Color Doppler Method Research Articles

Finger flexor rigidity in the healthy population

The involvement of the hand flexors in trigger finger is not clear. This study aimed to examine the rigidity of the flexor tendon in the first pulley territory in the hand by using ultrasound in a healthy population, as well as to create a reference scale of rigidity for the flexor tendons to compare those values in trigger fingers. We tested 35 healthy volunteers using a linear ultrasound transducer and the color Doppler method. Rigidity levels below the first pulley were examined and compared between the different fingers of the hand and the relationship between rigidity and sex and the three different age groups was evaluated. In the healthy population, the rigidity of the flexor tendons of the hand in the territory of the first pulley varied between 233.1 and 962.8 kPa, with an average of 486.42 kPa and standard deviation of 114.85. We showed that the flexors in the dominant hand were more rigid, there was a difference between the rigidity of the flexor tendons of the thumb and the other fingers of the same hand, and the ring finger of the dominant hand had stiffer flexor tendons than the fingers of the other hand in the male population. We created a value scale for the rigidity of the flexor tendons of the fingers. This base scale can be compared between different pathologies, including trigger finger. The study and all experimental protocols were approved by the local ethical committee.

Transabdominal Ultrasonography for Preoperative Diagnosis of Lymph Node Metastasis in Colon Cancer: A Retrospective Cohort Study.

Although computed tomography (CT) is the standard modality for diagnosing lymph node metastasis (LNM), transabdominal ultrasonography (US) can be useful due to its high spatial resolution and use of Doppler signals to precisely analyse lymph nodes. This study aimed to evaluate the accuracy of US for lymph node assessment, establish US-based diagnostic criteria for LNM, and compare the capability of US with that of CT for the diagnosis of LNM. This retrospective, single-institution, cohort study included patients who underwent radical surgery for clinical stage 0-III colon cancer, between March 2012 and February 2019. Overall, 34.9% (66/189) of patients had pathological LNM. The optimal US diagnostic criteria were 1) short axis ≥7 mm and short/long ratio ≥0.75 and 2) at least two of the following: the absence of hilar echoes, expansive appearance, or peripheral/mixed vascularity by the colour Doppler and/or contrast-enhanced method. Compared to CT, US showed a higher diagnostic sensitivity (54.5% vs. 43.9%; p=0.296), higher concordance with the number of pathological LNM (correlation coefficient: US, 0.42; CT, 0.27) and pathological N diagnosis (weighted ĸ: US, 0.35; CT, 0.18), and higher sensitivity for advanced LNM, including multiple LNMs (47.4% vs. 18.4%; p=0.014) and N2 stage (27.8% vs. 5.6%; p=0.177). US has higher sensitivity than CT for diagnosing LNM in colon cancer, along with a more accurate preoperative diagnosis of the N stage. Additionally, US may be more helpful than CT alone for preoperatively deciding the appropriateness of neoadjuvant treatment in colon cancer with advanced LNM.

Identification of Speckle Structures for the Needs of Mapping of Biological Fluids

A color Doppler mapping method for ophthalmic applications of optical coherence tomography (OCT) is presented. The proposed method was developed taking into account the regularities that link changes in the interference signal with the changes in the characteristics of the flow of biological fluid through the OCT scanning plane that cause them. The key feature of the proposed algorithm is the multistage analysis of fluctuations in the speckle structure of OCT images. Speckle structures are identified by using the functions of color reversal, convolution using a given convolution kernel, threshold constraints, morphological processing, convex hull formation, gradient operations, and image recoding.

