3D Color Doppler Imaging Research Articles

Three-dimensional ultrafast ultrasound imaging of blood flow using row-column addressing array: A simulation study

Three-dimensional (3D) ultrafast imaging is important for ultrasound technology development. The traditional 3D imaging method based on fully sampled two-dimensional (2D) matrix often requires a large number of electronic channels with high density which limits the aperture size and imaging resolution in application. Recently developed row-column addressing (RCA) matrix effectively reduces the number of electronic channels from <i>N</i> × <i>N</i> to <i>N</i> + <i>N</i> by addressing the row and column elements. The beamforming strategy designed for 3D ultrasound imaging was based on the coherent compounding of orthogonal plane waves (OPW). Such a multi-angle OPW compounding strategy achieves virtual transmit focusing in both directions by transmitting a set of plane waves in one direction and receiving along the orthogonal direction, which finally leads to an isotropic point spread function (PSF). In this paper, multi-angle OPW method was investigated for 3D blood flow imaging using an RCA matrix with 128 rows and 128 columns, centered at 6 MHz. The delay and sum (DAS) beamforming was developed for coherent OPW compounding, and the singular value decomposition (SVD) filtering method was used for separating the dynamic blood flow signals from the static tissue signals and low-amplitude noise. The Doppler velocity was computed by the autocorrelation method, and finally the 3D power Doppler and color Doppler imaging of the blood flow were realized. To evaluate the imaging quality and investigate the effect of different OPW tilting angles, quantitative analysis was carried out using multiple parameters, including –6 dB resolution measurements of the PSF, SNR of the power Doppler images and velocity distribution of the color Doppler. The –6 dB resolution is improved from 0.986 mm to 0.493 mm with the number of angles increasing from 5 to 33. With 17 plane wave angles, the SNR of the power Doppler image reaches 30 dB, and the average deviation between the velocity distribution along the diameter of the blood flow phantom and the actual value is about 26.0%. In conclusion, results show that the ultrafast 3D imaging method based on RCA matrix can obtain 3D B-mode, power Doppler and color Doppler images. Increasing the number of tilting angles and enlarging the angle range can significantly improve the imaging quality. The proposed method can be helpful for developing 3D ultrafast ultrasound Doppler imaging and functional ultrasound imaging based on neuro-vascular coupling.

Abstract 13922: Association Between Quadrileaflet Tricuspid Valve and Location of Regurgitation Jet Origin in Patients With Functional Severe Tricuspid Regurgitation

Introduction: It has been known that the posterior leaflet of the tricuspid valve (PTL) has several indentations or clefts in its free edge, giving the tricuspid valve (TV) equal to or more than four leaflets appearance. However, little is known about whether the indentations or clefts can be a location of tricuspid regurgitation (TR) jet origin in severe TR. Hypothesis: This study aimed to investigate the association between quadrileaflet TV and location of TR jet origin in patients with functional severe TR. Methods: We retrospectively studied 85 functional severe TR patients who underwent 3D transesophageal echocardiography which was performed using the EPIQ7 ultrasound system with a X8-2t probe (Philips Medical Systems). The morphology of the TV leaflets was ascertained using 3D volume-rendered images. Clefts extending over 50% of the depth of the leaflets were determined as a landmark between 2 adjacent leaflets. The location of TR jet origin and vena contracta area (VCA) were ascertained using real-time 3D color Doppler images. All images were analyzed by using QLAB 3D quantification software (Philips Medical Systems). Results: In 85 functional severe TR patients, a total of 3 (4%) patients with bileaflet, 60 (71%) patients with trileaflet and 22 (26%) patients with quadrileaflet were identified. All quadrileaflet TV had dichotomous PTLs (PTL 1 and PTL 2) and there was no patient who had equal to or more than five leaflets. In 22 patients with quadrileaflet, 10 (45%) patients showed TR jet origin located between PTL 1 and PTL 2 (Figure A). Also, quadrileaflet TV patients with TR jet origin located between PTL 1 and PTL 2 had significantly larger VCA than those without (185 vs. 62 mm2, P<0.001, Figure B). Conclusions: In patients with functional severe TR, one fourth patients showed quadrileaflet TV morphology. Furthermore, TR jet origin located between PTL 1 and PTL 2 can be seen only in a condition of TR beyond severe.

