Cardiac Magnetic Resonance Ejection Fraction Research Articles

P452Prognostic performance of clinical presentation and cardiac magnetic resonance ejection fraction and late enhancement pattern at basal examination in acute myocarditis

P452Prognostic performance of clinical presentation and cardiac magnetic resonance ejection fraction and late enhancement pattern at basal examination in acute myocarditis

Relative Impact of Right Ventricular Electromechanical Dyssynchrony Versus Pulmonary Regurgitation on Right Ventricular Dysfunction and Exercise Intolerance in Patients After Repair of Tetralogy of Fallot.

BackgroundThe relative impact of right ventricular (RV) electromechanical dyssynchrony versus pulmonary regurgitation (PR) on exercise capacity and RV function after tetralogy of Fallot repair is unknown. We aimed to delineate the relative effects of these factors on RV function and exercise capacity.Methods and ResultsWe retrospectively analyzed 81 children with tetralogy of Fallot repair using multivariable regression. Predictor parameters were electrocardiographic QRS duration reflecting electromechanical dyssynchrony and PR severity by cardiac magnetic resonance. The outcome parameters were exercise capacity (percentage predicted peak oxygen consumption) and cardiac magnetic resonance ejection fraction (RV ejection fraction). To understand the relative effects of RV dyssynchrony versus PR on exercise capacity and RV function, virtual patient simulations were performed using a closed‐loop cardiovascular system model (CircAdapt), covering a wide spectrum of disease severity. Eighty‐one patients with tetralogy of Fallot repair (median [interquartile range {IQR}] age, 14.48 [11.55–15.91] years) were analyzed. All had prolonged QRS duration (median [IQR], 144 [123–152] ms), at least moderate PR (median [IQR], 40% [29%–48%]), reduced exercise capacity (median [IQR], 79% [68%–92%] predicted peak oxygen consumption), and reduced RV ejection fraction (median [IQR], 48% [44%–52%]). Longer QRS duration, more than PR, was associated with lower oxygen consumption and lower RV ejection fraction. In a multivariable regression analysis, oxygen consumption decreased with both increasing QRS duration and PR severity. CircAdapt modeling showed that RV dyssynchrony exerts a stronger limiting effect on exercise capacity and on RV ejection fraction than does PR, regardless of contractile function.ConclusionsIn both patient data and computer simulations, RV dyssynchrony, more than PR, appears to be associated with reduced exercise capacity and RV systolic dysfunction in patients after TOF repair.

Recoupling of right and left ventricle pump function after surgical ventricle restoration: a cardiac magnetic resonance study

To evaluate biventricular pump function after surgical ventricle restoration (SVR) using cardiac magnetic resonance (CMR). We retrospectively studied 39 patients who performed 1.5-T CMR before/after SVR acquiring short-axis ECG-gated cine sequences. End-diastolic, end-systolic, and stroke volume indexed to body surface area (EDVI, ESVI, and SVI), ejection fraction (EF), and their modification after SVR (∆) were obtained for right ventricle (RV) and left ventricle (LV). Wilcoxon signed rank test and Spearman correlation coefficient were used; EF reproducibility was estimated. Median LVEF increased from 24% [interquartile range (IQR) 19-31%] before SVR to 34% (IQR 29-43%) after SVR (P < 0.001). Median RVEF remained unchanged from 58% (IQR 48-66%) before SVR to 57% (IR 46-64%) after SVR (P = 0.743). The correlation between LVEF and RVEF was not significant before SVR (r = 0.182; P = 0.266) but significant after SVR (r = 0.445; P = 0.005). The ∆RVEF was positively correlated with ∆LVEF (r = 0.558; P < 0.001). ∆RVSVI was positively correlated with ∆LVSVI (r = 0.502; P = 0.001). LVEF reproducibility before SVR was 97% for both intra- and inter-reader reproducibility; RVEF reproducibility was 96 and 93%, respectively. SVR improved LV function without apparent impact on RV function. After SVR the two ventricles showed a functional recoupling. Reproducibility of CMR EF was excellent for both ventricles.

