Right ventricular volumes and ejection fraction with fast cine MR imaging in breath-hold technique: applicability, normal values from 52 volunteers, and evaluation of 325 adult cardiac patients

Impact of Pulmonary Arterial Elastance on Right Ventricular Mechanics and Exercise Capacity in Repaired Tetralogy of Fallot

BACKGROUND AND OBJECTIVES

Pathophysiological changes of right ventricle (RV) after repair of tetralogy of Fallot (TOF) are coupled with a highly compliant low-pressure pulmonary artery (PA) system. This study aimed to determine whether pulmonary vascular function was associated with RV parameters and exercise capacity, and its impact on RV remodeling after pulmonary valve replacement.

METHODS

In a total of 48 patients over 18 years of age with repaired TOF, pulmonary arterial elastance (Ea), RV volume data, and RV-PA coupling ratio were calculated and analyzed in relation to exercise capacity.

RESULTS

Patients with a low Ea showed a more severe pulmonary regurgitation volume index, greater RV end-diastolic volume index, and greater effective RV stroke volume (p=0.039, p=0.013, and p=0.011, respectively). Patients with a high Ea had lower exercise capacity than those with a low Ea (peak oxygen consumption [peak VO₂] rate: 25.8±7.7 vs. 34.3±5.5 mL/kg/min, respectively, p=0.003), while peak VO₂ was inversely correlated with Ea and mean PA pressure (p=0.004 and p=0.004, respectively). In the univariate analysis, a higher preoperative RV end-diastolic volume index and RV end-systolic volume index, left ventricular end-systolic volume index, and higher RV-PA coupling ratio were risk factors for suboptimal outcomes. Preoperative RV volume and RV-PA coupling ratio reflecting the adaptive PA system response are important factors in optimal postoperative results.

CONCLUSIONS

We found that PA vascular dysfunction, presenting as elevated Ea in TOF, may contribute to exercise intolerance. However, Ea was inversely correlated with pulmonary regurgitation (PR) severity, which may prevent PR, RV dilatation, and left ventricular dilatation in the absence of significant pulmonary stenosis.

Phantom-Less Nonlinear Magnetic Resonance Imaging Calibration With Multiple Input Blood Flow Model

PURPOSE

Previous work used phantoms to calibrate the nonlinear relationship between the gadolinium contrast concentration and the intensity of the magnetic resonance imaging signal. This work proposes a new nonlinear calibration procedure without phantoms and considers the variation of contrast agent mass minimum combined with the multiple input blood flow system. This also proposes a new single-input method with meaningful variables that is not influenced by reperfusion or noise generated by aliasing. The reperfusion in the lung is usually neglected and is not considered by the indicator dilution method. However, in cases of lung cancer, reperfusion cannot be neglected. A new multiple input method is formulated, and the contribution of the pulmonary artery and bronchial artery to lung perfusion can be considered and evaluated separately.

METHODS

The calibration procedure applies the minimum variation of contrast agent mass in 3 different regions: (1) pulmonary artery, (2) left atrium, and (3) aorta. It was compared with four dimensional computerized tomography with iodine, which has a very high proportional relationship between contrast agent concentration and signal intensity.

RESULTS

Nonlinear calibration was performed without phantoms, and it is in the range of phantom calibration. It successfully separated the contributions of the pulmonary and bronchial arteries. The proposed multiple input method was verified in 6 subjects with lung cancer, and perfusion from the bronchial artery, rich in oxygen, was identified as very high in the cancer region.

CONCLUSIONS

Nonlinear calibration of the contrast agent without phantoms is possible. Separate contributions of the pulmonary artery and aorta can be determined.

High-echoic line tracing of transthoracic echocardiography accurately assesses right ventricular enlargement in adult patients with atrial septal defect

Accurate measurement of right ventricular (RV) size using transthoracic echocardiography (TTE) is important for evaluating the severity of congenital heart diseases. The RV end-diastolic area index (RVEDAi) determined using TTE is used to assess RV dilatation; however, the tracing line of the RVEDAi has not been clearly defined by the guidelines. This study aimed to determine the exact tracing method for RVEDAi using TTE. We retrospectively studied 107 patients with atrial septal defects who underwent cardiac magnetic resonance imaging (CMR) and TTE. We measured the RVEDAi according to isoechoic and high-echoic lines, and compared it with the RVEDAi measured using CMR. The isoechoic line was defined as the isoechoic endocardial border of the RV free wall, whereas the high-echoic line was defined as the high-echoic endocardial border of the RV free wall more outside than the isoechoic line. RVEDAi measured using high-echoic line (high-RVEDAi) was more accurately related to RVEDAi measured using CMR than that measured using isoechoic line (iso-RVEDAi). The difference in the high-RVEDAi was 0.3 cm²/m², and the limit of agreement (LOA) was - 3.7 to 4.3 cm²/m². With regard to inter-observer variability, high-RVEDAi was superior to iso-RVEDAi. High-RVEDAi had greater agreement with CMR-RVEDAi than with iso-RVEDAi. High-RVEDAi can become the standard measurement of RV size using two-dimensional TTE.

The right ventricular involvement in dilated cardiomyopathy: prevalence and prognostic implications of the often-neglected child

Dilated cardiomyopathy (DCM) is a primary heart muscle disease characterized by left or biventricular systolic impairment. Historically, most of the clinical attention has been devoted to the evaluation of left ventricular function and morphology, while right ventricle (RV) has been for many years the forgotten chamber. Recently, progresses in cardiac imaging gave clinicians precious tools for the evaluation of RV, raising the awareness of the importance of biventricular assessment in DCM. Indeed, RV involvement is far from being uncommon in DCM, and the presence of right ventricular dysfunction (RVD) is one of the major negative prognostic determinants in DCM patients. However, some aspects such as the possible role of specific genetic mutations in determining the biventricular phenotype in DCM, or the lack of specific treatments able to primarily counteract RVD, still need research. In this review, we summarized the current knowledge on RV involvement in DCM, giving an overview on the epidemiology and pathogenetic mechanisms implicated in determining RVD. Furthermore, we discussed the imaging techniques to evaluate RV function and the role of RV failure in advanced heart failure.

Cardiac MRI predictors of adverse outcomes in adults with a systemic right ventricle

Aims

Predicting risk in individuals with a systemic right ventricle (SRV) remains difficult. We assessed the value of cardiac MRI (CMR) for predicting death, heart transplantation (HT), or need for a ventricular assist device (VAD) in adults with D‐transposition of the great arteries (DTGA) post Mustard/Senning and in adults with congenitally corrected transposition of the great arteries (ccTGA) at two large academic centres.

Methods and results

Between December 1999 and November 2020, 158 adult patients with an SRV underwent CMR. Indexed right ventricular end‐diastolic volume (RVEDVI), indexed right ventricular end‐systolic volume (RVESVI), right ventricular ejection fraction (RVEF), and right ventricular mass (RV mass) were determined by a core laboratory. Receiver operating curves, area under the curve (AUC), and cut‐points maximizing sensitivity and specificity for the endpoint for each CMR parameter were calculated. Over a median of 8.5 years, 21 patients (13%) met a combined endpoint of HT referral, VAD, or death. Each CMR parameter was significantly associated with the endpoint in both cohorts. The AUCs for RVEDVI, RVESVI, RVEF, and RV mass to predict the endpoint were 0.93, 0.90, 0.73, and 0.84 for DTGA and 0.76, 0.74, 0.71, and 0.74 for ccTGA, respectively. Optimized cut‐points for RVEDVI were calculated for DTGA and ccTGA and were 132 and 126 mL/m², respectively. RVEDVI cut‐points were simplified to 130 mL/m² for survival analysis, which was significantly associated with survival in both cohorts.

