Estimation Of Ejection Fraction Research Articles

Ejection fraction in myocardial perfusion imaging assessed with a dynamic phantom: comparison between IQ-SPECT and LEHR

BackgroundDevelopments in single photon emission tomography instrumentation and reconstruction methods present a potential for decreasing acquisition times. One of such recent options for myocardial perfusion imaging (MPI) is IQ-SPECT. This study was motivated by the inconsistency in the reported ejection fraction (EF) and left ventricular (LV) volume results between IQ-SPECT and more conventional low-energy high-resolution (LEHR) collimation protocols. IQ-SPECT and LEHR quantitative results were compared while the equivalent number of iterations (EI) was varied. The end-diastolic (EDV) and end-systolic volumes (ESV) and the derived EF values were investigated.A dynamic heart phantom was used to produce repeatable ESVs, EDVs and EFs. Phantom performance was verified by comparing the set EF values to those measured from a gated multi-slice X-ray computed tomography (CT) scan (EFTrue). The phantom with an EF setting of 45, 55, 65 and 70% was imaged with both IQ-SPECT and LEHR protocols. The data were reconstructed with different EI, and two commonly used clinical myocardium delineation software were used to evaluate the LV volumes.ResultsThe CT verification showed that the phantom EF settings were repeatable and accurate with the EFTrue being within 1% point from the manufacture’s nominal value. Depending on EI both MPI protocols can be made to produce correct EF estimates, but IQ-SPECT protocol produced on average 41 and 42% smaller EDV and ESV when compared to the phantom’s volumes, while LEHR protocol underestimated volumes by 24 and 21%, respectively. The volume results were largely similar between the delineation methods used.ConclusionsThe reconstruction parameters can greatly affect the volume estimates obtained from perfusion studies. IQ-SPECT produces systematically smaller LV volumes than the conventional LEHR MPI protocol. The volume estimates are also software dependent.

Can an Offsite Expert Remotely Evaluate the Visual Estimation of Ejection Fraction via a Social Network Video Call?

We aimed to investigate whether an offsite expert could effectively evaluate visually estimated ejection fraction (EF) while watching and guiding the echocardiographic procedure of an onsite novice practitioner using a social network video call. Sixty patients presenting to the intensive care unit and requiring echocardiography between October and November 2016 were included. Sixty novice sonographers without any previous experience of echocardiography participated. Prior to the procedure, the onsite cardiologist completed the echocardiography and determined the EF using the modified Simpson's method (reference value). Then, the novice practitioner performed the echocardiography again with the offsite expert's guidance via a social network video call. The EF was visually estimated by the offsite expert while watching the ultrasound video on the smartphone display. Spearman's rank correlation and Bland-Altman plot analysis were conducted to assess the agreement between the two methods. There was excellent agreement between the two methods, with a correlation coefficient of 0.94 (p<0.001). The Bland-Altman plot showed that the average bias was -3.05, and the limit of agreement (-10.3 to 4.2) was narrow. The offsite expert was able to perform an accurate visual estimation of ejection fraction remotely via a social network video call by mentoring the onsite novice sonographer. ClinicalTrials.gov Identifier: NCT02960685.

Enhancing ejection fraction measurement through 4D respiratory motion compensation in cardiac PET imaging

ECG gated cardiac PET imaging measures functional parameters such as left ventricle (LV) ejection fraction (EF), providing diagnostic and prognostic information for management of patients with coronary artery disease (CAD). Respiratory motion degrades spatial resolution and affects the accuracy in measuring the LV volumes for EF calculation. The goal of this study is to systematically investigate the effect of respiratory motion correction on the estimation of end-diastolic volume (EDV), end-systolic volume (ESV), and EF, especially on the separation of normal and abnormal EFs. We developed a respiratory motion incorporated 4D PET image reconstruction technique which uses all gated-frame data to acquire a motion-suppressed image. Using the standard XCAT phantom and two individual-specific volunteer XCAT phantoms, we simulated dual-gated myocardial perfusion imaging data for normally and abnormally beating hearts. With and without respiratory motion correction, we measured the EDV, ESV, and EF from the cardiac-gated reconstructed images. For all the phantoms, the estimated volumes increased and the biases significantly reduced with motion correction compared with those without. Furthermore, the improvement of ESV measurement in the abnormally beating heart led to better separation of normal and abnormal EFs. The simulation study demonstrated the significant effect of respiratory motion correction on cardiac imaging data with motion amplitude as small as 0.7 cm. The larger the motion amplitude the more improvement respiratory motion correction brought about on the EF measurement. Using data-driven respiratory gating, we also demonstrated the effect of respiratory motion correction on estimating the above functional parameters from list mode patient data. Respiratory motion correction has been shown to improve the accuracy of EF measurement in clinical cardiac PET imaging.

