Left ventricular function assessed by multigated blood pool single photon emission computed tomography with 99mTc]

To evaluate the usefulness of gated blood pool single photon emission computed tomography with 99mTc (gated SPECT) for assessing left ventricular function, we performed gated SPECT in 2 normal subjects and 18 patients including 13 with ischemic heart disease, 3 with hypertrophic cardiomyopathy and 2 with dilated cardiomyopathy. Left ventricular end-diastolic volume (LVEDV), left ventricular ejection fraction (LVEF) and regional wall motion obtained by gated SPECT were compared with the results of contrast left ventriculography (contrast LVG), echocardiography and planar multigated blood pool imaging (planar blood pool). After the patients' red blood cells were labelled with 30 mCi (1,110 MBq) 99mTc in vivo, gated SPECT was performed in each of 32 projections through a 360 degree arc for each of the cardiac cycle divided into 16. From these images, the left ventricular vertical long-axis image, the horizontal long-axis and short-axis images were reconstructed. To calculate LVEDV, we used serial short-axis images which were composed of the left ventricle. To define left ventricular and left atrial borders, we used amplitude images and cinematic displays of the vertical long-axis image. The level of the optimal cut for delineating the left ventricular border was determined from the volume-cut-level-graph at each background activity, which was constructed by a phantom study. Left ventricular wall motion by gated SPECT was compared with the results of contrast LVG according to segmental analysis. LVEDV obtained by gated SPECT showed an excellent linear correlation with LVEDV calculated by echocardiography (r = 0.98, p < 0.01) and by contrast LVG (r = 0.89, p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)     

Clinical utility of gated cardiac blood pool imaging in congestive left heart failure

Our experience with gated cardiac blood pool imaging in the evaluation of congestive left-sided heart failure was reviewed in 82 patients. Ventricular contraction patterns, right and left ventricular size, and regional wall motion were evaluated from technetium-99m-albumin gated blood pool scans obtained in anterior and left anterior oblique projections. Patterns of ventricular function shown by scan were classified as follows: normal right and left ventricular size and contraction, normal left ventricular size with right ventricular enlargement, left ventricular volume overload, diffuse left ventricular hypokinesis, regional left ventricular asynergy, left ventricular aneurysm and hypertrophic cardiomyopathy. In 34 of 36 patients who underwent cardiac catheterization, the pattern of left ventricular dysfunction revealed by scan agreed with the findings on left ventriculography. Left ventricular end-diastolic diameters were significantly (p < 0.001) increased in patients with heart failure due to previous myocardial infarction, congestive cardiomyopathy, left ventricular volume overload and left ventricular pressure overload. Right ventricular diameters were increased predominantly among patients with congestive cardiomyopathy and mitral stenosis. Clinically, gated cardiac imaging was useful for (1) diagnostic screening prior to cardiac catheterization; (2) determination of the potential for improvement with surgical operation; and (3) prognostication from the severity of left ventricular dysfunction.     

Quantitative radionuclide angiography in the right anterior oblique view: Comparison with contrast ventriculography

Because the right anterior oblique view is widely accepted as the best “single” projection for assessing wall motion, the utility of this view during first pass radionuclide angiography was studied in 44 patients who also underwent contrast ventriculography and coronary arteriography. Of the 44 patients, 8 had a normal heart and 14 had coronary artery disease with normal wall motion on contrast ventriculography. All also had normal contraction on radionuclide angiography. On contrast ventriculography, 22 patients had coronary artery disease and asynergy involving 34 left ventricular segments. Of 17 segments localized to the anterior and apical asynergic areas on contrast ventriculography, 16 were accurately localized with radionuclide angiography. Similarly, of 17 inferior asynergic areas, 13 were also shown to be inferior on radionuclide angiography. In addition, quantitative assessment of the severity of asynergy using the hemiaxis method demonstrated a good correlation between asynergic severity as defined with radionuclide angiography and contrast ventriculography. Of 11 anterior areas, 7 defined as hypokinetic with contrast ventriculography demonstrated chordal shortening of 20.1 ± 5.2 percent (mean ± standard error of the mean) (P < 0.005 compared with normal) on radionuclide angiography. Similarly, four akinetic or dyskinetic segments on contrast ventriculography demonstrated a greater reduction (4.0 ± 4.0 percent) in chordal shortening on radionuclide angiography (P < 0.05 compared with hypokinetic segments). Akinetic apical and inferior segments as defined with contrast ventriculography also showed a marked reduction in wall motion to 10.4 ± 7.3 percent and 7.5 ± 4.1 percent, respectively.After appropriate background subtraction, determination of ejection fraction using radionuclide angiography showed a correlation of 0.839 between the left anterior oblique and right anterior oblique projections independent of the sequence of injection. In addition, ejection fraction determined with radionuclide angiography in the left (r = 0.824) and right (r = 0.801) anterior oblique views correlated well with ejection fraction assessed from contrast ventriculography. Thus, first pass radionuclide angiography performed in the right anterior oblique view is a sensitive noninvasive means of assessing the location and severity of asynergy as well as global left ventricular performance in patients with coronary artery disease.     