Conclusions

Cardiac MRI parameters are associated with an increased risk of death, HT, or VAD in patients with an SRV and should be considered to facilitate risk stratification.

Long-term outcomes of pulmonary valve replacement in patients with repaired tetralogy of Fallot

OBJECTIVES

The objectives of this study were to evaluate long-term outcomes of pulmonary valve replacement (PVR) in patients with repaired tetralogy of Fallot (TOF) and to identify the factors associated with adverse clinical events (ACEs).

METHODS

A total of 190 patients who underwent PVR between 1998 and 2015 after repair of TOF were retrospectively analysed. ACE was defined as all-cause death, heart transplantation or new-onset sustained arrhythmia. Univariable Cox proportional hazards regression analysis was used to identify the factors associated with ACE after PVR.

RESULTS

The median age at PVR was 19 years. Preoperative magnetic resonance imaging (MRI) was performed in 143 (75%) patients, and the median right ventricular (RV) end-diastolic and end-systolic volume index was 164 and 82 ml/m2, respectively. The follow-up completeness was 94%, and the median follow-up duration was 9.8 years. The transplantation-free survival and freedom from ACE at 15 years was 95% and 90%, respectively. The factors associated with ACE were older age at PVR, older age at TOF repair, New York Heart Association functional class III or IV, presence of tachyarrhythmias, longer cardiopulmonary bypass time and concomitant arrhythmia surgery. In a subgroup analysis of 143 patients with preoperative MRI data, larger RV end-systolic volume index, larger left ventricular end-systolic volume index and lower left ventricular ejection fraction were associated with ACE.

CONCLUSIONS

Long-term outcomes of PVR in patients with repaired TOF were satisfactory. Proactive PVR before the onset of advanced symptoms, tachyarrhythmias and ventricular dysfunction may further improve the long-term survival of this patient population.

Comparison of the early cardiac electromechanical remodeling following transcatheter and surgical secundum atrial septal defect closure in adults

Background

Secundum atrial septal defect (ASD) closure leads to electrical and mechanical remodeling that occurs early after shunt disappearance. The relationship between electromechanical remodeling using electrocardiogram (ECG) and cardiac magnetic resonance (CMR) after percutaneous and surgical closure has not yet been recorded in prospective studies.

Objective

We thought to study right atrium (RA) and right ventricle (RV) changes by CMR 3 months after transcatheter and surgical closure and their comparison with electrical remodeling by ECG.

Results

We prospectively evaluated 30 consecutive adult patients with isolated secundum ASD who were referred for (transcatheter and surgical) ASD closure.

There was significant reduction in all of the electrical parameters within the same group as compared to the baseline values, except P wave dispersion (Pd). (P max was 97.33 ± 16.67 (pre closure) to 76 ± 15.49 (post closure) in the device group and 97.33 ± 12.79 (preclosure) to 73.33 ± 16.32 (post closure) in the surgical group, QRS complex was 104 ± 18.82 (preclosure) to 80 ± 18.51 (post closure) in the device group and 106.67 ± 14.47 (preclosure) to 86.67 ± 17.99 (post closure) in the surgical group. QTc maximum was 478.53 ± 36.79 (preclosure) to 412.53 ± 38.03 (post closure) in the device group and 470.53 ± 65.70 (preclosure) to 405.93 ± 63.08 (post closure) in the surgical group, and QTc dispersion was 70.33 ± 24.04 (preclosure) to 60.26 ± 28.56 (post closure) in the device group and 80.73 ± 30.38 (preclosure) to 60.27 ± 28.57 (post closure) in the surgical group).There was no significant difference between two groups indicating that transcatheter and surgical closure had led to equivalent value of electrical remodeling.

In CMR study, we measured RA maximal volume and right ventricle end diastolic volume (RVEDV), RA maximal volume decreased significantly as compared to the base line values post closure in both groups (P value < 0.001). The reduction in RA max volume was more in the transcatheter closure group; however, this difference was not statistically significant when compared with the surgical arm (P value = 0.5).RVEDV decreased significantly in both groups as compared to the baseline values (P value < 0.001). Transcatheter closure resulted in more significant reduction in the RVEDV than the surgical closure (P value = 0.03).

Conclusion

Our study showed early significant electromechanical reverse remodeling in most of the study parameters from the baseline values after ASD closure. We found no significant differences in all of the electrical and RA mechanical remodeling parameters with significantly better mechanical remodeling of RV in the device group.

Determinants of QRS duration in patients with tetralogy of Fallot after pulmonary valve replacement

BACKGROUND

Following the repair of TOF patients may be left with pulmonary regurgitation and a dilated right ventricle (RV), which in turn can lead to ventricular arrhythmias and sudden death. A prolonged QRS is a predictor of ventricular arrhythmias. However, whether subsequent pulmonary valve replacement (PVR) can reverse QRS-prolongation is controversial. We hypothesized that changes in QRS duration following PVR are determined by preoperative QRS-duration and RV volumes METHODS: A retrospective single-center cohort study was conducted on 142 post-TOF repair patients (mean age 25 ± 13 years) who underwent PVR between 1995 and 2019. Information on QRS duration and RV volumes measured by cardiac MRI (available in 83 patients) were collected. A linear mixed model was used to investigate the association between the preoperative QRS duration and RV volumes and the postoperative QRS duration.

RESULTS

The QRS-duration following PVR continued to increase in all subjects with a prolonged preoperative QRS-duration(>160 ms, rate of increase of 0.87 msec ± 0.33 per year; p = .01), markedly raised RV end-diastolic volume (RVEDV; ≥166 ml/m2, rate of increase of 2.0 msec ± 0.37 per year; p < .01) or RV end-systolic volume (RVESV; ≥89 ml/m² , rate of increase of 1.25 msec ± 0.43 per year; p = .01). In contrast, in patients with preoperative QRS-duration <160 msec (p = .16), RVEDV <166 ml/m² (p = .14), or RVESV < 89 ml/m2 (p = .37), the QRS-duration did not change significantly when compared to preoperative values.

CONCLUSIONS

In subjects with shorter QRS and smaller RV volumes, QRS duration did not show further prolongation following PVR. While markedly prolonged QRS and increased RV volumes were associated with a small but constant increase in QRS duration despite PVR.

MRI Assessment of Right Ventricular Volumes and Function in Patients With Repaired Tetralogy of Fallot Using kat-ARC Accelerated Sequences

OBJECTIVE. The objective of our study was to assess the accuracy and reproducibility of right ventricular volumes and function measurements in patients with repaired tetralogy of Fallot using two k-adaptive-t autocalibrating reconstruction for cartesian sampling (kat-ARC) accelerated sequences: a morphologic 3D cine sequence and a functional free-breathing 4D flow sequence. SUBJECTS AND METHODS. Seventeen patients who underwent cardiac MRI with gadolinium injection as part of follow-up of repaired tetralogy of Fallot from March 2017 to July 2018 were prospectively included in the initial study population; the final study cohort was composed of 15 of the 17 patients. Ventricle volume measurements were performed on a 3D cine kat-ARC sequence, a 4D flow kat-ARC sequence, and a 2D cine balanced steady-state free precession (bSSFP) sequence. The 2D cine bSSFP sequence was the reference standard in cardiac assessment. Intertechnique and interobserver analyses were performed. Bland-Altman analysis and correlation tests were used to compare quantitative measurements. RESULTS. Ventricular end-diastolic volume (EDV) and end-systolic volume (ESV) values were well correlated in the right ventricle (r = 0.94-0.98) for both 3D and 4D sequences. Ejection fraction (EF) also showed good correlation for both 3D and 4D sequences (r = 0.79 and r = 0.92). Bland-Altman analysis showed good agreement between right and left ventricular volumes, with narrower limits of agreement in the left ventricle, and an intraclass correlation coefficient (ICC) of greater than 0.80. For the 4D flow sequence, ventricular volumes were overestimated, which led to underestimation of the EF (bias for EDV = -10.2 mL, bias for ESV = -22.7 mL, bias for EF = 6.4%). Interobserver agreement was excellent for the ventricular volumes (ICC, 0.93-0.99) and fair to excellent for the EFs (ICC, 0.59-0.83). CONCLUSION. Compared with the reference standard 2D bSSFP sequence, the 3D cine kat-ARC accelerated sequence showed good accuracy and reproducibility for right ventricular measurements in patients with repaired tetralogy of Fallot. The short duration of the 4D flow kat-ARC sequence appears promising for performing volumetric measurements.

