Calculation Of Ventricular Volume Research Articles

Left ventricular stroke volume calculation based on Reuleaux triangle formula: correct geometric characteristics of aortic root in systemic blood flow assessment

Left ventricular stroke volume calculation based on Reuleaux triangle formula: correct geometric characteristics of aortic root in systemic blood flow assessment

IMG-22. A DEEP LEARNING MODEL FOR AUTOMATIC POSTERIOR FOSSA PEDIATRIC BRAIN TUMOR SEGMENTATION: A MULTI-INSTITUTIONAL STUDY

BACKGROUNDBrain tumors are the most common solid malignancies in childhood, many of which develop in the posterior fossa (PF). Manual tumor measurements are frequently required to optimize registration into surgical navigation systems or for surveillance of nonresectable tumors after therapy. With recent advances in artificial intelligence (AI), automated MRI-based tumor segmentation is now feasible without requiring manual measurements. Our goal was to create a deep learning model for automated PF tumor segmentation that can register into navigation systems and provide volume output.METHODS720 pre-surgical MRI scans from five pediatric centers were divided into training, validation, and testing datasets. The study cohort comprised of four PF tumor types: medulloblastoma, diffuse midline glioma, ependymoma, and brainstem or cerebellar pilocytic astrocytoma. Manual segmentation of the tumors by an attending neuroradiologist served as “ground truth” labels for model training and evaluation. We used 2D Unet, an encoder-decoder convolutional neural network architecture, with a pre-trained ResNet50 encoder. We assessed ventricle segmentation accuracy on a held-out test set using Dice similarity coefficient (0–1) and compared ventricular volume calculation between manual and model-derived segmentations using linear regression.RESULTSCompared to the ground truth expert human segmentation, overall Dice score for model performance accuracy was 0.83 for automatic delineation of the 4 tumor types.CONCLUSIONSIn this multi-institutional study, we present a deep learning algorithm that automatically delineates PF tumors and outputs volumetric information. Our results demonstrate applied AI that is clinically applicable, potentially augmenting radiologists, neuro-oncologists, and neurosurgeons for tumor evaluation, surveillance, and surgical planning.

Left Ventricular End Diastolic Volume and Ejection Fraction Calculation: Correlation between Three Echocardiographic Methods.

Background Left ventricular ejection fraction (LVEF) and end diastolic volume (EDV) are measured using Simpson's biplane (SB), 3-dimensional method (3DE), and speckle tracking (STE). Comparisons between methods in routine practice are limited. Our purpose was to compare and to determine the correlations between these three methods in clinical setting. Methods LVEF and EDV were measured by three methods in 474 consecutive patients and compared using multiple Bland–Altman (BA) plots. The correlations (R) between methods were calculated. Results Median (IQR) LVEF_SB, LVEF_STE, and LVEF_3DE were 63.0% (60–69)%, 61% (57–65)%, and 62% (57–68)%. Median (IQR) EDV_SB, EDV_STE, and EDV_3DE were 85 ml (71–106) ml, 82 ml (69–100) ml, and 73 ml (59–89) ml. R between LVEF_SB and LVEF_3DE was 0.65 when echogenicity was good and 0.43 when poor. R for EDV_SB and EDV_3DE was 0.75 when echogenicity was good and 0.45 when poor. On BA analysis, biases were acceptable (<3.5% for LVEF) but limits of agreement (LOA) were large: 95% of the differences were between −15.4% and +18.8% for LVEF as evaluated by SB in comparison with 3DE, with a bias of 1.7%. In the comparison EDV_SB and EDV_3DE, the bias was 14 ml and the LOA were between −24 ml and +53 ml. On linear regressions, LVEF_3DE = 17.92 + 0.69 LVEF_SB and EDV_3DE = 18.94 + 0.63 EDV_SB. Conclusions The three methods were feasible and led to acceptable bias but large LOA. Although these methods are not interchangeable, our results allow 3DE value prediction from SB, the most commonly used method.

