Automated Border Detection Research Articles

Echocardiography and Anesthesiology Successes and Challenges

Echocardiography and Anesthesiology Successes and Challenges

Assessment of cardiovascular dynamics by pressure-area relations in pediatric patients with congenital heart disease

Objectives: It is particularly useful to separately quantify the ventricular contractility and loading conditions for a better understanding of the cardiovascular dynamics in congenital heart disease, where abnormalities in chamber and loading properties may coexist. Furthermore, ventricular contractility and loading conditions may alter independently or simultaneously with disease progression and therapeutic intervention. The objectives of the present study were (1) to test whether ventricular pressure-area analysis can provide such quantitation among patients with various forms of congenital heart disease, (2) to reveal basal cardiovascular interaction in congenital heart disease by means of pressure-area analysis, and (3) to test the feasibility of this method in a simplified and less invasive form to further enhance its clinical value. Methods: We constructed pressure-area loops during caval occlusion by using transthoracic echocardiographic automated border detection combined with ventricular pressure recordings in 59 pediatric patients with congenital heart disease and in 7 normal control subjects. Results: Area measurements obtained by automated border detection were highly reproducible, and area changes reflected volume changes. The pressure-area data provided load-independent measures of contractility, which were consistently increased by use of dobutamine ( P < .05). End-systolic and arterial elastance individually quantified simultaneous changes in ventricular contractility and loading with milrinone infusion and predicted net cardiac performance. The pressure-area analysis better characterized the ventricular contractile states under a variety of loading conditions in congenital heart disease, whereas predominant load dependence of conventional indices confounded them. Furthermore, pressure-area relations were reasonably estimated from a single beat and from aortic pressure data during abdominal compression. Conclusions: Pressure-area analysis should provide a useful modality with which to assess cardiovascular dynamics in pediatric patients with congenital heart disease in more detail and should thus help improve the management of patients with this disease.

Left ventricular dysfunction after long-term right ventricular apical pacing in the young

OBJECTIVESThe goal of this study was to assess long-term global left ventricular (LV) function in patients paced from the right ventricular (RV) apex at a young age.BACKGROUNDVentricular contraction asynchrony with short-term RV apical pacing has been associated with reduced LV pump function and relaxation. The long-term effect of RV apical pacing on global LV function in the young remains unknown.METHODSTwenty-four patients with normal segmental anatomy paced from the RV apex (follow-up 1 to 19 years) underwent noninvasive assessment of global LV function with automated border detection echocardiography-derived fractional area of change (FAC), coupled with the Doppler index of myocardial performance (MPI). Data were analyzed from 24 RV-paced patients (mean follow-up 9.5 years, age 19 years, body surface area [BSA] 1.6 m2, QRS duration 140 ms) and compared with 33 age- and BSA-matched control subjects (age 16.4 years, BSA 1.6 m2). Multiple linear regression analysis was performed to identify patient variables that can affect these indexes of LV function.RESULTSAssessment of LV function (median follow-up 10 years) in 24 paced patients demonstrated impaired area- and Doppler flow-derived indexes of LV systolic and diastolic function, compared with those indexes of control subjects (FAC: 52% vs. 60%, p < 0.01; MPI: 0.46 vs. 0.34, p < 0.01). Paced QRS interval and age were found to significantly influence global LV contraction in these patients (R2= 0.4, p < 0.05).CONCLUSIONSIn the presence of impaired LV function with long-term RV apical pacing, alternative sites of ventricular pacing that simulate normal biventricular electrical activation should be explored to preserve function in pediatric patients in need of long-term pacing.

Electroconvulsive therapy impairs systolic performance of the left ventricle.

In this observational study, we examined left ventricular systolic performance during electroconvulsive therapy (ECT), using an echocardiographic automated border detection system. Nine ASA I or II patients scheduled for ECT were studied. Bilateral ECT was performed after the administration of propofol 1 mg x kg(-1), succinylcholine 1 mg x kg(-1), and assisted mask ventilation with 100% oxygen. Cardiac function was monitored by transthoracic echocardiography, prior to anesthesia induction and throughout the ECT procedure until ten minutes after the seizure. Increased end-systolic area and decreased fractional area change were observed at one minute after the seizure compared to the awake condition. No regional wall motion abnormalities were observed in all patients both at baseline condition and during the ECT CONCLUSION: Systolic performance of the left ventricle estimated by echocardiography decreased transiently in the immediate period after the electric shock.

