 2.5 was considered as non-significant stenosis, while a ratio of more than 2.5 was considered significant stenosis. In group A there were 9 cases of non-significant stenosis in comparison to 3 cases in group B, while there were no cases of significant stenosis in group A in comparison to 3 cases in group B; the difference was not statistically significant. We conclude that there was no difference in the compared surgical techniques of anastomosis in our study groups. This suggests that other factors such as gentle handling of tissue, enough spatula, margin reversion and comparable diameter of the anastomosed vessels may be more important in the prevention of renal allograft stenosis than the type of suture technique. (author)

  7. Pulse waveform analysis on temporal changes in ocular blood flow due to caffeine intake: a comparative study between habitual and non-habitual groups.

    Ismail, Aishah; Bhatti, Mehwish S; Faye, Ibrahima; Lu, Cheng Kai; Laude, Augustinus; Tang, Tong Boon

    2018-06-06

    To evaluate and compare the temporal changes in pulse waveform parameters of ocular blood flow (OBF) between non-habitual and habitual groups due to caffeine intake. This study was conducted on 19 healthy subjects (non-habitual 8; habitual 11), non-smoking and between 21 and 30 years of age. Using laser speckle flowgraphy (LSFG), three areas of optical nerve head were analyzed which are vessel, tissue, and overall, each with ten pulse waveform parameters, namely mean blur rate (MBR), fluctuation, skew, blowout score (BOS), blowout time (BOT), rising rate, falling rate, flow acceleration index (FAI), acceleration time index (ATI), and resistive index (RI). Two-way mixed ANOVA was used to determine the difference between every two groups where p groups in several ocular pulse waveform parameters, namely MBR (overall, vessel, tissue), BOT (overall), rising rate (overall), and falling rate (vessel), all with p group, but not within the habitual group. The temporal changes in parameters MBR (vessel, tissue), skew (overall, vessel), BOT (overall, vessel), rising rate (overall), falling rate (overall, vessel), and FAI (tissue) were significant for both groups (habitual and non-habitual) in response to caffeine intake. The experiment results demonstrated caffeine does modulate OBF significantly and response differently in non-habitual and habitual groups. Among all ten parameters, MBR and BOT were identified as the suitable biomarkers to differentiate between the two groups.

  8. [Evaluation and Optimization of Microvascular Arterial Anastomoses by Transit Time Flow Measurement].

    Herberhold, S; Röttker, J; Bartmann, D; Solbach, A; Keiner, S; Welz, A; Bootz, F; Laffers, W

    2016-03-01

    INDRODUCTION: The regular application of transit time flow measurement in microvascular anastomoses during heart surgery has lead to improvements of the outcome of coronary artery bypass grafts. Our study was meant to discover whether this measurement method was also applicable for evaluation and optimization of microvascular arterial anastomoses of radial forearm flaps. In this prospective examination a combining ultrasound imaging and transit time flow measurement device (VeriQ, MediStim) was used during surgery to assess anastomotic quality of 15 radial forearm flaps. Pulsatility index (PI) and mean blood flow were measured immediately after opening the arterial anastomosis as well as 15 min afterwards. Furthermore, application time and description of handling were recorded seperately for every assessment. Mean blood flow immediately after opening the anastomosis and 15 min later were 3.9 and 3.4 ml/min resepectively showing no statistically significant difference (p=0.96). There was no significance in the increase of pulsatility index from 22.1 to 27.2 (p=0.09) during the same time range, either. Due to measurement results showing atypical pulse curves in 2 cases decision for surgical revision of the anastomoses was made. All forearm flaps showed good vascularisation during follow-up. Time for device set up, probe placement and measurements was about 20 min. Handling was described to be uncomplicated without exception. There were no noteworthy problems. Transit time flow measurement contributes to the improvement of anastomotic quality and therefore to the overall outcome of radial forearm flaps. The examined measurement method provides objective results and is useful for documentation purposes. © Georg Thieme Verlag KG Stuttgart · New York.

  9. Blood flow quantification from 2D phase contrast MRI in renal arteries using an unsupervised data driven approach

    Zoellner, Frank Gerrit [Computer Assisted Clinical Medicine, Faculty of Medicine Mannheim, Univ. of Heidelberg, Mannheim (Germany); Section for Radiology, Dept. of Surgical Sciences, Univ. of Bergen (Norway); Monssen, Jan Ankar [Dept. of Radiology, Haukeland Univ. Hospital, Bergen (Norway); Roervik, Jarie [Section for Radiology, Dept. of Surgical Sciences, Univ. of Bergen (Norway); Dept. of Radiology, Haukeland Univ. Hospital, Bergen (Norway); Lundervold, Arvid [Dept. of Radiology, Haukeland Univ. Hospital, Bergen (Norway); Dept. of Biomedicine, Univ. of Bergen (Norway); Schad, Lothar R. [Computer Assisted Clinical Medicine, Faculty of Medicine Mannheim, Univ. of Heidelberg, Mannheim (Germany)

    2009-07-01

    We present a clustering approach to segment the renal artery from 2D PC Cine MR images to measure arterial blood velocity and flow. Such information is important in grading renal artery stenosis and to support the decision on surgical interventions like percutaneous transluminal angioplasty. Results from 20 data sets (volunteers, 7 patients) show that the renal arteries could be extracted automatically and the corresponding velocity profiles were close (r = 0.977) to that obtained by manual delineations of the vessel areas. (orig.)

  10. Blood flow quantification from 2D phase contrast MRI in renal arteries using an unsupervised data driven approach

    Zoellner, Frank Gerrit; Monssen, Jan Ankar; Roervik, Jarie; Lundervold, Arvid; Schad, Lothar R.

    2009-01-01

    We present a clustering approach to segment the renal artery from 2D PC Cine MR images to measure arterial blood velocity and flow. Such information is important in grading renal artery stenosis and to support the decision on surgical interventions like percutaneous transluminal angioplasty. Results from 20 data sets (volunteers, 7 patients) show that the renal arteries could be extracted automatically and the corresponding velocity profiles were close (r = 0.977) to that obtained by manual delineations of the vessel areas. (orig.)

  11. Marked Increase in Flow Velocities During Deep Expiration: A Duplex Doppler Sign of Celiac Artery Compression Syndrome

    Erden, Ayse; Yurdakul, Mehmet; Cumhur, Turhan

    1999-01-01

    Symptoms of chronic mesenteric ischemia develop when the celiac artery is constricted by the median arcuate ligament of the diaphragm. Lateral aortography is the primary modality for diagnosing ligamentous compression of the celiac artery. However, duplex Doppler sonography performed during deep expiration can cause a marked increase in flow velocities at the compressed region of the celiac artery and suggest the diagnosis of celiac arterial constriction due to the diaphragmatic ligament. RID='''' ID='''' Correspondence to: A. Erden, M.D., Hafta sokak. 23/6, Gaziosmanpasa, 06700 Ankara, Turkey

  12. [Evaluation of the arterial blood flow parameters in the eye of myopic patients].

    Mrugacz, Małgorzata; Bryl, Anna

    2013-04-01

    Myopia is a common refractive defect. Has a good vision from near and deterioration of vision with increasing distance. The main reason for its occurrence is too long axis of the eyeball. The consequence of elongation of the eyeball is the development of degenerative changes in the retina. Despite much research has failed to clearly identify the causes of degenerative changes in those short-sighted. The aim of the study was to evaluate the maximum and minimum speed in arterial blood vessels of the eye in people with myopia. The study included 70 patients (138 eyes), 53 women and 17 men, aged from 18 to 79 years, with myopia of -0.25 to -18.0 Dsph and length of the eyeball from 22.61 to 33.36 mm. Depending on the kind and the degree of the progress of degenerative changes, patients were divided in 4 groups: I - without degenerative changes on the fundus (n=32; K-23, M-9); II- with the short-sighted sickle (n=20; K-14, M-6); Ill - with the structure thinned down of the retina, accompanying the short-sighted sickle (n = 8; K-6, M-2); IV - with extensive choroidal-retina disappearances in the fundus (n = 10; K-7, M-3). In all individuals enrolled underwent Color Doppler ultrasound with apparatus SSA 770A Toshiba Aplio with linear probe frequency 12 MHz, judging maximum (Vmax) and minimum (Vmin) speed in the arteries of the eye: ophthalmic artery (OA), central retinal artery (CRA) and short posterior ciliary arteries (SPCA) located on the nasal and temporal side of the optic disc. The results were statistically analyzed. No statistically significant relationship between the nature of degenerative changes of the eye, and blood velocity in the OA. There was a increase in Vmax and Vmin blood in OA in Group IV, but these changes were not statistically significant. Statistically significant correlation was observed while in the CRA. With a decrease in Vmax and Vmin of blood flowing through a vessel exacerbation of retinal degeneration. Vmax and Vmin changes in the blood did

  13. Stability of Carotid Artery Under Steady-State and Pulsatile Blood Flow: A Fluid–Structure Interaction Study

    Saeid Khalafvand, Seyed; Han, Hai-Chao

    2015-01-01

    It has been shown that arteries may buckle into tortuous shapes under lumen pressure, which in turn could alter blood flow. However, the mechanisms of artery instability under pulsatile flow have not been fully understood. The objective of this study was to simulate the buckling and post-buckling behaviors of the carotid artery under pulsatile flow using a fully coupled fluid–structure interaction (FSI) method. The artery wall was modeled as a nonlinear material with a two-fiber strain-energy function. FSI simulations were performed under steady-state flow and pulsatile flow conditions with a prescribed flow velocity profile at the inlet and different pressures at the outlet to determine the critical buckling pressure. Simulations were performed for normal (160 ml/min) and high (350 ml/min) flow rates and normal (1.5) and reduced (1.3) axial stretch ratios to determine the effects of flow rate and axial tension on stability. The results showed that an artery buckled when the lumen pressure exceeded a critical value. The critical mean buckling pressure at pulsatile flow was 17–23% smaller than at steady-state flow. For both steady-state and pulsatile flow, the high flow rate had very little effect (<5%) on the critical buckling pressure. The fluid and wall stresses were drastically altered at the location with maximum deflection. The maximum lumen shear stress occurred at the inner side of the bend and maximum tensile wall stresses occurred at the outer side. These findings improve our understanding of artery instability in vivo. PMID:25761257

  14. Stability of carotid artery under steady-state and pulsatile blood flow: a fluid-structure interaction study.

    Saeid Khalafvand, Seyed; Han, Hai-Chao

    2015-06-01

    It has been shown that arteries may buckle into tortuous shapes under lumen pressure, which in turn could alter blood flow. However, the mechanisms of artery instability under pulsatile flow have not been fully understood. The objective of this study was to simulate the buckling and post-buckling behaviors of the carotid artery under pulsatile flow using a fully coupled fluid-structure interaction (FSI) method. The artery wall was modeled as a nonlinear material with a two-fiber strain-energy function. FSI simulations were performed under steady-state flow and pulsatile flow conditions with a prescribed flow velocity profile at the inlet and different pressures at the outlet to determine the critical buckling pressure. Simulations were performed for normal (160 ml/min) and high (350 ml/min) flow rates and normal (1.5) and reduced (1.3) axial stretch ratios to determine the effects of flow rate and axial tension on stability. The results showed that an artery buckled when the lumen pressure exceeded a critical value. The critical mean buckling pressure at pulsatile flow was 17-23% smaller than at steady-state flow. For both steady-state and pulsatile flow, the high flow rate had very little effect (<5%) on the critical buckling pressure. The fluid and wall stresses were drastically altered at the location with maximum deflection. The maximum lumen shear stress occurred at the inner side of the bend and maximum tensile wall stresses occurred at the outer side. These findings improve our understanding of artery instability in vivo.

  15. Defining the Collateral Flow of Posterior Tibial Artery and Dorsalis Pedis Artery in Ischemic Foot Disease: Is It a Preventing Factor for Ischemia?

    Tutar, Onur; Yildirim, Duzgun; Samanci, Cesur; Rafiee, Babak; Inan, Kaan; Dikici, Suleyman; Ustabasioglu, Fethi Emre; Kuyumcu, Gokhan

    2016-01-01

    Critical limb ischemia, a worldwide prevalent morbidity cause, is mostly secondary to vascular insufficiency due to atherosclerosis. The disease presents with intermittent claudication, which can progress to critical limb ischemia requiring amputation. Research has emphasized that the quality or existence of the pedal arch have a direct effect on wound healing and, therefore, on limb salvage, through the mechanism of collateral vascularization to the ischemic regions. This study aimed to determine the existence and, if present, grade of retrograde blood flow from plantar arch to dorsal foot artery (dorsalis pedis artery, DPA). The correlation between clinical symptoms and presence of collateral flow were also investigated. Study group consisted of 34 cases, which included patient group (n = 17, all male, mean age: 68 years) and control group (n = 17, all male, mean age: 66 years). After physical examination and lower extremity Doppler examination, spectral morphology of DPA flow was recorded, before and during manual compression of posterior tibial artery (PTA), for a period of 5 seconds. At the end, findings of Doppler ultrasound, computed tomography angiography, magnetic resonance angiography and, physical examination finding and symptomatology were gathered and analyzed. In the patient group, 31 lower limb arteries, of total of 17 cases, were included. After compression maneuver, DPA in 11 cases (six right, five left) showed retrograde filling from plantar arch. This retrograde flow support was triphasic in three cases, biphasic in five cases, and monophasic in three cases. In other DPAs of these 20 limbs, PTA based retrograde collateral flow was not determined. In nine of these 20 limbs, with no or diminished retrograde filling, symptoms were worse than in other cases. Contrarily, only two of 11 limbs, with retrograde collaterals, have claudication during walking. In cases with critical atherosclerotic disease of anterior tibial artery, PTA-based biphasic or

  16. Role of Doppler ultrasonography evaluation of superior mesenteric artery flow volume in the assessment of Crohn's disease activity

    Fabiana Paiva Martins

    2013-09-01

    Full Text Available Objective To investigate superior mesenteric artery flow measurement by Doppler ultrasonography as a means of characterizing inflammatory activity in Crohn's disease. Materials and Methods Forty patients were examined and divided into two groups – disease activity and remission – according to their Crohn's disease activity index score. Mean superior mesenteric artery flow volume was calculated for each group and correlated with Crohn's disease activity index score. Results The mean superior mesenteric artery flow volume was significantly greater in the patients with active disease (626 ml/min ± 236 × 376 ml/min ± 190; p = 0.001. As a cut off corresponding to 500 ml/min was utilized, the superior mesenteric artery flow volume demonstrated sensitivity of 83% and specificity of 82% for the diagnosis of Crohn's disease activity. Conclusion The present results suggest that patients with active Crohn's disease have increased superior mesenteric artery flow volume as compared with patients in remission. Superior mesenteric artery flow measurement had a good performance in the assessment of disease activity in this study sample.

  17. Determinants of leptomeningeal collateral flow in stroke patients with a middle cerebral artery occlusion

    Seeters, Tom van; Velthuis, Birgitta K.; Biessels, Geert Jan; Kappelle, L.J.; Graaf, Yolanda van der

    2016-01-01

    Poor leptomeningeal collateral flow is related to worse clinical outcome in acute ischemic stroke, but the factors that determine leptomeningeal collateral patency are largely unknown. We explored the determinants of leptomeningeal collateral flow and assessed their effect on the relation between leptomeningeal collateral flow and clinical outcome. We included 484 patients from the Dutch acute stroke study (DUST) with a middle cerebral artery (MCA) occlusion. The determinants of poor leptomeningeal collateral flow (≤50 % collateral filling) were identified with logistic regression. We calculated the relative risk (RR) of poor leptomeningeal collateral flow in relation to poor clinical outcome (90-day modified Rankin Scale 3-6) using Poisson regression and assessed whether the determinants of leptomeningeal collateral flow affected this relation. Leptomeningeal collateral flow was poor in 142 patients (29 %). In multivariable analyses, higher admission glucose level (odds ratio (OR) 1.1 per mmol/L increase (95 % CI 1.0-1.2)), a proximal MCA occlusion (OR 1.9 (95 % CI 1.3-3.0)), and an incomplete posterior circle of Willis (OR 1.7 (95 % CI 1.1-2.6)) were independently related to poor leptomeningeal collateral flow. Poor leptomeningeal collateral flow was related to poor clinical outcome (unadjusted RR 1.7 (95 % CI 1.4-2.0)), and this relation was not affected by the determinants of leptomeningeal collateral flow. Our study shows that admission glucose level, a proximal MCA occlusion, and an incomplete ipsilateral posterior circle of Willis are determinants of leptomeningeal collateral flow that represent a combination of congenital, acquired, and acute factors. After adjustment for these determinants, leptomeningeal collateral flow remains related to clinical outcome. (orig.)

  18. Determinants of leptomeningeal collateral flow in stroke patients with a middle cerebral artery occlusion

    Seeters, Tom van; Velthuis, Birgitta K. [University Medical Center Utrecht, Department of Radiology, Utrecht (Netherlands); Biessels, Geert Jan; Kappelle, L.J. [University Medical Center Utrecht, Department of Neurology, Brain Center Rudolf Magnus, Utrecht (Netherlands); Graaf, Yolanda van der [University Medical Center Utrecht, Julius Center for Health Sciences and Primary Care, Utrecht (Netherlands); Collaboration: on behalf of the Dutch acute stroke study (DUST) investigators

    2016-10-15

    Poor leptomeningeal collateral flow is related to worse clinical outcome in acute ischemic stroke, but the factors that determine leptomeningeal collateral patency are largely unknown. We explored the determinants of leptomeningeal collateral flow and assessed their effect on the relation between leptomeningeal collateral flow and clinical outcome. We included 484 patients from the Dutch acute stroke study (DUST) with a middle cerebral artery (MCA) occlusion. The determinants of poor leptomeningeal collateral flow (≤50 % collateral filling) were identified with logistic regression. We calculated the relative risk (RR) of poor leptomeningeal collateral flow in relation to poor clinical outcome (90-day modified Rankin Scale 3-6) using Poisson regression and assessed whether the determinants of leptomeningeal collateral flow affected this relation. Leptomeningeal collateral flow was poor in 142 patients (29 %). In multivariable analyses, higher admission glucose level (odds ratio (OR) 1.1 per mmol/L increase (95 % CI 1.0-1.2)), a proximal MCA occlusion (OR 1.9 (95 % CI 1.3-3.0)), and an incomplete posterior circle of Willis (OR 1.7 (95 % CI 1.1-2.6)) were independently related to poor leptomeningeal collateral flow. Poor leptomeningeal collateral flow was related to poor clinical outcome (unadjusted RR 1.7 (95 % CI 1.4-2.0)), and this relation was not affected by the determinants of leptomeningeal collateral flow. Our study shows that admission glucose level, a proximal MCA occlusion, and an incomplete ipsilateral posterior circle of Willis are determinants of leptomeningeal collateral flow that represent a combination of congenital, acquired, and acute factors. After adjustment for these determinants, leptomeningeal collateral flow remains related to clinical outcome. (orig.)

  19. Pseudonormalization of transmitral flow pattern during exercise thallium-201 imaging in patients with coronary artery disease

    Shiota, Takahiro; Sakamoto, Tsuguya; Takenaka, Katsu; Amano, Keiko; Amano, Wataru; Igarashi, Tsutomu; Otake, Takeshi; Sugimoto, Tsuneaki

    1993-01-01

    This study was undertaken to assess the usefulness of Doppler parameters and transmitral blood velocity for detecting abnormalities of left ventricular diastolic function during low-level exercise thallium-201 imaging. The study population consisted of 16 thallium perfusion defect patients with coronary artery disease (mean 61±8 years) and 21 age-matched control subjects (mean 55±5 years) without any thallium perfusion defect. Of the 16 thallium perfusion defect patients, 12 were examined by coronary arteriography, of whom single vessel coronary artery disease was seen in 2 and multivessel coronary artery disease in 10. Patients with mitral regurgitant murmurs were excluded from the study. Peak mitral blood flow velocity was measured in early diastole (E) and during atrial systole (A) and the A/E ratio was calculated. The changes in blood pressure and heart rate after low-level exercise were not significantly different between control and thallium perfusion defect groups. The A/E ratio increased slightly in control subjects from 93±14% at baseline to 100±15% during low-level exercise (p<0.05), whereas in patients with thallium perfusion defect, it decreased significantly from 119±33% at baseline to 92±23% during low-level exercise (p<0.01). Thus pseudonormalization of the A/E ratio during low-level exercise may be valuable in the evaluation of patients with severe or multivessel coronary artery disease. (author)

  20. Quantitative Real-Time Fluoroscopy Analysis on Measurement of the Hepatic Arterial Flow During Transcatheter Arterial Chemoembolization of Hepatocellular Carcinoma: Comparison with Quantitative Digital Subtraction Angiography Analysis

    Lin, Yi-Yang; Lee, Rheun-Chuan, E-mail: rclee@vghtpe.gov.tw; Guo, Wan-Yuo, E-mail: wyguo@vghtpe.gov.tw; Chu, Wei-Fa [Taipei Veterans General Hospital, Department of Radiology (China); Wu, Frank Chun-Hsien [Siemens Healthcare Ltd. (China); Gehrisch, Sonja [Siemens Healthcare GmbH (Germany)

    2016-11-15

    PurposeTo quantify the arterial flow change during transcatheter arterial chemoembolization (TACE) for hepatocellular carcinoma (HCC) using digital subtraction angiography, quantitative color-coding analysis (d-QCA), and real-time subtraction fluoroscopy QCA (f-QCA).Materials and MethodsThis prospective study enrolled 20 consecutive patients with HCC who had undergone TACE via a subsegmental approach between February 2014 and April 2015. The TACE endpoint was a sluggish antegrade tumor-feeding arterial flow. d-QCA and f-QCA were used for determining the relative maximal density time (rT{sub max}) of the selected arteries. The rT{sub max} of the selected arteries was analyzed in d-QCA and f-QCA before and after TACE, and its correlation in both analyses was evaluated.ResultsThe pre- and post-TACE rT{sub max} of the embolized segmental artery in d-QCA and f-QCA were 1.59 ± 0.81 and 2.97 ± 1.80 s (P < 0.001) and 1.44 ± 0.52 and 2.28 ± 1.02 s (P < 0.01), respectively. The rT{sub max} of the proximal hepatic artery did not significantly change during TACE in d-QCA and f-QCA. The Spearman correlation coefficients of the pre- and post-TACE rT{sub max} of the embolized segmental artery between d-QCA and f-QCA were 0.46 (P < 0.05) and 0.80 (P < 0.001). Radiation doses in one series of d-QCA and f-QCA were 140.7 ± 51.5 milligray (mGy) and 2.5 ± 0.7 mGy, respectively.Conclusionsf-QCA can quantify arterial flow changes with a higher temporal resolution and lower radiation dose. Flow quantification of the embolized segmental artery using f-QCA and d-QCA is highly correlated.

  1. Quantitative Real-Time Fluoroscopy Analysis on Measurement of the Hepatic Arterial Flow During Transcatheter Arterial Chemoembolization of Hepatocellular Carcinoma: Comparison with Quantitative Digital Subtraction Angiography Analysis

    Lin, Yi-Yang; Lee, Rheun-Chuan; Guo, Wan-Yuo; Chu, Wei-Fa; Wu, Frank Chun-Hsien; Gehrisch, Sonja

    2016-01-01

    PurposeTo quantify the arterial flow change during transcatheter arterial chemoembolization (TACE) for hepatocellular carcinoma (HCC) using digital subtraction angiography, quantitative color-coding analysis (d-QCA), and real-time subtraction fluoroscopy QCA (f-QCA).Materials and MethodsThis prospective study enrolled 20 consecutive patients with HCC who had undergone TACE via a subsegmental approach between February 2014 and April 2015. The TACE endpoint was a sluggish antegrade tumor-feeding arterial flow. d-QCA and f-QCA were used for determining the relative maximal density time (rT_m_a_x) of the selected arteries. The rT_m_a_x of the selected arteries was analyzed in d-QCA and f-QCA before and after TACE, and its correlation in both analyses was evaluated.ResultsThe pre- and post-TACE rT_m_a_x of the embolized segmental artery in d-QCA and f-QCA were 1.59 ± 0.81 and 2.97 ± 1.80 s (P < 0.001) and 1.44 ± 0.52 and 2.28 ± 1.02 s (P < 0.01), respectively. The rT_m_a_x of the proximal hepatic artery did not significantly change during TACE in d-QCA and f-QCA. The Spearman correlation coefficients of the pre- and post-TACE rT_m_a_x of the embolized segmental artery between d-QCA and f-QCA were 0.46 (P < 0.05) and 0.80 (P < 0.001). Radiation doses in one series of d-QCA and f-QCA were 140.7 ± 51.5 milligray (mGy) and 2.5 ± 0.7 mGy, respectively.Conclusionsf-QCA can quantify arterial flow changes with a higher temporal resolution and lower radiation dose. Flow quantification of the embolized segmental artery using f-QCA and d-QCA is highly correlated.

  2. Functional assessment of sequential coronary artery fistula and coronary artery stenosis with fractional flow reserve and stress adenosine myocardial perfusion imaging

    Kuan Leong Yew

    2015-10-01

    Full Text Available Coronary artery fistula is an abnormal connection between one coronary artery to another coronary artery or cardiac chambers. The coronary artery fistula may cause significant shunting of blood and cause “pseudo-stenosis” or “steal phenomenon”. This will also accentuate pre-existing mild-moderate de novo coronary lesions with resultant greater pressure gradient difference across the lesions. Thus, fractional flow reserve can be a useful tool to guide intervention decision on the coronary artery fistula. There are very few published reports regarding the use of FFR to assess coronary artery fistula. In fact, there is no outcome data regarding the deferment of coronary artery fistula intervention when the FFR is not physiologically significant. This case highlighted the use of FFR to evaluate the functional significance of coronary fistula in the setting of ischemia evaluation and it was proven to be safe to defer intervention with good 3 year clinical outcome. Stress adenosine myocardial perfusion imaging correlated with the FFR result.

  3. Correlation between vortices and wall shear stress in a curved artery model under pulsatile flow conditions

    Cox, Christopher; Plesniak, Michael W.

    2017-11-01

    One of the most physiologically relevant factors within the cardiovascular system is the wall shear stress. The wall shear stress affects endothelial cells via mechanotransduction and atherosclerotic regions are strongly correlated with curvature and branching in the human vasculature, where the shear stress is both oscillatory and multidirectional. Also, the combined effect of curvature and pulsatility in cardiovascular flows produces unsteady vortices. In this work, our goal is to assess the correlation between multiple vortex pairs and wall shear stress. To accomplish this, we use an in-house high-order flux reconstruction Navier-Stokes solver to simulate pulsatile flow of a Newtonian blood-analog fluid through a rigid 180° curved artery model. We use a physiologically relevant flow rate and generate results using both fully developed and uniform entrance conditions, the latter motivated by the fact that flow upstream to a curved artery may not be fully developed. Under these two inflow conditions, we characterize the evolution of various vortex pairs and their subsequent effect on several wall shear stress metrics. Supported by GW Center for Biomimetics and Bioinspired Engineering.

  4. Ideal Internal Carotid Artery Trapping Technique without Bypass in a Patient with Insufficient Collateral Flow.

    Chung, Joon Ho; Shin, Yong Sam; Lim, Yong Cheol; Park, Minjung

    2009-04-01

    Internal carotid artery (ICA) trapping can be used for treating intracranial giant aneurysm, blood blister-like aneurysms and ICA rupture during the surgery. We present a novel ICA trapping technique which can be used with insufficient collaterals flow via anterior communicating artery (AcoA) and posterior communicating artery (PcoA). A patient was admitted with severe headache and the cerebral angiography demonstrated a typical blood blister-like aneurysm at the contralateral side of PcoA. For trapping the aneurysm, the first clip was placed at the ICA just proximal to the aneurysm whereas the distal clip was placed obliquely proximal to the origin of the PcoA to preserve blood flow from the PcoA to the distal ICA. The patient was completely recovered with good collaterals filling to the right ICA territories via AcoA and PcoA. This technique may be an effective treatment option for trapping the aneurysm, especially when the PcoA preservation is mandatory.

  5. The effect of intravitreal bevacizumab on ocular blood flow in diabetic retinopathy and branch retinal vein occlusion as measured by laser speckle flowgraphy

    Nitta F

    2014-06-01

    Full Text Available Fumihiko Nitta,1 Hiroshi Kunikata,1,2 Naoko Aizawa,1 Kazuko Omodaka,1 Yukihiro Shiga,1 Masayuki Yasuda,1 Toru Nakazawa1–31Department of Ophthalmology, Tohoku University Graduate School of Medicine, Sendai, Japan; 2Department of Retinal Disease Control, Tohoku University Graduate School of Medicine, Sendai, Japan; 3Department of Advanced Ophthalmic Medicine, Tohoku University Graduate School of Medicine, Sendai, JapanBackground: This study evaluated the effect of intravitreal injection of bevacizumab (IVB on macular edema associated with diabetic retinopathy (DME or branch retinal vein occlusion (BRVOME using laser speckle flowgraphy.Methods: A comparative interventional study of 25 eyes from 22 patients with macular edema (DME group: 12 eyes; BRVOME group: 13 eyes who underwent IVB. Mean blur rate (MBR was measured in the retinal artery, retinal vein, optic nerve head (ONH, and choroid before and after IVB. Results: In the BRVOME group, there was no significant change in MBR in the retinal artery, retinal vein or ONH, but choroidal MBR decreased significantly (P=0.04. In the DME group, the MBR in the retinal artery, retinal vein, ONH, and choroid decreased significantly (P=0.02, P=0.04, P<0.001, and P=0.04, respectively. In the DME group, pre-IVB MBR in the ONH was significantly correlated with post-IVB foveal thickness (R= -0.71, P=0.002. There was no such correlation in the BRVOME group in the ONH.Conclusion: IVB had a suppressive effect on circulation in eyes with DME but not in those with BRVOME. This suggests that this noninvasive and objective biomarker may be a useful part of pre-IVB evaluations and decision-making in DME.Keywords: macular edema, mean blur rate, optic nerve head, biomarker, ocular circulation

  6. Flow Velocities After Carotid Artery Stenting: Impact of Stent Design. A Fluid Dynamics Study in a Carotid Artery Model with Laser Doppler Anemometry

    Greil, Oliver; Kleinschmidt, Thomas; Weiss, Wolfgang; Wolf, Oliver; Heider, Peter; Schaffner, Silvio; Gianotti, Marc; Schmid, Thomas; Liepsch, Dieter; Berger, Hermann

    2005-01-01

    Purpose. To study the influence of a newly developed membrane stent design on flow patterns in a physiologic carotid artery model. Methods. Three different stents were positioned in silicone models of the carotid artery: a stainless steel stent (Wall-stent), a nitinol stent (SelfX), and a nitinol stent with a semipermeable membrane (MembraX). To increase the contact area of the membrane with the vessel wall, another MembranX model was modified at the outflow tract. The membrane consists of a biocompatible silicone-polyurethane copolymer (Elast-Eon) with a pore size of 100 μm. All stents were deployed across the bifurcation and the external carotid artery origin. Flow velocity measurements were performed with laser Doppler anemometry (LDA), using pulsatile flow conditions (Re = 220; flow 0.39 l/min; flow rate ratio ICA:ECA = 70:30) in hemodynamically relevant cross-sections. The hemodynamic changes were analyzed by comparing velocity fluctuations of corresponding flow profiles. Results. The flow rate ratio ICA:ECA shifted significantly from 70/30 to 73.9/26.1 in the MembraX and remained nearly unchanged in the SelfX and Wallstent. There were no changes in the flow patterns at the inflow proximal to the stents. In the stent no relevant changes were found in the SelfX. In the Wallstent the separation zone shifted from the orifice of the ICA to the distal end of the stent. Four millimeters distal to the SelfX and the Wallstent the flow profile returned to normal. In the MembraX an increase in the central slipstreams was found with creation of a flow separation distal to the stent. With a modification of the membrane this flow separation vanished. In the ECA flow disturbances were seen at the inner wall distal to the stent struts in the SelfX and the Wallstent. With the MembraX a calming of flow could be observed in the ECA with a slight loss of flow volume. Conclusions. Stent placement across the carotid artery bifurcation induces alterations of the physiologic flow

  7. Tomographic particle image velocimetry investigation of the flow in a modeled human carotid artery bifurcation

    Buchmann, N. A.; Atkinson, C.; Jeremy, M. C.; Soria, J.

    2011-04-01

    Hemodynamic forces within the human carotid artery are well known to play a key role in the initiation and progression of vascular diseases such as atherosclerosis. The degree and extent of the disease largely depends on the prevailing three-dimensional flow structure and wall shear stress (WSS) distribution. This work presents tomographic PIV (Tomo-PIV) measurements of the flow structure and WSS in a physiologically accurate model of the human carotid artery bifurcation. The vascular geometry is reconstructed from patient-specific data and reproduced in a transparent flow phantom to demonstrate the feasibility of Tomo-PIV in a complex three-dimensional geometry. Tomographic reconstruction is performed with the multiplicative line-of-sight (MLOS) estimation and simultaneous multiplicative algebraic reconstruction (SMART) technique. The implemented methodology is validated by comparing the results with Stereo-PIV measurements in the same facility. Using a steady flow assumption, the measurement error and RMS uncertainty are directly inferred from the measured velocity field. It is shown that the measurement uncertainty increases for increasing light sheet thickness and increasing velocity gradients, which are largest near the vessel walls. For a typical volume depth of 6 mm (or 256 pixel), the analysis indicates that the velocity derived from 3D cross-correlation can be measured within ±2% of the maximum velocity (or ±0.2 pixel) near the center of the vessel and within ±5% (±0.6 pixel) near the vessel wall. The technique is then applied to acquire 3D-3C velocity field data at multiple axial locations within the carotid artery model, which are combined to yield the flow field and WSS in a volume of approximately 26 mm × 27 mm × 60 mm. Shear stress is computed from the velocity gradient tensor and a method for inferring the WSS distribution on the vessel wall is presented. The results indicate the presence of a complex and three-dimensional flow structure, with

  8. Temperature distribution in atherosclerotic coronary arteries: influence of plaque geometry and flow (a numerical study)

    Have, A G ten; Gijsen, F J H; Wentzel, J J; Slager, C J; Steen, A F W van der

    2004-01-01

    Intravascular coronary thermography is a method that may detect vulnerable, atherosclerotic plaques and is currently evaluated in a clinical setting. Active macrophages or enzymatic heat releasing processes in vulnerable plaques may act as heat sources. To better understand the parameters of influence on thermographic measurements, numerical simulations have been performed on a model of a coronary artery segment containing a heat source. Heat source parameters and flow were varied to study their influence on temperatures at the lumen wall. Maximal temperature differences at the lumen wall increased when the source volume increased and they differ with the source geometry. The simulations showed that blood flow acts as a coolant to the lumen wall. Blood flow decreased maximal temperatures depending on the source geometry, source volume and the maximal flow velocity. Influence of flow was highest for circumferentially extended sources, up to a factor 3.7, and lowest for longitudinally extended sources, down to a factor 1.9. When cap thickness increased, maximal temperatures decreased and the influence of flow increased. This study shows that correct interpretation of intravascular thermographic measurements requires data on the flow and on the morphologic characteristics of the atherosclerotic plaque

  9. Analysis of flow dynamics of main pulmonary artery by cine phase contrast MR angiography

    Honda, Norinari; Machida, Kikuo; Mamiya, Toshio

    1996-01-01

    Nineteen studies of cine phase contrast MR angiography (PCMRA) of main pulmonary artery (MPA) entered the study. Cine PCMRA was obtained by a 1.5T MR imager with a gradient echo sequence coupled with velocity encoding bipolar pulses. Retrospective EKG gating was used. Mean velocity, maximum velocity, and maximum flow rate of MPA were 6.2 to 28 cm/s (mean/SD 13/5.1, n=18), 61 to 148 cm/s (mean/SD 102/30, n=13), and 12,561 to 30,113 ml/min (mean/SD 18,730/5,464, n=18), respectively. Retrograde flow in the MPA was noted to begin at late-to mid-systole. Retrograde flow occurred first in the posterior part (15/19) or occurred from periphery (4/19). Thus hemodynamic parameters and velocity maps of MPA can be obtained by cine PCMRA. (author)

  10. Intravenous digital subtraction angiography for the evaluation of renal artery blood flow following the removal of a neuroblastoma

    Yamagiwa, Iwao; Obata, Kazuya; Saito, Hiroyuki; Washio, Masahiko

    1994-01-01

    There have been several reports of acute renal failure following the resection of an abdominal neuroblastoma combined with ipsilateral nephrectomy as well as the atrophy or disappearance of an unresected kidney after tumor resection. Spasms or thrombosis of the renal artery during tumor excision are considered to be the major cause. Since 1989, intravenous digital subtraction angiography (IVDSA) has been used to evaluate the renal artery blood flow immediately following surgery in seven patients with abdominal neuroblastomas. IVDSA was performed using a central venous catheter inserted prior to surgery. In all seven patients, IVDSA provided clear images for the evaluation of renal artery blood flow. In one of the two patients whose kidneys briefly became cyanosed during tumor excision, IVDSA demonstrated an occlusion of the renal artery and prompt measures could be taken to reestablish the blood flow. No complications of IVDSA occurred in any of the seven patients. IVDSA using a central venous catheter was thus considered to be useful for evaluating the renal artery blood flow in patients with a suspected renal artery blood flow disturbance without any risk of complications, and this modality obviated the need for intraarterial angiography. (author)

  11. Heat stress redistributes blood flow in arteries of the brain during dynamic exercise.

    Sato, Kohei; Oue, Anna; Yoneya, Marina; Sadamoto, Tomoko; Ogoh, Shigehiko

    2016-04-01

    We hypothesized that heat stress would decrease anterior and posterior cerebral blood flow (CBF) during exercise, and the reduction in anterior CBF would be partly associated with large increase in extracranial blood flow (BF). Nine subjects performed 40 min of semirecumbent cycling at 60% of the peak oxygen uptake in hot (35°C; Heat) and thermoneutral environments (25°C; Control). We evaluated BF and conductance (COND) in the external carotid artery (ECA), internal carotid artery (ICA), and vertebral artery (VA) using ultrasonography. During the Heat condition, ICA and VA BF were significantly increased 10 min after the start of exercise (P Heat. Compared with the Control, either BF or COND of ICA and VA at the end of Heat tended to be lower, but not significantly. In contrast, ECA BF and COND at the end of Heat were both higher than levels in the Control condition (P Heat, a reduction in ICA BF appears to be associated with a decline in end-tidal CO2 tension (r = 0.84), whereas VA BF appears to be affected by a change in cardiac output (r = 0.87). In addition, a change in ECA BF during Heat was negatively correlated with a change in ICA BF (r = -0.75). Heat stress resulted in modification of the vascular response of head and brain arteries to exercise, which resulted in an alteration in the distribution of cardiac output. Moreover, a hyperthermia-induced increase in extracranial BF might compromise anterior CBF during exercise with heat stress. Copyright © 2016 the American Physiological Society.

  12. Ocular Straylight

    Sigrid Mueller-Schotte OD, MSc

    2015-10-01

    Full Text Available Intra-ocular straylight can cause decreased visual functioning, and it may cause diminished vision-related quality of life (VRQOL. This cross-sectional population-based study investigates the association between straylight and VRQOL in middle-aged and elderly individuals. Multivariable linear regression analyses were used to assess the association between straylight modeled continuously and cutoff at the recommended fitness-to-drive value, straylight ≥ 1.4 log(s, and VRQOL. The study showed that participants with normal straylight values, straylight ≤ 1.4 log(s, rated their VRQOL slightly better than those with high straylight values (straylight ≥ 1.4 log(s. Furthermore, multivariable regression analysis revealed a borderline statistical significant association ( p = .06 between intra-ocular straylight and self-reported VRQOL in middle-aged and elderly individuals. The association between straylight and self-reported VRQOL was not influenced by the status of the intra-ocular lens (natural vs. artificial intra-ocular lens after cataract extraction or the number of (instrumental activities of daily living that were reported as difficult for the elderly individuals.

  13. Numerical Investigation of Oxygenated and Deoxygenated Blood Flow through a Tapered Stenosed Arteries in Magnetic Field.

    M Y Abdollahzadeh Jamalabadi

    Full Text Available Current paper is focused on transient modeling of blood flow through a tapered stenosed arteries surrounded a by solenoid under the presence of heat transfer. The oxygenated and deoxygenated blood are considered here by the Newtonian and Non-Newtonian fluid (power law and Carreau-Yasuda models. The governing equations of bio magnetic fluid flow for an incompressible, laminar, homogeneous, non-Newtonian are solved by finite volume method with SIMPLE algorithm for structured grid. Both magnetization and electric current source terms are well thought-out in momentum and energy equations. The effects of fluid viscosity model, Hartmann number, and magnetic number on wall shear stress, shearing stress at the stenosis throat and maximum temperature of the system are investigated and are optimized. The current study results are in agreement with some of the existing findings in the literature and are useful in thermal and mechanical design of spatially varying magnets to control the drug delivery and biomagnetic fluid flows through tapered arteries.

  14. Biorheological Model on Flow of Herschel-Bulkley Fluid through a Tapered Arterial Stenosis with Dilatation.

    Priyadharshini, S; Ponalagusamy, R

    2015-01-01

    An analysis of blood flow through a tapered artery with stenosis and dilatation has been carried out where the blood is treated as incompressible Herschel-Bulkley fluid. A comparison between numerical values and analytical values of pressure gradient at the midpoint of stenotic region shows that the analytical expression for pressure gradient works well for the values of yield stress till 2.4. The wall shear stress and flow resistance increase significantly with axial distance and the increase is more in the case of converging tapered artery. A comparison study of velocity profiles, wall shear stress, and flow resistance for Newtonian, power law, Bingham-plastic, and Herschel-Bulkley fluids shows that the variation is greater for Herschel-Bulkley fluid than the other fluids. The obtained velocity profiles have been compared with the experimental data and it is observed that blood behaves like a Herschel-Bulkley fluid rather than power law, Bingham, and Newtonian fluids. It is observed that, in the case of a tapered stenosed tube, the streamline pattern follows a convex pattern when we move from r/R = 0 to r/R = 1 and it follows a concave pattern when we move from r/R = 0 to r/R = -1. Further, it is of opposite behaviour in the case of a tapered dilatation tube which forms new information that is, for the first time, added to the literature.

  15. Biorheological Model on Flow of Herschel-Bulkley Fluid through a Tapered Arterial Stenosis with Dilatation

    S. Priyadharshini

    2015-01-01

    Full Text Available An analysis of blood flow through a tapered artery with stenosis and dilatation has been carried out where the blood is treated as incompressible Herschel-Bulkley fluid. A comparison between numerical values and analytical values of pressure gradient at the midpoint of stenotic region shows that the analytical expression for pressure gradient works well for the values of yield stress till 2.4. The wall shear stress and flow resistance increase significantly with axial distance and the increase is more in the case of converging tapered artery. A comparison study of velocity profiles, wall shear stress, and flow resistance for Newtonian, power law, Bingham-plastic, and Herschel-Bulkley fluids shows that the variation is greater for Herschel-Bulkley fluid than the other fluids. The obtained velocity profiles have been compared with the experimental data and it is observed that blood behaves like a Herschel-Bulkley fluid rather than power law, Bingham, and Newtonian fluids. It is observed that, in the case of a tapered stenosed tube, the streamline pattern follows a convex pattern when we move from r/R=0 to r/R=1 and it follows a concave pattern when we move from r/R=0 to r/R=-1. Further, it is of opposite behaviour in the case of a tapered dilatation tube which forms new information that is, for the first time, added to the literature.

  16. Evaluation of MR angiography and blood flow measurement in abdominal and peripheral arterial occlusive disease

    Tabuchi, Kenji [Dokkyo Univ. School of Medicine, Mibu, Tochigi (Japan)

    2000-03-01

    To assess the characteristics of blood flow measurement with MR Angiography (MRA) to evaluate the status of vascular stenoses, two or three dimensional time-of-flight MRA and velocity-encoded cine MR were performed in the 230 segments of 35 patients, with abdominal and peripheral arterial occlusive diseases. In 11 of these 35 patients digital subtraction angiography was additionally underwent, and the stenotic findings was compared with MRA. There were 17 segments in which the velocity could not be measured, because the blood flow exceeded the upper limit of peak-encoded velocity (VENC) which was set at 120 cm/sec. Therefore, it is necessary to set the upper limit of VENC at higher than 120 cm/sec. There were 11 stenotic findings in DSA and 20 stenotic findings in MRA. Pulsatility Index (PI=(max velocity-min. velocity)/average velocity) were used for evaluating the blood flow waveform, and there were significant difference between the 11 stenotic findings of DSA and the others'. In summery, MRA was considered as useful examination to assess the degree of the vascular stenoses in abdominal and peripheral arterial occlusive disease. (author)

  17. Divergence-free smoothing for MRV data on stenosed carotid artery phantom flows

    Im, Chaehyuk; Ko, Seungbin; Song, Simon

    2017-11-01

    Magnetic Resonance Velocimetry (MRV) is a versatile technique for measuring flow velocity using an MRI machine. It is frequently used for visualization and analysis of blood flows. However, it is difficult to accurately estimate hemodynamics parameters like wall shear stress (WSS) and oscillatory shear index (OSI) due to its low spatial resolution and low signal-to-noise ratio. We suggest a divergence-free smoothing (DFS) method to correct the erroneous velocity vectors obtained with MRV and improve the estimation accuracy of those parameters. Unlike previous studies on DFS for a wall-free flow, we developed a house code to apply a DFS method to a wall-bounded flow. A Hagen-Poiseuille flow and stenosed carotid artery phantom flows were measured with MRV. Each of them was analyzed for validation of the DFS code and confirmation on the accuracy improvement of hemodynamic parameters. We will discuss the effects of DFS on the improvement of the estimation accuracy of velocity vectors, WSS, OSI and etc in detail This work was supported by the National Research Foundation of Korea(NRF) Grant funded by the Korea government(MSIP) (No. 2016R1A2B3009541).

  18. Quantification of blood flow in the middle cerebral artery with phase-contrast MR imaging

    Stock, K.W.; Wetzel, S.G.; Radue, E.W. [Dept. of Radiology, Division of Neuroradiology, University Hospital of Basel (Switzerland); Lyrer, P.A. [Dept. of Neurology, University Hospital of Basel (Switzerland)

    2000-11-01

    The aim of this study was to assess blood flow in the middle cerebral artery (MCA) according to age, gender, and side. Eighty-eight subjects without carotid obstruction were measured for mean velocity, vessel area, and volume flow rates of both MCA with phase-contrast MR. A high-resolution sequence with a matrix of 300 x 512 and a double oblique localizing strategy was used for measurement. A mean velocity of 33 {+-} 6.8 cm/s, a mean vessel area of 6.2 {+-} 1.2 mm{sup 2} and a mean flow rate of 121 {+-} 28 ml/min were measured in the MCA. Lower volume flow rates were seen in subjects aged over 50 years (p < 0.01). When comparing women with men, a lower vessel area (p < 0.05) of the MCA was counterbalanced by a higher velocity, resulting in no significant difference of the volume flow rate. No difference occurred between the right and the left side. Flow reduction occurs in the elderly. A lower vessel area of the MCA in women is compensated by a higher velocity. (orig.)

  19. Prediction of blood pressure and blood flow in stenosed renal arteries using CFD

    Jhunjhunwala, Pooja; Padole, P. M.; Thombre, S. B.; Sane, Atul

    2018-04-01

    In the present work an attempt is made to develop a diagnostive tool for renal artery stenosis (RAS) which is inexpensive and in-vitro. To analyse the effects of increase in the degree of severity of stenosis on hypertension and blood flow, haemodynamic parameters are studied by performing numerical simulations. A total of 16 stenosed models with varying degree of stenosis severity from 0-97.11% are assessed numerically. Blood is modelled as a shear-thinning, non-Newtonian fluid using the Carreau model. Computational Fluid Dynamics (CFD) analysis is carried out to compute the values of flow parameters like maximum velocity and maximum pressure attained by blood due to stenosis under pulsatile flow. These values are further used to compute the increase in blood pressure and decrease in available blood flow to kidney. The computed available blood flow and secondary hypertension for varying extent of stenosis are mapped by curve fitting technique using MATLAB and a mathematical model is developed. Based on these mathematical models, a quantification tool is developed for tentative prediction of probable availability of blood flow to the kidney and severity of stenosis if secondary hypertension is known.

  20. Quantification of blood flow in the middle cerebral artery with phase-contrast MR imaging

    Stock, K.W.; Wetzel, S.G.; Radue, E.W.; Lyrer, P.A.

    2000-01-01

    The aim of this study was to assess blood flow in the middle cerebral artery (MCA) according to age, gender, and side. Eighty-eight subjects without carotid obstruction were measured for mean velocity, vessel area, and volume flow rates of both MCA with phase-contrast MR. A high-resolution sequence with a matrix of 300 x 512 and a double oblique localizing strategy was used for measurement. A mean velocity of 33 ± 6.8 cm/s, a mean vessel area of 6.2 ± 1.2 mm 2 and a mean flow rate of 121 ± 28 ml/min were measured in the MCA. Lower volume flow rates were seen in subjects aged over 50 years (p < 0.01). When comparing women with men, a lower vessel area (p < 0.05) of the MCA was counterbalanced by a higher velocity, resulting in no significant difference of the volume flow rate. No difference occurred between the right and the left side. Flow reduction occurs in the elderly. A lower vessel area of the MCA in women is compensated by a higher velocity. (orig.)

