Importance of transducer displacement and tilting on three-dimensional echocardiographic volume assessment using apical or off-axis rotational acquisition: an in vitro study

Left ventricular apical aneurysm in chronic Chagas cardiomyopathy-A case report

A 56-year-old female, who immigrated to the USA from Honduras, presented with worsening shortness of breath, orthopnea, paroxysmal nocturnal dyspnea, and decreased exercise tolerance over the previous 2 months. She was diagnosed 1 year previously with non-ischemic dilated cardiomyopathy and non-sustained monomorphic ventricular tachycardia. An implantable cardioverter defibrillator was placed. Cause for her dilated cardiomyopathy was unknown at that time. On admission, her electrocardiogram showed low voltage complexes, with frequent premature ventricular contractions. Transthoracic two-dimensional echocardiogram (2D ECHO) showed severely reduced ejection fraction of 20%, severe mitral regurgitation with left ventricular (LV) hypokinesis, and inferolateral and inferior wall akinesis. On review of her records, a contrast 2D ECHO from the previous year revealed an aneurysm of the LV apical region. Live three-dimensional (3D) ECHO on her present admission showed persistent LV apical aneurysm. Computed tomography angiogram showed no atherosclerotic lesions. Multiple episodes of non-sustained ventricular tachycardia were recorded on telemetry. Based on these findings, the diagnosis of Chagas cardiomyopathy was entertained. Serological tests for Trypanosoma cruzi antibodies were done and returned positive. We report a case of chronic Chagas cardiomyopathy that was initially missed but ultimately diagnosed based on the finding of LV apical aneurysm. <Learning objective: Chagas cardiomyopathy is becoming increasingly prevalent in non-endemic countries. One hallmark finding associated with Chagas cardiomyopathy is left ventricle apical aneurysm. We were able to identify this finding with transthoracic contrast 2D ECHO and live 3D ECHO.>.

Validation of a volumic reconstruction in 4-d echocardiography and gated SPECT using a dynamic cardiac phantom

A dynamic cardiac phantom was used as a reference to compare the volumes reconstructed with 4-D echocardiography and gated single-photon emission computed tomography (SPECT). 4-D echocardiography used a new prototype of rotating scan head to acquire ultrasound (US) images during a cardiac cycle, associated with a new protocol (left ventricular 4-D or LV 4-D) to reconstruct the volume deformations of the heart as a function of time. Gated SPECT data were acquired with a standard single-head gamma camera, and the reconstructions were carried out using the Mirage software released by Segami. The influences of different LV 4-D parameters were tested and analyzed. End-diastolic volume, end-systolic volume, and ejection fraction were measured using both LV 4-D and gated SPECT. Results obtained showed a straight correlation between the two examinations. The agreement confirmed the relevance of the comparisons. This study is an initial step before conducting clinical trials to exhaustively compare the two modalities.

Quantification of left ventricular volumes and ejection fraction using freehand transthoracic three-dimensional echocardiography: comparison with magnetic resonance imaging

OBJECTIVES

Our aim was to validate 3-dimensional echocardiography (3DE) for assessment of left ventricular (LV) end-diastolic volume, end-systolic volume (ESV), stroke volume, and ejection fraction (EF) using the freehand-acquisition method. Furthermore, LV volumes by breath hold-versus free breathing-3DE acquisition were assessed and compared with magnetic resonance imaging (MRI).

METHODS

From the apical position, a fan-like 3DE image was acquired during free breathing and another, thereafter, during breath hold. In 27 patients, 28 breath hold- and 24 free breathing-3DE images were acquired. A total of 17 patients underwent both MRI and 3DE. MRI contours were traced along the outer endocardial contour, including trabeculae, and along the inner endocardial contour, excluding trabeculae, from the LV volume.

RESULTS

All 28 (100%) breath hold- and 86% of free breathing-3DE acquisitions could be analyzed. Intraobserver variation (percentual bias +/- 2 SD) of end-diastolic volume, ESV, stroke volume, and EF for breath-hold 3DE was, respectively, 0.3 +/- 10.2%, 0.3 +/- 14.6%, 0.1 +/- 18.4%, and -0.1 +/- 5.8%. For free-breathing 3DE, findings were similar. A significantly better interobserver variability, however, was observed for breath-hold 3DE for ESV and EF. Comparison of breath-hold 3DE with MRI inner contour showed for end-diastolic volume, ESV, stroke volume, and EF, a percentual bias (+/- 2 SD) of, respectively, -13.5 +/- 26.9%, -17.7 +/- 47.8%, -10.6 +/- 43.6%, and -1.8 +/- 11.6%. Compared with the MRI outer contour, a significantly greater difference was observed, except for EF.