Automated stent border detection in three-dimensional intravascular ultrasound: Improvements towards automated border detection Jouke Dijkstra, Gerhard Koning, Joan C. Tuinenburg, Pranobe V. Oemrawsingh, Johan H. C. Reiber. Leiden University Medical Center, Leiden, The Netherlands

Automated stent border detection in three-dimensional intravascular ultrasound: Improvements towards automated border detection Jouke Dijkstra, Gerhard Koning, Joan C. Tuinenburg, Pranobe V. Oemrawsingh, Johan H. C. Reiber. Leiden University Medical Center, Leiden, The Netherlands

Comparison of automated border detection for contrast ventriculograms versus human interobserver variability Florence H. Sheehan, Lei Sui, Robert M. Haralick. University of Washington, Seattle, WA

Comparison of automated border detection for contrast ventriculograms versus human interobserver variability Florence H. Sheehan, Lei Sui, Robert M. Haralick. University of Washington, Seattle, WA

Wavelet-based enhancement for detection of left ventricular myocardial boundaries in magnetic resonance images

MRI is noninvasive and generates clear images, giving it great potential as a diagnostic instrument. However, current methods of image analysis are too time-consuming for dynamic systems such as the cardiovascular system. Since dynamic imagery generate a huge number of images, a computer aided machine vision diagnostic tool is essential for implementing MRI-based measurement. In this paper, a wavelet-based image technique is applied to enhance left ventricular endocardial and epicardial profiles as the preprocessor for a dynamic programming-based automatic border detection algorithm. Statistical tests are conducted to verify the performance of the enhancement technique by comparing borders manually drawn with 1. borders generated from the enhanced images, and 2. borders generated for the original images.

Left ventricular function in hypertension and athlete’s heart: evaluation by ultrasonic automatic border detection

Left ventricular function in hypertension and athlete’s heart: evaluation by ultrasonic automatic border detection

Assessment of Right Ventricular and Right Atrial Systolic and Diastolic Performance Using Automated Border Detection.

Noninvasive assessment of right ventricular (RV) function is important clinically, but current techniques have limitations. Acoustic quantification (AQ) is an automated endocardial border detection technique that allows continuous determination of RV and right atrial (RA) area waveforms and may be useful for the assessment of RA and RV systolic and diastolic performance. Fifty patients (10 normal, 40 with RV pathology) were studied. Signal-averaged RA and RV AQ area waveforms were obtained and analyzed to compute parameters of diastolic and systolic function. All groups demonstrated significant diastolic dysfunction on the RA AQ waveform as manifested by a reduced percentage of passive atrial emptying and increased dependence on active atrial emptying. Abnormalities of diastolic performance were noted in all subgroups on RV AQ analysis as evidenced by a reduction in the percentage of ventricular filling occurring during early diastole and an increased contribution from active atrial contraction. This study demonstrates the feasibility of using automated analysis of signal-averaged RA and RV area waveforms for the evaluation of RV systolic and diastolic performance. This technique identified significant systolic and diastolic dysfunction in four groups of commonly seen right heart pathologies including biventricular heart failure, pulmonary hypertension, pressure and volume overloaded RVs, and biventricular hypertrophy.

Dobutamine stress echocardiography with automated border detection and color kinesis identifies improved diastolic left ventricular function and viable myocardium in ischemic cardiomyopathy

Since the effects of dobutamine on left ventricular systolic and diastolic function are related to the presence of myocardial viability, we attempted to establish if improvement of diastolic wail motion abnormalities assessed with automated border detection (ABD) and color kinesis (CK) has an adjunctive value in detecting hibernating but viable myocardium. 21 patients (pts) with ischemic cardiomyopathy (left ventricular ejection fraction -LVEF-: 0.31-+0.11) were studied with low dose (5-10 mcg/Kg/min) dobutamine stress echocardiography (DSE). ABD waveforms of LV area change and the rate of area change were displayed along with the electrocardiogram and the concurrent cross sectional image. CK digitized LV end-systolic and end-diastolic images were evaluated by reviewing the stored loops obtained in all pts. Endocardial tracking was considered adequate when the visually assessed systolic excursion matched the colorencoded images. Viability was defined as akinetic or hypokinetic segments becoming normokinetic with systolic wall thickening. At baseline and during peak infusion LVEF, peak ejection rate (PER: ml]s), peak filling rate (PFR: ml/s) and mean time of diastolic endocardial motion (tDEM: ms) were calculated. In 10 pts viability was present (group 1), in 11 pts viability was absent (group 2). In group 1 pts there was a significantly increase from baseline to peak infusion in LVEF (0.28-+0.11 vs 0.42_+0.8, p<0.005), PER (1.64-+0.61 vs 2.98--0.97, p<0.005), PFR (1.52--0.53 vs 2.69+0.92, p<0.005) and significant decrease in mean tDEM (304_+41 vs 205--23, p<0.001). In group 2 pts a significantly increase was shown in LVEF (0.27-+0.9 vs 0.38+0.10, p<0.05) and PER (1.41 -+0.72 vs 2.I 1-+0.83, p<0.05); no significant difference was found in PFR (1.39-+0.61 vs 1.74_+0.73, p=NS) and tDEM (315_+39 vs 304_+31, p=NS). Thus, ABD and CK parameters of diastolic function (PFR, tDEM) improved only in pts with hibernating but viable myocardium whereas global systolic function can improve in the presence of both viability and non viability.