Blood flow image by multi-angle composite ultrasonic Doppler vector

Precise measurement of blood flow is of vital importance in studying the formation of thrombus and atherosclerotic plaque. However, conventional color Doppler methods are limited to obtaining the velocity component along the ultrasound beam and have poor accuracy. Several Doppler flow imaging methods based on the plane wave emission can estimate the blood velocity vectors and visualize hemodynamic parameters, which provide more detailed blood flow information and effectively improve the capability of clinical diagnosis treatment. Considering the low accuracy of the Doppler flow methods for measuring velocity in complex flow fields, an optimization technique is used to improve the imaging quality and the accuracy of velocity estimation. In this study we propose a modified vector Doppler method through combining multi-angle compound technique, to reconstruct blood velocity vectors of carotid bifurcations obtained from 3D printing. Since the multi-angle compound technology can effectively improve the quality of imaging, this technology is applied to Doppler imaging to achieve high-accuracy velocity estimation. It can significantly reduce the velocity estimation errors. Comparing the velocity estimation accuracy of different angle compound numbers (<i>n</i> = 1, 3, 5, and 7) in the simulation, it is found that the accuracy of velocity estimation increases with angle compound increasing. Beside, the 5-angle compound method is more robust for velocity estimation and can obtain higher frames. The experiments were carried out using a programmable ultrasonic array system and a high-frequency linear array transducer L12-5c with a central frequency of 8.125 MHz. The sample rate is set to be 31.25 MHz. The imaging results of carotid bifurcation also show that the vector Doppler based on 5-angle compound can obtain a clear image of intravascular vector flow, which is beneficial to the identifying of complex flow state, and realize intravascular dynamic imaging. Especially, it can capture the vortex phenomenon in the blood stream. The quantitative results indicate that this method significantly reduces the error between the flow calculation results and the reference results, making the estimation results more accurate. In conclusion, the vector Doppler method based on multi-angle compound has the good performance of visualizing complex blood flow and calculating hemodynamic parameters. It also provides the reference for the diagnosis of cardiovascular disease and the research of flow imaging methods.

Binary Pattern Color Doppler Shear Wave Elastography.

Some studies suggested a correlation between tissue elasticity and diseases, such as Adhesive Capsulitis (AC) of the shoulder. One category of method to measure elasticity is by utilizing Doppler imaging. This paper discusses color Doppler shear wave elastography methods and demonstrated an experiment with biological tissue mimicking phantom. A simulation with binary pattern color Doppler shear wave elastography shows that wavelength of a shear wave with suggested magnitude is equal to four multiple of pitch strip in a color flow image. However, the larger amplitude changes the duty ratio and frequency of the pattern. An experiment with biological tissue mimicking Polyvinyl Alcohol (PVA) phantoms has shown that the binary pattern color Doppler method has successfully recovered shear wave velocity map and calculate the elasticity.Clinical Relevance-The result of experiments presents a possibility of using the method for quantitatively access the stage of tissue stiffness related disease.

Suppression of reflected signals from substrate as clutters for cell measurements using acoustic impedance microscopy

Recently, a method for estimating three-dimensional acoustic impedance profiles in cultured cells and human dermal organs was proposed by interpreting the reflected ultrasonic signal based on a 1-D transmission line model for acoustic impedance microscopy (AIM). However, AIM has a disadvantage that reflected signals from cells overlap with that from a reference substrate. Additionally, the amplitudes of the reflected signals from the specimens are significantly weaker than that from the substrate. In this paper, we proposed a new method for separation of those signals based on a concept of clutter filter, which had been developed for a color Doppler method in medical ultrasonic imaging. The proposed filter using singular value decomposition (SVD) could separate original signals into desired signals such as those from the substrate and cells. Additionally, an effect from a tilt of the substrate was investigated in this study. Separability of the proposed filter was evaluated by two investigations. First one was to evaluate the separability by estimating a correlation coefficient between the filtered signal and signal reflected from a position only with the substrate. Second one was to compare a slope of the substrate estimated from the original signal with that estimated from the filtered signals from the substrate. The experimental results showed that the proposed filter could separate signals from the substrate, and the compensation of the tilt of the substrate could improve the performance of the proposed filter.

Emerging Technology: Ultrasound Vector Flow Imaging—A Novel Approach to Arterial Hemodynamic Quantification

Accurate, reliable, and easily obtainable quantification of peripheral arterial hemodynamic states has long been a holy grail of vascular ultrasound. While conventional Doppler modalities have been relied upon for decades to provide velocity, directionality, and flow volume data for integration into patient management schema, they carry limitations in accurately and reproducibly quantifying complex arterial hemodynamic patterns. Advances in ultrasound imaging architecture, such as virtual beamforming, integration of “big data” capabilities, and the use of enhanced digital signal processing methods have opened the door for a novel approach to arterial hemodynamic mapping and quantification—ultrasound vector flow imaging (VFI). This article presents an overview of the technological underpinnings of VFI, compares it with conventional pulsed wave and color Doppler methods, and describes the potential clinical benefits of this emerging vascular ultrasound modality.

