Improved Delineation of Cardiac Pathology Using a Novel Three-Dimensional Echocardiographic Tissue Transparency Tool

Abstract

Background: Accurate visualization of cardiac valves and lesions by three-dimensional (3D) echocardiography is integral for optimal guidance of structural procedures and appropriate selection of closure devices. A new 3D rendering tool known as transillumination (TI), which integrates a virtual light source into the data set, was recently reported to effectively enhance depth perception and orifice definition. We hypothesized that adding the ability to adjust transparency to this tool would result in improved visualization and delineation of anatomy and pathology and improved localization of regurgitant jets compared with TI without transparency and standard 3D rendering.

Methods: We prospectively studied 30 patients with a spectrum of structural heart disease who underwent 3D transesophageal imaging (EPIQ system, Philips) with standard acquisition and TI with and without the transparency feature. Six experienced cardiologists and sonographers were shown randomized images of all three display types in a blinded fashion. Each image was scored independently by all experts using a Likert scale from 1 to 5, while assessing each of the following aspects: (1) ability to recognize anatomy, (2) ability to identify pathology, including regurgitant jet origin, (3) depth perception, and (4) quality of border delineation.

Results: TI images with transparency were successfully obtained in all cases. All experts perceived an incremental value of the transparency mode, compared with TI without transparency and standard 3D rendering, in terms of ability to recognize anatomy (respective scores: 4.5 ± 1.1 vs 4.1 ± 1.1 vs 3.6 ± 1.1, P < .05), ability to identify pathology (4.1 ± 1.1 vs 3.9 ± 1.2 vs 3.3 ± 1, P < .05), depth perception (4.6 ± 0.7 vs 4.1 ± 0.8 vs 3.2 ± 1.0, P < .05), and border delineation (4.6 ± 0.8 vs 4.1 ± 1.0 vs 3.1 ± 1.1, P < .05).

Conclusions: The addition of the transparency mode to TI rendering significantly improves the diagnostic and clinical utility of 3D echocardiography and has the potential to markedly enhance echocardiographic guidance of cardiac structural interventions.

Keywords: Three-dimensional echocardiography; Transillumination; Valvular heart disease.

Figure 1

(A) Standard 3D TEE rendering of LAA at 0° prior to placement of a Watchman LAA occluder device. (B) LAA displayed using TI technique. (C) LAA shown using new 3D transparency tool, which allowed us to appreciate the windsock shape of the LAA, as well as to more accurately assess the LAA ostial diameter for optimal sizing of the LAA occluder device. Images B and C were obtained from image A using the rendering techniques described above.

Figure 2

Ischemic mitral regurgitation. (A) Standard 3D TEE rendering of mitral valve (MV) from the left atrial perspective (surgeon’s view) in end diastole demonstrating malcoaptation due to ischemic MV disease. (B) TI of the MV with light source positioned through the area of malcoaptation. (C) Three-dimensional transparency feature clearly delineating the borders and shape of the MV orifice as well as the area of malcoaptation just medial to A2-P2. (D) Three-dimensional transparency feature merged with 3D color Doppler demonstrating flow acceleration through the MV, allowing for calculation of effective regurgitant orifice area using 3D proximal isovelocity surface area. Images B, C, and D were obtained from image A using the rendering techniques described above. A1, A1 scallop of MV; A2, A2 scallop of MV; A3, A3 scallop of MV; LA, left atrium; LV, left ventricle; P1, P1 scallop of MV; P2, P2 scallop of MV; P3, P3 scallop of MV.

Figure 3

Mitral bioprosthetic paravalvular leak. (A) Mitral bioprosthetic valve displayed using standard 3D TEE rendering with suggestion of a paravalvular leak at the five o’clock position (blue arrow). (B) TI technique with virtual light source demonstrating the location of the paravalvular leak (blue arrow). (C) Three-dimensional transparency technique more clearly delineating the borders and edges of the paravalvular leak at the five o’clock position (blue arrow). With the aid of this information, the interventional cardiologist was able to place several percutaneous closure devices in the exact area of the paravalvular leak. Images B and C were obtained from image A using the rendering techniques described above.

