Pressure overloaded right ventricles: a multicenter study on the importance of trabeculae in RV function measured by CMR

Cardiac magnetic resonance (CMR) imaging is the preferred method to measure right ventricular (RV) volumes and ejection fraction (RVEF). This study aimed to determine the impact of excluding trabeculae and papillary muscles on RV volumes and function in patients with RV pressure and/or volume overload and healthy controls and its reproducibility using semi-automatic software. Eighty patients (pulmonary hypertension, transposition of the great arteries after arterial switch operation and after atrial switch procedure and repaired Tetralogy of Fallot) and 20 controls underwent short-axis multislice cine CMR. End diastolic volume (EDV), end systolic volume (ESV), RV mass and RVEF were measured using 2 methods. First, manual contour tracing of RV endo- and epi-cardial borders was performed. Thereafter, trabeculae were excluded from the RV blood volume using semi-automatic pixel-intensity based software. Both methods were compared using a Student T test and 25 datasets were re-analyzed for reproducibility. Exclusion of trabeculae resulted in significantly decreased EDV; ranging from ?5.7 ± 1.7 ml/m² in controls to ?29.2 ± 6.6 ml/m² in patients after atrial switch procedure. RVEF significantly increased in all groups, ranging from an absolute increase of 3.4 ± 0.8 % in healthy controls to 10.1 ± 2.3 % in patients after atrial switch procedure. Interobserver agreement of method 2 was equal to method 1 for RVEDV, RVESV and RVEF and superior for RV mass. In patients with overloaded RVs exclusion of trabeculae from the blood volume results in a significant change in RV volumes, RVEF and RV mass. Exclusion of trabeculae is highly reproducible when semi-automatic pixel-intensity based software is used.     

Assessment of right ventricular function with 320-slice volume cardiac CT: comparison with cardiac magnetic resonance imaging

To evaluate the accuracy and feasibility of right ventricular function parameters measurement using 320-slice volume cardiac CT. Retrospective analysis of 50 consecutive patients (23 men, 27 women) with suspected pulmonary diseases was performed in electrocardiogram (ECG)-gated cardiac CT and cardiac magnetic resonance (CMR). Parameters including right ventricular end-diastolic volume (RVEDV), right ventricular end- systolic volume (RVESV), right ventricular stroke volume (RVSV), right ventricular cardiac output (RVCO), and right ventricular ejection fraction (RVEF) were semi-automatically and separately calculated from both CT and CMR data. Significant difference between measurements was measured by paired t test and two-variable linear regression analysis with Pearson’s correlation coefficient. Bland–Altman analysis was performed in each pair of parameters. There was little variability between the measurements by the two observers (kappa = 0.895–0.980, P < 0.05). There was good correlation between all parameters obtained by CT and CMR (P < 0.001): RVEDV (108.5 ± 21.9 ml, 113.5 ± 24.8 ml, r = 0.944), RVESV (69.8 ± 33.4 ml, 73.2 ± 35.4 ml, r = 0.972), RVSV (39.0 ± 13.2 ml, 40.2 ± 13.3 ml, r = 0.977), RVCO (2.6 ± 0.7 l, 2.6 ± 0.7 l. r = 0.958), RVEF (38.8 ± 19.1 %, 39.1 ± 19.3 %, r = 0.990), and there was no significant difference between CT and CMR measurements in RVEF (n = 50, t = ?0.677, P > 0.05). 320-slice volume cardiac CT is an accurate non-invasive technique to evaluate RV function.     

Fully automated right ventricular volumetry from ECG-gated coronary CT angiography data: evaluation of prototype software

Enlargement and dysfunction of the right ventricle (RV) is a sign and outcome predictor of many cardiopulmonary diseases. Due to the complex geometry of the RV exact volumetry is cumbersome and time-consuming. We evaluated the performance of prototype software for fully automated RV segmentation and volumetry from cardiac CT data. In 50 retrospectively ECG-gated coronary CT angiography scans the endsystolic (RVVmin) and enddiastolic (RVVmax) volume of the right ventricle was calculated fully automatically by prototype software. Manual slice segmentation by two independent radiologists served as the reference standard. Measurement periods were compared for both methods. RV volumes calculated with the software were in strong agreement with the results from manual slice segmentation (Bland–Altman r = 0.95–0.98; p < 0.001; Lin’s correlation Rho = 0.87–0.96, p < 0.001) for RVVmax and RVVmin with excellent interobserver agreement between both radiologists (r = 0.97; p < 0.001). The measurement period was significantly shorter with the software (153 ± 9 s) than with manual slice segmentation (658 ± 211 s). The prototype software demonstrated very good performance in comparison to the reference standard. It promises robust RV volume results and minimizes postprocessing time.     