  1. Experimental investigation of the flow of a blood analogue fluid in a replica of a bifurcated small artery.

    Anastasiou, A D; Spyrogianni, A S; Koskinas, K C; Giannoglou, G D; Paras, S V

    2012-03-01

    The scope of this work is to study the pulsatile flow of a blood mimicking fluid in a micro channel that simulates a bifurcated small artery, in which the Fahraeus-Lindqvist effect is insignificant. An aqueous glycerol solution with small amounts of xanthan gum was used for simulating viscoelastic properties of blood and in vivo flow conditions were reproduced. Local flow velocities were measured using micro Particle Image Velocimetry (μ-PIV). From the measured velocity distributions, the wall shear stress (WSS) and its variation during a pulse were estimated. The Reynolds numbers employed are relatively low, i.e. similar to those prevailing during blood flow in small arteries. Experiments both with a Newtonian and a non-Newtonian fluid (having asymptotic viscosity equal to the viscosity of the Newtonian one) proved that the common assumption that blood behaves as a Newtonian fluid is not valid for blood flow in small arteries. It was also shown that the outer wall of the bifurcation, which is exposed to a lower WSS, is more predisposed to atherosclerotic plaque formation. Moreover, this region in small vessels is shorter than the one in large arteries, as the developed secondary flow decays faster. Finally, the WSS values in small arteries were found to be lower than those in large ones. Copyright © 2011 IPEM. Published by Elsevier Ltd. All rights reserved.

  2. Renal blood flow after selective injection of different dosages of diatrizoate into the renal artery

    Burgener, F.A.; Fischer, H.W.; Weber, D.A.

    1975-01-01

    The characteristic biphasic renal haemodynamic response to diatrizoate injected into the renal artery was shown in the dog with the 133-xenon washout technique. A brief increase in renal blood flow (RBF) during the first ten seconds is followed by a more prolonged period of diminuished RBF. A dose of 4 ml. diatrizoate 60% resulted in the maximum RBF increase of 43% after ten seconds, but even 1 ml. diatrizoate raised the RBF 24%. The initial vasodilator effect of diatrizoate compares well in its extent with the most potent renal vasodilators. (orig.) [de

  3. Scaling of Myocardial Mass to Flow and Morphometry of Coronary Arteries

    Choy, Jenny Susana; Kassab, Ghassan S.

    2008-01-01

    There is no doubt that scaling relations exist between myocardial mass and morphometry of coronary vasculature. The purpose of this study is to quantify several morphological (diameter, length, and volume) and functional (flow) parameters of the coronary arterial tree in relation to myocardial mass. Eight normal porcine hearts of 117-244 g (mean of 177.5±32.7) were used in this study. Various coronary sub-trees of the Left Anterior Descending (LAD), Right Coronary (RCA) and Left Circumflex (L...

  4. Blood flow of Jeffrey fluid in a catherized tapered artery with the suspension of nanoparticles

    Ellahi, R., E-mail: rellahi@engr.ucr.edu [Department of Mechanical Engineering, University of California Riverside (United States); Department of Mathematics and Statistics, FBAS, IIU, Islamabad (Pakistan); Rahman, S.U. [Department of Mathematics and Statistics, FBAS, IIU, Islamabad (Pakistan); Nadeem, S. [Department of Mathematics, Quaid-i-Azam University Islamabad (Pakistan)

    2014-08-14

    Current letter deals with the mathematical models of Jeffrey fluid via nanoparticles in the tapered stenosed atherosclerotic arteries. The convection effects of heat transfer with catheter are also taken into account. The nonlinear coupled equations of nanofluid model are simplified under mild stenosis. The solutions for concentration and temperature are found by using homotopy perturbation method, whereas for velocity profile the exact solution is calculated. Moreover, the expressions for flow impedance and pressure rise are computed and discussed through graphs for different physical quantities of interest. The streamlines have also been presented to discuss the trapping bolus discipline.

  5. Renal blood flow, diuresis and isotope nephrogram in experimental stenosis of the renal artery

    Pemsel, H.K.; Lange, H.; Mahlstedt, J.; Joseph, K.; Marburg Univ.; Marburg Univ.

    1979-01-01

    After experimental stenosis of the renal artery of the dog, the isotope nephrogram shows a prolongation of the transit-time, when the renal blood flow is reduced to 40-70%. This finding was most significant in low diuresis (0,05-0,2 ml/min), sporadic in moderate diuresis (0,2-2,0 ml/min), no longer demonstrable in forced diuresis (>2,0 ml/min). The diuretic effect of X-ray contrast-medium (70% Na-Meglumin-Jotalamat, 0,5 ml/kg i.v.) normalizes a pathologic ING in low diuresis. (orig.) [de

  6. Myocardial flow reserve is influenced by both coronary artery stenosis severity and coronary risk factors in patients with suspected coronary artery disease

    Tsukamoto, Takahiro; Naya, Masanao; Tsutsui, Hiroyuki; Morita, Koichi; Katoh, Chietsugu; Inubushi, Masayuki; Kuge, Yuji; Tamaki, Nagara

    2006-01-01

    Myocardial flow reserve (MFR) measurement has an important role in assessing the functional severity of coronary artery stenosis. However, a discrepancy between the anatomical severity of coronary artery stenosis and MFR is often observed. Such a discrepancy may be explained by coronary risk factors. In this study, we aimed to investigate the influence of coronary artery stenosis severity and risk factors on MFR. Seventy-four patients suspected to have coronary artery disease and seven age-matched healthy volunteers were enrolled. Myocardial blood flow (MBF) and MFR were measured using 15 O-labelled water PET. Regional MFR was calculated in regions with significant coronary artery stenosis (stenotic regions) and in regions without significant stenosis (remote regions). The contributions of coronary artery stenosis severity and coronary risk factors were assessed using univariate and multivariate analyses. In stenotic regions, MFR correlated inversely with coronary artery stenosis severity (r=-0.50, p<0.01). Univariate analysis did not show any significant difference in MFR between the patients with and the patients without each risk factor. In remote regions, however, MFR was significantly decreased in the diabetes and smoking groups (each p<0.05). By multivariate analysis, diabetes and smoking were independent predictors of MFR (each p<0.05). In the group with more than one risk factor, MFR was significantly lower (2.78±0.79) than in the other group (3.40±1.22, p<0.05). MFR is influenced not only by coronary stenosis severity but also by coronary risk factors. In particular, the influence of risk factors should be considered in regions without severe coronary stenosis. (orig.)

  7. Sports-related flow limitations in the iliac arteries in endurance athletes : aetiology, diagnosis, treatment and future developments

    Bender, M.H.M.; Schep, G.; Vries, de W.R.; Hoogeveen, A.R.; Wijn, P.F.F.

    2004-01-01

    Approximately one in five top-level cyclists will develop sports-related flow limitations in the iliac arteries. These flow limitations may be caused by a vascular lumen narrowing due to endofibrotic thickening of the intima and/or by kinking of the vessels. In some athletes, extreme vessel length

  8. Fluid-structure interaction modeling of aneurysmal arteries under steady-state and pulsatile blood flow: a stability analysis.

    Sharzehee, Mohammadali; Khalafvand, Seyed Saeid; Han, Hai-Chao

    2018-02-01

    Tortuous aneurysmal arteries are often associated with a higher risk of rupture but the mechanism remains unclear. The goal of this study was to analyze the buckling and post-buckling behaviors of aneurysmal arteries under pulsatile flow. To accomplish this goal, we analyzed the buckling behavior of model carotid and abdominal aorta with aneurysms by utilizing fluid-structure interaction (FSI) method with realistic waveforms boundary conditions. FSI simulations were done under steady-state and pulsatile flow for normal (1.5) and reduced (1.3) axial stretch ratios to investigate the influence of aneurysm, pulsatile lumen pressure and axial tension on stability. Our results indicated that aneurysmal artery buckled at the critical buckling pressure and its deflection nonlinearly increased with increasing lumen pressure. Buckling elevates the peak stress (up to 118%). The maximum aneurysm wall stress at pulsatile FSI flow was (29%) higher than under static pressure at the peak lumen pressure of 130 mmHg. Buckling results show an increase in lumen shear stress at the inner side of the maximum deflection. Vortex flow was dramatically enlarged with increasing lumen pressure and artery diameter. Aneurysmal arteries are more susceptible than normal arteries to mechanical instability which causes high stresses in the aneurysm wall that could lead to aneurysm rupture.

  9. 3-D flow characterization and shear stress in a stenosed carotid artery bifurcation model using stereoscopic PIV technique.

    Kefayati, Sarah; Poepping, Tamie L

    2010-01-01

    The carotid artery bifurcation is a common site of atherosclerosis which is a major leading cause of ischemic stroke. The impact of stenosis in the atherosclerotic carotid artery is to disturb the flow pattern and produce regions with high shear rate, turbulence, and recirculation, which are key hemodynamic factors associated with plaque rupture, clot formation, and embolism. In order to characterize the disturbed flow in the stenosed carotid artery, stereoscopic PIV measurements were performed in a transparent model with 50% stenosis under pulsatile flow conditions. Simulated ECG gating of the flowrate waveform provides external triggering required for volumetric reconstruction of the complex flow patterns. Based on the three-component velocity data in the lumen region, volumetric shear-stress patterns were derived.

  10. Pulmonary branch arterial flow can be measured with cine MR velocity mapping

    Caputo, G.R.; Kondo, C.; Masui, T.; Foster, E.; Geraci, S.J.; O'Sullivan, M.; Higgins, C.B.

    1990-01-01

    This paper assesses the capability of cine MR phase velocity mapping (CVM) to measure main, right-sided, and left-sided pulmonary arterial (PA) blood flow. The authors examined a constant-flow phantom and nine healthy volunteers with use of 1.5-T MR imaging system (GE Signa) with phase velocity cine sequences. CVM correctly measured constant-flow phantom velocities (range, 20-190 cm/sec; r = .998, SEE = 4.2 cm/sec), and velocity with use of angulated planes to section the phantom tube perpendicularly. CVM peak systolic main PA velocity (79 cm/sec ± 10) correlated well with Doppler US measurements (80 cm/sec ± 7). CVM main PA flow correlated well with conventional cine MR LV stroke volume measurements (r = .98, SEE = 4.8 mL). Left and right PA flow on the angulated planes were 29 mL ± 7 and 34 mL ± 10, respectively

  11. En bloc resection of skull base tumor including internal carotid artery. Preoperative evaluation of cerebral blood flow

    Okamoto, Yoshitaka; Matsuzaki, Zensei; Kamijo, Atsushi; Ogino, Jun; Nagaseki, Yoshishige; Nukui, Hideaki; Yokomizo, Michinori; Togawa, Kiyoshi

    1998-01-01

    Carotid artery resection yields a possibility of cure in patients with advanced head and neck carcinoma involving the carotid artery. However, the criteria for the identification of those who are vulnerable to neurologic injury after resection have not been established. Interposition graft covered with a well-vascularized flap could minimize the rate of perioperative morbidity. Particularly, when an extensive resection of the skull base including carotid artery and sigmoid vein, is planned, extracranial-intracranial bypass should be considered to minimize the risks of neurologic morbidity, even if preresection positron emission tomography during balloon test occlusion of internal carotid artery suggested the adequacy of hemispheric collateral blood flow. In these cases, the temporary occlusion of the carotid artery is not an accurate prediction of the morbidity after permanent occlusion. (author)

  12. On the relationship between competitive flow and FFT analysis of the flow waves in the left internal mammary artery graft in the process of CABG.

    Mao, Boyan; Wang, Wenxin; Zhao, Zhou; Zhao, Xi; Li, Lanlan; Zhang, Huixia; Liu, Youjun

    2016-12-28

    During coronary artery bypass grafting (CABG), the ratio of powers of the fundamental frequency and its first harmonic (F0/H1) in fast Fourier transformation (FFT) analysis of the graft's flow waves has been used in the field of evaluation of the patency in anastomosis. But there is no report about using the FFT method to evaluate the magnitude of competitive flow. This study is aiming at exploring the relationship between competitive flow and FFT analysis of the flow waves in left internal mammary artery (LIMA) graft, and finding a new method to evaluate the magnitude of competitive flow. At first, establishing the CABG multiscale models of different stenosis in left anterior descending artery (LAD) to get different magnitude of competitive flows. Then, calculating the models by ANSYS-CFX and getting the flow waves in LIMA. Finally, analyzing the flow waves by FFT method and comparing the FFT results with the magnitude of competitive flow. There is no relationship between competitive flow and F0/H1. As for F0/H2 and F0/H3, they both increase with the reduction of the stenosis in LAD. But the increase of F0/H3 is not obviously enough and it can't identify the significant competitive flow clearly, so it can't be used as the evaluation index. It is found that F0/H2 increases obviously with the increase of the competitive flow and can identify the significant competitive flow. The FFT method can be used in the evaluation of competitive flow and the F0/H2 is the ideal index. High F0/H2 refers to the significant competitive flow. This method can be used during CABG to avoid the risk of competitive flow.

  13. Impaired increase of retinal capillary blood flow to flicker light exposure in arterial hypertension.

    Ritt, Martin; Harazny, Joanna M; Ott, Christian; Raff, Ulrike; Bauernschubert, Philipp; Lehmann, Marina; Michelson, Georg; Schmieder, Roland E

    2012-09-01

    We hypothesized that the increase of retinal capillary blood flow (RCF) to flicker light exposure is impaired in subjects with arterial hypertension. In 146 nondiabetic untreated male subjects with (n=50) or without (n=96) arterial hypertension, RCF was measured before and after flicker light exposure noninvasively and in vivo using scanning laser Doppler flowmetry. In addition, in a subgroup of 28 subjects, the change of RCF to flicker light exposure was again assessed during parallel infusion of nitric oxide synthase inhibitor N-monomethyl-L-arginine (L-NMMA). The increase of RCF to flicker light exposure was lower in patients with untreated hypertension compared with normotensive subjects when expressed in absolute terms (7.69±54 versus 27.2±44 AU; P adjusted=0.013) or percent changes (2.95±14 versus 8.33±12%; P adjusted=0.023). Systolic (β=-0.216; P=0.023) but not diastolic blood pressure (β=-0.117; P=0.243) or mean arterial pressure (β=-0.178; P=0.073) was negatively related to the percent change of RCF to flicker light exposure, independently of other cardiovascular risk factors. In the subgroup of 28 subjects, the increase of RCF to flicker light exposure was similar at baseline and during parallel infusion of L-NMMA when expressed in absolute terms (20.0±51 versus 22.6±56 AU; P=0.731) or percent changes (7.12±16 versus 8.29±18%; P=0.607). The increase of RCF to flicker light exposure is impaired in arterial hypertension. In the subgroup of the total study cohort, nitric oxide was not a major determinant of the increase of RCF to flicker light exposure.

  14. Noninvasive arterial blood pressure waveforms in patients with continuous-flow left ventricular assist devices.

    Martina, Jerson R; Westerhof, Berend E; de Jonge, Nicolaas; van Goudoever, Jeroen; Westers, Paul; Chamuleau, Steven; van Dijk, Diederik; Rodermans, Ben F M; de Mol, Bas A J M; Lahpor, Jaap R

    2014-01-01

    Arterial blood pressure and echocardiography may provide useful physiological information regarding cardiac support in patients with continuous-flow left ventricular assist devices (cf-LVADs). We investigated the accuracy and characteristics of noninvasive blood pressure during cf-LVAD support. Noninvasive arterial pressure waveforms were recorded with Nexfin (BMEYE, Amsterdam, The Netherlands). First, these measurements were validated simultaneously with invasive arterial pressures in 29 intensive care unit patients. Next, the association between blood pressure responses and measures derived by echocardiography, including left ventricular end-diastolic dimensions (LVEDDs), left ventricular end-systolic dimensions (LVESDs), and left ventricular shortening fraction (LVSF) were determined during pump speed change procedures in 30 outpatients. Noninvasive arterial blood pressure waveforms by the Nexfin monitor slightly underestimated invasive measures during cf-LVAD support. Differences between noninvasive and invasive measures (mean ± SD) of systolic, diastolic, mean, and pulse pressures were -7.6 ± 5.8, -7.0 ± 5.2, -6.9 ± 5.1, and -0.6 ± 4.5 mm Hg, respectively (all blood pressure responses did not correlate with LVEDD, LVESD, or LVSF, while LVSF correlated weakly with both pulse pressure (r = 0.24; p = 0.005) and (dP(art)/dt)max (r = 0.25; p = 0.004). The dicrotic notch in the pressure waveform was a better predictor of aortic valve opening (area under the curve [AUC] = 0.87) than pulse pressure (AUC = 0.64) and (dP(art)/dt)max (AUC = 0.61). Patients with partial support rather than full support at 9,000 rpm had a significant change in systolic pressure, pulse pressure, and (dP(art)/dt)max during ramp studies, while echocardiographic measures did not change. Blood pressure measurements by Nexfin were reliable and may thereby act as a compliment to the assessment of the cf-LVAD patient.

  15. Color doppler flow imaging in evaluation of uterine arterial embolization of leiomyoma with KMG

    Li Furong; Guo Yunhuai; Liu Lifang; Liu Jianhua; Guo Yunhuai

    2006-01-01

    Objective: To explore the effectiveness of a new kind of embolization agent-sodium alginate(KMG), and to evaluate the clinical value of 2D color Doppler ultrasound in assessing the therapeutic effect of uterine arterial embolization (UAE) in leiomyomas. Methods: Forty nine patients with symptomatic leiomyomas were undertaken UAE with KMG for the treatment. Sonography was performed at 3-7 days before and, 1, 3, 6 months after UAE with 2D color Doppler for evaluating the 2D echograms and hemodynamics. Results: Forty nine leiomyomas were studied after UAE, showing a marked reduction in the size (35%-90%). No blood flow was demonstrated in the leiomyomas either 3-7 days or 1 month or 3 months after the procedure. The reappearance of blood flow could be seen in only one case. Conclusion: KMG is an efficient embolization agent for the treatment of symptomatic leiomyomas with UAE, and ultrasonography is a useful tool to assess the effectiveness. (authors)

  16. A SPECT study in internal carotid artery occlusion: Discrepancies between flow image and neurologic deficits

    Moriwaki, H.; Hougaku, H.; Matsuda, I.; Kusunoki, M.; Shirai, J.

    1989-01-01

    A SPECT (single photon emission computed tomography) study in internal carotid artery (ICA) occlusion was performed in 6 patients. The validity of iodoamphetamine (IMP) SPECT study in the evaluation of cerebral blood flow (CBF) or neurologic function is still controversial. In this study, the authors showed several cases in whom SPECT images of brain were not compatible with their neurologic deficits. In 2 typical cases, a large low-density area was observed in the non-dominant hemisphere in computed tomography (CT) scan, but no apparent motor-sensory deficits in left limbs were present. In these patients, SPECT study also revealed flow reduction in the affected side of the brain. So there was a possibility that an IMP brain image could not always reflect CBF, which maintains neurologic function of the brain

  17. A theoretical description of arterial pressure-flow relationships with verification in the isolated hindlimb of the dog.

    Jackman, A P; Green, J F

    1990-01-01

    We developed and tested a new two-compartment serial model of the arterial vasculature which unifies the capacitance (downstream arterial compliance) and waterfall (constant downstream pressure load) theories of blood flow through the arteries. In this model, blood drains from an upstream compliance through a resistance into a downstream compliance which empties into the veins through a downstream resistance which terminates in a constant pressure load. Using transient arterial pressure data obtained from an isolated canine hindlimb preparation, we tested this model, using a stop-flow technique. Numerical parameter estimation techniques were used to estimate the physiologic parameters of the model. The downstream compliance was found to be more than ten times larger than the upstream compliance and the constant pressure load was significantly above venous pressures but decreased in response to vasodilation. Our results support the applicability of both the capacitance and waterfall theories.

  18. Arterial spin labeling blood flow magnetic resonance imaging for evaluation of renal injury.

    Liu, Yupin P; Song, Rui; Liang, Chang hong; Chen, Xin; Liu, Bo

    2012-08-15

    A multitude of evidence suggests that iodinated contrast material causes nephrotoxicity; however, there have been no previous studies that use arterial spin labeling (ASL) blood flow functional magnetic resonance imaging (fMRI) to investigate the alterations in effective renal plasma flow between normointensive and hypertensive rats following injection of contrast media. We hypothesized that FAIR-SSFSE arterial spin labeling MRI may enable noninvasive and quantitative assessment of regional renal blood flow abnormalities and correlate with disease severity as assessed by histological methods. Renal blood flow (RBF) values of the cortex and medulla of rat kidneys were obtained from ASL images postprocessed at ADW4.3 workstation 0.3, 24, 48, and 72 h before and after injection of iodinated contrast media (6 ml/kg). The H&E method for morphometric measurements was used to confirm the MRI findings. The RBF values of the outer medulla were lower than those of the cortex and the inner medulla as reported previously. Iodinated contrast media treatment resulted in decreases in RBF in the outer medulla and cortex in spontaneously hypertensive rats (SHR), but only in the outer medulla in normotensive rats. The iodinated contrast agent significantly decreased the RBF value in the outer medulla and the cortex in SHR compared with normotensive rats after injection of the iodinated contrast media. Histological observations of kidney morphology were also consistent with ASL perfusion changes. These results demonstrate that the RBF value can reflect changes of renal perfusion in the cortex and medulla. ASL-MRI is a feasible and accurate method for evaluating nephrotoxic drugs-induced kidney damage.

  19. Continuous determination of regional myocardial blood flow with intracoronary krypton-81m in coronary artery disease

    Remme, W.J.; Krauss, X.H.; van Hoogenhuyze, D.C.; Cox, P.H.; Storm, C.J.; Kruyssen, D.A.

    1985-01-01

    Pacing-induced changes in regional coronary flow were studied continuously with krypton-81m by intracoronary infusion in 25 patients: 21 with 50% or greater diameter narrowing of 1 or more left coronary arteries (group I) and 4 with less than 50% diameter reduction of a left coronary artery (group II). No changes occurred in group II. In group I, krypton-81m perfusion decreased progressively in all areas with more than 70% diameter narrowing, with a simultaneous increase in normal regions. At the end of pacing during angina, krypton-81m perfusion was reduced to 81 +/- 4% of control in areas with 71 to 90% diameter reduction (n = 8) and to 69 +/- 6% in areas with more than 90% diameter narrowing (n = 15). In contrast, in regions with 50 to 70% diameter reduction changes were variable (decrease in 4 regions, increase in 2 and an unchanged distribution in 1 region). Krypton-81m perfusion decreased early, before general signs of ischemia in areas with more than 90% diameter reduction, whereas this decrease occurred later in regions with 71 to 90% diameter narrowing, concurrently with ST-segment changes but before anginal pain. Although all signs of ischemia had disappeared between 2 and 5 minutes after pacing, changes in krypton-81m distribution persisted in most areas for 5 to 15 minutes after pacing. It is concluded that the functional significance of coronary arterial narrowing can be assessed with a continuous intracoronary infusion of krypton-81m. Changes in regional distribution persisted after cessation of pacing-induced ischemia, indicating an ongoing decrease in regional myocardial blood flow

  20. Noninvasive estimation of pulmonary arterial pressure by analysis of pulmonary blood-flow distribution

    Konstam, M.A.; Strauss, H.W.; Alpert, N.M.; Miller, S.W.; Murphy, R.X.; Greene, R.E.; McKusick, K.A.

    1979-01-01

    To determine whether a correlation exists between pulmonary arterial (PA) pressure (P/sub a/) and the distribution of pulmonary blood flow, this distribution was measured in four upright dogs in the control state and during intravenous infusions of epinephrine or prostaglandin F/sub 2α/. During suspension of respiration, 15 mCi of Xe-133 were injected intravenously, and perfusion and equilibration lung images were recorded with a scintillation camera. The procedure was performed several times on each dog, with and without pharmacological elevation of PA pressure by 5 to 50 cm H 2 O. For each scintigram, the relative blood flow per unit ventilated lung volume (F) was plotted against centimeters above the hilum (h). Pulmonary arterial pressure was derived from each curve, assuming the relation F = B(P/sub a/ - hD) 2 , where B = constant and D = specific gravity of blood. Calculated PA pressure correlated strongly (r = 0.83) with measured PA pressure, suggesting a possible means of noninvasive estimation of PA pressure

  1. Changes in Hepatic Blood Flow During Transcatheter Arterial Infusion with Heated Saline in Hepatic VX2 Tumor

    Cao Wei; Li Jing; Wu Zhiqun; Zhou Changxi; Liu Xi; Wan Yi; Duan Yunyou

    2013-01-01

    Purpose. This study evaluates the influence of transcatheter arterial infusion with heated saline on hepatic arterial and portal venous blood flows to tumor and normal hepatic tissues in a rabbit VX2 tumor model. Methods. All animal experiments were approved by the institutional animal care and use committee. Twenty rabbits with VX2 liver tumors were divided into the following two groups: (a) the treated group (n = 10), which received a 60 mL transarterial injection of 60 °C saline via the hepatic artery; (b) the control group (n = 10), which received a 60 mL injection of 37 °C saline via the hepatic artery. Using ultrasonography, the blood flows in both the portal vein and hepatic artery were measured, and the changes in the hemodynamic indices were recorded before and immediately after the injection. The changes in the tumor and normal liver tissues of the two groups were histopathologically examined by hematoxylin and eosin staining after the injection. Results. After the transcatheter arterial heated infusion, there was a decrease in the hepatic arterial blood flow to the tumor tissue, a significant decrease in the hepatic artery mean velocity (P < 0.05), and a significant increase in the resistance index (P < 0.05). On hematoxylin and eosin staining, there were no obvious signs of tissue destruction in the normal liver tissue or the tumor tissue after heated perfusion, and coagulated blood plasma was observed in the cavities of intratumoral blood vessels in the treated group. Conclusions. The changes in tumor blood flow in the rabbit VX2 tumor model were presumably caused by microthrombi in the tumor vessels, and the portal vein likely mediated the heat loss in normal liver tissue during the transarterial heated infusion.

  2. Changes in Hepatic Blood Flow During Transcatheter Arterial Infusion with Heated Saline in Hepatic VX2 Tumor

    Cao Wei, E-mail: cawe-001@163.com [Tangdu Hospital, The Fourth Military Medical University, Department of Interventional Radiology (China); Li Jing, E-mail: lijing02@fmmu.edu.cn [Tangdu Hospital, The Fourth Military Medical University, Department of Burn and Plastic Surgery (China); Wu Zhiqun, E-mail: zhiqunwu@fmmu.edu.cn [Tangdu Hospital, The Fourth Military Medical University, Department of Interventional Radiology (China); Zhou Changxi, E-mail: changxizhou@163.com [Chinese PLA General Hospital, Department of Respiratory Disease (China); Liu Xi, E-mail: xiliu@fmmu.edu.cn [Tangdu Hospital, The Fourth Military Medical University, Department of Ultrasound Diagnostics (China); Wan Yi, E-mail: yiwan@163.com [The Fourth Military Medical University, Department of Health Statistics, Institute for Health Informatics (China); Duan Yunyou, E-mail: yunyouduan@fmmu.edu.cn [Tangdu Hospital, The Fourth Military Medical University, Department of Ultrasound Diagnostics (China)

    2013-06-15

    Purpose. This study evaluates the influence of transcatheter arterial infusion with heated saline on hepatic arterial and portal venous blood flows to tumor and normal hepatic tissues in a rabbit VX2 tumor model. Methods. All animal experiments were approved by the institutional animal care and use committee. Twenty rabbits with VX2 liver tumors were divided into the following two groups: (a) the treated group (n = 10), which received a 60 mL transarterial injection of 60 Degree-Sign C saline via the hepatic artery; (b) the control group (n = 10), which received a 60 mL injection of 37 Degree-Sign C saline via the hepatic artery. Using ultrasonography, the blood flows in both the portal vein and hepatic artery were measured, and the changes in the hemodynamic indices were recorded before and immediately after the injection. The changes in the tumor and normal liver tissues of the two groups were histopathologically examined by hematoxylin and eosin staining after the injection. Results. After the transcatheter arterial heated infusion, there was a decrease in the hepatic arterial blood flow to the tumor tissue, a significant decrease in the hepatic artery mean velocity (P < 0.05), and a significant increase in the resistance index (P < 0.05). On hematoxylin and eosin staining, there were no obvious signs of tissue destruction in the normal liver tissue or the tumor tissue after heated perfusion, and coagulated blood plasma was observed in the cavities of intratumoral blood vessels in the treated group. Conclusions. The changes in tumor blood flow in the rabbit VX2 tumor model were presumably caused by microthrombi in the tumor vessels, and the portal vein likely mediated the heat loss in normal liver tissue during the transarterial heated infusion.

  3. Balloon test occlusion of the internal carotid artery with stable xenon/CT cerebral blood flow imaging

    Erba, S.M.; Horton, J.A.; Latchaw, R.E.; Yonas, H.; Sekhar, L.; Schramm, V.; Pentheny, S.

    1988-01-01

    We describe a technique to predict preoperatively the safety of permanently occluding an internal carotid artery. The method was performed by imaging stable xenon cerebral blood flow (CBF) with the internal carotid artery both open and temporarily occluded with a nondetachable balloon on a double lumen Swan-Ganz catheter. Patients were those in whom we planned to sacrifice the internal carotid artery (those with giant or inaccessible aneurysms) or those in whom such a sacrifice was at least likely (those with skull base tumors). Patients were divided into three groups on the basis of a comparison of occluded and nonoccluded CBF values. Group-I patients had no significant change in CBF with internal carotid artery occlusion; group-II patients showed a symmetric decrease in CBF; and group-III patients had an asymmetric decrease in CBF, always greater on the occluded side. A fourth group clinically failed to tolerate even brief carotid occlusion. The internal carotid artery in one patients from group III was sacrificed at surgery: the size and shape of his postoperative infarct corresponded almost exactly to the area of asymmetrically decreased CBF on his occluded study. The data suggest that if surgery is likely to result in permanent occlusion of the internal carotid artery, then patients who are at risk for delayed neurologic injury due to a compromised cerebral blood flow should have arterial bypass grafts before such surgery is performed

  4. Aortopulmonary collateral flow is related to pulmonary artery size and affects ventricular dimensions in patients after the fontan procedure.

    Heiner Latus

    Full Text Available BACKGROUND: Aortopulmonary collaterals (APCs are frequently found in patients with a single-ventricle (SV circulation. However, knowledge about the clinical significance of the systemic-to-pulmonary shunt flow in patients after the modified Fontan procedure and its potential causes is limited. Accordingly, the aim of our study was to detect and quantify APC flow using cardiovascular magnetic resonance (CMR and assess its impact on SV volume and function as well as to evaluate the role of the size of the pulmonary arteries in regard to the development of APCs. METHODS: 60 patients (mean age 13.3 ± 6.8 years after the Fontan procedure without patent tunnel fenestration underwent CMR as part of their routine clinical assessment that included ventricular functional analysis and flow measurements in the inferior vena cava (IVC, superior vena cava (SVC and ascending aorta (Ao. APC flow was quantified using the systemic flow estimator: (Ao - (IVC + SVC. Pulmonary artery index (Nakata index was calculated as RPA + LPA area/body surface area using contrast enhanced MR angiography. The patient cohort was divided into two groups according to the median APC flow: group 1 0.495 l/min/m(2. RESULTS: Group 1 patients had significant smaller SV enddiastolic (71 ± 16 vs 87 ± 25 ml/m(2; p=0.004 and endsystolic volumes (29 ± 11 vs 40 ± 21 ml/m(2; p=0.02 whereas ejection fraction (59 ± 9 vs 56 ± 13%; p=0.38 differed not significantly. Interestingly, pulmonary artery size showed a significant inverse correlation with APC flow (r=-0.50, p=0.002. CONCLUSIONS: Volume load due to APC flow in Fontan patients affected SV dimensions, but did not result in an impairment of SV function. APC flow was related to small pulmonary artery size, suggesting that small pulmonary arteries represent a potential stimulus for the development of APCs.

  5. Value of MR phase-contrast flow measurements for functional assessment of pulmonary arterial hypertension

    Ley, Sebastian; Mereles, Derliz; Gruenig, Ekkehard; Puderbach, Michael; Schoeck, Helena; Eichinger, Monika; Ley-Zaporozhan, Julia; Fink, Christian; Kauczor, Hans-Ulrich

    2007-01-01

    Goals of our study were to compare the pulmonary hemodynamics between healthy volunteers and patients with pulmonary arterial hypertension (PAH) and correlate MR flow measurements with echocardiography. Twenty-five patients with PAH and 25 volunteers were examined at 1.5 T. Phase-contrast flow measurements were performed in the ascending aorta and pulmonary trunk, resulting in the following parameters: peak velocity (cm/s), average blood flow (l/min), time to peak velocity (ms), velocity rise gradient and pulmonary distensibility (cm 2 ). The bronchosystemic shunt was calculated. In PAH patients transthoracic echocardiography and right-heart catheterization (RHC) served as the gold standard. In comparison to volunteers, the PAH patients showed significantly reduced pulmonary velocities (P = 0.002), blood flow (P = 0.002) and pulmonary distensibility (P = 0.008). In patients, the time to peak velocity was shorter (P<0.001), and the velocity rise gradient was steeper (P = 0.002) than in volunteers. While in volunteers the peak velocity in the aorta was reached earlier, it was the reverse in patients. Patients showed a significant bronchosystemic shunt (P = 0.01). No meaningful correlation was found between MRI measurements and echocardiography or RHC. MRI is a feasible technique for the differentiation between PAH and volunteers. Further studies have to be conducted for the absolute calculation of pressure estimates. (orig.)

  6. Changes in myocardial blood flow and S-T segment elevation following coronary artery occlusion in dogs

    Smith, H.J.; Singh, B.N.; Norris, R.M.; John, M.B.; Hurley, P.J.

    1975-01-01

    The relationship between regional blood flow and epicardial S-T segment elevation was studied in 26 open-chest anesthetized dogs with left anterior coronary artery ligations. Changes in myocardial blood flow, measured with 15 +- 5 μ (diameter) microspheres labeled with 141 Ce, 85 Sr, and 169 Yb, were correlated with summated S-T segment elevations 15 minutes, 1 hour, and 2 hours after coronary artery occlusion. In normal areas, myocardial blood flow was 113 +- 5 ml/min 100 g -1 and summated S-T segment elevation was 0.3 +- 0.2 mv. Fifteen minutes after coronary artery occlusion in 26 dogs, S-T segment elevation was 5.7 +- 0.7 mv over the center of the infarct and myocardial blood flow was 10 +- 1 ml/min 100 g -1 ; over the border zone, myocardial blood flow was 63 +- 4 ml/min 100 g -1 and S-T segment elevation was 3.1 +- 0.1 mv. One third of the areas with a myocardial blood flow of 10 ml/min 100 g -1 or less had no S-T segment elevation. In the center and border zones of the infarct in 9 dogs, myocardial blood flow increased from 11 +- 2 and 67 +- 8 ml/min 100 g -1 15 minutes after occlusion to 20 +- 4 and 84 +- 12 ml/min 100 g -1 , respectively, 2 hours after coronary artery occlusion. These increases were not associated with a significant reduction in summated S-T segment elevation. The results do not suggest a simple quantitative relationship between epicardial S-T segment elevation and myocardial blood flow following acute coronary artery occlusion

  7. A segmented K-space velocity mapping protocol for quantification of renal artery blood flow during breath-holding

    Thomsen, C; Cortsen, M; Söndergaard, L

    1995-01-01

    for renal artery flow determination. The protocol uses 16 phase-encoding lines per heart beat during 16 heart cycles and gives a temporal velocity resolution of 160 msec. Comparison with a conventional ECG-triggered velocity mapping protocol was made in phantoms as well as in volunteers. In our study, both...... methods showed sufficient robustness toward complex flow in a phantom model. In comparison with the ECG technique, the segmentation technique reduced vessel blurring and pulsatility artifacts caused by respiratory motion, and average flow values obtained in vivo in the left renal artery agreed between......Two important prerequisites for MR velocity mapping of pulsatile motion are synchronization of the sequence execution to the time course of the flow pattern and robustness toward loss of signal in complex flow fields. Synchronization is normally accomplished by using either prospective ECG...

  8. Measurement of stenotic rate and blood flow of carotid artery of the dogs with digital subtraction angiography

    Kobayashi, Keisuke; Kagawa, Masaaki; Asai, Masaaki; Yasue, Hiroshi; Kawabata, Kazuhiro; Yue, Shuzengmr

    1987-01-01

    Hemodynamic analysis of stenotic rate and local mean blood flow of the common carotid artery of the dogs with electromagnetic flowmeter and DSA was evaluated. Measurement of stenotic rate using local profile curve was very accurate and it was though to be useful in evaluation of local blood flow of the cervical carotid artery in the patients with carotid stenosis pre-and postoperatively. Although the measurement of absolute blood flow in the case of known diameter of the vessel is exactly reliable, the measured flow is not so reliable in the clinical application for the difficulty in the accurate measurement of the diameter. But hemodynamic analysis of the relative blood flow in the clinical ground can be estimated from this study. The theory and practical measurement are discussed. (author)

  9. Correlation between the umbilical artery flow ultrasound parameters of intrauterine fetal distress and fetal ischemic hypoxic damage

    Hai-Ying Gu

    2017-08-01

    Full Text Available Objective: To study the correlation between the umbilical artery flow ultrasound parameters of intrauterine fetal distress and fetal ischemic hypoxic damage. Methods: A total of 158 puerperae who gave birth in our hospital between July 2016 and June 2017 were selected and divided into the intrauterine distress group (Apgar<7 points and normal pregnancy group (Apgar≥7 points according to the neonatal Apgar score, the umbilical artery flow ultrasound parameters at 24-30 weeks, 31-36 weeks and 37-41 weeks of gestation were determined, and the umbilical arterial blood gas parameters and oxidative stress molecule levels were determined. Results: At 24-30 weeks, 31-36 weeks and 37-41 weeks of gestation, umbilical arterial RI, PI and S/D of intrauterine distress group were significantly higher than those of normal pregnancy group; umbilical arterial pH and PaO2 of intrauterine distress group were significantly lower than those of normal pregnancy group and negatively correlated with RI, PI and S/D while PaCO2 and lactic acid levels were significantly higher than those of normal pregnancy group and positively correlated with RI, PI and S/D; SOD, GSH-px and CAT levels in umbilical artery of intrauterine distress group were significantly lower than those of normal pregnancy group and negatively correlated with RI, PI and S/D while MDA and 8-OHdG levels were significantly higher than those of normal pregnancy group and positively correlated with RI, PI and S/D. Conclusion: Umbilical artery flow ultrasound characteristics of intrauterine fetal distress are characterized by the increased resistance and decreased blood flow and are correlated with the degree of fetal hypoxia and oxidative stress.

  10. Tuberculosis ocular

    Francisco Infante Barrera

    1950-01-01

    Full Text Available La evolución etiológica de la medicina la podemos dividir en dos grandes períodos: período de la sífilis y período de la tuberculosis. El período de la sífilis, gracias a las armas de combate de que hoy disponemos, ocupa un lugar secundario. El período de la tuberculosis y que no es sino el paralelo de la vida moderna, ocupa en vigencia el primer lugar. Es el período presente. Hasta hace poco tiempo el médico en general, iniciaba la exploración de su paciente con un interrogatorio, una inspección, un tacto y una serología con una obsesión sifilítica. En la época actual el médico y en especial el oftalmólogo debe tener una obsesión tuberculosa en la investigación etiológica. Cuántas veces en una afección ocular que de una manera lenta pero progresiva produce profundas alteraciones oculares, lleva el sello soterrado de una tuberculosis? Cuántos enfermos de una constitución en apariencia envidiable hacen precisamente por un exceso de sus defensas una alergia tuberculosa? Tan traicionera como la sífilis es la tuberculosis. La sífilis quema sus etapas y estalla con una hemorragia cerebral, una locura, una parálisis general, una ataxia locomotriz progresiva, una goma o una meningitis sifilítica. La tuberculosis hace su presentación con una afección ocular, una goma, una granulia, una artritis, una osteítis, o una meningitis óptico-quiasmática. Siendo esto así, es necesario, en la mayoría de las afecciones oculares, tratar de identificarla por los medios de diagnóstico de que hoy disponemos.

  11. Fractional flow reserve is not associated with inflammatory markers in patients with stable coronary artery disease.

    Jan-Willem E M Sels

    Full Text Available BACKGROUND: Atherosclerosis is an inflammatory condition and increased blood levels of inflammatory biomarkers have been observed in acute coronary syndromes. In addition, high expression of inflammatory markers is associated with worse prognosis of coronary artery disease. The presence and extent of inducible ischemia in patients with stable angina has previously been shown to have strong prognostic value. We hypothesized that evidence of inducible myocardial ischemia by local lesions, as measured by fractional flow reserve (FFR, is associated with increased levels of blood based inflammatory biomarkers. METHODS: Whole blood samples of 89 patients with stable angina pectoris and 16 healthy controls were analyzed. The patients with stable angina pectoris underwent coronary angiography and FFR of all coronary lesions. We analyzed plasma levels of cytokines IL-6, IL-8 and TNF-α and membrane expression of Toll-like receptor 2 and 4, CD11b, CD62L and CD14 on monocytes and granulocytes as markers of inflammation. Furthermore, we quantified the severity of hemodynamically significant coronary artery disease by calculating Functional Syntax Score (FSS, an extension of the Syntax Score. RESULTS: For the majority of biomarkers, we observed lower levels in the healthy control group compared with patients with stable angina who underwent coronary catheterization. We found no difference for any of the selected biomarkers between patients with a positive FFR (≤ 0.75 and negative FFR (>0.80. We observed no relationship between the investigated biomarkers and FSS. CONCLUSION: The presence of local atherosclerotic lesions that result in inducible myocardial ischemia as measured by FFR in patients with stable coronary artery disease is not associated with increased plasma levels of IL-6, IL-8 and TNF-α or increased expression of TLR2 and TLR4, CD11b, CD62L and CD14 on circulating leukocytes.

  12. Flow-related Right Ventricular - Pulmonary Arterial Pressure Gradients during Exercise.

    Wright, Stephen P; Opotowsky, Alexander R; Buchan, Tayler A; Esfandiari, Sam; Granton, John T; Goodman, Jack M; Mak, Susanna

    2018-06-06

    The assumption of equivalence between right ventricular and pulmonary arterial systolic pressure is fundamental to several assessments of right ventricular or pulmonary vascular hemodynamic function. Our aims were to 1) determine whether systolic pressure gradients develop across the right ventricular outflow tract in healthy adults during exercise, 2) examine the potential correlates of such gradients, and 3) consider the effect of such gradients on calculated indices of right ventricular function. Healthy untrained and endurance-trained adult volunteers were studied using right-heart catheterization at rest and during submaximal cycle ergometry. Right ventricular and pulmonary artery pressures were simultaneously transduced, and cardiac output was determined by thermodilution. Systolic pressures, peak and mean gradients, and indices of chamber, vascular, and valve function were analyzed offline. Summary data are reported as mean ± standard deviation or median [interquartile range]. No significant right ventricular outflow tract gradients were observed at rest (mean gradient = 4 [3-5] mmHg), and calculated effective orifice area was 3.6±1.0 cm2. Right ventricular systolic pressure increases during exercise were greater than that of pulmonary artery systolic pressure. Accordingly, mean gradients developed during light exercise (8 [7-9] mmHg) and increased during moderate exercise (12 [9-14] mmHg, p < 0.001). The magnitude of the mean gradient was linearly related to cardiac output (r2 = 0.70, p < 0.001). In healthy adults without pulmonic stenosis, systolic pressure gradients develop during exercise, and the magnitude is related to blood flow rate.

  13. Significance of the Hepatic Artery Anatomy and Radionuclide Flow Data for the Technique and Results of Intra-arterial Infusion Chemotherapy in Patients with Liver Neoplasms

    Vaicekavicius, E.; Satkevicius, Z.; Kiudelis, J. and others

    2002-01-01

    The aim of this study was to evaluate the impact of different variations of liver vascular anatomy and hemodynamics in achieving the maximum effect of the hepatic artery infusion chemotherapy (HAIC) in patients with primary or metastatic hepatic malignancies. The retrograde analysis of hepatic artery (HA) anatomy and of radionuclide flow data on 23 patients treated by HAIC was performed. The HA anatomy was analysed according to two classification systems: the first one proposed by Michels, which describes 10 variants, and the second one proposed by Suzuki, which describes 3 variants - single, double or multiple HA with 3 subtypes of each variant (celiac, mesenteric and mixed). Additionally, before starting HAIC, 99mTc human macroalbumin was injected through the catheter at a slow rate into the HA of 10 patients with abnormal variants of HA anatomy. Radionuclide testing was performed with the aim to evaluate the subsequent intrahepatic distribution of chemotherapy agents. The intra-arterial regimen of HAIC for all patients consisted of a 5-day infusion of 5-ftorouracil or floxuridine with addition of doxorubicin or cisplatin. Such treatment was repeated every 3-4 weeks 3-6 times for every patient. The typical anatomy of HA branching was seen in 12 (52.2%) patients. The double origin of HA (according to Suzuki's classification) was seen in 9 (39.1%). In 5 (21.7%) of them the right HA was coming out from the superior mesenteric artery. In the remaining 4 (17.4%) patients the left HA was coming out from the left gastric artery. In one patient, multiple HA were observed, and there was no possibility to perform HAIC at all. The preliminary embolization of one of HA was performed in 3 patients with double HA according to Suzuki's classification. Redistribution of hepatic flow through intrahepatic collaterals was achieved in all 3 patients and assessed by radionuclide examination. The aberrant left HA was not embolized in 4 patients, because the metastatic tumours were

  14. Effects of iodinated contrast media on common carotid and brachial artery blood flow and wall shear stress

    Irace, C.; Tamburini, S.; Bertucci, B.; Franceschi, M.S. de; Gnasso, A.

    2006-01-01

    The aim of our study was to evaluate the effect of the intravenous contrast media iomeprol on wall shear stress, blood flow and vascular parameters in the common carotid and brachial artery. Thirty outpatients undergoing thoracic or abdominal spiral CT scans were studied. The internal diameter and flow velocity of the common carotid and brachial artery were evaluated by ultrasound, and blood viscosity was measured before and after low osmolality iomeprol (Iomeron 350) injection. The wall shear stress, blood flow and pulsatility index were calculated. To test the differences between groups, the Wilcoxon rank test and Mann Whitney U test were applied. Blood viscosity decreased slightly, but significantly after contrast media (4.6±0.7 vs. 4.5±0.7 mPa.s, P=0.02). Contrarily, blood flow and wall shear stress did not change in the common carotid artery, but significantly decreased in the brachial artery (0.9±0.4 vs. 0.6±0.3 ml/s, P<0.0001, and 41.5±13.9 vs. 35.3±11.0 dynes/cm2, P<0.002, respectively), whereas the pulsatility index significantly increased in the brachial artery (5.0±3.3 vs. 7.5±5.3, P<0.001). Iomeprol injection causes blood flow and wall shear stress reduction of the brachial artery; the rise in the pulsatility index suggests an increase in peripheral vascular resistance. Further investigation is needed to evaluate whether these modifications can be clinically relevant. (orig.)

  15. Absent end diastolic flow of umbilical artery Doppler: pregnancy outcome in 62 cases.

    Poulain, P; Palaric, J C; Milon, J; Betremieux, P; Proudhon, J F; Signorelli, D; Grall, J Y; Giraud, J R

    1994-02-01

    We retrospectively studied the outcome of pregnancy in 62 cases of absent end diastolic flow (AEDF) of umbilical artery Doppler flow velocity waveform. The history of pregnancies revealed that nearly all were of high risk. Many cases presented cerebral (65%) or uterine (55.5%) Doppler flow abnormalities, or both (38%). We noted 10 fetal deaths and decided 7 pregnancy terminations. Malformation and chromosomal defect rate was 16%. We noted 44 (71%) live-births, a very high rate of cesarean section (86%), prematurity (75%), small for gestational age (39%). Forty-five percent of the neonates had a 1-min Apgar score under 7, which dropped to 27% at 5 min. Neonate mortality rate was 6.9% and the total mortality rate was 34% (21/62). Morbidity was significant (7 cases with severe morbidity, 2 cases with chromosomal abnormality of poor prognosis). We compared different sub-groups with a view to looking for some prenatal factors which predict poor neonatal outcome in case of AEDF.