Automatic calculation of left ventricular volume in magnetic resonance imaging using an image-based clustering approach

In this work we propose an algorithm to automate the process of left ventricular (LV) volume calculation during magnetic resonance imaging (MRI) analysis. The proposed algorithm does the LV segmentation, volume calculation, finds the time frames where the heart is in systole and diastole phase, and calculates LV ejection fraction. The proposed approach has been tested on a dataset containing MRI study results of 500 patients. According to experimental results the root mean square error of LV systolic volume calculation is 21.64 ml, LV diastolic volume - 44.92 ml, ejection fraction - 7.96 %.

Comparison of single-plane and biplane area-length methods for right ventricular volume calculation: In vivo and vitro study

Currently, both single-plane and biplane area-length methods by two-dimensional echocardiography were commonly used for calculating RV volume in clinical practice, however, little is known regarding the correlation between the two modalities. We try to assess the accuracy of ventricular volume measurement of single-plane and biplane area-length methods by both in-vitro and in-vivo studies.

Calculation of right ventricular stroke volume in short-axis MR images using the equation of the tricuspid plane

Short-axis (SA) magnetic resonance (MR) images are commonly planned parallel to the left atrioventricular valve. This orientation leads to oblique slices of the right ventricle (RV) with subsequent difficulties in separating the RV from the right atrium in the SA images. The insertion points of the tricuspid valve (TV) in the myocardium can be clearly identified in the right ventricle long axis (RVLA) and four-chamber (4CH) views. The purpose of this study was to develop a method that transfers the position of the tricuspid plane, as seen in the RVLA and 4CH views, to the SA images to facilitate the separation of the RV from the atrium. This methodology, termed Dissociating the Right Atrium from the Ventricle Volume (DRAW), was applied in 20 patients for calculations of right ventricular stroke volume (RVSV). The RVSV using DRAW (RVSV(DRAW)) was compared to left ventricular stroke volumes (LVSV) obtained from flow measurements in the ascending aorta. The RVSV was also determined using the conventional method (RVSV(CONV)) where the stack of images from the SA views are summarized, and a visual decision is made of the most basal slice to be included in the RV. The mean difference between RVSV(DRAW) and LVSV was 0·1 ± 12·7 ml, while the mean difference between RVSV(CONV) and LVSV was 0·33 ± 14·3 ml. Both the intra- and interobserver variability were small using the DRAW methodology, 0·6 ± 3·5 and 1·7 ± 2·7 ml, respectively. In conclusion, the DRAW method can be used to facilitate the separation of the RV and the atrium.

Assessment of Left Ventricular Volumes and Function by Real Time Three‐Dimensional Echocardiography in a Pediatric Population: A TomTec versus QLAB Comparison

Three-dimensional echocardiography (3DE) allows accurate calculation of ventricular volumes despite a remaining geometric assumption on the ventricular shape. Few studies involving full volume reconstruction software have been performed on children. Our aim was to compare the left ventricular (LV) volume measurements obtained with the most used 3D analysis software in a pediatric population. Fifty patients (median age: 9.5 years) without cardiac disease were included in the study. 3DE was performed with the X4-2 or X7-2 matrix probe (ie33, Philips). The LV volume analysis was performed with QLAB 6.0 (semiautomated border detection) and TomTec 4D LV (primary manual tracking with semiautomated border detection). TomTec analysis feasibility amounted to 94% whereas QLAB analysis feasibility only reached 80% (P = 0.037). The analysis time was shorter with QLAB than TomTec (5 ± 2 versus 6 ± 3 minutes, P < 0.05). The stroke volume, end diastolic and end systolic LV volume measurements performed on the 40 patients were strongly correlated (r > 0.97; P < 0.0001) with minimal bias. The LV ejection fraction was well correlated (r = 0.79; P < 0.0001). 3D LV volume quantification is feasible either by using manual or automated reconstruction software in a normal pediatric population. LV Measurements are well correlated. Differences in volume reconstruction algorithms provide specific software performance characteristics. TomTec is a more feasible method but requires a longer analysis time. Further studies are needed to validate the accuracy of the method to calculate enlarged LV volumes in patients with congenital heart diseases.