Left atrial relaxation and left ventricular systolic function determine left atrial reservoir function.

Determinants of left atrial (LA) reservoir function and its influence on left ventricular (LV) function have not been quantified. In an open-pericardium, paced (70 and 90 bpm) pig model of LV regional ischemia (left anterior descending coronary constriction), with high-fidelity LV, LA, and RV pressure recordings, we obtained the LA area with 2D automated border detection echocardiography, LA pressure-area loops, and Doppler transmitral flow. We calculated LV tau, LA relaxation (a-x pressure difference divided by time, normalized by a pressure), and stiffness (slope between x and v pressure points of v loop). Determinants of total LA reservoir (maximum-minimum area, cm(2)) were identified by multiple regression analysis. Different mean rates of LA area increase identified 2 consecutive (early rapid and late slow) reservoir phases. During ischemia, LV long-axis shortening (LAS, LV base systolic descent) and LA reservoir area change decreased (7.3+/-0.3 [SEM] versus 5.6+/-0.3 cm(2), P<0.001) and LA stiffness increased (1.6+/-0.3 versus 3.1+/-0.3 mm Hg/cm(2), P=0.009). Early reservoir area change depended on LA mean ejection rate (LA area at ECG P wave minus minimum area divided by time; multiple regression coefficient=0.9; P<0.001) and relaxation (coefficient=4.9 cm(2)xms/s; P<0.001). Late reservoir area change depended on LAS (coefficient=8 cm/s; P<0.001). Total reservoir filling depended on LA stiffness (coefficient=-0.31 cm(4)/mm Hg; P=0. 001) and cardiac output (coefficient=0.001 cm(2)xmin/L; P=0.002). The strongest predictor of cardiac output was LA reservoir filling (coefficient=301 L/minxcm(2); P<0.001). The v loop area was determined by cardiac output, LV ejection time, tau, and early transmitral flow. Two (early and late) reservoir phases are determined by LA contraction and relaxation and LV base descent. Acute LV regional ischemia increases LA stiffness and impairs LA reservoir function by reducing LV base descent.

Impact of On-Line Endocardial Border Detection on Determination of Left Ventricular Volume and Ejection Fraction by Transthoracic 3-Dimensional Echocardiography

This study was performed to determine whether use of on-line automated border detection (ABD) could reduce data analysis time for 3-dimensional echocardiography (3DE) while maintaining accuracy of 3DE in measures of left ventricular (LV) volumes and ejection fraction (EF). The study proceeded in 2 phases. In the validation phase, 20 subjects were examined with the use of 3DE and of monoplane 2-dimensional (2D) ABD. Results were compared with the reference standard of magnetic resonance imaging (MRI). In the test phase, 20 subjects underwent two 3DE studies (once with images optimized for visual border definition and once with images optimized for ABD border tracking) and a conventionally used 2D ABD study. For 3DE, volumes and EF were determined with the use of manually traced borders and ABD. Analysis times were recorded with a digital stopwatch. In the validation phase, 3DE and MRI results correlated very well ( r = 0.99) without systematic differences. Comparison of 2D ABD with MRI showed good correlation for LV volumes ( r ≥ 0.90) and EF ( r = 0.85) despite significant underestimation. For the test phase, Acoustic Quantification–optimized 3-dimensional datasets underestimated end-diastolic volume and EF relative to visually optimized 3-dimensional datasets regardless of whether borders were hand-traced or ABD was used. However, correlations ranged from r = 0.96 to r = 0.98 for LV volumes and 0.88 to 0.91 for LV EF and were superior to those for 2D ABD. Data analysis times decreased moderately with the use of ABD, but scan times increased; total study times were unchanged. Use of on-line ABD with 3DE reduces data analysis time and is more accurate than conventional monoplane 2D ABD but results in underestimation of LV volumes and EF. Additional automated postprocessing techniques may be required to obtain accurate measures, consistently using 3DE in conjunction with on-line ABD. (J Am Soc Echocardiogr 1999;12:551-8.)

