scholarly journals Synchronization of Wave Flows of Arterial and Venous Blood and Phases of the Cardiac Cycle: Part 4

2019 ◽  
Vol 9 (2) ◽  
pp. 106-110
Author(s):  
Alexander Kruglov ◽  
Valery Utkin ◽  
Alexander Vasilyev ◽  
Andrey Kruglov
Keyword(s):  
Cardiac Cycle ◽  
Venous Blood ◽  
Wave Flows

scholarly journals Synchronization of Wave Flows of Arterial and Venous Blood and Phases of the Cardiac Cycle with the Structure of the Peripheral Pulse Wave in Norm: Part 2

2018 ◽  
Vol 8 (3) ◽  
pp. 177-181
Author(s):  
Alexander Kruglov ◽  
◽  
Valery Utkin ◽  
Alexander Vasilyev ◽  
Andrey Kruglov ◽  
...  
Keyword(s):  
Cardiac Cycle ◽  
Pulse Wave ◽  
Venous Blood ◽  
Peripheral Pulse ◽  
Wave Flows

scholarly journals Synchronization of Wave Flows of Arterial and Venous Blood and Phases of the Cardiac Cycle: Part 3

2018 ◽  
Vol 8 (4) ◽  
pp. 288-291
Author(s):  
Alexander Kruglov ◽  
Valery Utkin ◽  
Alexander Vasilyev ◽  
Andrey Kruglov
Keyword(s):  
Cardiac Cycle ◽  
Venous Blood ◽  
Wave Flows

scholarly journals Synchronization of Wave Flows of Arterial and Venous Blood with Phases of the Cardiac Cycle in Norm: Part 1

2018 ◽  
Vol 8 (2) ◽  
pp. 123-128
Author(s):  
Alexander Kruglov ◽  
Valery Utkin ◽  
Alexander Vasilyev
Keyword(s):  
Cardiac Cycle ◽  
Venous Blood ◽  
Wave Flows

Noninvasive intracranial compliance and pressure based on dynamic magnetic resonance imaging of blood flow and cerebrospinal fluid flow: review of principles, implementation, and other noninvasive approaches

2003 ◽  
Vol 14 (4) ◽  
pp. 1-8 ◽  
Author(s):  
Patricia B. Raksin ◽  
Noam Alperin ◽  
Anusha Sivaramakrishnan ◽  
Sushma Surapaneni ◽  
Terry Lichtor
Keyword(s):  
Magnetic Resonance Imaging ◽  
Cerebrospinal Fluid ◽  
Magnetic Resonance ◽  
Cardiac Cycle ◽  
Venous Blood ◽  
Pressure Probe ◽  
Intracranial Volume ◽  
Resonance Imaging ◽  
Intracranial Compliance ◽  
Arterial Blood

Current techniques for intracranial pressure (ICP) measurement are invasive. All require a surgical procedure for placement of a pressure probe in the central nervous system and, as such, are associated with risk and morbidity. These considerations have driven investigators to develop noninvasive techniques for pressure estimation. A recently developed magnetic resonance (MR) imaging–based method to measure intracranial compliance and pressure is described. In this method the small changes in intracranial volume and ICP that occur naturally with each cardiac cycle are considered. The pressure change during the cardiac cycle is derived from the cerebrospinal fluid (CSF) pressure gradient waveform calculated from the CSF velocities. The intracranial volume change is determined by the instantaneous differences between arterial blood inflow, venous blood outflow, and CSF volumetric flow rates into and out of the cranial vault. Elastance (the inverse of compliance) is derived from the ratio of the measured pressure and volume changes. A mean ICP value is then derived based on a linear relationship that exists between intracranial elastance and ICP. The method has been validated in baboons, flow phantoms, and computer simulations. To date studies in humans demonstrate good measurement reproducibility and reliability. Several other noninvasive approaches for ICP measurement, mostly nonimaging based, are also reviewed. Magnetic resonance imaging–based ICP measurement may prove valuable in the diagnosis and serial evaluation of patients with a variety of disorders associated with alterations in ICP.