Real Time Triplane Echocardiography in Aortic Valve Stenosis: Validation, Reliability, and Feasibility of a New Method for Valve Area Quantification

The aim of the study was to validate a novel formula for aortic valve area (AVA) based on the principle of continuity equation, that substitutes Doppler-derived stroke volume (SV) by SV directly measured with real time simultaneous triplane three-dimensional echocardiography (RT3P). RT3P has proved accuracy for left ventricular volume calculation. So far, however, neither this potential has been applied to hemodynamic assessment, nor RT3P has succeeded in the evaluation of aortic valve disease. AVA was measured in 21 patients with aortic stenosis using Gorlin's equation, Doppler continuity equation (two-dimensional echocardiography), the novel RT3P method, and by substituting Doppler-derived SV by SV measured with two-dimensional stroke volume (2DSV). RT3P has the best linear association (R(2)= 0.61) and the best correlation with Gorlin of all noninvasive methods (even if not statistically significant). RT3P carries significantly lower mean differences with catheterization, as compared with 2D and 2DSV (Table 4). Standard deviations of mean differences between RT3P and catheterization and between the other echocardiographic methods are not statistically different, even if RT3P seems to be nearer to catheterization. Inter- and intraobserver variability were, respectively, 0.03 +/- 0.11 cm(2) and 0.02 +/- 0.03 cm(2), better than 2D and 2DSV. RT3P has revealed to be more accurate than two-dimensional method in AVA quantification, with a better intraobserver agreement. In addition, it allows simple and fast image acquisition.

The Accuracy of Echocardiographic Assessment of Left Ventricular Size in Children by the 5/6 Area × Length (Bullet) Method

Left ventricular end-diastolic volume (LVEDV) calculation is important in decision making in children with congenital heart disease (CHD). This study examined the accuracy of LVEDV calculation by the formula: 5/6 x area x length ("bullet" method), by comparing echocardiographic (ECHO) LVEDV against cardiac magnetic resonance (CMR). ECHO and CMR data from 72 consecutive subjects with CHD < or =10 years of age were retrospectively reviewed. Exclusion criteria included: >3 months between examinations; unavailable or poor-quality images. Subxiphoid short- and long-axis echocardiographic images were analyzed. Bullet LVEDV was compared to CMR volumes. Seventeen subjects (median age 5.5 years, range 1-10 years) comprised the study group. ECHO and CMR LVEDV showed an excellent correlation (r = 0.97) and a good agreement with a mean difference (limits of agreement) of -1.0 mL (-13.9 to 11.9 mL). Subxiphoid echocardiographic bullet method of measuring LVEDV shows a good agreement with CMR obtained LV size in young children.

149 Assessment of left ventricular volumes and function by 3D real-time transthoracic echocardiography in children: Comparison of Qlab and Tomtec full volume reconstruction

Three-dimensional echocardiography (3DE) allows calculation of ventricular volumes without geometric assumption on the ventricular shape. Real Time 3DE is validated to evaluate left ventricular (LV) volumes and function in adults. Accuracy of the two full volume reconstruction softwares Tomtec and Qlab have not been yet studied in children. To apply 3DE in a normal pediatric population and to compare the left ventricular volumes measurements between these two analysing softwares. Fifty pediatric patients (median age 10 years) with normal cardiac anatomy and function were included. 3D transthoracic echocardiography was performed with the X4-2 or X7-2 matrix probe (ie33, Philips Medical Systems, Andover, MA). Off-line left ventricular (LV) volume analysis was performed with QLAB 6.0 (Semi-automated border detection with biplane projections) and TomTec 4D LV analysis (primarily manual tracking with triplane projections and semiautomated border detection). Feasibility was 94% for both softwares. Measurements of LV stroke volume, end-diastolic and end-systolic were strongly correlated (r = 0.96; p < 0.0001). LV ejection fraction measurements were well correlated between the 2 methods (r = 0.78; p <0,0001). Mean LV ejection fraction difference was 3.9% +/- 8. No difference was found between Qlab and Tomtec observer variability. Nevertheless Tomtec inter Observer variability tends to be higher. The analysis time was shorter with QLAB (5 +/- 2 min vs. 6 +/- 3, p < 0.05). 3DE is a feasible and adequate method for LV volume quantification in a normal pediatric population. Qlab analysis is faster, easier and inter-observer variability tends to be smaller. Further studies are needed to validate the accuracy of the method to calculate enlarged LV volumes in patients with congenital heart diseases.

