Gated cardiac MRI: ejection-fraction determination using the right anterior oblique view

Fifteen adults underwent gated cardiac MR scans in the right anterior oblique position. End-diastolic and end-systolic images were acquired in an imaging plane parallel to the ventricular septum using spin-echo image acquisition on a 0.35-T system. Analysis of ventricular volumes and ejection fractions was performed using the area-length method. These results were correlated with ejection fractions obtained from angiocardiography. The linear regression line obtained for ejection fraction was y = 0.74x + 16 and the r value was 0.789, indicating a reasonable correlation between the two methods.     

Value of combined assessment of global and segmental ventricular contraction with right anterior oblique ECG-gated first-pass and left anterior oblique equilibrium radionuclide ventriculography

A semi-automated, variable-region-of-interest method of analysis was used to measure both global and segmental left ventricular (LV) and global right ventricular (RV) contraction with ECG-gated first-pass and equilibrium radionuclide ventriculography. Normal values were defined in 20 healthy volunteers, and in 24 symptomatic patients, the results were compared with right anterior oblique (RAO) contrast left ventriculography. The global LV ejection fraction (LVEF) obtained by equilibrium imaging in the left anterior oblique (LAO) projection correlated closely with the results obtained by the gated first-pass method in the RAO projection (r = 0.95) and those obtained with contrast left ventriculography (r = 0.94); furthermore, the interobserver variability was small (r = 0.985). The normal values for LVEF obtained using radionuclide techniques and contrast ventriculography did not differ, but with the equilibrium radionuclide method, the RV ejection fraction (RVEF) values were underestimated in comparison to those obtained by the RAO gated first-pass technique. In five patients with localised inferior segmental akinesis at contrast angiography, the RAO first-pass cine display demonstrated a corresponding wall-motion abnormality in all cases, but LAO equilibrium cine displays did so in only one out of five patients. For segmental quantitation of LV contraction, a computer programme defined the ventricular edge, divided the RAO LV images into five segments and determined both the segmental area contraction (SAC) and the counts-based segmental ejection fraction (SEF). Radionuclide SAC measurements correlated very strongly with SEF measurements (r = 0.94-0.99). Both radionuclide SAC and radionuclide SEF correlated well with contrast angiographic SAC, except in the inferobasal segment.(ABSTRACT TRUNCATED AT 250 WORDS)     

Comparison between vertical parallel hole collimator and 30 degrees rotating slant hole collimator for assessing global and regional left ventricular function by radionuclide angiography

Left ventricular ejection fraction (LVEF) and regional wall motion abnormalities were determined in 40 patients (30 with coronary artery disease and 10 with valvular heart disease) using equilibrium radionuclide angiography. Scintigraphic acquisitions were collected in random order with 2 different collimators as follows: in anterior face (AF), left anterior oblique (25 degrees-45 degrees LAO) and 70 degrees LAO, with a vertical parallel hole collimator (VTC), and in 25 degrees-45 degrees LAO and 65 degrees-80 degrees LAO with a 30 degrees rotating slant hole collimator (RSHC), with the slant of the collimator directed towards the cardiac apex in both projections. Results were compared to contrast ventriculography (CV) performed in the 30 degrees right anterior view (3 segments: anterior, apical, inferior) and in a 60 degrees left anterior oblique view (3 segments: septal, apical and lateral). Radionuclide LVEF in both series was closely correlated with contrast ventriculographic LVEF (r = 0.89, VTC vs CV and r = 0.87, RSHC vs CV, respectively). Regional wall motion analysis was only performed among the 30 patients suffering from coronary heart disease. Eight contrast angiographic studies were normal and 22 abnormal. Global sensitivity and specificity were 100% and 63% with the VTC (3 false positives) and 91% and 87% with the 30 degrees RSHC (2 false negatives and 1 false positive, P = ns). Agreement for the localisation of the regional wall motion abnormalities between CV and radionuclide angiography was 70.6% with the VTC and 71.2% with the RSHC (P = ns).(ABSTRACT TRUNCATED AT 250 WORDS)     

Assessment of left ventricular diastolic function: comparison of contrast ventriculography and equilibrium radionuclide angiography.