Preoperative Threshold for Normalizing Right Ventricular Volume After Transcatheter Closure of Adult Atrial Septal Defect

BACKGROUND

The latest guidelines recommend early intervention in adult atrial septal defect (ASD) patients with signs of right ventricular (RV) enlargement. However, the criteria of RV enlargement for optimal intervention remain unclear. We investigated the preoperative determinants for normalizing the RV volume after transcatheter closure of ASD in adults.Methods and Results:We retrospectively analyzed 52 ASD patients who underwent transcatheter closure. Cardiac magnetic resonance imaging (CMR) measured RV volume before and 1 year after the closure. The patients were divided into normalized (postoperative RV end-systolic volume index [RVESVI] <47 mL/m²and end-diastolic volume index [RVEDVI] <108 mL/m²) and non-normalized (postoperative RVESVI ≥47 mL/m²or RVEDVI ≥108 mL/m²) groups. Preoperative RVESVI was significantly smaller (72 mL/m²vs. 80 mL/m²) and RVEF was higher (56% vs. 51%) in the normalized group compared with the non-normalized group. Receiver-operating characteristic analysis for the normalization of postoperative RV volume showed that the preoperative threshold value of RVESVI was 75 mL/m². In addition, multivariate analysis showed that preoperative RVESVI was an independent predictor for normalization of RV volume.

CONCLUSIONS

Preoperative RVESVI is an independent predictor for normalization of RV volume at 1 year after transcatheter closure of ASD in adults. Early intervention before RVESVI reaches 75 mL/m²may confer optimal timing for normalizing RV volume.

Levels of agreement between cardiac magnetic resonance and conductance catheter measurements of right ventricular volumes after pulmonary artery banding

BACKGROUND

Pressure-volume analysis is the gold standard for quantifying pump function of the right ventricle (RV); however, volume measurements based on a conductive catheter may be imprecise. The reference method for volume assessment is cardiac magnetic resonance (CMR).

PURPOSE

To determine the levels of agreement between RV volume measurements obtained by cine CMR, phase-contrast CMR (PC CMR), and a conductance catheter in an animal model.

MATERIAL AND METHODS

CMR was performed in 20 sheep three months after pulmonary artery banding. Ejection fraction (EF), end-diastolic (EDV), end-systolic (ESV), and stroke volumes (SV) were obtained by cine CMR and conductance catheter.

RESULTS

Statistically significant differences between cine CMR and conductance catheter derived volume measurements were found for EDV (P < 0.001), ESV (P < 0.05), and SV (P < 0.05). Bland-Altman analysis showed very poor agreement between the two methods: EDV, bias 36.27 mL, agreement of limits 1.96-70.57 mL; ESV, bias 15.33 mL, agreement of limits -6.89-37.55 mL; and SV, bias 20.69 mL, agreement of limits 8.01-49.10 mL. Good agreement was found for SV between cine CMR and PC CMR (bias -7.0 mL, agreement of limits -24.01-9.98 mL), while SV derived from PC CMR measurements showed poor agreement with conductance catheter (bias 27.76 mL, agreement of limits -3.84-59.26 mL).

CONCLUSION

Poor agreement between the conductance catheter and CMR RV volume measurements was found. PC CMR and cine CMR measurements of SV agreed well.

Utility of Doppler Echocardiography to Estimate the Severity of Pulmonary Valve Regurgitation Fraction in Patients with Repaired Tetralogy of Fallot

BACKGROUND

In patients with repaired Tetralogy of Fallot (rTOF), pulmonary regurgitation (PR) leads to significant morbidity. Cardiac magnetic resonance imaging (CMR) is the gold standard to assess severity of PR in rTOF patients. We compared Doppler echocardiography derived indices of PR with CMR to find the best predictive parameter for hemodynamically significant (hs) PR.

METHODS

This is a retrospective analysis of echocardiogram and CMR measurements. Doppler indices obtained included: PR deceleration slope, pressure half time (PHT) and PR index. Receiver operating characteristic curve analysis was used to optimize the sensitivity and specificity of selected variables in predicting hsPR. Inter-observer variability of the Doppler parameters was assessed in a random sample of 25 Doppler spectral recordings.

RESULTS

Our cohort (n = 96) comprised of 52 (54.2%) males. The mean (SD) age at CMR was 22.9 (10.3) years. 83.4% patients underwent complete repair with transannular patch. 78 (81%) patients had hsPR as defined by CMR PR > 20%. Doppler parameters with the values of; PR index of < 0.86, PR deceleration slope of > 375 cm/s² and a PHT < 130 ms, demonstrated high sensitivity (93%) and high negative predictive values (98-99%). All the Doppler indices demonstrated minimal inter-observer variability (PHT = 0.9, 95% CI 0.69-0.97; PRi = 0.95, 95%CI 0.83-0.98).

CONCLUSION

Our data, with its high negative predictive values, show that Doppler derived echocardiography indices have an ability to rule out hsPR, as measured by CMR. PHT, PR index and deceleration slope correlate with hsPR and can be used as screening tools for further testing.

Can 3D RVEF be Prognostic for the Non-Ischemic Cardiomyopathy Patient but not the Ischemic Cardiomyopathy Patient? A Cardiovascular MRI Study