Global Longitudinal Strain and Global Circumferential Strain by Speckle-Tracking Echocardiography and Feature-Tracking Cardiac Magnetic Resonance Imaging: Comparison with Left Ventricular Ejection Fraction

Left ventricular (LV) ejection fraction (EF) is a routine clinical standard to assess cardiac function. Global longitudinal strain (GLS) and global circumferential strain (GCS) have emerged as important LV functional measures. The objective of this study was to determine the relationships of GLS and GCS by speckle-tracking echocardiography and featuring-tracking cardiac magnetic resonance (CMR) to CMR EF as a standard of reference in the same patients. A total of 73 consecutive patients aged 55±15years clinically referred for both CMR and echocardiography (EF range, 8%-78%) were studied. Routine steady-state free precession CMR images were prospectively analyzed offline using feature-tracking software for LV GLS, GCS, volumes, and EF. GLS was averaged from three standard longitudinal views and GCS from the mid-LV short-axis plane. Echocardiographic speckle-tracking was used from the similar imaging planes for GLS, GCS, LV volumes, and EF. Feature-tracking CMR strain was closely correlated with speckle-tracking strain in the same patients: GLS, r=-0.87; GCS, r=-0.92 (P<.0001). End-diastolic and end-systolic volumes and EF by feature-tracking CMR were significantly correlated with standard manual tracing of multiple CMR short-axis images (r=0.97, r=0.98, and r=0.97, P<.0001 for all). GLS and GCS by echocardiography and CMR feature-tracking were closely correlated with standard CMR EF: r=-0.85 and r=-0.95, respectively (P<.001). Global strain measures (in absolute values) were correlated with EF using the formula EF=3(GLS)+8% or EF=2.5(GCS)+8%. GLS and GCS by feature-tracking CMR analysis was a rapid means to obtain myocardial strain similar to speckle-tracking echocardiography. GLS and GCS were closely correlated with CMR EF in this patient series and may play a role in the clinical assessment of LV function.

Assessment of Right Ventricular Function Using Echocardiographic Speckle Tracking of the Tricuspid Annular Motion: Comparison with Cardiac Magnetic Resonance

Assessment of right ventricular (RV) function is difficult due to the complex shape of this chamber. Tricuspid annular plane systolic excursion (TAPSE) measured with M-mode echocardiography is frequently used as an index of RV function. However, its accuracy may be limited by ultrasound beam misalignment. We hypothesized that two-dimensional (2D) speckle tracking echocardiography (STE) could provide more accurate estimates of RV function. Accordingly, STE was used to quantify tricuspid annular displacement (TAD), from which RV longitudinal shortening fraction (LSF) was calculated. These STE derived indices were compared side-by-side with M-mode TAPSE measurements against cardiac magnetic resonance (CMR) derived RV ejection fraction (EF). Echocardiography (Philips iE33, four-chamber view) and CMR (Siemens, 1.5 T) were performed on the same day in 63 patients with a wide range of RV EF (23-70% by CMR). TAPSE was measured using M-mode echocardiography. TAD and RV LSF were obtained using STE analysis (QLAB CMQ, Philips). TAPSE, TAD and RV LSF values were compared with RV EF obtained from CMR short axis stacks. STE analysis required <15 seconds and was able to track tricuspid annular motion in all patients as verified visually. Correlation between RV EF and TAD (0.61 free-wall, 0.65 septal) was similar to that with M-mode TAPSE (0.63). However, STE-derived RV LSF showed a higher correlation with CMR EF (r = 0.78). RV LSF measurement by STE is fast and easy to obtain and provides more accurate evaluation of RV EF than the traditional M-mode TAPSE technique, when compared to CMR reference. (Echocardiography 2012;29:19-24).

Evaluation of cardiac iron load by cardiac magnetic resonance in thalassemia

To quantify myocardial iron stores by Cardiac Magnetic Resonance (CMR). Prospective cohort study. Thalassemia center in a teaching hospital. 60 transfusion dependant thalassemia major patients and 10 controls during 2008-2009. MRI T2* for cardiac iron load and cardiac functions was performed on a 1.5 Tesla Siemens Sonata machine using the thalassemia tools software. Ejection fraction (EF) was measured using standard CMR sequence and EF <56% considered as cardiac dysfunction. Quantification of iron deposition was categorized as T2* <10 milliseconds (ms) as high risk, 10-20 ms as intermediate risk and >20 ms as low risk. Simultaneous liver iron T2* values were categorized into normal i.e. >6.3 ms, mild iron overload 6.3-2.7 ms , moderate iron overload 2.7- 1.4 ms and severe iron overload <1.4 ms. Pretransfusion serum ferritin levels were simultaneously determined. Data was analyzed by paired and unpaired t test of mean. Of 60 patients, 50% had no cardiac siderosis; 33.3% had mild to moderate and while 16.7% had severe cardiac siderosis . In contrast, only 8.3% had normal liver iron values, 55.7% had mild to moderate and 36% had severe iron stores. The mean serum ferritin of all 60 cases was 3528.6 ± 1958.6 ng/mL. There was a statistically significant difference in the mean cardiac T2* of patients (23.45 ± 13.4 ms) as compared to controls (32.67 ± 2.68 ms) (P<0.01). Thalassemia patients had significantly higher cardiac iron stores as compared to controls. Serum ferritin and liver iron values did not correlate with cardiac iron values. Three of 10 patients <10 years showed evidence of myocardial siderosis.