Right ventricular remodelling in pulmonary arterial hypertension with three-dimensional echocardiography: comparison with cardiac magnetic resonance imaging

Right ventricular (RV) mass and volume calculations are important correlates of survival in patients with pulmonary arterial hypertension (PAH). We tested the hypothesis that RV mass, volumes and function could be measured accurately with real-time three-dimensional echocardiography (3DE) in patients with PAH and compared those against cardiac magnetic resonance (CMR). Sixty consecutive PAH patients and 20 normals were examined with 3DE and CMR. RV end-diastolic volumes (EDV), end-systolic (ESV), stroke volume (SV), ejection fraction (EF), and mass were measured in all patients and in normals. Two independent observers assessed variability using the Bland-Altman analysis agreement. RV volumes (in mL) and mass were similar between 3DE and CMR in PAH patients: [EDV (in mL) 183.2 +/- 38 vs. 187.3 +/- 41, P = 0.32; ESV (in mL) 122 +/- 33 vs. 126 +/- 36, P = 0.99; SV (in mL) 63 +/- 15 vs. 65 +/- 19, P = 0.06; EF (in %) 33 +/- 7 vs. 31 +/- 9, P = 0.16 and RV mass (g) 99 +/- 20 vs. 96 +/- 22, P = 0.42], respectively. Interobserver variability was similar between 3DE and CMR in PAH for all variables, with CMR showing less interobserver variability for EDV compared with 3DE in both patients and normals (patients: mean bias: CMR-EDV: 0.4 +/- 16 mL vs. 3DE-EDV: 6.9 +/- 17.9 and in normals: CMR-EDV: 0.1 +/- 9.8 vs. 3DE-EDV: 5.7 +/- 16.3, respectively), whereas EF and RV mass were poorly reproducible with no correlation between observers for 3DE and CMR. RV remodelling in PAH patients can be accurately assessed with both 3DE and CMR. Both modalities are robust and reproducible with CMR being more reproducible for measurements of EF and RV mass.

Repeatability and Reproducibility of Fetal Cardiac Ventricular Volume Calculations Using Spatiotemporal Image Correlation and Virtual Organ Computer-Aided Analysis

The objective of this study was to quantify the repeatability and reproducibility of fetal cardiac ventricular volumes obtained using spatiotemporal image correlation (STIC) and Virtual Organ Computer-Aided Analysis (VOCAL; GE Healthcare, Kretztechnik, Zipf, Austria). A technique was developed to compute ventricular volumes using the subfeature Contour Finder: Trace. Twenty-five normal pregnancies were evaluated for the following: (1) to compare the coefficient of variation (CV) of ventricular volumes obtained using 15 degrees and 30 degrees rotation; (2) to compare the CV between 3 methods of quantifying ventricular volumes: (a) Manual Trace, (b) Inversion Mode, and (c) Contour Finder: Trace; and (3) to determine repeatability by calculating agreement and reliability of ventricular volumes when each STIC was measured twice by 3 observers. Reproducibility was assessed by obtaining 2 STICs from each of 44 normal pregnancies. For each STIC, 2 ventricular volume calculations were performed, and agreement and reliability were evaluated. Additionally, measurement error was examined. (1) Agreement was better with 15 degrees rotation than 30 degrees (15 degrees: 3.6%; 95% confidence interval [CI], 3.0%-4.2%; versus 30 degrees: 7.1%; 95% CI, 5.8%-8.6%; P < .001); (2) ventricular volumes obtained with Contour Finder: Trace had better agreement than those obtained using either Inversion Mode (Contour Finder: Trace: 3.6%; 95% CI, 3.0%-4.2%; versus Inversion Mode: 6.0%; 95% CI, 4.9%-7.2%; P < .001) or Manual Trace (10.5%; 95% CI, 8.7%-12.5%; P < .001); (3) ventricular volumes were repeatable with good agreement and excellent reliability for both intraobserver and interobserver measurements; and (4) ventricular volumes were reproducible with negligible differences in agreement and good reliability. In addition, bias between STIC acquisitions was minimal (<1%; mean percent difference, -0.4%; 95% limits of agreement, -5.4%-5.9%). Fetal echocardiography using STIC and VOCAL allows repeatable and reproducible calculation of ventricular volumes with the subfeature Contour Finder: Trace.