Evaluation of knowledge-based reconstruction for magnetic resonance volumetry of the right ventricle after arterial switch operation for dextro-transposition of the great arteries

Right ventricular (RV) volume and function evaluation is essential in the follow-up of patients after arterial switch operation (ASO) for dextro-transposition of the great arteries (d-TGA). Cardiac magnetic resonance (CMR) imaging using the Simpson’s method is the gold-standard for measuring these parameters. However, this method can be challenging and time-consuming, especially in congenital heart disease. Knowledge-based reconstruction (KBR) is an alternative method to derive volumes from CMR datasets. It is based on the identification of a finite number of anatomical RV landmarks in various planes, followed by computer-based reconstruction of the endocardial contours by matching these landmarks with a reference library of representative RV shapes. The purpose of this study was to evaluate the feasibility, accuracy, reproducibility and labor intensity of KBR for RV volumetry in patients after ASO for d-TGA. The CMR datasets of 17 children and adolescents (males 11, median age 15) were studied for RV volumetry using both KBR and Simpson’s method. The intraobserver, interobserver and intermethod variabilities were assessed using Bland–Altman analyses. Good correlation between KBR and Simpson’s method was noted. Intraobserver and interobserver variability for KBR showed excellent agreement. Volume and function assessment using KBR was faster when compared with the Simpson’s method (5.1?±?0.6 vs. 6.7?±?0.9 min, p?<?0.001). KBR is a feasible, accurate, reproducible and fast method for measuring RV volumes and function derived from CMR in patients after ASO for d-TGA.     

Non-invasive Evaluation of Right Ventricular Function with Real-Time 3-D Echocardiography

The aim of this study was to evaluate the accuracy and feasibility of real-time 3-D echocardiography (3-DE) in assessing right ventricular (RV) systolic function. A latex balloon was inserted into the right ventricle of 20 freshly harvested pig hearts which were then passively driven by a pulsatile pump apparatus. The RV global longitudinal strain (GLS), global circumferential strain (GCS), global area strain (GAS) and RV ejection fraction (RVEF), derived from 3-DE, as well as the RVEF obtained from 2-D echocardiography (2-DE) were quantified at different stroke volumes (30–70 mL) and compared with sonomicrometry data. In all comparisons, 3-D GLS, GCS, GAS, 2-D RVEF and 3-D RVEF exhibited strong correlations with sonomicrometry data (r = 0.89, 0.79, 0.74, 0.80, and 0.93, respectively; all p values < 0.001). Bland–Altman analyses revealed slight overestimations of echo-derived GLS, GCS, 2-DE RVEF and 3-DE RVEF compared with sonomicrometry values (bias = 1.55, 2.72, 3.59 and 2.21, respectively). Furthermore, there is better agreement among GLS, 3-D RVEF and the sonomicrometry values than between GCS and 2-D RVEF. Real-time 3-DE is more feasible and accurate for assessing RV function than 2-DE. GLS is a potential alternative parameter for quantifying RV systolic function.     

The importance of trabecular hypertrophy in right ventricular adaptation to chronic pressure overload

To assess the contribution of right ventricular (RV) trabeculae and papillary muscles (TPM) to RV mass and volumes in controls and patients with pulmonary arterial hypertension (PAH). Furthermore, to evaluate whether TPM shows a similar response as the RV free wall (RVFW) to changes in pulmonary artery pressure (PAP) during follow-up. 50 patients underwent cardiac magnetic resonance (CMR) and right heart catheterization at baseline and after one-year follow-up. Furthermore 20 controls underwent CMR. RV masses were assessed with and without TPM. TPM constituted a larger proportion of total RV mass and RV end-diastolic volume (RVEDV) in PAH than in controls (Mass: 35 ± 7 vs. 25 ± 5 %; p < 0.001; RVEDV: 17 ± 6 vs. 12 ± 6 %; p = 0.003). TPM mass was related to the RVFW mass in patients (baseline: R = 0.65; p < 0.001; follow-up: R = 0.80; p < 0.001) and controls (R = 0.76; p < 0.001). In PAH and controls, exclusion of TPM from the assessment resulted in altered RV mass, volumes and function than when included (all p < 0.01). Changes in RV TPM mass (β = 0.44; p = 0.004) but not the changes in RVFW mass (p = 0.095) were independently related to changes in PAP during follow-up. RV TPM showed a larger contribution to total RV mass in PAH (~35 %) compared to controls (~25 %). Inclusion of TPM in the analyses significantly influenced the magnitude of the RV volumes and mass. Furthermore, TPM mass was stronger related to changes in PAP than RVFW mass. Our results implicate that TPM are important contributors to RV adaptation during pressure overload and cannot be neglected from the RV assessment.     