  16. Analysis of placenta vascularization in patients with uterine altered artery Doppler flow velocity exams.

    Gilio, Daniel Bruno; Miranda Corrêa, Rosana Rosa; Souza de Oliveira Guimarães, Camila; Peres, Luiz Cesar; Marques Salge, Ana Karina; Cavellani, Camila Lourencini; de Paula Antunes Teixeira, Vicente; Costa da Cunha Castro, Eumenia

    2009-08-01

    One of the frequent questions in obstetric practice is to determine placental vascular changes that may account for abnormal Doppler flow velocity alterations in maternal uterine vessels from women and fetuses without pregnancy pathology. A retrospective morphometric study was realized using 27 placentas from patients submitted for Doppler flow velocity exam during pregnancy. The placentas were morphologically examined using hematoxylin-eosin staining. Measurements of villi were made with the use of a video camera coupled to a common light microscope and a computer with automatic image analyzing software. Of the 27 placentas, 13 (48%) were of patients showing unaltered Doppler and 14 (52%) showing altered Doppler. The number of stem villi vessels was significantly larger in the placentas of patients with Doppler exam alterations (P = 0.003). This group also presented greater stem villi vessel thickness, although without significant difference. The number of intermediary and terminal villi vessels was greater in the placentas of patients with altered Doppler exams (P < 0.001), and a greater terminal villi area was observed in these cases (P < 0.001). The morphological proof that uterine artery Doppler flow velocity exam alterations are associated with placental vascular alterations demonstrates the importance of this exam during prenatal care, even in the absence of maternal-fetal alterations.

  17. Numerical analysis of blood flow in realistic arteries subjected to strong non-uniform magnetic fields

    Kenjeres, Sasa

    2008-01-01

    The paper reports on a comprehensive mathematical model for simulations of blood flow under the presence of strong non-uniform magnetic fields. The model consists of a set of Navier-Stokes equations accounting for the Lorentz and magnetisation forces, and a simplified set of Maxwell's equations (Biot-Savart/Ampere's law) for treating the imposed magnetic fields. The relevant hydrodynamic and electromagnetic properties of human blood were taken from the literature. The model is then validated for different test cases ranging from a simple cylindrical geometry to real-life right-coronary arteries in humans. The time-dependency of the wall-shear-stress for different stenosis growth rates and the effects of the imposed strong non-uniform magnetic fields on the blood flow pattern are presented and analysed. It is concluded that an imposed non-uniform magnetic field can create significant changes in the secondary flow patterns, thus making it possible to use this technique for optimisations of targeted drug delivery

  18. Relationship between segmental thallium-201 uptake and regional myocardial blood flow in patients with coronary artery disease

    Nichols, A.B.; Weiss, M.B.; Sciacca, R.R.; Cannon, P.J.; Blood, D.K.

    1983-01-01

    The relationship between the spatial distribution of thallium-201 in myocardial perfusion scintigrams and the distribution of left ventricular regional myocardial blood flow was examined in 25 patients undergoing coronary arteriography. Thallium-201 myocardial scintigrams were obtained after symptom-limited exercise and after a 4 hr delay. Regional myocardial blood flow was measured by the xenon-133 clearance method in patients at rest and during rapid atrial pacing to a double product comparable with that achieved during exercise stress testing. Patterns of regional thallium-201 activity and regional myocardial blood flow, recorded in similar left anterior oblique projections, were compared for left ventricular segments supplied by the left anterior descending (LAD) and left circumflex (CIRC) arteries. In 11 patients without significant lesions of the left coronary artery (group 1), thallium-201 was homogeneously distributed in the LAD and CIRC distributions in scintigrams taken during peak exercise; these scintigrams correspond to homogeneous regional myocardial blood flow in the LAD and CIRC regions during pacing-induced stress. In 14 patients with significant lesions of the left coronary artery (group 2), ratios of regional thallium-201 activity in the LAD and CIRC distributions of exercise scintigrams correlated well (r . .84) with ratios of regional myocardial blood flow measured during rapid pacing. Background subtraction altered the relationship between relative thallium-201 uptake and regional myocardial blood flow, causing overestimation of the magnitude of flow reduction on exercise scintigrams

  19. Dependency of cerebral blood flow upon mean arterial pressure in patients with acute bacterial meningitis

    Møller, Kirsten; Larsen, Fin Stolze; Qvist, Jesper

    2000-01-01

    Diseases, Copenhagen University Hospital, Denmark. PATIENTS: Sixteen adult patients with acute bacterial meningitis. INTERVENTION: Infusion of norepinephrine to increase MAP. MEASUREMENTS: During a rise in MAP induced by norepinephrine infusion, we measured relative changes in CBF by transcranial Doppler......OBJECTIVE: Patients with acute bacterial meningitis are often treated with sympathomimetics to maintain an adequate mean arterial pressure (MAP). We studied the influence of such therapy on cerebral blood flow (CBF). DESIGN: Prospective physiologic trial. SETTING: The Department of Infectious....... Autoregulation was classified as impaired if Vmean increased by >10% per 30 mm Hg increase in MAP and if no lower limit of autoregulation was identified by the computer program; otherwise, autoregulation was classified as preserved. MAIN RESULTS: Initially, Vmean increased from a median value of 46 cm/sec (range...

  20. Asymptotic analysis of blood flow in stented arteries: time dependency and direct simulations***

    Pichon Gostaf Kirill

    2010-12-01

    Full Text Available This work aims to extend in two distinct directions results recently obtained in [10]. In a first step we focus on the possible extension of our results to the time dependent case. Whereas in the second part some preliminary numerical simulations aim to give orders of magnitudes in terms of numerical costs of direct 3D simulations. We consider, in the first part, the time dependent rough problem for a simplified heat equation in a straight channel that mimics the axial velocity under an oscillating pressure gradient. We derive first order approximations with respect to ϵ, the size of the roughness. In order to understand the problem and set up correct boundary layer approximations, we perform a time periodic fourier analysis and check that no frequency can interact with the roughness. We show rigorously on this toy problem that the boundary layers remain stationary in time (independent on the frequency number. Finally we perform numerical tests validating our theoretical approach. In the second part, we determine actual limits, when running three-dimensional blood flow simulations of the non-homogenized stented arteries. We solve the stationary Stokes equations for an artery containing a saccular aneurysm. Consecutive levels of uniform mesh refinement, serve to relate spatial resolution, problem scale, and required computation time. Test computations are presented for femoral side aneurysm, where a simplified ten-wire stent model was placed across the aneurysm throat. We advocate the proposed stent homogenization model, by concluding that an actual computation power is not sufficient to run accurate, direct simulations of a pulsatile flow in stented vessels.

  1. Analysis of digital subtraction angiography for estimating flow reserve in critical coronary artery stenosis

    Kotoku, Shinya; Matsuzaki, Masunori; Otani, Nozomi

    1988-01-01

    To assess the accuracy of digital subtraction angiography in evaluating coronary flow reserve in cases with critical coronary artery stenosis, time-density curves were obtained from digital subtraction coronary angiograms in the myocardial region of interest. Time to peak contrast (TPC) and time constant of the washout exponential curve (T) were measured in 14 patients with stable effort angina pectoris and critical one vessel lesion before and after percutaneous transluminal coronary angioplasty (PTCA). All patients had normal left ventricular ejection fraction (59±7%) and 201 Tl myocardial images at rest. The values of TPC and T were significantly shortened from 5.4±1.3 to 4.5±1.0 sec (p<0.02) and from 10.9±3.8 to 5.3±1.3 sec (p<0.001) after PTCA, respectively. However, in 9 patients TPC values were approximately the same before and after PTCA. In five experimental dogs with critical circumflex coronary artery stenosis, coronary flow (CF; Doppler flowmeter) and systolic thickening of the posterior wall (by sonomicrometry) at rest did not differ from those of the controls. However, contrast media-induced reactive hyperemia was markedly attenuated, accompanied by a significant increase in T (7.7±4.5 vs 15.8±10.9 sec, p<0.01) and totally unchanged TPC (both 6.8 sec). With simultaneous tracings of CF and time-density curves, TPC and washout phases corresponded with contrast-induced transient CF reduction and hyperemic phases, respectively. We concluded that T may be more sensitive for estimating CF maintained nearly normal, e.g., in patients with stable effort angina pectoris having normal left ventricular wall motion at rest. (author)

  2. Influence of hemodialysis on the mean blood flow velocity in the middle cerebral artery.

    Stefanidis, I; Bach, R; Mertens, P R; Liakopoulos, V; Liapi, G; Mann, H; Heintz, B

    2005-08-01

    Several effects of hemodialysis, including hemoconcentration, alterations of hemostasis or hemorheology and endothelial activation, could potentially interfere with cerebral blood flow (CBF) regulation. These treatment-specific changes may also be crucial for the enhanced incidence of stroke in uremic patients. Nevertheless, the influence of hemodialysis on CBF has not been yet adequately studied. We registered mean blood flow velocity (MFV) in the middle cerebral artery (MCA) during hemodialysis treatment in order to evaluate its contribution on CBF changes. Transcranial Doppler ultrasonography (TCD) of the MCA was performed continuously during hemodialysis treatment in 18 stable patients (10 males and 8 females, mean age 62 +/- 11 years) with end-stage renal disease of various origin. Blood pressure (mmHg), heart rate (/min), ultrafiltration volume (ml), BV changes (deltaBV by hemoglobinometry, %), arterial blood gases (pO2, blood oxygen content, pCO2), hemostasis activation (thrombin-antithrombin III complex, ELISA) and fibrinogen (Clauss) were measured simultaneously at the beginning of treatment and every hour thereafter. Before the hemodialysis session the MFV in the MCA was within normal range (57.5 +/- 13.0 cm/s, ref. 60 +/- 12) and was mainly dependent on the patients' age (r = -0.697, p delta%MFV) were interrelated to the ultrafiltration volume (r = -0.486, p delta%acO2, r = -0.420, p delta%fibrinogen, r = 0.244, p < 0.05). A significant continuous decrease of the MFV in the MCA was observed during hemodialysis treatment, which inversely correlated both with ultrafiltration volume, BV changes and changes of plasma fibrinogen. The ultrafiltration-induced hemoconcentration with concomitant rise of hematocrit and oxygen transport capacity, may partly explain the alterations in the cerebral MFV observed during hemodialysis.

  3. Acute arterial occlusion - kidney

    ... main artery to the kidney is called the renal artery. Reduced blood flow through the renal artery can hurt kidney function. ... need include: Duplex Doppler ultrasound exam of the renal arteries to test blood flow MRI of the kidney arteries, which can show ...

  4. Blood flow of the right and left submandibular gland during unilateral carotid artery occlusion in rat: role of nitric oxide.

    Vág, J; Hably, C; Fazekas, A; Bartha, J

    1999-01-01

    The aim of the present study was to investigate the effect of unilateral carotid artery occlusion on the blood flow of submandibular gland in anesthetized rats and identify the role of nitric oxide (NO) in blood flow changes after the artery occlusion. L-NAME (N omega-nitro-L-arginine-methyl-ester; 10 mg/kg/day, per os) dissolved in tap water was used to block nitric oxide synthase. Glandular blood flow was measured using Sapirstein's indicator (86Rb) distribution technique. In the control animals the blood flow of left (ligated side) submandibular gland was lower than in the right (unligated side) one (right: 76.4+/-15.4 ml/min/100 g, 64.1+/-13.4 ml/min/100 g, ptinder this condition.

  5. Comparison of two-dimensional MR angiography and microsphere measurement of renal blood flow for detection of renal artery stenosis

    Powers, T.A.; Lorenz, C.H.; Shetty, A.N.; Holburn, G.E.; Price, R.R.

    1990-01-01

    This paper compares depiction of the renal arteries by MR angiography to renal blood flow as determined with microspheres in a dog model of renal artery stenosis. A left renal artery stenosis was created by placement of a silk ligature. Nb-95-labeled microspheres were injected into the left ventricle and a reference blood sample was drawn. The dog was imaged in the 1.5-T MR imager with two-dimensional MR angiography sequences. The kidneys were excised, weighted, divided into sections, and counted. Two dogs were studied to date. In dog 1, left renal blood flow (RBF) was 42 mL/min/100 g and right RBF was 337 mL/min/100 g. In dog 2 left RBF was 44 mL/min/100 g and right RBF was 608 mL/min/100 g

  6. Decreased muscle oxygenation and increased arterial blood flow in the non-exercising limb during leg exercise.

    Shiroishi, Kiyoshi; Kime, Ryotaro; Osada, Takuya; Murase, Norio; Shimomura, Kousuke; Katsumura, Toshihito

    2010-01-01

    We evaluated arterial blood flow, muscle tissue oxygenation and muscle metabolism in the non-exercising limb during leg cycling exercise. Ten healthy male volunteers performed a graded leg cycling exercise at 0, 40, 80, 120 and 160 watts (W) for 5 min each. Tissue oxygenation index (TOI) of the non-exercising left forearm muscle was measured using a near-infrared spatially resolved spectroscopy (NIR(SRS)), and non-exercising forearm blood flow ((NONEX)FBF) in the brachial artery was also evaluated by a Doppler ultrasound system. We also determined O(2) consumption of the non-exercising forearm muscle (NONEXV(O)(2mus)) by the rate of decrease in O(2)Hb during arterial occlusion at each work rate. TOI was significantly decreased at 160 W (p exercising muscle may be reduced, even though (NONEX)FBF increases at high work rates during leg cycling exercise.

  7. Mean blood velocities and flow impedance in the fetal descending thoracic aortic and common carotid artery in normal pregnancy.

    Bilardo, C M; Campbell, S; Nicolaides, K H

    1988-12-01

    A linear array pulsed Doppler duplex scanner was used to establish reference ranges for mean blood velocities and flow impedance (Pulsatility Index = PI) in the descending thoracic aorta and in the common carotid artery from 70 fetuses in normal pregnancies at 17-42 weeks' gestation. The aortic velocity increased with gestation up to 32 weeks, then remained constant until term, when it decreased. In contrast, the velocity in the common carotid artery increased throughout pregnancy. The PI in the aorta remained constant throughout pregnancy, while in the common carotid artery it fell steeply after 32 weeks. These results suggest that with advancing gestation there is a redistribution of the fetal circulation with decreased impedance to flow to the fetal brain, presumably to compensate for the progressive decrease in fetal blood PO2.

  8. First trimester growth restriction and uterine artery blood flow in the second trimester as predictors of adverse pregnancy outcome

    Pedersen, N G; Sperling, L; Wøjdemann, K R

    2013-01-01

    To investigate if fetuses with first trimester growth restriction have poorer perfusion of the placenta compared to a control group, and to investigate whether first trimester growth restriction in combination with poor flow in the uterine arteries in the second trimester can be used to predict...

  9. Renal embolic protection devices improve blood flow after stenting for atherosclerotic renal artery stenosis.

    Paul, Timir K; Lee, John H; White, Christopher J

    2012-11-15

    We sought to measure angiographic renal frame counts (RFC), as a quantitative angiographic assessment of renal blood flow, to evaluate microvascular compromise due to atheroembolism associated with RAS. Atheroembolism associated with renal artery stenting (RAS) has been implicated as a cause for worsening renal function following successful intervention. Use of a distal embolic protection device (EPD) during RAS has been shown to be safe with debris capture in a high percentage of cases. However, objective benefit for renal function with EPD has been difficult to demonstrate. A control group of 30 consecutive patients (33 kidneys) who underwent RAS without EPD were compared with 33 consecutive patients (33 kidneys) who underwent RAS with EPD using RFC measurement. The prestent and poststent mean RFC for the control group was 30.4 ± 12.1 vs. 23.7 ± 9.9 (P = 0.002) and for the EPD group it was 42.6 ± 12.6 vs. 28.3 ± 9.2 (P renal blood flow, manifested by a greater reduction of the RFC (Δ RFC) 14.2 ± 15.2 vs. 6.7 ± 11.7 (P = 0.03) compared with the control group. The use of an EPD was associated with a much larger improvement in renal blood flow (lower RFC) following RAS. This suggests that EPD's may be effective in preventing renal atheroembolic injury and that a controlled trial measuring the impact of EPD's on renal blood flow following RAS should be performed. Copyright © 2012 Wiley Periodicals, Inc.

  10. Alterations of Blood Flow Through Arteries Following Atherectomy and the Impact on Pressure Variation and Velocity.

    Plourde, Brian D; Vallez, Lauren J; Sun, Biyuan; Nelson-Cheeseman, Brittany B; Abraham, John P; Staniloae, Cezar S

    2016-09-01

    Simulations were made of the pressure and velocity fields throughout an artery before and after removal of plaque using orbital atherectomy plus adjunctive balloon angioplasty or stenting. The calculations were carried out with an unsteady computational fluid dynamic solver that allows the fluid to naturally transition to turbulence. The results of the atherectomy procedure leads to an increased flow through the stenotic zone with a coincident decrease in pressure drop across the stenosis. The measured effect of atherectomy and adjunctive treatment showed decrease the systolic pressure drop by a factor of 2.3. Waveforms obtained from a measurements were input into a numerical simulation of blood flow through geometry obtained from medical imaging. From the numerical simulations, a detailed investigation of the sources of pressure loss was obtained. It is found that the major sources of pressure drop are related to the acceleration of blood through heavily occluded cross sections and the imperfect flow recovery downstream. This finding suggests that targeting only the most occluded parts of a stenosis would benefit the hemodynamics. The calculated change in systolic pressure drop through the lesion was a factor of 2.4, in excellent agreement with the measured improvement. The systolic and cardiac-cycle-average pressure results were compared with measurements made in a multi-patient study treated with orbital atherectomy and adjunctive treatment. The agreements between the measured and calculated systolic pressure drop before and after the treatment were within 3%. This excellent agreement adds further confidence to the results. This research demonstrates the use of orbital atherectomy to facilitate balloon expansion to restore blood flow and how pressure measurements can be utilized to optimize revascularization of occluded peripheral vessels.

  11. Intra-arterial digital subtraction angiography of the pulmonary arteries using a flow-directed balloon catheter in the diagnosis of pulmonary embolism

    Rooij, W.J.J. van; Heeten, G.J. den

    1992-01-01

    Selective intra-arterial digital subtraction angiography (IA-DSA) of the pulmonary vessels was performed in 70 patients suspected of acute pulmonary embolism. A flow-directed Swan-Ganz pulmonary angiography catheter was used. The spatial resolution of the equipment used was 3.3 lp/mm for DSA and 6.0 lp/mm for conventional pulmonary angiography (CPA). Image quality of the angiograms was assessed by determining the highest visible branching division of the main pulmonary artery. The mean visible branching division for IA-DSA was 4.71 (range 3-7). In 10 patients where IA-DSA and CPA were performed during the same procedure there was no difference in visualization of peripheral arteries (mean 4.70 visible or for both modalities). IA-DSA makes the procedure rapid, saves on films and contrast material and allows good visualization of areas where exposure is difficult. The spatial resolution of state-of-the-art equipment permits sufficient definition of subsegmental vessels. The use of the flow-directed balloon catheter makes the examination easy to perform and minimizes the risk of catheter induced cardiac arrhythmias. (orig.) [de

  12. Insulin resistance is associated with lower arterial blood flow and reduced cortical perfusion in cognitively asymptomatic middle-aged adults

    Hoscheidt, Siobhan M; Kellawan, J Mikhail; Berman, Sara E; Rivera-Rivera, Leonardo A; Krause, Rachel A; Oh, Jennifer M; Beeri, Michal S; Rowley, Howard A; Wieben, Oliver; Carlsson, Cynthia M; Asthana, Sanjay; Johnson, Sterling C; Schrage, William G

    2016-01-01

    Insulin resistance (IR) is associated with poor cerebrovascular health and increased risk for dementia. Little is known about the unique effect of IR on both micro- and macrovascular flow particularly in midlife when interventions against dementia may be most effective. We examined the effect of IR as indexed by the Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) on cerebral blood flow in macro- and microvessels utilizing magnetic resonance imaging (MRI) among cognitively asymptomatic middle-aged individuals. We hypothesized that higher HOMA-IR would be associated with reduced flow in macrovessels and lower cortical perfusion. One hundred and twenty cognitively asymptomatic middle-aged adults (57 ± 5 yrs) underwent fasting blood draw, phase contrast-vastly undersampled isotropic projection reconstruction (PC VIPR) MRI, and arterial spin labeling (ASL) perfusion. Higher HOMA-IR was associated with lower arterial blood flow, particularly within the internal carotid arteries (ICAs), and lower cerebral perfusion in several brain regions including frontal and temporal lobe regions. Higher blood flow in bilateral ICAs predicted greater cortical perfusion in individuals with lower HOMA-IR, a relationship not observed among those with higher HOMA-IR. Findings provide novel evidence for an uncoupling of macrovascular blood flow and microvascular perfusion among individuals with higher IR in midlife. PMID:27488909

  13. Ocular hemodynamics and glaucoma: the role of mathematical modeling.

    Harris, Alon; Guidoboni, Giovanna; Arciero, Julia C; Amireskandari, Annahita; Tobe, Leslie A; Siesky, Brent A

    2013-01-01

    To discuss the role of mathematical modeling in studying ocular hemodynamics, with a focus on glaucoma. We reviewed recent literature on glaucoma, ocular blood flow, autoregulation, the optic nerve head, and the use of mathematical modeling in ocular circulation. Many studies suggest that alterations in ocular hemodynamics play a significant role in the development, progression, and incidence of glaucoma. Although there is currently a limited number of studies involving mathematical modeling of ocular blood flow, regulation, and diseases (such as glaucoma), preliminary modeling work shows the potential of mathematical models to elucidate the mechanisms that contribute most significantly to glaucoma progression. Mathematical modeling is a useful tool when used synergistically with clinical and laboratory data in the study of ocular blood flow and glaucoma. The development of models to investigate the relationship between ocular hemodynamic alterations and glaucoma progression will provide a unique and useful method for studying the pathophysiology of glaucoma.

  14. Enhancement of automated blood flow estimates (ENABLE) from arterial spin-labeled MRI.

    Shirzadi, Zahra; Stefanovic, Bojana; Chappell, Michael A; Ramirez, Joel; Schwindt, Graeme; Masellis, Mario; Black, Sandra E; MacIntosh, Bradley J

    2018-03-01

    To validate a multiparametric automated algorithm-ENhancement of Automated Blood fLow Estimates (ENABLE)-that identifies useful and poor arterial spin-labeled (ASL) difference images in multiple postlabeling delay (PLD) acquisitions and thereby improve clinical ASL. ENABLE is a sort/check algorithm that uses a linear combination of ASL quality features. ENABLE uses simulations to determine quality weighting factors based on an unconstrained nonlinear optimization. We acquired a set of 6-PLD ASL images with 1.5T or 3.0T systems among 98 healthy elderly and adults with mild cognitive impairment or dementia. We contrasted signal-to-noise ratio (SNR) of cerebral blood flow (CBF) images obtained with ENABLE vs. conventional ASL analysis. In a subgroup, we validated our CBF estimates with single-photon emission computed tomography (SPECT) CBF images. ENABLE produced significantly increased SNR compared to a conventional ASL analysis (Wilcoxon signed-rank test, P Wilcoxon signed-rank test, P < 0.0001) and this similarity was strongly related to ASL SNR (t = 24, P < 0.0001). These findings suggest that ENABLE improves CBF image quality from multiple PLD ASL in dementia cohorts at either 1.5T or 3.0T, achieved by multiparametric quality features that guided postprocessing of dementia ASL. 2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;47:647-655. © 2017 International Society for Magnetic Resonance in Medicine.

  15. Assessment of resting-state blood flow through anterior cerebral arteries using trans-cranial doppler recordings.

    Huang, Hanrui; Sejdić, Ervin

    2013-12-01

    Trans-cranial Doppler (TCD) recordings are used to monitor cerebral blood flow in the main cerebral arteries. The resting state is usually characterized by the mean velocity or the maximum Doppler shift frequency (an envelope signal) by insonating the middle cerebral arteries. In this study, we characterized cerebral blood flow in the anterior cerebral arteries. We analyzed both envelope signals and raw signals obtained from bilateral insonation. We recruited 20 healthy patients and conducted the data acquisition for 15 min. Features were extracted from the time domain, the frequency domain and the time-frequency domain. The results indicate that a gender-based statistical difference exists in the frequency and time-frequency domains. However, no handedness effect was found. In the time domain, information-theoretic features indicated that mutual dependence is higher in raw signals than in envelope signals. Finally, we concluded that insonation of the anterior cerebral arteries serves as a complement to middle cerebral artery studies. Additionally, investigation of the raw signals provided us with additional information that is not otherwise available from envelope signals. Use of direct trans-cranial Doppler raw data is therefore validated as a valuable method for characterizing the resting state. Copyright © 2013 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

  16. Contribution of spiral artery blood flow changes assessed by transvaginal color Doppler sonography for predicting endometrial pathologies

    Suna Kabil Kucur

    2013-01-01

    Full Text Available ive: To investigate the diagnostic value of blood flow measurements in spiral artery by transvaginal color Doppler sonography (CDS in predicting endometrial pathologies.Methods: Ninety-seven patients presenting with abnormal uterine bleeding and requiring endometrial assessment were included in this prospective observational study. Endometrial thickness, structure and echogenicity were recorded. Pulsatility index (PI and resistive index (RI of the spiral artery were measured by transvaginal CDS. Endometrial sampling was performed for all subjects. Sonographic and hystopathologic findings were compared.Results: The histopathological diagnoses were as follows; 39 cases (40.2% endometrial polyp, 9 cases (9.3% endometrial hyperplasia, 10 cases (10.3 submucous myoma, 7 cases (7.2% endometrium cancer, and 32 cases (33% nonspecific findings. The spiral artery PI in endometrium cancer group was highly significantly lower than other groups (p<0.01. The spiral artery RI was also significantly lower in the patients with malignant histology (p<0.05. Conclusion: Endometrial pathologies are associated significantly with endometrial spiral artery Doppler changes.Key words: Spiral artery, Doppler ultrasonography, endometrium

  17. Estimation of the Arterial Fraction of Total Hepatic Flow from Radionuclide Angiogram Using 99mTc-DISIDA

    Lee, Hae Gin; Lim, Gye Yeon; Yang, Il Kwon; Kim, Hack Hee; Lim, Jung Ik; Bahk, Yong Whee; Han, Sok Won; Han, Nam Ik; Lee, Young Sok

    1991-01-01

    Arterial fraction of total hepatic blood flow was estimated by a new method, slope method, on radionuclide angiogram using 99m Tc-DISIDA and was compared with that from 99m Tc-Phytate radionuclide angiogram. This study included 11 of normal subjects, 37 of intermediate group with various liver diseases, and 25 patients with liver cirrhosis. We analyzed the data with slope method from radionuclide angiograms and the results were compared with hepatic arterial fractions from uptake method, introduced by Lee et al. at 1986. The hepatic arterial fractions from radionuclide angiograms using 99m Tc-DISIDA and 99m Tc- Phytate were 0.32 ± 0.09 and 0.31 ± 0.11 respectively in normal subjects, and 0.75 ± 0.18 and 0.77 ± 0.21 respectively in patients with liver cirrhosis. The hepatic arterial fractions by the slope method was well correlated with those of the uptake method on 99m Tc-DISIDA scan. There was high correlation between the hepatic arterial fractions from 99m Tc-DISIDA and 99m Tc-Phytate scans. Hepatic arterial fraction estimated by the slope method is a useful index for the diagnosis of liver cirrhosis and the evaluation of status of portal hypertension.

  18. Safety and Efficacy of a Novel Technique in the Use of Fractional Flow Reserve in Complex Coronary Artery Lesions

    Wen-Ming He

    2015-01-01

    Full Text Available Background: Fractional flow reserve (FFR has become an increasingly important index when making decisions with respect to revascularization of coronary artery stenosis. However, the pressure guidewire used in obtaining FFR measurements is difficult to control and manipulate in certain complex coronary artery lesions, resulting in increased fluoroscopy time and contrast dye usage. This study examined a novel (NOV technique for obtaining FFR measurements in hope of easing the difficulties associated with evaluating and treating complex coronary artery lesions. Methods: Fifty-six patients with complex coronary artery lesions were assigned to a conventional (CON FFR technique group or a NOV FFR technique group. The NOV technique involved the use of a balloon and wire exchange within the coronary artery. The fluoroscopy time, contrast dye usage, and FFR-related complications were assessed after completing the FFR measurement procedure for each patient. Results: The median time required for fluoroscopy in the NOV technique group was significantly less than that in the CON technique group; additionally, lesser amounts of contrast dye were used in the NOV technique group (both P 0.05. Conclusions: Compared to the CON technique used for measuring FFR, the new technique reduced the fluoroscopy time and amount of contrast dye used when evaluating complex coronary artery lesions. The new technique did not increase the risk of operation or decrease the success rate.

  19. [The relationship between ophthalmic nerve lesion in glaucoma and ocular and systemic haemodynamic disturbance].

    Liu, L; Yuan, S; Yang, W

    1999-04-01

    To explore the relationship between the optic nerve lesion in glaucoma and ocular and systemic haemodynamic disturbance. The color Doppler imaging was used to study blood velocity in the ophthalmic, the central retinal and the short posterior ciliary arteries in 34 patients with primary open angle glaucoma, 31 patients with low tension glaucoma and 90 healthy controls. The peak systolic velocity(PSV), the end diastolic velocity (EDV) and resistive index (RI) in each artery were measured, moreover the nailfold microcirculation and blood viscosity in each patient were examined. Compared with the control group, the PSV and EDV of the central retinal arteries were significantly lower while the RI of the central retinal arteries was significantly higher in both POAG and LTG patients. The RI of the short posterior ciliary arteries however was significantly higher in POAG. Nailfold microcirculation shows that some important parameters, including flow pattern, loop surrounding, morphological weighted value, total weighted value and capillary deformity rate in the two glaucoma groups were higher, whereas the flow velocity was lower than in the control group. The plasm viscosity and the whole blood viscosity (low spear) were higher than normal. According to our measurements, the nailfold microcirculation and blood viscosity was worse at the end stage of glaucoma than at early stage. The correlative analysis between measurement results of color doppler imaging and microcirculation and heamorrheology showed that nailfold microcirculation morphological weighted value was negatively correlated with the EDV of the central retinal artery and positively correlated with the RI of the central retinal artery in LTG patients. The abnormity of ocular haemodynamics and systemic microcirculation and blood viscosity is one important factor of optic nerve damage in glaucoma.

  20. Middle cerebral artery blood flow velocity during beach chair position for shoulder surgery under general anesthesia.

    Hanouz, Jean-Luc; Fiant, Anne-Lise; Gérard, Jean-Louis

    2016-09-01

    The goal of the present study was to examine changes of middle cerebral artery (VMCA) blood flow velocity in patients scheduled for shoulder surgery in beach chair position. Prospective observational study. Operating room, shoulder surgery. Fifty-three consecutive patients scheduled for shoulder surgery in beach chair position. Transcranial Doppler performed after induction of general anesthesia (baseline), after beach chair positioning (BC1), during surgery 20minutes (BC2), and after back to supine position before stopping anesthesia (supine). Mean arterial pressure (MAP), end-tidal CO2, and volatile anesthetic concentration and VMCA were recorded at baseline, BC1, BC2, and supine. Postoperative neurologic complications were searched. Beach chair position induced decrease in MAP (baseline: 73±10mm Hg vs lower MAP recorded: 61±10mm Hg; P<.0001) requiring vasopressors and fluid challenge in 44 patients (83%). There was a significant decrease in VMCA after beach chair positioning (BC1: 33±10cm/s vs baseline: 39±14cm/s; P=.001). The VMCA at baseline (39±2cm/s), BC2 (35±14cm/s), and supine (39±14cm/s) were not different. The minimal alveolar concentration of volatile anesthetics, end-tidal CO2, SpO2, and MAP were not different at baseline, BC1, BC2, and supine. Beach chair position resulted in transient decrease in MAP requiring fluid challenge and vasopressors and a moderate decrease in VMCA. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. Relation of Long-term Exposure to Air Pollution to Brachial Artery Flow-Mediated Dilation and Reactive Hyperemia

    Wilker, Elissa H.; Ljungman, Petter L.; Rice, Mary B.; Kloog, Itai; Schwartz, Joel; Gold, Diane R.; Koutrakis, Petros; Vita, Joseph A.; Mitchell, Gary F.; Vasan, Ramachandran S.; Benjamin, Emelia J.; Hamburg, Naomi M.; Mittleman, Murray A.

    2014-01-01

    Long-term exposure to ambient air pollution has been associated with cardiovascular morbidity and mortality. Impaired vascular responses may in part explain these findings, but the association of such long-term exposure with measures of both conduit artery and microvascular function have not been widely reported. We evaluated the association between residential proximity to a major roadway (primary or secondary highway) and spatially resolved average fine particulate matter (PM2.5) and baseline brachial artery diameter and mean flow velocity, flow mediated dilation % and hyperemic flow velocity, in the Framingham Offspring and Third Generation Cohorts. We examined 5,112 participants (2,731 (53%) women, mean age 49±14 years). Spatially resolved average PM2.5 was associated with lower flow mediated dilation% and hyperemic flow velocity. An interquartile range difference in PM2.5 (1.99 μg/m3) was associated with −0.16% (95%CI: −0.27%, −0.05%) lower FMD% and −0.72 (95%CI: −1.38, −0.06) cm/s lower hyperemic flow velocity %. Residential proximity to a major roadway was negatively associated with flow mediated dilation %. Compared to living ≥400 m away, living <50 m from a major roadway was associated with 0.32% lower flow mediated dilation (95% confidence interval (CI): −0.58%, −0.06%), but results for hyperemic flow velocity had wide confidence intervals −0.68 cm/s (95%CI: −2.29, 0.93). In conclusion, residential proximity to a major roadway and higher levels of spatially resolved estimates of PM2.5 at participant residences are associated with impaired conduit artery and microvascular function in this large community-based cohort of middle-aged and elderly adults. PMID:24793676

  2. Cerebral small-resistance artery structure and cerebral blood flow in normotensive subjects and hypertensive patients

    De Ciuceis, Carolina; Porteri, Enzo; Rizzoni, Damiano; Boari, Gianluca E.M.; Rosei, Enrico Agabiti [University of Brescia, Clinica Medica, Department of Clinical and Experimental Sciences, Brescia (Italy); Cornali, Claudio; Mardighian, Dikran; Fontanella, Marco M. [University of Brescia, Section of Neurosurgery, Department of Medical and Surgical Specialties, Radiological Sciences and Public Health, Brescia (Italy); Pinardi, Chiara [Spedali Civili, Medical Physics Unit, Brescia (Italy); University of Brescia, Section of Neuroradiology, Department of Medical and Surgical Specialties, Radiological Sciences and Public Health, Brescia (Italy); Rodella, Luigi F.; Rezzani, Rita [University of Brescia, Section of Anatomy, Department of Clinical and Experimental Sciences, Brescia (Italy); Gasparotti, Roberto [University of Brescia, Section of Neurosurgery, Department of Medical and Surgical Specialties, Radiological Sciences and Public Health, Brescia (Italy); University of Brescia, Section of Neuroradiology, Department of Medical and Surgical Specialties, Radiological Sciences and Public Health, Brescia (Italy)

    2014-12-15

    The aim of this study was to prospectively investigate whether the structure of cerebral small-resistance arteries is related to cerebral perfusion parameters as measured with dynamic susceptibility-weighted contrast magnetic resonance imaging (DSC-MRI) in a selected cohort of hypertensive and normotensive patients. Ten hypertensive and 10 normotensive patients were included in the study. All patients underwent neurosurgical intervention for an intracranial tumor and were investigated with DSC-MRI at 1.5 T. Cerebral small-resistance arteries were dissected from a small portion of morphologically normal cerebral tissue and mounted on an isometric myograph for the measurement of the media-to-lumen (M/L) ratio. A quantitative assessment of cerebral blood flow (CBF) and volume (CBV) was performed with a region-of-interest approach. Correlation coefficients were calculated for normally distributed variables. The institutional review board approved the study, and informed consent was obtained from all patients. Compared with normotensive subjects, hypertensive patients had significantly lower regional CBF (mL/100 g/min) in the cortical grey matter (55.63 ± 1.90 vs 58.37 ± 2.19, p < 0.05), basal ganglia (53.34 ± 4.39 vs 58.22. ± 4.33, p < 0.05), thalami (50.65 ± 3.23 vs 57.56 ± 4.45, p < 0.01), subcortical white matter (19.32 ± 2.54 vs 22.24 ± 1.9, p < 0.05), greater M/L ratio (0.099 ± 0.013 vs 0.085 ± 0.012, p < 0.05), and lower microvessel density (1.66 ± 0.67 vs 2.52 ± 1.28, p < 0.05). A statistically significant negative correlation was observed between M/L ratio of cerebral arteries and CBF in the cortical grey matter (r = -0.516, p < 0.05), basal ganglia (r = -0.521, p < 0.05), thalami (r = -0.527 p < 0.05), and subcortical white matter (r = -0.612, p < 0.01). Our results indicate that microvascular structure might play a role in controlling CBF, with possible clinical consequences. (orig.)

  3. Fractional flow reserve versus angiography for guiding percutaneous coronary intervention in patients with multivessel coronary artery disease: 2-year follow-up of the FAME (Fractional Flow Reserve Versus Angiography for Multivessel Evaluation) study

    Pijls, Nico H J; Fearon, William F; Tonino, Pim A L

    2010-01-01

    The purpose of this study was to investigate the 2-year outcome of percutaneous coronary intervention (PCI) guided by fractional flow reserve (FFR) in patients with multivessel coronary artery disease (CAD).......The purpose of this study was to investigate the 2-year outcome of percutaneous coronary intervention (PCI) guided by fractional flow reserve (FFR) in patients with multivessel coronary artery disease (CAD)....

  4. The relationship between exercise-induced muscle fatigue, arterial blood flow and muscle perfusion after 56 days local muscle unloading.

    Weber, Tobias; Ducos, Michel; Mulder, Edwin; Beijer, Åsa; Herrera, Frankyn; Zange, Jochen; Degens, Hans; Bloch, Wilhelm; Rittweger, Jörn

    2014-05-01

    In the light of the dynamic nature of habitual plantar flexor activity, we utilized an incremental isokinetic exercise test (IIET) to assess the work-related power deficit (WoRPD) as a measure for exercise-induced muscle fatigue before and after prolonged calf muscle unloading and in relation to arterial blood flow and muscle perfusion. Eleven male subjects (31 ± 6 years) wore the HEPHAISTOS unloading orthosis unilaterally for 56 days. It allows habitual ambulation while greatly reducing plantar flexor activity and torque production. Endpoint measurements encompassed arterial blood flow, measured in the femoral artery using Doppler ultrasound, oxygenation of the soleus muscle assessed by near-infrared spectroscopy, lactate concentrations determined in capillary blood and muscle activity using soleus muscle surface electromyography. Furthermore, soleus muscle biopsies were taken to investigate morphological muscle changes. After the intervention, maximal isokinetic torque was reduced by 23·4 ± 8·2% (Pflow, tissue oxygenation, lactate concentrations and EMG median frequency kinematics during the exercise test were comparable before and after the intervention, whereas the increase of RMS in response to IIET was less following the intervention (P = 0·03). In conclusion, following submaximal isokinetic muscle work exercise-induced muscle fatigue is unaffected after prolonged local muscle unloading. The observation that arterial blood flow was maintained may underlie the unchanged fatigability. © 2013 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

  5. Efeito de drogas utilizadas no tratamento de hipertensão arterial sistêmica sobre a pressão intra-ocular: estudo experimental no cão

    Hashimoto Mitsuo

    2002-01-01

    Full Text Available Objetivo: Estudar os efeitos de duas drogas utilizadas no tratamento de hipertensão arterial sistêmica (captopril e propranolol sobre a pressão intra-ocular (PIO e pressão de perfusão (PP em cães anestesiados. Métodos: Foram estudados 24 cães, divididos em 3 grupos de 8. No primeiro grupo (GI, foi administrado captopril (um inibidor da enzima conversora de angiotensina na dose de 1,5 mg/kg por via endovenosa. No segundo grupo (GII, foi administrado propranolol (um beta-bloqueador na dose de 1,5 mg/kg por via endovenosa. O terceiro grupo (GIII foi o grupo controle. A PIO e a pressão arterial média (PAm foram medidas por manometria. A pressão de perfusão (PP foi calculada pela diferença entre a PAm e a PIO. A freqüência cardíaca (FC foi monitorada com oxímetro de pulso. Os parâmetros foram estudados em 6 momentos (0, 10, 30, 60, 90 e 120 minutos. Resultados: Houve redução estatisticamente significativa da PIO (p<0,05 nos grupos em que foram administrados captopril e propranolol, sem diferença entre as drogas. Com captopril, houve redução da PAm e da PP aos 10 e 30 minutos. Com propranolol, não houve redução da PAm ou da PP. Conclusão: Houve redução da PIO com uso do captopril e também do propranolol. Entretanto, a redução acentuada da PAm e da PP causadas pelo captopril, podem ser indesejáveis para a irrigação do nervo óptico.

  6. A pilot study of the relationship between Doppler-estimated carotid and brachial artery flow and cardiac index.

    Weber, U; Glassford, N J; Eastwood, G M; Bellomo, R; Hilton, A K

    2015-10-01

    We measured carotid and brachial artery blood flow by Doppler ultrasound in 11 human volunteers, and related these to cardiac index and to each other. The median (IQR [range]) carotid arterial blood flow was 0.334 (0.223-0.381 [0.052-0.563]) l.min(-1) on the right and 0.315 (0.223-0.369 [0.061-0.690]) l.min(-1) on the left. The brachial arterial blood flow was 0.049 (0.033-0.062 [0.015-0.204]) l.min(-1) on the right and 0.039 (0.027-0.054 [0.011-0.116]) on the left. Cardiac index was 3.2 (2.8-3.5 [1.9-5.4]) l.min(-1) .m(-2) . There was a moderate to good correlation between right-and left-sided flows (brachial: ρ = 0.45; carotid: ρ = 0.567). Brachial and carotid flow had no or a negative correlation with cardiac index (right brachial: ρ = -0.145, left brachial: ρ = -0.349; right carotid: ρ = -0.376, left carotid: ρ = -0.285). In contrast to some previous studies, we found that Doppler-estimated peripheral arterial blood flows only show a weak correlation with cardiac index and cannot be used to provide non-invasive estimates of cardiac index in man. © 2015 The Association of Anaesthetists of Great Britain and Ireland.

  7. Investigation of blood flow rheology using second-grade viscoelastic model (Phan-Thien-Tanner) within carotid artery.

    Ramiar, Abas; Larimi, Morsal Momenti; Ranjbar, Ali Akbar

    2017-01-01

    Hemodynamic factors, such as Wall Shear Stress (WSS), play a substantial role in arterial diseases. In the larger arteries, such as the carotid artery, interaction between the vessel wall and blood flow affects the distribution of hemodynamic factors. The fluid is considered to be non-Newtonian, whose flow is governed by the equation of a second-grade viscoelastic fluid and the effects of viscoelastic on blood flow in carotid artery is investigated. Pulsatile flow studies were carried out in a 3D model of carotid artery. The governing equations were solved using finite volume C++ based on open source code, OpenFOAM. To describe blood flow, conservation of mass and momentum, a constitutive relation of simplified Phan-Thien-Tanner (sPTT), and appropriate relations were used to explain shear thinning behavior. The first recirculation was observed at t = 0.2 s, in deceleration phase. In the acceleration phase from t = 0.3 s to t = 0.5 s, vortex and recirculation sizes in bulb regions in both ECA and ICA gradually increased. As is observed in the line graphs based on extracted data from ICA, at t = 0.2 s, τyy is the maximum amount of wall shear stress and τxy the minimum one. The maximum shear stress occurred in the inner side of the main branch (inner side of ICA and ECA) because the velocity of blood flow in the inner side of the bulb region was maximum due to the created recirculation zone in the opposite side in this area. The rheology of blood flow and shear stress in various important parts (the area that are in higher rates of WSS such as bifurcation region and the regions after bulb areas in both branches, Line1-4 in Fig. 7) were also analyzed. The investigation of velocity stream line, velocity profile and shear stress in various sections of carotid artery showed that the maximum shear stress occurred in acceleration phase and in the bifurcation region between ECA and ICA which is due to velocity gradients and changes in thinning behavior of blood and

  8. Differential increases in blood flow velocity in the middle cerebral artery after tourniquet deflation during sevoflurane, isoflurane or propofol anaesthesia.

    Kadoi, Y; Kawauchi, C H; Ide, M; Saito, S; Mizutani, A

    2009-07-01

    The purpose of this study was to examine the comparative effects of sevoflurane, isoflurane or propofol on cerebral blood flow velocity after tourniquet deflation during orthopaedic surgery. Thirty patients undergoing elective orthopaedic surgery were randomly divided into sevoflurane, isoflurane and propofol groups. Anaesthesia was maintained with sevoflurane, isoflurane or propofol infusion in 33% oxygen and 67% nitrous oxide, in whatever concentrations were necessary to keep bispectral index values between 45 and 50. Ventilatory rate or tidal volume was adjusted to target PaCO2 of 35 mmHg. A 2.0 MHz transcranial Doppler probe was attached to the patient's head at the temporal window and mean blood flow velocity in the middle cerebral artery was continuously measured. The extremity was exsanguinated with an Esmarch bandage and the pneumatic tourniquet was inflated to a pressure of 450 mmHg. Arterial blood pressure, heart rate, velocity in the middle cerebral artery and arterial blood gas analysis were measured every minute for 10 minutes after release of the tourniquet in all three groups. Velocity in the middle cerebral artery in the three groups increased for five minutes after tourniquet deflation. Because of the different cerebrovascular effects of the three agents, the degree of increase in flow velocity in the isoflurane group was greater than in the other two groups, the change in flow velocity in the propofol group being the lowest (at three minutes after deflation 40 +/- 7%, 32 +/- 6% and 28 +/- 10% in the isoflurane, sevoflurane and propofol groups respectively, P < 0.05).

  9. Doppler color flow analysis of the uterine arteries before and after intrauterine device insertion: a prospective study.

    de Souza, Marco Aurélio Martins; Geber, Selmo

    2006-02-01

    An intrauterine device (IUD) is one of the most frequently used methods of birth control around the world. Although a relationship between its use and menstrual disorders has been well documented, only a few studies have tried to show whether there are any vascular modifications. The aim of our study was to evaluate the influence of an IUD on uterine artery blood flow using Doppler assessment. A total of 100 patients selected for IUD use were prospectively evaluated with Doppler analysis before and 30 days after insertion. The resistive index (RI) and pulsatility index (PI) were used to evaluate uterine artery vascular resistance. Patients were allocated in 2 groups according to whether they were (group 2) or were not (group 1) lactating. The PI and RI of the patients in groups 1 and 2 before and after IUD insertion were not statistically significantly different (P = .298 and .23). When we compared uterine artery blood flow indices before and after IUD insertion for groups 1 and 2 separately, we observed in group 1 that the mean +/- SD PI values were 2.45 +/- 0.62 and 2.55 +/- 0.55 (P = .38) and the RI values were 0.87 +/- 0.08 and 0.87 +/- 0.06 (P = .88) before and after IUD insertion, respectively. In group 2, the PI values were 2.31 +/- 0.55 and 2.37 +/- 0.69 (P = .68) and the RI values were 0.85 +/- 0.07 and 0.86 +/- 0.07 (P = .44) before and after IUD insertion. Finally, we used the mean blood flow indices of the uterine arteries of all patients to compare the effect of IUD insertion. Results were also not statistically significant when we compared PI and RI before and after IUD insertion. The presence of an IUD does not interfere with the vascular resistance of the uterine arteries that can be shown by Doppler flow assessments 1 month after insertion.

  10. A case of reocclusion of the renal artery diagnosed by the color Doppler method with evaluation of blood flow direction in the collateral circulation of the kidney in addition to the non-detectable blood signal in the renal artery.

    Hirano, Megumi; Ohta, Tomoyuki; Nakata, Norio; Kawakami, Reina; Takamura, Kimihiro; Matsuda, Tosiharu; Nishioka, Makiko; Sakurai, Tomoo; Matsuo, Kouichi; Miyamoto, Yukio

    2014-10-01

    A 23-year-old woman was referred to our hospital for an interventional procedure for chronic total occlusion of the right renal artery, probably due to fibromuscular dysplasia (FMD), and for control of renal vascular hypertension. Before percutaneous transluminal renal angioplasty (PTRA), aortography revealed collateral circulation to the right kidney from the lower lumbar artery. After PTRA, however, blood flow in the renal side of the collateral circulation flowed outside from the right renal parenchyma. 4 months later, we could not find a blood flow signal in the right renal artery, and there was a contrary flow signal in the right kidney parenchyma continuously from the extrahilar vessel, possibly a collateral artery. These findings indicated reocclusion of the right artery. We confirmed reocclusion of the renal artery and collateral feeding by contrast dynamic computed tomography (CT), and PTRA was performed again without any complications or reocclusion for 5 months. This is the first case report showing that a back-flowing signal in the right renal parenchyma from the extrahilar artery is useful as an indirect finding suggesting reocclusion.

  11. Secondary flow in a curved artery model with Newtonian and non-Newtonian blood-analog fluids

    Najjari, Mohammad Reza; Plesniak, Michael W.