Recovery of LV contractility in man is enhanced by preischemic administration of enflurane

Background. Volatile anesthetics enhance postischemic functional recovery in animal models; this effect has not been investigated in man.Methods. Twenty-two patients undergoing coronary surgery were randomized to enflurane administration (0.5% to 2%) for 5 minutes to reduce systolic blood pressure by 20% to 25% immediately before cardioplegic arrest. Left ventricular contractility was assessed by pressure-area relations using echocardiographic automated border detection during inflow occlusion before and after cardiopulmonary bypass. Linear regression analysis in 16 patients with paired data sets assessed changes in contractility.Results. The relation was highly linear (r = 0.95 ± 0.02). A change of slope versus the change in x intercept was detected in controls (mean difference, 16.1 mm Hg/cm2, 95% confidence limits, 5.9 to 26.3; 2.2 cm2, 95% confidence limits, −1.1 to 5.5; p = 0.007), which was different from those of treated patients (mean difference, 0.7 mm Hg/cm2, 95% confidence limits, −2.2 to 3.7; −0.06 cm2, 95% confidence limits, −1.6 to 1.5; p > 0.2). Analysis of covariance in the overall group confirmed a significant effect of treatment (p = 0.002).Conclusions. Enflurane enhances postischemic functional recovery, possibly through pharmacologic preconditioning of myocardium.

Automatic border detection identifies subclinical anthracycline cardiotoxicity in children with malignancy.

Anthracycline drugs for cancer therapy often cause functional myocardial impairment even in relatively low doses. We investigated the left ventricular function in asymptomatic anthracycline-treated children by automatic border detection (ABD) to assess its clinical usefulness for unmasking latent anthracycline-induced myocardial damage. Thirty-four children (0.7 to 17.6 years old) during or after anthracycline chemotherapy (26 to 1100 mg/m2) for malignancy (Chemo group) were studied, and 40 children (2.8 to 15.6 years old) without cardiac involvement served as normal control subjects (Control group). All patients underwent complete echocardiographic examination, including M-mode, Doppler, and ABD. Conventional echocardiography disclosed no difference between groups with regard to ejection fraction and the ratio of early to late transmitral flow velocity. In marked contrast, an investigation using ABD revealed that the Chemo group appeared to have some anthracycline-induced myocardial damage. In the apical 4-chamber view, peak filling rate in the Chemo group [2.3+/-0.4 end-diastolic area (EDA)/s] was significantly lower than that in the Control group (3.1+/-0.5 EDA/s) (P<0.0001), and time to peak filling rate in the Chemo group (106+/-31 ms) was clearly prolonged compared with that in the Control group (74+/-22 ms) (P<0.0001). Echocardiographic ABD may be a sensitive and useful noninvasive approach for evaluating subclinical anthracycline cardiotoxicity.

Hemodynamic monitoring during left atriofemoral bypass for resection of a postductal aortic isthmus stenosis: Current role of intraoperative transesophageal echocardiography

Hemodynamic monitoring during left atriofemoral bypass for resection of a postductal aortic isthmus stenosis: Current role of intraoperative transesophageal echocardiography

Evaluation of Global and Regional Right Ventricular Function Using Automated Border Detection Techniques.

Quantitative evaluation of right ventricular (RV) function remains challenging due to the complex geometry of this chamber, which precludes the use of simple geometric assumptions. Automated border detection (ABD) techniques, which provide online changes in cardiac chamber dimensions, have been predominantly used for quantitative assessment of global as well as regional left ventricular function. Recently, acoustic quantification has been validated for quantitative evaluation of global RV function, and color kinesis has been used to objectively assess systolic and diastolic regional RV function. In this article, the main studies validating ABD for the objective assessment of global RV function and the current clinical uses of this technique are reviewed. In addition, technical guidelines and limitations of ABD techniques are described, and potential applications of color kinesis for quantitative assessment of regional systolic and diastolic RV performance are detailed. ABD techniques provide new insights into right atrial and RV systolic and diastolic properties. The clinical value of these techniques in the diagnosis, prognosis, and potential guidance of therapeutic management of RV dysfunction remains to be determined.