Evaluation of cardiac function by radioisotope angiography

Cardiac function can be assessed with noninvasive radionuclide technique. Radioisotope angiography can be performed either using equilibrium acquisition or first pass technique. The most commonly generated measurements are as follows; 1) chamber-to-chamber transit time, 2) cardiac output, 3) left-to-right shunt ratio, 4) left and right ventricular ejection fractions, 5) left ventricular end-diastolic and end-systolic volumes, 6) regional wall motion, 7) peak ejection rate, and 8) peak filling rate. The ejection fraction, the systolic function and the diastolic function are calculated from ventricular volume curves. The left ventricular volume can be determined by two approaches, the geometric method using the left ventricular image to calculate the area and length of the chamber, and the count-based method. Generally, left ventricular wall motion is observed in right anterior oblique(RAO) view for the first pass method and the left anterior oblique(LAO) view for the equilibrium method. On the other hand, three dimensional multigated imaging was superior in allowing evaluation of left ventricular wall motion in all directions and in assessment of the left ventricular function. Three dimensional multigated imaging is very useful for observation of both left ventricular wall motion and left ventricular function in patients with ischemic heart disease, because it is a noninvasive examination. The quantitative gated myocardial SPECT(QGS) was considered to be useful for assessment of left ventricular function and myocardial perfusion.     

Relation of segmental wall motion to global left ventricular function in acute myocardial infarction

The relation of left ventricular regional wall motion to global ventricular function was evaluated by radionuclide ventriculography in 127 patients within 18 hours of acute myocardial infarction. No patient had evidence of previous myocardial infarction. The following parameters were measured: (1) wall motion index; (2) percent of abnormally contracting segment; (3) ejection fraction (EF); (4) end-diastolic volume (EDV) and end-systolic volume (ESV); and (5) peak systolic cuff pressure/end-systolic volume ratio ($\text{PSP}\text{ESV}$). The measurements of global function correlated well with wall motion index (r = 0.83, p < 0.001 for EF; r = ?0.69, p < 0.001 for ESV; and $\text{r}\text{= 0.061,}\text{p}\text{< 0.001}\text{for}\text{PSP}\text{ESV}$), but EDV correlated less well (r = ?0.35, p < 0.001). Multiple linear regression analysis revealed that EF correlated best with wall motion index, and no other parameters of global left ventricular function added significantly to the regression.The correlation of motion in each segment with EF was determined by multiple linear regression analysis. Ejection fraction correlated best with motion in the anterobasal, then in order of correlation, in the apical-septal, inferoapical, anterolateral, and superlateral walls. The relation of EDV, ESV, and degree of percent abnormally contracting segments was as follows: EDV did not increase with a mild regional wall motion abnormality; however, ESV did increase and reduced stroke volume. As percent abnormally contracting segments worsened, enlargement of both EDV and ESV was seen and was associated with further reduction in systolic volume.These data suggest that EF is the best global left ventricular function correlate of the severity of the regional wall motion abnormality, and that abnormal motion in the territory of the left anterior descending coronary best predicts reduction in global left ventricular function. Radionuclide ventriculography is useful in characterizing global and regional left ventricular function in the early hours of acute myocardial infarction.     