Correlation between right ventricular T<Subscript>1</Subscript> mapping and right ventricular dysfunction in non-ischemic cardiomyopathy

Right ventricular (RV) fibrosis is increasingly recognized as the underlying pathological substrate in a variety of clinical conditions. We sought to employ cardiac magnetic resonance (CMR) techniques of strain imaging and longitudinal relaxation time (T₁) mapping to better examine the relationship between RV function and structure. Our aim was to initially evaluate the feasibility of these techniques to evaluate the right ventricle. We then sought to explore the relationship between RV function and underlying fibrosis, along with examining the evolution of RV remodeling according to the amount of baseline fibrosis. Echocardiography was performed in 102 subjects with non-ischemic cardiomyopathy. Right ventricular parameters were assessed including: fractional area change (FAC) and longitudinal strain. The same cohort underwent CMR. Post-contrast T₁ mapping was performed as a marker of fibrosis with a Look-Locker technique using inversion recovery imaging. Mid-ventricular post-contrast T₁ values of the RV free wall, RV septum and lateral LV were calculated using prototype analysis software. Biventricular volumetric data including ejection fraction was measured by CMR using a cine short axis stack. CMR strain analysis was also performed to assess 2D RV longitudinal and radial strain. Simultaneous biochemical and anthropometric data were recorded. Subjects were followed over a median time of 29 months (IQR 20–37 months) with echocardiography to evaluate temporal change in RV FAC according to baseline post-contrast T₁ values. Longitudinal data analysis was performed to adjust for patient loss during follow-up. Subjects (62% men, 51?±?15 years) had mild to moderately impaired global RV systolic function (RVEF?=?39?±?15%; RVEDV?=?187?±?69 ml; RVESV?=?119?±?68 ml) and moderate left ventricular dysfunction at baseline (LVEF 30?±?17%). Good correlation was observed between mean LV and RV post-contrast T₁ values (r?=?0.652, p?<?0.001), with similar post-contrast T₁ values maintained in both the RV free wall and septum (r?=?0.761, p?<?0.001). CMR RVEF demonstrated a proportional correlation with echocardiographic measures of RV longitudinal function and CMR RV strain (longitudinal r?=??0.449, p?=?0.001; radial r?=??0.549, p?<?0.001). RVEF was related to RV post-contrast T₁ values, particularly in those with RV dysfunction (free wall T₁ r?=?0.259 p?=?0.027; septal T₁ r?=?0.421 p?<?0.001). RV strain was also related to RV post-contrast T₁ values (r?=??0.417, p?=?0.002). Linear regression analysis demonstrated strain and post-contrast T1 values to be independently associated with RVEF. Subjects with severe RV dysfunction (CMR RVEF <25%) demonstrated lower RV CMR strain (longitudinal p?=?0.018; radial p?<?0.001), RV T₁ values (free wall p?=?0.013; septum <0.001) and RV longitudinal echocardiography parameters despite no difference in afterload. During follow-up, those with RV free wall post-contrast T₁ values?≥?350 ms demonstrated ongoing improvement in FAC (Δ6%), whilst values <350 ms were associated with deterioration in RV function (ΔFAC?=??5%) (p?=?0.026). CMR provides a comprehensive method by which to evaluate right ventricular function. Post-contrast T₁ mapping and CMR strain imaging are technically feasible and provide incremental information regarding global RV function and structure. The proportional relationship between RV function and post-contrast T₁ values supports that myocardial fibrosis is a causative factor of RV dysfunction in NICM, irrespective of RV afterload. This same structural milieu also appears integral to the propensity for both positive and negative RV remodeling long-term, suggestive that this is also determined by the degree of underlying RV fibrosis.     

