scholarly journals Analysis of Contact Stability and Contact Safety of a Robotic Intravascular Cardiac Catheter under Blood Flow Disturbances

2020 ◽  
Author(s):  
Ran Hao ◽  
Nate Lombard Poirot ◽  
M. Cenk Cavusoglu
Keyword(s):  
Blood Flow ◽  
Cardiac Catheter ◽  
Flow Disturbances ◽  
Contact Stability

A Probabilistic Approach for Contact Stability and Contact Safety Analysis of Robotic Intracardiac Catheter

2021 ◽  
Author(s):  
Ran Hao ◽  
M. Cenk Cavusoglu
Keyword(s):  
Blood Flow ◽  
Main Pulmonary Artery ◽  
Probabilistic Approach ◽  
Surface Motion ◽  
Flow Disturbances ◽  
Contact Stability ◽  
Cardiac Catheters ◽  
Heart Motion ◽  
Tissue Surface ◽  
Safety Metrics

Abstract The disturbances caused by the blood flow and tissue surface motions are major concerns during the motion planning of a intracardiac robotic catheter. Maintaining a stable and safe contact on the desired ablation point is essential for achieving effective lesions during the ablation procedure. In this paper, a probabilistic formulation of the contact stability and the contact safety for intravascular cardiac catheters under the blood flow and surface motion disturbances is presented. Probabilistic contact stability and contact safety metrics, employing a sample based representation of the blood flow velocity distribution and the heart motion trajectory, are introduced. Finally, the contact stability and safety for a MRI-actuated robotic catheter under main pulmonary artery blood flow disturbances and left ventricle surface motion disturbances are analyzed in simulation as example scenarios.

scholarly journals Age-Dependent Cerebrovascular Abnormalities and Blood Flow Disturbances in APP23 Mice Modeling Alzheimer's Disease

2003 ◽  
Vol 23 (24) ◽  
pp. 8453-8459 ◽  
Author(s):  
Nicolau Beckmann ◽  
Alexandra Schuler ◽  
Thomas Mueggler ◽  
Eric P. Meyer ◽  
Karl-Heinz Wiederhold ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Blood Flow ◽  
Flow Disturbances ◽  
Age Dependent

Capillary cerebral amyloid angiopathy is associated with vessel occlusion and cerebral blood flow disturbances

2009 ◽  
Vol 30 (12) ◽  
pp. 1936-1948 ◽  
Author(s):  
Dietmar Rudolf Thal ◽  
Estibaliz Capetillo-Zarate ◽  
Sergey Larionov ◽  
Matthias Staufenbiel ◽  
Stefan Zurbruegg ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Cerebral Amyloid Angiopathy ◽  
Amyloid Angiopathy ◽  
Vessel Occlusion ◽  
Flow Disturbances ◽  
Cerebral Amyloid

Effects of profound hypotension on cerebral blood flow during surgery for intracranial aneurysms

1981 ◽  
Vol 55 (6) ◽  
pp. 857-864 ◽  
Author(s):  
J. Keith Farrar ◽  
Francis W. Gamache ◽  
Gary G. Ferguson ◽  
John Barker ◽  
George P. Varkey ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Neurological Status ◽  
Neurological Deficits ◽  
Arterial Spasm ◽  
Arterial Blood ◽  
Flow Disturbances ◽  
Group I ◽  
Increased Risk ◽  
Profound Hypotension