scholarly journals Portable, non-invasive video imaging of retinal blood flow dynamics

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Kyoung-A Cho ◽  
Abhishek Rege ◽  
Yici Jing ◽  
Akash Chaurasia ◽  
Amit Guruprasad ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cardiac Cycle ◽  
Venous Blood ◽  
Retinal Blood Flow ◽  
High Temporal Resolution ◽  
Venous Blood Flow ◽  
Head Region ◽  
Flow Measurements ◽  
Non Invasive ◽  
Temporal Waveform

AbstractRetinal blood flow (RBF) information has the potential to offer insight into ophthalmic health and disease that is complementary to traditional anatomical biomarkers as well as to retinal perfusion information provided by fluorescence or optical coherence tomography angiography (OCT-A). The present study was performed to test the functional attributes and performance of the XyCAM RI, a non-invasive imager that obtains and assesses RBF information. The XyCAM RI was installed and used in two different settings to obtain video recordings of the blood flow in the optic nerve head region in eyes of healthy subjects. The mean blood flow velocity index (BFVi) in the optic disc and in each of multiple arterial and venous segments was obtained and shown to reveal a temporal waveform with a peak and trough that correlates with a cardiac cycle as revealed by a reference pulse oximeter (correlation between respective peak-to-peak distances was 0.977). The intra-session repeatability of the XyCAM RI was high with a coefficient of variation (CV) of 1.84 ± 1.13% across both sites. Artery-vein comparisons were made by estimating, in a pair of adjacent arterial and venous segments, various temporal waveform metrics such as pulsatility index, percent time in systole and diastole, and change in vascular blood volume over a cardiac cycle. All arterial metrics were shown to have significant differences with venous metrics (p < 0.001). The XyCAM RI, therefore, by obtaining repeatable blood flow measurements with high temporal resolution, permits the differential assessment of arterial and venous blood flow patterns in the retina that may facilitate research into disease pathophysiology and biomarker development for diagnostics.

Ultrastructure of rat alveolar macrophages activated in situ by poly:IC

1987 ◽  
Vol 45 ◽  
pp. 768-769
Author(s):  
A. M. Klinkner ◽  
R. A. Weiss ◽  
A. Kelley ◽  
P. J. Bugelski
Keyword(s):  
Venous Blood ◽  
Intratracheal Instillation ◽  
Buffy Coat ◽  
Fischer 344 Rats ◽  
Blood Monocytes ◽  
Fischer 344 ◽  
Polyinosinic:Polycytidylic Acid ◽  
Macrophage Activator ◽  
Endogenous Peroxidase

Polyinosinic:polycytidylic acid is an inducer of interferon and a macrophage activator. We have found that intratracheal instillation of polyI:C (IT-pI:C) activates rat bronchoalveolar lavage cells (BAL) for a variety of functions. Examination of Giemsa stained, cytocentrifuge preparations showed that IT-pI:C induced a population of BAL not seen in resident BAL. The morphology of these cells suggested that they might be derived from blood monocytes. To test this hypothesis we have examined several populations of macrophages that had been stained for endogenous peroxidase activity as a marker of cells derived from the monocyte-macrophage lineage.Macrophages were obtained from Fischer 344 rats. Peritoneal exudate cells (PEC) were collected by lavage 4 days after i.p. injection of 20 ml 3% thioglycolate. Buffy coat monocytes were separated from venous blood from naive rats.