Use of transesophageal echocardiography for postoperative evaluation of right ventricular function

Background. No method has been available to assess the right ventricular (RV) pressure–volume relation in the operating room or intensive care unit. Left ventricular cross-sectional area measured by echocardiography using the technology of automated border detection has been used to construct left ventricular pressure–area (P-A) loops. In the human right ventricle, however, this approach has not been validated. Methods. We recorded RV P-A loops in 14 patients in the intensive care unit using transesophageal echocardiography. Multiple RV P-A loops were obtained by reducing preload with intravenous nitroglycerin, thereby elucidating the end-systolic P-A relation. Results. With an incremental dose of dobutamine, the slope of the RV end-systolic P-A relation increased (from 4.56 ± 2.42 to 7.34 ± 3.62 mm Hg/cm 2, p < 0.01), with no change in the x-axis intercept, which implied increased contractility. Furthermore, in the operating room we validated the use of RV cross-sectional area as a surrogate for RV volume by demonstrating the close correlation between the stroke area (maximal RV area minus minimal RV area) and stroke volume ( r = 0.962; p < 0.0001). Conclusions. Tranesophageal echocardiography with automated border detection is a promising tool for elucidating RV function through the analysis of RV P-A loops.

Load-Independent Indices of Left Ventricular Function Using Automated Border Detection.

Echocardiographic automated border detection is the ability to assess left ventricular (LV) cross-sectional cavity areas and volumes on line. This capability has enabled the use of LV pressure-volume relationships as a means to determine LV function in a manner relatively independent of loading conditions. This discussion reviews previous validation studies in animal models and humans using LV cross-sectional area as a surrogate for LV volume and the clinical applications of LV pressure-area relations. Applications of arterial pressure as a substitute for LV ejection pressure to assess pressure-area relations are also reviewed, along with the use of pressure-area relations to assess right ventricular performance. Last, preload-adjusted maximal power as an alternative load-insensitive means to determine LV performance is discussed.

Effects of Partial Left Ventriculectomy on Cardiac Performance

To the Editor: We read with great interest the recent article by Gorcsan et al.1 They report heterogeneous immediate effects of partial left ventriculectomy (PLV) on the slope (Ees) of end-systolic pressure-area relations obtained with echocardiographic automated border detection in 8 patients. The average change in Ees was from 6.5±3.4 mm Hg/cm2 (before PLV) to 4.3±2.5 mm Hg/cm2 (immediately after PLV) ( P =NS). The authors, however, overlooked an error made by the iterative linear regression technique that they used to calculate Ees. In the right bottom panel of the Figure, where the decreased Ees (1.1 mm Hg/cm2) was demonstrated after PLV, the end-systolic pressure-area …

Automatic Border Detection for Assessment of Left Ventricular Diastolic Function Among Normal Neonates: Comparison with Doppler Echocardiography.

Doppler echocardiography is the standard noninvasive method to assess left ventricular (LV) diastolic function. Recently, automatic border detection (ABD), a method based on analysis of integrated ultrasonic backscatter, has been introduced permitting real-time, on-line assessment of LV diastolic function. A comparison of these methods in normal, full-term neonates has not been performed. Therefore, the objectives of this study were to evaluate the usefulness of ABD in the assessment of LV diastolic function among normal neonates, to compare parameters obtained with the ABD method with standard Doppler-derived indexes of diastolic function, and to assess the reproducibility of ABD measurements. We studied 17 consecutive normal neonates during natural sleep with both methods shortly after birth (mean 17.4 +/- 3.9 h) and approximately 2 weeks later (mean 14.8 +/- 2.2 days). An average of five consecutive cardiac cycles were performed. Similar to Doppler indexes, no significant change in any ABD parameter of diastolic function occurred between the early and later studies. A complete ABD study could be performed within 5 minutes. Mean interobserver variation for individual ABD measurements ranged from 0% to 11%. Compared with Doppler, rapid filling fraction was greater and atrial filling fraction was less with ABD. Regression analysis showed poor correlation of these parameters between methods, but their ratio by each method remained constant between studies. A similar poor correlation existed between peak E wave velocity by Doppler and peak rapid filling rate by ABD and between peak A wave velocity by Doppler and peak atrial filling rate by ABD. These differences may be explained by technical factors and different aspects of diastolic filling assessed by each method. This study indicated that ABD was a feasible and reproducible method compared with Doppler echocardiography for serial evaluation of LV diastolic function among neonates.