Cardiac volumetry in patients with heart failure and reduced ejection fraction: a comparative study correlating multi-slice computed tomography and magnetic resonance tomography. Reasons for intermodal disagreement

Background

In humans with normal hearts multi-slice computed tomography (MSCT) based volumetry was shown to correlate well with the gold standard, cardiac magnetic resonance imaging (CMR). We correlated both techniques in patients with various degrees of heart failure and reduced ejection fraction (HFREF) resulting from cardiac dilatation.

Methods

Twenty-four patients with a left ventricular end-diastolic volume (LV-EDV) of ≥ 150 ml measured by angiography underwent MSCT and CMR scanning for left and right ventricular (LV, RV) volumetry. MSCT based short cardiac axis views were obtained beginning at the cardiac base advancing to the apex. These were reconstructed in 20 different time windows of the RR-interval (0–95%) serving for identification of enddiastole (ED) and end-systole (ES) and for planimetry. ED and ES volumes and the ejection fraction (EF) were calculated for LV and RV. MSCT based volumetry was compared with CMR.

Results

MSCT based LV volumetry significantly correlates with CMR as follows: LV-EDV r = 0.94, LV-ESV r = 0.98 and LV-EF r = 0.93, but significantly overestimates LV-EDV and LV-ESV and underestimates EF (P < 0.0001). MSCT based RV volumetry significantly correlates with CMR as follows: RV-EDV r = 0.79, RV-ESV r = 0.78 and RV-EF r = 0.73, but again significantly overestimates RV-EDV and RV-ESV and underestimates RV-EF (P < 0.0001).

Conclusion

When compared with CMR a continuous overestimation of volumes and underestimation of EF needs to be considered when applying MSCT in HFREF patients.     

Intra-observer and interobserver variability of biventricular function, volumes and mass in patients with congenital heart disease measured by CMR imaging

Cardiovascular magnetic resonance (CMR) imaging provides highly accurate measurements of biventricular volumes and mass and is frequently used in the follow-up of patients with acquired and congenital heart disease (CHD). Data on reproducibility are limited in patients with CHD, while measurements should be reproducible, since CMR imaging has a main contribution to decision making and timing of (re)interventions. The aim of this study was to assess intra-observer and interobserver variability of biventricular function, volumes and mass in a heterogeneous group of patients with CHD using CMR imaging. Thirty-five patients with CHD (7–62 years) were included in this study. A short axis set was acquired using a steady-state free precession pulse sequence. Intra-observer and interobserver variability was assessed for left ventricular (LV) and right ventricular (RV) volumes, function and mass by calculating the coefficient of variability. Intra-observer variability was between 2.9 and 6.8% and interobserver variability was between 3.9 and 10.2%. Overall, variations were smallest for biventricular end-diastolic volume and highest for biventricular end-systolic volume. Intra-observer and interobserver variability of biventricular parameters assessed by CMR imaging is good for a heterogeneous group of patients with CHD. CMR imaging is an accurate and reproducible method and should allow adequate assessment of changes in ventricular size and global ventricular function.     

三维超声心动图对房间隔缺损患者右心功能的评估

目的应用三维超声心动图对房间隔缺损患者右心功能的进行评估。方法ASD患者5 8例,正常对照组3 2例,应用三维超声心动图,测量右心室舒张末期容量(RVEDV)、收缩末期容量(RVESV)、并计算右室射血分数(RVEF)。结果ASD患者、正常对照组RVEDV分别为( 10 1 74±2 5 17)、( 5 9 65±15 0 0 )ml;RVESV分别为( 5 6 81±16 77)、( 2 7 83±9 17)ml;RVEF分别为( 4 4 82±4 5 1) %、( 5 4 11±5 89) % ,2组间均有显著差异(P <0 0 0 1)。结论ASD患者右心室容量负荷较正常人显著增加,右心功能明显下降。     

Simple prediction of right ventricular ejection fraction using tricuspid annular plane systolic excursion in pulmonary hypertension

