Volumetric analysis of the right and left ventricle in a porcine heart model: comparison of three-dimensional echocardiography, magnetic resonance imaging and angiocardiography

Normative ranges of biventricular volumes and function in healthy term newborns

BACKGROUND

Cardiovascular magnetic resonance (CMR) is increasingly used in newborns with congenital heart disease. However, reporting on ventricular volumes and mass is hindered by an absence of normative data in this population.

DESIGN/METHODS

Healthy term (37-41 weeks gestation) newborns underwent non-sedated, free-breathing CMR within the first week of life using the 'feed and wrap' technique. End-diastolic volume (EDV), end-systolic volume (ESV) stroke volume (SV) and ejection fraction (EF) were calculated for both left ventricle (LV) and right ventricle (RV). Papillary muscles were separately contoured and included in the myocardial volume. Myocardial mass was calculated by multiplying myocardial volume by 1.05 g/ml. All data were indexed to weight and body surface area (BSA). Inter-observer variability (IOV) was performed on data from 10 randomly chosen infants.

RESULTS

Twenty healthy newborns (65% male) with a mean (SD) birth weight of 3.54 (0.46) kg and BSA of 0.23 (0.02) m2 were included. Normative LV parameters were indexed EDV 39.0 (4.1) ml/m2, ESV 14.5 (2.5) ml/m2 and ejection fraction (EF) 63.2 (3.4)%. Normative RV indexed EDV, ESV and EF were 47.4 (4.5) ml/m2, 22.6 (2.9) ml/m2 and 52.5 (3.3)% respectively. Mean LV and RV indexed mass were 26.4 (2.8) g/m2 and 12.5 (2.0) g/m2, respectively. There was no difference in ventricular volumes by gender. IOV was excellent with an intra-class coefficient > 0.95 except for RV mass (0.94).

CONCLUSION

This study provides normative data on LV and RV parameters in healthy newborns, providing a novel resource for comparison with newborns with structural and functional heart disease.

Non-Invasive Assessment of Left Ventricle Ejection Fraction: Where Do We Stand?

The left ventricular (LV) ejection fraction (EF) is the preferred parameter applied for the non-invasive evaluation of LV systolic function in clinical practice. It has a well-recognized and extensive role in the clinical management of numerous cardiac conditions. Many imaging modalities are currently available for the non-invasive assessment of LVEF. The aim of this review is to describe their relative advantages and disadvantages, proposing a hierarchical application of the different imaging tests available for LVEF evaluation based on the level of accuracy/reproducibility clinically required.

Comparison of Right Ventricular Function Between Three-Dimensional Transesophageal Echocardiography and Pulmonary Artery Catheter

OBJECTIVE

This study aimed to compare measurements of right ventricular function using three-dimensional transesophageal echocardiography (3D TEE), and pulmonary artery catheters (PACs) in patients undergoing cardiac surgery. The authors examined the practicality of using the 3D TEE.

DESIGN

Prospective observational.

SETTING

Cardiac operating room at a single university hospital.

PARTICIPANTS

All adult patients undergoing elective cardiac surgery at a single tertiary care university hospital over two years.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Right ventricular end-diastolic volume (RVEDV), right ventricular end-systolic volume (RVESV), stroke volume (SV), and right ventricular ejection fraction (RVEF) were measured with both 3D TEE and PACs. Assessments were performed using correlation coefficients, paired t tests, and Bland-Altman plots. Thirty-one patients participated in this study. Each measurement showed good agreement. RVEDV and RVESV were slightly lower on 3D TEE than on PAC (205.9 mL v 220.2 mL, p = 0.0018; 143.0 mL v 155.5 mL, p = 0.0143, respectively), whereas no significant differences were observed for SV and RVEF (31.0% v 31.1%, p = 0.0569; 61.6 mL v 66.9 mL, p = 0.92, respectively). Linear regression analysis showed high correlation between 3D TEE and PAC for RVEDV (r = 0.87) and RVESV (r = 0.81), and moderate correlation for SV (r = 0.67) and RVEF (r = 0.67). In the Bland-Altman plot, most patients were within the 95% limits of the agreement throughout all measurements.

CONCLUSION

A high correlation was found between measurements made with a PAC and with 3D TEE in the assessment of right ventricular function. Three-dimensional TEE would be a potential alternative to PAC for assessment of right ventricular function during intraoperative periods.

Assessing Right Ventricular Function in the Perioperative Setting, Part II: What About Catheters?

An-depth assessment of right ventricular function is important in a many perioperative settings. After exploring 2-dimensional echo-based evaluation, other proposed monitoring modalities are discussed. Pressure-based methods of right ventricular appraisal is discussed. Flow-based assessment is reviewed. An overview of the state of current right ventricular 3-dimensional echocardiography and its potential to construct clinical pressure-volume loops in conjunction with pressure measurements is provided. An overview of right ventricular assessment modalities that do not rely on 2-dimensional echocardiography is discussed. Tailored selection of monitoring modalities can be of great benefit for the perioperative physician. Integrating modalities offers optimal estimations of right ventricular function.

A closer look at right ventricular 3D volume quantification by transthoracic echocardiography and cardiac MRI

AIM

To compare right ventricular (RV) volumetry using state-of-the-art three-dimensional (3D) transthoracic echocardiography (3DE) and cardiac magnetic resonance imaging (CMR) near-simultaneously in a clinical setting.

MATERIALS AND METHODS

Forty-seven consecutive patients received comprehensive echocardiography including 3DE within 30 minutes of CMR. RV volumetry was performed offline with semi-automated 3D endocardial border tracing as well as manual delineation of the compacted myocardium in short-axis views by CMR.

RESULTS

Forty-two examinations (89%) could be analysed offline by 3D RV reconstruction. Mean RV volumes assessed by CMR and 3DE were 215±63 and 127±42 ml for end-diastole (RV-EDV), as well as 110±43 and 62±27 ml for end-systole (RV-ESV). RV-EDV, RV-ESV, and RV stroke volume measured by 3DE were significantly lower than RV volumetry by CMR. Mean bias were -88, -48, and -41 ml, respectively. Mean RV ejection fraction (-EF) showed a non-significant deviation of +2% between 3DE and CMR and the correlation coefficient was r=0.58 for RV-EF.

CONCLUSION

RV-EF can be assessed reliably using transthoracic 3DE in patients with good image quality; however, absolute RV volumes measured by 3DE show a systematic deviation to CMR volumetry that has been previously neglected and requires careful interpretation regarding anatomical cardiac imaging.

Fetal Cardiac Functional Assessment by Fetal Heart Magnetic Resonance Imaging

OBJECTIVE

We attempted to evaluate fetal cardiac activity of congenital heart disease (CHD) and normal heart fetuses by magnetic resonance imaging (MRI).

