Ultrasound
White paper

Photorealistic imaging enhances
3D echocardiography in structuralinterventional cardiology
Dr. Jeffrey S K ChanResearcher, Prince of Wales Hospital, Hong Kong, China
Professor Alex Lee
Professor of Medicine and Therapeutics, Chinese University of Hong Kong
Director, Echocardiography Laboratory
Prince of Wales Hospital, Hong Kong, China

Overview
Three-dimensional (3D) echocardiography has become an essential imaging
technique in structural heart disease intervention. Today, the spectrumof diseases that the heart team has to deal with are increasingly complex,
as are the available interventional procedures and devices with whichto treat heart disease. Optimal methods for displaying 3D images are critical
for the perception of depth and to provide a clinically useful understandingof dynamic cardiac anatomy.
TrueVue photorealistic imaging
Conventional 3D rendering uses shading techniques toencode voxels based on their distance, gray-level gradientand texture to generate a 3D display of cardiac structures.
Philips TrueVue photorealistic 3D imaging goes beyond
this, simulating the interaction of light with tissue, whichenables users to illuminate structures within the volume(Figure 1).

Figure 1 TrueVue adds a virtual light source and simulates light-tissue
interactions, including absorption, scattering and reflection, resulting
in a photorealistic image with shadows that highlight structuresand enhance depth perception.

TrueVue
image

ViewerLight

Utrasounddata setThis printed copy is not an official Philips hard copy, use for reference only

TrueVue provides shadows to facilitate depth perception
and motion, improving visualization of the device during
an interventional procedure through the use of a virtual
light source and a physical model of how light interacts
with tissue. With an increase in computing power, thebehavior of different wavelengths of light can now bemodeled to generate a more realistic image (Figure 2).

With TrueVue, the light can be placed anywhere
within the volume to illuminate specific structures.
This photorealistic imaging enhances the sense of depth
and space, producing images that appear more naturaland realistic to the human eye, which facilitates thedetection of subtle structures and pathologies (Figure 3).

Light absorption

10.8
0.6
0.40.2005101520
Distance of penetration

2530

Io
Figure 2 Absorption of light in tissue is wavelength-dependent.
TrueVue models this dependency, resulting in darker red hueswith increased penetration depth.

Figure 3 Depiction of TrueVue shadows and scattering demonstrated ona synthetic and a clinical example. The lighting model results in shadowingthat transitions smoothly between illuminated and occluded regions.

Case studies
Four cases in which photorealistic imaging aided diagnosis for our team.

Case 1
Degenerative mitral regurgitation
3D transesophageal echocardiography (TEE) showsthe “surgeon’s perspective” of a case involving diffuse
degenerative mitral valve disease. TrueVue photorealistic
imaging (right panel) with the light source placed inside
the left atrium enhances the virtual shadowing of theprolapsed segments and allows for visualization of aruptured tendinous cord (arrow) of the A1 segment, ascompared to the conventional 3D TEE image (left panel).

3D standard rendering

TrueVue image

Enhanced visualization in diffuse degenerative mitral valve disease.

This printed copy is not an official Philips hard copy, use for reference only2

Case 2
Obstructive mechanical mitral prosthesis
A patient with a previous mechanical mitral valve
replacement underwent 3D TEE for evaluation of
the prosthetic valve with abnormal pressure gradient.
Upon conventional 3D TEE, it was suspected that the openingof one of the two mechanical leaflets was obstructed (leftpanel). Photorealistic imaging (right panel) with the TrueVue
virtual light source positioned in the left ventricle showstransillumination through the unobstructed orifice (red arrow)with the mobile leaflet, but not through the obstructed orificewith a leaflet stuck in the closed position (white arrow) as aresult of pannus overgrowth. Compared to the conventional
3D TEE image, transillumination imaging increases thediagnostic confidence of identifying an obstructive mitralvalve prosthesis.

3D standard rendering

TrueVue image

Transillumination aids in identifying an obstructive mitral valve prosthesis.

Case 3
Paravalvular leak of bioprosthetic mitral valve
A patient with a previous mitral bioprosthetic mitral valve
replacement underwent TEE for dyspnea on exertion,revealing a paravalvular leak on the posterolateral aspectof the prosthesis. Photorealistic 3D TEE imaging (rightupper panel) with virtual light projection from the left
ventricle clearly demonstrated the anatomy and locationof the paravalvular leak (asterisk in right upper panel), with
two loose surgical stitches (arrows in right upper panel),
which were presumably the cause of the dehiscence,
adjunct to conventional 3D rendering (left upper panel).
Transcatheter closure of the paravalvular leak wasperformed with two vascular plugs. Post-implantation
photorealistic 3D TEE with the TrueVue virtual light source
placed inside the left atrium confirms sealing of theparavalvular leak.

3D standard rendering

TrueVue image

The shadows projected by the vascular plugs on the mitral bioprosthesis(arrows in right lower panel) enhance discernment of the proper alignment
between the devices.

Case 4
Cryptogenic stroke
A patient underwent TEE with intravenous agitatedsaline contrast for evaluation of a suspected patent foramen
ovale (PFO) as a cause of cryptogenic stroke. The images
show the interatrial septum on 3D TEE from the left atrial
perspective. Compared to traditional 3D TEE (left panel),TrueVue photorealistic 3D TEE (right panel) more clearlyshows the agitated saline contrast passage through thefree edge of a PFO (arrow) on Valsalva release, highlighting
the anatomy of PFO flap and the number of bubbles
appearing in the left atrium.
3D standard rendering

TrueVue image

Visualization of contrast bubbles and anatomy aids evaluation of the causeof cryptogenic stroke.

3
This printed copy is not an official Philips hard copy, use for reference onlyConclusion
TrueVue photorealistic imaging in 3D echocardiography can enhance theinterpretation of structural heart disease images and improve communication
within the heart team. In many cases this imaging technique can provide
crucial clinical information that strengthens understanding of the anatomyand pathology, and alters management for improved patient outcomes.

Dr. Jeffrey S K ChanDr. Chan is responsible for the clinical management ofgeneral medical diseases, and conducts research inechocardiography, structural cardiac interventions andheart failure as part of Professor Alex Lee’s research teamat the Prince of Wales Hospital, Hong Kong, China.

Professor Alex Lee
Professor Lee is Professor of Medicine and Therapeutics
at the Chinese University of Hong Kong. He is also
Director, Echocardiography Laboratory, at the Prince ofWales Hospital, Hong Kong, China, where he performs
interventional and peri/intra-operative echocardiography.
He focuses on the clinical management of valvular disease,coronary artery disease and heart failure

Results from case studies are not predictive of results in other cases. Results in other cases may vary.

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