Twenty-two patients with coronary artery disease were studied first by radionuclide angiography (RNA) and then by contrast ventriculography. Cardiac medications were discontinued at least 72 hr before study. The patients were studied during atrial pacing at heart rates close to their spontaneous sinus rhythm. Contrast ventriculography was performed at 50 frames/sec in the 30 degrees right anterior oblique projection using 40 ml of a nonionic contrast medium (iopamidol) at a flow rate of 10-12 ml/sec. The contours of the left ventricular silhouette at contrast ventriculography were traced, frame by frame, on a graphic table with a digitizing penlight. Equilibrium 99mTc RNA was performed in the best septal 45 degrees left anterior oblique projection, acquiring 150,000 cts/frame, at 50 frames/sec and with a 5% gate tolerance. Time-activity curves from both end-diastolic and end-systolic ROIs were built and interpolated. Both RNA and contrast ventriculography volume curves were filtered with Fourier five harmonics. A close relationship was found between RNA and contrast ventriculography measurements of peak filling rate normalized to end-diastolic cps (r = 0.87, p less than 0.001) and stroke count (r = 0.87, p less than 0.001), ejection fraction (r = 0.94, p less than 0.001). Thus, in patients with coronary artery disease, LV filling can be accurately assessed using RNA.     

Underestimation of left-ventricular ejection fraction by radionuclide ventriculography in patients with aneurysm

The left-ventricular ejection fraction (LVEF) of 72 patients with aneurysm of the anterior wall was measured by multiple gated blood pool acquisition (MUGA) in the anterior and left anterior oblique (LAO) positions, and by cineangiography (CA) in right anterior oblique (RAO) and LAO projections of 30 degrees and 60 degrees, respectively. The LVEF was overestimated by CA in the LAO projection and by MUGA in the anterior position, but underestimated by CA in the RAO projection (6.1 percentage points) and by MUGA in the LAO position (6.2 percentage points). In 50 patients without aneurysm, no systematical error occurred using MUGA. The underestimation of the LVEF in patients with aneurysm by MUGA in the LAO position is due to differences of photon attenuation in various parts of the cardiac blood pool. This systematical error can be overcome by biplane MUGA.     

Underestimation of left-ventricular ejection fraction by radionuclide ventriculography in patients with aneurysm

The left-ventricular ejection fraction (LVEF) of 72 patients with aneurysm of the anterior wall was measured by multiple gated blood pool acquisition (MUGA) in the anterior and left anterior oblique (LAO) positions, and by cineangiography (CA) in right anterior oblique (RAO) and LAO projections of 30° and 60°, respectively. The LVEF was overestimated by CA in the LAO projection and by MUGA in the anterior position, but underestimated by CA in the RAO projection (6.1 percentage points) and by MUGA in the LAO position (6.2 percentage points). In 50 patients without aneurysm, no systematical error occurred using MUGA. The underestimation of the LVEF in patients with aneurysm by MUGA in the LAO position is due to differences of photon attenuation in various parts of the cardiac blood pool. This systematical error can be overcome by biplane MUGA.Preliminary results were reported at the Symposium of the Working Group on the Use of Isotopes in Cardiology, European Society of Cardiology, Rotterdam, 16th April, 1983     

The last surviving wall

A total of 66 patients with advanced coronary artery disease (CAD) and 36 with dilated cardiomyopathies (DCM) with ejection fractions less than 20% were analyzed retrospectively to establish patterns of wall motion in each of four quadrants on standard left anterior oblique gated radionuclide ventriculograms. In both disease states the best preserved wall motion was found in the basal free wall quadrant of the left ventricle. The two terminal disease states could not be differentiated on the basis of wall motion patterns.     