Figure 4

Posteromedial commissural prolapse and perforation. (A) Standard 3D TEE rendering of the mitral valve (MV) from the left atrial perspective (surgeon’s view) showing flail posteromedial commissure (PMC) of the MV. (B) TI highlighting PMC flail with associated perforation with the aid of a virtual light source through the perforated segment (white arrow). (C) Three-dimensional transparency feature redemonstrating flail P3 segment and PMC as well as more clearly delineating the perforation in the PMC (white arrow). (D) Three-dimensional transparency feature merged with 3D color demonstrating an eccentric mitral regurgitation jet that originates from the PMC and is directed in a medial to lateral direction (blue dotted arrow, white arrow). Images B, C, and D were obtained from image A using the rendering techniques described above. A1, A1 scallop of MV; A2, A2 scallop of MV; A3, A3 scallop of MV; P1, P1 scallop of MV; P2, P2 scallop of MV; P3, P3 scallop of MV.

Figure 5

LAA post-Watchman. (A) En face view of LAA using standard 3D TEE rendering following deployment of a 24 mm Watchman LAA occluder device (Boston Scientific; blue arrow), with suggestion of a possible leak at the three o’clock position (white arrow). (B) LAA occluder displayed using TI technique with virtual light source through area of peridevice leak (blue arrow). (C) Three-dimensional transparency tool clearly delineating the origin of the leak around the Watchman device (white arrow). (D) Three-dimensional transparency tool merged with 3D color clearly demonstrating color flow through the area of peridevice leak at the three o’clock position. This patient was thus continued on anticoagulation and followed closely with serial TEEs after his Watchman procedure with ultimate resolution of the peridevice leak. Images B, C, and D were obtained from image A using the rendering techniques described above. Ao, Aorta.

Figure 6

Degenerative mitral valve (MV) disease. (A) Standard 3D TEE rendering of the MV from the left atrial perspective (surgeon’s view) showing prolapsed P2 segment of the posterior MV leaflet. (B) TI highlighting P2 prolapse with a virtual light source through the prolapsed segment. (C) Three-dimensional transparency feature more clearly demonstrating the borders and shape of the prolapsed P2 segment. This patient subsequently underwent a successful MitraClip procedure with a clip placed in the A2-P2 region. Images B and C were obtained from image A using the rendering techniques described above. A1, A1 scallop of MV; A2, A2 scallop of MV; A3, A3 scallop of MV; P1, P1 scallop of MV; P2, P2 scallop of MV; P3, P3 scallop of MV.

Figure 7

Post MitraClip. (A) Standard 3D TEE rendering of the mitral valve (MV) showing the tissue bridge from left atrial perspective (surgeon’s view) following placement of two MitraClip NT devices (white arrow) in the A2-P2 region of the MV for treatment of severe, functional mitral regurgitation. (B) Alfieri stitch depicted using TI technique. (C) Three-dimensional transparency feature more vividly displays the borders and edges of the newly created dual MV orifice as well as the location of the two MitraClips in the A2-P2 region. (D) Increasing the degree of tissue transparency provides a translucent view of the MV and shows the MitraClip extending into the left ventricle, thus providing a greater degree of depth perception. Images B, C, and D were obtained from image A using the rendering techniques described above. A1, A1 scallop of MV; A2, A2 scallop of MV; A3, A3 scallop of MV; Ao, Aorta; P1, P1 scallop of MV; P2, P2 scallop of MV; P3, P3 scallop of MV.

Figure 8

(A) Interatrial septum depicted from right atrial perspective using standard 3D TEE rendering showing presence of ostium secundum ASD (blue arrow). (B) TI technique with virtual light source through ASD (blue arrow). (C) Three-dimensional transparency technique more clearly depicting the borders, edges, and shape of the ostium secundum ASD (blue arrow). (D) Three-dimensional transparency technique merged with 3D color showing interatrial color flow and evidence of left-to-right shunt through ostium secundum ASD. Images B, C, and D were obtained from image A using the rendering techniques described above. LA, Left atrium; RA, right atrium.

Figure 9

The four most common types of LAA morphologies, including (A) windsock, (B) chicken wing, (C) broccoli, and (D) cactus, depicted using TI with transparency mode next to their real-life counterparts for reference. Using this new technology, the degree of tissue transparency can be optimized to enable detailed visualization of the LAA anatomy, including internal ridges, lobes, and folds.