Fully-automatic left ventricular segmentation from long-axis cardiac cine MR scans

With an increasing number of large-scale population-based cardiac magnetic resonance (CMR) imaging studies being conducted nowadays, there comes the mammoth task of image annotation and image analysis. Such population-based studies would greatly benefit from automated pipelines, with an efficient CMR image analysis workflow. The purpose of this work is to investigate the feasibility of using a fully-automatic pipeline to segment the left ventricular endocardium and epicardium simultaneously on two orthogonal (vertical and horizontal) long-axis cardiac cine MRI scans. The pipeline is based on a multi-atlas-based segmentation approach and a spatio-temporal registration approach. The performance of the method was assessed by: (i) comparing the automatic segmentations to those obtained manually at both the end-diastolic and end-systolic phase, (ii) comparing the automatically obtained clinical parameters, including end-diastolic volume, end-systolic volume, stroke volume and ejection fraction, with those defined manually and (iii) by the accuracy of classifying subjects to the appropriate risk category based on the estimated ejection fraction. Automatic segmentation of the left ventricular endocardium was achieved with a Dice similarity coefficient (DSC) of 0.93 on the end-diastolic phase for both the vertical and horizontal long-axis scan; on the end-systolic phase the DSC was 0.88 and 0.85, respectively. For the epicardium, a DSC of 0.94 and 0.95 was obtained on the end-diastolic vertical and horizontal long-axis scans; on the end-systolic phase the DSC was 0.90 and 0.88, respectively. With respect to the clinical volumetric parameters, Pearson correlation coefficient (R) of 0.97 was obtained for the end-diastolic volume, 0.95 for end-systolic volume, 0.87 for stroke volume and 0.84 for ejection fraction. Risk category classification based on ejection fraction showed that 80% of the subjects were assigned to the correct risk category and only one subject (< 1%) was more than one risk category off. We conclude that the proposed automatic pipeline presents a viable and cost-effective alternative for manual annotation.

Predictors of serious arrhythmic events in patients with nonischemic heart failure.

Risk stratification of serious arrhythmic events in patients with nonischemic heart failure (HF), beyond estimates of left ventricular ejection fraction (LVEF), remains an important clinical challenge. This study aims to determine the clinical value of different noninvasive and invasive tests as predictors of serious arrhythmic events in patients with nonischemic HF. A prospective observational study was conducted including 106 nonischemic HF patients who underwent a comprehensive clinical and laboratory evaluation including two-dimensional echocardiography, 24-h Holter monitoring, cardiopulmonary exercise testing (CPX), and an invasive electrophysiological study. The study's primary end-point was either syncope, appropriate therapy by implantable cardioverter-defibrillators, or sudden cardiac death. During a mean follow-up of 704 ± 320days, the primary end-point occurred in 15 patients (14.2%). In multivariable analysis, LV end-diastolic diameter >73mm (hazard ratio [HR] 3.7; p = 0.016), exercise periodic breathing (EPB) on CPX (HR 2.88; p = 0.045), and non-sustained ventricular tachycardia (NSVT) ≥10 beats (HR 8.2; p < 0.01) remained independently associated with serious arrhythmic events. The positive predictive value of the presence of two of these predictors ranged from 44 to 100%. The absence of all three factors (n = 65, 61% of the sample) identified a subset of patients with low risk of future arrhythmic events, with a negative predictive value of 96.9%. In this cohort study of nonischemic HF patients, LV dimension, EPB, and NSVT ≥10 beats were independent predictors of serious arrhythmic events. The presence or absence of these characteristics identified sub-groups of high and low risk of serious arrhythmic events, respectively.