Background: While left ventricular ejection fraction (LVEF) has been shown to have prognostic value in ischemic cardiomyopathy (ICMX) patients, right ventricular ejection fraction (RVEF) has not been systematically evaluated in either ICMX or non-ischemic cardiomyopathy (NICMX) patients. Moreover, an accurate estimation of RVEF is problematic due to the geometry of the right ventricle (RV). Over the years, there have been improvements in the resolution, image acquisition and post-processing software for cardiac magnetic resonance imaging (CMR), such that CMR has become the “gold standard” for measuring RV volumetrics and RVEF. We hypothesize that CMR defines RVEF more so than LVEF and might have prognostic capabilities in ischemic and non-ischemic cardiomyopathy patients (ICMX and NICMX). Methods: Patients that underwent CMR at our institution between January 2005 and October 2012 were retrospectively selected if three-dimensional (3D) LVEF < 35%. Patients were further divided into ICMX and NICMX groups. The electronic medical record (EMR) database inquiry determined all-cause mortality and major adverse cardiovascular events (MACE). Additionally, a Social Security Death Index (SSI) database inquiry was performed to determine all-cause mortality in patients who were lost to follow-up. Patients were further sub-grouped on the basis of 3D RVEF ≥ 20%. Separately, patients were sub-grouped by LVEF ≥ 20% in both ICMX and NICMX cases. A cut-off of ≥20% was chosen for the RVEF based on the results of prior studies showing significance based on Kaplan–Meier (KM) survival curves. Cumulative event rates were estimated for each subgroup using the KM analysis and were compared using the log-rank test. The 3D RV/LVEFs were compared to all-cause mortality and MACE. ICMX patients were defined using the World Health Organization (WHO) criteria. Results: From a 7000-patient CMR database, 753 heart failure patients were selected. Eighty-seven patients met WHO definition of ICMX and NICMX (43 ICMX and 44 NICMX). The study patients were followed for a median of 3 years (Interquartile range or IQR 1.5–6.5 years). The mean age of patients was 58 ± 13 years; 79% were male. In ICMX, mean 3D LVEF was 21% ± 6% and mean 3D RVEF was 38% ± 14%, while for NICMX, mean 3D LVEF was 16% ± 6% and mean 3D RVEF was 30% ± 14% (p < 0.005 for intra- and inter-group comparison). It should be noted that LVEF < RVEF in both groups and the ejection fraction (EF) in NICMX was less than the corresponding EF in ICMX. Overall mortality was higher in ICMX than NICMX (12/40, 30% vs. 7/43, 16%; p < 0.05). Patients were stratified based on both RVEF and LVEF with a threshold of EF ≥ 20% separately. RVEF but not LVEF was a significant predictor of death for NICMX (χ² = 8; p < 0.005), while LVEF did not predict death in ICMX (χ² = 2, p = not significant). Similarly, time to MACE was predicted by RVEF for NICMX (χ² = 9; p < 0.005) but not by LVEF in ICMX (χ² = 1; p = NS). Importantly, RVEF, while predictive of NICMX MACE, did not emerge as a predictor of survival or MACE in ICMX. Conclusions: Via 3D CMR in non-ischemic CMX patients, RVEF has important value in predicting death and time to first MACE while 3D LVEF is far less predictive.

Sex- and Age-Related Reference Values in Cardiology, with Annotations and Guidelines for Interpretation

The definition of "abnormal" in clinical sciences is often based on so-called reference values which point to a range that experts by some sort of consensus consider as normal when looking at biological variables. Such a level is commonly calculated by taking (twice) the standard deviation from the mean, or considering certain percentiles. The suspicion or even confirmation of a disease is then established by demonstrating that the value measured exceeds the upper or lower reference value. As is often the case, the measurement accuracy may depend on the conditions and specific method employed to collect and analyze data. This implies that, for example, data assessed by 2D echocardiography possibly differ from those obtained by MRI and therefore require modality-specific reference values. In this review we summarize reference values for the electrocardiogram, cardiac compartmental volumes, and arterial vessel size in males and females for various age groups. These values may further depend on other variables such as body size, physical training status, and ethnicity. Additional variables relevant for cardiology such as those referring to the microcirculation and biomarkers are only mentioned with reference to the pertinent literature. In general, the sex- and age-specific differences observed are often remarkable and warrant consideration in clinical practice and basic biomedical sciences.

Diagnostic value of Doppler echocardiography for identifying hemodynamic significant pulmonary valve regurgitation in tetralogy of Fallot: comparison with cardiac MRI

Quantification of pulmonary regurgitation (PR) is essential in the management of patients with repaired tetralogy of Fallot (TOF). We sought to evaluate the accuracy of first-line Doppler echocardiography in comparison with cardiac magnetic resonance imaging (MRI) to identify hemodynamic significant PR. Paired cardiac MRI and echocardiographic studies (n = 97) in patients with repaired TOF were retrospectively analyzed. Pressure half time (PHT) and pulmonary regurgitation index (PRi) were measured using continuous wave Doppler. The ratio of the color flow Doppler regurgitation jet width to pulmonary valve (PV) annulus (jet/annulus ratio) and diastolic to systolic time velocity integral (DSTVI; pulsed wave Doppler) were assessed. Accuracy of echocardiographic measurements was tested to identify significant PR as determined by phase-contrast MRI (PR fraction [PRF] ≥ 20%). Mean PRF was 29.4 ± 15.7%. PHT < 100 ms had a sensitivity of 93%, specificity 75%, positive predictive value (PPV) 92% and negative predictive value (NPV) 78% for identifying significant PR (C-statistic 0.82). PRi < 0.77 had sensitivity and specificity of 66% and 54%, respectively (C-statistic 0.63). Jet/annulus ratio ≥1/3 had sensitivity 96%, specificity 75%, PPV 92% and NPV 82% (C-statistic 0.87). DSTVI had sensitivity 84%, specificity 33%, PPV 84% and NPV 40%, (C-statistic 0.56). Combined jet/annulus ratio ≥1/3 and PHT < 100 ms was highly accurate in identifying PRF ≥ 20%, with sensitivity 97% and specificity 100%. PHT and jet/annulus ratio on Doppler echocardiography, especially when combined, are highly accurate in identifying significant PR and therefore seem useful in the follow-up of patients with repaired TOF.

Horizontal Long Axis Imaging Plane for Evaluation of Right Ventricular Function on Cardiac Magnetic Resonance Imaging

Purpose:

The purpose of this study was to evaluate a horizontal long axis (HLA) magnetic resonance imaging (MRI) plane aligned to the long axis of the right ventricular (RV) cavity for functional analysis by comparing the measurement variability and time required for the analysis with that using a short-axis (SAX) image orientation.

Materials and Methods:

Thirty-four cardiac MRI exams with cine balanced steady-state free precession image stacks in both the SAX and the HLA of the RV (RHLA) were evaluated. Two reviewers independently traced RV endocardial borders on each image of the cine stacks. The time required to complete each set of traces was recorded, and the RV end-diastolic volume, end-systolic volume, and ejection fraction were calculated. Analysis times and RV measurements were compared between the two orientations.

Results:

Analysis time for each reviewer was significantly shorter for the RHLA stack (reviewer 1 = 6.4 ± 1.8 min, reviewer 2 = 6.0 ± 3.3 min) than for the SAX stack (7.5 ± 2.1 and 6.9 ± 3.6 min, respectively; P < 0.002). Bland–Altman analysis revealed lower mean differences, limits of agreement, and coefficients of variation for RV measurements obtained with the RHLA stack.

Conclusions:

RV functional analysis using a RHLA stack resulted in shorter analysis times and lower measurement variability than for a SAX stack orientation.

Repaired tetralogy of Fallot with coexisting unrepaired partial anomalous pulmonary venous connection is associated with diminished right ventricular ejection fraction and more severe right ventricular dilation

BACKGROUND

There is an established association between tetralogy of Fallot and partial anomalous pulmonary venous connections. This association is important because surgically repaired tetralogy patients have increased risk of right heart failure. We hypothesize that partial anomalous venous connections increase right ventricular volumes and worsen right ventricular failure.

MATERIALS AND METHODS

We reviewed cardiac MRI exams performed at a tertiary pediatric hospital from January 2005 to January 2014. We identified patients with repaired tetralogy and unrepaired partial anomalous pulmonary venous connection. We used age- and gender-matched repaired tetralogy patients without partial anomalous pulmonary venous connection as controls. We analyzed the MRI results and surgical course and performed comparative statistics to identify group differences.

RESULTS

There were eight patients with repaired tetralogy and unrepaired partial anomalous pulmonary venous connection and 16 controls. In all cases, the partial anomalous pulmonary venous connection was not detected on preoperative echocardiography. There were no significant differences in surgical course and body surface area between the two groups. Repaired tetralogy patients with unrepaired partial anomalous pulmonary venous connection showed significantly higher indexed right ventricular end diastolic volume (149 ± 33 mL/m(2) vs. 118 ± 30 mL/m(2)), right ventricle to left ventricle size ratios (3.1 ± 1.3 vs. 1.9 ± 0.5) and a higher incidence of reduced right ventricular ejection fraction compared to controls (3/8 vs. 0/16).