METHODS

We evaluated the fetal cardiac functional assessment and the blood flow of descending aorta at 34 weeks' gestation or more by MRI and compared the results with ultrasonography findings. We measured 6 normal heart fetuses and 14 CHD fetuses.

RESULTS

The ejection fraction (EF) and descending aorta blood flow in the CHD group were 76.4% ± 11.9%, 687.5 ± 303.8 mL/min by ultrasonography and 48.3% ± 7.1%, 711.4 ± 273.1 mL/min by MRI; those in the normal group were 66.9% ± 12.2%, 898.1 ± 245.9 mL/min by ultrasonography and 51.3% ± 4.2%, 911.9 ± 223.1 mL/min by MRI.

CONCLUSIONS

There was no significant difference in descending aorta blood flow measurements between ultrasonography and MRI, but the EF showed a significant between-group difference. In the normal group, the variation of EF and blood flow measured by MRI was significantly smaller compared with those of ultrasonography.

5/6 Area length method for left-ventricular ejection-fraction measurement in adults with repaired tetralogy of Fallot: comparison with cardiovascular magnetic resonance

In patients with repaired tetralogy of Fallot (rTOF), left-ventricular ejection fraction (LVEF) predicts adverse outcomes. Two-dimensional echocardiographic (2DE) methods of measuring LVEF require geometric assumptions and may be limited in this population due to altered ventricular geometry. This study evaluated the performance of the 5/6 area × length (AL) method in this population as well as which factors limit agreement with the results of cardiovascular magnetic resonance (CMR). In 20 patients with rTOF (28.5 ± 14.7 years old) and CMR and 2DE within 3 months, two investigators blinded to CMR measured LVEF from 2DE by the AL method, biplane Simpson's (BiS) method, and visual estimate. Two investigators blinded to 2DE measured LVEF from CMR by Simpson's and AL methods. The AL method on 2DE more closely approximated LVEF by CMR (r = 0.73, p = 0.0003) than BiS method (r = 0.53, p = 0.02). AL method was not limited by geometric assumptions, as AL method on CMR closely approximated Simpson's method on CMR (r = 0.90, p < 0.0001) despite median left-ventricular diastolic eccentricity index of 1.24. AL method on 2DE was primarily limited by short-axis area measurement rather than foreshortening of the ventricle. In conclusion, in adults with rTOF, AL method on 2DE moderately approximates LVEF by CMR, even in the context of altered left-ventricular geometry. Although the AL method may be the most appropriate 2DE method in this population, significant limitations remain for LVEF assessment by 2DE, and strategies to optimize image position and border detection are essential.

Rapid and accurate quantification of right ventricular volume and stroke volume by real-time 3-dimensional triplane echocardiography

BACKGROUND

Previous studies have demonstrated that 3-Dimensional (3-D) echocardiography can determine right ventricular (RV) volume accurately. However, this technique has not been feasible in everyday clinical practice because of the necessity of time-consuming off-line processes.

HYPOTHESIS

A newly developed real-time 3-D triplane echocardiography, which acquires 3 apical rotational cross-sectional images simultaneously, holds the promise to resolve these problems.

METHODS AND RESULTS

Sixteen excised formalin fixed porcine hearts and 24 healthy human subjects underwent real-time 3-D triplane echocardiography. In an anatomic in vitro study, the actual volume of RV was obtained by spilling water in the RV cavity into a graduated cylinder for measurement, which served as a reference standard for comparison. For healthy subjects, the RV stroke volume (SV) was measured by triplane echocardiography which was compared with the left ventricular (LV) SV obtained by conventional 2-Dimensional echocardiography (2-DE). Excellent correlation and agreement between 3-D triplane imaging derived RV volume and the actual one for excised porcine hearts were observed (r = 0.979, p < 0.001, mean difference 2.2 mL). In healthy human subjects, good correlation and agreement between 3-D triplane imaging derived RV SV and LV SV measured by 2-DE were obtained (r = 0.970, p < 0.001, mean difference 5.9 mL).

CONCLUSIONS

Real-time 3-D triplane echocardiography provides us a new method for rapid and accurate quantification of RV volume. Furthermore, this new method holds the promise for evaluating RV volume and SV in routine clinical practice.

Effect of angiotensin receptor blockade on systemic right ventricular function and size: a small, randomized, placebo-controlled study

INTRODUCTION

The effects of angiotensin converting enzyme inhibitor on systemic right ventricular size and function are unknown.

METHODS

Prospective, double blind, randomized, placebo-controlled clinical trial of 1-year therapy with Ramipril in adult patients with DTGA status postatrial baffle procedure. Primary endpoints were change in systemic right ventricular ejection fraction (RVEF) and right ventricular size assessed by magnetic resonance imaging (MRI).

RESULTS

Seventeen patients were enrolled into the study. Mean age at study enrollment was 26.4+/-5.2 years. Mean baseline RVEF was 44+/-6.5%, mean RVEDV was 206.3+/-75.5 ml. Eight patients were randomized to the treatment group and 9 patients were randomized to the placebo group. RVEF did not improve in the Ramipril group from baseline to 1 year (43.8+/-7.1% vs. 40.9+/-13.3%, p=0.52) and remain unchanged in the placebo group (44.3+/-6.3 vs. 46.3+/-9.6%, p=0.42). RVEDV (184.5+/-56.4 ml vs. 179.6+/-66.4 ml, p=0.64) and RVESV (109.5+/-19.4 ml vs. 111.8+/-30.1, p=0.74) remained unchanged in the Ramipril group from baseline to 1 year as well as in the placebo group (228.1+/-89.2 ml vs. 204.5+/-50.4 ml, p=0.42 and 117.5+/-36.9 ml vs. 117.4+/-26.2 ml, p=0.99, respectively).

CONCLUSION

One-year treatment with Ramipril does not seem to affect right ventricular function or size in adult patients with systemic right ventricles after a Mustard or Senning procedure.

CONDENSED ABSTRACT

17 Adult patients (mean age of 26.4 +/- 5.2 years) with systemic right ventricles were blindly randomized to 1-year treatment with Ramipril placebo. Systemic right ventricular function (RVEF) and size (RVEDV) were assessed by magnetic resonance imaging at baseline and 1 year. RVEF failed to improve in the Ramipril group (43.8+/-7.1% vs. 40.9+/-13.3%, p=0.52) and remain unchanged in the placebo group (44.3+/-6.3 vs. 46.3+/-9.6%, p=0.42). RVEDV remained unchanged in the study group (184.5+/-56.4 ml vs. 179.6+/-66.4 ml, p=0.64 as well as in the placebo group (228.1 +/- 89.2 ml vs. 204.5 +/- 50.4 ml, p = 0.42). One-year treatment with Ramipril does not improve right ventricular function or attenuate remodeling in adult patients with systemic right ventricles.