Alterations of Uterine Blood Flow During the Follicular Phase in Patients With Recurrent Implantation Failure: A Doppler Ultrasonographic Study

Objectives: The dynamics of blood flow in the endometrium plays a crucial role during the implantation process. This study aimed to assess the uterine perfusion during the follicular phase in patients with a history of recurrent implantation failure (RIF) and healthy fertile women using the transvaginal ultrasound color Doppler method. Materials and Methods: To this end, 50 patients with RIF and 50 age-matched healthy fertile women were recruited in this case-control study. The transvaginal color Doppler ultrasonography was used to evaluate the pulsatility index (PI) and resistance index (RI) of the uterine, arcuate, and sub-endometrial arteries during the follicular phase in both groups. Results: The RI and PI of both right and left uterine arteries were higher in the RIF group compared to the fertile women (P<0.05). Our results showed that the PI and RI of sub-endometrial blood flow and the RI of arcuate arteries were substantially higher in the group with a history of RIF in comparison with the control group. However, the PI of arcuate arteries was not significantly different between the groups. Conclusions: Adequate uterine perfusion and sub-endometrial blood flow are necessary to achieve successful implantation and pregnancy since our results demonstrated the higher resistance of uterine and sub-endometrial arteries in patients with a history of RIF. Thus, the assessments of uterine perfusion indices during the follicular phase could be used as a non-invasive method in the evaluation of patients with RIF.

Diagnostic and Prognostic Value of Several Color Doppler Jet Grading Methods in Patients With Mitral Regurgitation

Color Doppler is a widely used ultrasound imaging method for assessing mitral regurgitation (MR) in clinical practice. Nevertheless, color Doppler-based grading of the MR jet has been rarely considered in clinical studies. We investigated the diagnostic and prognostic value of several color Doppler MR jet grading methods and compared them with quantitative grading of MR. The MR color Doppler jet was assessed in 476 MR patients using an 'integrated' eyeballing approach by quantifying the color Doppler jet area, jet area/left atrium area and jet length and using quantitative methods. Clinical endpoints were scored as major adverse clinical events, including cardiovascular death, heart failure hospitalization and mitral valve intervention. When assessed by three echocardiographers, there was a moderate inter-observer agreement for eyeballing color Doppler grade of MR (intraclass correlation coefficient 0.69, p < 0.001). The intra-observer agreement was good for all color Doppler approaches. In primary MR, eyeballing color Doppler correlated well with (in)direct measures of MR severity, with a negative predictive value of 91% when using a grade 2 color Doppler as cut-off. In secondary MR, eyeballing color Doppler grade and jet length were predictors of clinical outcome in Cox proportional hazards analysis (p = 0.003), independent of pulmonary pressures, atrial and ventricular volumes. Overall, the integrated eyeballing approach performed better than color Doppler quantification of the MR jet area and length. In conclusion, this study shows that color Doppler grading of the distal MR jet performs well in predicting events in primary and secondary MR, compared to quantitative grading methods.

The diagnostic value of non-invasive serum liver fibrosis indices in the prediction of portal hypertension in cirrhotic patients: a cross-sectional study

Introduction: Considering that portal hypertension is principally caused by hepatic fibrosis, some studies postulated the predictive value of serum liver fibrosis indices in the diagnosis of portal hypertension. In this study we assessed the prognostic value of serum indices in the diagnosis of portal hypertension in cirrhotic patients. Methods: One hundred two cirrhotic patients were selected according to inclusion/exclusion criteria. Cirrhosis and the Child-Pugh score was determined by the gastroenterologist. Portal hypertension was diagnosed by the radiologist using the color Doppler method. The fasting blood sample was drawn and different serum indices were determined. The following indices were calculated: FIB4, Fibroindex, APRI, FORNS, LOK. Results: The patients mean age was 54.39±6.60 years. About 52.94% of the patients were women. The mean liver enzymes level was higher in patients with portal hypertension. In 50.98% of patients, the etiology of cirrhosis was viral hepatitis. Significant differences was observed between the two groups regarding the studied indices (P&lt;0.05). According to the results of the ROC curve, the FORNS index was a better predictive marker of portal hypertension in cirrhotic patients. The maximum AUC (area under the curve) was for the FORNS index. According to the results of diagnostic tests, the FORNS index had adequate sensitivity and specificity in the diagnosis of portal hypertension with the cut-off value of 8.51. Conclusion: The results of the present study showed that the FORNS index is a better predictor of portal hypertension in cirrhotic patients.

