The Experts below are selected from a list of 30 Experts worldwide ranked by ideXlab platform
Julius M. Gardin - One of the best experts on this subject based on the ideXlab platform.
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Calculation of Volume Flow rate by the proximal isovelocity surface area method: Simplified approach using color Doppler zero baseline shift
Journal of the American College of Cardiology, 1993Co-Authors: Toshinori Utsunomiya, Rajen Doshi, Dharmendra Patel, Walter L. Henry, Kapil Mehta, Dat Nguyen, Julius M. GardinAbstract:Objectives. The goal of this study was to develop an accurate, simplified proximal isovelocity surface area (PISA) method for calculating Volume Flow rate using lower blue-red interface velocity produced by a color Doppler zero baseline shift technique. Background. The Doppler color proximal isovelocity surface area method has been shown to be accurate for calculating the Volume Flow rate (Q) across a narrowed orifice by the formula Q = PISA × Blue-red interface velocity. A hemispheric model is generally used to calculate proximal isovelocity surface area (PISA = 2πa2, where a = the radius corresponding to the blue-red interface velocity). Although a hemispheric model is simple, requiring measurement of one radius, it may underestimate the Actual Volume Flow rate because, in the general case, the shape of a proximal isovelocity surface area is hemielliptic. Although a hemielliptic model is generally more accurate for calculating proximal isovelocity surface area, it is more complex, requiring measurement of two orthogonal radii. Methods. Sixteen in vitro constant Flow model studies were performed using planar circular orifices (diameter range 6 to 16 mm). The blue-red interface velocity was changed from 3 to 54 cm/s using color Doppler zero baseline shift. Results. 1) With decreasing blue-red interface velocity, the size of the proximal isovelocity surface area was increased, and its shape changed from hemielliptic to hemispheric. 2) With the blue-red interface velocity in the range 11 to 15 cm/s, the proximal isovelocity surface area became nearly hemispheric; however, it was difficult to determine the blue-red interface radius at a blue-red interface velocity
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Doppler color Flow mapping of the proximal isovelocity surface area: a new method for measuring Volume Flow rate across a narrowed orifice.
Journal of The American Society of Echocardiography, 1991Co-Authors: Toshinori Utsunomiya, Toshio Ogawa, Hoang A. Tang, Rajen Doshi, Dharmendra Patel, Maureen Quan, Walter L. Henry, Julius M. GardinAbstract:This manuscript describes a new method, validated in in vitro models, for quantitating Volume Flow rate across an orifice with Doppler color Flow mapping. Flow through a narrowed orifice is characterized by the convergence of radial streamlines proximal to the orifice. In this color Doppler method, one or more isovelocity surface areas (PISA), delineated by blue and red aliasing velocity interfaces, can be identified proximal to the narrowed orifice. Volume Flow rate (in milliliters per second) can then be calculated as PISA (in square centimeters) multiplied by the isovelocity of the PISA (in centimeters per second). Doppler color Flow mapping was performed in in vitro models of constant and pulsatile Flow through an orifice in a wall. The first proximal isovelocity surface area, with an isovelocity corresponding to the aliasing velocity, that is, one half the Nyquist sampling limit, could be identified as a blue and red color interface proximal to the orifice. Over a range of circular orifice diameters from 3 mm to 16 mm and Flow rates from 0.5 to 18.7 L/min, the proximal isovelocity surface area could be imaged in two planes. This PISA was best described by a hemielliptic mathematical model with two different radii measured from long-axis and short-axis views. In the constant Flow model, Volume Flow rate calculated from the Doppler PISA correlated well with Actual Volume Flow rate measured simultaneously with a cylinder and stopwatch ( r = 0.98, p r = 0.99, p
Toshinori Utsunomiya - One of the best experts on this subject based on the ideXlab platform.