Reply from Potkin, Siegel, and Chen

LETTERS TO THE EDITORReply from Potkin, Siegel, and ChenRalph Potkin, Robert Siegel, and Victor ChengRalph Potkin, Robert Siegel, and Victor ChengPublished Online:01 May 2008https://doi.org/10.1152/japplphysiol.00101.2008MoreSectionsPDF (27 KB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInEmailWeChat to the editor: We thank Marabotti and colleagues (1) for their letter addressing the use of subcostal echocardiographic imaging to assess right ventricular systolic function in our recent work regarding glossopharyngeal insufflation. The major concerns raised in the letter were twofold: that radionuclide ventriculography, rather than echocardiography, is the most accurate assessment of right ventricular volume, and that the volumes obtained in our calculations were significantly discordant from those obtained in the left ventricle and much smaller than expected in healthy persons.We considered several factors before selecting echocardiography to evaluate ventricular function in the elite divers. First, our primary interest was the change of ventricular function induced by glossopharyngeal insufflation, rather than a true measure of ventricular size and volume. In this respect, each diver at rest acted as his/her own control, and ventricular volume calculations were strictly used to demonstrate the degree of change in ventricular function. Second, subcostal echocardiographic assessment of right ventricular function has shown good correlation with radionuclide angiography in the past (2). Third, echocardiography allowed rapid, real-time imaging of cardiac function before, during, and after glossopharyngeal insufflation. In our hypothesis-generating investigation, it was the only noninvasive modality that achieves appropriate temporal and visual resolution for the requisite analysis while sparing participating divers ionizing radiation. Despite the known shortcomings of subcostal echocardiographic imaging when studying the geometrically complex right ventricle, it was still a strong modality to detect marked changes in ventricular function, and we firmly believe in the validity of the observed decline in right and left ventricular function during glossopharyngeal insufflation.The principal message in our study was that, for the first time, decrease in biventricular function due to glossopharyngeal insufflation has been demonstrated by direct cardiac imaging. We agree with Marabotti and colleagues that pursuing confirmation of our findings with “gold-standard” evaluation of right ventricular function is worthwhile. Perhaps more importantly, we believe, are future investigations to clarify the underlying mechanisms by which glossopharyngeal insufflation compromises cardiac performance.REFERENCES1 Marabotti C, Bedini R, L'Abbate A. Right ventricular volume determination: not a matter for echocardiography. J Appl Physiol; doi:10.1152/japplphysiol.00065.2008.Link | ISI | Google Scholar2 Panidis IP, Ren JP, Kotler MN, Mintz G, Iskandrian A, Ross J, Kane S. Two-dimensional echocardiographic estimation of right ventricular ejection fraction in patients with coronary artery disease. J Am Coll Cardiol 2: 911–918, 1983.Crossref | ISI | Google ScholarAUTHOR NOTESAddress for reprint requests and other correspondence: R. Potkin, Beverly Hills Center for Hyperbaric Medicine, 1125 S. Beverly Dr., Los Angeles, CA 90035 (e-mail: [email protected]) Download PDF Previous Back to Top FiguresReferencesRelatedInformation More from this issue > Volume 104Issue 5May 2008Pages 1548-1548 Copyright & PermissionsCopyright © 2008 the American Physiological Societyhttps://doi.org/10.1152/japplphysiol.00101.2008History Published online 1 May 2008 Published in print 1 May 2008 Metrics

