Left ventricular (LV) volumes obtained from RT3DEdatasets are underestimated compared to cardiac magnetic resonance (CMR). We sought to study the accuracy and reproducibility of this technique in a multicenter setting, the inter-institutional differences in these variables in relationship with investigators' experience, and the potential sources of underestimation. 92 patients underwent CMR and RT3DE imaging at 4 different institutions. ESV: r=0.93), but were 29 and 26% lower. This finding was consistent across participating institutions, with the magnitude of bias being related to experience. Exclusion of trabeculae and mitral valve plane from the CMR reference essentially eliminated the inter-modality bias. In conclusion, LV volumes are underestimated in most patients because RT3DE imaging cannot differentiate between the myocardium and trabeculae. IntroductionThe superiority of 3D measurements of LV volume measurements based on endocardial surface detection [1,2] was recently demonstrated for RT3DE imaging in terms of improved accuracy [3,4] and reproducibility of [2,4]. Although this methodology has been compared against CMR in single center studies, it has not been validated in a standardized protocol in a multicenter setting. Importantly, several recent studies have reported that RT3DE underestimates LV volumes [2,5] to a variable extent, but no consensus has been reached regarding the factors contributing towards this error. We hypothesized that this underestimation may be due to differences in spatial and contrast resolution between RT3DE and CMR imaging that determine the level of detail with which the LV endocardial surface is visualized. Also, the inter-modality discordance may be increased by analysis related differences.This study was designed to: (1) validate volumetric analysis of the left ventricle from RT3DE datasets against the standard CMR reference technique in a multicenter setting, (2) compare the reproducibility of this analysis with CMR measurements, (3) study inter-institutional differences in accuracy and reproducibility of the RT3DE volume measurements in relationship with the level of the investigators' experience, and (4) to identify and evaluate the relative contributions of the potential sources of error. Methods Study designInitially, aim 1, i.e. the accuracy of RT3DE volume measurements, was addressed by analyzing RT3DE and CMR images obtained in a large group of patients and comparing ESV and EDV between the two modalities. Aim 2, i.e. the reproducibility of both techniques, was achieved using repeated measurements.To achieve aim 3, i.e. the experience-related interinstitutional differences, investigators in the participating institutions, were given different levels of instruction and training with the prototype software (QLAB, 3DQ-Advanced, Philips). The investigators were not informed that the level of experience was part of the study design. Accuracy and reproducibility were compared between institutions and correlated with the level of experience.To achieve aim 4, i.e. iden...
Three-dimensional echocardiography (3DE) provides volumetric measurements without geometric assumptions. Volume-rendered 3DE has been shown to be accurate for the measurement of right ventricular (RV) volumes in vitro and in animal studies; however, few data are available regarding its accuracy in patients. This study examined the accuracy of 3DE for quantitation of RV volumes and ejection fraction (EF) in patients, compared to magnetic resonance imaging (MRI) and radionuclide ventriculography (RNV). Twenty patients underwent MRI, gated equilibrium RNV, and 3DE using rotational acquisition from both the transesophageal and transthoracic approaches. RV volumes and EF were calculated from the 3DE data using multislice analysis (true Simpson's rule). RV volumes calculated by MRI (end-diastolic volume (EDV) 109.4 +/- 34.3 mls, end-systolic volume (ESV) 59.6 +/- 31.0 mls, and EF 47.7 +/- 17.1%) agreed closely with 3DE. For transesophageal echocardiography, EDV was 108.1 +/- 29.7 mls (r = 0.86, mean difference 1.3 +/- 17.8 mls); ESV was 62.5 +/- 23.8 mls (r = 0.85, mean difference 2.8 +/- 15.1 mls); and EF was 43.2 +/- 11.7% (r = 0.84, mean difference 4.5 +/- 9.7%). For transthoracic echocardiography, EDV was 107.7 +/- 27.5 mls (r = 0.85, mean difference 1.6 +/- 18.2 mls); ESV was 59.7 +/- 22.1 mls (r = 0.93, mean difference 3.2 +/- 19.6 mls); and EF was 45.2 +/- 11.5% (r = 0.86, mean difference 2.0 +/- 9.4%). There were close correlations, small mean differences and narrow limits of agreement between RNV-derived EF (43.4 +/- 12.1%) and both transesophageal (r = 0.95 mean difference 0.2 +/- 3.7%) and transthoracic 3DE (r = 0.95, mean difference 1.8 +/- 5.4%). Three-dimensional echocardiography is a promising new method of calculating RV volumes and EF, comparing well with MRI and RNV. The accuracy of transthoracic 3DE was comparable to that of the transesophageal approach. Three-dimensional echocardiography has the potential to be useful in the clinical assessment of RV disorders.
ࡗ ࡗPurpose: To present initial experience with emergent stent-graft placement for impending rupture of the descending thoracic aorta. Case Reports: Intramural hematoma (IMH) of the descending thoracic aorta was diagnosed by transesophageal echocardiography and computed tomography in 3 patients with acute onset of severe thoracic pain. Because of signs of impending rupture, e.g., pleural effusion, sustained pain, or transadventitial bleeding, the patients underwent emergency stent-graft placement, which was successful in all cases. No procedure-related complications were observed. Follow-up to 18 months has revealed no evidence of endoleak, and all patients remain free of symptoms. Conclusions: Emergency stent-graft placement may be a promising alternative to conventional surgery in patients with impending aortic rupture due to IMH. J Endovasc Ther 2002;9:II-72-II-78
Ultrasound can be exploited to derive therapeutic results by using its bioeffects such as creation of mechanical vibrations, localized cavitations, microstream formation, physicochemical changes and thermal energy. Extensive in vitro and animal investigations during the last 2 decades have laid a foundation for ultrasound energy to be used for treatment purposes in various medical specialties. In the area of cardiovascular diseases, ultrasound could be used for thrombolysis, adjunct to coronary interventions, drug delivery, local gene transfer, and creating therapeutic lesions. The dispensation approaches to therapeutic ultrasound are varied, from the use of low- to medium-range frequency, low to focused high intensity, and catheter-based to external devices. Catheter-based ultrasound could be useful for intracoronary thrombolysis, and external ultrasound instrument with transcutaneous delivery could be of use in applications such as creation of myocardial lesions, peripheral vessel thrombolysis, and drug and gene delivery. Adjunct administration of microbubbles has been found to enhance thrombolysis, and drug and gene therapy. Ongoing studies strongly suggest that therapeutic ultrasound could have an important role in cardiovascular disorders associated with thrombosis, inflammation, atherosclerotic disease, and arrhythmias.
Evaluating valvular heart disease requires a multi-parametric analysis of valvular pathology, hemodynamic derangements, and impact on ventricular size and function. The capability to perform real-time three-dimensional (3-D) imaging has vastly strengthened the already established role of echocardiography. CT and MRI advances have led to their use as daily clinical tools. Two-dimensional and 3-D echocardiography and Doppler modalities allow for accurate assessment of valvular lesions, pressure gradients, stenotic valve orifice areas, pulmonary artery pressures, intracardiac pressures, and regurgitant volumes. Quantitation of chamber volumes has become more accurate and reproducible with 3-D echocardiography, CT, and cardiac MRI. Although ultrasound imaging is the primary tool, the other techniques provide adjuvant or alternate options to examine valvular heart disease. This array of imaging modalities is likely to provide greater insights into the pathophysiology of valvular heart disease, new pointers to prognosis, and also guide innovative treatment strategies.
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