Usefulness of Real-Time Three-Dimensional Echocardiography to Identify Right Ventricular Dysfunction in Patients With Congenital Heart Disease

Because right ventricular (RV) dysfunction predicts a poor outcome in patients with congenital heart disease (CHD), regular monitoring of RV function is indicated. To date, cardiac magnetic resonance (CMR) imaging has been the reference method. A more practical, more accessible, and accurate tool would be preferred. We defined normality regarding RV systolic function using healthy controls and tested the ability of real-time 3-dimensional echocardiographic (RT3DE) findings to identify patients with CHD with RV dysfunction. The cutoff values for the RV volumes and ejection fraction (EF) were derived from the CMR imaging findings from 41 healthy controls (mean age 27 +/- 8 years, 56% men). In 100 patients with varying CHDs (mean age 27 +/- 11 years, 65% men), both RT3DE data sets (iE33) and short-axis CMR imaging (1.5 T) were obtained within 2 hours. The RT3DE and CMR RV volumes and EF were calculated using commercially available software. Receiver operating characteristic curves were created to obtain the sensitivity and specificity of the RT3DE data to identify RV dysfunction. Applying the cutoff values derived from the healthy controls using the CMR data of patients with CHD, we identified 23 patients with an enlarged indexed end-diastolic volume, 29 patients with an enlarged indexed end-systolic volume, and 21 patients with an impaired RVEF. The best cutoff values predicting RV dysfunction using the RT3DE findings were identified (indexed end-diastolic volume >105 ml/m(2), indexed end-systolic volume >54 ml/m(2), and EF <43%). The RT3DE findings revealed 23 patients with impaired RVEF, with 95% sensitivity, 89% specificity, and a negative predictive value of 99%. In conclusion, real-time 3-dimensional echocardiography is a very sensitive tool to identify RV dysfunction in patients with CHD and could be applied clinically to rule out RV dysfunction or to indicate additional quantitative analysis of RV function.

Rapid Estimation of Left Ventricular Function Using Echocardiographic Speckle-Tracking of Mitral Annular Displacement

Left ventricular (LV) ejection fraction (EF) by transthoracic two-dimensional echocardiography is time-intensive and highly dependent on image quality. Mitral annular displacement (MAD) qualitatively correlates with EF and can be measured in patients with poor image quality and dropout. The authors hypothesized that speckle-tracking echocardiography (STE)-derived MAD could quantify EF accurately and tested this hypothesis using cardiac magnetic resonance (CMR) as a reference. One hundred eighteen patients undergoing clinical transthoracic echocardiography were screened, and 110 whose mitral annuli was sufficiently well-defined irrespective of LV endocardial visualization underwent CMR within 6 days (85 of 110 in 1 day). Reference CMR EF values were obtained using standard methodology. STE was used to track annular motion throughout the cardiac cycle in the apical 2-chamber and 4-chamber views. To establish the relationship between MAD and CMR EF and to obtain a formula to estimate EF from MAD, regression analysis was performed in a study group of 60 patients with a wide range of EFs. This formula was then used in an independent test group of 50 patients by comparing estimated MAD EF against CMR EF values using Pearson's correlation and Bland-Altman analyses. In the study group, STE MAD correlated highly with CMR EF and resulted in a formula relating MAD to EF. In the test group, estimated EF correlated well with CMR EF (4-chamber, R(2) = 0.64; 2-chamber, R(2) = 0.55), with near-zero bias and acceptable limits of agreement. Intraobserver and interobserver variability were between 5.8% and 12.7%. STE MAD is a clinically useful tool for quick, easy, robust, and accurate estimates of EF irrespective of LV endocardial definition.