CONCLUSION

Repaired tetralogy of Fallot with unrepaired partial anomalous pulmonary venous connection is associated with reduced right ventricular ejection fraction and more significant right ventricular dilation.

Effect of papillary muscles and trabeculae on left ventricular measurement using cardiovascular magnetic resonance imaging in patients with hypertrophic cardiomyopathy

Objective

To evaluate the influence of papillary muscles and trabeculae on left ventricular (LV) cardiovascular magnetic resonance (CMR) analysis using three methods of cavity delineation (classic or modified inclusion methods, and the exclusion method) in patients with hypertrophic cardiomyopathy (HCM).

Materials and Methods

This retrospective study included 20 consecutive HCM patients who underwent 1.5-T CMR imaging with short-axis cine stacks of the entire LV. LV measurements were performed using three different methods of manual cavity delineation of the endocardial and epicardial contours: method A, presumed endocardial boundary as seen on short-axis cine images; method B, including solely the cavity and closely adjacent trabeculae; or method C, excluding papillary muscles and trabeculae. Ascending aorta forward flow was measured as reference for LV-stroke volume (SV). Interobserver reproducibility was assessed using intraclass correlation coefficients.

Results

Method A showed larger end-diastole and end-systole volumes (largest percentage differences of 25% and 68%, respectively, p < 0.05), compared with method C. The ejection fraction was 55.7 ± 6.9% for method A, 68.6 ± 8.4% for B, and 71.7 ± 7.0% for C (p < 0.001). Mean mass was also significantly different: 164.6 ± 47.4 g for A, 176.5 ± 50.5 g for B, and 199.6 ± 53.2 g for C (p < 0.001). LV-SV error was largest with method B (p < 0.001). No difference in interobserver agreement was observed (p > 0.05).

Conclusion

In HCM patients, LV measurements are strikingly different dependent on whether papillary muscles and trabeculae are included or excluded. Therefore, a consistent method of LV cavity delineation may be crucial during longitudinal follow-up to avoid misinterpretation and erroneous clinical decision-making.

The right ventricle in pulmonary arterial hypertension: disorders of metabolism, angiogenesis and adrenergic signaling in right ventricular failure

The right ventricle (RV) is the major determinant of functional state and prognosis in pulmonary arterial hypertension. RV hypertrophy (RVH) triggered by pressure overload is initially compensatory but often leads to RV failure. Despite similar RV afterload and mass some patients develop adaptive RVH (concentric with retained RV function), while others develop maladaptive RVH, characterized by dilatation, fibrosis, and RV failure. The differentiation of adaptive versus maladaptive RVH is imprecise, but adaptive RVH is associated with better functional capacity and survival. At the molecular level, maladaptive RVH displays greater impairment of angiogenesis, adrenergic signaling, and metabolism than adaptive RVH, and these derangements often involve the left ventricle. Clinically, maladaptive RVH is characterized by increased N-terminal pro-brain natriuretic peptide levels, troponin release, elevated catecholamine levels, RV dilatation, and late gadolinium enhancement on MRI, increased (18)fluorodeoxyglucose uptake on positron emission tomography, and QTc prolongation on the ECG. In maladaptive RVH there is reduced inotrope responsiveness because of G-protein receptor kinase-mediated downregulation, desensitization, and uncoupling of β-adrenoreceptors. RV ischemia may result from capillary rarefaction or decreased right coronary artery perfusion pressure. Maladaptive RVH shares metabolic abnormalities with cancer including aerobic glycolysis (resulting from a forkhead box protein O1-mediated transcriptional upregulation of pyruvate dehydrogenase kinase), and glutaminolysis (reflecting ischemia-induced cMyc activation). Augmentation of glucose oxidation is beneficial in experimental RVH and can be achieved by inhibition of pyruvate dehydrogenase kinase, fatty acid oxidation, or glutaminolysis. Therapeutic targets in RV failure include chamber-specific abnormalities of metabolism, angiogenesis, adrenergic signaling, and phosphodiesterase-5 expression. The ability to restore RV function in experimental models challenges the dogma that RV failure is irreversible without regression of pulmonary vascular disease.

MR, CT, and PET imaging in pericardial disease

Although echocardiography remains the standard diagnostic tool for identifying pericardial diseases, procedures with better delineation of morphology and heart function are often required. The pericardium consists of an inner visceral (epicardium) and outer parietal layer (pericardium), which constitute for the pericardial cavity. Pericardial effusion can occur as transudate, exudate, pyopneumopericardium, or hemopericardium. Potential causes are inflammatory processes, that is, pericarditis due to autoimmune or infective reasons, neoplasms, irradiation, or systemic disorders, chronic renal failure, endocrine, or metabolic diseases. Pericardial fat can mimic pericardial effusion. Using various image-acquisition sequences, MRI allows identifying and separating fluid and solid structures. Fast spin-echo T1-weighted sequences with black-blood preparation are favourably used for morphological evaluation. Fast spin-echo T2-weighted sequences, particularly with fat saturation, and short-tau inversion-recovery sequences are useful to visualize oedema and inflammation. For further tissue characterization, delayed inversion-recovery imaging is used. Therefore, image acquisition is performed at 5-20 min subsequent to contrast agent administration, the so-called technique of late gadolinium enhancement. Ventricular volumes and myocardial mass can be assessed accurately by steady-state free-precession sequences, which is required to measure cardiac function and ventricular wall stress. Constrictive pericarditis usually results from chronic inflammatory processes leading to increased stiffness, which impedes the slippage of both pericardial layers and thereby the normal cardiac filling. CT imaging can favourably assess pericardial calcification. Thus, MR and CT imaging allow a comprehensive delineation of the pericardium. Superior to echocardiography, both methods provide a larger field of view and depiction of the complete chest including abnormalities of the surrounding mediastinum and lungs. PET provides unique information on the in vivo metabolism of 18-fluorodeoxyglucose that can be superimposed on CT findings and is useful for identifying inflammatory processes or masses, for example neoplasms. These imaging techniques provide advanced information of anatomy and cardiac function to optimize the pericardial access, for example by the AttachLifter system, for diagnosis and treatment.

Enlarged right ventricular size at 11 years' follow-up after closure of secundum-type atrial septal defect in children

BACKGROUND

The fate of right ventricular dimensions after surgical closure of secundum-type atrial septal defects remains unclear. The objectives of this study were to assess ventricular dimensions, exercise capability, and arrhythmias of patients operated for secundum-type atrial septal defect and compare the results with those in healthy references.

METHODS

A total of 78 consecutive patients underwent surgical closure for a secundum-type atrial septal defect between 1990 and 1995. In all, 42 patients were included and underwent a cross-sectional evaluation including echocardiography, magnetic resonance imaging, exercise testing, and 24-hour ambulatory electrocardiography. Patients were matched with healthy controls for gender, body surface area, and age.

RESULTS

The mean age at surgery was 4.6 plus or minus 2.8 years, and the mean age at follow-up was 16 plus or minus 3 years. There were no residual intracardiac lesions. The mean right ventricular endsystolic volume was significantly larger in patients (142 ± 26 millilitres) than in references (137 ± 28 millilitres; p = 0.04). In 25% of the patients, right ventricular end-systolic volume was larger than the 95th percentile for references. No relevant arrhythmias were detected. Exercise testing did not reveal differences with healthy references: maximal power (169 ± 43 Watt patients versus 172 ± 53 controls; p = 0.8), maximal oxygen uptake (38 ± 8 versus 41 ± 13 millilitres per minute per kilogram; p = 0.1).