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Calculation of Volume Flow rate by the proximal isovelocity surface area method: Simplified approach using color Doppler zero baseline shift
Journal of the American College of Cardiology, 1993Co-Authors: Toshinori Utsunomiya, Rajen Doshi, Dharmendra Patel, Walter L. Henry, Kapil Mehta, Dat Nguyen, Julius M. GardinAbstract:Objectives. The goal of this study was to develop an accurate, simplified proximal isovelocity surface area (PISA) method for calculating Volume Flow rate using lower blue-red interface velocity produced by a color Doppler zero baseline shift technique. Background. The Doppler color proximal isovelocity surface area method has been shown to be accurate for calculating the Volume Flow rate (Q) across a narrowed orifice by the formula Q = PISA × Blue-red interface velocity. A hemispheric model is generally used to calculate proximal isovelocity surface area (PISA = 2πa2, where a = the radius corresponding to the blue-red interface velocity). Although a hemispheric model is simple, requiring measurement of one radius, it may underestimate the Actual Volume Flow rate because, in the general case, the shape of a proximal isovelocity surface area is hemielliptic. Although a hemielliptic model is generally more accurate for calculating proximal isovelocity surface area, it is more complex, requiring measurement of two orthogonal radii. Methods. Sixteen in vitro constant Flow model studies were performed using planar circular orifices (diameter range 6 to 16 mm). The blue-red interface velocity was changed from 3 to 54 cm/s using color Doppler zero baseline shift. Results. 1) With decreasing blue-red interface velocity, the size of the proximal isovelocity surface area was increased, and its shape changed from hemielliptic to hemispheric. 2) With the blue-red interface velocity in the range 11 to 15 cm/s, the proximal isovelocity surface area became nearly hemispheric; however, it was difficult to determine the blue-red interface radius at a blue-red interface velocity
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Doppler color Flow mapping of the proximal isovelocity surface area: a new method for measuring Volume Flow rate across a narrowed orifice.
Journal of The American Society of Echocardiography, 1991Co-Authors: Toshinori Utsunomiya, Toshio Ogawa, Hoang A. Tang, Rajen Doshi, Dharmendra Patel, Maureen Quan, Walter L. Henry, Julius M. GardinAbstract:This manuscript describes a new method, validated in in vitro models, for quantitating Volume Flow rate across an orifice with Doppler color Flow mapping. Flow through a narrowed orifice is characterized by the convergence of radial streamlines proximal to the orifice. In this color Doppler method, one or more isovelocity surface areas (PISA), delineated by blue and red aliasing velocity interfaces, can be identified proximal to the narrowed orifice. Volume Flow rate (in milliliters per second) can then be calculated as PISA (in square centimeters) multiplied by the isovelocity of the PISA (in centimeters per second). Doppler color Flow mapping was performed in in vitro models of constant and pulsatile Flow through an orifice in a wall. The first proximal isovelocity surface area, with an isovelocity corresponding to the aliasing velocity, that is, one half the Nyquist sampling limit, could be identified as a blue and red color interface proximal to the orifice. Over a range of circular orifice diameters from 3 mm to 16 mm and Flow rates from 0.5 to 18.7 L/min, the proximal isovelocity surface area could be imaged in two planes. This PISA was best described by a hemielliptic mathematical model with two different radii measured from long-axis and short-axis views. In the constant Flow model, Volume Flow rate calculated from the Doppler PISA correlated well with Actual Volume Flow rate measured simultaneously with a cylinder and stopwatch ( r = 0.98, p r = 0.99, p
Walter L. Henry - One of the best experts on this subject based on the ideXlab platform.
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Calculation of Volume Flow rate by the proximal isovelocity surface area method: Simplified approach using color Doppler zero baseline shift
Journal of the American College of Cardiology, 1993Co-Authors: Toshinori Utsunomiya, Rajen Doshi, Dharmendra Patel, Walter L. Henry, Kapil Mehta, Dat Nguyen, Julius M. GardinAbstract:Objectives. The goal of this study was to develop an accurate, simplified proximal isovelocity surface area (PISA) method for calculating Volume Flow rate using lower blue-red interface velocity produced by a color Doppler zero baseline shift technique. Background. The Doppler color proximal isovelocity surface area method has been shown to be accurate for calculating the Volume Flow rate (Q) across a narrowed orifice by the formula Q = PISA × Blue-red interface velocity. A hemispheric model is generally used to calculate proximal isovelocity surface area (PISA = 2πa2, where a = the radius corresponding to the blue-red interface velocity). Although a hemispheric model is simple, requiring measurement of one radius, it may underestimate the Actual Volume Flow rate because, in the general case, the shape of a proximal isovelocity surface area is hemielliptic. Although a hemielliptic model is generally more accurate for calculating proximal isovelocity surface area, it is more complex, requiring measurement of two orthogonal radii. Methods. Sixteen in vitro constant Flow model studies were performed using planar circular orifices (diameter range 6 to 16 mm). The blue-red interface velocity was changed from 3 to 54 cm/s using color Doppler zero baseline shift. Results. 1) With decreasing blue-red interface velocity, the size of the proximal isovelocity surface area was increased, and its shape changed from hemielliptic to hemispheric. 2) With the blue-red interface velocity in the range 11 to 15 cm/s, the proximal isovelocity surface area became nearly hemispheric; however, it was difficult to determine the blue-red interface radius at a blue-red interface velocity
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Doppler color Flow mapping of the proximal isovelocity surface area: a new method for measuring Volume Flow rate across a narrowed orifice.