    2016-11-01

    Steady and pulsatile flows of Newtonian and non-Newtonian fluids through a 180°-curved pipe were investigated using particle image velocimetry (PIV). The experiment was inspired by physiological pulsatile flow through large curved arteries, with a carotid artery flow rate imposed. Sodium iodide (NaI) and sodium thiocyanate (NaSCN) were added to the working fluids to match the refractive index (RI) of the test section to eliminate optical distortion. Rheological measurements revealed that adding NaI or NaSCN changes the viscoelastic properties of non-Newtonian solutions and reduces their shear-thinning property. Measured centerline velocity profiles in the upstream straight pipe agreed well with an analytical solution. In the pulsatile case, secondary flow structures, i.e. deformed-Dean, Dean, Wall and Lyne vortices, were observed in various cross sections along the curved pipe. Vortical structures at each cross section were detected using the d2 vortex identification method. Circulation analysis was performed on each vortex separately during the systolic deceleration phase, and showed that vortices split and rejoin. Secondary flow structures in steady flows were found to be morphologically similar to those in pulsatile flows for sufficiently high Dean number. supported by the George Washington University Center for Biomimetics and Bioinspired Engineering.

  12. Flow- and acetylcholine-induced dilation in small arteries from rats with renovascular hypertension - effect of tempol treatment

    Christensen, Frank Holden; Stankevicius, Edgaras; Hansen, Thomas

    2007-01-01

    -treated animals, while only the relaxation was improved by the NO donor, S-nitroso-N-acetylpenicillamine (SNAP). In conclusion renovascular hypertension selectively inhibits flow-induced NO-mediated vasodilatation, while EDHF-type vasodilatation remains unaffected, suggesting that high blood pressure leads...... blood pressure and tempol treatment. Simultaneous measurements of NO-concentration and relaxation were performed in isolated coronary arteries from the same animals. As compared to vehicle-treated rats, both acetylcholine-induced relaxation and NO-concentration increased in arteries from tempol......-induced dilatation remained normal. Measured by dihydroethidium staining there was an increased amount of superoxide in arteries from vehicle-treated rats, but not from tempol-treated rats. Expression by immunoblotting of endothelial NO synthase and the NAD(P)H oxidase subunit p47phox remained unaffected by high...

  13. Estimation of arterial arrival time and cerebral blood flow from QUASAR arterial spin labeling using stable spline.

    Castellaro, Marco; Peruzzo, Denis; Mehndiratta, Amit; Pillonetto, Gianluigi; Petersen, Esben Thade; Golay, Xavier; Chappell, Michael A; Bertoldo, Alessandra

    2015-12-01

    QUASAR arterial spin labeling (ASL) permits the application of deconvolution approaches for the absolute quantification of cerebral perfusion. Currently, oscillation index regularized singular value decomposition (oSVD) combined with edge-detection (ED) is the most commonly used method. Its major drawbacks are nonphysiological oscillations in the impulse response function and underestimation of perfusion. The aim of this work is to introduce a novel method to overcome these limitations. A system identification method, stable spline (SS), was extended to address ASL peculiarities such as the delay in arrival of the arterial blood in the tissue. The proposed framework was compared with oSVD + ED in both simulated and real data. SS was used to investigate the validity of using a voxel-wise tissue T1 value instead of using a single global value (of blood T1 ). SS outperformed oSVD + ED in 79.9% of simulations. When applied to real data, SS exhibited a physiologically realistic range for perfusion and a higher mean value with respect to oSVD + ED (55.5 ± 9.5 SS, 34.9 ± 5.2 oSVD + ED mL/100 g/min). SS can represent an alternative to oSVD + ED for the quantification of QUASAR ASL data. Analysis of the retrieved impulse response function revealed that using a voxel wise tissue T1 might be suboptimal. © 2014 Wiley Periodicals, Inc.

  14. Arterial bending angle and wall morphology correlate with slow coronary flow: Determination with multidetector CT coronary angiography

    Kantarci, Mecit; Guendogdu, Fuat; Doganay, Selim; Duran, Cihan; Kalkan, M. Emin; Sagsoz, M. Erdem; Kucuk, Osman; Karakaya, Afak; Kucuk, Ahmet; Akguen, Metin

    2011-01-01

    Background and purpose: The purpose of this study was to assess angulations and vessel wall morphology that could lead to bending head loss in the RCA and LMCA arteries of patients with slow coronary flow (SCF) evaluated by MDCT coronary angiography. Methods: The study involved 51 patients (45 males, mean age: 59.6 years) who were diagnosed with SCF by coronary angiography. Diagnosis of SCF was based on thrombolysis in myocardial infarction (TIMI) frame count. Fifty-one patients with absence of slow flow were selected as the control group. The angulations of the main coronary arteries with the aorta were measured from the axial images obtained through MDCT coronary angiography, and the findings were recorded. In addition, the coronary artery walls of these patients were evaluated. For statistical analysis, SPSS for Windows 10.0 (SPSS Inc., Chicago, IL) was used. For comparisons of the angles, either independent samples t test or the Mann-Whitney U test was used where appropriate. Results: The results of the study indicated that 38 patients had SCF in the LAD. Comparisons of patients with SCF with the controls revealed that in the patients with SCF, the mean angle of the LMCA with the aorta (40.9 ± 20.5 o ) was statistically significantly smaller than the mean angle of the LMCA with the aorta in the control cases (71.8 ± 11 o ). In 12 patients, slow flow was detected in the RCA. Those with slow flow in the RCA had significantly smaller angles (mean: 33.2 ± 20.4 o ) than the other cases (mean: 78.9 ± 10.7 o ). Conclusion: A small angle of origin of the main coronary arteries from the aorta, measured on MDCT examinations is correlated with slow blood flow in those vessels, as calculated by the TIMI frame count in catheter coronary angiography.

  15. Arterial bending angle and wall morphology correlate with slow coronary flow: Determination with multidetector CT coronary angiography

    Kantarci, Mecit, E-mail: akkanrad@hotmail.com [Department of Radiology, Medical Faculty, Atatuerk University, Erzurum (Turkey); Guendogdu, Fuat [Department of Cardiology, Medical Faculty, Atatuerk University, Erzurum (Turkey); Doganay, Selim [Department of Radiology, Medical Faculty, Erciyes University, Kayseri (Turkey); Duran, Cihan [Department of Radiology, Bilim University, Florence Nightingale Hospital, Istanbul (Turkey); Kalkan, M. Emin [Department of Cardiology, Medical Faculty, Atatuerk University, Erzurum (Turkey); Sagsoz, M. Erdem [Department of Radiology, Medical Faculty, Atatuerk University, Erzurum (Turkey); Kucuk, Osman [Department of Electronic Engineering, Engineering Faculty, Atatuerk University, Erzurum (Turkey); Karakaya, Afak [Department of Radiology, Medical Faculty, Atatuerk University, Erzurum (Turkey); Kucuk, Ahmet [Department of Mathematics, Science Faculty, Atatuerk University, Erzurum (Turkey); Akguen, Metin [Department of Chest, Medical Faculty, Atatuerk University, Erzurum (Turkey)

    2011-01-15

    Background and purpose: The purpose of this study was to assess angulations and vessel wall morphology that could lead to bending head loss in the RCA and LMCA arteries of patients with slow coronary flow (SCF) evaluated by MDCT coronary angiography. Methods: The study involved 51 patients (45 males, mean age: 59.6 years) who were diagnosed with SCF by coronary angiography. Diagnosis of SCF was based on thrombolysis in myocardial infarction (TIMI) frame count. Fifty-one patients with absence of slow flow were selected as the control group. The angulations of the main coronary arteries with the aorta were measured from the axial images obtained through MDCT coronary angiography, and the findings were recorded. In addition, the coronary artery walls of these patients were evaluated. For statistical analysis, SPSS for Windows 10.0 (SPSS Inc., Chicago, IL) was used. For comparisons of the angles, either independent samples t test or the Mann-Whitney U test was used where appropriate. Results: The results of the study indicated that 38 patients had SCF in the LAD. Comparisons of patients with SCF with the controls revealed that in the patients with SCF, the mean angle of the LMCA with the aorta (40.9 {+-} 20.5{sup o}) was statistically significantly smaller than the mean angle of the LMCA with the aorta in the control cases (71.8 {+-} 11{sup o}). In 12 patients, slow flow was detected in the RCA. Those with slow flow in the RCA had significantly smaller angles (mean: 33.2 {+-} 20.4{sup o}) than the other cases (mean: 78.9 {+-} 10.7{sup o}). Conclusion: A small angle of origin of the main coronary arteries from the aorta, measured on MDCT examinations is correlated with slow blood flow in those vessels, as calculated by the TIMI frame count in catheter coronary angiography.

  16. Estimation of the supplementary axial wall stress generated at peak flow by an arterial stenosis

    Doriot, Pierre-Andre

    2003-01-01

    Mechanical stresses in arterial walls are known to be implicated in the development of atherosclerosis. While shear stress and circumferential stress have received a lot of attention, axial stress has not. Yet, stenoses can be intuitively expected to produce a supplementary axial stress during flow systole in the region immediately proximal to the constriction cone. In this paper, a model for the estimation of this effect is presented, and ten numerical examples are computed. These examples show that the cyclic increase in axial stress can be quite considerable in severe stenoses (typically 120% or more of the normal stress value). This result is in best agreement with the known mechanical or morphological risk factors of stenosis progression and restenosis (hypertension, elevated pulse pressure, degree of stenosis, stenosis geometry, residual stenosis, etc). The supplementary axial stress generated by a stenosis might create the damages in the endothelium and in the elastic membranes which potentiate the action of the other risk factors (hyperlipidaemia, diabetes, etc). It could thus be an important cause of stenosis progression and of restenosis

  17. Arterial line pressure control enhanced extracorporeal blood flow prescription in hemodialysis patients

    Rosales Laura

    2008-11-01

    Full Text Available Abstract Background In hemodialysis, extracorporeal blood flow (Qb recommendation is 300–500 mL/min. To achieve the best Qb, we based our prescription on dynamic arterial line pressure (DALP. Methods This prospective study included 72 patients with catheter Group 1 (G1, 1877 treatments and 35 arterio-venous (AV fistulae Group 2 (G2, 1868 treatments. The dialysis staff was trained to prescribe Qb sufficient to obtain DALP between -200 to -250 mmHg. We measured ionic clearance (IK: mL/min, access recirculation, DALP (mmHg and Qb (mL/min. Six prescription zones were identified: from an optimal A zone (Qb > 400, DALP -200 to -250 to zones with lower Qb E (Qb -199. Results Treatments distribution in A was 695 (37% in G1 vs. 704 (37.7% in G2 (P = 0.7. In B 150 (8% in G1 vs. 458 (24.5% in G2 (P P = 0.62. IK in A was 214 ± 34 (G1 vs. 213 ± 35 (G2 (P = 0.65. IK Anova between G2 zones was: A vs. C and D (P P = 0.02. Conclusion In conclusion, an optimal Qb can de prescribed with DALP of -200 mmHg. Staff adherence to DLAP treatment prescription could be reached up to 81.3% in catheters and 84.1% in AV fistulae.

  18. Evaluation of factors influencing arterial Doppler waveforms in an in vitro flow phantom

    Sung, Chang Kyu [Dept. of Radiology, SMG-SNU Boramae Medical Center, Seoul National University College of Medicine, Seoul (Korea, Republic of); Lee, Kyoung Ho [Dept. of Radiology, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam (Korea, Republic of); Kim, Seung Hyup [Dept. of Radiology and the Institute of Radiation Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul (Korea, Republic of)

    2017-01-15

    The aim of this study was to investigate factors that influence arterial Doppler waveforms in an in vitro phantom to provide a more accurate and comprehensive explanation of the Doppler signal. A flow model was created using a pulsatile artificial heart, rubber or polyethylene tubes, a water tank, and a glass tube. Spectral Doppler tracings were obtained in multiple combinations of compliance, resistance, and pulse rate. Peak systolic velocity, minimum diastolic velocity, resistive index (RI), pulsatility index, early systolic acceleration time, and acceleration index were measured. On the basis of these measurements, the influences of the variables on the Doppler waveforms were analyzed. With increasing distal resistance, the RI increased in a relatively linear relationship. With increasing proximal resistance, the RI decreased. The pulsus tardus and parvus phenomenon was observed with a small acceleration index in the model with a higher grade of stenosis. An increase in the distal resistance masked the pulsus tardus and parvus phenomenon by increasing the acceleration index. Although this phenomenon occurred independently of compliance, changes in the compliance of proximal or distal tubes caused significant changes in the Doppler waveform. There was a reverse relationship between the RI and the pulse rate. Resistance and compliance can alter the Doppler waveforms independently. The pulse rate is an extrinsic factor that also influences the RI. The compliance and distal resistance, as well as proximal resistance, influence the pulsus tardus and parvus phenomenon.

  19. Resting state cerebral blood flow with arterial spin labeling MRI in developing human brains.

    Liu, Feng; Duan, Yunsuo; Peterson, Bradley S; Asllani, Iris; Zelaya, Fernando; Lythgoe, David; Kangarlu, Alayar

    2018-07-01

    The development of brain circuits is coupled with changes in neurovascular coupling, which refers to the close relationship between neural activity and cerebral blood flow (CBF). Studying the characteristics of CBF during resting state in developing brain can be a complementary way to understand the functional connectivity of the developing brain. Arterial spin labeling (ASL), as a noninvasive MR technique, is particularly attractive for studying cerebral perfusion in children and even newborns. We have collected pulsed ASL data in resting state for 47 healthy subjects from young children to adolescence (aged from 6 to 20 years old). In addition to studying the developmental change of static CBF maps during resting state, we also analyzed the CBF time series to reveal the dynamic characteristics of CBF in differing age groups. We used the seed-based correlation analysis to examine the temporal relationship of CBF time series between the selected ROIs and other brain regions. We have shown the developmental patterns in both static CBF maps and dynamic characteristics of CBF. While higher CBF of default mode network (DMN) in all age groups supports that DMN is the prominent active network during the resting state, the CBF connectivity patterns of some typical resting state networks show distinct patterns of metabolic activity during the resting state in the developing brains. Copyright © 2018 European Paediatric Neurology Society. All rights reserved.

  20. Redundant Vasodilator Pathways Underlying Radial Artery Flow-Mediated Dilation Are Preserved in Healthy Aging

    Kevin D. Ballard

    2014-01-01

    Full Text Available Background. Blocking nitric oxide (NO and vasodilator prostanoids (PN does not consistently reduce flow-mediated dilation (FMD in young adults. The impact of aging on the contribution of NO and PG to FMD is unknown. Methods. FMD was measured in older adults (n=10, 65±3 y after arterial infusion of saline, N(G-monomethyl-L-arginine (L-NMMA, and ketorolac + L-NMMA. Data were compared to published data in young adults. Results. L-NMMA reduced FMD in older adults (8.9±3.6 to 5.9±3.7% although this was not statistically significant (P=0.08 and did not differ (P=0.74 from the reduction observed in young adults (10.0±3.8 to 7.6±4.7%; P=0.03. Blocking PN did not affect FMD in young or older adults. In older adults, L-NMMA reduced (n=6; range = 36–123% decrease, augmented (n=3; 10–122% increase, or did not change FMD (n=1; 0.4% increase. After PN blockade, FMD responses were reduced (n=2, augmented (n=6, or unaffected (n=1. Conclusions. NO or PN blockade did not consistently reduce FMD in healthy older adults, suggesting the existence of redundant vasodilator phenotypes as observed previously in young adults.

  1. Estimation of the supplementary axial wall stress generated at peak flow by an arterial stenosis

    Doriot, Pierre-André

    2003-01-01

    Mechanical stresses in arterial walls are known to be implicated in the development of atherosclerosis. While shear stress and circumferential stress have received a lot of attention, axial stress has not. Yet, stenoses can be intuitively expected to produce a supplementary axial stress during flow systole in the region immediately proximal to the constriction cone. In this paper, a model for the estimation of this effect is presented, and ten numerical examples are computed. These examples show that the cyclic increase in axial stress can be quite considerable in severe stenoses (typically 120% or more of the normal stress value). This result is in best agreement with the known mechanical or morphological risk factors of stenosis progression and restenosis (hypertension, elevated pulse pressure, degree of stenosis, stenosis geometry, residual stenosis, etc). The supplementary axial stress generated by a stenosis might create the damages in the endothelium and in the elastic membranes which potentiate the action of the other risk factors (hyperlipidaemia, diabetes, etc). It could thus be an important cause of stenosis progression and of restenosis.

  2. Converting to increased Tc-99m DTPA renal flow from slight decrease in renal flow following angioplastic procedures in a patient with unequal renal artery stenoses

    Shih Weijen; Mitchell, B.L.

    1990-01-01

    The use of Tc-99m DTPA renal flow imaging has increased in importance since the introduction of catheter angioplasty. The high diagnostic accuracy and non-invasive technique as compared to digital subtraction angiography have done much to enhance its usage in the evaluation of renal functional status. This paper reports Tc-99m DTPA renal flow imaging findings before and after angioplasty in a patient with bilateral renal artery stenosis. The slight decrease in Tc-99m DTPA renal flow on the kidney before angioplasty converted to an increase in flow on the right kidney after angioplasty. Post procedural blood flow was much higher on the right, where stenosis was previously more severe. It is hypothesized that the right kidney was protected from elevated aterial pressure by its 90% arterial stenosis while the left kidney was exposed to elevated systemic blood pressure. Because of vascular damage to the unprotected left kidney, post-angioplasty blood flow was less in the left kidney than in the ischemic but protected right kidney. (orig.) [de

  3. Measurement of cerebral blood flow by single photon emission computed tomography in cases of internal carotid artery occlusion

    Sunada, Ichiro [Osaka City Univ. (Japan). Faculty of Medicine

    1989-06-01

    Cerebral blood flow (CBF) was measured with {sup 133}xenon inhalation and single photon emission computed tomography in 33 cases of internal carotid artery occlusion, in the resting state and 25 minutes after acetazolamide administration. The patient population consisted of 24 males and nine females with a mean age of 57 years, who presented with transient ischemic attacks or stroke. Acetazolamide inhibits carbonic anhydrase, and CBF increases as a result of dilatation of cerebral arteries due to CO{sub 2} accumulation. The mean CBF was 46 ml/100 g/min on the affected hemisphere and 56 ml/100 g/min on the unaffected hemisphere. The mean CBF value obtained by the same method in 10 normal volunteers was 55 ml/100 g/min. The average increase in CBF after acetazolamide administration was 9% on the affected side and 17% on the unaffected side. The average increase in 10 normal volunteers was 32%. The reduced cerebral arterial reactivity to acetazolamide administration was bilateral in the patient group, suggesting that the cerebral arteries were dilated so as to maintain normal CBF. Extra-intracranial (EC-IC) bypass surgery was performed in nine patients. Preoperatively, the mean CBF was 48 ml/100 g/min on the affected side and 57 ml/100 g/min on the unaffected side. With postoperative acetazolamide administration, the percent increase in CBF rose from 13% to 22% on the affected side and from 17% to 23% on the unaffected side. The bilateral change toward normal in cerebral arterial reactivity to acetazolamide indicates that the dilated cerebral arteries returned to normal after EC-IC bypass surgery. This suggests that bypass surgery is effective in patients with internal carotid artery occlusion in whom ischemia is caused only by hemodynamic factors, and that measurement of CBF via acetazolamide loading is useful in identifying appropriate candidates for bypass surgery.

  4. Accurate perioperative flow measurement of the portal vein and hepatic and renal artery: A role for preoperative MRI?

    Vermeulen, Mechteld A.R., E-mail: mar.vermeulen@vumc.nl [Department of Surgery, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam (Netherlands); Ligthart-Melis, Gerdien C., E-mail: g.ligthart-melis@vumc.nl [Department of Internal Medicine, Dietetics and Nutritional Sciences, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam (Netherlands); Buijsman, René, E-mail: renebuysman@gmail.com [Department of Surgery, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam (Netherlands); Siroen, Michiel P.C., E-mail: m.siroen6@upcmail.nl [Department of Surgery, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam (Netherlands); Poll, Marcel C.G. van de, E-mail: mcg.vandepoll@ah.unimaas.nl [Department of Surgery, Maastricht University Medical Center, P.O. Box 5800, 6202 AZ Maastricht (Netherlands); Boelens, Petra G., E-mail: p.boelens@mumc.nl [Department of Surgery, Maastricht University Medical Center, P.O. Box 5800, 6202 AZ Maastricht (Netherlands); Dejong, Cornelis H.C., E-mail: chc.dejong@mumc.nl [Department of Surgery, Maastricht University Medical Center, P.O. Box 5800, 6202 AZ Maastricht (Netherlands); Schaik, Cors van, E-mail: c.vanschaik@vumc.nl [Department of Radiology, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam (Netherlands); Hofman, Mark B.M., E-mail: mbm.hofman@vumc.nl [Department of Physics and Medical Technology, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam (Netherlands); Leeuwen, Paul A.M. van, E-mail: pam.vleeuwen@vumc.nl [Department of Surgery, VU University Medical Center, P.O. Box 7057, 1007 MB Amsterdam (Netherlands)

    2012-09-15

    Background: Quantification of abdominal blood flow is essential for a variety of gastrointestinal and hepatic topics such as liver transplantation or metabolic flux measurement, but those need to be performed during surgery. It is not clear whether Duplex Doppler Ultrasound during surgery or MRI before surgery is the tool to choose. Objective: To examine whether preoperative evaluation of abdominal blood flow using MRI could prove to be a useful and reliable alternative for the perioperative sonographic approach. Methods: In this study portal and renal venous flow and hepatic arterial flow were sequentially quantified by preoperative MRI, preoperative and perioperative Duplex Doppler Ultrasound (DDUS). 55 Patients scheduled for major abdominal surgery were studied and methods and settings were compared. Additionally, average patient population values were compared. Results: Mean (±SD) plasmaflow measured by perioperative DDUS, preoperative DDUS and MRI, respectively was 433 ± 200/423 ± 162/507 ± 96 ml/min (portal vein); 96 ± 70/74 ± 41/108 ± 91 ml/min (hepatic artery); 248 ± 139/201 ± 118/219 ± 69 ml/min (renal vein). No differences between the different settings of DDUS measurement were detected. Equality of mean was observed for all measurements. Bland Altman Plots showed widespread margins. Hepatic arterial flow measurements correlated with each other, but portal and renal venous flow correlations were absent. Conclusions: Surgery and method (DDUS vs. MRI) do not affect mean flow values. Individual comparison is restricted due to wide range in measurements. Since MRI proves to be more reliable with respect to inter-observer variability, we recommend using mean MRI results in experimental setups.

  5. Prognostic value of renal fractional flow reserve in blood pressure response after renal artery stenting (PREFER study).

    Kądziela, Jacek; Januszewicz, Andrzej; Prejbisz, Aleksander; Michałowska, Ilona; Januszewicz, Magdalena; Florczak, Elżbieta; Kalińczuk, Łukasz; Norwa-Otto, Bożena; Warchoł, Ewa; Witkowski, Adam

    2013-01-01

    The aim of our study was to determine a potential relationship between resting translesional pressures ratio (Pd/Pa ratio), renal fractional flow reserve (rFFR) and blood pressure response after renal artery stenting. Thirty five hypertensive patients (49% males, mean age 64 years) with at least 60% stenosis in angiography, underwent renal artery stenting. Translesional systolic pressure gradient (TSPG), Pd/Pa ratio (the ratio of mean distal to lesion and mean proximal pressures) and hyperemic rFFR - after intrarenal administration of papaverine - were measured before stent implantation. Ambulatory blood pressure measurements (ABPM) were recorded before the procedure and after 6 months. The ABPM results were presented as blood pressure changes in subgroups of patients with normal (≥ 0.9) vs. abnormal (renal artery stenting. Median changes of 24-h systolic/diastolic blood pressure were comparable in patients with abnormal vs. normal Pd/Pa ratio (-4/-3 vs. 0/2 mm Hg; p = NS) and with abnormal vs. normal rFFR (-2/-1 vs. -2/-0.5 mm Hg, respectively). Physiological assessment of renal artery stenosis using Pd/Pa ratio and papaverine- induced renal fractional fl ow reserve did not predict hypertension response after renal artery stenting.

  6. Modeling and analysis of biomagnetic blood Carreau fluid flow through a stenosis artery with magnetic heat transfer: A transient study.

    Abdollahzadeh Jamalabadi, Mohammad Yaghoub; Daqiqshirazi, Mohammadreza; Nasiri, Hossein; Safaei, Mohammad Reza; Nguyen, Truong Khang

    2018-01-01

    We present a numerical investigation of tapered arteries that addresses the transient simulation of non-Newtonian bio-magnetic fluid dynamics (BFD) of blood through a stenosis artery in the presence of a transverse magnetic field. The current model is consistent with ferro-hydrodynamic (FHD) and magneto-hydrodynamic (MHD) principles. In the present work, blood in small arteries is analyzed using the Carreau-Yasuda model. The arterial wall is assumed to be fixed with cosine geometry for the stenosis. A parametric study was conducted to reveal the effects of the stenosis intensity and the Hartman number on a wide range of flow parameters, such as the flow velocity, temperature, and wall shear stress. Current findings are in a good agreement with recent findings in previous research studies. The results show that wall temperature control can keep the blood in its ideal blood temperature range (below 40°C) and that a severe pressure drop occurs for blockages of more than 60 percent. Additionally, with an increase in the Ha number, a velocity drop in the blood vessel is experienced.

  7. Evaluation of the Effects of Sildenafil Citrate (Viagra) on Vertebral Artery Blood Flow in Patients with Vertebro-Basilar Insufficiency

    Bozgeyik, Zulkif; Berilgen, Sait; Ozdemir, Huseyin; Ogur, Erkin; Tekatas, Aslan

    2008-01-01

    To investigate the effects of sildenafil citrate (Viagra) on the vertebral artery blood flow of patients with vertebro-basilar insufficiency (VBI) using color duplex sonography (CDS). The study included 21 patients with VBI (aged 31-76; mean 61.0 ± 10.5 yrs). We administered a 50 mg oral dose of sildenafil citrate to all patients. Next, we measured the peak systolic velocity (Vmax), end diastolic velocity (Vmin), resistive index (RI), pulsatility index (PI), diameter, area, and flow volume (FV) of vertebral arteries using CDS before the administration of sildenafil citrate; 45 minutes after, and 75 minutes after administration. Statistical testing was performed using SPSS for windows version 11.0. The statistical test used to determine the outcome of the analysis was the repeated measures analysis of variance (ANOVA) test. Compared to the baseline values, the vertebral artery diameter, area, and FV increased significantly following the administration of sildenafil citrate. The diameter, area and FV increased from 3.39 mm at 45 minutes to 3.64 mm at 75 minutes, 9.43 cm 2 to 10.80 cm 2 at 45 minutes and 10.81 cm 2 at 75 minutes, as well as from 0.07 L/min at baseline to 0.09 L/min at 45 minutes and unchanged at 75 minutes, respectively. Sildenafil citrate elicited a significant effect on vertebral artery diameter, area and FVs

  8. Evaluation of the effects of sildenafil citrate (viagra) on vertebral artery blood flow in patients with vertebro-basilar insufficiency.

    Bozgeyik, Zulkif; Berilgen, Sait; Ozdemir, Huseyin; Tekatas, Aslan; Ogur, Erkin

    2008-01-01

    To investigate the effects of sildenafil citrate (Viagra) on the vertebral artery blood flow of patients with vertebro-basilar insufficiency (VBI) using color duplex sonography (CDS). The study included 21 patients with VBI (aged 31-76; mean 61.0 +/- 10.5 yrs). We administered a 50 mg oral dose of sildenafil citrate to all patients. Next, we measured the peak systolic velocity (Vmax), end diastolic velocity (Vmin), resistive index (RI), pulsatility index (PI), diameter, area, and flow volume (FV) of vertebral arteries using CDS before the administration of sildenafil citrate; 45 minutes after, and 75 minutes after administration. Statistical testing was performed using SPSS for windows version 11.0. The statistical test used to determine the outcome of the analysis was the repeated measures analysis of variance (ANOVA) test. Compared to the baseline values, the vertebral artery diameter, area, and FV increased significantly following the administration of sildenafil citrate. The diameter, area and FV increased from 3.39 mm at 45 minutes to 3.64 mm at 75 minutes, 9.43 cm(2) to 10.80 cm(2) at 45 minutes and 10.81 cm(2) at 75 minutes, as well as from 0.07 L/min at baseline to 0.09 L/min at 45 minutes and unchanged at 75 minutes, respectively. Sildenafil citrate elicited a significant effect on vertebral artery diameter, area and FVs.

  9. Evaluation of the Effects of Sildenafil Citrate (Viagra) on Vertebral Artery Blood Flow in Patients with Vertebro-Basilar Insufficiency

    Bozgeyik, Zulkif; Berilgen, Sait; Ozdemir, Huseyin; Ogur, Erkin [Firat University School of Medicine, Elazig(Turkmenistan); Tekatas, Aslan [Elazig Government Hospital, Elazig (Turkmenistan)

    2008-12-15

    To investigate the effects of sildenafil citrate (Viagra) on the vertebral artery blood flow of patients with vertebro-basilar insufficiency (VBI) using color duplex sonography (CDS). The study included 21 patients with VBI (aged 31-76; mean 61.0 +- 10.5 yrs). We administered a 50 mg oral dose of sildenafil citrate to all patients. Next, we measured the peak systolic velocity (Vmax), end diastolic velocity (Vmin), resistive index (RI), pulsatility index (PI), diameter, area, and flow volume (FV) of vertebral arteries using CDS before the administration of sildenafil citrate; 45 minutes after, and 75 minutes after administration. Statistical testing was performed using SPSS for windows version 11.0. The statistical test used to determine the outcome of the analysis was the repeated measures analysis of variance (ANOVA) test. Compared to the baseline values, the vertebral artery diameter, area, and FV increased significantly following the administration of sildenafil citrate. The diameter, area and FV increased from 3.39 mm at 45 minutes to 3.64 mm at 75 minutes, 9.43 cm{sup 2} to 10.80 cm{sup 2} at 45 minutes and 10.81 cm{sup 2} at 75 minutes, as well as from 0.07 L/min at baseline to 0.09 L/min at 45 minutes and unchanged at 75 minutes, respectively. Sildenafil citrate elicited a significant effect on vertebral artery diameter, area and FVs

  10. Changes in distribution of hepatic blood flow induced by intra-arterial infusion of angiotensin II in human hepatic cancer

    Sasaki, Y.; Imaoka, S.; Hasegawa, Y.

    1985-01-01

    Changes in the distribution of the hepatic blood flow induced by intra-arterial infusion of angiotensin II (AT-II) were studied in human hepatic cancers using extremely short-lived radioisotope (RI) (krypton 81 m [/sup 81m/Kr]; half-life, 13 seconds). After the start of continuous infusion of AT-II, the radioactivity of the tumor showed about a two-fold increase, whereas that of the nontumor region decreased to about one half as much as the level before the infusion. Consequently, the mean ratio of the arterial blood flow in the tumor region to that in the nontumor region (T/N ratio) increased to 3.30 (P less than 0.001). The T/N ratio showed a peak before the peripheral blood pressure reached the maximum, and thereafter tended to decrease. Intra-arterial infusion of AT-II raised the T/N ratio more obviously than did intravenous infusion of the drug, with less rise in the peripheral blood pressure. It is believed that intra-arterial infusion chemotherapy with local use of AT-II enables better accessibility of chemotherapeutic drugs to tumors

  11. An efficient semi-implicit method for three-dimensional non-hydrostatic flows in compliant arterial vessels.

    Fambri, Francesco; Dumbser, Michael; Casulli, Vincenzo

    2014-11-01

    Blood flow in arterial systems can be described by the three-dimensional Navier-Stokes equations within a time-dependent spatial domain that accounts for the elasticity of the arterial walls. In this article, blood is treated as an incompressible Newtonian fluid that flows through compliant vessels of general cross section. A three-dimensional semi-implicit finite difference and finite volume model is derived so that numerical stability is obtained at a low computational cost on a staggered grid. The key idea of the method consists in a splitting of the pressure into a hydrostatic and a non-hydrostatic part, where first a small quasi-one-dimensional nonlinear system is solved for the hydrostatic pressure and only in a second step the fully three-dimensional non-hydrostatic pressure is computed from a three-dimensional nonlinear system as a correction to the hydrostatic one. The resulting algorithm is robust, efficient, locally and globally mass conservative, and applies to hydrostatic and non-hydrostatic flows in one, two and three space dimensions. These features are illustrated on nontrivial test cases for flows in tubes with circular or elliptical cross section where the exact analytical solution is known. Test cases of steady and pulsatile flows in uniformly curved rigid and elastic tubes are presented. Wherever possible, axial velocity development and secondary flows are shown and compared with previously published results. Copyright © 2014 John Wiley & Sons, Ltd.

  12. 3D flow study in a mildly stenotic coronary artery phantom using a whole volume PIV method.

    Brunette, J; Mongrain, R; Laurier, J; Galaz, R; Tardif, J C

    2008-11-01

    Blood flow dynamics has an important role in atherosclerosis initiation, progression, plaque rupture and thrombosis eventually causing myocardial infarction. In particular, shear stress is involved in platelet activation, endothelium function and secondary flows have been proposed as possible variables in plaque erosion. In order to investigate these three-dimensional flow characteristics in the context of a mild stenotic coronary artery, a whole volume PIV method has been developed and applied to a scaled-up transparent phantom. Experimental three-dimensional velocity data was processed to estimate the 3D shear stress distributions and secondary flows within the flow volume. The results show that shear stress reaches values out of the normal and atheroprotective range at an early stage of the obstructive pathology and that important secondary flows are also initiated at an early stage of the disease. The results also support the concept of a vena contracta associated with the jet in the context of a coronary artery stenosis with the consequence of higher shear stresses in the post-stenotic region in the blood domain than at the vascular wall.

  13. Quantitative analysis of arterial flow properties for detection of non-calcified plaques in ECG-gated coronary CT angiography

    Wei, Jun; Zhou, Chuan; Chan, Heang-Ping; Chughtai, Aamer; Agarwal, Prachi; Kuriakose, Jean; Hadjiiski, Lubomir; Patel, Smita; Kazerooni, Ella

    2015-03-01

    We are developing a computer-aided detection system to assist radiologists in detection of non-calcified plaques (NCPs) in coronary CT angiograms (cCTA). In this study, we performed quantitative analysis of arterial flow properties in each vessel branch and extracted flow information to differentiate the presence and absence of stenosis in a vessel segment. Under rest conditions, blood flow in a single vessel branch was assumed to follow Poiseuille's law. For a uniform pressure distribution, two quantitative flow features, the normalized arterial compliance per unit length (Cu) and the normalized volumetric flow (Q) along the vessel centerline, were calculated based on the parabolic Poiseuille solution. The flow features were evaluated for a two-class classification task to differentiate NCP candidates obtained by prescreening as true NCPs and false positives (FPs) in cCTA. For evaluation, a data set of 83 cCTA scans was retrospectively collected from 83 patient files with IRB approval. A total of 118 NCPs were identified by experienced cardiothoracic radiologists. The correlation between the two flow features was 0.32. The discriminatory ability of the flow features evaluated as the area under the ROC curve (AUC) was 0.65 for Cu and 0.63 for Q in comparison with AUCs of 0.56-0.69 from our previous luminal features. With stepwise LDA feature selection, volumetric flow (Q) was selected in addition to three other luminal features. With FROC analysis, the test results indicated a reduction of the FP rates to 3.14, 1.98, and 1.32 FPs/scan at sensitivities of 90%, 80%, and 70%, respectively. The study indicated that quantitative blood flow analysis has the potential to provide useful features for the detection of NCPs in cCTA.

  14. Regional cerebral blod flow studied by xenon-133. Intra-arterial injection studies and inhalation studies using emission tomography

    Lassen, N A

    1980-01-01

    .) technique is insensitive both to hyperemia and ischemia yielding essentially only a mean flow value. A new rapidly moving single photon tomograph following D. Kuhl's principle is presented applicable to Xe-133. Preliminary clinical data show that this technique is able to detect ischemic areas both with Xe......A survey of the Xenon-133 techniques for measurement of regional cerebral blood flow, rCBF, in man is presented. The intra-arterial Xe-133 injection method is very sensitive for detecting even small hyperemic areas, but cannot "see" smaller ischemic areas. The Xe-133 inhalation (or i.v. inj......-133 intra-arterial injection and with Xe-133 inhalation. The practical and economic advantages of Xe-133 or Xe-127 tomography over positron tomography for rCBF are discussed....

  15. Variable-viscosity thermal hemodynamic slip flow conveying nanoparticles through a permeable-walled composite stenosed artery

    Akbar, Noreen Sher; Tripathi, Dharmendra; Bég, O. Anwar

    2017-07-01

    This paper presents a mathematical model for simulating viscous, incompressible, steady-state blood flow containing copper nanoparticles and coupled heat transfer through a composite stenosed artery with permeable walls. Wall slip hydrodynamic and also thermal buoyancy effects are included. The artery is simulated as an isotropic elastic tube, following Joshi et al. (2009), and a variable viscosity formulation is employed for the flowing blood. The equations governing the transport phenomena are non-dimensionalized and the resulting boundary value problem is solved analytically in the steady state subject to physically appropriate boundary conditions. Numerical computations are conducted to quantify the effects of relevant hemodynamic, thermophysical and nanoscale parameters emerging in the model on velocity and temperature profiles, wall shear stress, impedance resistance and also streamline distributions. The model may be applicable to drug fate transport modeling with nanoparticle agents and also to the optimized design of nanoscale medical devices for diagnosing stenotic diseases in circulatory systems.

  16. Coronary Flow Reserve Predicts Cardiopulmonary Fitness in Patients with Coronary Artery Disease Independently of Systolic and Diastolic Function

    Snoer, Martin; Olsen, Rasmus Huan; Monk-Hansen, Tea

    2014-01-01

    Aims Despite revascularization and optimal medical treatment, patients with coronary artery disease (CAD) have reduced exercise capacity. In the absence of coronary artery stenosis, coronary flow reserve (CFR) is a measure of coronary microvascular function, and a marker of future poor outcome...... in CAD patients. The aim of this study was to examine the relationship among CFR, systolic and diastolic function, peripheral vascular function, and cardiopulmonary fitness in CAD patients. Methods and Results Forty patients with median left ventricular ejection fraction (LVEF) 49 (interquartile 46....... Conclusions Coronary flow reserve measured noninvasively predicts cardiopulmonary fitness independently of resting systolic and diastolic function in CAD patients, indicating that cardiac output during maximal exercise is dependent on the ability of the coronary circulation to adapt to the higher metabolic...

  17. Surgical dissection of the internal carotid artery under flow control by proximal vessel clamping reduces embolic infarcts during carotid endarterectomy.

    Yoshida, Kazumichi; Kurosaki, Yoshitaka; Funaki, Takeshi; Kikuchi, Takayuki; Ishii, Akira; Takahashi, Jun C; Takagi, Yasushi; Yamagata, Sen; Miyamoto, Susumu

    2014-01-01

    To evaluate the efficacy of flow control of the internal carotid artery (ICA) by the clamping of the common carotid artery, external carotid artery, and superior thyroid artery during surgical ICA dissection to reduce ischemic complications after carotid endarterectomy (CEA). Sixty-seven patients (59 men; age, 70.5 ± 6.2 years) who underwent CEA by the same surgeon were retrospectively studied. Both conventional CEA (n = 29) and flow-control CEA (n = 38) were performed with the patient under general anesthesia and with the use of somatosensory-evoked potential and near-infrared spectroscopy monitoring as a guide for selective shunting. The number of new postoperative infarcts was assessed with preoperative and postoperative diffusion-weighted images (DWIs) obtained within 3 days of surgery. In addition to surgical technique, the effects of the following factors on new infarcts also were examined: age, side of ICA stenosis, high-grade stenosis, symptoms, and application of shunting. New postoperative DWI lesions were observed in 7 of 67 patients (10.4%), and none of them was symptomatic. With respect to operative technique, the incidence rate of DWI spots was significantly lower in the flow-control group (2.6%) than in the conventional group (20.7%), odds ratio: 0.069; 95% confidence interval: 0.006-0.779; P = 0.031). On multiple logistic regression analysis, age, side of ICA stenosis, high-grade stenosis, symptoms, and the use of internal shunting did not have significant effects on new postoperative DWI lesions, whereas technique did have an effect. The proximal flow-control technique for CEA helps avoid embolic complications during surgical ICA dissection. Copyright © 2014 Elsevier Inc. All rights reserved.

  18. Flow-Through Free Fibula Osteocutaneous Flap in Reconstruction of Tibial Bone, Soft Tissue, and Main Artery Segmental Defects.

    Li, Zonghuan; Yu, Aixi; Qi, Baiwen; Pan, Zhenyu; Ding, Junhui

    2017-08-01

    The aim of this report was to present the use of flow-through free fibula osteocutaneous flap for the repair of complex tibial bone, soft tissue, and main artery segmental defects. Five patients with bone, soft tissue, and segmental anterior tibial artery defects were included. The lengths of injured tibial bones ranged from 4 to 7 cm. The sizes of impaired soft tissues were between 9 × 4 and 15 × 6 cm. The lengths of defect of anterior tibial artery segments ranged from 6 to 10 cm. Two patients had distal limb perfusion problems. Flow-through free fibula osteocutaneous flap was performed for all 5 patients. Patients were followed for 12 to 18 months. All wounds healed after 1-stage operation, and all flow-through flaps survived. The distal perfusion after vascular repair was normal in all patients. Superficial necrosis of flap edge was noted in 1 case. After the local debridement and partial thickness skin graft, the flap healed uneventfully, and the surgical operation did not increase injury to the donor site. Satisfactory bone union was achieved in all patients in 2 to 4 months postoperation. Enlargement of fibula graft was observed during follow-up from 12 to 18 months. The functions of adjacent joints were recovered, and all patients were able to walk normally. Flow-through free fibula osteocutaneous flap was shown to be an effective and efficient technique for repairing composite tibial bone, soft tissue, and main artery segmental defects. This 1-stage operation should be useful in clinical practice for the treatment of complex bone, soft tissue, and vessel defects.

  19. Usefulness of Flow Cytometry in Diagnosis of IgG4-Related Ophthalmic Disease and Extranodal Marginal Zone B-Cell Lymphoma of the Ocular Adnexa.

    Kase, Satoru; Ishijima, Kan; Uraki, Takehiko; Suimon, Yuka; Suzuki, Yasuo; Kase, Manabu; Ishida, Susumu

    2017-09-01

    Although flow cytometry (FCM) is used to evaluate cell surface markers of various leucocyte populations quantitatively, little is known about the usefulness of FCM in lymphoproliferative disorders of the ocular adnexa. The aim of this study was to disclose results of FCM, which were compared among IgG4-related ophthalmic disease (IgG4-ROD), idiopathic orbital inflammation (IOI), and extranodal marginal zone B-cell lymphoma (EMZL). This is a retrospective observational study. Sixty-nine tumors comprising of 16 IgG4-ROD, 24 IOI, and 29 EMZL were enrolled in the study. All tumors, surgically excised, were diagnosed based on histopathology, immunoglobulin (Ig) heavy chain gene rearrangement, and FCM. In FCM, the percentage of T-cell markers (CD2, CD3, CD4, CD5, CD7, CD8), B-cell markers (CD10, CD19, CD20, CD23), NK cell marker (CD56) and cell surface kappa/lambda was searched based on medical records. Ig light chain restriction was evaluated from results in kappa/lambda deviation by FCM. The percentage of CD2, CD3, CD4, CD7, and CD10 was significantly higher in IgG4-ROD/IOI than EMZL (pIgG4-ROD/IOI (pIgG4-ROD and IOI. Kappa-positive cells were significantly greater in EMZL than IgG4-ROD/IOI (pIgG4-ROD/IOI and false-negative was observed in 10 (34.5%) EMZL cases. Sensitivity and specificity of Ig light chain restriction were 65.5 and 92.5%, respectively. Analyses of cell surface markers using FCM were useful in differentiating EMZL from IgG4-ROD/IOI. Sensitivity of Ig light chain restriction was relatively low in diagnosis of EMZL using FCM. Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

  20. Estimating the arterial input function from dynamic contrast-enhanced MRI data with compensation for flow enhancement (I): Theory, method, and phantom experiments

    van Schie, Jeroen J. N.; Lavini, Cristina; van Vliet, Lucas J.; Vos, Frans M.

    2017-01-01

    The arterial input function (AIF) represents the time-dependent arterial contrast agent (CA) concentration that is used in pharmacokinetic modeling. To develop a novel method for estimating the AIF from dynamic contrast-enhanced (DCE-) MRI data, while compensating for flow enhancement. Signal

  1. Correlation of experimental rCBF determinations in goats with flow measurements from a Doppler-modified carotid artery shunt

    Loftus, C.M.; Silvidi, J.A.; Becker, J.A.; Miller, B.V.; Bernstein, D.D.

    1989-01-01

    A carotid artery shunt system has been developed that continuously monitors blood flow rates by embedding a Doppler crystal in the shunt wall. The crystal ranges through a liquid lens that enables it to be placed without violation of the shunt lumen. Because the crystal is at a fixed angle (45 degrees) to the axis of blood flow and the diameter of the lumen remains constant, a linear relationship exists between flow rates and the Doppler velocity signal. This shunt system was previously tested in vitro using a pulsatile pump and was found to be accurate to within 4.7% of the actual flow rate. In the present study, animal (goat) experiments were performed consisting of simultaneous carotid shunt flow and bilateral rCBF measurements by the radiolabeled microsphere technique to determine in vivo the accuracy of this Doppler modified shunt and to ascertain the ability of shunt flow to increase in the face of acute contralateral carotid occlusion. Data from five animals show that in vivo shunt flow can be recorded to within 13% of control rCBF and that shunt flow increases nearly 50% under conditions of distal demand (contralateral carotid occlusion). This device may prove useful in laboratory studies of carotid shunt dynamics and in clinical practice to quickly detect correctable shunt flow abnormalities

  2. Analysis of serial coronary artery flow patterns early after primary angioplasty: new insights into the dynamics of the microcirculation.

    Sharif, Dawod; Rofe, Guy; Sharif-Rasslan, Amal; Goldhammer, Ehud; Makhoul, Nabeel; Shefer, Arie; Hassan, Amin; Rauchfleisch, Shmuel; Rosenschein, Uri

    2008-06-01

    The temporal behavior of the coronary microcirculation in acute myocardial infarction may affect outcome. Diastolic deceleration time and early systolic flow reversal derived from coronary artery blood flow velocity patterns reflect microcirculatory function. To assess left anterior descending coronary artery flow velocity patterns using Doppler transthoracic echocardiography after primary percutaneous coronary intervention, in patients with anterior AMI. Patterns of flow velocity patterns of the LAD were obtained using transthoracic echocardiography-Doppler in 31 consecutive patients who presented with anterior AMI. Measurements were done at 6 hours, 36-48 hours, and 5 days after successful PPCI. Measurements of DDT and pressure half times (Pt%), as well as observation for ESFR were performed. In the first 2 days following PPCI, the average DDT (600 +/- 340 msec) was shorter than on day 5 (807 +/- 332 msec) (P 600 msec) and vice versa. On day 5 most DDTs became longer. Pt1/2 at 6 hours was not different than at day 2 (174 +/- 96 vs. 193 +/- 99 msec, P = NS) and became longer on day 5 (235 +/- 98 msec, P = 0.012). Bidirectional patterns were also observed in the ESFR in 6 patients (19%) at baseline, in 4 (13%) at 36 hours, and in 2 (6.5%) on day 5 after PPCI. Flow velocity patterns of the LAD after PPCI in AMI are dynamic and reflect unpredictable changes in microcirculation.

  3. Modelling and simulation of temperature and concentration dispersion in a couple stress nanofluid flow through stenotic tapered arteries

    Ramana Reddy, J. V.; Srikanth, D.; Das, Samir K.

    2017-08-01

    A couple stress fluid model with the suspension of silver nanoparticles is proposed in order to investigate theoretically the natural convection of temperature and concentration. In particular, the flow is considered in an artery with an obstruction wherein the rheology of blood is taken as a couple stress fluid. The effects of the permeability of the stenosis and the treatment procedure involving a catheter are also considered in the model. The obtained non-linear momentum, temperature and concentration equations are solved using the homotopy perturbation method. Nanoparticles and the two viscosities of the couple stress fluid seem to play a significant role in the flow regime. The pressure drop, flow rate, resistance to the fluid flow and shear stress are computed and their effects are analyzed with respect to various fluids and geometric parameters. Convergence of the temperature and its dependency on the degree of deformation is effectively depicted. It is observed that the Nusselt number increases as the volume fraction increases. Hence magnification of molecular thermal dispersion can be achieved by increasing the nanoparticle concentration. It is also observed that concentration dispersion is greater for severe stenosis and it is maximum at the first extrema. The secondary flow of the axial velocity in the stenotic region is observed and is asymmetric in the tapered artery. The obtained results can be utilized in understanding the increase in heat transfer and enhancement of mass dispersion, which could be used for drug delivery in the treatment of stenotic conditions.

  4. Relationship between interatrial communication, ductus arteriosus, and pulmonary flow patterns in fetuses with transposition of the great arteries: prediction of neonatal desaturation.