Effect of selective coronary arteriography on left ventricular volumes and ejection fraction in man

This study was performed to assess the influence of selective coronary arteriography on left ventricular volumes and ejection fraction in man. In 30 patients with assorted cardiac diseases, left ventricular end-diastolic and end-systolic volumes and ejection fraction were quantitated immediately before and after selective coronary arteriography. In 19 patients (Group A), contrast left ventriculography was performed immediately before and after selective coronary arteriography. In the remaining 11 patients (Group B), multigated equilibrium blood pool imaging was performed just before and after coronary arteriography. In both groups, mean systemic arterial pressure and heart rate did not change from just before the first to immediately before the second assessment of left ventricular volumes and ejection fraction, but left ventricular end-diastolic pressure increased. End-diastolic and end-systolic volume indexes, and ejection fraction did not change from just before to immediately after selective coronary arteriography. Therefore, selective coronary arteriography (1) consistently causes an increase in left ventricular end-diastolic pressure but (2) exerts no effect on left ventricular volumes and ejection fraction, even in patients with severely compromised left ventricular function.     

Effect of oral propranolol on rest and exercise left ventricular ejection fraction, volumes, and segmental wall motion in patients with angina pectoris. Assessment with equilibrium gated blood pool imaging.

The effect of oral propranolol on left ventricular ejection fraction, left ventricular volumes, cardiac output, and segmental wall motion was assessed with multigated blood pool imaging both at rest and during supine exercise in 15 patients with angina pectoris. Propranolol had no effect on resting left ventricular ejection fractions. Before propranolol, they did not change during exercise, whereas after propranolol the ejection fractions increased slightly. Exercise left ventricular ejection fractions increased with propranolol in three patients with resting left ventricular ejection fractions of less than 40 per cent. More specifically, left ventricular end-diastolic volume index, end-systolic volume index, stroke volume index, and cardiac index were not altered significantly at rest or during exercise by propranolol. Exercise left ventricular ejection fractions were increased in five and unchanged in eight patients by propranolol. Those patients with increases in left ventricular ejection fractions had a greater change in left ventricular end-diastolic volume indices and a greater change in left ventricular end-systolic volume indices during exercise while on propranolol. Left ventricular segmental wall motion was not altered significantly during exercise by propranolol. We conclude that: (1) Left ventricular functional responses to propranolol during exercise are heterogeneous and not easily predicted; (2) propranolol causes no consistent deterioration in exercise left ventricular ejection fraction even in patients with resting ventricular ejection fractions less than 40 per cent; (3) increased exercise left ventricular ejection fraction with propranolol is contributed to by significant increases in end-diastolic volume during exercise; and (4) gated blood pool imaging is a useful method for characterising rest and exercise left ventricular ejection fractions and left ventricular volumes during propranolol therapy.     

Phase and amplitude images using Fourier analysis in radioisotopic angiography. Comparison with contrast angiography for studying regional changes in ventricular contraction

Phase-amplitude images and phase distribution histograms, derived from a temporal Fourier analysis of equilibrium ecg-gated blood pool studies, were used to assess the overall wall motion synchronism and to detect regional wall motion abnormalities in 69 consecutive patients with suspected or documented coronary artery disease, in whom biplane contrast left ventriculography and coronary angiography were performed. Four regions were considered on the 15 degrees caudal left-anterior oblique view radionuclide image, in order to identify the 7 conventional angiographic left ventricular wall segments (as the American Heart Association Council of Cardiovascular Surgery). Regional abnormalities on the phase-amplitude images from the 15 degrees caudal left anterior oblique view scans were studied in order to identify local hypokinesis, akinesis or dyskinesis (in accord to definitions used for contrast cineangiography) relative to seven conventional left ventricular wall segments. Results of phase-amplitude image analysis were compared with those of contrast cineangiography. The parametric images showed overall sensitivity of 82% and 92% respectively towards biplane and monoplane (left anterior oblique) contrast cineangiography, with a high degree of specificity (97%). Most akinetic and dyskinetic segments were correctly identified. A significant phase delay (greater than or equal to 70 degrees) from mean value, always occurred in dyskinetic segments and generally related to the severity of the wall motion abnormality. Lower accuracy was observed for hypokinetic regions; sensitivity was lower for apical and antero-lateral segments.(ABSTRACT TRUNCATED AT 250 WORDS)     

Evaluation of segmental left ventricular wall motion by equilibrium gated radionuclide ventriculography

The ability of equilibrium gated radionuclide ventriculography to detect segmental left ventricular (LV) wall motion abnormalities was determined in 26 patients undergoing cardiac catheterization. Multiple gated studies obtained in 30° right anterior oblique and 45° left anterior oblique projections, played back in a movie format, were compared to the corresponding LV ventriculograms. The LV wall in the two projections was divided into eight segments. Each segment was graded as normal, hypokinetic, akinetic, dyskinetic, or indeterminate. Thirteen percent of the segments in the gated images were indeterminate; 24 out of 27 of these were proximal or distal inferior wall segments. There was exact agreement in 86% of the remaining segments. The sensitivity of the radionuclide technique for detecting normal versus any abnormal wall motion was 71%, with a specificity of 99%. Equilibrium gated ventriculography is an excellent noninvasive technique for evaluating segmental LV wall motion. It is least reliable in assessing the proximal inferior wall and interventricular septum.     