COMMENT

After surgical closure of secundum-type atrial septal defect, right ventricular end-systolic volume is increased. These findings have no impact on rhythm status or exercise capacity at this stage of follow-up, but may have implications for the timing of surgery or the technique of closure if confirmed in longer follow-up.

Accuracy of right and left ventricular functional assessment by short-axis vs axial cine steady-state free-precession magnetic resonance imaging: intrapatient correlation with main pulmonary artery and ascending aorta phase-contrast flow measurements

OBJECTIVE

The left ventricle (LV) is routinely assessed with cardiac magnetic resonance imaging (MRI) by using short-axis orientation; it remains unclear whether the right ventricle (RV) can also be adequately assessed in this orientation or whether dedicated axial orientation is required. We used phase-contrast (PC) flow measurements in the main pulmonary artery (MPA) and the ascending aorta (Aorta) as nonvolumetric standard of reference and compared RV and LV volumes in short-axis and axial orientations.

METHODS

A retrospective analysis identified 30 patients with cardiac MRI data sets. Patients underwent MRI (1.5 T or 3 T), with retrospectively gated cine steady-state free-precession in axial and short-axis orientations. PC flow analyses of MPA and Aorta were used as the reference measure of RV and LV output.

RESULTS

There was a high linear correlation between MPA-PC flow and RV-stroke volume (SV) short axis (r = 0.9) and RV-SV axial (r = 0.9). Bland-Altman analysis revealed a mean offset of 1.4 mL for RV axial and -2.3 mL for RV-short-axis vs MPA-PC flow. There was a high linear correlation between Aorta-PC flow and LV-SV short-axis (r = 0.9) and LV-SV axial (r = 0.9). Bland-Altman analysis revealed a mean offset of 4.8 m for LV short axis and 7.0 mL for LV axial vs Aorta-PC flow. There was no significant difference (P = .6) between short-axis-LV SV and short-axis-RV SV.

CONCLUSION

No significant impact of the slice acquisition orientation for determination of RV and LV stroke volumes was found. Therefore, cardiac magnetic resonance workflow does not need to be extended by an axial data set for patients without complex cardiac disease for assessment of biventricular function and volumes.

Sex and race differences in right ventricular structure and function: the multi-ethnic study of atherosclerosis-right ventricle study

BACKGROUND

Right ventricular (RV) morphology is an important predictor of outcomes in heart and lung disease; however, determinants of RV anatomy have not been well studied. We examined the demographic factors associated with RV morphology and function in a population-based multiethnic sample free of clinical cardiovascular disease.

METHODS AND RESULTS

In the Multi-Ethnic Study of Atherosclerosis (MESA), cardiac magnetic resonance imaging was performed on 5098 participants. Right ventricular volumes and mass were available for 4204 participants. Normative equations for RV parameters were derived with an allometric approach. The study sample (n=4123) was 61.5±10.1 years of age and 47.5% men. Older age was associated with lower RV mass (≈5% lower mass per decade), with larger age-related decrements in men than in women (P<0.05 for interaction). Older age was also associated with higher RV ejection fraction, an association that differed between races/ethnicities (P≤0.01 for interaction). Overall, men had greater RV mass (≈8%) and larger RV volumes than women, but had lower RV ejection fraction (4% in absolute terms; P<0.001). Blacks had lower RV mass than whites (P≤0.002), whereas Hispanics had higher RV mass (P≤0.02). When the derived normative equations were used, 7.3% (95% confidence interval, 6.5 to 8.1) met the criteria for RV hypertrophy, and 5.9% (95% confidence interval, 5.2 to 6.6) had RV dysfunction.

CONCLUSION

Age, sex, and race are associated with significant differences in RV mass, RV volumes, and RV ejection fraction, potentially explaining distinct responses of the RV to cardiopulmonary disease.

Assessment of pulmonary hypertension what CT and MRI can provide

RATIONALES AND OBJECTIVES

Pulmonary hypertension (PH) is a life-threatening condition, characterized by elevated pulmonary arterial pressure, which is confirmed based on invasive right heart catheterization (RHC). Noninvasive examinations may support diagnosis of PH before proceeding to RHC and play an important role in management and treatment of the disease. Although echocardiography is considered a standard tool in diagnosis, recent advances have made computed tomography (CT) and magnetic resonance (MR) imaging promising tools, which may provide morphologic and functional information. In this article, we review image-based assessment of PH with a focus on CT and MR imaging.

CONCLUSIONS

CT may provide useful morphologic information for depicting PH and seeking for underlying diseases. With the accumulated technological advancement, CT and MRI may provide practical tools for not only morphologic but also functional assessment of patients with PH.

Computed tomography and magnetic resonance imaging of pulmonary hypertension: Pulmonary vessels and right ventricle

Pulmonary hypertension (PH) is very heterogeneous and the classification identifies five major groups including many associated disease processes. The treatment of PH depends on the underlying cause and accurate classification is paramount. A comprehensive assessment to identify the cause and severity of PH is therefore needed. Furthermore, follow-up assessments are required to monitor changes in disease status and response to therapy. Traditionally, the diagnostic imaging work-up of PH comprised mainly echocardiography, invasive right heart catheterization, and ventilation/perfusion scintigraphy. Due to technical advances, multidetector row computed tomography (CT) and magnetic resonance imaging (MRI) have become important and complementary investigations in the evaluation of patients with suspected PH. Both modalities are reviewed and recommendations for clinical use are given.

Quantification of left ventricular remodeling in response to isolated aortic or mitral regurgitation

BACKGROUND

The treatment of patients with aortic regurgitation (AR) or mitral regurgitation (MR) relies on the accurate assessment of the severity of the regurgitation as well as its effect on left ventricular (LV) size and function. Cardiovascular Magnetic Resonance (CMR) is an excellent tool for quantifying regurgitant volumes as well as LV size and function. The 2008 AHA/ACC management guidelines for the therapy of patients with AR or MR only describe LV size in terms of linear dimensions (i.e. end-diastolic and end-systolic dimension). LV volumes that correspond to these linear dimensions have not been published in the peer-reviewed literature. The purpose of this study is to determine the effect of regurgitant volume on LV volumes and chamber dimensions in patients with isolated AR or MR and preserved LV function.

METHODS

Regurgitant volume, LV volume, mass, linear dimensions, and ejection fraction, were determined in 34 consecutive patients with isolated AR and 23 consecutive patients with MR and no other known cardiac disease.

RESULTS

There is a strong, linear relationship between regurgitant volume and LV end-diastolic volume index (aortic regurgitation r2 = 0.8, mitral regurgitation r2 = 0.8). Bland-Altman analysis of regurgitant volume shows little interobserver variation (AR: 0.6 +/- 4 ml; MR 4 +/- 6 ml). The correlation is much poorer between regurgitant volume and commonly used clinical linear measures such as end-systolic dimension (mitral regurgitation r2 = 0.3, aortic regurgitation r2 = 0.5). For a given regurgitant volume, AR causes greater LV enlargement and hypertrophy than MR.

CONCLUSION

CMR is an accurate and robust technique for quantifying regurgitant volume in patients with AR or MR. Ventricular volumes show a stronger correlation with regurgitant volume than linear dimensions, suggesting LV volumes better reflect ventricular remodeling in patients with isolated mitral or aortic regurgitation. Ventricular volumes that correspond to published recommended linear dimensions are determined to guide the timing of surgical intervention.