Severe tortuous intra-abdominal segment of isolated single umbilical artery by three-dimensional high-definition flow imaging

The authors report a tortuous intra-abdominal segment of isolated single umbilical artery (SUA) that proved to be an omega-shaped variant by three-dimensional high-definition-flow (3D-HD-flow) imaging. A 28-year-old woman was referred to the present center for detailed fetal echocardiography examination after finding SUA during routine two-dimensional ultrasound examination at 24+3 weeks’ gestation. 3D-HD-flow demonstrated a severely tortuous and dilated intra-abdominal segment of SUA mimicking omega-shaped variant. Postnatal abdominal ultrasound and cardiac examination were unremarkable. This case suggests that the omega-shaped variant of SUA is probably a normal variant when unassociated with other structural anomalies. When a locally dilated umbilical artery is detected during routine 2D ultrasound, the authors recommend using 3D color Doppler imaging to more precisely determine the course of the umbilical artery.

INDUSTRIAL MATHEMATICS IN ULTRASOUND IMAGING

Ultrasound imaging is a widely used tool for visualizing human body's internal organs and quantifying clinical parameters. Due to its advantages such as safety, non-invasiveness, portability, low cost and real-time 2D/3D imaging, diagnostic ultrasound industry has steadily grown. Since the technology advancements such as digital beam-forming, Doppler ultrasound, real-time 3D imaging and automated diagnosis techniques, there are still a lot of demands for image quality improvement, faster and accurate imaging, 3D color Doppler imaging and advanced functional imaging modes. In order to satisfy those demands, mathematics should be used properly and effectively in ultrasound imaging. Mathematics has been used commonly as mathematical modelling, numerical solutions and visualization, combined with science and engineering. In this article, we describe a brief history of ultrasound imaging, its basic principle, its applications in obstetrics/gynecology, cardiology and radiology, domestic-industrial products, contributions of mathematics and challenging issues in ultrasound imaging.

Imaging Challenges in Secondary Mitral Regurgitation

Chronic secondary mitral regurgitation (SMR) is a complex entity that is often clinically underappreciated.1 It complicates either ischemic heart disease or dilated cardiomyopathy; its prevalence varies among series but may reach ≤50% in patients with heart failure.2 When present, SMR may exhibit a broad range of severity and confers an adverse prognosis, which is worse with increasing severity of mitral regurgitation (MR).3,4 The management of SMR poses a unique set of challenges, based partly on the complexity of the valve disorder and the still-evolving adoption of the optimal therapeutic approach.5 Noninvasive imaging and, in particular, echocardiography, plays a critical role for the initial and longitudinal assessment, for individual risk stratification and outcome prediction, and for guiding intervention in patients with chronic SMR.6 SMR develops because of a combination of mitral leaflet tethering secondary to left ventricular (LV) dilatation/deformation with papillary displacement/discoordination, annular dilatation/dysfunction, insufficient LV-generated closing forces attributable to reduction of LV contractility, and global LV/papillary muscle dyssynchrony.1,5 Tethering of the mitral leaflets is the principal lesion of SMR and results in restriction of systolic leaflet motion, namely type IIIb of Carpentier’s classification. SMR does not typically occur in global LV dysfunction without tethering. However, once tethering occurs, leaflet closure is further impaired by LV dysfunction because there is decreased force opposing tethering.6–9 The key event in the pathogenesis of SMR is the distortion of normal LV geometry—regional and global LV remodeling—with subsequent apical and lateral displacement of papillary muscles, which, in turn, draws the chordae tendineae away from the line of coaptation.7,8 The extent of LV systolic dysfunction and dilatation is weakly correlated to the degree of SMR unless accompanied by geometric distortion in the region of the papillary muscles.1,9 …

Proximal Flow Convergence Method by Three-Dimensional Color Doppler Echocardiography for Mitral Valve Area Assessment in Rheumatic Mitral Stenosis