Clinical recognition of giant left ventricular aneurysm

The noninvasive diagnosis of left ventricular aneurysm has markedly improved with gated blood pool scintigraphy. However, in patients with giant anterior ventricular aneurysms, the gated blood pool scintigram performed in two standard views (anterior and 40 degree left anterior oblique) may incorrectly suggest ischemic cardiomyopathy. We retrospectively identified five patients who underwent resection of a ventricular aneurysm over a $\text{2}\text{1}\text{2}$ year period and who had preoperative scintigraphic studies that appeared to show severe diffuse left ventricular dysfunction. Contrast ventriculography demonstrated preserved wall motion in septal, inferior and lateral segments not seen by gated blood pool scintigraphy and showed extraordinarily large anterior aneurysms. M-mode or two-dimensional echocardiograms showed intact posterior wall function in all patients, suggesting severe regional myocardial disease rather than global dysfunction. Two-dimensional echocardiography showed additional segments with preserved function as well as discrete aneurysms in all patients. We conclude that gated blood pool scintigraphy, when performed in two standard views, may fail to correctly diagnose some patients with very large anterior wall aneurysms. M-mode echocardiography, two-dimensional echocardiography and additional scintigraphic views that visualize the posterior portions of the left ventricle improve noninvasive diagnosis of patients with resectable giant left ventricular aneurysms.     

Scintigraphic evaluation of left ventricular aneurysm

Gated cardiac blood pool scintigraphy is a noninvasive method to assess regional and global left ventricular function in the patient with suspected true or false left ventricular aneurysm after a myocardial infarction. The procedure is easy to perform and provides reproducible, high resolution images that can accurately distinguish regional from diffuse contractile abnormalities often present after myocardial infarction. An overall accuracy rate of 96 percent for detection of left ventricular aneurysm can be obtained with gated cardiac blood pool scintigraphy as compared with contrast left ventriculography. The procedure also permits assessment of functional reserve of the noninvolved myocardium and thus can provide valuable information on whether enough viable myocardium will remain after aneurysmectomy. The addition of thallium-201 myocardial perfusion scintigraphy may aid in the separation of viable from scarred myocardium at the edge of the aneurysm. Both radionuclide techniques are well suited for screening the patient after infarction with persistent congestive heart failure, malignant arrhythmia or systemic emboli in whom a left ventricular aneurysm may have developed.     

Improved assessment of inferior segmental wall motion by the addition of a 70-degree left anterior oblique view in multiple gated equilibrium scintigraphy

Conventional anterior and 45-degree left anierior oblique (LAO) views are limited in the evaluation of inferior segmental wall motion by multiple gated equilibrium cardiac blood pool scintigraphy. This study evaluated the addition of a 70-degree LAO view by comparing scintigraphic and contrast ventriculography in 25 patients, of whom 17 demonstrated abnormal inferior wall motion. Abnormal inferior wall motion was correctly identified in only 10 of 17 patients in the anterior view, but in 16 of 17 patients in the 70-degree LAO view. The number of assessable inferior segments was improved from 58% in the anterior view to 98% in the 70-degree LAO view. When the inferior segments could be visualized in the anterior view, inferior wall motion was accurately assessed. The addition of the 70-degree LAO view aids in the multiple gated equilibrium scintigraphic detection of inferior wall motion abnormalities with a minor loss in specificity.     