✓ The progression of changes in cerebral blood flow (CBF) and neurological status were measured in 12 patients in whom profound hypotension (mean arterial blood pressure (MABP): 30 to 40 mm Hg) was used during intracranial aneurysm surgery. Nine patients (Group I) showed autoregulation of CBF to an MABP of 40 to 50 mm Hg during surgery. None of these patients had arterial spasm preoperatively. Postoperatively, mild flow disturbances were noted at the site of retraction. Three Group I patients developed arterial spasm postoperatively, but there was no associated neurological deterioration. The remaining three patients (Group II) had impaired autoregulation during surgery, and CBF decreased by 35% to 65% at an MABP of 50 mm Hg. Two of these patients had angiography immediately before surgery, and both showed moderate to severe arterial spasm. Relatively severe flow disturbances were noted postoperatively at the site of retraction, and two patients developed ischemic deficits of late onset. Brain retractor pressure and the degree and duration of hypotension were equivalent in the two patient groups. There was no correlation between intraoperative reductions in CBF (to as low as 20 ml/100 gm/min in the unretracted hemisphere) and immediate postoperative neurological deficits. The use of halothane and mannitol and the relatively short duration of the flow reductions were suggested as factors contributing to the protection from ischemia that was observed. Arterial spasm was found to produce hemodynamic instability and reduced CBF, although neurological status was unaffected in the majority of patients. Patients with impaired autoregulation during surgery were at increased risk of delayed ischemic complications postoperatively, and showed characteristic flow disturbances at all three stages of their clinical course.

scholarly journals A system for assessing the functional state of blood flow in the skin surface layers by the speckle structure of multiply scattered optical radiation

Doklady BGUIR ◽  
2020 ◽  
Vol 18 (8) ◽  
pp. 14-20
Author(s):  
N. D. Abramovich ◽  
S. K. Dick
Keyword(s):  
Blood Flow ◽  
Nervous System ◽  
Functional State ◽  
Optical Radiation ◽  
Skin Surface ◽  
Modern Medicine ◽  
Surface Layers ◽  
Plasma Protein Concentration ◽  
Speckle Structure ◽  
Flow Disturbances

Assessment of the parameters of skin microcirculation is an urgent and important task of modern medicine in the development of methods for diagnosing diseases of the nervous system. The system for assessing the functional state of blood flow in the skin surface layers in the wavelength range from 400 to 850 nm has been improved based on the use of an extended mathematical model of the propagation of optical radiation in human skin by taking into account additional parameters: optical anisotropy of the skin, diameter and shape of erythrocytes in the dermis layer, blood pressure in the brachial artery in the range from 90/60 to 195/130 mm·Hg, plasma protein concentration in the blood (α1, α2, β1, β2, γ-globulins and fibrinogen, g/l), rheological properties of blood flow with a diameter of blood vessels from 4.5 to 500 microns in the skin surface layers, skin temperature from +35 to +41 °C. The developed system makes it possible to determine the severity of microhemodynamic shifts in relation to metabolic disorders, improve diagnosis and evaluate the treatment efficacy of a number of neurological disorders; it also made it possible to reduce the patient examination time and increase the accuracy of measuring the blood flow microcirculation parameters by 10 % (linear and volumetric blood flow velocities) to detect blood flow disturbances in the surface layers of the skin in the normal and abnormal condition of the nervous system.

Multiphoton Microscopy of Healthy and Aneurismal Human Ascending Aorta

2009 ◽  
Author(s):  
Stacey L. Meadley ◽  
Umakanta Tripathy ◽  
Paul W. Wiseman ◽  
Richard L. Leask
Keyword(s):  
Blood Flow ◽  
Aortic Wall ◽  
Surgical Intervention ◽  
Multiphoton Microscopy ◽  
Ascending Aorta ◽  
The Body ◽  
Physiological Conditions ◽  
Flow Disturbances ◽  
Original Size ◽  
Elastic Lamina

The ascending aorta (AA) is the largest artery in the human body. It is responsible for transporting blood between the heart and the rest of the body. The structure of the AA allows it to withstand the resulting blood flow forces. This unique structure is due primarily to the proteins collagen and elastin. Collagen accounts for the strength of the aorta while the mechanical properties of the tissue, under healthy physiological conditions, is dominated by the elastin. Aneurysms are the primary disease associated with the AA, where the diameter of the vessel increases over 1.5 times its original size. Aneurysms can result in severe blood flow disturbances or rupture of the AA and almost always require surgical intervention. The development of an aneurysm is due to a weakening of the aortic wall, specifically the degradation of the structural proteins. This study examines the changes that occur to collagen and elastin in the ascending aorta with aneurysms using multiphoton microscopy. Specifically, the orientation of collagen fibers and the morphology of the fenestrations in the elastic lamina are compared between healthy and dilated human ascending aortas.

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