    Vaujois, Laurence; Boucoiran, Isabelle; Preuss, Christophe; Brassard, Myriam; Houde, Christine; Fouron, Jean C; Raboisson, Marie-Josée

    2017-09-01

    The relationship between interatrial communication, ductus arteriosus, and pulmonary flow in transposition of the great arteries and intact ventricular septum may help predict postnatal desaturation. Echocardiographic data of 45 fetuses with transposition of the great arteries and intact ventricular septum and 50 age-matched controls were retrospectively reviewed. Interatrial communication, left and right ventricular output, flow in the ductus arteriosus, as well as effective pulmonary flow were measured. Patients were divided into two groups on the basis of postnatal saturations: group 1 had saturations ⩽50% and group 2 >50%. Of 45 fetuses, 13 (26.7%) were classified into group 1. Compared with fetuses in group 2, they had a smaller interatrial communication (2.9 versus 4.0 mm, p=0.004) and more retrograde diastolic flow in the ductus arteriosus (92 versus 23%, p=0.002). Both groups showed a significant decrease in ductal flow compared with controls. Patients in group 2 had a higher effective pulmonary flow compared with controls. There was a mild correlation between left ventricular output and size of the interatrial communication (Spearman's rank correlation 0.44). A retrograde diastolic flow is present in most of the fetuses with postnatal desaturation. Fetuses with transposition of the great arteries have a lower flow through the ductus arteriosus compared with controls. Fetuses without restrictive foramen ovale have higher effective pulmonary flow. Peripheral pulmonary vasodilatation due to higher oxygen saturation in pulmonary arteries in the case of transposition of the great arteries could be one possible cause.

  5. Peripheral Endothelial Function and Coronary Flow Velocity Reserve Are Not Associated in Women with Angina and No Obstructive Coronary Artery Disease

    Flintholm Raft, Kristoffer; Frestad, Daria; Michelsen, Marie Mide

    2017-01-01

    PURPOSE: We investigated whether impaired flow-mediated dilation (FMD) and plasma biomarkers reflecting endothelial dysfunction are associated with coronary microvascular dysfunction (CMD) in women with angina and no obstructive coronary artery disease (CAD). METHODS: Patients (n = 194) were rand...

  6. Transesophageal Doppler measurement of renal arterial blood flow velocities and indices in children.

    Zabala, Luis; Ullah, Sana; Pierce, Carol D'Ann; Gautam, Nischal K; Schmitz, Michael L; Sachdeva, Ritu; Craychee, Judith A; Harrison, Dale; Killebrew, Pamela; Bornemeier, Renee A; Prodhan, Parthak

    2012-06-01

    Doppler-derived renal blood flow indices have been used to assess renal pathologies. However, transesophageal ultrasonography (TEE) has not been previously used to assess these renal variables in pediatric patients. In this study, we (a) assessed whether TEE allows adequate visualization of the renal parenchyma and renal artery, and (b) evaluated the concordance of TEE Doppler-derived renal blood flow measurements/indices compared with a standard transabdominal renal ultrasound (TAU) in children. This prospective cohort study enrolled 28 healthy children between the ages of 1 and 17 years without known renal dysfunction who were undergoing atrial septal defect device closure in the cardiac catheterization laboratory. TEE was used to obtain Doppler renal artery blood velocities (peak systolic velocity, end-diastolic velocity, mean diastolic velocity, resistive index, and pulsatility index), and these values were compared with measurements obtained by TAU. Concordance correlation coefficient (CCC) was used to determine clinically significant agreement between the 2 methods. The Bland-Altman plots were used to determine whether these 2 methods agree sufficiently to be used interchangeably. Statistical significance was accepted at P ≤ 0.05. Obtaining 2-dimensional images of kidney parenchyma and Doppler-derived measurements using TEE in children is feasible. There was statistically significant agreement between the 2 methods for all measurements. The CCC between the 2 imaging techniques was 0.91 for the pulsatility index and 0.66 for the resistive index. These coefficients were sensitive to outliers. When the highest and lowest data points were removed from the analysis, the CCC between the 2 imaging techniques was 0.62 for the pulsatility index and 0.50 for the resistive index. The 95% confidence interval (CI) for pulsatility index was 0.35 to 0.98 and for resistive index was 0.21 to 0.89. The Bland-Altman plots indicate good agreement between the 2 methods; for the

  7. Gradient changes in porcine renal arterial vascular anatomy and blood flow after cryoablation.

    Lagerveld, Brunolf W; van Horssen, Pepijn; Laguna, M Pilar; van den Wijngaard, Jeroen P H M; Siebes, Maria; Wijkstra, Hessel; de la Rosette, Jean J M C H; Spaan, Jos A E

    2011-08-01

    We quantified temporal changes in vascular structure and blood flow after cryosurgery of the porcine kidney in vivo. We studied 5 groups of 4 kidneys each with a survival time of 20 minutes, 4 hours, 2 days, and 1 and 2 weeks after cryoablation, respectively. Before harvesting the kidneys, fluorescently labeled microspheres were administrated in the descending aorta. After harvest the kidney and its vasculature were casted with fluorescently dyed elastomer, frozen and processed in an imaging cryomicrotome to reveal the 3-dimensional arterial branching structure and microsphere distribution. In regions of interest vessels were segmented by image analysis software and histograms were constructed to reveal the total summed vessel length as a function of diameter. A characteristic diameter of the ablated area was measured. The 20-minute survival group histograms showed a significant shift of the peak to larger diameters (p<0.002), indicating that smaller vessels were destroyed. Microsphere density was decreased to 2% in the ablated region but not in the nonablated border zone, depending on the remaining crater crossing larger vessels. After 2 weeks neither vessels nor microspheres were left in the ablated area, which had shrunk by about 40% in diameter. Study limitations are the lack of histological confirmation and the use of normal rather than cancerous tissue. Larger vessels remain patent just after ablation and transport blood to the border of the ablation crater but perfusion within the crater is halted instantly. Characteristic crater diameter increases initially but decreases thereafter. Destruction of vessels and tissue is complete 2 weeks after cryoablation. Copyright © 2011 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

  8. Interventional Exclusion of Iliac Artery Aneurysms Using the Flow-Diverting Multilayer Stent

    Pieper, Claus Christian, E-mail: Claus.christian.pieper@ukb.uni-bonn.de; Meyer, Carsten, E-mail: Carsten.Meyer@ukb.uni-bonn.de [University of Bonn, Department of Radiology (Germany); Rudolph, Jens, E-mail: jens.rudolph@ukb.uni-bonn.de; Verrel, Frauke, E-mail: frauke.verrel@ukb.uni-bonn.de [University of Bonn, Department of Surgery (Germany); Schild, Hans Heinz, E-mail: hans.schild@ukb.uni-bonn.de; Wilhelm, Kai E., E-mail: kai.wilhelm@ukb.uni-bonn.de [University of Bonn, Department of Radiology (Germany)

    2013-08-01

    PurposeThis study was designed to evaluate retrospectively the results of complex iliac artery aneurysm (IAA) exclusion using the Cardiatis-Multilayer-Stent.MethodsBetween October 2010 and August 2012, ten IAAs were treated in eight males (mean age 75 (59-91) years) using the Multilayer Stent. All IAA exceeded a diameter of 3 cm or were symptomatic. Follow-up (FU) examinations included CT or MR angiography, sonography, and clinical assessment up to 2 years.ResultsPrimary stent placement was technically successful in eight of ten cases. In two cases, severe stent retraction during deployment necessitated placement of an additional stent. Immediately after stent placement, a marked reduction of flow within the sac was observed in all cases (peri-interventional mortality 0 %). During FU, there were two thrombotic stent occlusions, making reintervention necessary (primary patency rate 80 %, secondary patency 100 %). Four IAA were completely occluded at FU, whereas the original vessel and covered branches (n = 8) were patent. In four IAA, there was still residual perfusion. In one patient, IAA diameter decreased slightly, while it remained constant in seven (mean imaging FU 195 (range 1-695) days). There were no adverse events on clinical FU (mean FU 467 (range 101-695) days).ConclusionsOther studies showed the Cardiatis-Multilayer-Stent to be a technically relatively simple treatment option for complex IAA with inadequate landing zones, especially in patients with multiple comorbidities to avoid ipsilateral IIA obstruction. However, in our series complication rate was high. Incomplete sac exclusion, stent-shortening, and thrombotic occlusion can complicate treatment, making meticulous patient selection necessary. Close imaging surveillance is mandatory especially in the early postinterventional period.

  9. Brachial Artery Flow-mediated Dilation Following Exercise with Augmented Oscillatory and Retrograde Shear Rate

    Johnson Blair D

    2012-08-01

    Full Text Available Abstract Background Acute doses of elevated retrograde shear rate (SR appear to be detrimental to endothelial function in resting humans. However, retrograde shear increases during moderate intensity exercise which also enhances post-exercise endothelial function. Since SR patterns differ with the modality of exercise, it is important to determine if augmented retrograde SR during exercise influences post-exercise endothelial function. This study tested the hypothesis that (1 increased doses of retrograde SR in the brachial artery during lower body supine cycle ergometer exercise would attenuate post-exercise flow-mediated dilation (FMD in a dose-dependent manner, and (2 antioxidant vitamin C supplementation would prevent the attenuated post-exercise FMD response. Methods Twelve men participated in four randomized exercise sessions (90 W for 20 minutes on separate days. During three of the sessions, one arm was subjected to increased oscillatory and retrograde SR using three different forearm cuff pressures (20, 40, 60 mmHg (contralateral arm served as the control and subjects ingested placebo capsules prior to exercise. A fourth session with 60 mmHg cuff pressure was performed with 1 g of vitamin C ingested prior to the session. Results Post-exercise FMD following the placebo conditions were lower in the cuffed arm versus the control arm (arm main effect: P P > 0.05. Following vitamin C treatment, post-exercise FMD in the cuffed and control arm increased from baseline (P P > 0.05. Conclusions These results indicate that augmented oscillatory and retrograde SR in non-working limbs during lower body exercise attenuates post-exercise FMD without an evident dose–response in the range of cuff pressures evaluated. Vitamin C supplementation prevented the attenuation of FMD following exercise with augmented oscillatory and retrograde SR suggesting that oxidative stress contributes to the adverse effects of oscillatory and

  10. Intermittent pneumatic leg compressions enhance muscle performance and blood flow in a model of peripheral arterial insufficiency.

    Roseguini, Bruno T; Arce-Esquivel, Arturo A; Newcomer, Sean C; Yang, Hsiao T; Terjung, Ronald; Laughlin, M H

    2012-05-01

    Despite the escalating prevalence in the aging population, few therapeutic options exist to treat patients with peripheral arterial disease. Application of intermittent pneumatic leg compressions (IPC) is regarded as a promising noninvasive approach to treat this condition, but the clinical efficacy, as well the mechanistic basis of action of this therapy, remain poorly defined. We tested the hypothesis that 2 wk of daily application of IPC enhances exercise tolerance by improving blood flow and promoting angiogenesis in skeletal muscle in a model of peripheral arterial insufficiency. Male Sprague-Dawley rats were subjected to bilateral ligation of the femoral artery and randomly allocated to treatment or sham groups. Animals were anesthetized daily and exposed to 1-h sessions of bilateral IPC or sham treatment for 14-16 consecutive days. A third group of nonligated rats was also studied. Marked increases in treadmill exercise tolerance (∼33%, P < 0.05) and improved muscle performance in situ (∼10%, P < 0.05) were observed in IPC-treated animals. Compared with sham-treated controls, blood flow measured with isotope-labeled microspheres during in situ contractions tended to be higher in IPC-treated animals in muscles composed of predominantly fast-twitch white fibers, such as the plantaris (∼93%, P = 0.02). Capillary contacts per fiber and citrate synthase activity were not significantly altered by IPC treatment. Collectively, these data indicate that IPC improves exercise tolerance in a model of peripheral arterial insufficiency in part by enhancing blood flow to collateral-dependent tissues.

  11. Effects of coil closure of patent ductus arteriosus on left anterior descending coronary artery blood flow using transthoracic Doppler echocardiography.

    Harada, Kenji; Toyono, Manotomo; Tamura, Masamichi

    2004-06-01

    Transthoracic Doppler echocardiography provides noninvasive measurements of coronary blood flow in the left anterior descending coronary artery (LAD). This method has the potential to show the effects of acute changes in loading conditions on blood flow. Coil closure of patent ductus arteriosus (PDA) is a model of acute changes in blood pressure and left ventricular (LV) preload that influences coronary blood flow. We applied this technique to assess the coronary blood flow changes for patients with PDA before and immediately after PDA coil closure. We examined 9 patients (1.8 +/- 1.1 years) with simple PDA and 8 age-matched healthy children. LV dimensions and LV mass were measured. Maximum peak flow velocity and flow volume in the LAD were measured. Pulmonary to systemic flow ratios (Qp/Qs) were obtained by cardiac catheterization. After PDA coil closure, LV end-diastolic dimension decreased, and systolic and diastolic blood pressures increased significantly. The maximum peak flow velocity, LAD flow volume, and the ratio of LAD flow volume to LV mass increased significantly. The changes in maximum peak flow velocity and the ratio of LAD flow volume to LV mass (F/M) correlated positively with the changes in diastolic pressure and Qp/Qs. In 5 patients who had Qp/Qs > 1.5, the mean F/M was significantly lower compared with control subjects, but they increased to normal values after coil closure of PDA. PDA coil closure increases diastolic pressure and decreases Qp/Qs, resulting in improvement of myocardial perfusion. These findings provide new insights into the relationship between cardiac function and coronary circulation in pediatric patients with heart diseases associated with PDA.

  12. Measurement of the blood flow rate and velocity in coronary artery stenosis using intracoronary frequency domain optical coherence tomography: Validation against fractional flow reserve.

    Zafar, Haroon; Sharif, Faisal; Leahy, Martin J

    2014-12-01

    The main objective of this study was to assess the blood flow rate and velocity in coronary artery stenosis using intracoronary frequency domain optical coherence tomography (FD-OCT). A correlation between fractional flow reserve (FFR) and FD-OCT derived blood flow velocity is also included in this study. A total of 20 coronary stenoses in 15 patients were assessed consecutively by quantitative coronary angiography (QCA), FFR and FD-OCT. A percutaneous coronary intervention (PCI) optimization system was used in this study which combines wireless FFR measurement and FD-OCT imaging in one platform. Stenoses were labelled severe if FFR ≤ 0.8. Blood flow rate and velocity in each stenosis segment were derived from the volumetric analysis of the FD-OCT pull back images. The FFR value was ≤ 0.80 in 5 stenoses (25%). The mean blood flow rate in severe coronary stenosis ( n  = 5) was 2.54 ± 0.55 ml/s as compared to 4.81 ± 1.95 ml/s in stenosis with FFR > 0.8 ( n  = 15). A good and significant correlation between FFR and FD-OCT blood flow velocity in coronary artery stenosis ( r  = 0.74, p  < 0.001) was found. The assessment of stenosis severity using FD-OCT derived blood flow rate and velocity has the ability to overcome many limitations of QCA and intravascular ultrasound (IVUS).

  13. Effects of exercise training on calf muscle oxygen extraction and blood flow in patients with peripheral artery disease.

    Baker, Wesley B; Li, Zhe; Schenkel, Steven S; Chandra, Malavika; Busch, David R; Englund, Erin K; Schmitz, Kathryn H; Yodh, Arjun G; Floyd, Thomas F; Mohler, Emile R

    2017-12-01

    We employed near-infrared optical techniques, diffuse correlation spectroscopy (DCS), and frequency-domain near-infrared spectroscopy (FD-NIRS) to test the hypothesis that supervised exercise training increases skeletal muscle microvascular blood flow and oxygen extraction in patients with peripheral artery disease (PAD) who experience claudication. PAD patients ( n = 64) were randomly assigned to exercise and control groups. Patients in the exercise group received 3 mo of supervised exercise training. Calf muscle blood flow and oxygen extraction were optically monitored before, during, and after performance of a graded treadmill protocol at baseline and at 3 mo in both groups. Additionally, measurements of the ankle-brachial index (ABI) and peak walking time (PWT) to maximal claudication were made during each patient visit. Supervised exercise training was found to increase the maximal calf muscle blood flow and oxygen extraction levels during treadmill exercise by 29% (13%, 50%) and 8% (1%, 12%), respectively [ P group population were significantly higher than corresponding changes in the control group ( P training also increased PWT by 49% (18%, 101%) ( P = 0.01). However, within statistical error, the ABI, resting calf muscle blood flow and oxygen extraction, and the recovery half-time for hemoglobin\\myoglobin desaturation following cessation of maximal exercise were not altered by exercise training. The concurrent monitoring of both blood flow and oxygen extraction with the hybrid DCS/FD-NIRS instrument revealed enhanced muscle oxidative metabolism during physical activity from exercise training, which could be an underlying mechanism for the observed improvement in PWT. NEW & NOTEWORTHY We report on noninvasive optical measurements of skeletal muscle blood flow and oxygen extraction dynamics before/during/after treadmill exercise in peripheral artery disease patients who experience claudication. The measurements tracked the effects of a 3-mo supervised

  14. Induced renal artery stenosis in rabbits: magnetic resonance imaging, angiography, and radionuclide determination of blood volume and blood flow

    Mitchell, D.G.; Tobin, M.; LeVeen, R.; Tomaczewski, J.; Alavi, A.; Staum, M.; Kundel, H.

    1988-01-01

    To investigate the ability of MRI to detect alterations due to renal ischemia, a rabbit renal artery stenosis (RAS) model was developed. Seven rabbits had RAS induced by surgically encircling the artery with a polyethylene band which had a lumen of 1 mm, 1 to 2 weeks prior to imaging. The stenosis was confirmed by angiography, and the rabbits were then imaged in a 1.4 T research MRI unit. T1 was calculated using four inversion recovery sequences with different inversion times. Renal blood flow, using 113 Sn-microspheres, and regional water content by drying were then measured. The average T1 of the inner medulla was shorter for the ischemia (1574 msec) than for the contralateral kidney (1849 msec), while no change ws noted in the cortex. Ischemic kidneys had less distinct outer medullary zones on IR images with TI = 600 msec than did contralateral or control kidneys. Blood flow to both the cortex and medulla were markedly reduced in ischemic kidneys compared with contralateral kidneys (119.5 vs. 391 ml/min/100 gm for cortex and 19.8 vs. 50.8 ml/min/100 gm for medulla). Renal water and blood content were less affected. Our rabbit model of renal artery stenosis with MRI, radionuclide, and angiographic correlation has the potential to increase our understanding of MR imaging of the rabbit kidney

  15. Effect of captopril on renal blood flow in renal artery stenosis assessed by positron tomography with rubidium-82

    Tamaki, N.; Alpert, N.M.; Rabito, C.A.; Barlai-Kovach, M.; Correia, J.A.; Strauss, H.W.

    1988-01-01

    The sequence and magnitude of acute changes in renal blood flow following administration of captopril were determined in a canine model of acute unilateral renal artery stenosis using rubidium-82 and positron emission tomography. Data were recorded in each of nine dogs under three conditions: 1) during a baseline control interval, 2) during renal artery stenosis, and 3) during stenosis with intravenous injection of captopril (1.2 mg/kg). Mean arterial blood pressure was 108 +/- 12 mm Hg at control, increased significantly to 125 +/- 13 mm Hg (p less than 0.01) during stenosis, and decreased to 98 +/- 13 mm/Hg (p less than 0.01) after captopril infusion. Mean renal blood flow was calculated using a steady state single compartment model from the images produced by positron emission tomography. The estimated flow to the affected kidney was 3.37 +/- 1.48 ml/min/g at control, 0.86 +/- 0.62 ml/min/g during stenosis (p less than 0.01), and 0.64 +/- 0.57 ml/min/g after captopril administration (p = NS compared with precaptopril value). The estimated flow to the contralateral kidney was minimally reduced from a baseline of 3.84 +/- 0.95 to 3.24 +/- 1.13 ml/min/g (p = NS) during stenosis and increased after captopril infusion (4.08 +/- 0.94 ml/min/g; p = 0.01). These data suggest that repetitive imaging with positron emission tomography can be used to delineate acute changes in renal perfusion following captopril administration

  16. Cerebral blood flow measured by arterial spin labeling MRI at resting state in normal aging and Alzheimer's disease.

    Zhang, Nan; Gordon, Marc L; Goldberg, Terry E

    2017-01-01

    Arterial spin labeling (ASL) magnetic resonance imaging uses arterial blood water as an endogenous tracer to measure cerebral blood flow (CBF). In this review, based on ASL studies in the resting state, we discuss state-of-the-art technical and data processing improvements in ASL, and ASL CBF changes in normal aging, mild cognitive impairment (MCI), Alzheimer's disease (AD), and other types of dementia. We propose that vascular and AD risk factors should be considered when evaluating CBF changes in aging, and that other validated biomarkers should be used as inclusion criteria or covariates when evaluating CBF changes in MCI and AD. With improvements in hardware and experimental design, ASL is proving to be an increasingly promising tool for exploring pathogenetic mechanisms, early detection, monitoring disease progression and pharmacological response, and differential diagnosis of AD. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  17. Novel Software-Assisted Hemodynamic Evaluation of Pelvic Flow During Chemoperfusion of Pelvic Arteries for Bladder Cancer: Double- Versus Single-Balloon Technique

    Yamamoto, Kiyohito, E-mail: rad105@poh.osaka-med.ac.jp; Yamamoto, Kazuhiro, E-mail: rad043@poh.osaka-med.ac.jp; Nakai, Go, E-mail: rad091@poh.osaka-med.ac.jp [Osaka Medical College, Department of Radiology (Japan); Azuma, Haruhito, E-mail: uro004@poh.osaka-med.ac.jp [Osaka Medical College, Department of Urology (Japan); Narumi, Yoshifumi, E-mail: narumi@poh.osaka-med.ac.jp [Osaka Medical College, Department of Radiology (Japan)

    2016-06-15

    PurposeApproximately 83 % of patients with bladder cancer have achieved a complete response after undergoing a novel bladder preservation therapy involving balloon-occluded intra-arterial infusion chemotherapy (BOAI) using a four-lumen double-balloon catheter, known as the Osaka Medical College regimen. This study aimed to show the quantitative difference in hemodynamics of the bladder arteries using syngo iFlow (Siemens Healthcare, Erlangen, Germany), which provides an automatic tool for quantitative blood flow analysis between double BOAI (D-BOAI) and conventional single BOAI (S-BOAI).Materials and MethodsFifty patients were included. The catheters were introduced into both posterior trunks of the internal iliac arteries via contralateral femoral artery access. A side hole between the distal and proximal balloons was placed at the origin of each bladder artery to allow clear visualization of angiographic flow of the injected agent into the urinary bladder. Digital subtraction angiography was used during analysis with the syngo iFlow to evaluate the hemodynamics of the contrast medium in the pelvic arteries during BOAI. The comparative change in the amount of contrast medium in the bladder arteries between D-BOAI and S-BOAI was assessed using syngo iFlow.ResultsOne-hundred pelvic sides were analyzed. The amount of contrast medium in the bladder arteries using D-BOAI was more than twice that using S-BOAI (right, 3.03-fold; left, 2.81-fold).ConclusionThe amount of contrast medium in the bladder arteries using D-BOAI was higher than that using conventional S-BOAI. This may increase the anticancer drug concentration in the affected bladder, leading to a good clinical response.

  18. Fractional flow reserve versus angiography for guiding percutaneous coronary intervention in patients with multivessel coronary artery disease: 2-year follow-up of the FAME (Fractional Flow Reserve Versus Angiography for Multivessel Evaluation) study

    Pijls, Nico H J; Fearon, William F; Tonino, Pim A L

    2010-01-01

    The purpose of this study was to investigate the 2-year outcome of percutaneous coronary intervention (PCI) guided by fractional flow reserve (FFR) in patients with multivessel coronary artery disease (CAD)....

  19. Flow-mediated dilation and peripheral arterial tonometry are disturbed in preeclampsia and reflect different aspects of endothelial function.

    Mannaerts, Dominique; Faes, Ellen; Goovaerts, Inge; Stoop, Tibor; Cornette, Jerome; Gyselaers, Wilfried; Spaanderman, Marc; Van Craenenbroeck, Emeline M; Jacquemyn, Yves

    2017-11-01

    Endothelial function and arterial stiffness are known to be altered in preeclamptic pregnancies. Previous studies have shown conflicting results regarding the best technique for assessing vascular function in pregnancy. In this study, we made a comprehensive evaluation of in vivo vascular function [including flow-mediated dilatation (FMD), peripheral arterial tonometry (PAT), and arterial stiffness] in preeclamptic patients and compared them with normal pregnancies. In addition, we assessed the relation between vascular function and systemic inflammation. Fourteen patients with preeclampsia (PE) and 14 healthy pregnant controls were included. Endothelial function was determined by FMD and PAT and arterial stiffness by carotid-femoral pulse-wave velocity and augmentation index. Systemic inflammation was assessed using mean platelet volume (MPV) and neutrophil-lymphocyte ratio (NLR). The reactive hyperemia index, assessed using PAT, is decreased at the third trimester compared with the first trimester in a normal, uncomplicated pregnancy ( P = 0.001). Arterial stiffness is significantly higher in PE versus normal pregnancy ( P function, obtained by FMD, is deteriorated in PE versus normal pregnancy ( P = 0.015), whereas endothelial function assessment by PAT is improved in PE versus normal pregnancy ( P = 0.001). Systemic inflammation (MPV and NLR) increases during normal pregnancy. FMD and PAT are disturbed in PE. Endothelial function, assessed by FMD and PAT, shows distinct results. This may indicate that measurements with FMD and PAT reflect different aspects of endothelial function and that PAT should not be used as a substitute for FMD as a measure of endothelial function in pregnancy. Copyright © 2017 the American Physiological Society.

  20. Analysis of flow and LDL concentration polarization in siphon of internal carotid artery: Non-Newtonian effects.

    Sharifi, Alireza; Niazmand, Hamid

    2015-10-01

    Carotid siphon is known as one of the risky sites among the human intracranial arteries, which is prone to formation of atherosclerotic lesions. Indeed, scientists believe that accumulation of low density lipoprotein (LDL) inside the lumen is the major cause of atherosclerosis. To this aim, three types of internal carotid artery (ICA) siphon have been constructed to examine variations of hemodynamic parameters in different regions of the arteries. Providing real physiological conditions, blood considered as non-Newtonian fluid and real velocity and pressure waveforms have been employed as flow boundary conditions. Moreover, to have a better estimation of risky sites, the accumulation of LDL particles has been considered, which has been usually ignored in previous relevant studies. Governing equations have been discretized and solved via open source OpenFOAM software. A new solver has been built to meet essential parameters related to the flow and mass transfer phenomena. In contrast to the common belief regarding negligible effect of blood non-Newtonian behavior inside large arteries, current study suggests that the non-Newtonian blood behavior is notable, especially on the velocity field of the U-type model. In addition, it is concluded that neglecting non-Newtonian effects underestimates the LDL accumulation up to 3% in the U-type model at the inner side of both its bends. However, in the V and C type models, non-Newtonian effects become relatively small. Results also emphasize that the outer part of the second bend at the downstream is also at risk similar to the inner part of the carotid bends. Furthermore, from findings it can be implied that the risky sites strongly depend on the ICA shape since the extension of the risky sites are relatively larger for the V-type model, while the LDL concentrations are higher for the C-type model. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Estimation of coronary flow reserve by sestamibi imaging in patients with mild hypertension and normal coronary arteries

    Storto, G.; Gallicchio, R.; Maddalena, F.; Pellegrino, T.; Petretta, M.; Fiumara, G.; Cuocolo, A.

    2015-01-01

    Patients with hypertension may exhibit abnormal vasodilator capacity during pharmacological vasodilatation. We assessed coronary flow reserve (CFR) by sestamibi imaging in hypertensive patients with normal coronary vessels. Twenty-five patients with untreated mild essential hypertension and normal coronary vessels and 10 control subjects underwent dipyridamole-rest Tc-99m sestamibi imaging. Myocardial blood flow (MBF) was estimated by measuring first transit counts in pulmonary artery and myocardial counts from tomograhic images. CFR was expressed as the ratio of stress to rest MBF. Coronary vascular resistances (CVR) were computed as the ratio between mean arterial pressure and MBF. Estimated MBF at rest was not different in patients and controls (1.11±0.59 vs. 1.14±0.28 counts/pixel/s; P=0.87). Conversely, stress MBF was lower in patients than in controls (1.55±0.47 vs. 2.68±0.53 counts/pixel/s; P<0.001). Thus, CFR was reduced in patients compared to controls (1.61±0.58 vs. 2.43±0.62; P<0.001). Rest and stress CVR values were higher in patients (P<0.001), while stress-induced changes in CVR were not different (P=0.08) between patients (-51%) and controls (-62%). In the overall study population, a significant relation between CFR and stress-induced changes in CVR was observed (r=-0.86; P<0.001). Sestamibi imaging may detect impaired coronary vascular function in response to dipyridamole in patients with untreated mild essential hypertension and normal coronary arteries. A mild increase in arterial blood pressure does not affect baseline MBF, but impairs coronary reserve due to the amplified resting coronary resistances.

  2. A control systems approach to quantify wall shear stress normalization by flow-mediated dilation in the brachial artery.

    Frank C G van Bussel

    Full Text Available Flow-mediated dilation is aimed at normalization of local wall shear stress under varying blood flow conditions. Blood flow velocity and vessel diameter are continuous and opposing influences that modulate wall shear stress. We derived an index FMDv to quantify wall shear stress normalization performance by flow-mediated dilation in the brachial artery. In 22 fasting presumed healthy men, we first assessed intra- and inter-session reproducibilities of two indices pFMDv and mFMDv, which consider the relative peak and relative mean hyperemic change in flow velocity, respectively. Second, utilizing oral glucose loading, we evaluated the tracking performance of both FMDv indices, in comparison with existing indices [i.e., the relative peak diameter increase (%FMD, the peak to baseline diameter ratio (Dpeak/Dbase, and the relative peak diameter increase normalized to the full area under the curve of blood flow velocity with hyperemia (FMD/shearAUC or with area integrated to peak hyperemia (FMD/shearAUC_peak]. Inter-session and intra-session reproducibilities for pFMDv, mFMDv and %FMD were comparable (intra-class correlation coefficients within 0.521-0.677 range. Both pFMDv and mFMDv showed more clearly a reduction after glucose loading (reduction of ~45%, p≤0.001 than the other indices (% given are relative reductions: %FMD (~11%, p≥0.074; Dpeak/Dbase (~11%, p≥0.074; FMD/shearAUC_peak (~20%, p≥0.016 and FMD/shearAUC (~38%, p≤0.038. Further analysis indicated that wall shear stress normalization under normal (fasting conditions is already far from ideal (FMDv << 1, which (therefore does not materially change with glucose loading. Our approach might be useful in intervention studies to detect intrinsic changes in shear stress normalization performance in conduit arteries.

  3. Spinal cord blood flow and ischemic injury after experimental sacrifice of thoracic and abdominal segmental arteries.

    Etz, Christian D; Homann, Tobias M; Luehr, Maximilian; Kari, Fabian A; Weisz, Donald J; Kleinman, George; Plestis, Konstadinos A; Griepp, Randall B

    2008-06-01

    Spinal cord blood flow (SCBF) after sacrifice of thoracoabdominal aortic segmental arteries (TAASA) during thoracoabdominal aortic aneurysm (TAAA) repair remains poorly understood. This study explored SCBF for 72 h after sacrifice of all TAASA. Fourteen juvenile Yorkshire pigs underwent complete serial TAASA sacrifice (T4-L5). Six control pigs underwent anesthesia and cooling to 32 degrees C with no TAASA sacrifice. In the experimental animals, spinal cord function was continuously monitored using motor evoked potentials (MEPs) until 1h after clamping the last TAASA. Fluorescent microspheres enabled segmental measurement of SCBF along the entire spinal cord before, and 5 min, 1 h, 5 h, 24 h and 72 h after complete TAASA sacrifice. A modified Tarlov score was obtained for 3 days after surgery. All the pigs with complete TAASA sacrifice retained normal cord function (MEP) until 1h after TAASA ligation. Seven pigs (50%) with complete TAASA sacrifice recovered after 72 h; seven pigs suffered paraparesis or paraplegia. Intraoperatively, and until 1h postoperatively, SCBF was similar among the three groups along the entire cord. Postoperatively, SCBF did not decrease in any group, but significant hyperemia occurred at 5h in controls and recovery animals, but did not occur in pigs that developed paraparesis or paraplegia in the T8-L2 segments (p=0.0002) and L3-S segments (p=0.0007). At 24h, SCBF remained marginally lower from T8 caudally; at 72h, SCBF was similar among all groups along the entire cord. SCBF in the segments T8-L2 at 5h predicted functional recovery (p=0.003). This study suggests that critical spinal cord ischemia after complete TAASA sacrifice does not occur immediately (intraoperatively), but is delayed 1-5h or longer after clamping, and represents failure to mount a hyperemic response to rewarming and awakening. The short duration of low SCBF associated with spinal cord injury suggests that hemodynamic and metabolic manipulation lasting only 24-72 h may

  4. Blood flow parameters of the superior mesenteric artery as an early predictor of intestinal dysmotility in preterm infants

    Robel-Tillig, Eva; Knuepfer, Matthias; Pulzer, Ferdinand; Vogtmann, Christoph

    2004-01-01

    Blood flow parameters in the superior mesenteric artery (SMA) change with vasoconstriction or vasodilatation of the intestinal vascular bed. In cases of severe growth retardation as a result of haemodynamic disturbances, the blood flow changes persist into postnatal life. To assess early changes of Doppler sonographic blood flow parameters in the SMA for prediction of later intestinal motility disturbances in preterm infants and tolerance of enteral feeding during the first week of life. Doppler sonographic blood flow parameters in the SMA were measured on the first day of life and the following 5 days in 478 neonates with a birth weight below 1,500 g. According to the Doppler results, the neonates were divided into two groups - those with pathological parameters and those with normal blood flow parameters. Correlations between blood flow parameters, the development of intestinal dysmotility and the tolerated amount of enteral feeding were calculated. Pathological blood flow parameters were observed in 148 neonates (group 1) and normal blood flow parameters in 330 neonates (group 2). Intestinal motility disturbance occurred in 125 neonates (83%) of group 1 and 47 neonates (15%) of group 2. Neonates in group 2 tolerated significantly more feed by the fifth day of life than neonates in group 1. Postnatal adaptation did not differ between the two groups, although the majority of neonates with intestinal dysmotility were small for gestational age. The predictive value of blood flow parameters for prediction of intestinal motility revealed high sensitivity and specificity by the first postnatal day, 2 or 3 days before development of clinical signs of intestinal dysmotility. There was a strong negative correlation between pathological pulsatility index on day 1 and the quantity of tolerated enteral feeding on day 5. Pathological blood flow parameters in the SMA can predict problems of intestinal motility and tolerance of enteral feeding. With the early detection of these

  5. QUANTITATIVE CHANGES IN REGIONAL CEREBRAL BLOOD FLOW INDUCED BY COLD, HEAT AND ISCHEMIC PAIN: A CONTINUOUS ARTERIAL SPIN LABELING STUDY

    Frölich, Michael A.; Deshpande, Hrishikesh; Ness, Timothy; Deutsch, Georg

    2012-01-01

    Background The development of arterial spin labeling methods, has allowed measuring regional cerebral blood flow (rCBF) quantitatively and to show the pattern of cerebral activity associated with any state such as a sustained pain state or changes due to a neurotropic drug. Methods We studied the differential effects of three pain conditions in ten healthy subjects on a 3T scanner during resting baseline, heat, cold and ischemic pain using continuous arterial spin labeling. Results Cold pain showed the greatest absolute rCBF increases in left anterior cingulate cortex, left amygdala, left angular gyrus, and Brodmann Area 6, and a significant rCBF decrease in the cerebellum. Changes in rCBF were characteristic of the type of pain condition: cold and heat pain showed increases, while the ischemic condition showed a reduction in mean absolute gray matter flow compared to rest. An association of subjects’ pain tolerance and cerebral blood flow was noted. Conclusions The observation that quantitative rCBF changes are characteristic of the pain task employed and that there is a consistent rCBF change in Brodman area 6, an area responsible for the integration of a motor response to pain, should provide extremely useful information in the quest to develop an imaging biomarker of pain. Conceivably, response in BA6 may serve as an objective measure of analgesic efficacy. PMID:22913924

  6. Reduced peripheral arterial blood flow with preserved cardiac output during submaximal bicycle exercise in elderly heart failure

    Leng Xiaoyan

    2009-11-01

    Full Text Available Abstract Background Older heart failure (HF patients exhibit exercise intolerance during activities of daily living. We hypothesized that reduced lower extremity blood flow (LBF due to reduced forward cardiac output would contribute to submaximal exercise intolerance in older HF patients. Methods and Results Twelve HF patients both with preserved and reduced left ventricular ejection fraction (LVEF (aged 68 ± 10 years without large (aorta or medium sized (iliac or femoral artery vessel atherosclerosis, and 13 age and gender matched healthy volunteers underwent a sophisticated battery of assessments including a peak exercise oxygen consumption (peak VO2, b physical function, c cardiovascular magnetic resonance (CMR submaximal exercise measures of aortic and femoral arterial blood flow, and d determination of thigh muscle area. Peak VO2 was reduced in HF subjects (14 ± 3 ml/kg/min compared to healthy elderly subjects (20 ± 6 ml/kg/min (p = 0.01. Four-meter walk speed was 1.35 ± 0.24 m/sec in healthy elderly verses 0.98 ± 0.15 m/sec in HF subjects (p p ≤ 0.03. Conclusion During CMR submaximal bike exercise in the elderly with heart failure, mechanisms other than low cardiac output are responsible for reduced lower extremity blood flow.

  7. Quantitative changes in regional cerebral blood flow induced by cold, heat and ischemic pain: a continuous arterial spin labeling study.

    Frölich, Michael A; Deshpande, Hrishikesh; Ness, Timothy; Deutsch, Georg

    2012-10-01

    The development of arterial spin labeling methods has allowed measuring regional cerebral blood flow (rCBF) quantitatively and to show the pattern of cerebral activity associated with any state such as a sustained pain state or changes due to a neurotropic drug. The authors studied the differential effects of three pain conditions in 10 healthy subjects on a 3 Tesla scanner during resting baseline, heat, cold, and ischemic pain using continuous arterial spin labeling. Cold pain showed the greatest absolute rCBF increases in left anterior cingulate cortex, left amygdala, left angular gyrus, and Brodmann area 6, and a significant rCBF decrease in the cerebellum. Changes in rCBF were characteristic of the type of pain condition: cold and heat pain showed increases, whereas the ischemic condition showed a reduction in mean absolute gray matter flow compared with rest. An association of subjects' pain tolerance and cerebral blood flow was noted. The observation that quantitative rCBF changes are characteristic of the pain task used and that there is a consistent rCBF change in Brodman area 6, an area responsible for the integration of a motor response to pain, should provide extremely useful information in the quest to develop an imaging biomarker of pain. Conceivably, response in BA6 may serve as an objective measure of analgesic efficacy.

  8. Quantitative relationship between coronary artery calcium and myocardial blood flow by hybrid rubidium-82 PET/CT imaging in patients with suspected coronary artery disease.

    Assante, Roberta; Zampella, Emilia; Arumugam, Parthiban; Acampa, Wanda; Imbriaco, Massimo; Tout, Deborah; Petretta, Mario; Tonge, Christine; Cuocolo, Alberto

    2017-04-01

    We assessed the relationship between coronary artery calcium (CAC) score, myocardial blood flow (MBF) and coronary flow reserve (CFR) in patients undergoing hybrid 82 Rb positron emission tomography (PET)/computed tomography (CT) imaging for suspected CAD. We also evaluated if CAC score is able to predict a reduced CFR independently from conventional coronary risk factors. A total of 637 (mean age 58 ± 13 years) consecutive patients were studied. CAC score was measured according to the Agatston method and patients were categorized into 4 groups (0, 0.01-99.9, 100-399.9, and ≥400). Baseline and hyperemic MBF were automatically quantified. CFR was calculated as the ratio of hyperemic to baseline MBF and it was considered reduced when <2. Global CAC score showed a significant inverse correlation with hyperemic MBF and CFR (both P < .001), while no correlation between CAC score and baseline MBF was found. At multivariable logistic regression analysis age, diabetes and CAC score were independently associated with reduced CFR (all P < .001). The addition of CAC score to clinical data increased the global chi-square value for predicting reduced CFR from 81.01 to 91.13 (P < .01). Continuous net reclassification improvement, obtained by adding CAC score to clinical data, was 0.36. CAC score provides incremental information about coronary vascular function over established CAD risk factors in patients with suspected CAD and it might be helpful for identifying those with a reduced CFR.

  9. Metformin, but not glimepiride, improves carotid artery diameter and blood flow in patients with type 2 diabetes mellitus

    Helena Atroch Machado

    2012-07-01

    Full Text Available OBJECTIVE: To compare the effects of glimepiride and metformin on vascular reactivity, hemostatic factors and glucose and lipid profiles in patients with type 2 diabetes. METHODS: A prospective study was performed in 16 uncontrolled patients with diabetes previously treated with dietary intervention. The participants were randomized into metformin or glimepiride therapy groups. After four months, the patients were crossed over with no washout period to the alternative treatment for an additional four-month period on similar dosage schedules. The following variables were assessed before and after four months of each treatment: 1 fasting glycemia, insulin, catecholamines, lipid profiles and HbA1 levels; 2 t-PA and PAI-1 (antigen and activity, platelet aggregation and fibrinogen and plasminogen levels; and 3 the flow indices of the carotid and brachial arteries. In addition, at the end of each period, a 12-hour metabolic profile was obtained after fasting and every 2 hours thereafter. RESULTS: Both therapies resulted in similar decreases in fasting glucose, triglyceride and norepinephrine levels, and they increased the fibrinolytic factor plasminogen but decreased t-PA activity. Metformin caused lower insulin and pro-insulin levels and higher glucagon levels and increased systolic carotid diameter and blood flow. Neither metformin nor glimepiride affected endothelial-dependent or endothelial-independent vasodilation of the brachial artery. CONCLUSIONS: Glimepiride and metformin were effective in improving glucose and lipid profiles and norepinephrine levels. Metformin afforded more protection against macrovascular diabetes complications, increased systolic carotid artery diameter and total and systolic blood flow, and decreased insulin levels. As both therapies increased plasminogen levels but reduced t-PA activity, a coagulation process was likely still ongoing.

  10. The effects of cigarette smoking on intraocular pressure and arterial ...

    This study was designed to determine the effects of cigarette Smoking on intra ocular pressure and arterial blood pressure of normotensive young male adults. Fifty male students (who met the screening conditions and devoid of obvious ocular pathology and systemic diseases and nonsmokers) had their intra ocular ...

  11. Significance of preoperative cerebral blood flow measurements in endovascular occlusion of the internal carotid and middle cerebral arteries

    Laurent, A.; Weitzner, I.; Luft, A.; Merland, J.J.

    1988-01-01

    Cerebral blood flow (CBF) measurements during 12 endovascular balloon occlusions (ten internal carotid and two middle cerebral arteries) with good clinical and angiographic tolerance were done with repeated boluses of Xe-133 injected directly into the ipsi- and contralateral carotid systems, during the occlusion and repeated measurements with detectors on both sides (before occlusion and 5-30 minutes after occlusion). In two cases of unchanged and four of increased CBF, one reversible deficit was probably due to an embolus. In six cases of decreased CBF, two deficits occurred, characterized by a greater than 25% decrease. It seems to represent a good predictive value for intolerance to occlusion

  12. First-line intra-arterial versus intravenous chemotherapy in unilateral sporadic group D retinoblastoma: evidence of better visual outcomes, ocular survival and shorter time to success with intra-arterial delivery from retrospective review of 20 years of treatment.

    Munier, Francis L; Mosimann, Pascal; Puccinelli, Francesco; Gaillard, Marie-Claire; Stathopoulos, Christina; Houghton, Susan; Bergin, Ciara; Beck-Popovic, Maja

    2017-08-01

    The introduction of intra-arterial chemotherapy (IAC) as salvage treatment has improved the prognosis for eye conservation in group D retinoblastoma. The aim of this study was to compare the outcomes of consecutive patients with advanced unilateral disease treated with either first-line intravenous chemotherapy (IVC) or first-line IAC. This is a retrospective mono-centric comparative review of consecutive patients. Sporadic unilateral retinoblastoma group D cases treated conservatively at Jules-Gonin Eye Hospital and CHUV between 1997 and 2014. From January 1997 to August 2008, IVC, combined with focal treatments, was the primary treatment approach. From September 2008 to October 2014, IAC replaced IVC as first-line therapy. 48 patients met the inclusion criteria, receiving only either IAC or IVC as primary treatment modality. Outcomes of 23 patients treated by IVC were compared with those of 25 treated by IAC; mean follow-up was 105.3 months (range 29.2-218.6) and 41.7 months (range 19.6-89.5), respectively. Treatment duration was significantly shorter in the IAC group (pchemotherapy treatment. Despite this, the results reported here imply that eyes treated with first-line IAC will have shorter treatment period, better ocular survival and visual acuity than first-line IVC. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  13. Miopatia ocular descendente

    Marcos R. G. de Freitas

    1975-06-01

    Full Text Available Os autores apresentam caso de paciente jovem, do sexo feminino, com afecção muscular primária ocular e faríngea sem caráter familial. Foram feitos estudos eletromiográficos e histopatológicos musculares que confirmam o caráter miogênico do processo. É feita comparação entre a miopatia ocular e a miopatia ocular descendente, acreditando os autores que seriam variantes

  14. Cerebral blood flow and cerebrovascular reserve capacity in patients with occlusion or severe stenosis of cerebral arterial trunk

    Yoshinaga, Shinya; Tanaka, Akira; Nakayama, Yoshiya; Tomonaga, Masamichi [Fukuoka Univ., Chikushino (Japan). Chikushi Hospital

    1997-12-01

    The cerebral blood flow (CBF) and the cerebrovascular reserve capacity (CVRC) were sequentially measured using a xenon enhanced CT scan in patients with transient ischemic attack or minor stroke due to an occlusion or a severe stenosis of the cerebral arterial trunk. The patients consisted of twelve males and one female ranging from 37 to 71 years of age (53 years on average). The vascular lesion was located in the internal carotid artery (7 patients) and in the middle cerebral artery (6 patients). Eleven patients received antiplatelet drug therapy, while two other patients underwent STA-MCA anastomosis. The CBF measurements were initially done within one month after the attack and then from 6 to 24 months (12 months on average) after the first study. Only one of 13 patients demonstrated a reattack during the period of observation and the CVRC decreased to 0% from the 14% level observed prior to the reattack, although the CBF was preserved. In the other twelve patients without a reattack, the CVRC was found to improve to 29.4% from 9.9% with statistical significance, even though the CBF remained the same in the first study. This study suggests hemodynamic insult to be closely related to the decreased in the CVRC, while STA-MCA anastomosis does not for prevent hemodynamic reattack based on a decrease in the CVRC in the early stage. (author)

  15. Cluster bomb ocular injuries.

    Mansour, Ahmad M; Hamade, Haya; Ghaddar, Ayman; Mokadem, Ahmad Samih; El Hajj Ali, Mohamad; Awwad, Shady

    2012-01-01

    To present the visual outcomes and ocular sequelae of victims of cluster bombs. This retrospective, multicenter case series of ocular injury due to cluster bombs was conducted for 3 years after the war in South Lebanon (July 2006). Data were gathered from the reports to the Information Management System for Mine Action. There were 308 victims of clusters bombs; 36 individuals were killed, of which 2 received ocular lacerations and; 272 individuals were injured with 18 receiving ocular injury. These 18 surviving individuals were assessed by the authors. Ocular injury occurred in 6.5% (20/308) of cluster bomb victims. Trauma to multiple organs occurred in 12 of 18 cases (67%) with ocular injury. Ocular findings included corneal or scleral lacerations (16 eyes), corneal foreign bodies (9 eyes), corneal decompensation (2 eyes), ruptured cataract (6 eyes), and intravitreal foreign bodies (10 eyes). The corneas of one patient had extreme attenuation of the endothelium. Ocular injury occurred in 6.5% of cluster bomb victims and 67% of the patients with ocular injury sustained trauma to multiple organs. Visual morbidity in civilians is an additional reason for a global ban on the use of cluster bombs.

  16. Increasing arterial blood pressure with norepinephrine does not improve microcirculatory blood flow: a prospective study

    Dubin, Arnaldo; Pozo, Mario O.; Casabella, Christian A.; Palizas, Fernando; Murias, Gaston; Moseinco, Miriam C.; Kanoore Edul, Vanina S.; Estenssoro, Elisa; Ince, Can

    2009-01-01

    Introduction Our goal was to assess the effects of titration of a norepinephrine infusion to increasing levels of mean arterial pressure (MAP) on sublingual microcirculation. Methods Twenty septic shock patients were prospectively studied in two teaching intensive care units. The patients were

  17. Collateral flow predicts outcome after basilar artery occlusion : The posterior circulation collateral score

    van der Hoeven, Erik J R J; McVerry, Ferghal; Vos, Jan Albert; Algra, Ale; Puetz, Volker; Kappelle, L. Jaap; Schonewille, Wouter J.