CONCLUSIONS

3DE using the freehand method is fast and highly reproducible for (serial) LV volume and EF measurement, and, hence, ideally suited for clinical decision making and trials. Breath-hold 3DE is superior to free-breathing 3DE regarding image quality and reproducibility. Compared with MRI, 3DE underestimates LV volumes, but not EF, which is mainly explained by differences in endocardial contour tracing by MRI (outer contour) and 3DE (inner contour) of the trabecularized endocardium. Underestimation is reduced when breath-hold 3DE is compared with inner contour analysis of the MRI dataset.

Partial cut-off of the left ventricle: determinants and effects on volume parameters assessed by real-time 3-D echocardiography

A total of 44 patients with coronary artery disease underwent real-time three-dimensional (3-D) echocardiography for end systolic (ES) and end diastolic (ED) left ventricular (LV) volumetric analysis to assess the effect of partial cut-off of the left ventricular (LV) apex on volumetric analysis by apical transthoracic echocardiography. Patients with LV cut-off were assigned to either group 1 (ejection fraction, (EF) < 49%) or group 2 (EF > or = 49%). Patients were additionally classified as group A if they had anterior or apical wall motion abnormalities (WMA) or group B if they had only inferoposterior or lateral WMA. Partial LV cut-offs were found in 22 subjects (50%). The estimated end diastolic cut-off volumes were as follows: 8.6 +/- 3.2 mL (group 1), 4.3 +/- 2.4 mL (group 2), 9.1 +/- 3.3 mL (group A) and 1.4 +/- 0.8 mL (group B). In group 1, more patients with LV volume cut-off were found than in group 2: chi(2) = 4.52, p < 0.05; and in group A more than in group B: chi(2) = 8.08, p < 0.01. In all, partial LV cut-off led to underestimation of LV volumes: 5.9 +/- 4.7 ml (ED) vs. 2.1 +/- 1.3 ml (ES), p <0.02. In conclusion, LV cut-offs can potentially alter the accuracy of echocardiographic volumetric analysis, particularly in anterior or apical WMA.

Volume quantification of intracardiac mass lesions by transesophageal three-dimensional echocardiography

As compared with two-dimensional (2-D) transesophageal echocardiography (TEE), 3-D echocardiography now permits more realistic visualization of cardiac anatomy and of intracardiac lesions. The aim of this study was to apply newer 3-D echocardiographic techniques to quantify volumes of intracardiac masses undergoing surgical resection seen during an intraoperative TEE. The calculated volumes were compared with actual in vitro measurements of surgically resected masses. A total of 14 patients (9 men; 5 women; age range between 21 and 77 years) with intracardiac mass lesions (4 tumors: 3 left atrial myxomas and 1 mitral valve fibroelastoma, and 10 vegetations: 5 aortic valve, 3 mitral valve, 1 tricuspid and 1 pulmonary valve) were studied. Using commercially available 3-D reconstruction software (TomTec v. 4.1), the volumes of intracardiac masses were estimated using both the average rotation (rotation around the long axis, AR) and disk summation (parallel short axis cuts, DS) methods. Volumes of these lesions were also measured in vitro by water submersion. They ranged from 0.20 mL to 24 mL (mean +/- SD = 8.07 +/- 9.21 mL). Both 3-D TEE AR and 3-D TEE DS calculated volumes correlated excellently with in vitro measured volumes (r = 1.00 and r = 0.98, respectively, p = < 0.0001). The correlation between 3-D TEE AR and 3-D TEE DS calculated volumes was also excellent (r = 0.98, p = < 0.0001). In conclusion, the volume assessments by 3-D TEE of intracardiac mass lesions correlated well with in vitro measured volumes of surgical specimens. This technique may prove to be valuable in further defining intracardiac pathology and is a further advancement toward the application of clinically useful 3-D echocardiography.