Health & Medical Cardiovascular Health

Correction of 3D Echocardiography Needed for RV Assessment

Correction of 3D Echocardiography Needed for RV Assessment

Abstract and Introduction

Abstract


Background: Three-dimensional echocardiography (3DE) and semi-automatic right ventricular delineation has been proposed as an appropriate method for right ventricle (RV) evaluation. We aimed to examine how manual correction of semi-automatic delineation influences the accuracy of 3DE for RV volumes and function in a clinical adult setting using cardiac magnetic resonance (CMR) as the reference method. We also examined the feasibility of RV visualization with 3DE.
Methods: 62 non-selected patients were examined with 3DE (Sonos 7500 and iE33) and with CMR (1.5T). Endocardial RV contours of 3DE-images were semi-automatically assessed and manually corrected in all patients. End-diastolic (EDV), end-systolic (ESV) volumes, stroke volume (SV) and ejection fraction (EF) were computed.
Results: 53 patients (85%) had 3DE-images feasible for examination. Correlation coefficients and Bland Altman biases between 3DE with manual correction and CMR were r = 0.78, −22 ± 27 mL for EDV, r = 0.83, −7 ± 16 mL for ESV, r = 0.60, −12 ± 18 mL for SV and r = 0.60, −2 ± 8% for EF (p < 0.001 for all r-values). Without manual correction r-values were 0.77, 0.77, 0.70 and 0.49 for EDV, ESV, SV and EF, respectively (p < 0.001 for all r-values) and biases were larger for EDV, SV and EF (-32 ± 26 mL, −21 ± 15 mL and −6 ± 9%, p ≤ 0.01 for all) compared to manual correction.
Conclusion: Manual correction of the 3DE semi-automatic RV delineation decreases the bias and is needed for acceptable clinical accuracy. 3DE is highly feasible for visualizing the RV in an adult clinical setting.

Introduction


Assessment of the right ventricular volumes and function is of great importance in the diagnosis of various heart diseases e.g. pulmonary hypertension and congenital heart disease for the choice of therapeutical strategies and not least of prognostic value.

Two-dimensional echocardiography (2DE) is the most commonly used clinical imaging modality in the evaluation of the right ventricle (RV). The complex geometrical structure of the RV with both a crescent shape and an outspread inflow and outflow tract requires a combination of several different scan planes for estimation of size and function with 2DE. M-Mode and tissue Doppler imaging of the free lateral wall of the RV are measurements in one point and are used as surrogates for the RV function. Hence, current echocardiographic techniques are not suitable for calculating right ventricular volumes and function accurately with a simple algorithm.

Cardiac magnetic resonance imaging (CMR) is currently the gold standard for quantification and monitoring volumes and function of the RV. However CMR is not available at all centres, the equipment is expensive and bedside acquisition is not possible. Some patients cannot undergo CMR because of claustrophobia or implants such as pacemakers and implantable defibrillators (ICD), even if some implanted cardiac devices is becoming a relative contraindication for CMR.

Three-dimensional echocardiography (3DE) potentially offers a full volume assessment of the RV overcoming the complex geometry problem. Various algorithms have been applied to assess the RV with 3DE, such as multiple planes around the same centreline, and parallel multislicing leaving room for interpolation among planes and slices. Recent studies have used a new tool for RV volume rendering with a semi-automatic dedicated algorithm. The main focus has been patients with congenital heart disease and young healthy adult populations. Adult patients with acquired heart disease were recently evaluated with the semi-automatic dedicated 3DE algorithm. Some investigators have manually corrected the semi-automatic delineation in all patients, some not at all and some if considered necessary. Thus, it is not clear if manual correction is needed for clinical use of 3DE.

Therefore, our study was designed to assess how manual correction of the semi-automatic delineation with 3DE influences the accuracy of RV volumetric and functional measurements compared to CMR in a clinical setting with a wide range of adult patients. We also examined the feasibility of visualizing the RV.

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