Real-time three-dimensional speckle tracking echocardiography: technical aspects and clinical applications

Real-time three-dimensional speckle tracking echocardiography: technical aspects and clinical applications Regina Sorrentino,&nbsp;Roberta Esposito,&nbsp;Enrica Pezzullo,&nbsp;Maurizio Galderisi Department of Advanced Biomedical Sciences, Interdepartmental Laboratory of Cardiac Imaging, Federico II University Hospital, Naples, Italy Abstract: Three-dimensional speckle tracking echocardiography (3D STE) is a novel technique for the quantification of cardiac deformation based on tracking of ultrasonic speckles in gray scale full-volume 3D images. Developments in ultrasound technologies have made 3D speckle tracking widely available. Two-dimensional echocardiography has intrinsic limitations regarding estimation of left ventricular (LV) volumes, ejection fraction, and LV mechanics, due to its inherent foreshortening errors and dependency on geometric models. The development of 3D echocardiography has improved reproducibility and accuracy. Data regarding the feasibility, accuracy, and clinical applications of 3D STE are rapidly assembling. From the tracking results, 3D STE derives several parameters, including longitudinal, circumferential and radial strain, as well as a combined assessment of longitudinal and circumferential strain, termed area strain. 3D STE can also quantify LV rotational movements such as rotation, twist, and torsion. 3D STE provides a better insight on global and regional myocardial deformation. Main applications include detection of subclinical myocardial involvement in heart failure, arterial hypertension, dyssynchrony, and ischemic heart disease. Emerging areas of application include a large spectrum of heart-involving systemic conditions, such as prediction of rejection in heart transplant patients, early detection of cardiotoxicity in patients receiving chemotherapy for cancer, and deeper physiological understanding of LV contraction mechanics in different types of athletes. Aim of this review is to discuss background, technical acquisition and processing aspects as well as recognized and developing clinical applications of this emerging ultrasound technology. Keywords: speckle tracking echocardiography, three-dimensional echocardiography, myocardial deformation, validation, clinical applications

The implication of tissue Doppler echocardiography and cardiopulmonary exercise in early detection of cardiac dysfunction in systemic lupus erythematosus patients.

Systemic lupus erythematosus (SLE) can present limitations to exercise capacity and quality of life (QoL) because of various clinical conditions, such as pulmonary disease or heart disease. Tissue Doppler echocardiography (TDE) offers the promise of an objective measurement to quantify regional and global ventricular function through the assessment of myocardial velocity data. This study aimed to assess the intensity of left ventricular (LV) and right ventricular (RV) systolic and diastolic dysfunction in SLE patients by means of TDE and cardiopulmonary exercise (CPX) testing to determine their impact on QoL. Overall, 56 SLE patients within two tertiary healthcare centers as well as 50 healthy controls were examined with TDE after the exclusion of cardiovascular risk factors. TDE was performed for maximal systolic (S), early diastolic (E'), and late diastolic (A') velocities of the mitral and tricuspid annulus. Pulsed wave (PW) Doppler of mitral and tricuspid valve inflow was performed in addition to the estimation of the left ventricle ejection fraction and assessment of right ventricle systolic function by tricuspid annular plane systolic excursion (TAPSE). Disease activity was assessed by the Systemic Lupus Activity Measure (SLAM), and the damage index was assessed by the Systemic Lupus International Collaborating Clinics (SLICC)/American College of Rheumatology (ACR) Damage Index (SDI). CPX tests according to the modified Bruce protocol were performed. SLE patients in both subgroups had more or less similar laboratory data and statistically higher values of ESR, CRP, and anticardiolipin (aCL) antibodies compared to the control group. LV function showed statistically insignificant EF compared to the control group, being lower in the patient group. Tissue Doppler image revealed that E' and A' of the mitral annulus were lower in the patient group than in the control group. Concerning RV, TAPSE in the patient group was statistically lower than in the control group, and there was a statistical difference between SLE groups Ia and Ib; also, S wave was lower in group Ib than in group Ia. RV diastolic dysfunction in the form of lower E' and A' values was observed for the SLE group compared to the control group, especially in the medial annulus of the tricuspid valve. A higher A wave velocity with PWD of mitral and tricuspid inflows was observed in the patient group compared to the control group. SLE patients have an increased prevalence of subclinical systolic and diastolic LV and RV dysfunction. This result advocates for regular follow-up and early screening of SLE patients. Accordingly, treatment focused on improving diastolic heart function may have a role in enhancing QoL and improving the prognosis of SLE patients.