How accurately, reproducibly, and efficiently can we measure left ventricular indices using M-mode, 2-dimensional, and 3-dimensional echocardiography in children?

BACKGROUND

Measurements of left ventricular (LV) size, mass, and function are the most common and important tasks for echocardiography in clinical practice and research in children with congenital and acquired heart diseases. There are little data to compare the utility of M-mode (MM), 2-dimensional (2D), and 3-dimensional (3D) echocardiographic techniques for quantification of LV indices. The objective of the study was to assess the accuracy, reproducibility, and efficiency of these echocardiographic methods for measurement of LV indices in children.

METHODS

A prospective study was conducted in 20 consecutive children (mean 10.6 +/- 2.8 years, 11 male and 9 female subjects) using conventional MM, 2D, and real-time 3D echocardiography (RT3DE). A Sonos 7500 system (Philips Medical Systems, Andover, MA) was used. M-mode and 2DE measurements were made according to the American Society of echocardiography recommendations. To include the entire LV for volumetric measurement, full-volume 3D data sets were acquired from 4 electrocardiogram gated subvolumes. The 3DE measurements were made off-line manually using 4-plane and 8-plane algorithms by 4D Echo-View (TomTec Imaging Systems, Munich, Germany) and a semiautomated algorithm by QLAB (Philips Medical Systems). Magnetic resonance imaging studies were also performed to determine the LV indices by a disk summation method based on the Simpson principle.

RESULTS

The correlation and agreement between MM, 2D, and RT3D echocardiography and magnetic resonance imaging measurements are good (r = 0.81-0.97) for the 3 methods. The correlation was superior for RT3DE compared with 2DE and MM. The correlation and agreement were similar for the three 3DE methods. The intra- and interobserver variabilities ranged from MM (4.3%-4.8% and 7.0%-8.7%), 2DE (3.3%-4.5% and 5.5%-7.3%), and 3DE (0.4%-2.3%, and 0.2%-4.8%). The total time (acquisition and analysis) used for MM measurements was the least compared with 2DE and 3DE. The total time for 3DE using the semiautomated algorithms was not significantly different compared with that for 2DE.

CONCLUSIONS

Our study showed that MM provides the most efficient assessment of LV indices but is the least accurate and reproducible technique compared with 2DE and 3DE. Three-dimensional echocardiography using both automated and manual analysis algorithm is superior to MM and 2DE for measurements of LV indices, and the automated 3DE algorithm is as efficient as 2DE. Therefore, 3DE using the automated algorithm is the method of choice for quantification of LV indices.

Accuracy and reproducibility of real-time three-dimensional echocardiography for assessment of right ventricular volumes and ejection fraction in children

BACKGROUND

Measurement of right ventricular (RV) volumes and ejection fraction (EF) by two-dimensional echocardiography has limited accuracy and reproducibility because of the complex RV geometry.

OBJECTIVES

This study sought to validate real-time three-dimensional echocardiography (RT3DE) using a disk summation method for assessment of RV volumes and RVEF in children by comparing it with magnetic resonance imaging (MRI) measurements.

METHODS

A total of 20 children (mean age 10.6 +/- 2.8 years) were studied. Transthoracic RT3DE was performed using a RT3DE system to acquire full-volume RT3DE data sets from apical windows and data were processed offline using a software package. RV end-systolic volume and end-diastolic volume (EDV) were measured using a disk summation method by manually tracing the endocardial borders. RVEF was calculated as: RVEF = (EDV - end-systolic volume)/EDV x 100%. All participants also underwent MRI studies for comparison of RV indexes.

RESULTS

Of the 20 children, 3 were excluded because of poor or incomplete RV images (two RT3DE and one MRI study). For the remaining 17 children, good correlation and agreement between RT3DE and MRI were found (RVEDV: r = 0.98, P < .001, mean difference = -7.0 +/- 9.0 mL, P < .01; RV end-systolic volume: r = 0.96, P < .001, mean difference = -3.2 +/- 7.1 mL, P > .05; RVEF: r = 0.89, P < .001, mean difference = -0.3 +/- 7.1%, P > .05). The intraobserver and the interobserver variabilities ranged from -1.1% to 5.8%.

CONCLUSION

Measurement of RV volumes and EF by RT3DE is feasible, accurate, and reproducible in children compared with MRI measurements.

Quantification of right ventricular volumes and function by real time three-dimensional echocardiographic longitudinal axial plane method: validation in the clinical setting

BACKGROUND

Measurement of right ventricular (RV) volumes and right ventricular ejection fraction (RVEF) by three-dimensional echocardiographic (3DE) short-axis disc summation method has been validated in multiple studies. However, in some patients, short-axis images are of insufficient quality for accurate tracing of the RV endocardial border. This study examined the accuracy of long-axis analysis in multiple planes (longitudinal axial plane method) for assessment of RV volumes and RVEF.

METHODS

3DE images were analyzed in 40 subjects with a broad range of RV function. RV end-diastolic (RVEDV) and end-systolic volumes (RVESV) and RVEF were calculated by both short-axis disc summation method and longitudinal axial plane method.

RESULTS

Excellent correlation was obtained between the two methods for RVEDV, RVESV, and RVEF (r = 0.99, 0.99, 0.94, respectively; P < 0.0001 for all comparisons).

CONCLUSION

3DE longitudinal-axis analysis is a promising technique for the evaluation of RV function, and may provide an alternative method of assessment in patients with suboptimal short-axis images.

Reproducibility of Right Ventricular Volumes and Ejection Fraction Using Real-time Three-Dimensional Echocardiography

OBJECTIVES

The nongeometric nature of the right ventricle (RV) makes it difficult to measure. We sought to determine whether real-time three-dimensional echocardiography (RT3DE) is superior to two-dimensional echocardiography (2DE) for the follow-up of RV function by validation vs cardiac MRI.

METHODS

RV volumes and ejection fraction (EF) were studied with 2DE (including area-length [A-L], the modified two-dimensional subtraction [2DS] method, and the Simpson method of discs), RT3DE, and MRI in 50 patients with left ventricular wall motion abnormalities, the results of which suggested possible RV infarction. Test-retest variation was performed by a complete restudy using a separate sonographer within 24 h without the alteration of hemodynamics or therapy. Interobserver and intraobserver variations were noted in a subgroup of 20 patients.