Impact of papillary and trabecular muscles on quantitative analyses of cardiac function in hypertrophic cardiomyopathy

PURPOSE

To examine the impact of cardiovascular magnetic resonance (CMR) partitioning methods on volumetric analysis in hypertrophic cardiomyopathy (HCM) patients. The standard CMR method for partitioning ventricular myocardium from ventricular cavity includes the myocardial papillary and trabecular muscles in the cavity volume. This approach may misrepresent ventricular mass and volume in patients with HCM due to large papillary muscles and extensive trabeculations.

MATERIALS AND METHODS

Ventricular volume and mass analyses were performed in 30 patients with HCM using the standard method and a detailed method that excluded papillary and trabecular muscles from the left ventricular (LV) volume while including them in LV mass. We also analyzed the degree of mitral regurgitation and compared the results with Doppler echocardiography in a subgroup of 12 patients. Interobserver variability was assessed.

RESULTS

The detailed method yielded 17% higher indexed LV mass, 20% lower indexed LV diastolic volume, 13% higher LV ejection fraction (EF) (all P < 0.0001). The resultant mitral regurgitant volumes using the detailed method had less discrepancy with Doppler echocardiography results compared with the results from the standard methods. Interobserver variability was similar by both methods.

CONCLUSION

For patients with HCM, a detailed analysis in which the ventricular papillary and trabecular muscles are excluded from LV volume is preferred.

Impact of right ventricular dilation on left ventricular myocardial deformation in patients after surgical repair of tetralogy of fallot

Left ventricular (LV) dysfunction is 1 of the major determinants of late adverse clinical outcomes in patients after surgical repair of tetralogy of Fallot (TOF). The aim of this study was to test the hypothesis that LV myocardial deformation is impaired in patients after TOF repair and related to right ventricular (RV) dilation and exercise capacity. Longitudinal, radial, and circumferential LV myocardial deformation was determined using speckle-tracking echocardiography in 23 postoperative patients with TOF and compared to that of 23 age-matched controls. Relations between LV strain and strain rate (SR) and RV volumes and exercise parameters were determined in patients. Compared to controls, patients had reduced global LV longitudinal, radial, and circumferential strain (all p values <0.05). Patients with significantly increased RV end-systolic volume (>2 SDs higher than normal; n = 17) had reduced global LV circumferential strain (p = 0.048) and SR (p = 0.038), but similar longitudinal and radial speckle-tracking echocardiographic parameters, compared to those without (n = 6). RV end-systolic volume was correlated inversely with global LV circumferential strain and SR (r = -0.58, p = 0.004, and r = -0.58, p = 0.005, respectively), while RV end-diastolic volume was correlated only with global LV circumferential strain (r = -0.43, p = 0.047). In patients, the LV ejection fraction was correlated with global LV circumferential strain (r = 0.54, p = 0.01) and SR (r = 0.66, p = 0.001) but not with longitudinal or radial speckle-tracking echocardiographic parameters. Using multivariate analysis, global LV circumferential SR (beta = 0.66, p = 0.001) and male gender (beta = 0.46, p = 0.012) were identified as independent predictors of peak oxygen consumption. In conclusion, the negative impact of RV dilation on LV function relates to its influence on LV circumferential strain and SR in patients after TOF repair.

Comparison of MRI, 64-slice MDCT and DSCT in assessing functional cardiac parameters of a moving heart phantom

To compare magnetic resonance imaging (MRI), 64-slice multi-detector computed tomography (MDCT) and dual-source computed tomography (DSCT) in assessing global function parameters using a moving heart phantom. A moving heart phantom with known volumes (215–258 ml) moving at 50–100 beats per minute was examined by three different imaging modalities using clinically implemented scanning protocols. End-diastolic and end-systolic volumes were calculated by two experienced observers using dedicated post-processing tools. Ejection fraction (EF) and cardiac output (CO) were calculated and mutually compared using Bland-Altman plots. MRI underestimated the ejection EF by 16.1% with a Bland-Altman interval (B-A) of [-4.35 (-2.48) -0.60]. Sixty-four-slice MDCT overestimated the EF by 2.6% with a relatively wide B-A interval of [-3.40 (0.40) 4.20]. DSCT deviated the least from the known phantom volumes, underestimating the volumes by 0.8% with a B-A interval of [-1.17 (-0.13) 0.91]. CO analysis showed similar results. Furthermore, a good correlation was found between DSCT and MRI for EF and CO results. MRI systematically underestimates functional cardiac parameters, ejection fraction and cardiac output of a moving heart phantom. Sixty-four-slice MDCT underestimates or overestimates these functional parameters depending on the heart rate because of limited spatial resolution. DSCT deviates the least from these functional parameters compared to MRI, EBT and 64-slice MDCT.

Segmentation of cardiac cine MR images of left and right ventricles: interactive semiautomated methods and manual contouring by two readers with different education and experience

PURPOSE

To test interactive semiautomated methods (ISAM) vs. manual contouring (MC) in segmenting cardiac cine MR images.

MATERIALS AND METHODS

Short-axis images of 10 consecutive patients (1.5-81.5 years of age) were evaluated by a trained radiologist (R1) and a low-trained engineer (R2). Each of them performed four independent reading sessions: two using ISAM and two using MC. Left ventricle (LV) myocardial mass (LVMM), LV ejection fraction (LVEF), and right ventricle (RV) ejection fraction (RVEF) were obtained. Bland-Altman analysis and Wilcoxon test were used.

RESULTS

The bias +/- 2 standard deviations (SD) of ISAM vs. MC for LVMM (g) was -5.7 +/- 13.4 (R1) and -5.5 +/- 26.3 (R2); for LVEF (%) it was -1.4 +/- 13.0 and -2.9 +/- and 6.8; for RVEF (%) it was 2.6 +/- 17.0 and 1.0 +/- 16.7. Considering both readers/methods, intraobserver bias +/- 2 SD ranged from 0.3 +/- 25.3 to -6.8 +/- 23.0, from 0.2 +/- 8.0 to -4.4 +/- 15.8, and from -0.0 +/- 26.4 to -4.6 +/- 27.8, respectively. Interobserver bias +/- 2 SD was -25.9 +/- 46.0 (ISAM) and 26.1 +/- 36.4 (MC), -1.4 +/- 8.6 (ISAM) and 0.1 +/- 17.9 (MC), and 0.7 +/- 23.3 and 2.3 +/- 29.8, respectively. Larger SDs were systematically found for RVEF vs. LVEF. Segmentation times: five minutes for LV with ISAM (both readers); for LV with MC, six (R1) vs. nine minutes (R2) (P < 0.001); five to six minutes for RV (both methods /readers). R2 significantly reduced LV segmentation times from nine (MC) to five minutes (ISAM) (P < 0.001).

CONCLUSION

A highly reproducible LV segmentation was performed in a short time by R1. The advantage of ISAM vs. MC for LV segmentation was a time saving only for R2. For RVEF, a lower reproducibility was observed for both methods and readers.

Evaluating the systemic right ventricle by CMR: the importance of consistent and reproducible delineation of the cavity

BACKGROUND

The method used to delineate the boundary of the right ventricle (RV), relative to the trabeculations and papillary muscles in cardiovascular magnetic resonance (CMR) ventricular volume analysis, may matter more when these structures are hypertrophied than in individuals with normal cardiovascular anatomy. This study aimed to compare two methods of cavity delineation in patients with systemic RV.