The present study examined whether tricuspid annular plane systolic excursion (TAPSE) can simply predict right ventricular ejection fraction (RVEF) in patients with pulmonary hypertension (PH). The TAPSE cut-off value to predict reduced RVEF was also evaluated. The association between TAPSE and cardiac magnetic resonance imaging (CMRI)-derived RVEF was examined in 53 PH patients. The accuracy of the prediction equation to calculate RVEF using TAPSE was also evaluated. In PH patients, TAPSE was strongly correlated with CMRI-derived RVEF in PH patients (r = 0.86, p < 0.0001). We then examined the accuracy of the two equations: the original regression equation (RVEF = 2.01 × TAPSE + 0.6) and the simplified prediction equation (RVEF = 2 × TAPSE). Bland–Altman plot showed that the mean difference ± limits of agreement was 0.0 ± 10.6 for the original equation and ?0.6 ± 10.6 for the simplified equation. Intraclass correlation coefficient was 0.84 for the original and 0.82 for the simplified equation. Normal RVEF was considered to be ≥40 % based on the data from 53 matched controls, and the best TAPSE cut-off value to determine reduced RVEF (<40 %) was calculated to be 19.7 mm (sensitivity 88.9 %, specificity 84.6 %). A simple equation of RVEF = 2 × TAPSE enables easy prediction of RVEF using TAPSE, an easily measurable M-mode index of echocardiography. TAPSE of 19.7 mm predicts reduced RVEF in PH patients with clinically acceptable sensitivity and specificity.     

Hypertrophic cardiomyopathy in cardiac CT: a validation study on the detection of intramyocardial fibrosis in consecutive patients

Hypertrophic Cardiomyopathy (HCM) confers a 4–5 %/year-risk for sudden cardiac death. Intramyocardial fibrosis (IF) is associated with this risk. The gold standard of IF visualization is cardiovascular magnetic resonance (CMR) with late gadolinium enhancement (LGE–CMR). In view of a number of CMR-limitations the hypothesis of this study was that late enhanced multi-slice computed tomography (leMDCT) enables demonstration of late enhancement (LE) indicating IF. In a prospective single-center validation study leMDCT research-scans were exclusively performed for IF-imaging in HCM-patients not including non-invasive coronary angiography during first-pass (64-slice; 80 kV; Iopromide, 150 mL, injected 7 min before scanning). Applying a 17-segment-polar-map short cardiac axis views (multiplanar reformations; 5 mm slice thickness) were analysed in order to exclude/detect, localize and measure LE practicing the manual quantification method if present. Finally, leMDCT and LGE–CMR data were unblinded for intermodal correlation. We included n = 24 patients consecutively (64.0 ± 14.5 years of age). LE was demonstrated by LGE–CMR in n = 14/24 patients (prevalence 58 %). Patient- and segment-based sensitivity in leMDCT was 100 and 68 %, respectively. In leMDCT tissue density of LE was 142 ± 51 versus 89.9 ± 19.3 HU in remote myocardium (p < 0.001). Signal-to-noise-ratio (SNR) and contrast-to-noise-ratio (CNR) appeared to be 7.3 ± 3.3 and 2.3 ± 1, respectively. Sizing of LE-area gave 2.2 ± 1.4 cm² in leMDCT versus 2.9 ± 2.4 cm² in LGE–CMR (r = 0.93). Intra-/interobserver variability was assessed with an accuracy of 0.36 cm² (r = 0.91) and 0.47 cm² (r = 0.82), respectively. In consecutive HCM patients leMDCT can reliably detect intramyocardial fibrosis marked by LE. In view of a comparatively low SNR and CNR leMDCT may alternatively be applied in case of CMR contraindications.     

实时三维超声心动图在三尖瓣下移畸形矫治术后右室重构评估中的应用

目的：探讨实时三维超声心动图（three-dimensional echocardiography,3DEcho）在三尖瓣下移畸形（Ebstein anomaly,EA）解剖矫治术后右室重构评估中的应用。 方法：回顾性分析2015年10月至2022年08月期间在中国医学科学院阜外医院住院行外科矫治术治疗的22例EA患者临床资料、3DEcho及心脏磁共振（cardiac magnetic resonance,CMR）指标。 结果：患者中位年龄30.7（14.1, 38.4）岁,中位随访时间22.9（6.5,35.6）月。3DEcho与CMR两种检查方法在基线右室舒张末容积指数（indexed right ventricular end-diastolic volume, RVEDVi）指标测值呈高度正相关(r = 0.908, P = 0.012);基线右室射血分数（right ventricular ejection fraction, RVEF）(r = 0.621, P = 0.002)、术后RVEF (r = 0.567, P = 0.009) ,两者测值均呈中度正相关,有统计学意义。术后与术前基线状态相比较,三尖瓣反流程度减轻【术后反流程度≥中度者3例（13.6%）vs.术前≥中度者20例（90.9%）,P<0.01】,RVEDVi较术前减小（98.4±54.8 vs. 188.5±114.5 ml/m2, P<0.01）,差异有统计学意义;术后整组RVEF变化无统计学意义（术后 41.2±7.9% vs. 术前44.6±6.7%, P=0.215）。 结论：3DEcho可准确评估EA患者右室容积及功能,并在术后随访评估右室重构中发挥重要作用。     