Assessment of the incorporation of revascularized fibula grafts used for mandibular reconstruction with F-18-PET

2001 ◽  
Vol 40 (02) ◽  
pp. 51-58 ◽  
Author(s):  
H. Schliephake ◽  
van den Hoff ◽  
W. H. Knapp ◽  
G. Berding
Keyword(s):  
Blood Flow ◽  
Regional Blood Flow ◽  
Venous Blood ◽  
Mandibular Reconstruction ◽  
Reference Region ◽  
Osteoblastic Activity ◽  
Non Union ◽  
Range Of Values ◽  
Measured Input

Summary Aim: Determination of the range of regional blood flow and fluoride influx during normal incorporation of revascularized fibula grafts used for mandibular reconstruction. Evaluation, if healing complications are preceded by typical deviations of these parameters from the normal range. Assessment of the potential influence of using “scaled population-derived” instead of “individually measured” input functions in quantitative analysis. Methods: Dynamic F-l 8-PET images and arterialized venous blood samples were obtained in 11 patients early and late after surgery. Based on kinetic modeling regional blood flow (K1) and fluoride influx (Kmlf) were determined. Results: In uncomplicated cases, early postoperative graft K1 - but not Kmlf -exceeded that of vertebrae as reference region. Kmn values obtained in graft necrosis (n = 2) were below the ranges of values observed in uncomplicated healing (0.01 13-0.0745 ml/min/ml) as well as that of the reference region (0.0154-0.0748). Knf values in mobile non-union were in the lower range - and those in rigid non-union in the upper range of values obtained in stable union (0.021 1-0.0694). If scaled population-derived instead of measured input functions were used for quantification, mean deviations of 23 ± 17% in K1 and 12 ± 16% in Kmlf were observed. Conclusions: Normal healing of predominantly cortical bone transplants is characterized by relatively low osteoblastic activity together with increased perfusion. It may be anticipated that transplant necrosis can be identified by showing markedly reduced F− influx. In case that measured input functions are not available, quantification with scaled population-derived input functions is appropriate if expected differences in quantitative parameters exceed 70%.

Assessment of Myocardial Viability in Persistent Defects on Thallium-201 SPECT after Reinjection Using Gradient-Echo MRI

1996 ◽  
Vol 35 (05) ◽  
pp. 146-152 ◽  
Author(s):  
A. Kögler ◽  
H.-A. Schmitt ◽  
D. Emrich ◽  
H. Kreuzer ◽  
D. L. Munz ◽  
...  
Keyword(s):  
Wall Thickness ◽  
Myocardial Viability ◽  
Cardiac Cycle ◽  
Single Photon ◽  
Contractile Function ◽  
Left Ventricular ◽  
Wall Thickening ◽  
Gradient Echo ◽  
Systolic Wall Thickening

SummaryThis prospective study assessed myocardial viability in 30 patients with coronary heart disease and persistent defects despite reinjection on TI-201 single-photon computed tomography (SPECT). In each patient, three observers graded TI-201 uptake in 7 left ventricular wall segments. Gradient-echo magnetic resonance imaging in the region of the persistent defect generated 12 to 16 short axis views representing a cardiac cycle. A total of 120 segments were analyzed. Mean end-diastolic wall thickness and systolic wall thickening (± SD) was 11.5 ± 2.7 mm and 5.8 ± 3.9 mm in 48 segments with normal TI-201 uptake, 10.1 ± 3.4 mm and 3.7 ± 3.1 mm in 31 with reversible lesions, 11.3 ± 2.8 mm and 3.3 ± 1.9 mm in 10 with mild persistent defects, 9.2 ± 2.9 mm and 3.2 ±2.2 mm in 15 with moderate persistent defects, 5.8 ± 1.7 mm and 1.3 ± 1.4 mm in 16 with severe persistent defects, respectively. Significant differences in mean end-diastolic wall thickness (p <0.0005) and systolic wall thickening (p <0.005) were found only between segments with severe persistent defects and all other groups, but not among the other groups. On follow-up in 11 patients after revascularization, 6 segments with mild-to-moderate persistent defects showed improvement in mean systolic wall thickening that was not seen in 6 other segments with severe persistent defects. These data indicate that most myocardial segments with mild and moderate persistent TI-201 defects after reinjection still contain viable tissue. Segments with severe persistent defects, however, represent predominantly nonviable myocardium without contractile function.

Sign in / Sign up

Export Citation Format

Share Document