P1554 Assessment of functional mitral regurgitation with leg lift and exercise echocardiography using the average pixel intensity method

Abstract Background Dynamic changes in functional mitral regurgitation (FMR) during exercise echocardiography were shown to be of prognostic value. However grading of FMR is challenging, especially during exercise echocardiography and therefore questioning its applicability in clinical practice. We recently introduced and validated the Average Pixel Intensity (API) for grading MR based on the pixel intensity of the continuous wave Doppler signal. In the current study we investigate the use of the API method using leg lift and exercise echocardiography in FMR. Methods We prospectively included 50 heart failure patients (mean ejection fraction 36%) in sinus rhythm with different grades of pure, FMR. After assessment of FMR severity at rest, the same acquisitions were repeated during leg lift and exercise echocardiography. FMR was assessed using the API method, color Doppler and quantitative grading methods (proximal isovelocity surface area (PISA) and vena contracta width (VCW)). Results The API method could be performed in all patients (100%) with leg lift (n = 50) and in 94% of the patients undergoing exercise echocardiography (n = 44), which was more than PISA and VCW (p &amp;lt; 0.001). During leg lift, there was a small but significant increase on visual color Doppler grading (grade 1.93 to 2.11 (p = 0.004); increase of FMR in 35% of patients, and no difference in 65%). For API, we found the same significant increase (93 to 101 au), however, API values showed increase of MR in 62% and decrease of FMR in 20%. During exercise echocardiography, we found no differences in color Doppler grade and API in the overall cohort (p 0.252 and p 0.832, respectively), despite 62% of patients showing some degree of increase in API during leg lift. On multivariate analysis, no specific echo parameter could be identified as independent predictor of API increase. Conclusions The novel API method is highly feasible for assessing dynamic FMR and may be of added value for in this setting, allowing the detection of even small increments of FMR severity. In the current study, we found only mild increases of FMR during exercise echocardiography. Leg lift testing however proved to be a simple and quick loading approach that induced a significant rise in FMR compared to exercise echocardiography. The prognostic relevance of the findings during leg lift remains to be determined.

Vascular Evaluation around the Cervical Nerve Roots during Ultrasound-Guided Cervical Nerve Root Block.

Introduction To carry out ultrasound-guided cervical nerve root block (CNRB) safely, we investigated the frequency of risky blood vessels around the target nerve root and within the imaginary needle pathway in the actual injecting position. Methods 30 patients (20 men, 10 women) with cervical radiculopathy who received ultrasound-guided CNRB were included in this study. We defined a risky blood vessel as an artery existing within 4 mm from the center of the target nerve root or located in the range of 2 mm above or below the imaginary needle pathway. Results Using the color Doppler method, the frequency of a risky blood vessel existing around 4 mm from the center of the C5 nerve root was 3.3% (1/30), whereas it was 3.3% (1/30) for the C6 nerve root and 23.3% (7/30) for the C7 nerve root. Hence, the C7 level had more blood vessels close to the target nerve root compared to the C5 and C6 levels, but there was no significant difference (p = 0.0523). On the other hand, the frequency of a risky blood vessel existing within 2 mm above and below the imaginary needle pathway was 3.3% (1/30) for the C5 nerve root, whereas it was 3.3% (1/30) for the C6 nerve root and 10.0% (3/30) for the C7 nerve root. The C7 level had more blood vessels within the needle pathway compared to the C5 and C6 levels, but there was no significant difference (p = 0.301). Conclusions To reduce the risk of unintended intravascular injections, more careful checking for the presence or absence of blood vessels at the C7 level using color Doppler is necessary.

Multicenter Prospective Study of Color Doppler Ultrasound for Breast Masses: Utility of Our Color Doppler Method

The use of color Doppler ultrasound (CD) for distinguishing between benign and malignant breast lesions remains controversial. This study (JABTS BC-04 study) was aimed at confirming the usefulness of our CD diagnostic criteria. We evaluated ultrasound images of 1408 solid breast masses from 16 institutions in Japan (malignant: 839, benign: 569). Multivariate analysis indicated that vascularity (amount of blood flow), vascular flow pattern (“surrounding marginal flow” or “penetrating flow”) and the incident angle of penetrating flow were significant findings for distinguishing between benign and malignant lesions. However, the sensitivity and specificity of B-mode alone did not improve significantly with CD addition (97.6% → 97.9%, 38.3% → 41.5%, respectively). We explored the causes of these negative results and found that age should have been considered when evaluating vascularity. Simulation experiments suggested that specificity is significantly improved when age is taken into consideration (38.3% → 46.0%, p < 0.001) and we thereby improved our diagnostic criteria.

