Four-dimensional echocardiography with spatiotemporal image correlation and inversion mode for detection of congenital heart disease

MR and ultrasound cardiac image dynamic visualization and synchronization over Internet for distributed heart function diagnosis

Dual-modality 4D cardiac data visualization can convey a significant amount of complementary image information from various sources into a single and meaningful display. Even though there are existing publications on combining multiple medical images into a unique representation, there has been no work on rendering a series of cardiac image sequences, acquired from multiple sources, using web browsers and synchronizing the result over the Internet in real time. The ability to display multi-modality beating heart images using Web-based technology is hampered by the lack of efficient algorithms for fusing and visualizing constantly updated multi-source images and streaming the rendering results using internet protocols. To address this practical issue, in this paper we introduce a new Internet-based algorithm and a software platform running on a Node.js server, where a series of registered cardiac images from both magnetic resonance (MR) and ultrasound are employed to display dynamic fused cardiac structures in web browsers. Taking advantage of the bidirectional WebSocket protocol and WebGL-based graphics acceleration, internal cardiac structures are dynamically displayed, and the results of rendering and data exploration are synchronized among all the connected client computers. The presented research and software have the potential to provide clinicians with comprehensive information and intuitive feedback relating to cardiac behavior and anatomy and could impact areas such as distributed diagnosis of cardiac function and collaborative treatment planning for various heart diseases.

Fetal Vascular Rings and Pulmonary Slings: Strategies for Two- and Three-Dimensional Echocardiographic Diagnosis

Fetal aortic arch anomalies and pulmonary slings can be difficult to accurately diagnose but have important clinical implications related to vascular rings, congenital heart disease, and chromosomal anomalies. In this article, the authors briefly review the embryology and development of the fetal arch to facilitate understanding of its diverse variants. Two-dimensional echocardiographic characteristics are summarized for each type of these malformations to propose a strategy for fetal diagnosis. The added benefits of three-dimensional echocardiography with spatiotemporal image correlation are also shown. Finally, the authors propose a strategy for volume acquisition and postanalysis to spur postanalysis clinical use of this technology.

4D fetal echocardiography-An update

With the introduction of the electronic 4-dimensional and spatial-temporal image Correlation (e-STIC), it is now possible to obtain large volume datasets of the fetal heart that are virtually free of artifact. This allows the examiner to use a number of imaging modalities when recording the volumes that include two-dimensional real time, power and color Doppler, and B-flow images. Once the volumes are obtained, manipulation of the volume dataset allows the examiner to recreate views of the fetal heart that enable examination of cardiac anatomy. The value of this technology is that a volume of the fetal heart can be obtained, irrespective of the position of the fetus in utero, and manipulated to render images for interpretation and diagnosis. This article presents a summary of the various imaging techniques and provides clinical examples of its application used for prenatal diagnosis of congenital heart defects and abnormal cardiac function.

Cardiac and respiratory-gated volumetric murine ultrasound

Current cardiovascular ultrasound mainly employs planar imaging techniques to assess function and physiology. These techniques rely on geometric assumptions, which are dependent on the imaging plane, susceptible to inter-observer variability, and may be inaccurate when studying complex diseases. Here, we developed a gated volumetric murine ultrasound technique to visualize cardiovascular motion with high spatiotemporal resolution and directly evaluate cardiovascular health. Cardiac and respiratory-gated cine loops, acquired at 1000 frames-per-second from sequential positions, were temporally registered to generate a four-dimensional (4D) dataset. We applied this technique to (1) evaluate left ventricular (LV) function from both healthy mice and mice with myocardial infarction and (2) characterize aortic wall strain of angiotensin II-induced dissecting abdominal aortic aneurysms in apolipoprotein E-deficient mice. Combined imaging and processing times for the 4D technique was approximately 2-4 times longer than conventional 2D approaches, but substantially more data is collected with 4D ultrasound and further optimization can be implemented to reduce imaging times. Direct volumetric measurements of 4D cardiac data aligned closely with those obtained from MRI, contrary to conventional methods, which were sensitive to transducer alignment, leading to overestimation or underestimation of estimated LV parameters in infarcted hearts. Green-Lagrange circumferential strain analysis revealed higher strain values proximal and distal to the aneurysm than within the aneurysmal region, consistent with published reports. By eliminating the need for geometrical assumptions, the presented 4D technique can be used to more accurately evaluate cardiac function and aortic pulsatility. Furthermore, this technique allows for the visualization of regional differences that may be overlooked with conventional 2D approaches.

Evaluation of fetal cardiac valve anomalies by four-dimensional echocardiography with spatiotemporal image correlation (4DSTIC)

BACKGROUND

Prenatal diagnosis of cardiac valve anomalies challenged most screening sonographers. The purpose of the study was to evaluate the use of four-dimensional echocardiography with spatiotemporal image correlation (4DSTIC) in detecting normal and abnormal fetal cardiac valves.

METHODS

Forty-three cases of confirmed cardiac valve anomalies identified by two-dimensional echocardiography (2DE) were retrospectively reviewed in this study. Additional 121 confirmed normal fetuses were included as controls. Four-dimensional volumes were acquired from each fetus using a transverse sweep. Four-dimensional rendered images were retrieved from the volumes for each of the cardiac valves for the normal fetuses and for the intended valves for fetuses with valve malformations.