The two-dimensional (2D) proximal isovelocity surface area (PISA) method has important technical limitations for mitral valve orifice area (MVA) assessment in mitral stenosis (MS), mainly the geometric assumptions of PISA shape and the requirement of an angle correction factor. Single-beat real-time three-dimensional (3D) color Doppler imaging allows the direct measurement of PISA without geometric assumptions or the requirement of an angle correction factor. The aim of this study was to validate this method in patients with rheumatic MS. Sixty-three consecutive patients with rheumatic MS were included. MVA was assessed using the transthoracic 2D and 3D PISA methods. Planimetry of MVA (2D and 3D) and the pressure half-time method were used as reference methods. The 3D PISA method had better correlations with the reference methods (with 2D planimetry, r = 0.85, P < .001; with 3D planimetry, r = 0.89, P < .001; and with pressure half-time, r = 0.85, P < .001) than the conventional 2D PISA method (with 2D planimetry, r = 0.63, P < .001; with 3D planimetry, r = 0.66, P < .001; and with pressure half-time, r = 0.68, P < .001). In addition, a consistent significant underestimation of MVA using the conventional 2D PISA method was observed. A high percentage (30%) of patients with nonsevere MS by 3D planimetry were misclassified by the 2D PISA method as having severe MS (effective regurgitant orifice area < 1 cm(2)). In contrast, the 3D PISA method had 94% agreement with 3D planimetry. Good intra- and interobserver agreement for 3D PISA measurements were observed, with intraclass correlation coefficients of 0.95 and 0.90, respectively. MVA assessment using PISA by single-beat real-time 3D color Doppler echocardiography is feasible in the clinical setting and more accurate than the conventional 2D PISA method.

Proximal Isovelocity Surface Area by Single-Beat Three-Dimensional Color Doppler Echocardiography Applied for Tricuspid Regurgitation Quantification

The two-dimensional (2D) proximal isovelocity surface area (PISA) method has known technical limitations, mainly the geometric assumptions of PISA shape required to calculate effective regurgitant orifice area (EROA). Recently developed single-beat real-time three-dimensional (3D) color Doppler imaging allows the direct measurement of PISA without geometric assumptions and has already been validated for mitral regurgitation assessment. The aim of this study was to apply this novel method in patients with chronic tricuspid regurgitation (TR). Ninety patients with chronic TR were enrolled. EROA and regurgitant volume (Rvol) were assessed using transthoracic 2D and 3D PISA methods. Quantitative Doppler and 3D transthoracic planimetry of EROA were used as reference methods. Both EROA and Rvol assessed using the 3D PISA method had better correlations with the reference methods than using conventional 2D PISA, particularly in the assessment of eccentric jets. On the basis of 3D planimetry-derived EROA, 35 patients had severe TR (EROA ≥ 0.4 cm(2)). Among these 35 patients, 25.7% (n = 9) were underestimated as having nonsevere TR (EROA ≤ 0.4 cm(2)) using the 2D PISA method. In contrast, the 3D PISA method had 94.3% agreement (33 of 35) with 3D planimetry in classifying severe TR. Good intraobserver and interobserver agreement for 3D PISA measurements was observed, with intraclass correlation coefficients of 0.92 and 0.88 respectively. TR quantification using PISA by single-beat real-time 3D color Doppler echocardiography is feasible in the clinical setting and more accurate than the conventional 2D PISA method.

Direct Measurement of Proximal Isovelocity Surface Area by Single-Beat Three-Dimensional Color Doppler Echocardiography in Mitral Regurgitation: A Validation Study

The two-dimensional (2D) proximal isovelocity surface area (PISA) method has some technical limitations, mainly the geometric assumptions of PISA shape required to calculate effective regurgitant orifice area (EROA). Recently developed single-beat, real-time three-dimensional (3D) color Doppler imaging allows direct measurement of PISA without geometric assumptions. The aim of this study was to validate this novel method in patients with chronic mitral regurgitation (MR). Thirty-three patients were included, 25 (75.7%) with degenerative MR and eight (24.2%) with functional MR. EROA and regurgitant volume were assessed using transthoracic 2D and 3D PISA methods. The quantitative Doppler method and 3D transesophageal echocardiographic planimetry of EROA were used as reference methods. Both EROA and regurgitant volume assessed using the 3D PISA method had better correlations with the reference methods than conventional 2D PISA. A consistent significant underestimation of EROA and regurgitant volume using 2D PISA was observed, particularly in the assessment of eccentric jets. On the basis of 3D transesophageal echocardiographic planimetry of EROA, 14 patients had severe MR (EROA ≥ 0.4 cm(2)). Of these 14 patients, 42.8% (6 of 14) were underestimated as having nonsevere MR (EROA ≤ 0.4 cm(2)) by the 2D PISA method. In contrast, the 3D PISA method had 92.9% (13 of 14) agreement with 3D transesophageal planimetry in classifying severe MR. Good intraobserver and interobserver agreement for 3D PISA measurements was observed, with intraclass correlation coefficients of 0.96 and 0.92, respectively. Direct measurement of PISA without geometric assumptions using single-beat, real-time 3D color Doppler echocardiography is feasible in the clinical setting. MR quantification using this methodology is more accurate than the conventional 2D PISA method.