    2016-01-01

    BACKGROUND AND AIM: Our aim was to assess the prognostic value of a semiquantitative computed tomography angiography-based grading system, for the prediction of outcome in patients with acute basilar artery occlusion, based on the presence of potential collateral pathways on computed tomography

  18. Ocular manifestations of injection drug use.

    Kim, Rubin W; Juzych, Mark S; Eliott, Dean

    2002-09-01

    Injection drug use can result in a variety of severe ocular conditions. Hematogenous dissemination of various fungi and bacteria may produce endophthalmitis with resultant severe visual loss. Retinal arterial occlusive disease may result from talc and other particulate emboli. Most commonly, life-threatening systemic diseases such as endocarditis and HIV infection secondarily affect the eye. Because many of these conditions may result in blindness if untreated, accurate diagnosis and prompt initiation of therapy are essential.

  19. Evaluation of Renal Blood Flow in Chronic Kidney Disease Using Arterial Spin Labeling Perfusion Magnetic Resonance Imaging.

    Li, Lu-Ping; Tan, Huan; Thacker, Jon M; Li, Wei; Zhou, Ying; Kohn, Orly; Sprague, Stuart M; Prasad, Pottumarthi V

    2017-01-01

    Chronic kidney disease (CKD) is known to be associated with reduced renal blood flow. However, data to-date in humans is limited. In this study, non-invasive arterial spin labeling (ASL) MRI data was acquired in 33 patients with diabetes and stage-3 CKD, and 30 healthy controls. A significantly lower renal blood flow both in cortex (108.4±36.4 vs . 207.3±41.8; pblood flow were correlated with eGFR, and cortical blood flow was found to be confounded by age and BMI. However, in a subset of subjects that were matched for age and BMI (n=6), the differences between CKD and control subjects remained significant both in cortex (107.4±42.8 vs . 187.51±20.44; p=0.002) and medulla (15.43±8.43 vs . 39.18±11.13; p=0.002). A threshold value to separate healthy and CKD was estimated to be Cor_BF=142.9 and Med_BF=24.1. These results support the use of ASL in the evaluation of renal blood flow in patients with moderate level of CKD. Whether these measurements can identify subjects at risk of progressive CKD requires further longitudinal follow-up.

  20. Effects of respiratory alkalosis and acidosis on myocardial blood flow and metabolism in patients with coronary artery disease.

    Kazmaier, S; Weyland, A; Buhre, W; Stephan, H; Rieke, H; Filoda, K; Sonntag, H

    1998-10-01

    Variation of the arterial carbon dioxide partial pressure (PaCO2) is not uncommon in anesthetic practice. However, little is known about the myocardial consequences of respiratory alkalosis and acidosis, particularly in patients with coronary artery disease. The aim of the current study was to investigate the effects of variation in PaCO2 on myocardial blood flow (MBF), metabolism, and systemic hemodynamics in patients before elective coronary artery bypass graft surgery. In 10 male anesthetized patients, measurements of MBF, myocardial contractility, metabolism, and systemic hemodynamics were made in a randomized sequence at PaCO2 levels of 30, 40, and 50 mmHg, respectively. The MBF was measured using the Kety-Schmidt technique with argon as a tracer. End-diastolic left ventricular pressure and the maximal increase of left ventricular pressure were assessed using a manometer-tipped catheter. The cardiac index significantly changed with varying PaCO2 levels (hypocapnia, - 9%; hypercapnia, 13%). This reaction was associated with inverse changes in systemic vascular resistance index levels. The MBF significantly increased by 15% during hypercapnia, whereas no change was found during hypocapnia. Myocardial oxygen and glucose uptake and the maximal increase of left ventricular pressure were not affected by varying PaCO2 levels. In anesthetized patients with coronary artery disease, short-term variations in PaCO2 have significant effects on MBF but do not influence global myocardial oxygen and glucose uptake. Changes in systemic hemodynamics associated with respiratory alkalosis and acidosis are caused by changes in systemic vascular resistance rather than by alterations in myocardial contractility.

  1. Investigation of the relative effects of vascular branching structure and gravity on pulmonary arterial blood flow heterogeneity via an image-based computational model.

    Burrowes, Kelly S; Hunter, Peter J; Tawhai, Merryn H

    2005-11-01

    A computational model of blood flow through the human pulmonary arterial tree has been developed to investigate the relative influence of branching structure and gravity on blood flow distribution in the human lung. Geometric models of the largest arterial vessels and lobar boundaries were first derived using multidetector row x-ray computed tomography (MDCT) scans. Further accompanying arterial vessels were generated from the MDCT vessel endpoints into the lobar volumes using a volume-filling branching algorithm. Equations governing the conservation of mass and momentum were solved within the geometric model to calculate pressure, velocity, and vessel radius. Blood flow results in the anatomically based model, with and without gravity, and in a symmetric geometric model were compared to investigate their relative contributions to blood flow heterogeneity. Results showed a persistent blood flow gradient and flow heterogeneity in the absence of gravitational forces in the anatomically based model. Comparison with flow results in the symmetric model revealed that the asymmetric vascular branching structure was largely responsible for producing this heterogeneity. Analysis of average results in varying slice thicknesses illustrated a clear flow gradient because of gravity in "lower resolution" data (thicker slices), but on examination of higher resolution data, a trend was less obvious. Results suggest that although gravity does influence flow distribution, the influence of the tree branching structure is also a dominant factor. These results are consistent with high-resolution experimental studies that have demonstrated gravity to be only a minor determinant of blood flow distribution.

  2. Determinants of leptomeningeal collateral flow in stroke patients with a middle cerebral artery occlusion

    van Seeters, Tom; Biessels, Geert Jan; Kappelle, L. Jaap; van der Graaf, Yolanda; Velthuis, Birgitta K.

    2016-01-01

    INTRODUCTION: Poor leptomeningeal collateral flow is related to worse clinical outcome in acute ischemic stroke, but the factors that determine leptomeningeal collateral patency are largely unknown. We explored the determinants of leptomeningeal collateral flow and assessed their effect on the

  3. Dynamic cerebral autoregulation is unrelated to decrease in external carotid artery blood flow during acute hypotension in healthy young men

    Ogoh, Shigehiko; Sørensen, Henrik; Hirasawa, Ai

    2016-01-01

    men. Both ICA (mean ± SD; by 17 ± 8%, P = 0.005) and ECA (by 37 ± 15%, P 5 s) than for the ECA blood flow (17 ± 5 s; P = 0.019). The ICA blood flow recovery...... from hypoperfusion was delayed with prazosin (17 ± 4 s versus control 9 ± 5 s, P = 0.006), whereas ECA recovery remained unchanged (P = 0.313) despite a similar reduction in mean arterial pressure (−20 ± 4 mmHg versus control −23 ± 7 mmHg, P = 0.148). These findings suggest that α1-receptor blockade...

  4. Fractional flow reserve versus angiography for guidance of PCI in patients with multivessel coronary artery disease (FAME)

    van Nunen, Lokien X; Zimmermann, Frederik M; Tonino, Pim A L

    2015-01-01

    BACKGROUND: In the Fractional Flow Reserve Versus Angiography for Multivessel Evaluation (FAME) study, fractional flow reserve (FFR)-guided percutaneous coronary intervention (PCI) improved outcome compared with angiography-guided PCI for up to 2 years of follow-up. The aim in this study...... was to investigate whether the favourable clinical outcome with the FFR-guided PCI in the FAME study persisted over a 5-year follow-up. METHODS: The FAME study was a multicentre trial done in Belgium, Denmark, Germany, the Netherlands, Sweden, the UK, and the USA. Patients (aged ≥ 18 years) with multivessel coronary...... artery disease were randomly assigned to undergo angiography-guided PCI or FFR-guided PCI. Before randomisation, stenoses requiring PCI were identified on the angiogram. Patients allocated to angiography-guided PCI had revascularisation of all identified stenoses. Patients allocated to FFR-guided PCI had...

  5. Clinical Analysis of 42 Cases of Ocular Ischemic Syndrome

    Jingyi Luo

    2018-01-01

    Full Text Available Ocular ischemic syndrome (OIS is a severe ocular disease caused by ocular hypoperfusion due to stenosis or occlusion of the common or internal carotid arteries. OIS is easily misdiagnosed or undiagnosed given its asymptomatic onset and complicated ocular manifestations. The present study reviewed 42 patients with OIS, including 30 males (71.43%, 29 older patients (69.05%, >61 yrs, and 35 patients (83.33% with two or more systemic diseases. Only 6 patients had ocular symptoms as the initial signs upon visiting the Department of Ophthalmology of three hospitals (the First Affiliated Hospital, Sun Yat-sen University; Zhongshan Ophthalmic Center, Sun Yat-sen University; and the Second Affiliated Hospital, Guangzhou Medical University. The ocular symptoms varied from visual deterioration to periorbital pain. Thirty-seven patients (88.10% complained of constitutional symptoms. Ocular manifestations were diverse and involved both anterior and posterior segments. We reported a case of corneal edema and corneal epithelium erosion in the ipsilateral eye due to internal carotid artery stenosis. As the clinical manifestations of OIS are complex, ophthalmologists must carefully examine patients to avoid a misdiagnosis or a failure to diagnose. The management of OIS requires cooperation with cardiologists and neurologists.

  6. Integration of Quantitative Positron Emission Tomography Absolute Myocardial Blood Flow Measurements in the Clinical Management of Coronary Artery Disease.

    Gewirtz, Henry; Dilsizian, Vasken

    2016-05-31

    In the >40 years since planar myocardial imaging with(43)K-potassium was introduced into clinical research and management of patients with coronary artery disease (CAD), diagnosis and treatment have undergone profound scientific and technological changes. One such innovation is the current state-of-the-art hardware and software for positron emission tomography myocardial perfusion imaging, which has advanced it from a strictly research-oriented modality to a clinically valuable tool. This review traces the evolving role of quantitative positron emission tomography measurements of myocardial blood flow in the evaluation and management of patients with CAD. It presents methodology, currently or soon to be available, that offers a paradigm shift in CAD management. Heretofore, radionuclide myocardial perfusion imaging has been primarily qualitative or at best semiquantitative in nature, assessing regional perfusion in relative terms. Thus, unlike so many facets of modern cardiovascular practice and CAD management, which depend, for example, on absolute values of key parameters such as arterial and left ventricular pressures, serum lipoprotein, and other biomarker levels, the absolute levels of rest and maximal myocardial blood flow have yet to be incorporated into routine clinical practice even in most positron emission tomography centers where the potential to do so exists. Accordingly, this review focuses on potential value added for improving clinical CAD practice by measuring the absolute level of rest and maximal myocardial blood flow. Physiological principles and imaging fundamentals necessary to understand how positron emission tomography makes robust, quantitative measurements of myocardial blood flow possible are highlighted. © 2016 American Heart Association, Inc.

  7. Extremely tortuous coronary arteries - when optical coherence tomography and fractional flow reserve did not help us much

    Miloradović Vladimir

    2018-01-01

    Full Text Available Introduction. Extreme coronary tortuosity may lead to flow alteration resulting in a reduction in coronary pressure distal to the tortuous segment, subsequently leading to ischemia. Therefore the detection of a true cause of ischemia, i.e. whether a fixed stenosis or tortuosity by itself is responsible for its creation, with non-invasive and invasive methods is a real challenge. Case report. We presented a case of a patient with a history of stable angina [Canadian Cardiovascular Society (CCS class II], an abnormal stress test and coronary tortuosity without hemodynamically significant stenosis. Due to suspected linear lesion between the two bends in proximal segment of Right coronary artery (RCA we performed optical coherence tomography (OCT, minimum lumen area (MLA-13.19 mm2 and fractional flow reserve (FFR RCA (0.94. We opted for conservative treatment for stable angina. Conclusion. When tortuosities are associated with atherosclerosis in coronary artery for determination of true cause of ischemia invasive methods can be used, such as OCT and FFR.

  8. Effects of ranolazine on ischemic threshold, coronary sinus blood flow, and myocardial metabolism in coronary artery disease.

    Bagger, J P; Bøtker, H E; Thomassen, A; Nielsen, T T

    1997-07-01

    Cytoprotection or metabolic modulation is a new principle in the treatment of angina pectoris. The effect of ranolazine (a cytoprotective drug) on ischemic threshold, coronary sinus blood flow, and myocardial metabolism was evaluated by means of two pacing sequences in nine male patients with coronary artery disease (CAD) and in eight male controls. Ranolazine was given as an intravenous bolus followed by continuous infusion; the mean total dose was 32.7 mg and 31.7 mg in patients and controls, respectively. Angina pectoris was relieved in two patients after ranolazine but pacing time to pain was unchanged in the remaining patients. Maximal ST depression was lower (p = 0.02), but pacing time to maximal and to 1-mm ST depression remained unchanged after the drug. Ranolazine had no overall influence on coronary sinus blood flow, cardiac oxygen consumption, blood pressure, and heart rate. Cardiac uptake of free fatty acids (FFA) was reduced (p = 0.01), and net uptakes of glucose (p = 0.07) and lactate (p = 0.06) tended to be lower after ranolazine in CAD patients and controls. Ranolazine had no direct influence on cardiac exchange of glutamate, alanine, and citrate or on the arterial concentration of any metabolite. In the present study ranolazine had minimal clinical effects. A decrease in myocardial FFA utilization, however, allows greater myocardial glucose oxidation, which may increase the energy production in relation to oxygen availability.

  9. Quantitation of myocardial blood flow and myocardial flow reserve with {sup 99m}Tc-sestamibi dynamic SPECT/CT to enhance detection of coronary artery disease

    Hsu, Bailing [University of Missouri-Columbia, Nuclear Science and Engineering Institute, Columbia, MO (United States); Chen, Fu-Chung; Chen, Chien-Cheng [Show Chwan Memorial Hospital, Section of Cardiology, Department of Internal Medicine, Changhua (China); Wu, Tao-Cheng [Taipei Veterans General Hospital, Section of Cardiology, Department of Internal Medicine, Taipei (China); Huang, Wen-Sheng [Changhua Christian Hospital, Department of Medical Research and Department of Nuclear Medicine, Changhua (China); Hou, Po-Nien [Chang Bing Show Chwan Memorial Hospital, Department of Nuclear Medicine, Lukong Town, Changhua Shien (China); Hung, Guang-Uei [Chang Bing Show Chwan Memorial Hospital, Department of Nuclear Medicine, Lukong Town, Changhua Shien (China); Central Taiwan University of Science and Technology, Department of Medical Imaging and Radiological Science, Taichung (China); China Medical University, Department of Biomedical Imaging and Radiological Science, Taichung (China)

    2014-12-15

    Conventional dual-head single photon emission computed tomography (SPECT)/CT systems capable of fast dynamic SPECT (DySPECT) imaging have a potential for flow quantitation. This study introduced a new method to quantify myocardial blood flow (MBF) and myocardial flow reserve (MFR) with DySPECT scan and evaluated the diagnostic performance of detecting coronary artery disease (CAD) compared with perfusion using invasive coronary angiography (CAG) as the reference standard. This study included 21 patients with suspected or known CAD who had received DySPECT, ECG-gated SPECT (GSPECT), and CAG (13 with ≥50 % stenosis in any vessel; non-CAD group: 8 with patent arteries or <50 % stenosis). DySPECT and GSPECT scans were performed on a widely used dual-head SPECT/CT scanner. The DySPECT imaging protocol utilized 12-min multiple back-and-forth gantry rotations during injections of {sup 99m}Tc-sestamibi (MIBI) tracer at rest or dipyridamole-stress stages. DySPECT images were reconstructed with full physical corrections and converted to the physical unit of becquerels per milliliter. Stress MBF (SMBF), rest MBF (RMBF), and MFR were quantified by a one-tissue compartment flow model using time-activity curves derived from DySPECT images. Perfusion images were processed for GSPECT scan and interpreted to obtain summed stress score (SSS) and summed difference score (SDS). Receiver-operating characteristic (ROC) analyses were conducted to evaluate the diagnostic performance of flow and perfusion. Using the criteria of ≥50 % stenosis as positive CAD, areas under the ROC curve (AUCs) of flow assessment were overall significantly greater than those of perfusion. For patient-based analysis, AUCs for MFR, SMBF, SSS, and SDS were 0.91 ± 0.07, 0.86 ± 0.09, 0.64 ± 0.12, and 0.59 ± 0.13. For vessel-based analysis, AUCs for MFR, SMBF, SSS, and SDS were 0.81 ± 0.05, 0.76 ± 0.06, 0.62 ± 0.07, and 0.56 ± 0.08, respectively. The preliminary data suggest that MBF quantitation with a

  10. Quantitation of myocardial blood flow and myocardial flow reserve with 99mTc-sestamibi dynamic SPECT/CT to enhance detection of coronary artery disease

    Hsu, Bailing; Chen, Fu-Chung; Chen, Chien-Cheng; Wu, Tao-Cheng; Huang, Wen-Sheng; Hou, Po-Nien; Hung, Guang-Uei

    2014-01-01

    Conventional dual-head single photon emission computed tomography (SPECT)/CT systems capable of fast dynamic SPECT (DySPECT) imaging have a potential for flow quantitation. This study introduced a new method to quantify myocardial blood flow (MBF) and myocardial flow reserve (MFR) with DySPECT scan and evaluated the diagnostic performance of detecting coronary artery disease (CAD) compared with perfusion using invasive coronary angiography (CAG) as the reference standard. This study included 21 patients with suspected or known CAD who had received DySPECT, ECG-gated SPECT (GSPECT), and CAG (13 with ≥50 % stenosis in any vessel; non-CAD group: 8 with patent arteries or 99m Tc-sestamibi (MIBI) tracer at rest or dipyridamole-stress stages. DySPECT images were reconstructed with full physical corrections and converted to the physical unit of becquerels per milliliter. Stress MBF (SMBF), rest MBF (RMBF), and MFR were quantified by a one-tissue compartment flow model using time-activity curves derived from DySPECT images. Perfusion images were processed for GSPECT scan and interpreted to obtain summed stress score (SSS) and summed difference score (SDS). Receiver-operating characteristic (ROC) analyses were conducted to evaluate the diagnostic performance of flow and perfusion. Using the criteria of ≥50 % stenosis as positive CAD, areas under the ROC curve (AUCs) of flow assessment were overall significantly greater than those of perfusion. For patient-based analysis, AUCs for MFR, SMBF, SSS, and SDS were 0.91 ± 0.07, 0.86 ± 0.09, 0.64 ± 0.12, and 0.59 ± 0.13. For vessel-based analysis, AUCs for MFR, SMBF, SSS, and SDS were 0.81 ± 0.05, 0.76 ± 0.06, 0.62 ± 0.07, and 0.56 ± 0.08, respectively. The preliminary data suggest that MBF quantitation with a conventional SPECT/CT system and the flow quantitation method is a clinically effective approach to enhance CAD detection. (orig.)

  11. Influence of isoflurane on the diastolic pressure-flow relationship and critical occlusion pressure during arterial CABG surgery: a randomized controlled trial

    Hinz, Jos?; Mansur, Ashham; Hanekop, Gerd G.; Weyland, Andreas; Popov, Aron F.; Schmitto, Jan D.; Gr?ne, Frank F. G.; Bauer, Martin; Kazmaier, Stephan

    2016-01-01

    The effects of isoflurane on the determinants of blood flow during Coronary Artery Bypass Graft (CABG) surgery are not completely understood. This study characterized the influence of isoflurane on the diastolic Pressure-Flow (P-F) relationship and Critical Occlusion Pressure (COP) during CABG surgery. Twenty patients undergoing CABG surgery were studied. Patients were assigned to an isoflurane or control group. Hemodynamic and flow measurements during CABG surgery were perf...

  12. Influence of oxidative stress on cardiovascular parameters in patients with combined flow of chronic obstructive pulmonary disease and arterial hypertension

    V. G. Deinega

    2013-04-01

    Full Text Available Introduction. It is well known that active forms of oxygen, such as hydrogen peroxide, superoxide anion, hydroxyl radical and others are involved in different pathological conditions, such as cell necrosis, senescence, apoptosis, autophagy, inflammatory responses, remodeling of extracellular matrix and blood vessels, endothelial dysfunction, inactivation of antiproteases, and impaired tissue repair. The pathological increased production of mentioned active forms is called “oxidative stress”. From the literature data, we know that oxidative stress is involved in pathogenesis of arterial hypertension (AH, chronic obstructive pulmonary disease (COPD, atherosclerosis and others. The influence of oxidative stress on cardiovascular disorders in patients with combined flow of COPD and AH is not clearly known. Objective. To study peculiarities and links between parameters of oxidative stress and lesions of heart and vessels in patients with combined flow of COPD and AH. Materials and methods. A total of 101 patients with COPD, AH and with combined flow of COPD and AH were examined. The patients were divided into 3 groups. The first group was formed by patients with AH (n=29 the second group was formed by patients with COPD (n=29, the third group was formed by patients with combined flow of COPD and AH (n=57. Control group was formed from healthy persons of the same age and sex (n=22.All patients underwent spirography, echocardiography, ultrasound measurement of common carotid artery intimal-medial thickness and estimation of endhothelium-dependent vasodilatation. As oxidative stress markers, the levels of oxidative protein modification, spontaneous and iron induced aldehydephenylhydrazone’s (APH, ketondinitrophenylhydrazone’s (KPH and medium size molecules (MSM were measured. Results. Patients with combined flow of COPD and AH had higher levels of spontaneous APH (p<0,01 comparing with first and second group. The levels of spontaneous KPH were

  13. Embolisation of the Gastroduodenal Artery is Not Necessary in the Presence of Reversed Flow Before Yttrium-90 Radioembolisation

    Daghir, Ahmed A., E-mail: ahmeddaghir@doctors.net.uk [Imperial College Healthcare NHS Trust, Department of Radiology (United Kingdom); Gungor, Hatice [Imperial College Healthcare NHS Trust, Department of Oncology (United Kingdom); Haydar, Ali A. [Barts and the London NHS Trust, Department of Radiology (United Kingdom); Wasan, Harpreet S. [Imperial College Healthcare NHS Trust, Department of Oncology (United Kingdom); Tait, Nicholas P. [Imperial College Healthcare NHS Trust, Department of Radiology (United Kingdom)

    2012-08-15

    Introduction: The gastroduodenal artery (GDA) is usually embolised to avoid nontarget dispersal before yttrium-90 (Y{sup 90}) radioembolisation to treat liver metastases. In a minority of patients, there is retrograde flow in the GDA. The purpose of this study was to determine if there is any increased risk from maintaining a patent GDA in patients with reversed flow. Materials and Methods: A retrospective review was performed of all patients undergoing Y{sup 90} radioembolisation at our institution. The incidence of toxicities arising from nontarget radioembolisation by way of the GDA (gastric/duodenal ulceration, gastric/duodenal bleeding, and pancreatitis) and death occurring within 2 months of treatment were compared between the reversed and the antegrade GDA groups. Results: Ninety-two patients underwent preliminary angiography. Reversed GDA flow was found on angiography in 14.1% of cases; the GDA was not embolised in these patients. The GDA was coiled in 55.7% of patients with antegrade GDA flow to prevent inadvertent dispersal of radioembolic material. There was no increased toxicity related to nontarget dispersal by way of the GDA, or increased early mortality, in patients with reversed GDA flow (P > 0.05). Conclusion: In patients with reversed GDA flow, maintenance of a patent GDA before administration of Y{sup 90} radioembolisation does not increase the risk of toxicity from nontarget dispersal. Therapeutic injection, with careful monitoring to identify early vascular stasis, may be safely performed beyond the origin of the patent GDA. A patent GDA with reversed flow provides forward drive for infused particles and may allow alternative access to the hepatic circulation.

  14. [Ocular surface system integrity].

    Safonova, T N; Pateyuk, L S

    2015-01-01

    The interplay of different structures belonging to either the anterior segment of the eye or its accessory visual apparatus, which all share common embryological, anatomical, functional, and physiological features, is discussed. Explanation of such terms, as ocular surface, lacrimal functional unit, and ocular surface system, is provided.

  15. [Descending ocular myopathy].

    de Freitas, M R; Nascimento, O J

    1975-06-01

    The case of a 23 years old female patient, with primary involvement of the extraocular and faringeal muscles without familiar history is reported. Electromyographic and muscular biopsy studies proved the myogenic nature of the process. A clinical comparison between the ocular myopathy and the descending ocular myopathy is made, the authors thinking that both of them would be variants of the same muscle disease.

  16. Epidemiology of Ocular Toxoplasmosis

    Petersen, E.; Kijlstra, A.; Stanford, M.

    2012-01-01

    Retinal infection with Toxoplasma gondii is the most important cause of posterior uveitis, whereby prevalence and incidence of ocular symptoms after infection depend on socio-economic factors and the circulating parasite genotypes. Ocular toxoplasmosis is more common in South America, Central

  17. Influence of model boundary conditions on blood flow patterns in a patient specific stenotic right coronary artery.

    Liu, Biyue; Zheng, Jie; Bach, Richard; Tang, Dalin

    2015-01-01

    In literature, the effect of the inflow boundary condition was investigated by examining the impact of the waveform and the shape of the spatial profile of the inlet velocity on the cardiac hemodynamics. However, not much work has been reported on comparing the effect of the different combinations of the inlet/outlet boundary conditions on the quantification of the pressure field and flow distribution patterns in stenotic right coronary arteries. Non-Newtonian models were used to simulate blood flow in a patient-specific stenotic right coronary artery and investigate the influence of different boundary conditions on the phasic variation and the spatial distribution patterns of blood flow. The 3D geometry of a diseased artery segment was reconstructed from a series of IVUS slices. Five different combinations of the inlet and the outlet boundary conditions were tested and compared. The temporal distribution patterns and the magnitudes of the velocity, the wall shear stress (WSS), the pressure, the pressure drop (PD), and the spatial gradient of wall pressure (WPG) were different when boundary conditions were imposed using different pressure/velocity combinations at inlet/outlet. The maximum velocity magnitude in a cardiac cycle at the center of the inlet from models with imposed inlet pressure conditions was about 29% lower than that from models using fully developed inlet velocity data. Due to the fact that models with imposed pressure conditions led to blunt velocity profile, the maximum wall shear stress at inlet in a cardiac cycle from models with imposed inlet pressure conditions was about 29% higher than that from models with imposed inlet velocity boundary conditions. When the inlet boundary was imposed by a velocity waveform, the models with different outlet boundary conditions resulted in different temporal distribution patterns and magnitudes of the phasic variation of pressure. On the other hand, the type of different boundary conditions imposed at the

  18. Doppler sonographic evaluation of ophthalmic arterial flow pattern in hypertensive patients

    Ryu, Dae Sik; Kim, Young Goo

    1994-01-01

    To compare the Doppler velocity waveform pattern of ophthalmic artery of hypertensive patients with that of normotensive subjects. Doppler velocity waveform was obtained from ophthalmic artery in 45 hypertensive patients and 60 normotensive subjects. Both hypertensives and normotensive subjects were classified according to age into those younger than and those older than 45 years. Doppler indices(pulsatility index(PI), resistance index(RI), the first systolic peak/the second systolic peak(S1/S2), the first systolic peak/diastolic peak(S1/D)) measured in hypertensive patients were compared with normotensive subjects. Among the various doppler indices, only S1/S2 showed significant difference(P < 0.05) between the hypertensive patients and normotensive subjects younger than 45 years. Doppler velocity waveform of hypertensive patients older than 45 years showed no significant difference from that of normotensive subjects with corresponding age. Doppler velocity waveform of ophthalmic artery in hypertensive patients younger than 45 years shows pattern with S2 higher than that of normotensive subjects. High S2 component(reflective-wave) may represent increased vascular impedance due to vasococonstriction of retinal arterioles in hypertensive patients

  19. Myocardial blood flow reserve is impaired in patients with aortic valve calcification and unobstructed epicardial coronary arteries.

    Nel, Karen; Nam, Michael C Y; Anstey, Chris; Boos, Christopher J; Carlton, Edward; Senior, Roxy; Kaski, Juan Carlos; Khattab, Ahmed; Shamley, Delva; Byrne, Christopher D; Stanton, Tony; Greaves, Kim

    2017-12-01

    Although calcific aortic valve disease (CAVD) is associated with coronary atherosclerosis, it is not known whether early CAVD is associated with coronary microcirculatory dysfunction (CMD). We sought to investigate the relationship between myocardial blood flow reserve (MBFR) - a measure of CMD, and early CAVD in the absence of obstructive epicardial coronary artery disease. We also determined whether this relationship was independent of coronary artery disease (CAD) and hs-CRP, a marker of systemic inflammation. 183 patients with chest pain and unobstructed coronary arteries were studied. Aortic valve calcification score (AVCS), coronary total plaque length (TPL), and coronary calcium score were quantified from multislice CT. MBFR was assessed using vasodilator myocardial contrast echocardiography. Hs-CRP was measured from venous blood using a particle-enhanced immunoassay. Mean (±SD) participant age was 59.8 (9.6) years. Mean AVCS was 68 (258) AU, TPL was 15.6 (22.2) mm, and median coronary calcification score was 43.5AU. Mean MBFR was 2.20 (0.52). Mean hs-CRP was 2.52 (3.86) mg/l. Multivariable linear regression modelling incorporating demographics, coronary plaque characteristics, MBFR, and inflammatory markers, demonstrated that age (β=0.05, 95% CI: 0.02, 0.08, P=0.007), hs-CRP (β=0.09, CI: 0.02, 0.16, P=0.010) and diabetes (β=1.03, CI: 0.08, 1.98, P=0.033), were positively associated with AVCS. MBFR (β=-0.87, CI: -1.44, -0.30, P=0.003), BMI (β=-0.11, CI: -0.21, -0.01, P=0.033), and LDL (β=-0.32, CI: -0.61, -0.03, P=0.029) were negatively associated with AVCS. TPL and coronary calcium score were not independently associated with AVCS when included in the regression model. Coronary microvascular function as determined by measurement of myocardial blood flow reserve is independently associated with early CAVD. This effect is independent of the presence of coronary artery disease and also systemic inflammation. Copyright © 2017 Elsevier B.V. All rights

  20. The role of disturbed blood flow in the development of pulmonary arterial hypertension: lessons from preclinical animal models.

    Dickinson, Michael G; Bartelds, Beatrijs; Borgdorff, Marinus A J; Berger, Rolf M F

    2013-07-01

    Pulmonary arterial hypertension (PAH) is a progressive pulmonary vasoproliferative disorder characterized by the development of unique neointimal lesions, including concentric laminar intima fibrosis and plexiform lesions. Although the histomorphology of neointimal lesions is well described, the pathogenesis of PAH and neointimal development is largely unknown. After three decades of PAH pathobiology research the focus has shifted from vasoconstriction towards a mechanism of cancer-like angioproliferation. In this concept the role of disturbed blood flow is seen as an important trigger in the development of vascular remodeling. For instance, in PAH associated with congenital heart disease, increased pulmonary blood flow (i.e., systemic-to-pulmonary shunt) is an essential trigger for the occurrence of neointimal lesions and PAH development. Still, questions remain about the exact role of these blood flow characteristics in disease progression. PAH animal models are important for obtaining insight in new pathobiological processes and therapeutical targets. However, as for any preclinical model the pathophysiological mechanism and clinical course has to be comparable to the human disease that it mimics. This means that animal models mimicking human PAH ideally are characterized by: a hit recognized in human disease (e.g., altered pulmonary blood flow), specific vascular remodeling resembling human neointimal lesions, and disease progression that leads to right ventriclular dysfunction and death. A review that underlines the current knowledge of PAH due to disturbed flow is still lacking. In this review we will summarize the current knowledge obtained from PAH animal models associated with disturbed pulmonary blood flow and address questions for future treatment strategies for PAH.

  1. A New Flow Control Technique Using Diluted Epinephrine in the N-butyl-2-cyanoacrylate Embolization of Visceral Artery Pseudoaneurysms Secondary to Chronic Pancreatitis

    Morishita, Hiroyuki, E-mail: hmorif@koto.kpu-m.ac.jp [Japan Red Cross Kyoto Daiichi Hospital, Department of Diagnostic Radiology (Japan); Yamagami, Takuji [Kyoto Prefectural University of Medicine, Department of Radiology, Graduate School of Medical Science (Japan); Takeuchi, Yoshito [National Cancer Center, Division of Diagnostic Radiology (Japan); Matsumoto, Tomohiro; Asai, Shunsuke; Masui, Koji [Japan Red Cross Kyoto Daiichi Hospital, Department of Diagnostic Radiology (Japan); Sato, Hideki [Japan Red Cross Kyoto Daiichi Hospital, Department of Gastroenterology (Japan); Taniguchi, Fumihiro [Japan Red Cross Kyoto Daiichi Hospital, Department of Surgery (Japan); Sato, Osamu [Japan Red Cross Kyoto Daiichi Hospital, Department of Diagnostic Radiology (Japan); Nishimura, Tsunehiko [Kyoto Prefectural University of Medicine, Department of Radiology, Graduate School of Medical Science (Japan)

    2012-08-15

    Although n-butyl-2-cyanoacrylate (NBCA) has been used as an effective liquid embolization material, its indication for pseudoaneurysms has seemingly been limited because of the technical difficulties of using NBCA, such as reflux to the parent artery and causing significant infarction. Thus, considerable skill in using NBCA or a device to control blood flow during its polymerization is required to achieve embolization without severe complications. We report our new technique for controlling blood flow using diluted epinephrine in transcatheter arterial NBCA embolization of five pseudoaneurysms in four cases secondary to hemosuccus pancreaticus.

  2. Myocardial blood flow quantification for evaluation of coronary artery disease by positron emission tomography, cardiac magnetic resonance imaging, and computed tomography.

    Waller, Alfonso H; Blankstein, Ron; Kwong, Raymond Y; Di Carli, Marcelo F

    2014-05-01

    The noninvasive detection of the presence and functional significance of coronary artery stenosis is important in the diagnosis, risk assessment, and management of patients with known or suspected coronary artery disease. Quantitative assessment of myocardial perfusion can provide an objective and reproducible estimate of myocardial ischemia and risk prediction. Positron emission tomography, cardiac magnetic resonance, and cardiac computed tomography perfusion are modalities capable of measuring myocardial blood flow and coronary flow reserve. In this review, we will discuss the technical aspects of quantitative myocardial perfusion imaging with positron emission tomography, cardiac magnetic resonance imaging, and computed tomography, and its emerging clinical applications.

  3. Nonenhanced magnetic resonance angiography (MRA) of the calf arteries at 3 Tesla: intraindividual comparison of 3D flow-dependent subtractive MRA and 2D flow-independent non-subtractive MRA.

    Knobloch, Gesine; Lauff, Marie-Teres; Hirsch, Sebastian; Schwenke, Carsten; Hamm, Bernd; Wagner, Moritz

    2016-12-01

    To prospectively compare 3D flow-dependent subtractive MRA vs. 2D flow-independent non-subtractive MRA for assessment of the calf arteries at 3 Tesla. Forty-two patients with peripheral arterial occlusive disease underwent nonenhanced MRA of calf arteries at 3 Tesla with 3D flow-dependent subtractive MRA (fast spin echo sequence; 3D-FSE-MRA) and 2D flow-independent non-subtractive MRA (balanced steady-state-free-precession sequence; 2D-bSSFP-MRA). Moreover, all patients underwent contrast-enhanced MRA (CE-MRA) as standard-of-reference. Two readers performed a per-segment evaluation for image quality (4 = excellent to 0 = non-diagnostic) and severity of stenosis. Image quality scores of 2D-bSSFP-MRA were significantly higher compared to 3D-FSE-MRA (medians across readers: 4 vs. 3; p Tesla with significantly higher image quality and diagnostic accuracy compared to 3D flow-dependent subtractive MRA (3D-FSE-MRA). • 2D flow-independent non-subtractive MRA (2D-bSSFP-MRA) is a robust NE-MRA technique at 3T • 2D-bSSFP-MRA outperforms 3D flow-dependent subtractive MRA (3D-FSE-MRA) as NE-MRA of calf arteries • 2D-bSSFP-MRA is a promising alternative to CE-MRA for calf PAOD evaluation.

  4. A study of coronary artery rotational motion with dense scale-space optical flow in intravascular ultrasound

    Danilouchkine, M G; Mastik, F; Steen, A F W van der [Department of Biomedical Engineering, Erasmus Medical Center, Ee2302, PO Box 2040, 3000 CA, Rotterdam (Netherlands)], E-mail: m.danilouchkine@ErasmusMC.nl, E-mail: f.mastik@ErasmusMC.nl, E-mail: a.vandersteen@ErasmusMC.nl

    2009-03-21

    This paper describes a novel method for estimating tissue motion in two-dimensional intravascular ultrasound (IVUS) images of a coronary artery. It is based on the classical Lukas-Kanade (LK) algorithm for optical flow (OF). The OF vector field quantifies the amount of misalignment between two consecutive frames in a sequence of images. From the theoretical standpoint, two fundamental improvements are proposed in this paper. First, using a simplified representation of the vessel wall as a medium with randomly distributed scatterers, it was shown that the OF equation satisfies the integral brightness conservation law. Second, a scale-space embedding for the OF equation was derived under the assumption of spatial consistency in IVUS acquisitions. The spatial coherence is equivalent to a locally affine motion model. The latter effectively captures and appropriately describes a complex deformation pattern of the coronary vessel wall under the varying physiological conditions (i.e. pulsatile blood pressure). The accuracy of OF tracking was estimated on the tissue-mimicking phantoms subjected to the controlled amount of angular deviation. Moreover, the performance of the classical LK and proposed approach was compared using the simulated IVUS images with an atherosclerotic lesion. The experimental results showed robust and reliable performance of up to 5{sup 0} of rotation, which is within the plausible range of circumferential displacement of the coronary arteries. Subsequently, the algorithm was used to analyze vessel wall motion in 18 IVUS pullbacks from 16 patients. The in vivo experiments revealed that the motion of coronary arteries is primarily determined by the cardiac contraction.

  5. Modeling of the blood flow in the lower extremities for dynamic diffuse optical tomography of peripheral artery disease

    Marone, A.; Hoi, J. W.; Khalil, M. A.; Kim, H. K.; Shrikhande, G.; Dayal, R.; Hielscher, A. H.

    2015-07-01

    Peripheral Arterial Disease (PAD) is caused by a reduction of the internal diameters of the arteries in the upper or lower extremities mainly due to atherosclerosis. If not treated, its worsening may led to a complete occlusion, causing the death of the cells lacking proper blood supply, followed by gangrene that may require chirurgical amputation. We have recently performed a clinical study in which good sensitivities and specificities were achieved with dynamic diffuse optical tomography. To gain a better understanding of the physiological foundations of many of the observed effects, we started to develop a mathematical model for PAD. The model presented in this work is based on a multi-compartment Windkessel model, where the vasculature in the leg and foot is represented by resistors and capacitors, the blood pressure with a voltage drop, and the blood flow with a current. Unlike existing models, the dynamics induced by a thigh-pressure-cuff inflation and deflation during the measurements are taken into consideration. This is achieved by dynamically varying the resistances of the large veins and arteries. By including the effects of the thigh-pressure cuff, we were able to explain many of the effects observed during our dynamic DOT measurements, including the hemodynamics of oxy- and deoxy-hemoglobin concentration changes. The model was implemented in MATLAB and the simulations were normalized and compared with the blood perfusion obtained from healthy, PAD and diabetic patients. Our preliminary results show that in unhealthy patients the total system resistance is sensibly higher than in healthy patients.

  6. Arterial aging and arterial disease : interplay between central hemodynamics, cardiac work, and organ flow-implications for CKD and cardiovascular disease

    London, Gerard; Covic, Adrian; Goldsmith, David; Wiecek, Andrzej; Suleymanlar, Gultekin; Ortiz, Alberto; Massy, Ziad; Lindholm, Bengt; Martinez-Castelao, Alberto; Fliser, Danilo; Agarwal, Rajiv; Jager, Kitty J.; Dekker, Friedo W.; Blankestijn, Peter J.; Zoccali, Carmine

    Cardiovascular disease is an important cause of morbidity and mortality in patients with chronic kidney disease (CKD) and end-stage renal disease (ESRD). All epidemiological studies have clearly shown that accelerated arterial and cardiac aging is characteristic of these populations. Arterial

  7. Functional Relevance of Coronary Artery Disease by Cardiac Magnetic Resonance and Cardiac Computed Tomography: Myocardial Perfusion and Fractional Flow Reserve

    Gianluca Pontone

    2015-01-01

    Full Text Available Coronary artery disease (CAD is one of the leading causes of morbidity and mortality and it is responsible for an increasing resource burden. The identification of patients at high risk for adverse events is crucial to select those who will receive the greatest benefit from revascularization. To this aim, several non-invasive functional imaging modalities are usually used as gatekeeper to invasive coronary angiography, but the diagnostic yield of elective invasive coronary angiography remains unfortunately low. Stress myocardial perfusion imaging by cardiac magnetic resonance (stress-CMR has emerged as an accurate technique for diagnosis and prognostic stratification of the patients with known or suspected CAD thanks to high spatial and temporal resolution, absence of ionizing radiation, and the multiparametric value including the assessment of cardiac anatomy, function, and viability. On the other side, cardiac computed tomography (CCT has emerged as unique technique providing coronary arteries anatomy and more recently, due to the introduction of stress-CCT and noninvasive fractional flow reserve (FFR-CT, functional relevance of CAD in a single shot scan. The current review evaluates the technical aspects and clinical experience of stress-CMR and CCT in the evaluation of functional relevance of CAD discussing the strength and weakness of each approach.

  8. Hemoglobin, hematocrit, and changes in cerebral blood flow: the Second Manifestations of ARTerial disease-Magnetic Resonance study.

    van der Veen, Pieternella H; Muller, Majon; Vincken, Koen L; Westerink, Jan; Mali, Willem P T M; van der Graaf, Yolanda; Geerlings, Mirjam I

    2015-03-01

    Hemoglobin and hematocrit are important determinants of blood viscosity and arterial oxygen content and may therefore influence cerebral blood flow (CBF). We examined cross-sectional and prospective associations of hemoglobin and hematocrit with CBF in 569 patients with manifest arterial disease (mean age 57 ± 10 years) with available data on magnetic resonance angiography to measure parenchymal CBF. Mean (SD) parenchymal CBF at baseline was 52.3 (9.8) mL/min/100 mL and decreased with 1.5 (11.0) mL/min/100 mL after on average 3.9 years of follow-up. Linear regression analyses showed that greater hemoglobin and hematocrit values were associated with lower baseline parenchymal CBF and more decline in parenchymal CBF over time, independent of cardiovascular risk factors, use of antiplatelet drugs, anticoagulants, or diuretics, and brain measures: adjusted mean differences (95% confidence interval [CI]) in decline in parenchymal CBF between patients in the lower and upper quartiles of hemoglobin and hematocrit were -2.48 (95% CI -3.70 to -1.25) and -3.69 (95% CI -5.45 to -1.94) mL/min/100 mL. Higher hemoglobin and hematocrit were associated with lower baseline parenchymal CBF and a greater decline in parenchymal CBF over time, possibly as a result of physiological compensating mechanisms. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. Is the measurement of inferior thyroid artery blood flow velocity by color-flow Doppler ultrasonography useful for differential diagnosis between gestational transient thyrotoxicosis and Graves' disease? A prospective study.

    Zuhur, Sayid Shafi; Ozel, Alper; Velet, Selvinaz; Buğdacı, Mehmet Sait; Cil, Esra; Altuntas, Yüksel

    2012-01-01

    To determine the role of peak systolic velocity, end-diastolic velocity and resistance indices of both the right and left inferior thyroid arteries measured by color-flow Doppler ultrasonography for a differential diagnosis between gestational transient thyrotoxicosis and Graves' disease during pregnancy. The right and left inferior thyroid artery-peak systolic velocity, end-diastolic velocity and resistance indices of 96 patients with thyrotoxicosis (41 with gestational transient thyrotoxicosis, 31 age-matched pregnant patients with Graves' disease and 24 age- and sex-matched non-pregnant patients with Graves' disease) and 25 age and sex-matched healthy euthyroid subjects were assessed with color-flow Doppler ultrasonography. The right and left inferior thyroid artery-peak systolic and end-diastolic velocities in patients with gestational transient thyrotoxicosis were found to be significantly lower than those of pregnant patients with Graves' disease and higher than those of healthy euthyroid subjects. However, the right and left inferior thyroid artery peak systolic and end-diastolic velocities in pregnant patients with Graves' disease were significantly lower than those of non-pregnant patients with Graves' disease. The right and left inferior thyroid artery peak systolic and end-diastolic velocities were positively correlated with TSH-receptor antibody levels. We found an overlap between the inferior thyroid artery-blood flow velocities in a considerable number of patients with gestational transient thyrotoxicosis and pregnant patients with Graves' disease. This study suggests that the measurement of inferior thyroid artery-blood flow velocities with color-flow Doppler ultrasonography does not have sufficient sensitivity and specificity to be recommended as an initial diagnostic test for a differential diagnosis between gestational transient thyrotoxicosis and Graves' disease during pregnancy.

  10. Peripheral Artery Disease and Continuous Flow Left Ventricle Assist Device: An Engaging Complement Analysis May Help to Guide Treatment.

    Falletta, Calogero; Pasta, Salvatore; Raffa, Giuseppe Maria; Crinò, Francesca; Sciacca, Sergio; Clemenza, Francesco

    2018-02-13

    Use of continuous flow left ventricle assist device (CF-LVAD) in advanced heart failure (HF) patients results in clinically relevant improvements in survival, functional capacity, and quality of life. Peripheral artery disease (PAD) can occur in patients with CF-LVAD due to the high rate of concomitance between risk factors for atherosclerosis and HF. Diagnosis of PAD can be difficult in the specific setting of a patient supported by this kind of device because of the marked alteration in waveform morphology and velocity created by the artificial physiology of an LVAD. We report the case of a 53-year-old man with HF secondary to ischemic cardiomyopathy supported by the HeartWare HVAD as bridge to transplant, who after the implant developed symptoms suggestive of PAD. We describe additional computational flow analysis for the study of PAD-related hemodynamic disturbances induced by a CF-LVAD. Flow simulations enhance the information of clinical image data, and may have an application in clinical investigations of the risk of hemodynamic disturbances induced by LVAD implantation. © 2018 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

  11. Measurement of regional pulmonary blood volume in patients with increased pulmonary blood flow or pulmonary arterial hypertension

    Wollmer, P.; Rozcovek, A.; Rhodes, C.G.; Allan, R.M.; Maseri, A.

    1984-01-01

    The effects of chronic increase in pulmonary blood flow and chronic pulmonary hypertension on regional pulmonary blood volume was measured in two groups of patients. One group of patients had intracardiac, left-to-right shunts without appreciable pulmonary hypertension, and the other consisted of patients with Eisenmenger's syndrome or primary pulmonary hypertension, i.e. patients with normal or reduced blood flow and severe pulmonary hypertension. A technique based on positron tomography was used to measure lung density (by transmission scanning) and regional pulmonary blood volume (after inhalation of /sup 11/CO). The distribution of pulmonary blood volume was more uniform in patients with chronic increase in pulmonary blood flow than in normal subjects. There were also indications of an absolute increase in intrapulmonary blood volume by about 15%. In patients with chronic pulmonary arterial hypertension, the distribution of pulmonary blood volume was also abnormally uniform. There was, however, no indication that overall intrapulmonary blood volume was substantially different from normal subjects. The abnormally uniform distribution of pulmonary blood volume can be explained by recruitment and/or dilatation of vascular beds. Intrapulmonary blood volume appears to be increased in patients with intracardiac, left-to-right shunts. With the development of pulmonary hypertension, intrapulmonary blood volume falls, which may be explained by reactive changes in the vasculature and/or obliteration of capillaries

  12. Flow velocity and volume measurement of superior and inferior mesenteric artery with cine phase contrast magnetic resonance imaging

    Naganawa, Shinji; Cooper, T.G.; Jenner, G.; Potchen, E.J.; Ishigaki, Takeo.