RESULTS

EF estimations were similar using each technique. The mean (+/- SD) MRI end-diastolic volume (87 +/- 22 mL) was only slightly underestimated by RT3DE (mean difference, -3 +/- 10; p < 0.05), with a greater mean difference for 2DE A-L (-29 +/- 10; p < 0.05), and the Simpson method of discs (-29 +/- 23; p < 0.05), and was greatly overestimated by 2DS (mean difference, 26 +/- 23; p < 0.05). Similarly, the mean MRI end-systolic volume (46 +/- 17 mL) was only slightly underestimated by RT3DE (-4 +/- 7; p < 0.05), compared with 2DE A-L (-16 +/- 8; p < 0.05) and the Simpson method of discs (-16 +/- 8; p < 0.05), and was overestimated by 2DS (14 +/- 13; p < 0.05). RT3DE findings had a higher correlation with each parameter than any 2DE technique. There was also good intraobserver and interobserver correlation between RT3DE by two sonographers. RT3DE had less test-retest variation of RV volumes and EF than any 2DE measure.

CONCLUSIONS

RT3DE is more accurate than two-dimensional approaches and reduces the test-retest variation of RV volumes and EF measurements in follow-up RV assessment.

Right ventricular parameters: prospect for routine assessment by equilibrium radionuclide angiographic SPECT

While left ventricular (LV) function is assessed routinely for heart disease, right ventricular (RV) assessment has attracted relatively little attention due to technical difficulties, even though RV function plays an important role in determining prognosis. This issue of the Communications includes a report that a SPECT ERNA algorithm applied to data for patients with tetralogy of Fallot exhibited RV dysfunction compared to normal subjects, as reported previously using different ERNA SPECT algorithms. That ERNA SPECT methods appear to produce results that are expected of patient group who should exhibit RV abnormalities presents the prospect that such algorithms also could be used to evaluate whether patients undergoing chemotherapy with anthracyclines and other cardiotoxic chemotherapeutic agents become at risk of developing RV, as well as, LV dysfunction. SPECT ERNA may well become the standard test for monitoring RV and LV components of heart disease in managing patients undergoing chemotherapy.

Analysis of cardiac function--comparison between 1.5 Tesla and 3.0 Tesla cardiac cine magnetic resonance imaging: preliminary experience

PURPOSE

We sought to assess the feasibility of magnetic resonance imaging to evaluate cardiac function at 3.0 T compared with 1.5 T.

MATERIAL AND METHODS

In a prospective intraindividual comparative study, 12 volunteers (range, 18-54 years), and 2 patients (range, 43-53 years) underwent cardiac cine magnetic resonance at both 3.0 T and 1.5 T. Data were acquired both with a steady-state free precession sequence (SSFP) and a spoiled gradient echo (SGE) sequence. If necessary, a frequency scout was used to correct for off-resonance artifacts. For both SSFP and SGE imaging, 6-mm thick retrospectively EKG-gated short axis views were acquired with equal matrix size (192 x 163) and comparable repetition time (TR). Cardiac function parameters were determined manually by a single investigator. Cardiac function parameters, signal to noise ratio (SNR), contrast to noise ratio (CNR), and the presence of artifacts were compared between the 2 magnetic field strengths. For statistical analysis, a Pearson's correlation coefficient was calculated, and a paired Student t test was used to test statistical significance.

RESULTS

Very good correlations between cardiac function parameters at 1.5 T and 3.0 T (r > 0.84, P < 0.0011) were obtained. Compared with SGE, SSFP more frequently was prone to artifacts. With SSFP/SGE at 3.0 T, a SNR gain of 9.4/16% was achieved compared with 1.5 T.

CONCLUSION

Functional cardiac cine magnetic resonance imaging can be regarded as equally accurate at 3.0 T compared with 1.5 T. Compared with SSFP imaging, the SGE sequence benefits more from higher field strengths and is less affected by artifacts.

Transesophageal 3-dimensional versus cross-sectional echocardiographic assessment of the volume of the right ventricle in children with atrial septal defects

The study was designed to investigate the value of assessing right ventricular volume by transoesophageal 3-dimensional echocardiographic techniques compared with the standard transoesophageal cross-sectional approach. Echocardiography was performed using a multiplane probe. The 3-dimensional data sets were reconstructed after electrocardiographic and respiratory gated scanning, calculating the 3-dimensional volumes by the method of multiple slices. Cross-sectional determination of volume was performed using a modified area-length method, and the biplane multiple slice method following Simpson's rule. We studied 15 patients, with ages ranging from 6 to 19 years, and body surface areas from 1.1 to 1.67 square metres. It proved possible top determine volumes with both methods in all patients. As determined by 3-dimensional echo, volumes were greater, being 113.0 plus or minus 61.2 millilitres at end-systole, and 61.7 plus or minus 36 millilitres at end-diastole, than those calculated from cross-sectional images using Simpson's rule, which gave values of 92.5 plus or minus 52 millilitres, and 41.3 plus or minus 22 millilitres. Compared to the values obtained using the area-length method, at 116.9 plus or minus 61 millilitres, and 60.3 plus or minus 30 millilitres, there were only small differences at end-systole, with a bias of 1.4, and limits of agreement of 20.9 millilitres, as well as at end-diastole, when bias was minus 3.8, and limits of agreement 22.3 millilitres. Correlation was also good, with coefficients of 0.93, and 0.91, respectively. The mean difference between the volumes by 3-dimensional acquisition and the multiple slice method was larger, with higher limits of agreement, at end-diastole showing bias of 20.5, and limits of agreement of 30.1 millilitres, and for end-systole bias of 20.4, and limits of agreement of 32.2 millilitres. Our data confirm that cross-sectional echocardiographic assessment of right ventricular volumes in children with atrial septal defects is quick, and reasonably reliable in clinical practice when employing the area-length method.

Feasibility and variability of three dimensional echocardiography in arrhythmogenic right ventricular dysplasia/cardiomyopathy

Arrhythmogenic right ventricular dysplasia (ARVD/C) is a genetic cardiomyopathy characterized by fibrous fatty replacement of the right ventricular (RV) myocardium, leading to progressive RV failure and ventricular arrhythmias in young athletes. This study evaluated whether transthoracic, real-time, 3-dimensional echocardiography (3DE) can adequately assess RV morphology and function in ARVD/C by comparing 3DE with cardiac magnetic resonance (CMR), the current reference standard. Three-dimensional echocardiography was prospectively performed in 58 patients (23 with ARVD/C, 20 first-degree relatives with no ARVD/C, 8 with idiopathic ventricular tachycardia with no ARVD/C, and 7 healthy volunteers). All patients, except 15 patients with ARVD/C with implanted defibrillators, also underwent CMR. Three-dimensional echocardiography and CMR-derived RV volumes and ejection fractions were obtained by offline data analysis by blinded, independent observers. The mean age of the study group was 37 +/- 11 years (30 men). The feasibility of 3DE was high, and analyzable images were obtained in all subjects. Three-dimensional echocardiography revealed a wide variety of RV morphologic abnormalities in ARVD/C. There was a good correlation between 3DE and CMR for RV end-systolic volume (r = 0.72, p = 0.0001), RV end-diastolic volume (r = 0.50, p = 0.0001), and the RV ejection fraction (r = 0.88, p = 0.001). We found high intraobserver and moderate interobserver correlations for 3DE estimations of volumes and ejection fractions. In conclusion, 3DE measurements of RV volumes and ejection fractions closely correlate with CMR values and may be useful in the follow-up of patients with ARVD/C.

