Quantification of flow volume with a new digital three‐dimensional color Doppler flow approach: an in vitro study.

Abstract

Objective. The quantification of flow stroke volume is important for evaluation of patients with cardiac dysfunction and cardiovascular disease. Three-dimensional digital color Doppler flow imaging allows the acquisition of flow data in an orientation approximately parallel to flow and analysis of the Doppler flow velocities perpendicular to flow (cross-sectional flow calculation). This in vitro study assessed the applicability of this method for quantifying cardiac output in a funnel-shaped tube model similar to mitral inflow or the left ventricular outflow tract. Methods. A new digital three-dimensional color Doppler method was used to acquire Doppler flow information. Raw scan line data with digital velocity assignments were obtained on a conventional Doppler color flow imaging system with a 180°rotating multiplanar transesophageal probe connected to a computer workstation. Nine stroke volumes (20-60 mL) with flow rates ranging from 1.5 to 5.28 L/min in a funnel-shaped pulsatile laminar flow model were studied. Three-dimensional flow rates were compared with standard-of-reference measurements of flow obtained from timed collection in a graduated cylinder and with an ultrasonic flow meter. Results. Within the funnel tube, the flow volumes that were calculated from the first, second, and third depths and the average of all 3 depths correlated well with the actual flow rate (r = 0.97-0.99). Results from the middle and second levels and from the average of all 3 depths provided the closest fit to the actual flow rates (r = 0.99; y = 0.96x + 0.14; and r = 0.98; y = 1.14x -0.43, respectively). Conclusions. Although a work in progress, this digital three-dimensional color Doppler flow measurement method is feasible, accurate, and simple, and it may offer in vivo evaluation of blood volume flow given a favorable orientation between the valve orifice and the scanning device. Key words: three-dimensional echocardiography; digital color Doppler imaging; flow; angle independence. Abbreviations ACM, automated cardiac output measurement; MRI, magnetic resonance imaging; SEE, standard error of the estimate; TEE, transesophageal echo; 3D, three-dimensional; 2D, two-dimensional ccurate, noninvasive measurement of blood flow in the inflow and outflow tracts of the heart and great arteries continues to be an important clinical goal in the assessment of cardiac function, shunt flows in congenital cardiac defects, and regurgitation in the presence of valvular disease. [1][2][3][4][5][6][7][8][9][10][11][12] Noninvasive methods for the quantification of blood flow include magnetic resonance imaging (MRI) and combinations of M-mode and two-dimensional (2D) echocardiography and spectral Doppler flow. 13 Phase-encoded MRI velocity methods have been used for quantifying flow across

Quantification of the area and shunt volume of multiple, circular, and noncircular ventricular septal defects: A 2D/3D echocardiography comparison and real time 3D color Doppler feasibility determination study

“…Determining VSD shunt volume noninvasively can be accomplished using radionuclide scintigraphy, magnetic resonance imaging (MRI), and 2D color Doppler echocardiography (2D‐CDE) . The accuracy of 2D‐CDE is limited by Doppler angle dependency, 2D geometrical assumptions, and high inter‐observer variability .…”

“…The accuracy of 2D‐CDE is limited by Doppler angle dependency, 2D geometrical assumptions, and high inter‐observer variability . 3D color Doppler echocardiography (3D‐CDE) is without these limitations but is limited by the need for electrocardiogram (ECG) gating, which can allow for artifacts caused by arrhythmias, respiration, and movement …”

“…Determining VSD shunt volume noninvasively can be accomplished using radionuclide scintigraphy, magnetic resonance imaging (MRI), and 2D color Doppler echocardiography (2D-CDE). [12][13][14][15][16][17][18][19][20][21] The accuracy of 2D-CDE is limited by Doppler angle dependency, 2D geometrical assumptions, and high inter-observer variability. 12,14,15 3D color Doppler echocardiography (3D-CDE) is without these limitations but is limited by the need for electrocardiogram (ECG) gating, which can allow for artifacts caused by arrhythmias, respiration, and movement.…”

“…12,14,15 3D color Doppler echocardiography (3D-CDE) is without these limitations but is limited by the need for electrocardiogram (ECG) gating, which can allow for artifacts caused by arrhythmias, respiration, and movement. 8,[21][22][23][24][25][26][27] Instantaneous acquisition of color Doppler volume without gating is made possible by the use of real time 3D-CDE (RT3D-CDE), which uses a matrix phased array transducer acquiring flow information more directly and rapidly than 3D-CDE. 28 Using nongated echocardiography, artifacts caused by gating do not occur.…”

Evaluation of a New 3‐Dimensional Color Doppler Flow Method to Quantify Flow Across the Mitral Valve and in the Left Ventricular Outflow Tract

“…Current 3D Doppler‐based methods require the operator to trace the area of color flow and use electrocardiographically gated 3D echo over an acquisition of more than 7 complete cardiac cycles. Furthermore, as arrhythmias and respiratory movement generate a stitching artifact, it is necessary to optimize acquisition via sinus rhythm gating and breath holding 4 , 5 , 7 , 10 , 11 , 14 , 16 , 17 . It also requires time‐intensive postprocessing to analyze the data and obtain results.…”