Platelet distribution width predicts left ventricular dysfunction in patients with acute coronary syndromes treated with percutaneous coronary intervention.

The role of platelets in the pathophysiology of acute coronary syndromes (ACS) is undeniable, but precise relationships between platelet activity and treatment outcomes are a matter of continuant investigation. Among platelet indices, mean platelet volume (MPV) has proven to be a valuable predicting factor in cardiac patients. However, platelet distribution width (PDW) is reported to be a more specific marker of platelet reactivity. Thus, application of PDW in risk stratification of ACS treatment is an up-to-date subject of research. PDW values in the assessment of left ventricular (LV) function have not been previously studied. The aim of the study was to evaluate whether admission PDW can predict LV systolic function in patients with ACS treated with stent implantation. On-admission PDW was measured in 278 consecutive patients with diagnosis of ACS, who underwent stent(s) implantation. Echocardiogram with LV ejection fraction (LVEF) estimation was performed within 24 h of percutaneous coronary intervention. Additionally, patients were under one-year follow-up, and one-year all-cause mortality was assessed. According to receiver-operating characteristics (ROC) analysis, a PDW value greater than 12.8 fL could predict LVEF ≤ 35% with sensitivity of 81% and specificity of 39% (AUC 0.614; p = 0.0177). Only a trend was noted in ROC for PDW and one-year mortality (AUC 0.608; p = 0.0815). Multivariate logistic regression analysis has shown that the PDW parameter correlates independently with both systolic heart failure with LVEF ≤ 35% (PDW cut-off: 12.8 fL, OR 2.8107, CI 1.1401-6.9293, p = 0.0248) and one-year mortality (PDW cut-off: 16 fL, OR 2.6750, CI 1.0190-7.0225, p = 0.0457). Admission PDW may serve as a simple and widely available predictor of impaired LV function in patients with ACS. Association between PDW and mortality needs to be confirmed in larger studies.

Estimation of left ventricular ejection fraction with low-dose gated tomographic radionuclide angiography using cadmium-zinc-telluride gamma camera in patients receiving cardio-toxic chemotherapy: A dramatic radiation reduction.

e14030Background: Tomographic radionuclide angiography (TRA) is a simple non-invasive procedure which can monitor left ventricular ejection fraction (LVEF) with automatic processing software, resul...

Estimation of Ejection Fraction with Ventriculography Versus Echocardiography in Patients Referred for Cardiac Surgery

Aim : The aim of this study was to compare the estimation of ejection fraction (EF) by ventricuography (VG) and echocardiography (ECHO) in patients referred for surgery and to validate the results by comparison with other published data. Methods : One hundred patients who underwent VG prior to surgery were subjected to a trans-thoracic ECHO. Radiographers calculated the EF by tracing the outer border of the ventriculogram during systole and diastole. A single cardiologist, who was blinded to the angiogram result, measured EF during trans-thoracic ECHO using the biplane Simpson’s method. Results : EF was significantly higher by VG versus ECHO for the whole group (67.9±13.2 vs 55.7±8.5, p = 0.000). In 81 patients the EF estimated at VG was higher than that calculated at ECHO (71.7±10.2 vs 55.9±7.2, p = 0.000). In 19 patients the EF estimated at VG was lower than that calculated at ECHO, but the difference was not significant (51.8±12.9 by VG vs 55.4±12.8, p= 0.387). In 13 patients, with an EF less than 50% on VG, the correlation with ECHO was very good (42.0±9.0 vs 42.0±8.3, p= 0.995). Two patients with an EF fraction under 30% had similar measurements by VG and ECHO. The EF range as measured by ECHO was consistent with published data. Conclusion : Ventriculography overestimates EF when compared with ECHO. When EF is less than 50% on VG, ECHO findings were similar. The value of ventriculography in patients referred for cardiac surgery is now being brought into question when ECHO, a better and less invasive test that measures EF, is available.