The emerging role of MRI in the diagnosis and management of cardiomyopathies

Cardiac magnetic resonance (CMR) has emerged as an important tool for the evaluation of cardiomyopathies, providing highly accurate information on the macroscopic changes of cardiac morphology, function, and tissue composition. For myocardial tissue characterization, the technique of myocardial delayed enhancement is a potentially promising tool for diagnosis, management, and prognosis. Several CMR approaches are now available to better diagnose and prognosticate dilated cardiomyopathy, hypertrophic cardiomyopathy, restrictive cardiomyopathy, arrhythmogenic right ventricular disease, myocarditis, and other cardiomyopathies.

Do patients with right ventricular outflow tract ventricular arrhythmias have a normal right ventricular wall motion? A quantitative analysis compared to normal subjects

BACKGROUND/AIM

Patients with ventricular ectopy from the right ventricular (RV) outflow tract (RVOT) are often referred for RV angiography to exclude disorders such as arrhythmogenic RV cardiomyopathy/dysplasia (ARVC/D). This is usually based on a qualitative assessment of the wall motion. We present a method to quantify the wall motion and to apply this method to compare patients with RVOT ectopy to normal subjects.

METHODS

RV angiograms were analyzed from 19 normal subjects and 11 subjects with RVOT ventricular arrhythmias (RVOT arrhythmia subjects) who had no other clinical or other evidence for ARVC/D. By a newly developed computer-based method, RV contours were first traced from multiple frames spanning the entire cardiac cycle. The fractional change in area between contours was then calculated as a serial function of time and location to determine both total contour area change and timing of contour movement. Contour area strain, defined as the differential change in area between nearby regions, was also computed.

RESULTS

The contour area change was greatest in the tricuspid valve region and least in the RVOT and midanterior regions. The onset of contraction was earliest in the RVOT region and latest in the apical, inferior, inferoapical, and subtricuspid valve regions. The contour strain was largest in superior tricuspid valve and inferior wall and near zero within the lateral tricuspid valve region. There were significant pairwise differences in contraction area, timing, and strain in the various regions. There were no significant differences between normal subjects and RVOT arrhythmia subjects.

CONCLUSIONS

The RV wall motion is nonuniform in contour area change, strain, and timing of motion. Patients with RVOT ventricular ectopy demonstrate wall motion parameters similar to those of normal subjects. This technique should be applicable in analyzing RV wall motion in patients suspected of having ARVC/D.

Rapid full volume data acquisition by real-time 3-dimensional echocardiography for assessment of left ventricular indexes in children: A validation study compared with magnetic resonance imaging

OBJECTIVE

We sought to assess the feasibility, accuracy, and reproducibility of a rapid full volume acquisition strategy using real-time (RT) 3-dimensional (3D) echocardiography (3DE) for measurement of left ventricular (LV) volumes, mass, stroke volume (SV), and ejection fraction (EF) in children.

METHODS

A total of 19 healthy children (mean 10.6 +/- 2.8 years, 11 male and 9 female) were prospectively enrolled in this study. RT 3DE was performed using an ultrasound system to acquire full volume 3D dataset from the apical window with electrocardiographic triggering in 8 s/dataset. The images were processed offline using software. The LV endocardial and epicardial borders were traced manually to derive LV end-systolic volume, end-diastolic volume, mass, SV, and EF. Magnetic resonance imaging (MRI) studies were performed on a 1.5-T scanner using a breath hold 2-dimensional cine-FIESTA (fast imaging employing steady-state acquisition) sequence.

RESULTS

All RT 3DE and MRI data were acquired successfully for analysis. Measurements of LV end-systolic volume, end-diastolic volume, mass, SV, and EF by RT 3DE correlated well by Pearson regression ( r = 0.86-0.97, P < .001) and agreed well by Bland-Altman analysis with MRI. The interobserver and intraobserver variability of RT 3DE measurements were less than 5%.

CONCLUSIONS

This prospective study demonstrated that RT 3DE measurements of LV end-systolic volume, end-diastolic volume, mass, SV, and EF in children using rapid full volume acquisition strategy are feasible, accurate, and reproducible and are comparable with MRI measurements.

Optimal timing for pulmonary valve replacement in adults after tetralogy of Fallot repair

The timing of pulmonary valve replacement in adult patients with repaired tetralogy of Fallot remains controversial. A magnetic resonance imaging study in 17 adult patients with repaired tetralogy of Fallot reveals a statistically significant decrease in right ventricular (RV) volume (RV end-diastolic volume 163 +/- 34 to 107 +/- 26 ml/m2, p <0.001; RV end-systolic volume 109 +/- 27 to 69 +/- 22 ml/m2, p <0.001) at a mean follow-up of 21 months after pulmonary valve replacement; whereas RV systolic function remained unchanged (mean RV ejection fraction 32 +/- 7% to 34 +/- 10%, p = 0.12). In no patients with a RV end-diastolic volume >170 ml/m2 or a RV end-systolic volume >85 ml/m2 before pulmonary valve replacement were RV volumes "normalized" after surgery.

Cardiac functional analysis with multi-detector row CT and segmental reconstruction algorithm: comparison with echocardiography, SPECT, and MR imaging

PURPOSE

To evaluate accuracy of cardiac functional analysis with multi-detector row computed tomography (CT) and segmental reconstruction algorithm over a range of heart rates.

MATERIALS AND METHODS

Institutional review board approval was obtained. Informed consent was not required. Multi-detector row CT (500-msec rotation time, 8 x 1-mm detector collimation) and magnetic resonance (MR) imaging were performed in 50 patients (28 men, 22 women; age range, 46-84 years; mean age, 67 years). Two-dimensional echocardiography was performed in 41 patients, and electrocardiographically (ECG)-gated single photon emission computed tomography (SPECT) was performed in 27. End-diastolic volume (EDV), end-systolic volume (ESV), ejection fraction (EF), and left ventricular (LV) mass were estimated with multi-detector row CT and compared with values estimated with MR imaging, which served as the reference standard. Additionally, EF values estimated with multi-detector row CT, echocardiography, and SPECT were compared with those estimated with MR imaging. Systemic error and degree of agreement of global functional parameters measured with MR imaging and other modalities were assessed. In a second analysis, linear regression analysis was added.