Dobutamine-induced increase of right ventricular contractility without increased stroke volume in adolescent patients with transposition of the great arteries: Evaluation with magnetic resonance imaging

Objective: Prognosis in patients with surgically corrected (Senning or Mustard) transposition of the great arteries (TGA) depends mainly on right ventricular (RV) function and RV functional reserve. We examined the role of dobutamine stress in the early detection of RV dysfunction in asymptomatic or slightly symptomatic patients with TGA using magnetic resonance imaging (MRI). Design and patients: Twelve asymptomatic or slightly symptomatic patients with chronic RV pressure overload, surgically corrected (Mustard or Senning) TGA (age 22.8 (±3.4) years; New York Heart Association (NYHA) class I/II) and nine age matched healthy volunteers (age 27.3 (±4.4) years) were included. MRI was applied both at baseline and during dobutamine stress (start dose 5 μg/kg/min to maximum dose 15 μg/kg/min) to determine RV and left ventricular (LV) stroke volumes (SV) and ejection fraction (EF). Results: At baseline only RVEF was significantly higher in controls than in patients (71 (±9) vs. 57 (±10)%, p < 0.001), other RV parameters were not significantly different between the two examined groups: RVSV (86 (±21) vs. 72 (±27) ml, p = ns), RV end-diastolic volume (EDV) (123 (±37) vs. 123 (±33) ml, p = ns), and heart rate (61 (±10) vs. 69 (±14) bpm, p = ns), respectively. During dobutamine stress RVEF increased significantly both in controls and patients (20 (±16) vs. 17 (±18)%, p < 0.01 and p < 0.02 vs. rest, respectively), but stress RVEF was significantly higher in controls than in patients (85 (±3) vs. 66 (±7)%, p < 0.0001). RVSV increased significantly in controls (22 (±19)%, p < 0.02), and there was no significant increase in RVSV in patients (?10 (±28)%, p = ns). The controls showed no change in RVEDV (2 (±17)%, p = ns), but in patients a significant decrease in RVEDV (?24 (±15)%, p < 0.001) was observed. Maximal heart rate was significantly higher in patients than in controls (122 (±20) vs. 101 (±14) bpm, p < 0.02). Conclusion: In asymptomatic or slightly symptomatic patients with surgically corrected TGA dobutamine had a positive inotropic effect on RV, but the increased contractility was not accompanied by an appropriate increase in SV. Our data suggest inadequate RV filling in this category of patients, possibly due to rigid atrial baffles and compromised atrial function or decreased compliance due to RV hypertrophy.     

Effect of atrial fibrillation ablation on myocardial function: insights from cardiac magnetic resonance feature tracking analysis

Restoration of sinus rhythm may result in an improvement of left heart function in patients with atrial fibrillation (AF). Cardiovascular magnetic resonance (CMR) feature tracking (FT) technique may help detect subtle wall-motion abnormalities. Consequently this study aimed to analyse existence and reversibility of subclinical cardiac dysfunction following atrial fibrillation ablation. 28 consecutive patients (mean age 61 years) with paroxysmal AF underwent pulmonary vein isolation. CMR imaging was done 3 (±3) days before and 3.4 (±1.1) months after ablation. Left heart function was determined by performing FT analysis. Statistical analysis included paired student’s t test, random effects metaanalysis to assess the cohort’s health status and Bland–Altman analysis. 17 patients (61 %) were free from AF at follow-up. Bland–Altman analysis showed good coefficients of variation. Of all 195 parameters, 27 changed (14 %):9 improved significantly (5 %), 12 worsened significantly (6 %), whereas 6 parameters worsened not significantly (3 %). 18 of 120 systolic parameters changed (15 %), 14 worsened (12 %), 4 improved (3 %). In 9 of 75 diastolic parameters, values changed (12 %): 5 improved (7 %) and 4 worsened (5 %). Meta-analysis revealed that our collective’s FT values at baseline didn’t differ significantly from healthy volunteers’ values [Q values of 0.01 (p value 0.921) and 1.499 (p value 0.221)]. AF patients undergoing ablation appear to have near normal cardiac wall motion, which does not improve following successful ablation. Feature tracking analysis is a reliable tool to determine treatment effects but is more likely to show positive findings if the population is unhealthy.     