Deduction of two-dimensional blood flow vector by dual angle diverging waves from a cardiac sector probe

Color Doppler method is widely used for noninvasive diagnosis of heart diseases. However, the method can measure one-dimensional (1D) blood flow velocity only along an ultrasonic beam. In this study, diverging waves with two different angles were irradiated from a cardiac sector probe to estimate a two-dimensional (2D) blood flow vector from each velocity measured with the angles. The feasibility of the proposed method was evaluated in experiments using flow poly(vinyl alcohol) (PVA) gel phantoms. The 2D velocity vectors obtained with the proposed method were compared with the flow vectors obtained with the particle image velocimetry (PIV) method. Root mean square errors of the axial and lateral components were 11.3 and 29.5 mm/s, respectively. The proposed method was also applied to echo data from the left ventricle of the heart. The inflow from the mitral valve in diastole and the ejection flow concentrating in the aorta in systole were visualized.

Quantitative Analysis of Helical Flow with Accuracy Using Ultrasound Speckle Image Velocimetry: In Vitro and in Vivo Feasibility Studies

Venous valve dysfunction and induced secondary abnormal flows are closely associated with venous diseases. Thus, detailed analysis of venous valvular flow is invaluable from biological and medical perspectives. However, most of the previous studies on venous perivalvular flows were based on qualitative analysis. On the contrary, quantitative analysis of perivalvular flows has not been fully understood. In this study, we used the ultrasound speckle image velocimetry (SIV) technique, which utilizes the speckle patterns of red blood cells (RBCs) created by ultrasound waves to measure 3-D valvular flows quantitatively. The flow structures obtained with the proposed SIV technique for an in vitro model were compared with those obtained by numerical simulation and the color Doppler method to validate the measurement accuracy of the ultrasound SIV technique. Blood flow in the human great saphenous vein was then measured at various distances from the valve with and without exercise. 3-D valvular flow was analyzed in accordance with the dimensionless index, helical intensity. The results obtained by the proposed method matched well with those obtained by numerical simulation and the color Doppler method. The hemodynamic characteristics of 3-D valvular helical flow which were analyzed experimentally using the SIV method would be used for quantitative diagnosis of venous valvular diseases.

Color Doppler for retinopathy of prematurity

The data about use of color Doppler method to study the characteristics of eye blood flow in the preterm infants with retinopathy of prematurity (ROP) are presented in the review. The greatest attention is paid to arterial blood flow examination, and there are only single studies about venous blood flow in ROP. The results presented in different sources indicate on color Doppler informativity in the diagnostics of ROP, however, they are ambiguous and contradictory. It points to the necessity for the further studies on generalization and systematization of the eye blood flow characteristics in the disease, and also on recognition of the most useful indicators for assessing the severity of the pathological process, predicting its course and determining of the optimal management and treatment tactics for patients with ROP.

Real-time 3D echocardiography for estimation of severity in valvular heart disease : Impact on current guidelines

Besides providing spatial anatomic information on heart valves, real-time three-dimensional echocardiography (3DE) combined with color Doppler has the potential to overcome the limitations of flow quantification inherent to conventional 2D color Doppler methods. Recent studies validated the application of color Doppler 3DE (cD-3DE) for the quantification of regurgitation flow based on the vena contracta area (VCA) and the proximal isovelocity surface area (PISA) methods. Particularly the assessment of VCA by cD-3DE led to achange of paradigm by understanding of the VCA as being strongly asymmetric in the majority of patients and etiologies. This review provides acomprehensive description of the different concepts of cD-3DE-based flow quantification in the setting of different valvular heart diseases and their presentation in recent guidelines.

A novel visualization method of bubble cavitation caused by infinitesimal amount of microbubbles

Microbubbles modified with targeting ligands have a potential in early diagnosis by ultrasound because the targeted-bubble has both a selective property for accumulation in diseased area and a high degree of echogenicity. However, conventional ultrasonic imaging methods, such as B-mode and ultrasound color Doppler method, do not have enough sensitivity for microbubbles when only very small amount of microbubbles exists in ROI. In order to detect infinitesimal amount of microbubbles, we proposed a novel visualization of bubble cavitation signal (BCS) induced by high intensity US irradiation. In this method, high intensity US (h-US) is irradiated to microbubble with a fixed time delay after introducing an imaging US (i-US) and BCS is detected by power Doppler imaging unit. Due to the time delay of two waves, BCS appears on power Doppler image as a vertical line image (T-image) whose intensity is modulated by the amplitude of BCS. By this method, BCS measurement which is free both for direct propagated h-US and Doppler signal caused by bubble motion can be achieved. We detected the infinitesimal amount of bubbles (Sonazoid) with the concentration of 8×10-8 μL/ml, which is 100 times lower than minimum detectable sensitivity of B-mode observation.