13N-AMMONIA PET-DERIVED VENTRICULAR SYNCHRONY CORRELATES WITH MYOCARDIAL PERFUSION RESERVE BETTER THAN LEFT VENTRICULAR EJECTION FRACTION: A STUDY IN INFARCTED PATIENTS

Background: PET myocardial perfusion allows myocardial perfusion reserve (MPR) quantification as well as left ventricular ejection fraction (LVEF) and synchrony estimation through phase analysis. There is a relationship between MPR and LVEF and both have proven prognostic value in coronary artery disease (CAD). A relation between angiographic CAD extent and post-stress synchrony has been proposed with SPECT. We used 13N-ammonia PET to evaluate the relationship between MPR and ventricular synchrony in patients with a previous infarction and secondarily, to compare it to the relation MPR-LVEF. Methods: We studied 63 patients (64.4±11.1years) with a previous myocardial infarction with a rest/adenosine-stress 13N-ammoniaPET. Demographics and cardiovascular history were retrieved. MPR was calculated dividing the stress by the rest blood flow. Synchrony was evaluated through Entropy, systolic function through LVEF and the area of previous infarction through the resting total perfusion defect (TPD). Two multiple regressions were done: the first used Entropy as dependent variable and MPR, TPD and clinical variables as predictors; in the second LVEF replaced the dependent variable. The standardized regression coefficients were compared. Results: There were 49 males and 14 females, 39% with diabetes, 54% with hypertension, 54% with dyslipidemia, 42% of smokers and 44% with chest pain. Mean MPR=2.14±0.79, mean TPD=15.8%±11.2, mean LVEF=49%±17 and mean Entropy=53.4%±11.8. The first regression showed a significant independent relation between MPR and Entropy (β=-.384, p=0.006). This relation was greater than the one between MPR and LVEF (β=.292, p=0.013) in the second regression. In both, TPD (p=0.021, p=0.001) and gender (p=0.041, p=0.001) showed a significant correlation with the dependent variables. Conclusions: In patients with a previous myocardial infarction, PET-measured MPR significantly correlates to ventricular synchrony independently from the area of infarction. This correlation is stronger than the one between MPR and LVEF. Our results warrant further research into the added prognostic value of PET-measured ventricular synchrony and entropy in the setting of CAD.

Comparative analysis of full-time, half-time, and quarter-time myocardial ECG-gated SPECT quantification in normal-weight and overweight patients

BackgroundThe introduction of a camera-based dose-reduction strategy in myocardial perfusion imaging (MPI) clinical setting entails the definition of objective and reproducible criteria for establishing the amount of activity to be injected. AimThe aim is to evaluate the impact of count statistics on the estimation of summed-scores (SS), end-diastolic volume (EDV), end-systolic volume (ESV), and ejection fraction (EF). MethodsData rest/stress ECG-gated SPECT (2-day protocol and 8 MBq·kg−1) were acquired with Bright View gamma camera and Astonish algorithm for 40 normal-weight and 40 overweight patients. Assuming that count statistics of shorter acquisition time may simulate that of lower injected activity, three simultaneous scans (full-time, half-time, and quarter-time scans) were started at the same time but with different acquisition time/projection (30, 15 and 8 seconds). ResultsA significant difference between SS values of half-time and quarter-time stress scans was found for overweight group (P = .006). Post hoc test showed significant differences for ESV (P < .05), EDV (P < .01) and EF (P < .05) between half-time and quarter-time scans for both patient groups. ConclusionsThe reduction of the count-statistics to a quarter of the MPI reference influenced negatively the quantification in overweight patients. The decrease of radiopharmaceutical activity to 25% of the reference seems practicable for normal-weight patients, while it is more appropriate an activity reduction limited to 50% for overweight and obese patients.