METHODS

Twenty-nine patients (mean age 34.7 +/- 12.4 years) with a systemic RV (12 with congenitally corrected transposition of the great arteries (ccTGA) and 17 with atrially switched (TGA) underwent CMR. We compared measurements of systemic RV volumes and function using two analysis protocols. The RV trabeculations and papillary muscles were either included in the calculated blood volume, the boundary drawn immediately within the apparently compacted myocardial layer, or they were manually outlined and excluded. RV stroke volume (SV) calculated using each method was compared with corresponding left ventricular (LV) SV. Additionally, we compared the differences in analysis time, and in intra- and inter-observer variability between the two methods. Paired samples t-test was used to test for differences in volumes, function and analysis time between the two methods. Differences in intra- and inter-observer reproducibility were tested using an extension of the Bland-Altman method.

RESULTS

The inclusion of trabeculations and papillary muscles in the ventricular volume resulted in higher values for systemic RV end diastolic volume (mean difference 28.7 +/- 10.6 ml, p < 0.001) and for end systolic volume (mean difference 31.0 +/- 11.5 ml, p < 0.001). Values for ejection fraction were significantly lower (mean difference -7.4 +/- 3.9%, p < 0.001) if structures were included. LV SV did not differ significantly from RV SV for both analysis methods (p = NS). Including structures resulted in shorter analysis time (p < 0.001), and showed better inter-observer reproducibility for ejection fraction (p < 0.01).

CONCLUSION

The choice of method for systemic RV cavity delineation significantly affected volume measurements, given the CMR acquisition and analysis systems used. We recommend delineation outside the trabeculations for routine clinical measurements of systemic RV volumes as this approach took less time and gave more reproducible measurements.

Evaluation of right ventricular function with multidetector computed tomography: comparison with magnetic resonance imaging and analysis of inter- and intraobserver variability

This study was performed to prospectively compare multidetector computed tomography (MDCT) with 16 simultaneous sections and magnetic resonance imaging (MRI) for the assessment of global right ventricular function in 50 patients. MDCT using a semiautomatic analysis tool showed good correlation with MRI for end-diastolic volume (EDV, r=0.83, p<0.001), end-systolic volume (ESV, r=0.86, p<0.001) and stroke volume (SV, r=0.74, p<0.001), but only a moderate correlation for the ejection fraction (EF, r=0.67, p<0.001). Bland Altman analysis revealed a slight, but insignificant overestimation of EDV (4.0 ml, p=0.08) and ESV (2.4 ml, p=0.07), and underestimation of EF (0.1%, p=0.92) with MDCT compared with MRI. All limits of agreement between both modalities (EF: +/-15.7%, EDV: +/-31.0 ml, ESV: +/-18.0 ml) were in a moderate but acceptable range. Interobserver variability of MDCT was not significantly different from that of MRI. For MDCT software, the post-processing time was significantly longer (19.6+/-5.8 min) than for MRI (11.8+/-2.6 min, p<0.001). Accurate assessment of right ventricular volumes by 16-detector CT is feasible but still rather time-consuming.

Comparison of left and right ventricular volume measurement using the Simpson's method and the area length method

PURPOSE

To compare ventricular volume measurement using a volumetric approach in the three standard cardiac planes and ventricular volume estimation by a geometrical model, the Area-Length method (ALM).

MATERIALS AND METHODS

Fifty-six healthy volunteers were examined (27 males, 29 females) on a 1.5T MR-unit with ECG-triggered steady state free precision (SSFP) Cine-MR sequences and parallel image acquisition. Multiple slices in standardized planes including the short-axis view (sa), 4-chamber view (4ch), left and right 2-chamber views (2ch) were used to cover the whole heart. End-systolic and end-diastolic ventricular volumes (EDV, ESV), stroke volume (SV), and ejection fraction (EF) were calculated with Simpson's rule in all planes and with ALM in the 2ch and 4ch planes. Global function parameters measured in the sa plane were compared with those obtained in the other imaging planes.

RESULTS

A very good correlation is observed when comparing functional parameters calculated with Simpson's rule in all imaging planes: for instance, the mean EDV/ESV of the left and right ventricle of the female population group measured in sa, 4ch, and 2ch: left ventricle EDV/ESV 114.3/44.4, 120.9/46.5, and 117.7/45.3 ml; right ventricle EDV/ESV 106.6/46.0, 101.2/41.1, and 103.5/43.0 ml. Functional parameters of the left ventricle calculated with ALM in 2ch and 4ch correlate to parameters obtained in sa with Simpson's rule in the range of 5-10%: for instance, the EDV/ESV of the left ventricle of the male population group measured in the sa, 4ch, and 2ch: 160.3/63.5, 163.1/59.0, and 167.0/65.7 ml. Functional parameters of the right ventricle measured with ALM in 4ch are 40-50% lower and calculated in 2ch almost double as high as compared with the parameters obtained in sa with Simpson's rule: for instance, male right ventricular EDV/ESV measured in sa, 4ch, and 2ch: 153.4/68.1, 97.5/34.5, and 280.2/123.2 ml. The EF correlates for all imaging planes measured with the Simpson's rule in both ventricles and using ALM in the left ventricle except for males with an overestimation of less than 6%. The EF of the right ventricle is calculated higher using ALM in 4ch and 2ch compared to the EF calculated in sa: female/male EF of the right ventricle measured in the sa, 4ch, and 2ch: 56.8/55.7, 66.0/65.0, and 60.0/57.0%.

CONCLUSION

In the setting of healthy volunteers the ALM method should not be used in 2ch and 4ch planes of the right ventricle because of lacking correlation of global functional parameters compared to those obtained in the sa plane. Using Simpson's rule functional parameters correlate well to each other in the different imaging planes.

Pattern and distribution of myocardial fibrosis in systemic sclerosis: a delayed enhanced magnetic resonance imaging study

OBJECTIVE

To assess the prevalence and pattern of myocardial fibrosis as detected by delayed enhanced magnetic resonance imaging (DE-MRI) in patients with systemic sclerosis (SSc), and to evaluate a possible association between myocardial fibrosis and cardiac arrhythmias.

METHODS

Forty-one patients with SSc underwent 24-hour Holter monitoring, Doppler echocardiography, and DE-MRI following gadolinium administration.

RESULTS

Technically acceptable DE-MRIs were obtained in 36 patients with SSc. Enhancement on DE-MRI, consistent with myocardial fibrosis, was observed in 24 of these patients (66%), and it was invariably midwall with a linear pattern, mostly involving basal and midcavity segments of the left ventricle. The volume of enhancement (total volume percentage index [TVPI]) did not differ between patients with diffuse SSc and those with limited SSc (mean +/- SD 1.46 +/- 1.73% versus 1.44 +/- 1.77%; P = 0.98). Patients with a long duration (> or = 15 years) of Raynaud's phenomenon had a greater number of enhancing segments (mean +/- SD 6.55 +/- 4.93 versus 2.96 +/- 3.46; P = 0.017) and a greater TVPI (mean +/- SD 2.44 +/- 1.97% versus 1.02 +/- 1.43%; P = 0.02) than those with a duration of Raynaud's phenomenon <15 years. Nineteen patients with SSc (53%) had abnormal Holter study results. Compared with patients with normal Holter study results, those with abnormal results had a greater number of enhancing segments (mean +/- SD 5.4 +/- 4.8 versus 2.5 +/- 2.9; P < 0.05) and a greater TVPI (mean +/- SD 2.1 +/- 1.9% versus 0.8 +/- 1.2%; P < 0.05).

CONCLUSION

DE-MRI can identify myocardial fibrosis in a significant percentage of patients with SSc and may be a useful noninvasive tool for determining cardiac involvement.