Impact of right ventricular endocardial trabeculae on volumes and function assessed by CMR in patients with tetralogy of Fallot

The objective of this study was to assess the impact of right ventricular (RV) trabeculae and papillary muscles on measured volumes and function assessed by cardiovascular magnetic resonance imaging in patients with repaired tetralogy of Fallot. Sixty-five patients with repaired tetralogy of Fallot underwent routine cardiovascular magnetic resonance imaging. Endocardial and epicardial contours were drawn manually and included trabeculae and papillary muscles in the blood volume. Semi-automatic threshold-based segmentation software excluded these structures. Both methods were compared in terms of end-diastolic, end-systolic and stroke volume, ejection fraction and mass. Observer agreement was determined for all measures. Exclusion of trabeculae and papillary muscle in the RV blood volume decreased measured RV end-diastolic volume by 15 % (from 140 ± 35 to 120 ± 32 ml/m²) compared to inclusion, end-systolic volume by 21 % (from 74 ± 23 to 59 ± 20 ml/m²), stroke volume by 9 % (from 66 ± 16 to 60 ± 16 ml/m²) and relatively increased ejection fraction by 7 % (from 48 ± 7 to 51 ± 8 %) and end-diastolic mass by 79 % (from 28 ± 7 to 51 ± 10 g/m²), p < .01. Excluding trabeculae and papillary muscle resulted in an improved interobserver agreement of RV mass compared to including these structures (coefficient of agreement of 87 versus 78 %, p < .01). Trabeculae and papillary muscle significantly affect measured RV volumes, function and mass. Semi-automatic threshold-based segmentation software can reliably exclude trabeculae and papillary muscles from the RV blood volume.     

Left ventricular wall thickness in patients with hypertrophic cardiomyopathy: a comparison between cardiac magnetic resonance imaging and echocardiography

We assessed whether cardiac MRI (CMR) and echocardiography (echo) have significant differences measuring left ventricular (LV) wall thickness (WT) in hypertrophic cardiomyopathy (HCM) as performed in the clinical routine. Retrospectively identified, clinically diagnosed HCM patients with interventricular-septal (IVS) pattern hypertrophy who underwent CMR and echo within the same day were included. Left Ventricular WT was measured by CMR in two planes and compared to both echo and contrast echo (cecho). 72 subjects, mean age 50.7 ± 16.2 years, 68 % males. Interventricular septal WT by echo and CMR planes showed good to excellent correlation. However, measurements of the postero-lateral wall showed poor correlation. Bland–Altman plots showed greater maximal IVS WT by echo compared to CMR measurement [SAX = 1.7 mm (?5.8, 9.3); LVOT = 1.1 mm (?5.6, 7.8)]. Differences were smaller between cecho and CMR [SAX = 0.8 mm (?9.2, 10.8); LVOT = ?0.2 mm (?10.0, 9.6)]. Severity of WT by quartiles showed greater differences between echo and SAX CMR WT compared to cecho. Echocardiography typically measures greater WT than CMR, with the largest differences in moderate to severe hypertrophy. Contrast echocardiography more closely approximates CMR measurements of WT. These findings have potential clinical implications for risk stratification of subjects with HCM.     

实时三维超声心动图观察右心室收缩功能：动物实验与临床研究

目的 应用实时三维超声心动图右心室功能4D RV-Function(4D-RVF)分析法评价正常人及房间隔缺损患者右心室收缩功能.方法 ①对10只离体新鲜猪心行实时三维容积成像(RT-3DE),分别用4D-RVF和心尖长轴8平面法(AL 8-plane)分析软件测量其右心室容积,将所测值再分别与实测值比较.②对93例正常人(NOR)和15例房间隔缺损(atrial septal defect,ASD)患者行实时三维全容积成像,应用4D RV-Function分析软件测量右心室舒张末期容积(RV-EDV)、收缩末期容积(RVESV),每搏输出量(RVSV)及射血分数(RVEF).结果 ①离体猪心4D-RVF法所测值较心尖长轴8平面法所测值与实测值更接近.相关性更好,相关系数分别为r1=0.93,r2=0.82.② 4D-RVF法测量正常组(NOR)的右心室参数各指标:RVEDV为(90.57±28.27)m1,RVESV为(38.32±14.18)ml,RVSV为(52.25±16.86)ml,RVEF 为(57.96±6.85)%.③ASD患者右心室收缩功能减低.结论 实时三维超声心动图右心室功能(4D-RVF)分析法可准确评价右心室收缩功能.     