Anthracycline or trastuzumab-related cardiotoxicity: do we have a predictive biomarker?

Chemotherapy-induced cardiotoxicity, is a well-known and potentially serious complication strongly impacting the quality of life and overall survival of breast cancer patients. The current diagnostic approach to detect cardiac damage is the estimation of left ventricular ejection fraction by echocardiography. However, this approach exhibits less sensitivity toward early prediction of cardiomyopathy, not allowing for preventive strategies. Measurement of serum cardiac-specific biomarkers can be a valid diagnostic tool for identifying patients prone to developing cardiotoxocity and in whom closer cardiac monitoring and preventive strategies are pivotal. In this article, we review work done on biomarkers in recent years, with an emphasis on troponin and B-type natriuretic peptide, which are currently the most studied in this field. We also briefly discuss current and emerging imaging techniques for early detection of cardiomyopathy.

The influence of cardiac function on coronary arterial enhancement at coronary computed tomography angiography: A cross-sectional study.

Background:The purpose of this study was to evaluate the influence of ejection fraction (EF) on peak aortic time (PAT) and peak aortic enhancement (PAE) during coronary computed tomography angiography (CTA).Materials and Methods:One-hundred and twenty patients (64 men, 56 women) underwent measurement of coronary CTA with a measurement of EF within 3 months of coronary CTA. Pearson's correlation coefficient analysis was used to investigate the relationships between EF, PAT and PAE, and peak attenuation of all coronary arteries.Results:The range of EF was (25%–70%) (mean: 55 ± 7.7). The range of PAT and PAE of ascending aorta on bolus test was 13–31 s (mean: 19.3 ± 2) and 153–435 HU (mean: 235 ± 40.6), respectively. Mean peak attenuation of ascending aorta, right coronary artery, left coronary artery, left circumflex artery, and left anterior descending were (561 ± 119), (476 ± 109), (505 ± 108), (467 ± 113), and (473 ± 104), respectively. There was a negative correlation between EF and PAT (r = −0.266, P = 0.003); however, there was no significant correlation between EF and PAE (r = −0.027, P = 0.767). In addition, there was no significant correlation between EF and the peak attenuation of coronary arteries.Conclusion:PAT was related to EF, but there was no relationship between PAE and EF. One of the explanation is that the left ventricular EF used for our study was assessed with echocardiography which is used roughly estimation of EF with interval of 5%–10% and may cause confounding results.

Beyond ejection fraction: an integrative approach for assessment of cardiac structure and function in heart failure.

Left ventricular ejection fraction (LVEF) has been the central parameter used for diagnosis and management in patients with heart failure. A good predictor of adverse outcomes in heart failure when below ∼45%, LVEF is less useful as a marker of risk as it approaches normal. As a measure of cardiac function, ejection fraction has several important limitations. Calculated as the stroke volume divided by end-diastolic volume, the estimation of ejection fraction is generally based on geometric assumptions that allow for assessment of volumes based on linear or two-dimensional measurements. Left ventricular ejection fraction is both preload- and afterload-dependent, can change substantially based on loading conditions, is only moderately reproducible, and represents only a single measure of risk in patients with heart failure. Moreover, the relationship between ejection fraction and risk in patients with heart failure is modified by factors such as hypertension, diabetes, and renal function. A more complete evaluation and understanding of left ventricular function in patients with heart failure requires a more comprehensive assessment: we conceptualize an integrative approach that incorporates measures of left and right ventricular function, left ventricular geometry, left atrial size, and valvular function, as well as non-imaging factors (such as clinical parameters and biomarkers), providing a comprehensive and accurate prediction of risk in heart failure.

Evaluation of tricuspid annular plane systolic excursion measured with cardiac MRI in children with tetralogy of Fallot.