RESULTS

The visualization rates of cardiac valves retrieved from 4D volumes in the normal fetuses ranged from 72.5% to 97.5% before 33 gestational weeks and from 46.3% to 80.5% in late pregnancy. Furthermore, 4D rendered images were successfully obtained in 38 of 43 (88.4%) fetuses with cardiac valve lesions.

CONCLUSIONS

The 4D images and cine loops displayed the valves anatomy vividly in both normal and abnormal fetuses, including some subtle malformations which were not identified by traditional 2DE. The standardized protocol we propose herein was important in obtaining the 4D images from the volumes. The 4D modality allows a better visualization of fetal cardiac valves and should be considered a valuable addition to traditional 2DE imaging.

A Prospective Study of the Use of Fetal Intelligent Navigation Echocardiography (FINE) to Obtain Standard Fetal Echocardiography Views

OBJECTIVE

To evaluate the performance of Fetal Intelligent Navigation Echocardiography (FINE) applied to spatiotemporal image correlation (STIC) volume datasets of the normal fetal heart in generating standard fetal echocardiography views.

METHODS

In this prospective cohort study of patients with normal fetal hearts (19-30 gestational weeks), one or more STIC volume datasets were obtained of the apical four-chamber view. Each STIC volume successfully obtained was evaluated by STICLoop™ to determine its appropriateness before applying the FINE method. Visualization rates for standard fetal echocardiography views using diagnostic planes and/or Virtual Intelligent Sonographer Assistance (VIS-Assistance®) were calculated.

RESULTS

One or more STIC volumes (total n = 463) were obtained from 246 patients. A single STIC volume per patient was analyzed using the FINE method. In normal cases, FINE was able to generate nine fetal echocardiography views using: (1) diagnostic planes in 76-100% of the cases, (2) VIS-Assistance® in 96-100% of the cases, and (3) a combination of diagnostic planes and/or VIS-Assistance® in 96-100% of the cases.

CONCLUSION

FINE applied to STIC volumes can successfully generate nine standard fetal echocardiography views in 96-100% of cases in the 2nd and 3rd trimesters. This suggests that the technology can be used as a method of screening for congenital heart disease.

How to Acquire Cardiac Volumes for Sonographic Examination of the Fetal Heart: Part 2

The effective performance of fetal cardiac examination using spatiotemporal image correlation (STIC) technology requires 2 essential steps: volume acquisition and postprocessing. An important prerequisite is training sonologists to acquire high-quality volume data sets so that when analyzed, such volumes are informative. This article is part 2 of a series on 4-dimensional sonography with STIC. Part 1 focused on STIC technology and its features, the importance of operator training/experience and acquisition of high-quality STIC volumes, factors that affect STIC volume acquisition rates, and general recommendations on performing 4D sonography with STIC. In part 2, we discuss a detailed and practical stepwise approach for STIC volume acquisition, along with methods to determine whether such volumes are appropriate for analysis.

How to Acquire Cardiac Volumes for Sonographic Examination of the Fetal Heart: Part 1

Four-dimensional sonography with spatiotemporal image correlation (STIC) technology allows acquisition of a fetal cardiac volume data set and displays a cine loop of a complete single cardiac cycle in motion. Part 1 of this 2-part article reviews STIC technology and its features, the importance of operator training/experience, and acquisition of high-quality STIC volumes, as well as factors that affect STIC volume acquisition rates. We also propose a detailed and practical stepwise approach to performing 4-dimensional sonography with STIC and begin herein by providing general recommendations. Part 2 will discuss specifics of the approach, along with how to determine whether such volumes are appropriate for analysis.

Prospective evaluation of the fetal heart using Fetal Intelligent Navigation Echocardiography (FINE)

OBJECTIVE

To evaluate prospectively the performance of Fetal Intelligent Navigation Echocardiography (FINE) applied to spatiotemporal image correlation (STIC) volume datasets of the normal fetal heart.

METHODS

In all women between 19 and 30 weeks' gestation with a normal fetal heart, an attempt was made to acquire STIC volume datasets of the apical four-chamber view if the following criteria were met: (1) fetal spine located between 5- and 7-o'clock positions; (2) minimal or absent shadowing (including a clearly visible transverse aortic arch); (3) absence of fetal breathing, hiccups, or movement; and (4) adequate image quality. Each STIC volume successfully acquired was evaluated by STICLoop™ to determine its appropriateness before applying the FINE method. Visualization rates of fetal echocardiography views using diagnostic planes and/or Virtual Intelligent Sonographer Assistance (VIS-Assistance®) were calculated.

RESULTS

One or more STIC volumes (365 in total) were obtained successfully in 72.5% (150/207) of women undergoing ultrasound examination. Of the 365 volumes evaluated by STICLoop, 351 (96.2%) were considered to be appropriate. From the 351 STIC volumes, only one STIC volume per patient (n = 150) was analyzed using the FINE method, and consequently nine fetal echocardiography views were generated in 76-100% of cases using diagnostic planes only, in 98-100% of cases using VIS-Assistance only, and in 98-100% of cases when using a combination of diagnostic planes and/or VIS-Assistance.

CONCLUSIONS

In women between 19 and 30 weeks' gestation with a normal fetal heart undergoing prospective sonographic examination, STIC volumes can be obtained successfully in 72.5% of cases. The FINE method can be applied to generate nine standard fetal echocardiography views in 98-100% of these cases using a combination of diagnostic planes and/or VIS-Assistance. This suggests that FINE could be implemented in fetal cardiac screening programs. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.