    1994-01-01

    The flow velocity and volume of the superior and inferior mesenteric arteries (SMA, IMA) were measured with cine phase contrast magnetic resonance (MR) imaging in five healthy volunteers. Each volunteer was first measured in a fasting state, and then one, two, and three hours after a meal. The average SMA flow volume of the volunteers was 230.3±46.8 ml/min (mean±standard error) during the fasting state, and 714.7±207.7 ml/min, 339.2±85.7 ml/min, and 263.8±21.0 ml/min, respectively, at one, two, and three hours postmeal. The increase at one hour postmeal was statistically significant (p<0.05). The corresponding flow measurements in the IMA were 63.1±11.2 ml/min, 67.6±11.2 ml/min, 57.9±8.6 ml/min, and 53.2±6.8 ml/min. These values do not represent a statistically significant flow volume change in the IMA. In all volunteers, the SMA volumetric flow increased the most one hour after the food challenge (72-400% relative to baseline). Diastolic velocity in the SMA increased significantly one hour postmeal, but systolic velocity did not change significantly. The IMA did not demonstrate a significant change in either systolic or diastolic velocity. The difference between the SMA and IMA in the way of reacting against the food challenge is thought to represent the difference between the requirements of small and large intestine for blood supply after the food challenge. These data demonstrate the possibility of this modality for the assessment of conditions such as chronic mesenteric ischemia. (author)

  13. Myocardial Blood Flow and Flow Reserve in Proximal and Mid-to-Distal Lesions of Left Anterior Descending Artery Measured By N-13 Ammonia PET/CT

    Cho, Sanggeon; Kim, Ju Han; Cho, Jae Young; Kim, Hyeon Sik; Bom, Heeseung

    2013-01-01

    The purpose of this study is to compare the myocardial blood flow (MBF) and flow reserve (MFR) between proximal and mid-to-distal lesions of the left anterior descending artery (pLAD and mdLAD, respectively) using N-13 ammonia positron emission tomography/computed tomography (PET/CT). Subjects were 11 patients (six men and five women, mean age 64.5 years) with known coronary artery disease (CAD) involving LAD studied by N-13 ammonia PET/CT. They were divided into two groups by the location of stenotic lesions, i.e. pLAD versus mdLAD. Global and regional MBF and MFR were measured and compared. Characteristics of perfusion defects including the number of involved segments, basal area involvement, location, size, and shape were also compared between the two groups. The regional MFR in mid-anterior segment was significantly lower in pLAD group (1.80±0.35 vs 2.76±1.13 for pLAD and mdLAD groups, respectively, p=0.034), while global MFR was not different (2.10±1.10 vs 2.34±0.84). Both stress and rest MBF in LAD territories were not different in both groups. The size of the perfusion defects were significantly larger in pLAD group (44.0±11.5 % vs 21-1±15.8 %, p=0.041). Other characteristics such as location, basal area involvement, and shape were not significantly different between two groups. Conclusions The proximal lesion makes lower MFR in the mid-anterior segment and larger perfusion defect in the LAD territory but comparable MBF compared with mdLAD lesion

  14. Renal blood flow regulation and arterial pressure fluctuations: a case study in nonlinear dynamics

    Holstein-Rathlou, N H; Marsh, D J

    1994-01-01

    in which the kidney is obliged to operate. Were it not for renal blood flow autoregulation, it would be difficult to regulate renal excretory processes so as to maintain whole body variables within narrow bounds. Autoregulation is the noise filter on which other renal processes depend for maintaining...... a relatively noise-free environment in which to work. Because of the time-varying nature of the blood pressure, we have concentrated in this review on the now substantial body of work on the dynamics of renal blood flow regulation and the underlying mechanisms. Renal vascular control mechanisms are not simply....... The significance of deterministic chaos in the context of renal blood flow regulation is that the system regulating blood flow undergoes a physical change to a different dynamical state, and because the change is deterministic, there is every expectation that the critical change will yield itself to experimental...

  15. the factors that affect the free flow speed on an arterial in ilorin, nigeria

    user

    lower average free flow speed of commercial saloon cars on wet pavement than on dry pavement, with 12% percentage ... average space mean speed in a low volume traffic stream when ..... travel way width and number of traffic control units.

  16. Endothelial shear stress estimation in the human carotid artery based on Womersley versus Poiseuille flow

    Schwarz, Janina C. V.; Duivenvoorden, Raphaël; Nederveen, Aart J.; Stroes, Erik S. G.; VanBavel, Ed

    2015-01-01

    Endothelial shear stress (ESS) dynamics are a major determinant of atherosclerosis development. The frequently used Poiseuille method to estimate ESS dynamics has important limitations. Therefore, we investigated whether Womersley flow may provide a better alternative for estimation of ESS while

  17. Relationship between regional myocardial blood flow and thallium-201 distribution in the presence of coronary artery stenosis and dipyridamole-induced vasodilation

    Mays, A.E. Jr.; Cobb, F.R.

    1984-01-01

    This study assesses the relationship between the distribution of thallium-201 and myocardial blood flow during coronary vasodilation induced by intravenous dipyridamole in canine models of partial and complete coronary artery stenosis. 10 dogs were chronically instrumented with catheters in the left atrium and aorta and with a balloon occluder and electromagnetic flow probe on the proximal left circumflex coronary artery. Regional myocardial blood flow was measured during control conditions with radioisotope-labeled microspheres, and the phasic reactive hyperemic response to a 20-s transient occlusion was then recorded. Dipyridamole was then infused intravenously until phasic coronary blood flow increased to match peak hyperemic values. The left circumflex coronary artery was either partially occluded to reduce phasic blood flow to control values (group 1) or it was completely occluded (group 2), and thallium-201 and a second microsphere label were injected. 5 min later, the animals were sacrificed, the left ventricle was sectioned into 1-2-g samples, and thallium-201 activity and regional myocardial blood flow were measured. Curvilinear regression analyses between thallium-201 localization and myocardial blood flow during dipyridamole infusion demonstrated a slightly better fit to a second- as compared with a first-order model, indicating a slight roll-off of thallium activity as myocardial blood flow increases. During the dipyridamole infusion, the increases in phasic blood flow, the distributions of regional myocardial blood flow, and the relationships between thallium-201 localization and regional blood flow were comparable to values previously observed in exercising dogs with similar occlusions. These data provide basic validation that supports the use of intravenous dipyridamole and thallium-201 as an alternative to exercise stress and thallium-201 for evaluating the effects of coronary occlusive lesions on the distribution of regional myocardial blood flow

  18. Automated segmentation of blood-flow regions in large thoracic arteries using 3D-cine PC-MRI measurements.

    van Pelt, Roy; Nguyen, Huy; ter Haar Romeny, Bart; Vilanova, Anna

    2012-03-01

    Quantitative analysis of vascular blood flow, acquired by phase-contrast MRI, requires accurate segmentation of the vessel lumen. In clinical practice, 2D-cine velocity-encoded slices are inspected, and the lumen is segmented manually. However, segmentation of time-resolved volumetric blood-flow measurements is a tedious and time-consuming task requiring automation. Automated segmentation of large thoracic arteries, based solely on the 3D-cine phase-contrast MRI (PC-MRI) blood-flow data, was done. An active surface model, which is fast and topologically stable, was used. The active surface model requires an initial surface, approximating the desired segmentation. A method to generate this surface was developed based on a voxel-wise temporal maximum of blood-flow velocities. The active surface model balances forces, based on the surface structure and image features derived from the blood-flow data. The segmentation results were validated using volunteer studies, including time-resolved 3D and 2D blood-flow data. The segmented surface was intersected with a velocity-encoded PC-MRI slice, resulting in a cross-sectional contour of the lumen. These cross-sections were compared to reference contours that were manually delineated on high-resolution 2D-cine slices. The automated approach closely approximates the manual blood-flow segmentations, with error distances on the order of the voxel size. The initial surface provides a close approximation of the desired luminal geometry. This improves the convergence time of the active surface and facilitates parametrization. An active surface approach for vessel lumen segmentation was developed, suitable for quantitative analysis of 3D-cine PC-MRI blood-flow data. As opposed to prior thresholding and level-set approaches, the active surface model is topologically stable. A method to generate an initial approximate surface was developed, and various features that influence the segmentation model were evaluated. The active surface

  19. Different Bleeding Patterns with the Use of Levonorgestrel Intrauterine System: Are They Associated with Changes in Uterine Artery Blood Flow?

    Carlo Bastianelli

    2014-01-01

    Full Text Available Objective. Evaluate if different bleeding patterns associated with the use of the levonorgestrel intrauterine system (LNG-IUS are associated with different uterine and endometrial vascularization patterns, as evidenced by ultrasound power Doppler analysis. Methodology. A longitudinal study, with each subject acting as its own control was conducted between January 2010 and December 2012. Healthy volunteers with a history of heavy but cyclic and regular menstrual cycles were enrolled in the study. Ultrasonographic examination was performed before and after six months of LNG-IUS placement: uterine volume, endometrial thickness, and subendometrial and myometrial Doppler blood flow patterns have been evaluated. Results. A total of 32 women were enrolled out of 186 initially screened. At six months of follow-up, all subjects showed a reduction in menstrual blood loss; for analysis, they were retrospectively divided into 3 groups: normal cycling women (Group I, amenorrheic women (Group II, and women with prolonged bleedings (Group III. Intergroup analysis documented a statistically significant difference in endometrial thickness among the three groups; in addition, mean pulsatility index (PI and resistance index (RI in the spiral arteries were significantly lower in Group I and Group III compared to Group II. This difference persisted also when comparing—within subjects of Group III—mean PI and RI mean values before and after insertion. Conclusions. The LNG-IUS not only altered endometrial thickness, but—in women with prolonged bleedings—also significantly changed uterine artery blood flow. Further studies are needed to confirm these results and enable gynecologists to properly counsel women, improving initial continuation rates.

  20. Assessment of coronary flow reserve by sestamibi imaging in patients with typical chest pain and normal coronary arteries

    Storto, Giovanni; Sorrentino, Anna R.; Pellegrino, Teresa; Liuzzi, Raffaele; Cuocolo, Alberto; Petretta, Mario

    2007-01-01

    We assessed coronary flow reserve (CFR) by sestamibi imaging in patients with typical chest pain, positive exercise stress test and normal coronary vessels. Thirty-five patients with typical chest pain and normal angiogram and 12 control subjects with atypical chest pain underwent dipyridamole/rest 99m Tc-sestamibi imaging. Myocardial blood flow (MBF) was estimated by measuring first transit counts in the pulmonary artery and myocardial counts from SPECT images. Estimated CFR was expressed as the ratio of stress to rest MBF. Rest MBF and CFR were corrected for rate-pressure product (RPP) and expressed as normalised MBF (MBF n ) and normalised CFR (CFR n ). Coronary vascular resistances (CVR) were calculated as the ratio between mean arterial pressure and estimated MBF. At rest, estimated MBF and MBF n were lower in controls than in patients (0.98 ± 0.4 vs 1.30 ± 0.3 counts/pixel/s and 1.14 ± 0.5 vs 1.64 ± 0.6 counts/pixel/s, respectively, both p n was still higher in controls than in patients (2.1 ± 0.5 vs 1.29 ± 0.5, p < 0.0001). At baseline, CVR values were lower (p < 0.01) in patients than in controls. Dipyridamole-induced changes in CVR were greater (p < 0.0001) in controls (-63%) than in patients (-35%). In the overall study population, a significant correlation between dipyridamole-induced changes in CVR and CFR was observed (r = -0.88, p < 0.0001). SPECT might represent a useful non-invasive method for assessing coronary vascular function in patients with angina and a normal coronary angiogram. (orig.)

  1. FLAIR vascular hyperintensities and 4D MR angiograms for the estimation of collateral blood flow in anterior cerebral artery ischemia.

    Matthias Gawlitza

    Full Text Available To assess FLAIR vascular hyperintensities (FVH and dynamic (4D angiograms derived from perfusion raw data as proposed magnetic resonance (MR imaging markers of leptomeningeal collateral circulation in patients with ischemia in the territory of the anterior cerebral artery (ACA.Forty patients from two tertiary care university hospitals were included. Infarct volumes and perfusion deficits were manually measured on DWI images and TTP maps, respectively. FVH and collateral flow on 4D MR angiograms were assessed and graded as previously specified.Forty-one hemispheres were affected. Mean DWI lesion volume was 8.2 (± 13.9; range 0-76.9 ml, mean TTP lesion volume was 24.5 (± 17.2, range 0-76.7 ml. FVH were observed in 26/41 (63.4% hemispheres. Significant correlations were detected between FVH and TTP lesion volume (ρ = 0.4; P<0.01 absolute (ρ = 0.37; P<0.05 and relative mismatch volume (ρ = 0.35; P<0.05. The modified ASITN/SIR score correlated inversely with DWI lesion volume (ρ = -0.58; P<0.01 and positively with relative mismatch (ρ = 0.29; P< 0.05. ANOVA of the ASITN/SIR score revealed significant inter-group differences for DWI (P<0.001 and TTP lesion volumes (P<0.05. No correlation was observed between FVH scores and modified ASITH/SIR scores (ρ = -0.16; P = 0.32.FVH and flow patterns on 4D MR angiograms are markers of perfusion deficits and tissue at risk. As both methods did not show a correlation between each other, they seem to provide complimentary instead of redundant information. Previously shown evidence for the meaning of these specific MR signs in internal carotid and middle cerebral artery stroke seems to be transferrable to ischemic stroke in the ACA territory.

  2. Increased oxidative stress and severe arterial remodeling induced by permanent high-flow challenge in experimental pulmonary hypertension

    Fadel Elie

    2011-09-01

    Full Text Available Abstract Background Involvement of inflammation in pulmonary hypertension (PH has previously been demonstrated and recently, immune-modulating dendritic cells (DCs infiltrating arterial lesions in patients suffering from idiopathic pulmonary arterial hypertension (IPAH and in experimental monocrotaline-induced PH have been reported. Occurrence of perivascular inflammatory cells could be linked to local increase of oxidative stress (OS, as it has been shown for systemic atherosclerosis. The impact of OS on vascular remodeling in PH is still to be determined. We hypothesized, that augmented blood-flow could increase OS and might thereby contribute to DC/inflammatory cell-recruitment and smooth-muscle-cell-proliferation. Methods We applied a monocrotaline-induced PH-model and combined it with permanent flow-challenge. Thirty Sprague-Dawley rats were assigned to following groups: control, monocrotaline-exposure (MCT, monocrotaline-exposure/pneumonectomy (MCT/PE. Results Hemodynamic exploration demonstrated most severe effects in MCT/PE, corresponding in histology to exuberant medial and adventitial remodeling of pulmonary muscular arteries, and intimal remodeling of smaller arterioles; lung-tissue PCR evidenced increased expression of DCs-specific fascin, CD68, proinflammatory cytokines (IL-6, RANTES, fractalkine in MCT/PE and to a lesser extent in MCT. Major OS enzyme NOX-4 was maximal in MCT/PE. Antioxidative stress enzymes Mn-SOD and glutathion-peroxidase-1 were significantly elevated, while HO-1 showed maximal expression in MCT with significant decrease in MCT/PE. Catalase was decreased in MCT and MCT/PE. Expression of NOX-4, but also of MN-SOD in MCT/PE was mainly attributed to a highly increased number of interstitial and perivascular CXCR4/SDF1 pathway-recruited mast-cells. Stress markers malonedialdehyde and nitrotyrosine were produced in endothelial cells, medial smooth muscle and perivascular leucocytes of hypertensive vasculature

  3. Ocular fishhook injuries.

    Ang, C S

    2001-06-01

    Ocular fishhook injuries are rare, yet potentially vision threatening as complications such as corneal scarring, retinal detachment and endophthalmitis may result. The surgical management of these cases is challenging due to the construction of barbed fishhooks.

  4. THERAPY FOR OCULAR TOXOPLASMOSIS

    ROTHOVA, A; MEENKEN, C; BRINKMAN, CJ; BAARSMA, GS; BOENTAN, TN; DEJONG, PTVM; KLAASSENBROEKEMA, N; SCHWEITZER, CMC; TIMMERMAN, Z; DEVRIES, J; ZAAL, MJW; KIJLSTRA, A

    1993-01-01

    We conducted a prospective multicenter study of the efficacy of current therapeutic strategies for ocular toxoplasmosis in 149 patients. Treatment consisted of the following three triple-drug combinations: group 1, pyrimethamine, sulfadiazine, and corticosteroids; group 2, clindamycin, sulfadiazine,

  5. Mediators of ocular angiogenesis

    2016-08-26

    Aug 26, 2016 ... Keywords. ocular angiogenesis; corneal neovascularization; retinal neovascularization; diabetic retinopathy; age-related macular degeneration; retinopathy of prematurity; VEGF; PEDF; Flt-1; Flk-1; endostatin; angiopoietin; erythropoietin; Tie2; inflammation; complement; gene therapy; TLR-3; Robo4.

  6. Therapy for ocular toxoplasmosis

    Rothova, A.; Meenken, C.; Buitenhuis, H. J.; Brinkman, C. J.; Baarsma, G. S.; Boen-Tan, T. N.; de Jong, P. T.; Klaassen-Broekema, N.; Schweitzer, C. M.; Timmerman, Z.

    1993-01-01

    We conducted a prospective multicenter study of the efficacy of current therapeutic strategies for ocular toxoplasmosis in 149 patients. Treatment consisted of the following three triple-drug combinations: group 1, pyrimethamine, sulfadiazine, and corticosteroids; group 2, clindamycin, sulfadiazine,

  7. Challenging ocular image recognition

    Pauca, V. Paúl; Forkin, Michael; Xu, Xiao; Plemmons, Robert; Ross, Arun A.

    2011-06-01

    Ocular recognition is a new area of biometric investigation targeted at overcoming the limitations of iris recognition performance in the presence of non-ideal data. There are several advantages for increasing the area beyond the iris, yet there are also key issues that must be addressed such as size of the ocular region, factors affecting performance, and appropriate corpora to study these factors in isolation. In this paper, we explore and identify some of these issues with the goal of better defining parameters for ocular recognition. An empirical study is performed where iris recognition methods are contrasted with texture and point operators on existing iris and face datasets. The experimental results show a dramatic recognition performance gain when additional features are considered in the presence of poor quality iris data, offering strong evidence for extending interest beyond the iris. The experiments also highlight the need for the direct collection of additional ocular imagery.

  8. The optimization of iloprost inhalation under moderate flow of oxygen therapy in severe pulmonary arterial hypertension.

    Nakayama, Kazuhiko; Emoto, Noriaki; Tamada, Naoki; Okano, Mitsumasa; Shinkura, Yuto; Yanaka, Kenichi; Onishi, Hiroyuki; Hiraishi, Mana; Yamada, Shinichiro; Tanaka, Hidekazu; Shinke, Toshiro; Hirata, Ken-Ichi

    2018-01-01

    Inhaled iloprost efficiently improves pulmonary hemodynamics, exercise capacity, and quality of life in patients with pulmonary arterial hypertension (PAH). However, the process of inhalation is laborious for patients suffering from resting dyspnea. We describe a 75-year-old man with idiopathic PAH and a low gas transfer. Investigations excluded significant parenchymal lung disease and airflow obstruction (presuming FEV1/FVC ration > 70%). The patient struggled to complete iloprost inhalation due to severe dyspnea and hypoxemia. As such, we optimized the methods of oxygen supply from the nasal cannula to the trans-inhalator during the inhalation. We successfully shortened the inhalation duration that effectively reduced the laborious efforts required of patients. We also recorded pulmonary hemodynamics during inhalation of nebulized iloprost. This revealed significant hemodynamic improvement immediately following inhalation but hemodynamics returned to baseline within 2 hours. We hope that this optimization will enable patients with severe PAH to undergo iloprost inhalation.

  9. Analysis of Blood Flow Through a Viscoelastic Artery using the Cosserat Continuum with the Large-Amplitude Oscillatory Shear Deformation Model

    Sedaghatizadeh, N.; Atefi, G.; Fardad, A. A.

    2011-01-01

    In this investigation, semiempirical and numerical studies of blood flow in a viscoelastic artery were performed using the Cosserat continuum model. The large-amplitude oscillatory shear deformation model was used to quantify the nonlinear viscoelastic response of blood flow. The finite differenc...... method was used to solve the governing equations, and the particle swarm optimization algorithm was utilized to identify the non-Newtonian coefficients (kυ and γυ). The numerical results agreed well with previous experimental results....

  10. C-14-activity incorporation into the protein of fetal organs of guinea pigs with different maternal placental blood flow and fetal arterial O2-saturation

    Duenzl, B.

    1981-01-01

    In anaesthesised gravid guinea-pigs the dilate, end section of a placental radial artery was connected to the A.carotis via a flow meter and a throttle in order to measure and widely alter the maternal placental blood flow. Blood samples are taken from the fetal A.carotis, the fetal arterial O 2 -saturation and the Hb-content were determined. By altering the maternal placental blood circulation the fetal arterial O 2 -concentration can stabilised at various levels. In order to study the protein synthesis, under these conditions one infused 185 kBq C-14-leucine over a period of 3 hours into the jugular vein of the fetus. During infusion the radioactive concentrations in whole plasma and plasma water were measured. After the infusion the radioactive concentrations in the tissue fluid, the intracellular fluid and the acid-insoluble tissue fraction (protein) of the heart, kidenys, liver, the muscles of the upper end lower part of the body, the brain and the placenta were measured. The following deductions were drawn from the findings: The maternal placental blood flow vitally influences the activity incorporation per activity concentration in the plasma water. These findings agree with the hypotheses that the maternal blood circulation has an essential influence on the fetal proteins synthesis and that this influence can be attributed to the connection between placenta connection blood flow and oxygen saturation of fetal arterial blood. (orig.) [de

  11. Fusiform dilatation of the internal carotid artery following childhood craniopharyngioma resection treated by endovascular flow diversion-A case report and literature review.

    Reynolds, Matthew R; Heiferman, Daniel M; Boucher, Andrew B; Serrone, Joseph C; Barrow, Daniel L; Dion, Jacques E

    2018-05-24

    Fusiform dilatation of the internal carotid artery (FDICA) is a well-described radiographic finding following resection of childhood craniopharyngioma (CP). A 39-year-old woman with right-sided FDICA was successfully treated for lesion enlargement with endovascular flow diversion, which has not been described in the literature. Published by Elsevier Ltd.

  12. Quantitative agreement between [(15)O]H2O PET and model free QUASAR MRI-derived cerebral blood flow and arterial blood volume

    Heijtel, D. F. R.; Petersen, E. T.; Mutsaerts, H. J. M. M.; Bakker, E.; Schober, P.; Stevens, M. F.; van Berckel, B. N. M.; Majoie, C. B. L. M.; Booij, J.; van Osch, M. J. P.; van Bavel, E. T.; Boellaard, R.; Lammertsma, A. A.; Nederveen, A. J.

    2016-01-01

    The purpose of this study was to assess whether there was an agreement between quantitative cerebral blood flow (CBF) and arterial cerebral blood volume (CBVA) measurements by [(15)O]H2O positron emission tomography (PET) and model-free QUASAR MRI. Twelve healthy subjects were scanned within a week

  13. Distinct alterations in sublingual microcirculatory blood flow and hemoglobin oxygenation in on-pump and off-pump coronary artery bypass graft surgery

    Atasever, Bektaş; Boer, Christa; Goedhart, Peter; Biervliet, Jules; Seyffert, Jan; Speekenbrink, Ron; Schwarte, Lothar; de Mol, Bas; Ince, Can

    2011-01-01

    The authors hypothesized that cardiopulmonary bypass (CPB) (on-pump) is associated with more severe changes in the microcirculatory blood flow and tissue oxygenation as compared with off-pump coronary artery bypass surgery. An observational study. A university hospital and teaching hospital.

  14. Coupling between arterial and venous cerebral blood flow during postural change

    Ogoh, Shigehiko; Washio, Takuro; Sasaki, Hiroyuki

    2016-01-01

    In supine humans the main drainage from the brain is through the internal jugular vein (IJV) but the vertebral veins (VV) become important during orthostatic stress because the IJV is partially collapsed. To identify the effect of this shift in venous drainage from the brain on the cerebral...... blood flow (r=0.649, P=0.004) and the two flows were coupled during manipulation of the end-tidal CO2 tension (supine, r=0.551, P=0.004; seated, r=0.612, P

  15. Gradient changes in porcine renal arterial vascular anatomy and blood flow after cryoablation

    Lagerveld, B.W.; Horssen, van P.; Laguna, M.P.; Wijngaard, van den J.P.H.M.; Siebes, M.; Wijkstra, H.; Rosette, de la J.J.M.C.H.; Spaan, J.A.E.

    2011-01-01

    Purpose We quantified temporal changes in vascular structure and blood flow after cryosurgery of the porcine kidney in vivo. Materials and Methods We studied 5 groups of 4 kidneys each with a survival time of 20 minutes, 4 hours, 2 days, and 1 and 2 weeks after cryoablation, respectively. Before

  16. Flow studies in canine artery bifurcations using a numerical simulation method.

    Xu, X Y; Collins, M W; Jones, C J

    1992-11-01

    Three-dimensional flows through canine femoral bifurcation models were predicted under physiological flow conditions by solving numerically the time-dependent three-dimensional Navier-stokes equations. In the calculations, two models were assumed for the blood, those of (a) a Newtonian fluid, and (b) a non-Newtonian fluid obeying the power law. The blood vessel wall was assumed to be rigid this being the only approximation to the prediction model. The numerical procedure utilized a finite volume approach on a finite element mesh to discretize the equations, and the code used (ASTEC) incorporated the SIMPLE velocity-pressure algorithm in performing the calculations. The predicted velocity profiles were in good qualitative agreement with the in vivo measurements recently obtained by Jones et al. The non-Newtonian effects on the bifurcation flow field were also investigated, and no great differences in velocity profiles were observed. This indicated that the non-Newtonian characteristics of the blood might not be an important factor in determining the general flow patterns for these bifurcations, but could have local significance. Current work involves modeling wall distensibility in an empirically valid manner. Predictions accommodating these will permit a true quantitative comparison with experiment.

  17. Numerical analysis of blood flow in realistic arteries subjected to strong non-uniform magnetic fields

    Kenjeres, S.

    2008-01-01

    The paper reports on a comprehensive mathematical model for simulations of blood flow under the presence of strong non-uniform magnetic fields. The model consists of a set of Navier–Stokes equations accounting for the Lorentz and magnetisation forces, and a simplified set of Maxwell’s equations

  18. Gradient changes in porcine renal arterial vascular anatomy and blood flow after cryoablation

    Lagerveld, Brunolf W.; van Horssen, Pepijn; Laguna, M. Pilar; van den Wijngaard, Jeroen P. H. M.; Siebes, Maria; Wijkstra, Hessel; de La Rosette, Jean J. M. C. H.; Spaan, Jos A. E.

    2011-01-01

    We quantified temporal changes in vascular structure and blood flow after cryosurgery of the porcine kidney in vivo. We studied 5 groups of 4 kidneys each with a survival time of 20 minutes, 4 hours, 2 days, and 1 and 2 weeks after cryoablation, respectively. Before harvesting the kidneys,

  19. Intraoperative vascular anatomy, arterial blood flow velocity, and microcirculation in unilateral and bilateral cleft lip repair

    Mueller, A.A.; Schumann, D.; Reddy, R.R.; Schwenzer-Zimmerer, K.; Mueller-Gerbl, M.; Zeilhofer, H.F.; Sailer, H.F.; Reddy, S.G.

    2012-01-01

    BACKGROUND: Cleft lip repair aims to normalize the disturbed anatomy and function. The authors determined whether normalization of blood circulation is achieved. METHODS: The authors measured the microcirculatory flow, oxygen saturation, and hemoglobin level in the lip and nose of controls (n = 22)

  20. 4D cardiovascular magnetic resonance velocity mapping of alterations of right heart flow patterns and main pulmonary artery hemodynamics in tetralogy of Fallot

    2012-01-01

    Background To assess changes in right heart flow and pulmonary artery hemodynamics in patients with repaired Tetralogy of Fallot (rTOF) we used whole heart, four dimensional (4D) velocity mapping (VM) cardiovascular magnetic resonance (CMR). Methods CMR studies were performed in 11 subjects with rTOF (5M/6F; 20.1 ± 12.4 years) and 10 normal volunteers (6M/4F; 34.2 ± 13.4 years) on clinical 1.5T and 3.0T MR scanners. 4D VM-CMR was performed using PC VIPR (Phase Contrast Vastly undersampled Isotropic Projection Reconstruction). Interactive streamline and particle trace visualizations of the superior and inferior vena cava (IVC and SVC, respectively), right atrium (RA), right ventricle (RV), and pulmonary artery (PA) were generated and reviewed by three experienced readers. Main PA net flow, retrograde flow, peak flow, time-to-peak flow, peak acceleration, resistance index and mean wall shear stress were quantified. Differences in flow patterns between the two groups were tested using Fisher's exact test. Differences in quantitative parameters were analyzed with the Kruskal-Wallis rank sum test. Results 4D VM-CMR was successfully performed in all volunteers and subjects with TOF. Right heart flow patterns in rTOF subjects were characterized by (a) greater SVC/IVC flow during diastole than systole, (b) increased vortical flow patterns in the RA and in the RV during diastole, and (c) increased helical or vortical flow features in the PA's. Differences in main PA retrograde flow, resistance index, peak flow, time-to-peak flow, peak acceleration and mean wall shear stress were statistically significant. Conclusions Whole heart 4D VM-CMR with PC VIPR enables detection of both normal and abnormal right heart flow patterns, which may allow for comprehensive studies to evaluate interdependencies of post-surgically altered geometries and hemodynamics. PMID:22313680

  1. Noncontrast magnetic resonance angiography of the hand: improved arterial conspicuity by multidirectional flow-sensitive dephasing magnetization preparation in 3D balanced steady-state free precession imaging.

    Fan, Zhaoyang; Hodnett, Philip A; Davarpanah, Amir H; Scanlon, Timothy G; Sheehan, John J; Varga, John; Carr, James C; Li, Debiao

    2011-08-01

    : To develop a flow-sensitive dephasing (FSD) preparative scheme to facilitate multidirectional flow-signal suppression in 3-dimensional balanced steady-state free precession imaging and to validate the feasibility of the refined sequence for noncontrast magnetic resonance angiography (NC-MRA) of the hand. : A new FSD preparative scheme was developed that combines 2 conventional FSD modules. Studies using a flow phantom (gadolinium-doped water 15 cm/s) and the hands of 11 healthy volunteers (6 males and 5 females) were performed to compare the proposed FSD scheme with its conventional counterpart with respect to the signal suppression of multidirectional flow. In 9 of the 11 healthy subjects and 2 patients with suspected vasculitis and documented Raynaud phenomenon, respectively, 3-dimensional balanced steady-state free precession imaging coupled with the new FSD scheme was compared with spatial-resolution-matched (0.94 × 0.94 × 0.94 mm) contrast-enhanced magnetic resonance angiography (0.15 mmol/kg gadopentetate dimeglumine) in terms of overall image quality, venous contamination, motion degradation, and arterial conspicuity. : The proposed FSD scheme was able to suppress 2-dimensional flow signal in the flow phantom and hands and yielded significantly higher arterial conspicuity scores than the conventional scheme did on NC-MRA at the regions of common digitals and proper digitals. Compared with contrast-enhanced magnetic resonance angiography, the refined NC-MRA technique yielded comparable overall image quality and motion degradation, significantly less venous contamination, and significantly higher arterial conspicuity score at digital arteries. : The FSD-based NC-MRA technique is improved in the depiction of multidirectional flow by applying a 2-module FSD preparation, which enhances its potential to serve as an alternative magnetic resonance angiography technique for the assessment of hand vascular abnormalities.

  2. Effects of Insulin Resistance on Myocardial Blood Flow and Arterial Peripheral Circulation in Patients with Polycystic Ovary Syndrome.

    Aldrighi, José M; Tsutsui, Jeane M; Kowastch, Ingrid; Ribeiro, Alessandra L; Scapinelli, Alessandro; Tamanaha, Sonia; Oliveira, Ricardo M; Mathias, Wilson

    2015-08-01

    Polycystic ovary syndrome (PCOS) is associated with increased risk for cardiovascular disease. We sought to evaluate the effects of insulin resistance (IR) on myocardial microcirculation and peripheral artery function in patients with PCOS. We studied 55 women (28 with PCOS without IR, 18 with PCOS and IR and 11 normal controls) who underwent laboratorial analysis, high-resolution vascular ultrasound and real time myocardial contrast echocardiography (RTMCE). Intima-media thickness (IMT) and brachial artery flow-mediated dilation (FMD) were evaluated by vascular ultrasound. The replenishment velocity (β), plateau of acoustic intensity (A) and myocardial blood flow reserve (MBFR) were determined by quantitative dipyridamole stress RTMCE. β reserve in group PCOS + IR was lower than control (2.34 ± 0.55 vs. 3.60 ± 0.6; P PCOS without IR (2.34 ± 0.55 vs. 3.17 ± 0.65; P PCOS without IR did not differ from those of control (4.59 ± 1.59 vs. 5.30 ± 1.64; P = 0.22) or from patients with PCOS + IR (4.59 ± 1.59 vs. 3.70 ± 1.47; P = 0.07). When comparing with control group, patients with PCOS + IR had lower MBFR (5.30 ± 1.64 vs. 3.70 ± 1.47; P = 0.01). No significant differences were found between control, PCOS without IR and PCOS + IR for FMD (0.18 ± 0.05, 0.15 ± 0.04 and 0.13 ± 0.07; P =NS) or IMT (0.48 ± 0.05, 0.47 ± 0.05 and 0.49 ± 0.07; P = NS). Women with PCOS and IR had depressed β and MBFR as demonstrated by quantitative RTMCE, but no alteration in endothelial dysfunction or IMT. PCOS without IR showed isolated depression in β reserve, probably an earlier marker of myocardial flow abnormality. © 2014, Wiley Periodicals, Inc.

  3. Use of a Novel Abdominal Aortic and Junctional Tourniquet to Reduce or Eliminate Flow in the Brachial and Popliteal Arteries in Human Subjects.

    Lyon, Matthew; Johnson, Daniel; Gordon, Richard

    2015-01-01

    Penetrating injuries of the proximal large arteries are a common cause of death on the battlefield due to rapid exsanguination. Applying an effective tourniquet to stop bleeding at the axillary and proximal femoral arteries (junctional sites) is difficult. Prior studies have shown that the Abdominal Aortic and Junctional Tourniquet (AAJT) effectively reduced blood flow in the common femoral artery with application of the device around the lower abdomen. Our objective was to determine the effectiveness of the AAJT to stop blood flow in the proximal femoral artery (PFA), and the axillary artery (AA). This was a prospective observational trial using human volunteers. The AAJT consists of a wedge-shaped bladder and integrated strap. The bladder has an integrated manometer, which is used to measure the pressure in the bladder. For the AA, the AAJT was placed over the axillary junction at the anterior axillary line with the strap placed across the contralateral shoulder. For the PFA, the AAJT bladder was placed over the right groin with the strap positioned across both femoral trochanters. Spectral Doppler measurements were taken of the PFA and AA at baseline and as the bladder was inflated. Collected data included pressure of the AAJT.

  4. Lattice Boltzmann Model of 3D Multiphase Flow in Artery Bifurcation Aneurysm Problem

    Aizat Abas

    2016-01-01

    Full Text Available This paper simulates and predicts the laminar flow inside the 3D aneurysm geometry, since the hemodynamic situation in the blood vessels is difficult to determine and visualize using standard imaging techniques, for example, magnetic resonance imaging (MRI. Three different types of Lattice Boltzmann (LB models are computed, namely, single relaxation time (SRT, multiple relaxation time (MRT, and regularized BGK models. The results obtained using these different versions of the LB-based code will then be validated with ANSYS FLUENT, a commercially available finite volume- (FV- based CFD solver. The simulated flow profiles that include velocity, pressure, and wall shear stress (WSS are then compared between the two solvers. The predicted outcomes show that all the LB models are comparable and in good agreement with the FVM solver for complex blood flow simulation. The findings also show minor differences in their WSS profiles. The performance of the parallel implementation for each solver is also included and discussed in this paper. In terms of parallelization, it was shown that LBM-based code performed better in terms of the computation time required.

  5. Comparison of fractional flow reserve measurements using intracoronary adenosine versus intracoronary sodium nitroprusside infusions in moderately stenotic coronary artery lesions

    Safi, Morteza; Namazi, Mohammad Hasan; Fooladi, Esfandiar; Vakili, Hossein; Parsa, Saeed Alipour; Khaheshi, Isa [Cardiovascular Research Center, Modarres hospital, Shahid Beheshti University of Medical Sciences, Tehran (Iran, Islamic Republic of); Abbasi, Mohammad Amin [Department of Internal Medicine, Shahid Beheshti University of Medical Sciences, Tehran (Iran, Islamic Republic of); Movahed, Mohammad Reza, E-mail: rmova@aol.com [CareMore, Arizona, Tucson, AZ (United States); University of Arizona, Sarver Heart Center, Tucson, AZ (United States)

    2016-10-15

    Introduction: The aim of this study was to investigate the efficacy and safety of intracoronary (IC) sodium nitroprusside infusion in comparison to IC adenosine for fractional flow reserve (FFR) measurement in moderately diseased coronary artery lesions for functional assessment. Methods: During a nine month period, a consecutive of 98 patients with suspected or known coronary artery disease with moderate stenosis found during angiography (40% to 70% stenosis), were enrolled in this study. Hyperemia was induced by bolus doses of IC adenosine followed by sodium nitroprusside for FFR measurement. Results: Both IC adenosine and IC sodium nitroprusside induced similar and significant reduction in FFR. There was no statistically difference in FFR values between adenosine vs sodium nitroprusside infusions (mean FFR 84.3 ± 6.3 vs 85.7 ± 6.2, p = 0.1) respectively. Furthermore, comparing different FFR cut-off points between the groups (FFR < 0.75, 0.75–0.8 and > 0.8) showed no significant differences (p value = 0.7). Conclusion: An IC bolus of sodium nitroprusside (0.6 μg/kg) infusion induces a similar degree of hyperemia to IC bolus of 100–300 μg of adenosine. Therefore, IC sodium nitroprusside could be considered as an alternative drug to adenosine for FFR measurement with lower side effect profile. - Highlights: • Intracoronary (IC) sodium nitroprusside was compared with IC adenosine for FFR test. • IC adenosine and IC sodium nitroprusside induced similar reduction in FFR. • Different FFR cut-off points between the groups showed no significant differences. • IC sodium nitroprusside could be considered as an alternative to adenosine for FFR.

  6. Structural alterations of the coronary arterial wall are associated with myocardial flow heterogeneity in type 2 diabetes mellitus

    Schindler, Thomas H.; Facta, Alvaro D.; Prior, John O.; Cadenas, Jerson; Zhang, Xiao-Li; Sayre, James; Goldin, Jonathan; Schelbert, Heinrich R.

    2009-01-01

    To determine the relationship between carotid intima-media thickness (IMT), coronary artery calcification (CAC), and myocardial blood flow (MBF) at rest and during vasomotor stress in type 2 diabetes mellitus (DM). In 68 individuals, carotid IMT was measured using high-resolution vascular ultrasound, while the presence of CAC was determined with electron beam tomography (EBT). Global and regional MBF was determined in milliliters per gram per minute with 13 N-ammonia and positron emission tomography (PET) at rest, during cold pressor testing (CPT), and during adenosine (ADO) stimulation. There was neither a relationship between carotid IMT and CAC (r = 0.10, p = 0.32) nor between carotid IMT and coronary circulatory function in response to CPT and during ADO (r = -0.18, p = 0.25 and r = 0.10, p = 0.54, respectively). In 33 individuals, EBT detected CAC with a mean Agatston-derived calcium score of 44 ± 18. There was a significant difference in regional MBFs between territories with and without CAC at rest and during ADO-stimulated hyperemia (0.69 ± 0.24 vs. 0.74 ± 0.23 and 1.82 ± 0.50 vs. 1.95 ± 0.51 ml/g/min; p ≤ 0.05, respectively) and also during CPT in DM but less pronounced (0.81 ± 0.24 vs. 0.83 ± 0.23 ml/g/min; p = ns). The increase in CAC was paralleled with a progressive regional decrease in resting as well as in CPT- and ADO-related MBFs (r = -0.36, p ≤ 0.014; r = -0.46, p ≤ 0.007; and r = -0.33, p ≤ 0.041, respectively). The absence of any correlation between carotid IMT and coronary circulatory function in type 2 DM suggests different features and stages of early atherosclerosis in the peripheral and coronary circulation. PET-measured MBF heterogeneity at rest and during vasomotor stress may reflect downstream fluid dynamic effects of coronary artery disease (CAD)-related early structural alterations of the arterial wall. (orig.)

  7. Successful management with glue injection of arterial rupture seen during embolization of an arteriovenous malformation using a flow-directed catheter: a case report

    Hong, Jong Won; Baik, Seung Kug; Shin, Mi Jung; Choi, Han Yong; Kim, Bong Gi [Wallace Memorial Baptist Hospital, Pusan (Korea, Republic of)

    2000-12-01

    We present a case in which an arterial rupture occurring during embolization of an arteriovenous malformation of the left occipital lobe with a flow-directed micro-catheter, was successfully sealed with a small amount of glue. We navigated a 1.8-Fr Magic catheter through the posterior cerebral artery, and during superselective test injection, extravasation was observed at the parieto-occipital branch. The catheter was not removed and the perforation site was successfully sealed with a small amount of glue injected through the same catheter. Prompt recognition and closure of the perforation site is essential for good prognosis. (author)

  8. Arterial embolism

    ... when a clot in a vein enters the right side of the heart and passes through a hole into the left side. The clot can then move to an artery and block blood flow to the brain (stroke) or other organs. If a clot involves ...

  9. Numerical study of magnetohydrodynamic pulsatile flow of Sutterby fluid through an inclined overlapping arterial stenosis in the presence of periodic body acceleration

    Abbas, Z.; Shabbir, M. S.; Ali, N.

    2018-06-01

    In the present theoretical investigation, we have numerically simulated the problem of blood flow through an overlapping stenosed arterial blood vessel under the action of externally applied body acceleration and the periodic pressure gradient. The rheology of blood is characterized by the Sutterby fluid model. The blood is considered as an electrically conducting fluid. A steady uniform magnetic field is applied in the radial direction of the blood vessel. The governing nonlinear partial differential equations of the present flow together with prescribed boundary conditions are solved by employing explicit finite difference scheme. Results concerning the temporal distribution of velocity, flow rate, shear stress and resistance to the flow are displayed through graphs. The effects of various emerging parameters on the flow variables are analyzed and discussed in detail. The analysis reveals that the applied magnetic field and periodic body acceleration have considerable effects on the flow field.

  10. Penile angiography and superselective embolization therapy in arterial priapism; Penisangiographie und superselektive Embolisationstherapie bei high-flow Priapismus

    Dinkel, H.P.; Triller, J. [Inst. fuer Diagnostische Radiologie, Inselspital, Univ. Bern (Switzerland); Hochreiter, W. [Urologische Klinik, Inselspital, Univ. Bern (Switzerland)

    2003-08-01

    Purpose: To report feasibility, benefit and complications of penile angiography and superselective penile embolization in arterial priapism. Materials and Methods: Four consecutive patients (aged 28, 29, 40 and 49 years), who underwent penile angiography for arterial priapism (high-flow priapism) within a four-year period, were identified by a keyword search of our radiology information system. One patient had sustained a direct penile trauma (severe blow to the erected penis) and three patients suffered from recurrent spontaneous priapism. All patients had previously undergone corporeal aspiration and noradrenaline injection to achieve detumescence. Two patients had one or several unsuccessful spongiocavernous shunt procedures. Results: In three of the four patients, superselective pudendal and penile angiography demonstrated pathologic arteriocavernous shunting. In two of the three patients, superselective embolization using a coaxial micro-catheter was attempted. In one of the two patients, the cavernous artery became spastic before embolization material was actually injected, inducing immediate and lasting detumescence. In the other patient, unilateral Gelfoam embolization led to immediate detumescence but the priapism recurred 12 hours after the procedure. A subsequent contralateral Gelfoam embolization was successful. Erectile function was preserved in all cases. No procedure-related complications occurred. Conclusion: Our experience supports the prevailing opinion found in the current literature that superselective coaxial embolization constitutes the treatment of choice in patients with high-flow priapism. Prognosis is good with high probability of preserving the erectile function. (orig.) [German] Ziel: Untersuchung der Interventionsmoeglichkeiten bei arteriellem (high-flow) Priapismus durch endovaskulaere superselektive Embolisation der Penisarterien. Methode: Alle innerhalb eines Vierjahreszeitraums (1/99-5/2002) wegen Priapismus zur Angiographie

  11. Decreased arterial PO2, not O2 content, increases blood flow through intrapulmonary arteriovenous anastomoses at rest.

    Duke, Joseph W; Davis, James T; Ryan, Benjamin J; Elliott, Jonathan E; Beasley, Kara M; Hawn, Jerold A; Byrnes, William C; Lovering, Andrew T

    2016-09-01

    The mechanism(s) that regulate hypoxia-induced blood flow through intrapulmonary arteriovenous anastomoses (QIPAVA ) are currently unknown. Our previous work has demonstrated that the mechanism of hypoxia-induced QIPAVA is not simply increased cardiac output, pulmonary artery systolic pressure or sympathetic nervous system activity and, instead, it may be a result of hypoxaemia directly. To determine whether it is reduced arterial PO2 (PaO2) or O2 content (CaO2) that causes hypoxia-induced QIPAVA , individuals were instructed to breathe room air and three levels of hypoxic gas at rest before (control) and after CaO2 was reduced by 10% by lowering the haemoglobin concentration (isovolaemic haemodilution; Low [Hb]). QIPAVA , assessed by transthoracic saline contrast echocardiography, significantly increased as PaO2 decreased and, despite reduced CaO2 (via isovolaemic haemodilution), was similar at iso-PaO2. These data suggest that, with alveolar hypoxia, low PaO2 causes the hypoxia-induced increase in QIPAVA , although where and how this is detected remains unknown. Alveolar hypoxia causes increased blood flow through intrapulmonary arteriovenous anastomoses (QIPAVA ) in healthy humans at rest. However, it is unknown whether the stimulus regulating hypoxia-induced QIPAVA is decreased arterial PO2 (PaO2) or O2 content (CaO2). CaO2 is known to regulate blood flow in the systemic circulation and it is suggested that IPAVA may be regulated similar to the systemic vasculature. Thus, we hypothesized that reduced CaO2 would be the stimulus for hypoxia-induced QIPAVA . Blood volume (BV) was measured using the optimized carbon monoxide rebreathing method in 10 individuals. Less than 5 days later, subjects breathed room air, as well as 18%, 14% and 12.5% O2 , for 30 min each, in a randomized order, before (CON) and after isovolaemic haemodilution (10% of BV withdrawn and replaced with an equal volume of 5% human serum albumin-saline mixture) to reduce [Hb] (Low [Hb]). PaO2

  12. Arterial stiffness, pressure and flow pulsatility and brain structure and function: the Age, Gene/Environment Susceptibility--Reykjavik study.

    Mitchell, Gary F; van Buchem, Mark A; Sigurdsson, Sigurdur; Gotal, John D; Jonsdottir, Maria K; Kjartansson, Ólafur; Garcia, Melissa; Aspelund, Thor; Harris, Tamara B; Gudnason, Vilmundur; Launer, Lenore J

    2011-11-01

    Aortic stiffness increases with age and vascular risk factor exposure and is associated with increased risk for structural and functional abnormalities in the brain. High ambient flow and low impedance are thought to sensitize the cerebral microcirculation to harmful effects of excessive pressure and flow pulsatility. However, haemodynamic mechanisms contributing to structural brain lesions and cognitive impairment in the presence of high aortic stiffness remain unclear. We hypothesized that disproportionate stiffening of the proximal aorta as compared with the carotid arteries reduces wave reflection at this important interface and thereby facilitates transmission of excessive pulsatile energy into the cerebral microcirculation, leading to microvascular damage and impaired function. To assess this hypothesis, we evaluated carotid pressure and flow, carotid-femoral pulse wave velocity, brain magnetic resonance images and cognitive scores in participants in the community-based Age, Gene/Environment Susceptibility--Reykjavik study who had no history of stroke, transient ischaemic attack or dementia (n = 668, 378 females, 69-93 years of age). Aortic characteristic impedance was assessed in a random subset (n = 422) and the reflection coefficient at the aorta-carotid interface was computed. Carotid flow pulsatility index was negatively related to the aorta-carotid reflection coefficient (R = -0.66, Pwave velocity were each associated with increased risk for silent subcortical infarcts (hazard ratios of 1.62-1.71 per standard deviation, Pwave velocity was associated with higher white matter hyperintensity volume (0.108 ± 0.045 SD/SD, P = 0.018). Pulsatility index was associated with lower whole brain (-0.127 ± 0.037 SD/SD, Pwave velocity (-0.095 ± 0.043 SD/SD, P = 0.028) and carotid pulse pressure (-0.114 ± 0.045 SD/SD, P = 0.013) were associated with lower memory scores. Pulsatility index was associated with lower memory scores (-0.165 ± 0.039 SD/SD, Pwave

  13. Color Doppler Indices of Orbital Arterial Flow in End-Stage Renal Disease Patients; Are the Changes Related to Chronic Hemodialysis or Chronic Renal Failure?