RESULTS

EF estimated with multi-detector row CT agreed and correlated well with EF estimated with MR imaging (bias +/- standard deviation, -1.2% +/- 4.6; r = 0.96). Agreement and correlation were similar for EDV (-0.35 mL +/- 15.2; r = 0.97), ESV (1.1 mL +/- 8.6; r = 0.99), and LV mass (2.5 mL +/- 15.0; r = 0.96). Standard deviation of EF difference between multi-detector row CT and MR imaging was significantly less than that between echocardiography and MR imaging (P < .001) or that between SPECT and MR imaging (P < .001).

CONCLUSION

Various LV functional parameters were measured with multi-detector row CT with a segmental approach, and measurements correlated and agreed with those obtained with MR imaging. Moreover, functional analysis with multi-detector row CT was more accurate than that with two-dimensional echocardiography or ECG-gated SPECT.

Assessment of Left Ventricular Parameters Using 16-MDCT and New Software for Endocardial and Epicardial Border Delineation

OBJECTIVE

The purpose of our study was to quantify left ventricular function and mass derived from retrospectively ECG-gated 16-MDCT coronary angiography data sets using a new analysis software based on automatic contour detection in comparison to corresponding standard of reference measurements acquired with MRI.

SUBJECTS AND METHODS

Multiplanar reformations in the short-axis orientation were calculated from axial contrast-enhanced CT images in 18 patients (men, 15; women, three; age range, 38-70 years; mean, 57.4 +/- 10.2 [SD] years) who were referred for CT coronary angiography. End-diastolic volume (EDV), end-systolic volume (ESV), ejection fraction (EF), and left ventricular mass (LVM) were analyzed with a recently developed imaging software using an automated contour detection algorithm of left ventricular endo- and epicardial contours and by manual tracing. The data were compared with similar measurements on MRI as the standard of reference.

RESULTS

EDV, ESV, EF, and LVM derived from an automated contour detection algorithm were not statistically significantly different from manual tracing (CT(auto) vs CT(manual): EDV = 137.1 +/- 45.7 mL vs 134.2 +/- 39.9 mL, ESV = 58.8 +/- 34.2 mL vs 58.1 +/-30.1 mL, EF = 59.2% +/- 13.7% vs 58.1% +/- 12.0%, LVM = 130.9 +/- 29.1 g vs 133.7 +/- 33.2 g; p > 0.05). However, EDV (118.7 +/- 43.6 mL), ESV (50.1 +/- 33.5 mL), and LVM (142.8 +/-38.4 g) as calculated on MR data sets were statistically significantly different from those calculated on CT (p < 0.05), whereas MRI-based EF (59.9% +/- 14.4%) did not differ statistically significantly from those based on both CT algorithms (p > 0.05).

CONCLUSION

Automatic and manual analysis of data acquired during CT coronary angiography using a 16-MDCT scanner allows a reliable assessment of left ventricular ejection fraction and a rough estimation of left ventricular volumes and mass.

Use of novel nonfluoroscopic three-dimensional electroanatomic mapping system to monitor and analyze heart surgery in animal models

BACKGROUND

The new method of three-dimensional (3D) electroanatomic mapping was presented as an important tool for cardiac imaging and intervention. We present herein the first use of this technology for the monitoring, analysis, and development of cardiac surgery at the preclinical stage.

METHODS

The method is based on utilizing a locatable catheter connected to an endocardial mapping and navigating system, to accurately establish the location and orientation of the tip of the mapping catheter and simultaneously record its local electrogram. The 3D geometry of the beating cardiac chamber is reconstructed in real time. The system was tested on six goats that underwent dynamic cardiomyoplasty. Two maps of each animal were performed: preoperative and postoperative during the stimulation protocol of the skeletal muscle.

RESULTS

The electroanatomic mapping system provided detailed maps of the left ventricle during the stimulation protocol, which demonstrated a striking geometric difference between the assisted and the unassisted beats. These geometric changes are best described by referring to left ventricular long-axis movements (22.3 +/- 3.8 degrees vs 3.4 +/- 1.6 degrees, p < 0.001), center-of-mass movements (10.4 +/- 3.0 mm vs 3.9 +/- 1.6 mm, p < 0.005), and the changes in upward movement viewed along the base (7.9 +/- 1.9 mm vs 3.6 +/- 1.7 mm, p < 0.01), middle (13.8 +/- 4.0 mm vs 7.3 +/- 1.8 mm, p < 0.005), and the apex of the heart (28.1 +/- 4.5 vs 5.3 +/- 2.3 mm, p < 0.001) [mean +/- SD].

CONCLUSIONS

The 3D electroanatomic mapping system allows detailed reconstruction of the left ventricular geometry and a clear view of the difference between the assisted and the unassisted beats. This novel monitoring system may serve as an important tool for the analysis and development of new techniques in cardiac surgery.

Measurement of left ventricular volumes and ejection fraction by quantitative gated SPET, contrast ventriculography and magnetic resonance imaging: a meta-analysis

All previous validation studies of quantitative gated single-photon emission tomography (QGS) have examined relatively few patients, and the accuracy of QGS thus remains uncertain. We performed a meta-analysis of data from 301 participants in ten studies that compared QGS using technetium-99m-labelled tracers with contrast left ventriculography (LVG), and from 112 participants in six studies that compared QGS with magnetic resonance imaging (MRI). Linear regression and Bland-Altman analyses were used to evaluate pooled data from individuals across the studies. The correlation between QGS and LVG for end-diastolic volume (EDV) (r=0.81, SEE=27 ml), end-systolic volume (ESV) (r=0.83, SEE=18 ml) and ejection fraction (EF) (r=0.79, SEE=8.3%) was good, as was that between QGS and MRI for EDV (r=0.87, SEE=34 ml), ESV (r=0.89, SEE=27 ml) and EF (r=0.88, SEE=7.2%). However, Bland-Altman plots indicated that LVG minus QGS differences for EDV generated a systematic and random error of 32+/-58 ml (mean+/-2SD), and that MRI minus QGS generated an error of 13+/-73 ml. In the subgroup of patients in whom ECG gating was set at eight intervals, QGS significantly underestimated EF by 7.6%+/-17.4% (mean+/-2SD) compared with LVG and by 6.3%+/-14.6% compared with MRI; no such underestimation was observed in the subgroup in whom ECG gating was set at 16 intervals. We conclude that in patients with ECG gating set at eight intervals, QGS systematically underestimates LV volumes and EF compared with both LVG and MRI. Since QGS also shows considerable variations around the systematic deviations, there remains uncertainty over whether an individual value determined with QGS approximates the true LV volumes and EF.