Assessment of myocardial systolic wall thickening using nuclear magnetic resonance imaging

A quantitative nuclear magnetic resonance (NMR) imaging method of evaluating regional left ventricular function was compared with histochemical evidence of infarction in dogs and functional measurements in patients. Short-axis images of the heart were obtained at end-diastole and at 100 ms intervals thereafter. Regional diastolic left ventricular wall thickness and maximal percent systolic wall thickening were measured at the level of the papillary muscles in each of six segments. In six normal dogs, the mean end-diastolic wall thickness was 9 +/- 1.6 mm, and the mean maximal percent thickening was 61 +/- 11%. In eight dogs with a 4 day old infarct, maximal percent thickening was 5 +/- 8% (p less than 0.001) in the infarcted segments. In 10 normal human volunteers, the mean end-diastolic wall thickness was 10.1 +/- 1 mm, and the mean maximal percent systolic wall thickening was 60 +/- 18%. Reduced maximal percent systolic wall thickening was defined as a value greater than or equal to 2 SD below the mean value obtained in normal volunteers. Seven patients with regional wall motion abnormalities were independently assessed by NMR imaging and biplane ventriculography. With a sensitivity of 94% and a specificity of 80%, NMR imaging demonstrated reduced maximal percent systolic wall thickening in the same segments identified as akinetic or dyskinetic by biplane ventriculography. Thus, abnormalities of regional systolic wall thickening are accurately identified with this quantitative imaging technique.     

Pharmacologically induced changes in wall thickening dynamics and mid-ventricular volumes in dogs assessed by prospectively gated computed tomography

Assessment of regional wall thickening dynamics is important for monitoring the response of normal and ischemic myocardium to pharmacologic interventions. Because regional wall thickness can be measured on computed tomographic (CT) scans of the heart, the ability of electrocardiogram-gated computed tomography to determine the effects of pharmacologic agents on global and segmental left ventricular (LV) function was assessed. Eight conditioned dogs were studied at a control state and during drug-induced changes in contractility and loading conditions brought about by the use of isoproterenol (0.15 μg/kg/min), phenylephrine (0.3 μg/kg/min), and verapamil (0.2 mg/kg infused over 10 minutes). Ten contrast-enhanced CT slices (1 cm thick) at the same mid-LV level were reconstructed for each 10% of the R-R interval throughout an average cardiac cycle using prospectively gated CT scans. End-diastolic and end-systolic frames were selected and analyzed for the following: septal, apical, and lateral wall thickness, percent wall thickening, end-diastolic and end-systolic mid-LV volume, and percent change in mid-LV volume.

During control, end-diastolic and end-systolic LV wall thicknesses (in millimeters) were 12 ± 2 and 15 ± 2 for the septal wall, 8 ± 1 and 11 ± 2 for the apical wall, and 10 ± 1 and 12 ± 1 for the lateral wall, respectively. The percent thickening in these respective segments was 24 ± 8, 36 ± 10, and 28 ± 13. The control end-diastolic and end-systolic mid-LV volumes were 16 ± 3 and 12 ± 3 ml, resulting in a percent change of 27 ± 7%. Phenylephrine induced significant thinning of the walls and impairment of systolic thickening, whereas isoproterenol induced opposite effects. Verapamil produced a significant decrease in mean blood pressure (123 ± 9 versus 99 ± 23 mm Hg, p < 0.025), but end-diastolic wall thicknesses were mildly thicker or showed no change and end-systolic wall thicknesses showed no change compared with those in the control state. Similarly, mid-LV volumes and percent change in mid-LV volumes were not different from those during control. Thus, electrocardiogram-gated computed tomography can be used to assess the effects of pharmacologic interventions on global and segmental LV function.     

Echocardiographic analysis of regional left ventricular wall motion in normal children and neonates

Because comprehensive normal data and the effect of observer variability for echocardiographic evaluation of regional left ventricular wall motion are not available in children or newborns, left ventricular wall motion was assessed by measuring regional area change. The study group comprised 55 infants and children with a normal heart: 15 neonates (greater than 1 week to less than 1 month old), 10 infants (greater than 1 month to less than 1 year old) and 30 children, 10 each in the age group greater than 1 year to less than 5 years, greater than 5 to less than or equal to 10 years and greater than 10 years. A combination of parasternal, apical and subcostal two-dimensional echocardiographic views was applied. After planimetry of an end-systolic and end-diastolic frame, the left ventricle was divided into eight equal segments and the percent area change calculated. Both a fixed reference and a floating system correcting for translation and rotation were applied. Intraobserver variability for percent area change measurements was 2.8 +/- 0.9% and 3.8 +/- 1% for observers 1 and 2, respectively. The mean interobserver difference of regional percent area change was 4.7 +/- 1.8%. Normal values for the eight anatomic segments were established in each echocardiographic imaging plane. The overall results were independent of the type of reference system utilized. The subcostal views yielded different results from their parasternal counterparts, probably because of differing imaging planes. These normal values establish a data base in the pediatric age range that can be used to detect abnormal segments in children at risk for developing regional left ventricular wall motion abnormalities.     