A comparison of two radionuclide ejection-fraction techniques with contrast angiography in ischemic heart disease and valvular heart disease

First-pass radionuclide angiography (FPRA) in the 30 degree right anterior oblique and equilibrium gated radionuclide angiography (EGNA) in the 45 degree left anterior oblique were used for quantitative measurements of left ventricular ejection fraction (LVEF). Equipment used was a 400T gamma-camera interfaced with a Simis III Informatek computer. The results were compared with contrast angiography (CA). The aim of this study was to determine the sensitivity of both radionuclide techniques. The present data are based on 65 patients in whom CA and EGNA were performed. In 47 patients both FPRA and EGNA were performed. Results suggested that in ischemic heart disease (IHD) and valvular heart disease (VHD) the EGNA technique is well correlated with CA (r = 0.9 and 0.73, respectively). FPRA correlated well only with CA in IHD (r = 0.86), but not in VHD (r = 0.18). This study indicates that both FPRA and EGNA are sensitive, noninvasive techniques for measuring ejection fraction in IHD, while in VHD, EGNA is more sensitive technique than FPRA.     

Nuclear medicine in the diagnosis of cardiac contusion

In 16 patients with blunt trauma to the chest, the role of cardiovascular nuclear medicine was evaluated using anterior chest flow assessment, with first-pass ejection fraction of left and right ventricles and 99mTc-pyrophosphate scintigraphy. The radiopharmaceutical used was pyrophosphate, labelled with approximately 20 mCi 99mTc. The anterior chest flow and first-pass ejection fractions were initially obtained during the injection of 99mTc-pyrophosphate and were followed up 3 h later by anterior, LAO 45 degrees, and left lateral views of the chest, using an LFOV gamma camera with a data processor. The results were compared with serial cardiac enzymes studies, electrocardiograms and echocardiograms. Of the patients, 77% showed scintigraphic evidence of cardiac contusion. The intensity of activity varied from grades I to II; five patients had abnormal echocardiographic findings. Only two had abnormal ejection fractions, and one patient had evidence of left ventricular aneurysm along with poor ventricular performance. Cardiac enzymes were found to be the least helpful. Electrocardiograms, though non-specific for myocardial damage, were abnormal in 62% of the patients. Eleven of our patients had both abnormal ECG and increased PYP uptake. Even though there is no agreement as to which noninvasive parameter is more sensitive in the diagnosis of myocardial contusion, 99mTc-pyrophosphate scintigraphy, in conjunction with ECG, seems promising in this respect.     

Assessment of left ventricular function by ECG-gated myocardial perfusion scintigraphy with image inversion technique: Comparison with equilibrium radionuclide angiography

BACKGROUND: Inversion of gated myocardial perfusion imaging has been proposed for the evaluation of left ventricular function. This study compared the results of inversion technique of gated left anterior oblique 45 degrees images (G-LAO 45 degrees) with those provided by equilibrium radionuclide angiography in the assessment of global left ventricular function in the same patients with suspected or known coronary artery disease. METHODS AND RESULTS: A total of 107 patients (85 men and 22 women, mean age 59 +/- 9 years) with suspected or documented coronary artery disease were studied. Eighty-seven underwent a 2-day stress/rest technetium-99m sestamibi single photon emission computed tomography with acquisition of G-LAO 45 degrees images on the day of rest, and 20 underwent thallium-201 stress/redistribution single photon emission computed tomography with G-LAO 45 degrees image acquisition immediately after redistribution imaging. An excellent correlation (P < .001) with no significant differences was found between left ventricular ejection fraction values provided by inversion G-LAO 45 degree and radionuclide angiography in 87 patients studied with Tc-99m sestamibi and 20 patients studied with TI-201. The Bland-Altman analysis demonstrated the difference in absolute ejection fraction values obtained by inversion G-LAO 45 degree images and radionuclide angiography as <8%. The inversion G-LAO 45 degrees left ventricular ejection fraction distinguishes the patients with myocardial infarction (ejection fraction = 43% +/- 13%) and without myocardial infarction (ejection fraction = 60% +/- 5%) (P < .001). In patients with left ventricular ejection fraction <40%, inversion G-LAO 45 degree images provide evaluation of left ventricular function comparable with that obtained by RNA. CONCLUSIONS: Semiautomated myocardial perfusion gated inversion technique analyzed with a count-based method is useful in the evaluation of left ventricular function and provides similar results to those of radionuclide angiography.     