Journal of The American Society of Echocardiography, 1991Co-Authors: Toshinori Utsunomiya, Toshio Ogawa, Hoang A. Tang, Rajen Doshi, Dharmendra Patel, Maureen Quan, Walter L. Henry, Julius M. GardinAbstract:This manuscript describes a new method, validated in in vitro models, for quantitating Volume Flow rate across an orifice with Doppler color Flow mapping. Flow through a narrowed orifice is characterized by the convergence of radial streamlines proximal to the orifice. In this color Doppler method, one or more isovelocity surface areas (PISA), delineated by blue and red aliasing velocity interfaces, can be identified proximal to the narrowed orifice. Volume Flow rate (in milliliters per second) can then be calculated as PISA (in square centimeters) multiplied by the isovelocity of the PISA (in centimeters per second). Doppler color Flow mapping was performed in in vitro models of constant and pulsatile Flow through an orifice in a wall. The first proximal isovelocity surface area, with an isovelocity corresponding to the aliasing velocity, that is, one half the Nyquist sampling limit, could be identified as a blue and red color interface proximal to the orifice. Over a range of circular orifice diameters from 3 mm to 16 mm and Flow rates from 0.5 to 18.7 L/min, the proximal isovelocity surface area could be imaged in two planes. This PISA was best described by a hemielliptic mathematical model with two different radii measured from long-axis and short-axis views. In the constant Flow model, Volume Flow rate calculated from the Doppler PISA correlated well with Actual Volume Flow rate measured simultaneously with a cylinder and stopwatch ( r = 0.98, p r = 0.99, p
Rajen Doshi - One of the best experts on this subject based on the ideXlab platform.
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Calculation of Volume Flow rate by the proximal isovelocity surface area method: Simplified approach using color Doppler zero baseline shift
Journal of the American College of Cardiology, 1993Co-Authors: Toshinori Utsunomiya, Rajen Doshi, Dharmendra Patel, Walter L. Henry, Kapil Mehta, Dat Nguyen, Julius M. GardinAbstract:Objectives. The goal of this study was to develop an accurate, simplified proximal isovelocity surface area (PISA) method for calculating Volume Flow rate using lower blue-red interface velocity produced by a color Doppler zero baseline shift technique. Background. The Doppler color proximal isovelocity surface area method has been shown to be accurate for calculating the Volume Flow rate (Q) across a narrowed orifice by the formula Q = PISA × Blue-red interface velocity. A hemispheric model is generally used to calculate proximal isovelocity surface area (PISA = 2πa2, where a = the radius corresponding to the blue-red interface velocity). Although a hemispheric model is simple, requiring measurement of one radius, it may underestimate the Actual Volume Flow rate because, in the general case, the shape of a proximal isovelocity surface area is hemielliptic. Although a hemielliptic model is generally more accurate for calculating proximal isovelocity surface area, it is more complex, requiring measurement of two orthogonal radii. Methods. Sixteen in vitro constant Flow model studies were performed using planar circular orifices (diameter range 6 to 16 mm). The blue-red interface velocity was changed from 3 to 54 cm/s using color Doppler zero baseline shift. Results. 1) With decreasing blue-red interface velocity, the size of the proximal isovelocity surface area was increased, and its shape changed from hemielliptic to hemispheric. 2) With the blue-red interface velocity in the range 11 to 15 cm/s, the proximal isovelocity surface area became nearly hemispheric; however, it was difficult to determine the blue-red interface radius at a blue-red interface velocity
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Doppler color Flow mapping of the proximal isovelocity surface area: a new method for measuring Volume Flow rate across a narrowed orifice.