Monitoring preload during liver transplantation

Liver transplantation is associated with major shifts incentral blood volume; therefore, monitoring preload is es-sential. Filling pressures (central venous pressure or pul-monary artery occlusion pressure) do not reflect preload[right ventricular end-diastolic volume (RVEDV) or leftventricular end-diastolic volume (LVEDV)] well becausethese pressures are affected not just by preload but alsoby changes in compliance of the heart. These compliancechanges can be quite significant because of the changesin chest volume that are the result of surgical retractionand variable pressure on the diaphragm. Then, what arethe alternative methods of preload monitoring in the op-erating room? There are only two: thermodilution deter-mination of RVEDV and transesophageal echocardio-graphic estimation of RVEDV and LVEDV. Each of thesetechniques has advantages and disadvantages.The clinical determination of the right ventricularejection fraction (RVEF) and RVEDV became possible inthe early 1980s when American Edwards Laboratoriesmarketed a pulmonary artery catheter with a fast-re-sponse thermistor and an accompanying computer.That technology was based on intermittent injection ofa cold solution as a dye, and the principle of conserva-tion of energy allowed the calculation of RVEF and rightventricular volumes.

Real-time three-dimensional echocardiography in aortic stenosis: a novel, simple, and reliable method to improve accuracy in area calculation

The aim of the study was to validate a novel formula for aortic area, based on the principle of continuity equation (CE), that substitutes Doppler-derived stroke volume (SV) by SV directly measured with real-time three-dimensional (RT3D) echo and semi-automated border detection. RT3D has proved outstanding accuracy for left ventricular volume calculation. So far, however, neither this potential has been applied to haemodynamic assessment, nor RT3D has succeeded in the evaluation of aortic valve disease. Aortic area was measured in 41 patients with aortic stenosis using Gorlin's equation, Hakki's formula, Doppler CE, two-dimensional Simpson's volumetric method, and by the novel RT3D method. RT3D has the best linear association and absolute agreement with Gorlin of all non-invasive methods r = 0.902, intraclass correlation coefficient (ICC) = 0.846, better than CE (r = 0.646, ICC = 0.626) and two-dimensional volumetric method (r = 0.627, ICC = 0.378). Linear and Passing-Bablok regression show that RT3D fits better to Gorlin (r(2) = 0.814) than CE (r(2) = 0.417) and two-dimensional method (r(2) = 0.393). Its accuracy is comparable to Hakki's formula, routinely employed in catheter laboratories. Inter- and intraobserver agreements (ICC) were, respectively, 0.732 and 0.985, better than CE (0.662, 0.857). RT3D also grades most efficiently the severity of aortic stenosis as mild, moderate, or severe (weighted kappa = 0.932). RT3D underestimates aortic area (95% CI 0.084-0.193). ROC curves, however, show that the optimal cutoff point to consider aortic stenosis severity remains close to 1 cm(2) (1.06 cm(2)). RT3D is more accurate than CE and than two-dimensional volumetric methods to calculate area and to grade the severity of aortic stenosis. Area obtained by three-dimensional echo is slightly underestimated, but its range is clinically negligible.