Assessment of left ventricular function using solid-state gamma camera equipped with a highly-sensitive collimator

PURPOSE: The solid-state gamma camera 2020tc Imager (Digirad, CA) is now commercially available and has been clinically applied. The present study evaluates the feasibility of equilibrium radionuclide ventriculography (ERNV) within a 3 min period using this camera equipped with a highly sensitive collimator. MATERIALS AND METHODS: ERNV was performed from the best septal position (left anterior oblique view) in 20 patients with cardiac disease using a single detector anger-type gamma camera equipped with a low-energy, high-resolution collimator. Immediately thereafter, we performed a second ERNV using the solid-state gamma camera equipped with a highly sensitive collimator. Acquisition periods were 10 and 3 min, respectively. RESULTS: Significantly more counts were collected from over the left ventricle with the solid-state gamma camera over 3 min than those with the anger-type gamma camera over 10 min (817.1 +/- 387.8 k counts vs. 668.2 +/- 327.4 k counts, p < 0.01). The left ventricular ejection fraction obtained from ERNV data using the solid-state gamma camera correlated closely with those acquired by the anger-type gamma camera (r = 0.94, p < 0.0001, SEE = 5.93%). CONCLUSION: The results showed that the solid-state gamma camera could assess left ventricular function with excellent data collection efficiency and high reliability.     

Dual-source-Computertomographie des Herzens

In a newly developed dual-source computed tomography system (DSCT) the relation of heart rate and image quality and the possible advantages of the system’s superior temporal resolution in the evaluation of left ventricular parameters as compared to results of cardiac magnetic resonance imaging (MRI) were assessed. Coronary CT angiography was performed using a DSCT (Somatom Defintion, Siemens Medical Solutions, Forchheim, Germany) in 21 patients (mean age 62±8; 15 male, 6 female). Image quality of the coronary arteries, the heart valves, and the left ventricular myocardium was assessed using a three-point grading scale. Ten of these patients also underwent cardiac MRI for the assessment of left ventricular function, using a SSFP (steady-state free precession) sequence. Left ventricular ejection fractions (LV-EF), the end-systolic volumes (ESV), and the end-diastolic volumes (EDV) were measured employing MRI and DSCT datasets. The image quality ratings for the coronary arteries at the optimal reconstruction interval were diagnostic even in patients with high heart rates (1.42±0.49). Analysis of global LV function using DSCT quantified from CTA datasets showed a good correlation with results of cardiac MRI [EF: r=0.75 (p=0.01); ESV: r=0.72 (p=0.19); EDV: r=0.71 (p=0.02)]. The dual-source CT system offers robust image quality of the coronary arteries, independent of the heart rate, and provides combined diagnostic imaging of coronary arteries, the heart valves, the myocardium, and the global left ventricular function.     

Noninvasive evaluation of the left and right ventricular function using magnetic resonance

MR imaging is one of the methods allowing the measurement of heart volumes. It provides oblique body sections along the cardiac axes according to cardiac anatomical planes and a spontaneous contrast between blood and myocardium. This study was aimed at evaluating the reliability of both ventricular volumes and ejection fraction measurement by applying the area-length method in patients with a normal left ventricle (group A, 13 patients), in patients with a dilated hypokinetic left ventricle (group B, 20 patients), in cases with segmental abnormalities of the kinesis of the left ventricle following myocardial infarction (group C, 15 patients) and in cases with pathologic involvement of the right ventricle alone for the calculation of the right ventricular ejection fraction (group D, 16 patients), as compared with ventriculography. Good correlations between MR ejection fraction and angiographic ejection fraction were observed in all groups (group A: r = 0.79, p less than 0.001; group B: r = 0.80, p less than 0.001; group C: r = 0.97, p less than 0.001; group D: r = 0.98, p less than 0.001). In the patients in groups A and D volumetric values were constantly underestimated, both telediastolic and telesystolic, due to both the partial volume effect and the cardiac rotation and translation during systole. MR imaging emerges as a reliable method which can easily be applied to the evaluation of left and right ventricular function even in routine examinations.     

Exercise radionuclide ejection fraction: correlation with exercise contrast ventriculography.