Assessment of the right ventricle with cardiovascular magnetic resonance at 7 Tesla

Background

Functional and morphologic assessment of the right ventricle (RV) is of clinical importance. Cardiovascular magnetic resonance (CMR) at 1.5T has become gold standard for RV chamber quantification and assessment of even small wall motion abnormalities, but tissue analysis is still hampered by limited spatial resolution. CMR at 7T promises increased resolution, but is technically challenging. We examined the feasibility of cine imaging at 7T to assess the RV.

Methods

Nine healthy volunteers underwent CMR at 7T using a 16-element TX/RX coil and acoustic cardiac gating. 1.5T served as gold standard. At 1.5T, steady-state free-precession (SSFP) cine imaging with voxel size (1.2x1.2x6) mm³ was used; at 7T, fast gradient echo (FGRE) with voxel size (1.2x1.2x6) mm³ and (1.3x1.3x4) mm³ were applied. RV dimensions (RVEDV, RVESV), RV mass (RVM) and RV function (RVEF) were quantified in transverse slices. Overall image quality, image contrast and image homogeneity were assessed in transverse and sagittal views.

Results

All scans provided diagnostic image quality. Overall image quality and image contrast of transverse RV views were rated equally for SSFP at 1.5T and FGRE at 7T with voxel size (1.3x1.3x4)mm³. FGRE at 7T provided significantly lower image homogeneity compared to SSFP at 1.5T. RVEDV, RVESV, RVEF and RVM did not differ significantly and agreed close between SSFP at 1.5T and FGRE at 7T (p=0.5850; p=0.5462; p=0.2789; p=0.0743). FGRE at 7T with voxel size (1.3x1.3x4) mm³ tended to overestimate RV volumes compared to SSFP at 1.5T (mean difference of RVEDV 8.2±9.3ml) and to FGRE at 7T with voxel size (1.2x1.2x6) mm³ (mean difference of RVEDV 9.3±8.6ml).

Conclusions

FGRE cine imaging of the RV at 7T was feasible and provided good image quality. RV dimensions and function were comparable to SSFP at 1.5T as gold standard.     

Right ventricular assessment at cardiac MRI: initial clinical experience utilizing an IS-SENSE reconstruction

Cardiac MR is considered the gold standard in assessing RV function. The purpose of this study is to evaluate the clinical utility of an investigational iterative reconstruction algorithm in the quantitative assessment of RV function. This technique has the potential to improve the clinical utility of CMR in the evaluation of RV pathologies, particularly in patients with dyspnea, by shortening acquisition times without adversely influencing imaging performance. Segmented cine images were acquired on 9 healthy volunteers and 29 patients without documented RV pathologies using conventional GRAPPA acquisition with factor 2 acceleration (GRAPPA 2), a spatio-temporal TSENSE acquisition with factor 4 acceleration (TSENSE 4), and iteratively reconstructed Sparse SENSE acquisition with factor 4 acceleration (IS-SENSE 4). 14 subjects were re-analyzed and intraclass correlation coefficients (ICC) were calculated and Bland–Altman plots generated to assess agreement. Two independent reviewers qualitatively scored images. Comparison of acquisition techniques was performed using univariate analysis of variance (ANOVA). Differences in RV EF, BSA-indexed ESV (ESVi), BSA-indexed EDV (EDVi), and BSA-indexed SV (SVi) were shown to be statistically insignificant via ANOVA testing. R² values for linear regression of TSENSE 4 and IS-SENSE 4 versus GRAPPA 2 were 0.34 and 0.72 for RV-EF, and 0.61 and 0.76 for RV-EDVi. ICC values for intraobserver and interobserver quantification yielded excellent agreement, and Bland–Altman plots assessing agreement were generated as well. Qualitative review yielded small, but statistically significant differences in image quality and noise between TSENSE 4 and IS-SENSE 4. All three techniques were rated nearly artifact free. Segmented imaging acquisitions with IS-SENSE reconstruction and an acceleration factor of 4 accurately and reliably quantitates RV systolic function parameters, while maintaining image quality. TSENSE-4 accelerated acquisitions showed poorer correlation to standard imaging, and inferior interobserver and intraobserver agreement. IS-SENSE has the potential to shorten cine acquisition times by 50?%, improving imaging options in patients with intermittent arrhythmias or difficulties with breath holding.