Feedback-assisted three-dimensional reconstruction of the left ventricle with MRI

PURPOSE

To develop and test a new technique for rapid, accurate three-dimensional (3D) reconstruction of the left ventricle (LV) and calculation of its volume parameters, with images from multiple orientations and interactive feedback.

MATERIALS AND METHODS

The ventricular surface was fit to a number of user-placed guide points in magnetic resonance (MR) images using bivariate smoothing splines. A 3D model was reconstructed and the LV volumes were calculated at both end diastole (ED) and end systole (ES). This technique was validated using a phantom, and applied to studies of 18 patients and four volunteers (N = 22) imaged on a 1.5-T clinical scanner. The results of the 3D method were compared to the standard 2D short-axis slice summation technique, which is widely used for the analysis of cardiac function.

RESULTS

There was excellent agreement between the computed volume of the phantom using the 3D modeling method and the actual volume (190.50 mL +/- 3.06 mL, and 191.0 mL +/- 2.5 mL, respectively). There was good correlation between the volumes calculated with our 3D model and the slice summation technique (ED volume (EDV) difference, 6.36% +/- 8.99% [mean +/- SD]; ES volume (ESV), 0.92% +/- 14.75%; stroke volume (SV), 10.54% +/- 13.95%; ejection fraction (EF), 4.22% +/- 9.16%). The 3D method was found to be more accurate than the slice summation technique for calculating LV volumes and mass from images of different slice orientations. Variations in the parameters between the two separate orientations using the 3D model vs. the slice summation method were as follows: EDV: 2.11% +/- 1.52% vs. 10.36% +/- 9.33%; ES volume: 2.76% +/- 1.64% vs. 6.39% +/- 3.62%; SV, 3.02% +/- 4.38% vs. 18.84% +/- 15.30%; EF, 2.03% +/- 2.16% vs. 8.58% +/- 6.73%; and LV mass: 4.77% +/- 2.41% vs. 24.59% +/- 6.41%. Differences in the ES volume due to the inclusion or exclusion of the most basal slice were found to be lower with the 3D model (6.90% +/- 3.83%) compared to the slice summation method (25.04% +/- 6.15%).

CONCLUSION

3D models can be used to accurately determine ventricular volume parameters. Results can be obtained using images from a variety of orientations, providing greater flexibility during image acquisition and possibly reducing the number of images needed for analysis. Feedback is provided to assist the analysis by providing a continuous update of the LV shape and volume. This feature allows the user to determine LV parameters to a predefined accuracy or to terminate the analysis when the parameters are not changing. This method is not restricted to multislice cine imaging in a single or prescribed slice orientation, and can be used for quick, accurate, and interactive analysis of cardiac function.

Three-dimensional echocardiographic determination of cardiac output at rest and under dobutamine stress: comparison with thermodilution measurements in the ischemic pig model

Determination of cardiac output is a potentially important clinical application of three-dimensional (3-D) echocardiography since it could replace invasive measurements with the Swan-Ganz-catheter. To date, there are no studies available to determine whether cardiac output measured by thermodilution can be predicted reliably under changing hemodynamic conditions. Fifteen pigs with ischemic myocardium were examined under four hemodynamic conditions at rest and under pharmacological stress with 5, 10, and 20 microg/kg/min dobutamine. The 3-D datasets were recorded by means of transesophageal echocardiography. The endocardial definition was enhanced by administering the contrast agent FS069 (Optison). Cardiac output was calculated as the product of stroke volume (end-diastolic - end-systolic volume) and heart rate. The invasive measurements were performed with a continuous thermodilution system. In general, there was moderate correlation between 3-D echocardiography and thermodilution(r = 0.72, P < 0.001). At rest, the 3-D echocardiographic measurements were slightly but significantly lower than the invasive measurements (mean difference 0.6 +/- 0.5L/min,P < 0.001). Under stress with 5, 10, and 20 microg/kg/min dobutamine, there was a marked increase in the deviation (1.3 +/- 0.5L/min,P < 0.001; 1.6 +/- 0.7 L/min,P < 0.001; and 2.1 +/- 1.1L/min,P < 0.001, respectively). The deviation was based on two factors: (1). Under stress, the decreasing number of frames per cardiac cycle acquired with 3-D echocardiography led to imprecise recording of end-diastolic and end-systolic volumes, and thus to an underestimation of cardiac output. At least 30 frames per cardiac cycle are needed to eliminate this effect. (2). There is a systematic difference between 3-D echocardiographic and invasive measurements, which is independent of the imaging rate. This is based on an overestimation of the true values by thermodilution. In conclusion, cardiac output can be determined correctly by 3-D echocardiography for normal heart rates at rest. At elevated heart rates, the temporal resolution of 3-D systems currently available is not adequate for reliable determination. In performing and evaluating future clinical comparative studies, the systematic difference between 3-D echocardiography and thermodilution, based on overestimation by thermodilution, must be taken into account.

Evaluation of methods for MR imaging of human right ventricular heart volumes and mass

PURPOSE

To assess the utility of two different imaging directions in the evaluation of human right ventricular (RV) heart volumes and mass with MR imaging; to compare breath-hold vs. non-breath-hold imaging in volume analysis; and to compare turbo inversion recovery imaging (TIR) with gradient echo imaging in RV mass measurement.

MATERIAL AND METHODS

We examined 12 healthy volunteers (age 27-59 years). Breath-hold gradient echo MR imaging was performed in two imaging planes: 1) perpendicular to the RV inflow tract (RVIT view), and 2) in the transaxial view (TA view). The imaging was repeated in the TA view while the subjects were breathing freely. To analyze RV mass using TIR images, the RV was again imaged at end-diastole using the two views. The RV end-diastolic cavity (RVEDV) and muscle volume as well as end-systolic cavity volume (RVESV) were determined with the method of discs. All measurements were done blindly twice to assess repeatability of image analysis. To assess reproducibility of the measurements, 6 of the subjects were imaged twice at an interval of 5-9 weeks.

RESULTS

RVEDV averaged 133.2 ml, RVESV 61.5 ml and the RVmass 46.2 g in the RVIT view and 119.9 ml, 56.9 ml and 38.3 g in the TA view, respectively. The volumes obtained with breath-holding were slightly but not significantly smaller than the volumes obtained during normal breathing. There were no marked differences in the RV muscle mass obtained with gradient echo imaging compared to TIR imaging in either views. Repeatability of volume analysis was better in TA than RVIT view: the mean differences were 0.7 +/- 4.0 ml and - 5.4 +/- 14.0 ml in end-diastole and 1.6 +/- 3.1 ml and - 1.5 +/- 13.9 ml in end-systole, respectively. Repeatability of mass analysis was good in both TIR and cine images in the RVIT view but slightly better in TIR images: - 0.5 +/ -2.4 g compared to 0.8 +/- 2.9 g in cine images. Reproducibility of imaging was good, mean differences for RVEDV and RVESV were -1.0 +/- 4.8 ml and -0.8 +/- 2.8 ml, respectively. Mean difference for RVmass was -0.9 +/- 2.6 g.