Thirty-one patients with known or suspected coronary artery disease or aortic valvular disease were studied at rest and during supine bicycle exercise with radionuclide and contrast left ventriculography. The radionuclide ejection fractions calculated independently by three observers correlated well at rest (r = 0.96) and with exercise (r = 0.94). The calculated values also correlated well with those obtained for contrast ventriculography using the area-length method Dodge (r = 0.89 at rest and r = 0.90 with exercise). The results suggest that further clinical applications of exercise radionuclide ventriculography are justified.     

Nuclear medicine in the diagnosis of cardiac contusion

In 16 patients with blunt trauma to the chest, the role of cardiovascular nuclear medicine was evaluated using anterior chest flow assessment, with first-pass ejection fraction of left and right ventricles and ^99mTc-pyrophosphate scintigraphy. The radiopharmaceutical used was pyrophosphate, labelled with approximately 20 mCi^99mTc. The anterior chest flow and first-pass ejection fractions were initially obtained during the injection of ^99mTc-pyrophosphate and were followed up 3 h later by anterior, LAO 45°, and left lateral views of the chest, using an LFOV gamma camera with a data processor. The results were compared with serial cardiac enzymes studies, electrocardiograms and echocardiograms. Of the patients, 77% showed scintigraphic evidence of cardiac contusion. The intensity of activity varied from grades I to II; five patients had abnormal echocardiographic findings. Only two had abnormal ejection fractions, and one patient had evidence of left ventricular aneurysm along with poor ventricular performance. Cardiac enzymes were found to be the least helpful. Electrocardiograms, though non-specific for myocardial damage, were abnormal in 62% of the patients. Eleven of our patients had both abnormal ECG and increased PYP uptake. Even though there is no agreement as to which noninvasive parameter is more sensitive in the diagnosis of myocardial contusion, ^99mTc-pyrophosphate scintigraphy, in conjunction with ECG, seems promising in this respect.     

Dual-source cardiac CT imaging with improved temporal resolution: Impact on image quality and analysis of left ventricular function

In a newly developed dual-source computed tomography system (DSCT) the relation of heart rate and image quality and the possible advantages of the system's superior temporal resolution in the evaluation of left ventricular parameters as compared to results of cardiac magnetic resonance imaging (MRI) were assessed. Coronary CT angiography was performed using a DSCT (Somatom Defintion, Siemens Medical Solutions, Forchheim, Germany) in 21 patients (mean age 62+/-8; 15 male, 6 female). Image quality of the coronary arteries, the heart valves, and the left ventricular myocardium was assessed using a three-point grading scale. Ten of these patients also underwent cardiac MRI for the assessment of left ventricular function, using a SSFP (steady-state free precession) sequence. Left ventricular ejection fractions (LV-EF), the end-systolic volumes (ESV), and the end-diastolic volumes (EDV) were measured employing MRI and DSCT datasets. The image quality ratings for the coronary arteries at the optimal reconstruction interval were diagnostic even in patients with high heart rates (1.42+/-0.49). Analysis of global LV function using DSCT quantified from CTA datasets showed a good correlation with results of cardiac MRI [EF: r=0.75 (p=0.01); ESV: r=0.72 (p=0.19); EDV: r=0.71 (p=0.02)]. The dual-source CT system offers robust image quality of the coronary arteries, independent of the heart rate, and provides combined diagnostic imaging of coronary arteries, the heart valves, the myocardium, and the global left ventricular function.     

Videodensitometric ejection fractions from intravenous digital subtraction left ventriculograms: correlation with conventional direct contrast and radionuclide ventriculography

Forty-three patients who had undergone direct-contrast ventriculography were submitted to intravenous digital subtraction ventriculography and first-pass radionuclide ventriculography to compare the left ventricular ejection fractions obtained by each method. Ejection fractions were calculated by the area-length method from the direct contrast ventriculograms, by both area-length and videodensitometric methods from the digital subtraction ventriculograms, and by count densitometry from the radionuclide ventriculograms. Satisfactory correlations were found between values obtained by the late mask resubtracted videodensitometric method and the radionuclide method (r = 0.85) and by the digital ventriculographic area length method and direct-contrast method (r = 0.88). Videodensitometric methods may be an alternative way to estimate left ventricular ejection fractions accurately without reliance on geometric assumptions about the shape of the left ventricular cavity.     