Journal of The American Society of Echocardiography, 1991Co-Authors: Toshinori Utsunomiya, Toshio Ogawa, Hoang A. Tang, Rajen Doshi, Dharmendra Patel, Maureen Quan, Walter L. Henry, Julius M. GardinAbstract:This manuscript describes a new method, validated in in vitro models, for quantitating Volume Flow rate across an orifice with Doppler color Flow mapping. Flow through a narrowed orifice is characterized by the convergence of radial streamlines proximal to the orifice. In this color Doppler method, one or more isovelocity surface areas (PISA), delineated by blue and red aliasing velocity interfaces, can be identified proximal to the narrowed orifice. Volume Flow rate (in milliliters per second) can then be calculated as PISA (in square centimeters) multiplied by the isovelocity of the PISA (in centimeters per second). Doppler color Flow mapping was performed in in vitro models of constant and pulsatile Flow through an orifice in a wall. The first proximal isovelocity surface area, with an isovelocity corresponding to the aliasing velocity, that is, one half the Nyquist sampling limit, could be identified as a blue and red color interface proximal to the orifice. Over a range of circular orifice diameters from 3 mm to 16 mm and Flow rates from 0.5 to 18.7 L/min, the proximal isovelocity surface area could be imaged in two planes. This PISA was best described by a hemielliptic mathematical model with two different radii measured from long-axis and short-axis views. In the constant Flow model, Volume Flow rate calculated from the Doppler PISA correlated well with Actual Volume Flow rate measured simultaneously with a cylinder and stopwatch ( r = 0.98, p r = 0.99, p
Dharmendra Patel - One of the best experts on this subject based on the ideXlab platform.
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Calculation of Volume Flow rate by the proximal isovelocity surface area method: Simplified approach using color Doppler zero baseline shift
Journal of the American College of Cardiology, 1993Co-Authors: Toshinori Utsunomiya, Rajen Doshi, Dharmendra Patel, Walter L. Henry, Kapil Mehta, Dat Nguyen, Julius M. GardinAbstract:Objectives. The goal of this study was to develop an accurate, simplified proximal isovelocity surface area (PISA) method for calculating Volume Flow rate using lower blue-red interface velocity produced by a color Doppler zero baseline shift technique. Background. The Doppler color proximal isovelocity surface area method has been shown to be accurate for calculating the Volume Flow rate (Q) across a narrowed orifice by the formula Q = PISA × Blue-red interface velocity. A hemispheric model is generally used to calculate proximal isovelocity surface area (PISA = 2πa2, where a = the radius corresponding to the blue-red interface velocity). Although a hemispheric model is simple, requiring measurement of one radius, it may underestimate the Actual Volume Flow rate because, in the general case, the shape of a proximal isovelocity surface area is hemielliptic. Although a hemielliptic model is generally more accurate for calculating proximal isovelocity surface area, it is more complex, requiring measurement of two orthogonal radii. Methods. Sixteen in vitro constant Flow model studies were performed using planar circular orifices (diameter range 6 to 16 mm). The blue-red interface velocity was changed from 3 to 54 cm/s using color Doppler zero baseline shift. Results. 1) With decreasing blue-red interface velocity, the size of the proximal isovelocity surface area was increased, and its shape changed from hemielliptic to hemispheric. 2) With the blue-red interface velocity in the range 11 to 15 cm/s, the proximal isovelocity surface area became nearly hemispheric; however, it was difficult to determine the blue-red interface radius at a blue-red interface velocity
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Doppler color Flow mapping of the proximal isovelocity surface area: a new method for measuring Volume Flow rate across a narrowed orifice.
Journal of The American Society of Echocardiography, 1991Co-Authors: Toshinori Utsunomiya, Toshio Ogawa, Hoang A. Tang, Rajen Doshi, Dharmendra Patel, Maureen Quan, Walter L. Henry, Julius M. GardinAbstract:This manuscript describes a new method, validated in in vitro models, for quantitating Volume Flow rate across an orifice with Doppler color Flow mapping. Flow through a narrowed orifice is characterized by the convergence of radial streamlines proximal to the orifice. In this color Doppler method, one or more isovelocity surface areas (PISA), delineated by blue and red aliasing velocity interfaces, can be identified proximal to the narrowed orifice. Volume Flow rate (in milliliters per second) can then be calculated as PISA (in square centimeters) multiplied by the isovelocity of the PISA (in centimeters per second). Doppler color Flow mapping was performed in in vitro models of constant and pulsatile Flow through an orifice in a wall. The first proximal isovelocity surface area, with an isovelocity corresponding to the aliasing velocity, that is, one half the Nyquist sampling limit, could be identified as a blue and red color interface proximal to the orifice. Over a range of circular orifice diameters from 3 mm to 16 mm and Flow rates from 0.5 to 18.7 L/min, the proximal isovelocity surface area could be imaged in two planes. This PISA was best described by a hemielliptic mathematical model with two different radii measured from long-axis and short-axis views. In the constant Flow model, Volume Flow rate calculated from the Doppler PISA correlated well with Actual Volume Flow rate measured simultaneously with a cylinder and stopwatch ( r = 0.98, p r = 0.99, p