CONCLUSION

The present study suggests that gradient echo MR imaging is well applicable to RV volume and mass measurements. The best imaging plane for volumetric analysis seems to be the TA plane and there was no significant difference between breath-hold and conventional imaging. To assess RV mass, we recommend RVIT view; the TIR sequence quickly produced images of better quality compared to gradient echo images but no significant difference between masses was found and repeatability of analysis was equally good with both methods.

Cardiac MRI: recent progress and continued challenges

Cardiac MRI continues to develop and advance. MRI accurately depicts cardiac structure, function, perfusion, and myocardial viability with an overall capacity unmatched by any other single imaging modality. MRI is an accepted and widely utilized tool for cardiovascular research. Its clinical use has been limited, but is increasing because of its proven clinical efficacy, the proliferation of cardiac-capable MRI systems, and the development of improved pulse sequences. The following article reviews the landmark developments in this field, with an emphasis on recent progress in the evaluation of ischemic or acquired heart disease.

Four-dimensional reconstruction of the left ventricle using a fast rotating classical phased array scan head: preliminary results

The evaluation of left ventricular function by noninvasive methods is still a major problem in cardiology. Two-dimensional echocardiography requires mental reconstruction of the heart by the physician and is always based on approximation of heart shapes and volumes. Three-dimensional echocardiography is promising but has rhythmic and function constraints because of the acquisition during many cardiac cycles. This article reports a study carried out to validate a new 4-dimensional echocardiography method. With the use of a classical phased-array sensor with a fast rotating motorized motion and a standard ultrasound system, many slices at different angulations are obtained in a single cardiac cycle. After manual endocardial delineation and computation, a representation of the left ventricle (beating heart) and a volume quantification are obtained at each instant of the cardiac cycle. This method has been tested on 11 healthy volunteers and the results are in agreement with those obtained with standard 2-dimensional echocardiography. Because of its simplicity of operation and short time acquisition, this new imaging modality is highly valuable in left ventricle evaluation, even if further studies on pathologic hearts need to be performed.

In vitro determination of cardiac ventricular volumes using MRI at 1.0 T in a porcine heart model

PURPOSE

To determine the accuracy of a 1.0 T MR system with a standard gradient system for quantification of left and right ventricular volumes. A porcine heart model in vitro was used.

METHODS

In eight explanted porcine hearts the atria were removed and the aorta and the pulmonary truncus were cannulated. Defined volumes were injected into the ventricles. Magnetic resonance imaging (MRI): FFE-EPI (Multishot EPI) was used. Papillary muscles and trabeculae were excluded. True volumes and MR measurements were analysed separately for both ventricles and by both investigators.

RESULTS

The correlation of the true volumes and MR measurements was >0.99. MRI was found to be investigator independent in assessing right and left ventricular volumes in vitro.

CONCLUSIONS

MRI at 1.0 T using standard equipment can be used to quantitate cardiac ventricular volumes in vitro with high accuracy.

MR evaluation of ventricular function: true fast imaging with steady-state precession versus fast low-angle shot cine MR imaging: feasibility study

Short- and long-axis cine magnetic resonance (MR) images were obtained with a standard fast low-angle shot, or FLASH, sequence and a first-generation true fast imaging with steady-state precession (FISP) sequence on a 1.5-T MR imager. Contrast-to-noise ratios and volumetric left ventricular measurements were compared for manual and automatic segmentation. True FISP images were associated with significantly (P<.01) higher contrast-to-noise ratios and allowed better detection of the endocardial border. True FISP images were provided with short acquisition times and excellent contrast between the myocardium and the ventricular lumen.

A simple single slice method for measurement of left and right ventricular enlargement by electron beam tomography

RATIONALE AND OBJECTIVE

We devised to test the feasibility of measuring the left and right ventricular sizes by non-contrast electron beam tomographic images.

METHODS

Ventricular sizes consist of the sum of the intracavitary cavity and myocardial mass for each ventricle. A total of 50-image studies from subjects undergoing contrast-enhanced studies were used to develop the measurement methodology. About 20 contrast studies were used to test the measure. The methodology was then prospectively tested on 75 patients with non-contrast studies to estimate the intra-observer, inter-observer and inter-study reproducibility.

RESULTS

Multiple linear regression analysis was completed and the correct regression formulas to calculate ventricular volumes were acquired by using the area and span from the contrast studies. There was excellent correlation between the estimate of LV (r > 0.97, p < 0.001) and RV (r > 0.93, p < 0.001) sizes between measured and calculated (contrast, single slice) left and right ventricular volumes. The intra-observer, inter-observer and inter-study reproducibility demonstrated excellent results with < 7% difference in absolute values and a high correlation (r > 0.89, p < 0.001).

CONCLUSION

We conclude that the left and right ventricular sizes can be accurately estimated from a single mid-ventricular slice on non-contrast electron beam tomographic images.

Volumetric analysis of the right ventricle in children with congenital heart defects: comparison of biplane angiography and transthoracic 3-dimensional echocardiography

BACKGROUND

Three-dimensional echocardiography is a non-invasive imaging technique. The fact that it permits volumetric analyses independently of geometrical assumptions makes it a putatively useful method for the precise measurement of the volumes of the irregularly shaped right ventricles in children. The aim of this study was to assess the feasibility of this method and its agreement with angiocardiography based estimates of right ventricular volume in children with congenital heart disease.

METHODS

We studied 102 children with congenital heart disease. The angiocardiographic right ventricular volumetry was performed using a biplanar technique using Simpson's rule and corrected with Lange's correction factors. The echo data sets were registered trans-thoracically with a rotating transmitter. Volumes were calculated after manual planimetry by adding the volumes of the individual slices.

RESULTS

Calculation of right ventricular volume echocardiographically was possible only in 34% of patients, mostly infants and toddlers. In comparison to angiocardiography, the measured volumes were 1.1 +/- 6.9 ml (19.5 +/- 34.1%) or 6.3 +/- 9.4 ml (42.5 +/- 33.6%) smaller during systole or diastole, respectively. The limits of agreement were -12.5 and 13.6 ml, or 12.45 and 25.15 ml during systole or diastole, respectively. When plotted to a logarithmical scale, the correlation coefficients r2 were 0.70 for systolic and 0.79 for diastolic measurements.

CONCLUSION

Transthoracic 3-dimensional echocardiography with a rotating transmitter is feasible for volumetry only in small children. The volumes measured were significantly smaller than the ones calculated from the angiocardiographic images. The correlation between the two methods is moderate.