Aneurysmal dilation of the right ventricular outflow tract complicates assessment of right ventricular function in patients with repaired tetralogy of Fallot. Tricuspid annular plane systolic excursion is commonly used to estimate ejection fraction. We hypothesised that tricuspid annular plane systolic excursion measured by cardiac MRI approximates global and segmental right ventricular function, specifically right ventricular sinus ejection fraction, in children with repaired tetralogy of Fallot. Tricuspid annular plane systolic excursion was measured retrospectively on cardiac MRIs in 54 patients with repaired tetralogy of Fallot. Values were compared with right ventricular global, sinus, and infundibular ejection fractions. Tricuspid annular plane systolic excursion was indexed to body surface area, converted into a fractional value, and converted into published paediatric Z-scores. Tricuspid annular plane systolic excursion measurements had good agreement between observers. Right ventricular ejection fraction did not correlate with the absolute or indexed tricuspid annular plane systolic excursion and correlated weakly with fractional tricuspid annular plane systolic excursion (r=0.41 and p=0.002). Segmental right ventricular function did not appreciably improve correlation with any of the tricuspid annular plane systolic excursion measures. Paediatric Z-scores were unable to differentiate patients with normal and abnormal right ventricular function. Tricuspid annular plane systolic excursion measured by cardiac MRI correlates poorly with global and segmental right ventricular ejection fraction in children with repaired tetralogy of Fallot. Tricuspid annular plane systolic excursion is an unreliable approximation of right ventricular function in this patient population.

Defining the real-world reproducibility of visual grading of left ventricular function and visual estimation of left ventricular ejection fraction: impact of image quality, experience and accreditation

Left ventricular function can be evaluated by qualitative grading and by eyeball estimation of ejection fraction (EF). We sought to define the reproducibility of these techniques, and how they are affected by image quality, experience and accreditation. Twenty apical four-chamber echocardiographic cine loops (Online Resource 1–20) of varying image quality and left ventricular function were anonymized and presented to 35 operators. Operators were asked to provide (1) a one-phrase grading of global systolic function (2) an “eyeball” EF estimate and (3) an image quality rating on a 0–100 visual analogue scale. Each observer viewed every loop twice unknowingly, a total of 1400 viewings. When grading LV function into five categories, an operator’s chance of agreement with another operator was 50 % and with themself on blinded re-presentation was 68 %. Blinded eyeball LVEF re-estimates by the same operator had standard deviation (SD) of difference of 7.6 EF units, with the SD across operators averaging 8.3 EF units. Image quality, defined as the average of all operators’ assessments, correlated with EF estimate variability (r = −0.616, p < 0.01) and visual grading agreement (r = 0.58, p < 0.01). However, operators’ own single quality assessments were not a useful forewarning of their estimate being an outlier, partly because individual quality assessments had poor within-operator reproducibility (SD of difference 17.8). Reproducibility of visual grading of LV function and LVEF estimation is dependent on image quality, but individuals cannot themselves identify when poor image quality is disrupting their LV function estimate. Clinicians should not assume that patients changing in grade or in visually estimated EF have had a genuine clinical change.Electronic supplementary materialThe online version of this article (doi:10.1007/s10554-015-0659-1) contains supplementary material, which is available to authorized users.

Gated blood pool SPECT: The estimation of right ventricular volume and function is algorithm dependent in a clinical setting

BackgroundGated blood pool SPECT (GBPS) requires further validation for the assessment of the right ventricle (RV). This study evaluated three algorithms: BP-SPECT, QBS, and TOMPOOL (results are referred using this order). We compared (1) their “quantitative-accuracy”: estimation of RV ejection fraction (EF), end-diastolic volume (EDV), and cardiac output (CO); (2) their “qualitative-accuracy”: threshold values allowing diagnosing an impairment of the RV function; (3) their reproducibility: inter-observer relative variability (IOV). Methods and ResultsForty-eight consecutive patients underwent GBPS. Recommended reference standards were used: cardiac magnetic resonance imaging (CMR) (EDV, EF, n = 48), catheter measurements from thermodilution (TD) (CO, n = 25). (1) “Quantitative-accuracy”: r = 0.42, 0.30, 0.42 for RVEF (CMR); r = 0.69, 0.77, 0.53 for RVEDV (CMR); 0.32, 0.36, 0.52 for RCO (TD). (2) “Qualitative-accuracy”: optimal thresholds were 54.7%, 38.5%, 45.2% (AUC: 0.83, 0.80, 0.79) for RVEF; 229, 180, 94 mL (AUC: 0.83, 0.81, 0.81) for RVEDV; 4.1, 4.4, 2.6 L·minute−1 (AUC: 0.73, 0.77, 0.80) for RCO. (3) Reproducibility: IOV was 5% ± 6%, 8% ± 12%, 17% ± 18% for RVEF; 6% ± 8%, 4% ± 4%, 21% ± 18% for RVEDV; 8% ± 8%, 11% ± 15%, 24% ± 20% for RCO. ConclusionDiagnostic accuracies are similar. A CMR-based calibration is required for a quantitative-analysis (cautious interpretation) or an accurate qualitative analysis (thresholds must be adjusted). Automatic procedures (BP-SPECT, QBS) offer the best compromise accuracy/reproducibility.