Correlation of right and left ventricular ejection fraction and volume measurements

First-pass radiocardiography and biplane angiocardiography were performed on 13 patients with left-sided regurgitant valvular disease (R+) and 7 patients without regurgitation but with coronary artery disease and/or cardiomyopathy (R-). Right and left ventricular volumes and ejection fractions were calculated and compared. In the R- group, corresponding right and left ventricular volumes and ejection fractions correlated highly with each other (r = 0.86-0.89, p approximately equal to 0.01). Ejection fractions in the R+ group correlated (r = 0.64, p less than 0.05) only because stroke volume correlation was very high (r = 0.93), with end-diastolic and end-systolic volumes showing no significant correlation. Right ventricular ejection fraction (RVEF) decreased significantly with increasing mean pulmonary artery pressure (PAP) in both R- and R+ groups. The correlation of RVEF and LVEF in the R- group appears to be multifactorial in origin, consisting of effects of increased PAP, the mechanical interference of an enlarged left ventricle on the right ventricle, and direct biventricular ischemic effects. In the R+ group, the correlation appears to be due to only increased PAP and its sequelae.     

Assessment of global left ventricular function: comparison of cardiac multidetector-row computed tomography with angiocardiography

OBJECTIVE: Evaluation of left ventricular function using electrocardiogram (ECG)-gated multidetector row CT (MDCT) by using 3 different volumetric assessment methods in comparison to assessment of the left ventricular function by invasive ventriculography. METHODS: Thirty patients with suspected or known coronary artery disease underwent MDCT coronary angiography with retrospective ECG cardiac gating. Raw data were reconstructed at the end-diastolic and end-systolic periods of the heart cycle. To calculate the volumes of the left ventricle, 3 methods were applied: The 3-dimensional data set (3D), the geometric hemisphere cylinder (HC), and the geometric biplane ellipsoid (BE) methods. End-diastolic volumes (EDV), end-systolic volumes (ESV), the stroke volumes (SV), and ejection fractions (EF) were calculated. The left ventricular volumetric data from the 3 methods were compared with measurements from left ventriculography (LVG). RESULTS: The best results were obtained using the 3D method; EDV (r = 0.73), ESV (r = 0.88), and EF (r = 0.76) correlated well with the LVG data. The EDV volumes did not differ significantly between LVG and the 3D method (P = 0.24); however, ESV, SV, and EF differed significantly. The ESV were significantly overestimated (P < 0.01), leading to an underestimation of the SV (P < 0.01) and the EF (P < 0.01). The HC method resulted in the greatest overestimation of the volumes. The EDV and the ESV were 31.8 +/- 37.6% and 136.4 +/- 92.9% higher than the EDV and ESV volumes obtained by LVG. Bland-Altman analysis showed systematic overestimation of the ESV using the HC method. CONCLUSION: MDCT with retrospective cardiac ECG gating allows the calculation of left ventricular volumes to estimate systolic function. The 3D method had the highest correlation with LVG. However, the overestimation of the ESV is significant, which led to an underestimation of the SV and the EF.     

Radiocardiographic evaluation of left ventricular function after inhalation of C15O2

Inhalation of C15O2 delivers a bolus of labelled water into the pulmonary veins and the left atrium; analysis of the left ventricular curve provides an easy method for the evaluation of left ventricular function. the patient was seated before six collimated probes positioned toward the lungs. An additional probe was directed toward the heart in a modified 15 to 20 degrees left anterior oblique projection. One to two mCi C15O2 was administered per study. The left ventricular curve was analysed and the ejection fraction was calculated using a new method. The background was first calculated for the cycle with the largest diastolic counts using characteristic points of the curve before and after transit of the indicator through the left ventricle. For the other cycles, the background was considered to be a constant fraction of the end-diastolic counts. The left ventricular ejection fraction was obtained for each cycle after corresponding background subtraction as the ratio of diastolic activity minus systolic activity over diastolic activity. The ejection fraction thus determined in 20 patients was highly reproducible from beat to beat and from study to study in the same patient (r = 0.97 and 0.96). It corresponded closely to the ejection fraction determined using a camera-computer system (r = 0.92). We conclude that C15O2 inhalation is an easy, rapid, reproducible and attractive method to assess left ventricular function.