Directional Color Doppler Aids the 2D and 3D Prenatal Diagnosis of Cleft Lip and Palate With Antenatal Single-Shot Fast-Spin Echo Magnetic Resonance Imaging Confirmation

Standard 2D sonography has variable success in the prenatal diagnosis of cleft lip combined with cleft palate. A case is presented that demonstrates the added value of 3D sonography plus color Doppler imaging in confirming this diagnosis. Additional techniques such as the flipped-face view, the reverse-face view, and the oblique-face view are discussed as further enhancements to the prenatal sonographic study of the fetal palate.

Quantifying Mitral Regurgitation: Added Value of Three-Dimensional Echocardiography

Current three-dimensional (3D) echocardiographic technology, including live 3D transesophageal echocardiography and single-beat 3D color Doppler imaging, are providing valuable new insight into the mechanism and quantification of mitral valve dysfunction. In this review we discuss important applications of 3D volumetric leaflet imaging with emphasis on the distinction between organic and functional mitral regurgitation. We also discuss the added benefit of current and emerging 3D color Doppler methods for the quantification of mitral regurgitation severity. The limitations of the 2D proximal isovelocity surface area method are discussed, along with potential solutions provided by 3D color Doppler imaging methods that do not require assumptions about the converging flow geometry. Methods to directly measure the vena contracta area of a regurgitant jet are presented along with recent validation studies comparing this method to a reference standard of cardiac MRI. In brief, we review the established and emerging applications of 3D color Doppler techniques for the quantification of mitral regurgitation severity.

Ultrasonic Studies on Amniotic Fluid Umbilical Cord and Placenta

ABSTRACT Detail evaluation of amniotic fluid, umbilical cord and placenta has been obtained by means of ultrasound new technology, including 3D color Doppler imaging. This paper summarizes fetal membrane anatomy and disorders using many ultrasound images taken by not only 2D gray scale ultrasound but also 3D color Doppler images.

Three-dimensional imaging of living transplanted kidney vasculature by 3D color Doppler ultrasonography

Abstract Background: It is of clinical importance to display the vasculature of transplanted kidney in three-dimensional (3D) and in non-invasive way. 3D color Doppler ultrasonographic imaging (3D-CDUI) is a non-invasive technique to display the 3D vasculature of living organs. Objective: Probe into characteristics of 3D vasculature of living transplanted kidney by 3D-CDUI, and evaluate the clinical value of 3D-CDUI on monitoring complications after operation of renal transplant. Methods: Nine patients who received allogeneic transplantation of kidney were monitored with 3D-CDUI. The instruments used included ACUSON Sequoia 512 and TomTec computer station of 3D-CDUI. Using magnetic positioning free-hand scanning, the 3D reconstruction and display of renal tissue structure and blood flow were performed off-line. Results: All patients underwent 3D-CDUI examinations without any side effect or complication. When acute rejection occurred, the 3D distribution change of renal blood flow signal could be observed clearly. During treatment of acute necrosis of renal tubules, changes of renal blood flow signal in 3D color Doppler images could be detected earlier compared with 2D color Doppler images. The position of embolized vassels could be diagnosed accurately by 3D-CDUI. Conclusion: The 3D-CDUI was helpful to improve diagnosis level of ultrasonography by monitoring complications after renal transplantation.

Prenatal features of a fetal frontal hemangioma assessed by 3D ultrasound and color Doppler imaging

Prenatal features of a fetal frontal hemangioma assessed by 3D ultrasound and color Doppler imaging

Adaptive Clutter Rejection for 3D Color Doppler Imaging: Preliminary Clinical Study

In three-dimensional (3D) ultrasound color Doppler imaging (CDI), effective rejection of flash artifacts caused by tissue motion (clutter) is important for improving sensitivity in visualizing blood flow in vessels. Since clutter characteristics can vary significantly during volume acquisition, a clutter rejection technique that can adapt to the underlying clutter conditions is desirable for 3D CDI. We have previously developed an adaptive clutter rejection (ACR) method, in which an optimum filter is dynamically selected from a set of predesigned clutter filters based on the measured clutter characteristics. In this article, we evaluated the ACR method with 3D in vivo data acquired from 37 kidney transplant patients clinically indicated for a duplex ultrasound examination. We compared ACR against a conventional clutter rejection method, down-mixing (DM), using a commonly-used flow signal-to-clutter ratio (SCR) and a new metric called fractional residual clutter area (FRCA). The ACR method was more effective in removing the flash artifacts while providing higher sensitivity in detecting blood flow in the arcuate arteries and veins in the parenchyma of transplanted kidneys. ACR provided 3.4 dB improvement in SCR over the DM method (11.4 ± 1.6 dB versus 8.0 ± 2.0 dB, p < 0.001) and had lower average FRCA values compared with the DM method (0.006 ± 0.003 versus 0.036 ± 0.022, p < 0.001) for all study subjects. These results indicate that the new ACR method is useful for removing nonstationary tissue motion while improving the image quality for visualizing 3D vascular structure in 3D CDI. (E-mail: ykim@u.washington.edu)

