Clinical Implications of Three-Dimensional Real-Time Color Doppler Transthoracic Echocardiography in Quantifying Mitral Regurgitation: A Comparison with Conventional Two-Dimensional Methods.

BACKGROUND: Automatic quantification of real-time three-dimensional (3D) full-volume color Doppler transthoracic echocardiography (FVCD) has been proposed as a feasible and accurate method for quantifying MR. We aimed to explore the clinical implications of real-time 3D-FVCD for mitral regurgitation (MR) with various clinical manifestations, in comparison with the conventional two-dimensional (2D) proximal isovelocity surface area (PISA) and volumetric method and cardiac magnetic resonance imaging (CMR) methods. METHODS: A total 186 patients with MR were enrolled prospectively. Based on exclusion criteria and image quality review, 152 patients were included in the final analysis for 3D-FVCD and 2D transthoracic echocardiography. Among them, 37 patients underwent subsequent CMR for the validation of 3D-FVCD. RESULTS: MR volume from 3D-FVCD demonstrated a better agreement (r = 0.94) with CMR than 2D-PISA or the 2D volumetric method (VM; r = 0.87 vs 0.56). Overall, 2D methods underestimated MR when compared with 3D-FVCD (35.4 ± 28.4 mL for 2D-VM vs 43.8 ± 24.6 mL for 2D-PISA vs 64.6 ± 35.1 mL for 3D-FVCD; P < .001). In subgroup analysis, multijet MR (odds ratio [OR], 6.30; 95% CI, 2.52-15.72) and dilated left ventricular end-systolic diameter ≥40 mm (OR, 2.90; 95% CI, 1.12-7.50) were predictors of significant difference in MR volume (>30 mL for primary MR and >15 mL for secondary MR) between 2D-PISA and 3D-FVCD. In identifying surgical candidates, patients with multijet MR (OR, 4.53, 95% CI, 1.99-10.35) demonstrated a higher risk of discrepancy between 2D-PISA and 3D-FVCD, which were consistent in both primary and secondary MR, respectively. CONCLUSIONS: MR quantification with 3D-FVCD showed better correlation and agreement than conventional 2D methods. MR was underestimated by 2D methods, especially in multijet and dilated left ventricle. Multijet MR demonstrated higher risk of discrepancy for the identification of surgical candidate, regardless of MR etiology.

Effects of right ventricular hemodynamic burden on intraventricular flow in tetralogy of fallot: an echocardiographic contrast particle imaging velocimetry study.

BACKGROUND: The purpose of this investigation was to test the hypothesis that flow patterns in the right ventricle are abnormal in patients with repaired tetralogy of Fallot (TOF). High-resolution echocardiographic contrast particle imaging velocimetry was used to investigate rotation intensity and kinetic energy dissipation of right ventricular (RV) flow in patients with TOF compared with normal controls. METHODS: Forty-one subjects (16 with repaired TOF and varying degrees of RV dilation and 25 normal controls) underwent prospective contrast imaging using the lipid-encapsulated microbubble (Definity) on Sequoia systems. A mechanical index of 0.4, three-beat high-frame rate (>60 Hz) captures, and harmonic frequencies were used. Rotation intensity and kinetic energy dissipation of flow in the right and left ventricles were studied (Hyperflow). Ventricular volumes and ejection fractions in all subjects were derived from same-day cardiac magnetic resonance (CMR). RESULTS: Measurable planar maps were obtained for the left ventricle in 14 patients and the right ventricle in 10 patients among those with TOF and for the left ventricle in 23 controls and the right ventricle in 21 controls. Compared with controls, the TOF group had higher RV indexed end-diastolic volumes (117.8 ± 25.5 vs 88 ± 15.4 mL/m(2), P < .001) and lower RV ejection fractions (44.6 ± 3.6% vs 51.8 ± 3.6%, P < .001). Steady-streaming (heartbeat-averaged) flow rotation intensities were higher in patients with TOF for the left ventricle (0.4 ± 0.13 vs 0.29 ± 0.08, P = .012) and the right ventricle (0.53 ± 0.15 vs 0.26 ± 0.12, P < .001), whereas kinetic energy dissipation in TOF ventricles was lower (for the left ventricle, 0.51 ± 0.29 vs 1.52 ± 0.69, P < .001; for the right ventricle, 0.4 ± 0.24 vs 1.65 ± 0.91, P < .001). CONCLUSIONS: It is feasible to characterize RV and left ventricular flow parameters and planar maps in adolescents and adults with repaired TOF using echocardiographic contrast particle imaging velocimetry. Intraventricular flow patterns in the abnormal and/or enlarged right ventricle in patients with TOF differ from those in normal young adults. The rotation intensity and energy dissipation trends in this investigation suggest that they may be quantitative markers of RV and left ventricular compliance abnormalities in patients with repaired TOF. This hypothesis merits further investigation.

Toward multiple catheters detection in fluoroscopic image guided interventions.

Catheters are routinely inserted via vessels to cavities of the heart during fluoroscopic image guided interventions for electrophysiology (EP) procedures such as ablation. During such interventions, the catheter undergoes nonrigid deformation due to physician interaction, patient's breathing, and cardiac motions. EP clinical applications can benefit from fast and accurate automatic catheter tracking in the fluoroscopic images. The typical low quality in fluoroscopic images and the presence of other medical instruments in the scene make the automatic detection and tracking of catheters in clinical environments very challenging. Toward the development of such an application, a robust and efficient method for detecting and tracking the catheter sheath is developed. The proposed approach exploits the clinical setup knowledge to constrain the search space while boosting both tracking speed and accuracy, and is based on a computationally efficient framework to trace the sheath and simultaneously detect one or multiple catheter tips. The algorithm is based on a modification of the fast marching weighted distance computation that efficiently calculates, on the fly, important geodesic properties in relevant regions of the image. This is followed by a cascade classifier for detecting the catheter tips. The proposed technique is validated on 1107 fluoroscopic images acquired on multiple patients across four different clinics, achieving multiple catheter tracking at a rate of 10 images/s with a very low false positive rate of 1.06.