Correlation Between Left Ventricular Diastolic Function and Ejection Fraction in Dilated Cardiomyopathy Using Magnetic Resonance Imaging With Late Gadolinium Enhancement

The distribution of left ventricular (LV) fibrosis and the percent fibrosis in patients with dilated cardiomyopathy (DCM) were evaluated using late gadolinium enhanced (LGE) MRI. Then the relation with the LV ejection fraction (EF) and deceleration time (DT), an index of diastolic function obtained using echocardiography, was investigated. LGEMRI at 20 min after intravenous injection of Gd-DTPA (0.15 +/-0.03 mmol/kg) was performed in 17 patients with DCM. The distribution of the LV enhanced area and LGE rate (%) were calculated. EF, as well as E/A ratio and DT were obtained using echocardiography. LGE was observed in 15 out of 17 patients (88%) and the enhanced region appeared to represent myocardial fibrosis. The LV fibrosis was often found in the intraventricular septum (IVS), but there were no differences in its distribution. The LGE rate (%) had a correlation between cardiac magnetic resonance ejection fraction (CMREF) (Y = 51.7 - 2.1X [R(2) = 0.23, P<0.001]) and DT (Y = 162.2 +12.0X [R(2) = 0.35, P<0.001]). The LV fibrosis is often found in the IVS with DCM. A correlation exists between LGE rate (%) to EF on CMR and DT on echocardiography in patients with DCM.

Comparison of echocardiographic (US) volumetry with cardiac magnetic resonance (CMR) imaging in transfusion dependent thalassemia major (TM)

BackgroundDespite advances in survival in patients with thalassemia major (TM) the most common cause of death is cardiac disease. Regular cardiac follow-up is imperative in order to identify and reverse pathology. Cardiac Magnetic Resonance (CMR) and Echocardiography (US) are applied in parallel to TM patients for cardiac evaluation and ongoing monitoring. A comparison between mutual features would be useful in order to assess the accuracy and reliability of the two methods, with a particular focus on routine US application. TM's special attributes offer an excellent opportunity for cardiac imaging research that has universal general purpose applications.Methods135 TM patients underwent US (Teichholz's M-mode formula – rapidly accessible means of measuring volumes and ejection fraction) and CMR volumetry. Paired-samples t-test, Passing & Badlock regression and Bland & Altman plot were used while comparing the common parameters between the CMR and the US.ResultsWe found that the US volumes were underestimated, especially the end-diastolic volume (p < 0.001). The end-systolic volume showed a borderline two-tailed probability (p ≈ 0.05). The correlation for the ejection fraction was acceptable (r = 0.60) without a statistically significant difference (p = 0.37) and the Bland Altman plot range was narrow (25.8%). There was a satisfactory correlation of the US' shortening fraction with CMR's ejection fraction (r = 0.58).ConclusionIn cases where cardiac wall movement abnormalities are absent, the US Teichholz's M-mode formula for volume measurements, though less sophisticated in comparison to the high resolution CMR technique, offers an adequate ejection fraction estimation for routine use, especially when monitoring gross alterations in cardiac function over time, and is easy to perform.

Effect of cardiac disease history on gated blood pool SPECT LV measurement accuracy

Background: Recently software has become available for the routine analysis of left ventricular (LV) end-diastolic volume (EDV) and ejection fraction (EF) from gated blood pool SPECT (GBPS) data. This investigation examined whether accuracy of GBPS measurements, using cardiac magnetic resonance (CMR) imaging as the standard, are influenced by unusual LV shapes, as would be expected for patients with prior MI. Methods: LV functional parameters were measured for 28 subjects (age=58±12 years; 85% male, 13 with prior MI (MI) and 15 with non-ischemic cardiomyopathy (CM) by GBPS, planar-GBP and by true-FISP CMR. GBPS calculations from a count-threshold algorithm (BP-SPECT, Columbia University, New York, NY), and a surface gradient algorithm (QBS, Cedars-Sinai Medical Center, Los Angeles, CA) were evaluated. Results: By linear regression analysis BP-SPECT, QBS and planar-GBP EF's correlated similarly with CMR (r=0.92, 0.88 and 0.90, respectively) and both GBPS methods correlated similarly versus CMR for EDV (r=0.88 and 0.89, respectively). By the paired t-test, CMR EF's (38%±17%) were not different from BP-SPECT, QBS or planar-GBP (44%±18%, 36%±19%, and 38%±16%, respectively) for MI and CM patients. BP-SPECT and QBS EDV's were found to be significantly lower than CMR for MI patients (159±51 ml and 140±69 ml versus 207±70 ml) but not for CM patients (223±108 ml and 206±111 ml versus 274±109 ml). Conclusion: GBPS LV function measurements closely parallel those of CMR and planar-GBP, but volume accuracy is influenced by presence or absence of prior myocardial infarction.