Placental vasculature as visualized by 3D power Doppler angiography and 3D color Doppler imaging

Placental vasculature as visualized by 3D power Doppler angiography and 3D color Doppler imaging

Geometry of the proximal isovelocity surface area in mitral regurgitation by 3-dimensional color Doppler echocardiography: Difference between functional mitral regurgitation and prolapse regurgitation

The geometry of the proximal isovelocity surface area (PISA) of functional mitral regurgitation (MR), which is conventionally assumed to be a hemisphere, remains to be clarified. We investigated the 3-dimensional (3D) geometry of PISA of functional MR as opposed to that of MR due to mitral valve prolapse (MVP) by real-time 3D echocardiography with color Doppler capability. Twenty-seven patients with functional MR and 27 patients with MVP were examined. The horizontal PISA length in the commissure-commissure plane and each PISA radius in 3 anteroposterior planes (medial, central, and lateral) were measured by real-time 3D echocardiography with 3D software. The effective regurgitant orifice (ERO) area was calculated with the maximum PISA radius and compared to that by 2D quantitative Doppler method. En-face 3D color Doppler images showed an elongated and slightly curved PISA geometry along the leaflet coaptation in functional MR, whereas the geometry was rounder in MVP. The PISA horizontal length in functional MR was longer than that in MVP (2.3 +/- 0.4 vs 1.2 +/- 0.2 cm, P < .001). The PISA method with the maximum radius underestimated the ERO area by 2D quantitative Doppler method (by 24%) in functional MR, but not in MVP. The geometry of PISA in functional MR was elongated, distinctly different from the more focal pathology of MVP, leading to underestimation of the ERO area by PISA method.

OP09.15: Prenatal features of a fetal frontal hemangioma assessed by 3D ultrasound and color Doppler imaging

OP09.15: Prenatal features of a fetal frontal hemangioma assessed by 3D ultrasound and color Doppler imaging

Cooperation of fuzzy segmentation operators for correction aliasing phenomenon in 3D color Doppler imaging

The study described in this paper concerns natural object modeling in the context of uncertain, imprecise and inconsistent representation. We propose a fuzzy system which offers a global modeling of object properties such as color, shape, velocity, etc. This modeling makes a transition from a low level reasoning (pixel level), which implies a local precise but uncertain representation, to a high level reasoning (region level), inducing a certain assignment. So, we use fuzzy structured partitions characterizing these properties. At this level. each property will have its own global modeling. Then, these different models are merged for decision making. Our approach was tested with several applications. In particular, we show here its performance in the area of blood flow analysis from 3D color Doppler images in order to quantify and study the development of this flow. We present methods that detect and correct aliasing phenomenon, i.e. inconsistent information. At first, the flow space is partitioned into fuzzy sectors where each sector is defined by a center, an angle and a direction. In parallel, the velocity information carried by the pixels is classified into fuzzy classes. Then, by combining these two partitions, we obtain the velocity distribution into sectors. Moreover, for each found path (from the first sector to the last one), we locate and correct inconsistent velocities by applying global rules. After extracting some meaningful sector features, the fuzzy modeling, applied to the aliasing correction, makes it possible to simplify and synthesize the blood flow direction.

頭蓋内血管性疾患の３次元カラードプラ画像とＣＴ ａｎｇｉｏｇｒａｐｈｙとの対比

To visualize the vascular anatomy of the brain, we have developed a system for producing three-dimensional (3D) color Doppler images from a series of two-dimensional color Doppler images. Two-dimensional images of cerebral vessels were digitized, and specially designed software reconstructed the 3D volumes and displayed volume-rendered images of the cerebral vessels during surgery for cases of aneurysm or arteriovenous malformation. Intraoperative 3D color Doppler images represented as cerebral vessels were successfully obtained from both of two patients. Especially in the patient with an aneurysm, 3D color flow images were equal in their displayed features to images obtained by CT angiography. We discuss the possibility of the applying ultrasound 3D imaging in patients with neurosurgical disorders.