Accuracy and Feasibility of Online 3-Dimensional Echocardiography for Measurement of Left Ventricular Parameters

The availability of automated online software may increase the feasibility of real-time 3-dimensional (3D) echocardiography (3DE) for left ventricular (LV) volume calculation in clinical practice. We sought to compare offline and online approaches with magnetic resonance imaging (MRI). Patients who presented to the clinical laboratory for evaluation of LV parameters (n = 110, 94 men, age 63 +/- 10 years) were studied with 2-dimensional echocardiography, online and offline 3DE, and MRI. The 3DE measurements were obtained by a semiautomated LV border detection based on tracing (online) and edge detection (offline). MRI images were obtained using true free induction steady-state precession during breath hold, with measurement of 3D volumes and ejection fraction (EF). All echocardiographic techniques underestimated LV volumes, but EF estimations were similar. The best correlation was between MRI versus offline 3DE. The correlation of online 3DE with MRI was significantly better than 2-dimensional echocardiography (end-diastolic volume (EDV) z = 4.2, end-systolic volume (ESV) z = 4.44, EF z = 4.32; all P < .01). However, correlation of offline 3DE with MRI was significantly better than online 3DE (EDV z = 2.57, P < .05; ESV z = 2.42, P < .05; EF z = 3.82, P < .01). Images were considered to be good quality (endocardium visualized in all walls) in 49 patients; discrepancies between online and offline 3DE and MRI were similar in good- and poor-quality images. Wall-motion abnormalities were present in 98 patients; discrepancies with MRI were similar in patients with and without abnormal wall motion. Online measurement of LV volumes is feasible and more accurate than with 2-dimensional echocardiography. Although the offline approach is more accurate, it is also more time-consuming.

Integrated cardio-thoracic imaging with ECG-Gated 64-slice multidetector-row CT: initial findings in 133 patients

The purpose of this study was to investigate the possibility of assessing the underlying respiratory disease as well as cardiac function during ECG-gated CT angiography of the chest with 64-slice multidetector-row CT (MDCT). One hundred thirty-three consecutive patients in sinus rhythm with known or suspected ventricular dysfunction underwent an ECG-gated CT angiographic examination of the chest without beta-blockers using the following parameters: (1) collimation: 32 x 0.6 mm with z-flying focal spot for the acquisition of 64 overlapping 0.6-mm slices (Sensation 64; Siemens); rotation time: 0.33 s; pitch: 0.3; 120 kV; 200 mAs; ECG-controlled dose modulation (ECG-pulsing) and (2) 120 ml of a 35% contrast agent. Data were reconstructed: (1) to evaluate the underlying respiratory disease (1-mm thick lung and mediastinal scans reconstructed at 55% of the R-R interval; i.e., "morphologic scans") and (2) to determine right (RVEF) and left (LVEF) ventricular ejection fractions (short-axis systolic and diastolic images; Argus software; i.e., "functional scans"). The mean heart rate was 73 bpm (range: 42-120) and the mean scan time was 18.11 +/- 2.67 s (range: 10-27). A total of 123 examinations (92%) had both lung and mediastinal images rated as diagnostic scans, whereas 10 examinations (8%) had non-diagnostic images altered by the presence of respiratory-motion artifacts (n = 4) or cyclic artifacts related to the use of a pitch value of 0.3 in patients with a very low heart rate during data acquisition (n = 6). Assessment of right and left ventricular function was achievable in 124 patients (93%, 95% CI: 88-97%). For these 124 examinations, the mean RVEF was 46.10% (+/- 9.5; range: 20-72) and the mean LVEF was 58.23% (+/- 10.88; range: 20-83). In the remaining nine patients, an imprecise segmentation of the right and left ventricular cavities was considered as a limiting factor for precise calculation of end-systolic and end-diastolic ventricular volumes. The mean (+/- SD) DLP value of the examinations was 279.86 (+/- 117.50) mGy.cm. Assessment of underlying respiratory disease and cardiac function from the same data set was achievable in 92% of the patients with ECG-gated 64-slice MDCT.