Three-Dimensional Field Optimization Method: Clinical Validation of a Novel Color Doppler Method for Quantifying Mitral Regurgitation

Assessment of mitral regurgitation (MR) severity by echocardiography is important for clinical decision making, but MR severity can be challenging to quantitate accurately and reproducibly. The accuracy of effective regurgitant orifice area (EROA) and regurgitant volume (RVol) calculated using two-dimensional (2D) proximal isovelocity surface area is limited by the geometric assumptions of proximal isovelocity surface area shape, and both variables demonstrate interobserver variability. The aim of this study was to compare a novel automated three-dimensional (3D) echocardiographic method for calculating MR regurgitant flow using standard 2D techniques. A sheep model of ischemic MR and patients with MR were prospectively examined. Patients with a range of severity of MR were examined. EROA and RVol were calculated from 3D color Doppler acquisitions using a novel computer-automated algorithm based on the field optimization method to measure EROA and RVol. For an independent comparison group, the 3D field optimization method was compared with 2D methods for grading MR in an experimental ovine model of MR. Fifteen 3D data sets from nine sheep (open-chest transthoracic echocardiographic data sets) and 33 transesophageal data sets from patients with MR were prospectively examined. For sheep data sets, mean 2D EROA was 0.16±0.05cm2, and mean 2D RVol was 21.84±8.03mL. Mean 3D EROA was 0.09±0.04cm2, and mean 3D RVol was 14.40±5.79cm3. There was good correlation between 2D and 3D EROA (R=0.70) and RVol (R=0.80). For patient data sets, mean 2D EROA was 0.35±0.35cm2, and mean 2D RVol was 58.9±52.9mL. Mean 3D EROA was 0.34±0.29cm2, and mean 3D RVol was 54.6±36.5mL. There was excellent correlation between 2D and 3D EROA (R=0.94) and RVol (R=0.84). Bland-Altman analysis revealed greater interobserver variability for 2D RVol measurements compared with 3D RVol using the 3D field optimization method measurements, but variability was statistically significant only for RVol. Direct automated measurement of proximal isovelocity surface area region for EROA calculation using real-time 3D color Doppler echocardiography is feasible, with a high correlation to current 2D EROA methods but less variability. This novel automated method provides an accurate and highly reproducible method for calculating EROA.

Three-Dimensional Field Optimization Method: Gold-Standard Validation of a Novel Color Doppler Method for Quantifying Mitral Regurgitation

Accurate diagnosis of mitral regurgitation (MR) severity is central to proper treatment. Although numerous approaches exist, an accurate, gold-standard clinical technique remains elusive. The authors previously reported on the initial development and demonstration of the automated three-dimensional (3D) field optimization method (FOM) algorithm, which exploits 3D color Doppler ultrasound imaging and builds on existing MR quantification techniques. The aim of the present study was to extensively validate 3D FOM in terms of accuracy, ease of use, and repeatability. Three-dimensional FOM was applied to five explanted ovine mitral valves in a left heart simulator, which were systematically perturbed to yield a total of 29 unique regurgitant geometries. Three-dimensional FOM was compared with a gold-standard flow probe, as well as the most clinically prevalent MR volume quantification technique, the two-dimensional (2D) proximal isovelocity surface area (PISA) method. Overall, 3D FOM overestimated and 2D PISA underestimated MR volume, but 3D FOM error had smaller magnitude (5.2±9.9mL) than 2D PISA error (-6.9±7.7mL). Two-dimensional PISA remained superior in diagnosis for round orifices and especially mild MR, as predicted by ultrasound physics theory. For slit-type orifices and severe MR, 3D FOM showed significant improvement over 2D PISA. Three-dimensional FOM processing was technically simpler and significantly faster than 2D PISA and required fewer ultrasound acquisitions. Three-dimensional FOM did not show significant interuser variability, whereas 2D PISA did. Three-dimensional FOM may provide increased clinical value compared with 2D PISA because of increased accuracy in the case of complex or severe regurgitant orifices as well as its greater repeatability and simpler work flow.