    Rokni Yazdi, Hadi; Faraji, Safoura; Ahmadi, Farokhlegha; Shahmirzae, Reza

    2012-01-01

    Endothelial injury is a well-known complication in chronic kidney disease (CKD) and hemodialysis. One of the sites in which early vascular changes may be detected is the retina. Of course, these flow changes may not be detected in ophthalmologic exams, but it seems that color Doppler sonography of retinal arteries may be helpful in these cases. In previous studies on CKD patients who underwent chronic hemodialysis,hemodynamic changes were noted in retinal arteries, but no study has been performed to determine which of the two processes (CKD or chronic hemodialysis) can produce these changes. In this study, we tried to answer this question. Doppler ultrasonography of the orbital vasculature including the ophthalmic artery and the central retinal artery was carried out in 17 patients (34 eyes) with chronic renal failure (CRF) who underwent hemodialysis, 17 patients (34 eyes)with CRF without a history of hemodialysis and 17 normal patients (34 eyes). The peak systolic velocity (PSV), end diastolic velocity (EDV) and resistance index were measured excluding hypertensive, diabetic patients and patients with cardiovascular disease. The mean PSV and EDV were lower only in the ophthalmic artery of CRF patients irrespective of the history of hemodialysis (PSV was 35.2 in hemodialysis, 38.8 in CRF and 51.6 in normal patients, P value = 0.001 and EDV was 7.4, 9.4, 11.8, respectively, P value =0.001) with no significant difference in the resistance index of the ophthalmic artery and other parameters [EDV, PSV, Resistance Index (RI)] in the central retinal artery. The mean PSV and DSV in the ophthalmic artery were lower only in the ophthalmic artery of CRF patients regardless of the history of hemodialysis. No significant difference in the resistance index of the ophthalmic artery and other parameters (EDV, PSV) of the central retinal artery were noted between different groups. These findings suggest that microvascular disease and endothelial cell dysfunction of the orbital

  14. Assessment of coronary flow reserve by sestamibi imaging in patients with typical chest pain and normal coronary arteries

    Storto, Giovanni; Sorrentino, Anna R.; Pellegrino, Teresa; Liuzzi, Raffaele; Cuocolo, Alberto [University Federico II, Department of Biomorphological and Functional Sciences, Institute of Biostructures and Bioimages of the National Council of Research, Naples (Italy); Petretta, Mario [University Federico II, Department of Internal Medicine, Cardiovascular and Immunological Sciences, Naples (Italy)

    2007-08-15

    We assessed coronary flow reserve (CFR) by sestamibi imaging in patients with typical chest pain, positive exercise stress test and normal coronary vessels. Thirty-five patients with typical chest pain and normal angiogram and 12 control subjects with atypical chest pain underwent dipyridamole/rest {sup 99m}Tc-sestamibi imaging. Myocardial blood flow (MBF) was estimated by measuring first transit counts in the pulmonary artery and myocardial counts from SPECT images. Estimated CFR was expressed as the ratio of stress to rest MBF. Rest MBF and CFR were corrected for rate-pressure product (RPP) and expressed as normalised MBF (MBF{sub n}) and normalised CFR (CFR{sub n}). Coronary vascular resistances (CVR) were calculated as the ratio between mean arterial pressure and estimated MBF. At rest, estimated MBF and MBF{sub n} were lower in controls than in patients (0.98 {+-} 0.4 vs 1.30 {+-} 0.3 counts/pixel/s and 1.14 {+-} 0.5 vs 1.64 {+-} 0.6 counts/pixel/s, respectively, both p < 0.02). Stress MBF was not different between controls and patients (2.34 {+-} 0.8 vs 2.01 {+-} 0.7 counts/pixel/s, p=NS). Estimated CFR was 2.40 {+-} 0.3 in controls and 1.54 {+-} 0.3 in patients (p < 0.0001). After correction for the RPP, CFR{sub n} was still higher in controls than in patients (2.1 {+-} 0.5 vs 1.29 {+-} 0.5, p < 0.0001). At baseline, CVR values were lower (p < 0.01) in patients than in controls. Dipyridamole-induced changes in CVR were greater (p < 0.0001) in controls (-63%) than in patients (-35%). In the overall study population, a significant correlation between dipyridamole-induced changes in CVR and CFR was observed (r = -0.88, p < 0.0001). SPECT might represent a useful non-invasive method for assessing coronary vascular function in patients with angina and a normal coronary angiogram. (orig.)

  15. Relationships among Ocular Blood Flow Shown by Laser Speckle Flowgraphy, Retinal Arteriosclerotic Change, and Chorioretinal Circulation Time Obtained by Fluorescein Angiography

    Hironori Osamura

    2017-01-01

    Full Text Available Purpose. To determine the correlations among the mean blur rate (MBR in the optic nerve head (ONH shown by laser speckle flowgraphy (LSFG, retinal arteriosclerosis, and the circulation time obtained by fluorescein angiography (FA. Method. We evaluated 118 patients and assessed their time of choroidal flush, arm-to-retina time, and early and late phases of retinal circulation time (RT: sec obtained by FA. The severity of retinal arteriosclerosis was classified according to the Scheie classification. The MBR values throughout the ONH (MBR-A, in the tissue (MBR-T, and in the vessels (MBR-V were analyzed. Results. Patients with retinal vein occlusion (RVO showed prolonged early and late phases of RT compared to other ocular diseases. Single and multiple regression analyses showed that the MBR-V and Scheie classification were significantly associated with both the choroidal flush and arm-to-retina times. The incidences of RVO and MVR-V were significantly associated with the early phase of RT, and the incidences of RVO, MBR-V, Scheie classification, and gender were revealed to be factors independently contributing to the late phase of RT. Conclusion. MBR-V in the ONH and retinal arteriosclerosis are important contributing factors for the circulation time of each stage obtained by FA.

  16. Clinics of ocular tuberculosis.

    Gupta, Vishali; Shoughy, Samir S; Mahajan, Sarakshi; Khairallah, Moncef; Rosenbaum, James T; Curi, Andre; Tabbara, Khalid F

    2015-02-01

    Ocular tuberculosis is an extrapulmonary tuberculous condition and has variable manifestations. The purpose of this review is to describe the clinical manifestations of ocular tuberculosis affecting the anterior and posterior segments of the eye in both immunocompetent and immunocompromised patients. Review of literature using Pubmed database. Mycobacterium tuberculosis may lead to formation of conjunctival granuloma, nodular scleritis, and interstitial keratitis. Lacrimal gland and orbital caseating granulomas are rare but may occur. The intraocular structures are also a target of insult by M. tuberculosis and may cause anterior granulomatous uveitis, anterior and posterior synechiae, secondary glaucoma, and cataract. The bacillus may involve the ciliary body, resulting in the formation of a localized caseating granuloma. Posterior segment manifestations include vitritis, retinal vasculitis, optic neuritis, serpiginous-like choroiditis, choroidal tubercules, subretinal neovascularization, and, rarely, endophthalmitis. The recognition of clinical signs of ocular tuberculosis is of utmost importance as it can provide clinical pathway toward tailored investigations and decision making for initiating anti-tuberculosis therapy.

  17. Artefactos en ultrasonido ocular

    Mariana Mayorquín Ruiz

    2016-07-01

    Full Text Available El ultrasonido ocular es un estudio dependiente del operador. Un buen estudio ecográfico debe tener como base el conocimiento de la anatomía y fisiología normales y de los cambios producidos en diferentes enfermedades, así como los cambios tras una cirugía ocular o trauma. El conocimiento de los fenómenos físicos producidos por el ultrasonido es la base para entender y reconocer la presencia de artefactos en el ultrasonido ocular. Esta revisión tiene como objetivo hacer un recuento de los artefactos que pueden ocasionar confusión al interpretar una imagen ecográfica, así como explicar la base física en la que se basan, reduciendo de esta manera los errores de interpretación y diagnósticos.

  18. What Is an Ocular Migraine?

    ... When to seek help What is an ocular migraine? Is it a sign of something serious? Answers ... and retinal migraine, which could signal something serious. Migraine aura affecting your vision Ocular migraine sometimes describes ...

  19. Ocular complications of boxing

    Bianco, M; Vaiano, A; Colella, F; Coccimiglio, F; Moscetti, M; Palmieri, V; Focosi, F; Zeppilli, P; Vinger, P

    2005-01-01

    Objectives: To investigate the prevalence of ocular injuries in a large population of boxers over a period of 16 years, in particular, the most severe lesions that may be vision threatening. Methods: Clinical records of the medical archive of the Italian Boxing Federation were analysed. A total of 1032 boxers were examined from February 1982 to October 1998. A complete ophthalmological history was available for 956, who formed the study population (a total of 10 697 examinations). The following data were collected: age when started boxing; duration of competitive boxing career (from the date of the first bout); weight category; a thorough ocular history. The following investigations were carried out: measurement of visual acuity and visual fields, anterior segment inspection, applanation tonometry, gonioscopy, and examination of ocular fundus. Eighty age matched healthy subjects, who had never boxed, formed the control group. Results: Of the 956 boxers examined, 428 were amateur (44.8%) and 528 professional (55.2%). The median age at first examination was 23.1 (4.3) years (range 15–36). The prevalence of conjunctival, corneal, lenticular, vitreal, ocular papilla, and retinal alterations in the study population was 40.9% compared with 3.1% in the control group (p⩽0.0001). The prevalence of serious ocular findings (angle, lens, macula, and peripheral retina alterations) was 5.6% in boxers and 3.1% in controls (NS). Conclusions: Boxing does not result in a higher prevalence of severe ocular lesions than in the general population. However, the prevalence of milder lesions (in particular with regard to the conjunctiva and cornea) is noteworthy, justifying the need for adequate ophthalmological surveillance. PMID:15665199

  20. Flow and wall shear stress in end-to-side and side-to-side anastomosis of venous coronary artery bypass grafts

    Poulikakos Dimos

    2007-09-01

    Full Text Available Abstract Purpose Coronary artery bypass graft (CABG surgery represents the standard treatment of advanced coronary artery disease. Two major types of anastomosis exist to connect the graft to the coronary artery, i.e., by using an end-to-side or a side-to-side anastomosis. There is still controversy because of the differences in the patency rates of the two types of anastomosis. The purpose of this paper is to non-invasively quantify hemodynamic parameters, such as mass flow and wall shear stress (WSS, in end-to-side and side-to-side anastomoses of patients with CABG using computational fluid dynamics (CFD. Methods One patient with saphenous CABG and end-to-side anastomosis and one patient with saphenous CABG and side-to-side anastomosis underwent 16-detector row computed tomography (CT. Geometric models of coronary arteries and bypasses were reconstructed for CFD analysis. Blood flow was considered pulsatile, laminar, incompressible and Newtonian. Peri-anastomotic mass flow and WSS were quantified and flow patterns visualized. Results CFD analysis based on in-vivo CT coronary angiography data was feasible in both patients. For both types of CABG, flow patterns were characterized by a retrograde flow into the native coronary artery. WSS variations were found in both anastomoses types, with highest WSS values at the heel and lowest WSS values at the floor of the end-to-side anastomosis. In contrast, the highest WSS values of the side-to-side anastomosis configuration were found in stenotic vessel segments and not in the close vicinity of the anastomosis. Flow stagnation zones were found in end-to-side but not in side-to-side anastomosis, the latter also demonstrating a smoother stream division throughout the cardiac cycle. Conclusion CFD analysis of venous CABG based on in-vivo CT datasets in patients was feasible producing qualitative and quantitative information on mass flow and WSS. Differences were found between the two types of anastomosis

  1. Physiologic assessment of coronary artery disease: Focus on fractional flow reserve

    Hwang, Do Yeon; Koo, Bon Kwon [Dept. of Radiology, Internal Medicine and Cardiovascular Center, Seoul National University Hospital, Seoul (Korea, Republic of); Lee, Joo Myung [Dept. of Internal Medicine and Cardiovascular Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of)

    2016-06-15

    The presence of myocardial ischemia is the most important prognostic factor in patients with ischemic heart disease. Fractional flow reserve (FFR) is a gold standard invasive method used to detect the stenosis-specific myocardial ischemia. FFR-guided revascularization strategy is superior to angiography-guided strategy. The recently developed hyperemia-free index, instantaneous wave free ratio is being actively investigated. A non-invasive FFR derived from coronary CT angiography is now used in clinical practice. Due to rapid expansion of invasive and non-invasive physiologic assessment, comprehensive understanding of the role and potential pitfalls of each modality are required for its application. In this review, we focus on the basic and clinical aspects of physiologic assessment in ischemic heart disease.

  2. Physiologic assessment of coronary artery disease: Focus on fractional flow reserve

    Hwang, Do Yeon; Koo, Bon Kwon; Lee, Joo Myung

    2016-01-01

    The presence of myocardial ischemia is the most important prognostic factor in patients with ischemic heart disease. Fractional flow reserve (FFR) is a gold standard invasive method used to detect the stenosis-specific myocardial ischemia. FFR-guided revascularization strategy is superior to angiography-guided strategy. The recently developed hyperemia-free index, instantaneous wave free ratio is being actively investigated. A non-invasive FFR derived from coronary CT angiography is now used in clinical practice. Due to rapid expansion of invasive and non-invasive physiologic assessment, comprehensive understanding of the role and potential pitfalls of each modality are required for its application. In this review, we focus on the basic and clinical aspects of physiologic assessment in ischemic heart disease

  3. Profiling of oxidized phospholipids in lipoproteins from patients with coronary artery disease by hollow fiber flow field-flow fractionation and nanoflow liquid chromatography-tandem mass spectrometry.

    Lee, Ju Yong; Byeon, Seul Kee; Moon, Myeong Hee

    2015-01-20

    Oxidized phospholipids (Ox-PLs) are oxidatively modified PLs that are produced during the oxidation of lipoproteins; oxidation of low density lipoproteins especially is known to be associated with the development of coronary artery disease (CAD). In this study, different lipoprotein classes (high density, low density, and very low density lipoproteins) from pooled plasma of CAD patients and pooled plasma from healthy controls were size-sorted on a semipreparative scale by multiplexed hollow fiber flow field-flow fractionation (MxHF5), and Ox-PLs that were extracted from each lipoprotein fraction were quantified by nanoflow liquid chromatography-tandem mass spectrometry (nLC-ESI-MS/MS). The present study showed that oxidation of lipoproteins occurred throughout all classes of lipoproteins with more Ox-PLs identified from CAD patient lipoproteins: molecular structures of 283 unique PL species (including 123 Ox-PLs) from controls and 315 (including 169 Ox-PLs) from patients were identified by data-dependent collision-induced dissociation experiments. It was shown that oxidation of PLs occurred primarily with hydroxylation of PL; in particular, a saturated acyl chain such as 16:0, 18:0, or even 18:1 at the sn-1 location of the glycerol backbone along with sn-2 acyl chains with at least two double bonds were identified. The acyl chain combinations commonly found for hydroxylated Ox-PLs in the lipoproteins of CAD patients were 16:0/18:2, 16:0/20:4, 18:0/18:2, and 18:0/20:4.

  4. Coronary artery bypass grafting without cardiopulmonary bypass and without interruption of native coronary flow using a novel anastomosis site restraining device ("Octopus").

    Borst, C; Jansen, E W; Tulleken, C A; Gründeman, P F; Mansvelt Beck, H J; van Dongen, J W; Hodde, K C; Bredée, J J

    1996-05-01

    This study assessed the feasibility of coronary artery bypass grafting on the beating heart without interruption of native coronary blood flow using a novel anastomosis site restraining device. Recently, an end-to-side bypass technique was described that does not require interruption of flow in the recipient artery. By means of a suction device ("Octopus"), in 31 pigs the epicardium was grasped and immobilized through an arm contraption fixed to the operating table. In the first 15 consecutive pigs (study I), the two-dimensional motion of an epicardial beacon was monitored. In 16 subsequent pigs (study II), an internal mammary artery was grafted under the microscope in two steps to a proximal coronary artery segment, without cardiopulmonary bypass. First, the internal mammary artery was sutured end-to-side to the outside of the coronary artery. Secondly, an orifice was punched in the partitioning coronary wall by an excimer laser catheter introduced through a temporary side-branch of the internal mammary artery. Study II: During 43 suction periods in four anastomosis areas, immobilization was achieved for 15 to 169 min (>30 h in total) in 13 open- and 9 closed-chest procedures without hemodynamic deterioration. The area circumscribed by the edges of the beacon trajectory (area in which the anastomosis is to be tracked) was reduced from 73.0 +/- 43.0 mm(2) (mean +/- SD) to 1.3 +/- 0.5 mm(2) (p<0.001) in the open-chest and to 0.2 +/- 0.2 mm(2) in the closed-chest procedure. At 6 weeks, no myocardial or coronary suction lesions were found. Study II: Nonocclusive anastomosis surgery required 25 +/- 3 min. No leakage, serious arrhythmias, graft closure or hemodynamic deterioration occurred during the procedure or for 2 h after ligating the coronary artery proximally. At 6 weeks, all seven grafts were patent. Coronary bypass on the beating heart without interruption of coronary flow is feasible. In both open- and in closed-chest procedures, the "Octopus" reduced

  5. [Contribution of hemodynamic disturbances in magistral vessels to optic neuropathy progression and ocular tension changes in endocrine ophthalmopathy].

    Likhvantseva, V G; Kharlap, S I; Korosteleva, E V; Solomatina, M V; Mel'nikova, M V; Budanova, S V; Regeb, A Ben; Vygodin, V A

    2015-01-01

    to investigate the contribution of various hemodynamic disturbances in magistral vessels to optic neuropathy (ON) progression and ocular tension changes in endocrine ophthalmopathy (EOP). A total of 39 patients (78 eyes) with subclinical EOP (clinical activity score, CAS ≤ 2) associated with Graves' disease (n = 32, 64 eyes) or autoimmune thyroiditis (n = 7, 14 eyes) were examined. Orbit echography was performed in all patients. Blood flow was assessed with a Voluson 730 PRO ultrasound diagnostic system ("Kretz", Austria) in triplex mode (B-scan, color Doppler flow mapping in combination with pulse-wave Doppler). Thus obtained hemodynamic parameters in ophthalmic artery, central retinal artery (CRA), central retinal vein (CRV), short posterior ciliary arteries (SPCA), and long posterior ciliary arteries (LPCA) were analyzed. To reveal the role of hemodynamic disturbances in the above mentioned vessels in ON progression and eye pressure maintenance, the patients were divided into 7 groups. Only those eyes, whose peripheral indices were increased by more than 25% of normal values and diastolic blood flow decreased by not less than 25%, were selected for further study. Intraocular pressure changes were evaluated by group mean (Mmean = M ± m mmHg), optic neuropathy progression--by the difference in group mean depth (dB) and number of scotomas between the first and the last visit (6 months of observation). In almost all types of perfusion disturbances, the resultant chronic ocular ischemia causes a decrease in IOP. The only exception, as shown, is simultaneous involvement of CRA, SPCA, and LPCA. The level of blood flow disturbance determines the severity of qualitative and quantitative changes in eyes with EOP-associated ON. The rate of ON progression directly correlates with baseline IOP values on day zero. Long-lasting chronic impairment of blood supply of the eyeball leads to reduction in ocular tension and progression of optic neuropathy. Combined perfusion

  6. Comparison of myocardial blood flow induced by adenosine triphosphate and dipyridamole in patients with coronary artery disease

    Mamede, M.; Tadamura, Eiji; Hosokawa, Ryohei

    2005-01-01

    Myocardial perfusion imaging with adenosine triphosphate (ATP) has been used increasingly to diagnose coronary artery disease (CAD) and assess risk for this disease. This study compared absolute myocardial blood flow (MBF) and myocardial flow reserve index (MFR) with ATP and dipyridamole (DIP) in patients with CAD. MBF was quantified by 15 O-H 2 O PET in 21 patients with CAD (17 male, 4 female), aged 55 to 81 years. MBF was measured at rest, during intravenous injection of ATP (0.16 mg/kg/min), and again after DIP infusion (0.56 mg/kg). Regions of interest were drawn in nonischemic and ischemic segments based on findings from thallium-201 ( 201 Tl) scintigraphy and coronary angiography (CAG). Absolute MBF values and indexes of MFR were calculated in nonischemic and ischemic segments. Intravenous injection of ATP and DIP significantly increased MBF in nonischemic (2.4±0.9 and 2.1±0.8 ml/g/min, respectively; p<0.01, for both) and in ischemic segments (1.3±0.4 and 1.5±0.4 ml/g/min, respectively; p<0.01, for both). There was a significant difference in MBF values between ATP and DIP in nonischemic segments (p<0.05), which was not observed in ischemic segments. In nonischemic segments, ATP produced higher MFR than DIP (2.1±0.8 and 1.8±0.7, respectively; p<0.05), while no significant difference was observed in ischemic segments (1.5±0.6 and 1.7±0.3, respectively). ATP produced a greater hyperemia than DIP between the ischemic and nonischemic myocardium in patients with CAD. ATP is as effective as DIP for the diagnosis of CAD. (author)

  7. Near-infrared spectroscopy measurement of the pulsatile component of cerebral blood flow and volume from arterial oscillations

    Themelis, George; D'Arceuil, Helen; Diamond, Solomon G.; Thaker, Sonal; Huppert, Theodore J.; Boas, David A.

    2009-01-01

    We describe a near-infrared spectroscopy (NIRS) method to noninvasively measure relative changes in the pulsate components of cerebral blood flow (pCBF) and volume (pCBV) from the shape of heartbeat oscillations. We present a model that is used and data to show the feasibility of the method. We use a continuous-wave NIRS system to measure the arterial oscillations originating in the brains of piglets. Changes in the animals' CBF are induced by adding CO2 to the breathing gas. To study the influence of scalp on our measurements, comparative, invasive measurements are performed on one side of the head simultaneously with noninvasive measurements on the other side. We also did comparative measurements of CBF using a laser Doppler system to validate the results of our method. The results indicate that for sufficient source-detector separation, the signal contribution of the scalp is minimal and the measurements are representative of the cerebral hemodynamics. Moreover, good correlation between the results of the laser Doppler system and the NIRS system indicate that the presented method is capable of measuring relative changes in CBF. Preliminary results show the potential of this NIRS method to measure pCBF and pCBV relative changes in neonatal pigs. PMID:17343508

  8. Roles of myocardial blood volume and flow in coronary artery disease: an experimental MRI study at rest and during hyperemia

    McCommis, Kyle S.; Goldstein, Thomas A.; Pilgram, Thomas; Abendschein, Dana R.; Misselwitz, Bernd; Gropler, Robert J.; Zheng, Jie

    2010-01-01

    To validate fast perfusion mapping techniques in a setting of coronary artery stenosis, and to further assess the relationship of absolute myocardial blood volume (MBV) and blood flow (MBF) to global myocardial oxygen demand. A group of 27 mongrel dogs were divided into 10 controls and 17 with acute coronary stenosis. On 1.5-T MRI, first-pass perfusion imaging with a bolus injection of a blood-pool contrast agent was performed to determine myocardial perfusion both at rest and during either dipyridamole-induced vasodilation or dobutamine-induced stress. Regional values of MBF and MBV were quantified by using a fast mapping technique. Color microspheres and 99m Tc-labeled red blood cells were injected to obtain respective gold standards. Microsphere-measured MBF and 99m Tc-measured MBV reference values correlated well with the MR results. Given the same changes in MBF, changes in MBV are twofold greater with dobutamine than with dipyridamole. Under dobutamine stress, MBV shows better association with total myocardial oxygen demand than MBF. Coronary stenosis progressively reduced this association in the presence of increased stenosis severity. MR first-pass perfusion can rapidly estimate regional MBF and MBV. Absolute quantification of MBV may add additional information on stenosis severity and myocardial viability compared with standard qualitative clinical evaluations of myocardial perfusion. (orig.)

  9. Roles of myocardial blood volume and flow in coronary artery disease: an experimental MRI study at rest and during hyperemia

    McCommis, Kyle S.; Goldstein, Thomas A.; Abendschein, Dana R.; Misselwitz, Bernd; Pilgram, Thomas; Gropler, Robert J.

    2010-01-01

    Objective To validate fast perfusion mapping techniques in a setting of coronary artery stenosis, and to further assess the relationship of absolute myocardial blood volume (MBV) and blood flow (MBF) to global myocardial oxygen demand. Methods A group of 27 mongrel dogs were divided into 10 controls and 17 with acute coronary stenosis. On 1.5-T MRI, first-pass perfusion imaging with a bolus injection of a blood-pool contrast agent was performed to determine myocardial perfusion both at rest and during either dipyridamole-induced vasodilation or dobutamine-induced stress. Regional values of MBF and MBV were quantified by using a fast mapping technique. Color microspheres and 99mTc-labeled red blood cells were injected to obtain respective gold standards. Results Microsphere-measured MBF and 99mTc-measured MBV reference values correlated well with the MR results. Given the same changes in MBF, changes in MBV are twofold greater with dobutamine than with dipyridamole. Under dobutamine stress, MBV shows better association with total myocardial oxygen demand than MBF. Coronary stenosis progressively reduced this association in the presence of increased stenosis severity. Conclusions MR first-pass perfusion can rapidly estimate regional MBF and MBV. Absolute quantification of MBV may add additional information on stenosis severity and myocardial viability compared with standard qualitative clinical evaluations of myocardial perfusion. PMID:20182731

  10. Effect of black tea consumption on brachial artery flow-mediated dilation and ischaemia-reperfusion in humans.

    Schreuder, Tim H A; Eijsvogels, Thijs M H; Greyling, Arno; Draijer, Richard; Hopman, Maria T E; Thijssen, Dick H J

    2014-02-01

    Tea consumption is associated with reduced cardiovascular risk. Previous studies found that tea flavonoids work through direct effects on the vasculature, leading to dose-dependent improvements in endothelial function. Cardioprotective effects of regular tea consumption may relate to the prevention of endothelial ischaemia-reperfusion (IR) injury. Therefore, we examined the effect of black tea consumption on endothelial function and the ability of tea to prevent IR injury. In a randomized, crossover study, 20 healthy subjects underwent 7 days of tea consumption (3 cups per day) or abstinence from tea. We examined brachial artery (BA) endothelial function via flow-mediated dilation (FMD), using high resolution echo-Doppler, before and 90 min after tea or hot water consumption. Subsequently, we followed a 20-min ischaemia and 20-min reperfusion protocol of the BA after which we measured FMD to examine the potential of tea consumption to protect against IR injury. Tea consumption resulted in an immediate increase in FMD% (pre-consumption: 5.8 ± 2.5; post-consumption: 7.2 ± 3.2; p FMD (p FMD. However, the impact of the IR protocol on FMD was not influenced by tea consumption. Therefore, the cardioprotective association of tea ingestion relates to a direct effect of tea on the endothelium in humans in vivo.

  11. Transthoracic ultrasonic tissue indices identify patients with severe left anterior descending artery stenosis. Correlation with fractional flow reserve. Pilot study.

    Dobrowolski, Piotr; Kowalski, Mirosław; Rybicka, Justyna; Lech, Agnieszka; Tyczyński, Paweł; Witkowski, Adam; Hoffman, Piotr

    2016-01-01

    The aim of this study was to evaluate the potential clinical application of ultrasonic tissue indices, with a focus on systolic strain (SS) and systolic strain rate (SSR) parameters derived from transthoracic echocardiography, in the assessment of left anterior descending artery (LAD) stenosis. The data of 30 patients with significant LAD stenosis were analysed. All patients underwent transthoracic echocardiography to obtain systolic myocardial velocity (Sm), longitudinal SS, and SSR from basal, mid, and apical segments of anterior and inferior walls in two-chamber apical view. Severity of LAD obstruction was measured by means of fractional flow reserve (FFR) during coronary catheterisation. Systolic velocities, strain, and strain rate measured in basal, middle, and apical segments of the anterior left ventricular (LV) wall were lower when compared to those obtained from the corresponding, i.e. unaffected, inferior LV wall. There was a significant correlation between FFR and the value of SS, SSR characterising the apical LV segment of the anterior wall (r = -0.583, p = 0.01; r = -0.598, p = 0.01, respectively). Moreover, we found significant correlation between FFR and Sm in the mid-segment of the LV anterior wall (r = 0.611, p = 0.009). We conclude that SS and SSR obtained from the apical segment of the anterior LV wall may be related to the severity of LAD stenosis.

  12. Various clinical scenarios leading to development of the string sign of the internal thoracic artery after coronary bypass surgery: the role of competitive flow, a case series

    Kolozsvari Rudolf

    2012-01-01

    Full Text Available Abstract Background The left internal mammary artery (LIMA is the choice for grafting of the left anterior descending coronary artery (LAD. One possible mechanism of the rare graft failure involve the presence of competitive flow. Method 105 patients who had undergone coronary bypass grafting between 1998 and 2000 were included in this observational study. The recatheterizations were performed 28 months after the operations. The rate of patency the LIMA grafts was determined, and the cases with graft failure were analyzed. Results The LIMA graft was patent in 99 patients (94%. Six patients (6% exhibited diffuse involution of the graft (string sign. The string sign was always associated with competitive flow as the basis of the LIMA graft involution. In one case quantitative re-evaluation of the preoperative coronary angiography revealed merely less than 50% diameter stenosis on the LAD with a nonligated side-branch of the LIMA. At recatheterization in two patients the pressure wire measurements demonstrated only a non-significant decrease of the fractional flow reserve (0.83 and 0.89, despite the 53% and 57% diameter stenosis in the angiogram. Another patient displayeda significant regression of the LAD lesion between the pre- and postoperative coronary angiography (from 76% to 44% as the cause of the development of the competitive flow. In one instance, a radial artery graft on the LAD during a redo bypass operation resulted in competitive flow in the radial graft due to the greater diameter than that of the LIMA. In a further patient, competitive flow developed from a short sequential part of the LIMA graft between the nonsignificantly stenosed diagonal branch and the LAD, with involution of the main part of the graft to the diagonal branch. Conclusions The most common cause of the development of the string sign of a LIMA graft due to competitive flow is overassessment of the lesion of the LAD. Regression of a previous lesion or some other

  13. Application of Micropore Filter Technology: Exploring the Blood Flow Path in Arterial-Line Filters and Its Effect on Bubble Trapping Functions.

    Herbst, Daniel P

    2017-03-01

    Conventional arterial-line filters commonly use a large volume circular shaped housing, a wetted micropore screen, and a purge port to trap, separate, and remove gas bubbles from extracorporeal blood flow. Focusing on the bubble trapping function, this work attempts to explore how the filter housing shape and its resulting blood flow path affect the clinical application of arterial-line filters in terms of gross air handling. A video camera was used in a wet-lab setting to record observations made during gross air-bolus injections in three different radially designed filters using a 30-70% glycerol-saline mixture flowing at 4.5 L/min. Two of the filters both had inlet ports attached near the filter-housing top with bottom oriented outlet ports at the bottom, whereas the third filter had its inlet and outlet ports both located at the bottom of the filter housing. The two filters with top-in bottom-out fluid paths were shown to direct the incoming flow downward as it passed through the filter, placing the forces of buoyancy and viscous drag in opposition to each other. This contrasted with the third filter's bottom-in bottom-out fluid path, which was shown to direct the incoming flow upward so that the forces of buoyancy and viscous drag work together. The direction of the blood flow path through a filter may be important to the application of arterial-line filter technology as it helps determine how the forces of buoyancy and flow are aligned with one another.

  14. Numerical modelling on pulsatile flow of Casson nanofluid through an inclined artery with stenosis and tapering under the influence of magnetic field and periodic body acceleration

    Ponalagusamy, R.; Priyadharshini, S.

    2017-11-01

    The present study investigates the pulsatile flow of Casson nanofluid through an inclined and stenosed artery with tapering in the presence of magnetic field and periodic body acceleration. The iron oxide nanoparticles are allowed to flow along with it. The governing equations for the flow of Casson fluid when the artery is tapered slightly having mild stenosis are highly non-linear and the momentum equations for temperature and concentration are coupled and are solved using finite difference numerical schemes in order to find the solutions for velocity, temperature, concentration, wall shear stress, and resistance to blood flow. The aim of the present study is to analyze the effects of flow parameters on the flow of nanofluid through an inclined arterial stenosis with tapering. These effects are represented graphically and concluded that the wall shear stress profiles enhance with increase in yield stress, magnetic field, thermophoresis parameter and decreases with Brownian motion parameter, local temperature Grashof number, local nanoparticle Grashof number. The significance of the model is the existence of yield stress and it is examined that when the rheology of blood changes from Newtonian to Casson fluid, the percentage of decrease in the flow resistance is higher with respect to the increase in the parameters local temperature Grashof number, local nanoparticle Grashof number, Brownian motion parameter, and Prandtl number. It is pertinent to observe that increase in the Brownian motion parameter leads to increment in concentration and temperature profiles. It is observed that the concentration of nanoparticles decreases with increase in the value of thermophoresis parameter.

  15. To assess the intimal thickness, flow velocities, and luminal diameter of carotid arteries using high-resolution B-mode ultrasound doppler imaging

    Vemuru, Madhuri; Jabbar, Afzal; Chandra, Suman

    2004-04-01

    Carotid imaging is a Gold Standard test that provides useful information about the structure and functions of carotid arteries. Spectral imaging helps to evaluate the vessel and hemodynamic changes. High resolution B-mode imaging has emerged as one of the methods of choice for determining the anatomic extent of atherosclerosis and its progression and for assessing cardiovascular risks. The measurements made with Doppler correlate well with pathologic measurements. Recent prospective studies have clearly demonstrated that these measurements of carotid intimal thickness are potent predictors of Myocardial Infarction and Stroke. This method appears very attractive as it is non-invasive, extremely safe, well accepted by the patient and relatively inexpensive. It can be performed serially and has the advantage of visualizing the arterial wall in contrast to angiographic techniques which provide only an outline of the arterial lumen. Recently, there has been an interest in the clinical use of this technique in making difficult clinical decisions like deciding on preventive therapies. 30 subjects aged 21-60 years and 30 subjects aged 61-85 years of both sexes are selected after doing a baseline study to exclude Hypertension, Diabetes, Obesity and Hyperlipidemia. The carotid arteries were examined for intimal thickening, blood flow velocities and luminal diameter. With aging there is a narrowing of the carotid vessels and significant increase in intimal thickening with a consequent increase in the blood flow velocities. Inter-observer, intra-observer and instrument variations are seen and there is no significant change in the values when the distal flow pattern is considered for measurements. Aging produces major cardiovascular changes including decreased elasticity and compliance of great arteries leading to structural and functional alterations in heart and vessels. With aging there is increased intimal thickness and increased pulse wave velocity which is clearly

  16. Distribution of the blood flow supplied by the vertebral artery in humans as assessed by emission CT

    Taki, W.; Handa, H.; Higa, T.; Tanada, S.; Fukuyama, H.; Fujita, T.; Yonekawa, Y.; Kameyama, M.; Torizuka, K.

    1984-01-01

    Though unilateral blood distribution of the vertebral artery has not been studied in humans, it is significant when considering the ischemic events especially embolic occlusion in vertebrobasilar system. To clarify the blood distribution, Krypton-81m was continuously infused into the vertebral arteries of 10 patients. Radioactivity was recorded by a rotating gamma camera. The perfusion images, reconstructed by computer in the transaxial plane, were classified according to whether the distribution was equal, or predominantly unilateral. Overlapping of blood supply from each vertebral artery was studied. In addition, the perfusion from one of the vertebral arteries revealed four distribution patterns with respect to laterality. A) ipsilateral; B) contralateral; C) bilateral; D) mosaic. Images obtained following perfusion of the vertebral artery show less uniformity compared to that of the internal carotid artery, suggesting a complicated vascular supply of the vertebral basilar territory. This complex distribution can be classified by the use of continuous infusion of Krypton-81m

  17. Rubidium-82 PET-CT for quantitative assessment of myocardial blood flow: validation in a canine model of coronary artery stenosis

    Lautamaeki, Riikka; Higuchi, Takahiro; Merrill, Jennifer; Voicu, Corina; Bengel, Frank M.; George, Richard T.; Kitagawa, Kakuya; DiPaula, Anthony; Lima, Joao A.C.; Nekolla, Stephan G.; Lardo, Albert C.

    2009-01-01

    Absolute quantification of myocardial blood flow expands the diagnostic potential of PET for assessment of coronary artery disease. 82 Rb has significantly contributed to increasing utilization of PET; however, clinical studies are still mostly analysed qualitatively. The aim of this study was to reevaluate the feasibility of 82 Rb for flow quantification, using hybrid PET-CT in an animal model of coronary stenosis. Nine dogs were prepared with experimental coronary artery stenosis. Dynamic PET was performed for 8 min after 82 Rb(1480-1850 MBq) injection during adenosine-induced vasodilation. Microspheres were injected simultaneously for reference flow measurements. CT angiography was used to determine the myocardial regions related to the stenotic vessel. Two methods for flow calculation were employed: a two-compartment model including a spill-over term, and a simplified retention index. The two-compartment model data were in good agreement with microsphere flow (y=0.84x+0.20; r=0.92, p 82 Rb. A simplified approach based on tracer retention is practicable in the physiological flow range. These results encourage further testing of the robustness and usefulness in the clinical context of cardiac hybrid imaging. (orig.)

  18. Rubidium-82 PET-CT for quantitative assessment of myocardial blood flow: validation in a canine model of coronary artery stenosis

    Lautamaeki, Riikka; Higuchi, Takahiro; Merrill, Jennifer; Voicu, Corina; Bengel, Frank M. [Johns Hopkins Medical Institutions, Department of Radiology, Division of Nuclear Medicine, Baltimore, MD (United States); George, Richard T.; Kitagawa, Kakuya; DiPaula, Anthony; Lima, Joao A.C. [Johns Hopkins Medical Institutions, Department of Medicine, Division of Cardiology, Baltimore, MD (United States); Nekolla, Stephan G. [Technischen Universitaet Muenchen, Nuklearmedizinische Klinik und Poliklinik, Klinikum rechts der Isar, Munich (Germany); Lardo, Albert C. [Johns Hopkins Medical Institutions, Department of Medicine, Division of Cardiology, Baltimore, MD (United States); Johns Hopkins Medical Institutions, Department of Biomedical Engineering, Baltimore, MD (United States)

    2009-04-15

    Absolute quantification of myocardial blood flow expands the diagnostic potential of PET for assessment of coronary artery disease. {sup 82}Rb has significantly contributed to increasing utilization of PET; however, clinical studies are still mostly analysed qualitatively. The aim of this study was to reevaluate the feasibility of {sup 82}Rb for flow quantification, using hybrid PET-CT in an animal model of coronary stenosis. Nine dogs were prepared with experimental coronary artery stenosis. Dynamic PET was performed for 8 min after {sup 82}Rb(1480-1850 MBq) injection during adenosine-induced vasodilation. Microspheres were injected simultaneously for reference flow measurements. CT angiography was used to determine the myocardial regions related to the stenotic vessel. Two methods for flow calculation were employed: a two-compartment model including a spill-over term, and a simplified retention index. The two-compartment model data were in good agreement with microsphere flow (y=0.84x+0.20; r=0.92, p<0.0001), although there was variability in the physiological flow range <3 ml/g per minute (y=0.54x+0.53; r=0.53, p=0.042). Results from the retention index also correlated well with microsphere flow (y=0.47x+0.52; r=0.75, p=0.0004). Error increased with higher flow, but the correlation was good in the physiological range (y=0.62x+0.29; r=0.84, p=0.0001). Using current state-of-the-art PET-CT systems, quantification of myocardial blood flow is feasible with {sup 82}Rb. A simplified approach based on tracer retention is practicable in the physiological flow range. These results encourage further testing of the robustness and usefulness in the clinical context of cardiac hybrid imaging. (orig.)

  19. Nonenhanced magnetic resonance angiography (MRA) of the calf arteries at 3 Tesla: intraindividual comparison of 3D flow-dependent subtractive MRA and 2D flow-independent non-subtractive MRA

    Knobloch, Gesine; Lauff, Marie-Teres; Hirsch, Sebastian; Hamm, Bernd; Wagner, Moritz [Charite - Universitaetsmedizin Berlin, Department of Radiology, Berlin (Germany); Schwenke, Carsten [SCO:SSiS Statistical Consulting, Berlin (Germany)

    2016-12-15

    To prospectively compare 3D flow-dependent subtractive MRA vs. 2D flow-independent non-subtractive MRA for assessment of the calf arteries at 3 Tesla. Forty-two patients with peripheral arterial occlusive disease underwent nonenhanced MRA of calf arteries at 3 Tesla with 3D flow-dependent subtractive MRA (fast spin echo sequence; 3D-FSE-MRA) and 2D flow-independent non-subtractive MRA (balanced steady-state-free-precession sequence; 2D-bSSFP-MRA). Moreover, all patients underwent contrast-enhanced MRA (CE-MRA) as standard-of-reference. Two readers performed a per-segment evaluation for image quality (4 = excellent to 0 = non-diagnostic) and severity of stenosis. Image quality scores of 2D-bSSFP-MRA were significantly higher compared to 3D-FSE-MRA (medians across readers: 4 vs. 3; p < 0.0001) with lower rates of non-diagnostic vessel segments on 2D-bSSFP-MRA (reader 1: <1 % vs. 15 %; reader 2: 1 % vs. 29 %; p < 0.05). Diagnostic performance of 2D-bSSFP-MRA and 3D-FSE-MRA across readers showed sensitivities of 89 % (214/240) vs. 70 % (168/240), p = 0.0153; specificities: 91 % (840/926) vs. 63 % (585/926), p < 0.0001; and diagnostic accuracies of 90 % (1054/1166) vs. 65 % (753/1166), p < 0.0001. 2D flow-independent non-subtractive MRA (2D-bSSFP-MRA) is a robust nonenhanced MRA technique for assessment of the calf arteries at 3 Tesla with significantly higher image quality and diagnostic accuracy compared to 3D flow-dependent subtractive MRA (3D-FSE-MRA). (orig.)

  20. Changes in CT angiographic opacification of porcine coronary artery wall with patchy altered flow in vasa vasorum.

    Moritz, Regina; Anderson, Jill L; Vercnocke, Andrew J; Wentz, Robert J; Ritman, Erik L

    2013-08-01

    To evaluate the potential of whole-body CT to detect localized areas of decreased or increased vascularity in coronary arterial walls. We used both microsphere embolization of coronary artery vasa vasorum to generate small areas of hypoperfusion and surrounding hyperperfusion of the arterial wall and diet-induced hypercholesterolemia. As a stimulus for localized angiogenesis, such as occurs in early plaque formation in the coronary arterial wall, microspheres were injected selectively into the LAD coronary artery lumens of anesthetized pigs. Fourteen pigs (acute) then had a segment of their LAD harvested during injection of contrast medium and snap-frozen for subsequent cryo-static micro-CT. An additional thirteen pigs (chronic) were allowed to recover, fed a high cholesterol diet and 3 months later were again anesthetized and a segment of the LAD artery harvested and scanned. The spatial distribution of the contrast agent within the arterial wall was measured in contiguous micro-CT images at right angles to the lumen axis with the area of wall in each cross-sectional image being approximately (0.1 mm)(3) in size. In the acute animals there were no localized areas of increased contrast around the hypoperfused embolized perfusion territories in the arterial wall, but in the chronic animals the hypoperfused areas were surrounded by increased contrast. These results suggest that CT might be able to detect localized regions of increased vascularity in the arterial wall as an indicator of early atherosclerotic stimulation of vasa vasorum proliferation.

  1. Ocular manifestations of leptospirosis

    Rathinam S

    2005-01-01

    Full Text Available Leptospiral uveitis is a common entity in tropical countries. Ocular manifestations are noted in the second phase of illness, but these remain under-diagnosed mainly because of the prolonged symptom-free period that separates the systemic manifestations from detection of ocular manifestations.Varying ophthalmic presentations and the intrinsic nature of different types of uveitis to mimic one another also challenge the accuracy of the diagnosis. Of the individual ocular signs, the combination of acute, non-granulomatous, panuveitis, hypopyon, vasculitis, optic disc edema, membranous vitreous opacities and absence of choroiditis or retinitis have high predictive value for the clinical diagnosis of leptospiral uveitis. Geographic location of the patient, occupation, socio-economic status, risk factors related to exposure, past history of fever or jaundice also aid in diagnosis.Steroids are the mainstay of treatment for leptospiral uveitis. Depending upon the severity and anatomical location of inflammatory lesion, topical, peri-ocular and/or systemic steroids are given. The prognosis is generally good, even when the inflammation is severe.

  2. Ocular straylight in albinism

    Kruijt, Bastiaan; Franssen, Luuk; Prick, Liesbeth J. J. M.; van Vliet, Johannes M. J.; van den Berg, Thomas J. T. P.

    2011-01-01

    Albinism is an inherited disorder that affects the melanin biosynthesis pathway, which results in reduced or absent pigment formation. This may lead to increased light transmission through the iris and more reflected light from the fundus. Both these effects contribute to the occurrence of ocular

  3. Therapy of ocular toxoplasmosis

    Rothova, A.; Buitenhuis, H. J.; Meenken, C.; Baarsma, G. S.; Boen-Tan, T. N.; de Jong, P. T.; Schweitzer, C. M.; Timmerman, Z.; de Vries, J.; Zaal, M. J.

    1989-01-01

    We performed a prospective multicentre study to evaluate the efficacy of therapeutic strategies currently used for ocular toxoplasmosis in a large number of patients (n = 106). Treatment was given for at least four weeks and consisted of three triple drug combinations: group 1, pyrimethamine,

  4. The impact of menstrual phase on brachial artery flow-mediated dilatation during handgrip exercise in healthy premenopausal women.

    D'Urzo, Katrina A; King, Trevor J; Williams, Jennifer S; Silvester, Morgan D; Pyke, Kyra E

    2018-02-01

    What is the central question of this study? The aim of this study was to determine the influence of menstrual phase on flow-mediated dilatation in response to sustained, exercise-induced increases in shear stress. What is the main finding and its importance? We showed, for the first time, that in healthy, premenopausal women the flow-mediated dilatation stimulated by exercise-induced increases in shear stress did not fluctuate across two phases of the menstrual cycle, despite significant fluctuations in oestrogen. This suggests that endothelial function is not consistently augmented in the high-oestrogen phase. Flow-mediated dilatation (FMD) in response to a sustained shear-stress stimulus (e.g. via handgrip exercise; HGEX) is emerging as a useful tool for assessing endothelial function; however, the impact of menstrual phase on HGEX-FMD is unknown. The purpose of this study was to determine whether HGEX-FMD fluctuates with cyclical changes in oestrogen concentrations over two discrete phases (low and high oestrogen) of the menstrual cycle. Brachial artery (BA) diameter and blood velocity were assessed with two-dimesional and Doppler ultrasound, respectively. Shear stress was estimated using shear rate (SR = BA blood velocity/BA diameter). Participants (12 healthy, regularly cycling women, 21 ± 2 years of age) completed two experimental visits: (i) low oestrogen (early follicular, EF); and (ii) high oestrogen (late follicular, LF). Reactive hyperaemia-stimulated FMD (RH-FMD) and HGEX-FMD (6 min of handgrip exercise) were assessed during each visit. Results are mean values ± SD. Oestrogen increased from the EF to LF phase (EF, 33 ± 9 pg ml -1 ; LF, 161 ± 113 pg ml -1 , P = 0.003). However, neither the SR stimuli (HGEX, P = 0.501; RH, P = 0.173) nor the FMD responses differed between phases (EF versus LF: HGEX-FMD, 4.8 ± 2.8 versus 4.6 ± 2.2%, P = 0.601; RH-FMD, 7.9 ± 4.3 versus 6.4 ± 3.1%, P = 0.071). These results extend

  5. Relationship between ocular surface temperature and peripheral vasoconstriction in healthy subjects: A thermographic study

    Matteoli, Sara; Vannetti, Federica; Finocchio, Lucia

    2014-01-01

    An impairment of ocular blood flow regulation is commonly considered one of the main pathogenetic mechanisms involved in the development of several eye diseases, like glaucoma. The aim of this study was to investigate whether an alteration of ocular blood supply induced by peripheral vasoconstric......An impairment of ocular blood flow regulation is commonly considered one of the main pathogenetic mechanisms involved in the development of several eye diseases, like glaucoma. The aim of this study was to investigate whether an alteration of ocular blood supply induced by peripheral...

  6. Relationship between signal intensity of blood flow in the pulmonary artery obtained by magnetic resonance imaging and results of right cardiac catheterization in patients with pulmonary disease

    Yuguchi, Yasutoshi; Nagao, Keiichi; Kouno, Norihiro; Tanabe, Nobuhiro; Okita, Shinya; Tojima, Hirokazu; Okada, Osamu; Kuriyama, Takayuki [Chiba Univ. (Japan). School of Medicine; Yamaguchi, Tetsuo

    1992-08-01

    Electrocardiogram-gated spin-echo magnetic resonance (MR) images of the chest were obtained in five normal controls and 35 patients with pulmonary disease (11 chronic obstructive pulmonary disease, 6 pulmonary thromboembolism, 5 primary pulmonary hypertension, 4 interstitial pulmonary disease, 4 pulmonary hypertension with disturbance of portal circulation, and 5 other diseases) who underwent right cardiac catheterization. In transverse images at the level of the right main pulmonary artery (rPA) and sagittal images at the level through the midsternal line and the spinal cord, the signal intensity of blood flow in the rPA was quantitatively evaluated, and the correlations with the MR signal intensity of intravascular flow and the parameters of hemodynamics were studied. In diastole MR images of both normal controls and patients mostly showed a significant signal and visible flow images. In systolic MR images, the mean values of hemodynamic parameters (mean pulmonary arterial pressure (mPAP), pulmonary arteriolar resistance (PAR), and cardiac index (CI)) were abnormal in patients with significant signal intensity of flow compared with those in patients without sufficient MR signal. The signal intensity was not correlated with mPAP; however, it significantly increased as PAR increased, and it increased as CI decreased both in diastole and in systole. Especially in systole, there was good correlation between the signal intensity in transverse MR images and CI and between signal intensity in sagittal MR images and PAR . These results suggest that the signal intensity of blood flow in the rPA on MR images can be used as an index of the severity of right heart failure associated with pulmonary disease. MR imaging is a useful modality to evaluate pulmonary circulation disturbance because of its ability to assess blood flow in the pulmonary artery noninvasively without interference from other structures such as bone and normal lung. (J.P.N.).

  7. A fast analysis method for non-invasive imaging of blood flow in individual cerebral arteries using vessel-encoded arterial spin labelling angiography

    Chappell,