Mitral valve analysis adding a virtual semi-transparent annulus plane for detection of prolapsing segments.

BACKGROUND: We hypothesized that a novel three-dimensional virtual semi-transparent annulus plane (3D VSAP) presented on a holographic screen can be used to visualize the prolapsing tissue in degenerative mitral valve disease and furthermore, provide us with geometrical data of the mitral valve apparatus. Phantom and patient studies were designed to demonstrate the feasibility of creating a semi-automatic, semi-transparent mitral annulus plane visualized on a holographic display. METHODS: Ten pipe cleaners mimicking the mitral annulus with different shapes and three types of annuloplasty rings served as phantoms. We obtained 3D transoesophageal examination of the phantoms in a special designed box filled with water. Recordings were converted to the holographic display and a 3D VSAP was created. The ratio of the major and minor axes as well as the non-planar angles were calculated and compared with direct measures of the phantoms. Forty patients with degenerative mitral valve disease were then analyzed with 3D transthoracic echocardiography (TTE) and a 3D VSAP was created on the holographic display. A total of 240 segments were analyzed by two independent observers, one echo expert (observer I), and the other novice with limited echo experience (observer II). The two observers created the 3D VSAP in each patient before suggesting the valve pathology. RESULTS: The major/minor axes ratio and non-planar angles by 3D VSAP correlated with direct measurements by r = 0.65, p < 0.02 and r = 0.99, p < 0.0001, respectively. The sensitivity and specificity of the 3D VSAP method in patients was 81 and 97%, respectively (observer I) and for observer II 77 and 96%, respectively. The accuracy and precisions were 93.9 and 89.4%, respectively (observer I), 92.3 and 85.1% (observer II). Mitral valve analysis adding a 3D VSAP was feasible with high accuracy and precision, providing a quick and less subjective method for diagnosing mitral valve prolapse. This novel method may improve preoperative diagnostics and may relieve a better understanding of the pathophysiology of mitral valve disease. Thus, based on the specific findings in each patient, a tailored surgical repair can be planned and hopefully enhance long-term repair patency in the future.

Mitral valve analysis using a novel 3D holographic display: a feasibility study of 3D ultrasound data converted to a holographic screen.

The aim of the present study was to test the feasibility of analyzing 3D ultrasound data on a novel holographic display. An increasing number of mini-invasive procedures for mitral valve repair require more effective visualization to improve patient safety and speed of procedures. A novel 3D holographic display has been developed and may have the potential to guide interventional cardiac procedures in the near future. Forty patients with degenerative mitral valve disease were analyzed. All had complete 2D transthoracic (TTE) and transoesophageal (TEE) echocardiographic examinations. In addition, 3D TTE of the mitral valve was obtained and recordings were converted from the echo machine to the holographic screen. Visual inspection of the mitral valve during surgery or TEE served as the gold standard. 240 segments were analyzed by 2 independent observers. A total of 53 segments were prolapsing. The majority included P2 (31), the remaining located at A2 (8), A3 (6), P3 (5), P1 (2) and A1 (1). The sensitivity and specificity of the 3D display was 87 and 99 %, respectively (observer I), and for observer II 85 and 97 %, respectively. The accuracies and precisions were 96.7 and 97.9 %, respectively, (observer I), 94.3 and 88.2 % (observer II), and inter-observer agreement was 0.954 with Cohen's Kappa 0.86. We were able to convert 3D ultrasound data to the holographic display. A very high accuracy and precision was shown, demonstrating the feasibility of analyzing 3D echo of the mitral valve on the holographic screen.

An autostereoscopic 3D display can improve visualization of 3D models from intracranial MR angiography.

PURPOSE: An autostereoscopic display with image quality comparable to ordinary 2D displays has recently been developed. The purpose of our study was to evaluate whether the visualization of static 3D models from intracranial time-of-flight (TOF) MR angiography (MRA) was improved by this display. METHODS: Maximum Intensity Projection (MIP) and Volume Rendering (VR) 3D models of intracranial arteries were created from ten TOF MRA datasets. Thirty-one clinically relevant intracranial arterial segments were marked in the TOF source images. A total of 217 markings were used. The markings were displayed in the 3D models as overlying red dots. Three neuroradiologists viewed the static 3D models on the autostereoscopic display, with the display operating either in autostereoscopic mode or in 2D mode. The task of the neuroradiologists was to correctly identify the marked artery. A paired comparison was made between arterial identification in autostereoscopic and 2D display mode. RESULTS: In 314 MIP 3D models, 233 arterial markings (74%) were correctly identified with the display operating in autostereoscopic mode versus 179 (57%) in 2D mode. Odds ratio for correct identification with autostereoscopic mode versus 2D mode was 2.17 (95% confidence interval 1.55-3.04, P < 0.001). In 337 VR 3D models, 256 markings (76%) were correctly identified using autostereoscopic mode and 229 (68%) using 2D mode (odds ratio 1.49, 95% confidence interval 1.06-2.09, P = 0.021). CONCLUSION: The visualization of intracranial arteries in static 3D models from TOF MRA can be improved by the use of an autostereoscopic display.