Effect of angiotensin-converting enzyme or vasopeptidase inhibition on ventricular size and function in patients with heart failure: The Omapatrilat Versus Enalapril Randomized Trial of Utility in Reducing Events (OVERTURE) echocardiographic study

Angiotensin-converting enzyme (ACE) inhibition attenuates ventricular remodeling and improves ventricular function in heart failure patients. Vasopeptidase inhibition has shown similar effects in experimental models. The OVERTURE echocardiographic study was designed to test the hypothesis that the vasopeptidase inhibitor omapatrilat would attenuate ventricular remodeling and improve ventricular function to a greater extent than an ACE inhibitor. Three hundred twenty-one patients with heart failure (New York Heart Association class > or = 2) were included in the OVERTURE echocardiographic substudy and were randomized to receive enalapril (10 mg twice a day) or omapatrilat (40 mg every day). Echocardiograms were performed at baseline and at 1 year (n = 214). Left ventricular size was estimated by summation of ventricular areas in apical and short-axis views and by calculation of ventricular volumes. Ejection fraction was calculated from ventricular volumes. Combined diastolic and systolic areas and volumes decreased significantly (mean diastolic area change -8.36 cm2, 95% CI -9.4 to -7.3 cm2; mean systolic change -8.4 cm2, 95% CI -9.5 to -7.3 cm2), and ejection fractions increased significantly (3.6%, 95% CI 2.6% to 4.6%) in both treatment groups from baseline to 1 year. There were no differences in the magnitude of improvement in ventricular size or function based on treatment assignment. Patients who died or were hospitalized for heart failure subsequent to the final assessment demonstrated the least degree of reverse remodeling. Ventricular size and function improved similarly after 1 year with ACE or vasopeptidase inhibition in patients with heart failure. Reverse remodeling was associated with improved outcome.

Semiautomatic detection of left ventricular contours in contrast-enhanced echocardiographic images: Comparison with magnetic resonance imaging

The aim of this study was to evaluate the accuracy of a semiautomatic contour detection method for left ventricular (LV) volume calculation in contrast-enhanced echocardiographic images. In 26 patients, LV volumes were automatically measured by magnetic resonance imaging and second harmonic echocardiography after intravenous Levovist administration. LV cavity edges were manually drawn and semiautomatically outlined using the active contour algorithm, improved by a nonlinear anisotropic filter; LV volumes were calculated by the modified Simpson's rule. Manual and semiautomatic analysis of echocardiographic images lasted 45 ± 6 and 20 ± 8 seconds, respectively. Contrast echocardiography volumes were smaller than those by magnetic resonance imaging (mean difference: 16 mL for manual and 18 mL for automatic analysis). LV volumes by echocardiography closely related with those by magnetic resonance imaging using both manual ( r = 0.955) and semiautomatic ( r = 0.945) analysis; the correlation was closer for end-systolic than for end-diastolic volumes. In conclusion, this method provides a fast measure of LV volumes in contrast-enhanced images while reducing operator dependency.

A Reliable and Efficient Method for Cerebral Ventricular Volumetry in Pediatric Neuroimaging

Cerebral ventricular volume has the potential to become an important parameter in quantitative neurological diagnosis. However, no accepted methodology for routine clinical use exists to date. We sought a robust, reproducible, and fast technique to evaluate cerebral ventricular volume in young children. We describe a novel volumetric methodology to segment and visualize intracerebral fluid spaces and to quantify ventricular volumes. The method is based on broadly available T1 weighted volumetric magnetic resonance (MR) imaging, an interactive watershed transform, and a fully automated histogram analysis. We evaluated this volumetric methodology with 34 clinical volumetric MR datasets from non-sedated children (age 6-7 y) with a history of prematurity and low birth weight (< or = 1500 g) obtained during a prospective study. The methodology, with adaptation for small ventricular size, was capable of evaluating all 34 of the pediatric datasets for cerebral ventricular volume. The method was a) robust for normal and pathological anatomy, b) reproducible, c) fast with less than five minutes for image analysis, and d) equally applicable to children and adults. Clinical brain ventricular volume calculations in non-sedated children can be performed using routine MR imaging besides efficient three-dimensional segmentation and histogram analysis with results that are robust and reproducible.