Impact of Point-of-Care Ultrasound Training on Surgical Residents’ Confidence

Point-of-care ultrasound (POCUS) is a vital tool for diagnosis and management of critically ill patients, particularly in resource-limited settings where access to diagnostic imaging may be constrained. We aimed to develop a novel POCUS training curriculum for surgical practice in the United States and in resource-limited settings in low- and middle-income countries and to determine its effect on surgical resident self-assessments of efficacy and confidence. We conducted an observational cohort study evaluating a POCUS training course that comprised 7 sessions of 2 hours each with didactics and proctored skills stations covering ultrasound applications for trauma (Focused Assessement with Sonography for Trauma (FAST) examination), obstetrics, vascular, soft tissue, regional anesthesia, focused echocardiography, and ultrasound guidance for procedures. Surveys on attitudes, prior experience, and confidence in point-of-care ultrasound applications were conducted before and after the course. General Surgery Training Program in Seattle, Washington. A total of 16 residents participated in the course; 15 and 10 residents completed the precourse and postcourse surveys, respectively. The mean composite confidence score from pretest compared with posttest improved from 23.3 (±10.2) to 37.8 (±6.7). Median confidence scores (1-6 scale) improved from 1.5 to 5.0 in performance of FAST (p < 0.001). Residents reported greater confidence in their ability to identify pericardial (2 to 4, p = 0.009) and peritoneal fluid (2 to 4.5, p < 0.001), to use ultrasound to guide procedures (3.5 to 4.0, p = 0.008), and to estimate ejection fraction (1 to 4, p = 0.004). Both before and after training, surgical residents overwhelmingly agreed with statements that ultrasound would improve their US-based practice, make them a better surgical resident, and improve their practice in resource-limited settings. After a POCUS course designed specifically for surgeons, surgical residents had improved self-efficacy and confidence levels across a broad range of skills.

Left ventricular ejection fraction assessment by non-cardiologists from transverse views using a simplified wall motion score index.

For the non-cardiologist emergency physician and intensivist, performing an accurate estimation of left ventricular ejection fraction (LVEF) is essential for the management of critically ill patients, such as patients presenting with shock, severe respiratory distress or chest pain. Our objective was to develop a semi-quantitative method to improve visual LVEF evaluation. A group of 12 sets of transthoracic echocardiograms with LVEF in the range of 18–64% were interpreted by 17 experienced observers (PRO) and 103 untrained observers or novices (NOV), without previous training in echocardiography. They were asked to assess LVEF by two different methods: i) visual estimation (VIS) by analysing the three classical left ventricle (LV) short-axis views (basal, midventricular and apical short-axis LV section) and ii) semi-quantitative evaluation (base, mid and apex (BMA)) of the same three short-axis views. The results for each of these two methods for both groups (PRO and NOV) were compared with LVEF obtained by radionuclide angiography. The semi-quantitative method (BMA) improved estimation of LVEF by PRO for moderate LV dysfunction (LVEF 30–49%) and normal LVEF. The visual estimate was better for lower LVEF (<30%). In the NOV group, the semi-quantitative method was better than than the visual one in the normal group and in half of the subjects in the moderate LV dysfunction (LVEF 30–49%) group. The visual estimate was better for the lower LVEF (ejection fraction <30%) group. In conclusion, semi-quantitative evaluation of LVEF gives an overall better assessment than VIS for PRO and untrained observers.