Comparison of gated single-photon emission computed tomography with magnetic resonance imaging for evaluation of left ventricular function in ischemic cardiomyopathy

To perform a head-to-head comparison between magnetic resonance imaging (MRI) and gated single-photon emission computed tomography (SPECT) for the evaluation of left ventricular (LV) function (LV ejection fraction [LVEF], LV volumes, and regional wall motion) in patients with ischemic cardiomyopathy, we studied 22 patients with chronic coronary artery disease and LV dysfunction. Multislice, multiphase echoplanar MRI was performed with Philips Gyroscan ACS-NT15. Image analysis was performed using the MASS software package to determine LV end-systolic volume, LV end-diastolic volume, and LVEF. The same parameters were calculated using quantitative gated SPECT software (QGS, Cedars-Sinai Medical Center). The different parameters were compared using linear regression, and correlation coefficients were calculated. Regional wall motion was also determined from both techniques, according to a 13-segment model and a 3-point scoring system (from 1 = normokinesia to 3 = akinesia or dyskinesia). A summed wall motion score was also calculated for MRI and gated SPECT. Good correlations were found between MRI and gated SPECT for all parameters: (1) summed wall motion score^MRI versus summed wall motion score^SPECT: Y = 0.74x + 8.0, R = 0.88, p <0.01; (2) LV end-systolic volume^MRI versus LV end-systolic volume^SPECT: Y = 0.94x − 12.3, R = 0.87, p <0.01; (3) LV end-diastolic volume^MRI versus LV end-diastolic volume^SPECT: Y = 0.93x − 18.4, R = 0.84, p <0.01; and (4) LVEF^MRI versus LVEF^SPECT: Y = 0.97x + 0.68, R = 0.90, p <0.01. For regional wall motion, an exact agreement of 83% was found, with a kappa statistic of 0.77 (95% confidence intervals 0.71 to 0.83, SE 0.03), indicating essentially excellent agreement. Thus, close and significant correlations were observed for assessment of LVEF, LV volumes, and regional wall motion by MRI and gated SPECT in patients with ischemic cardiomyopathy.     

Quantitative assessment of global and regional left ventricular function with low-contrast dose digital subtraction ventriculography

Few studies have compared the use of low-contrast dose digital subtraction ventriculography with conventional ventriculography for quantitative assessment of both global and regional left ventricular function. Accordingly, 34 patients underwent conventional ventriculography using 36 ml of ionic contrast material and digital ventriculography (mask-mode) using 10 ml of contrast diluted in 10 ml of saline and injected over two seconds. Data from two patients were excluded because of ectopy during cineventriculography and from one because of ectopy during both studies. End-diastolic and end-systolic volumes were calculated from both studies by an area-length method and used to calculate ejection fractions. Regional wall motion was quantitated by the centerline method. Results of linear regression analysis demonstrated high correlations for all parameters (end-diastolic volume, r = 0.85; end-systolic volume, r = 0.93; ejection fraction, r = 0.92; quantitative regional wall motion, r = 0.90). Thus, low-contrast dose digital subtraction ventriculography provides an accurate assessment of both global and regional ventricular function and minimizes the required dose and inherent risks of contrast media.     

Method for quantitative analysis of regional left ventricular function with first pass and gated blood pool scintigraphy

The ability of radionuclide angiocardiography to quantitatively assess regional left ventricular function was studied in 33 patients undergoing biplane left ventricular cineangiography (45 ° right anterior oblique projection, and 60 ° left anterior oblique projection with 25 ° caudocranial angulation), and first pass (30 ° right anterior oblique projection) and multiple gated equilibrium (35 ° to 45 ° left anterior oblique projection with 20 ° to 25 ° caudocranial angulation) left ventricular scintigraphy within 48 hours. End-diastolic and end-systolic silhouettes of contrast angiograms were superimposed, and five segments were defined in each plane by radial lines originating from the end-diastolic center of mass. Segmental angiographic ejection fraction (end-diastolic area — end-systolic area/ end-diastolic area) was calculated for each segment by computerized planimetry. Similar segments were defined in the end-diastolic and end-systolic regions of interest of the first pass and gated left ventricular scintigrams, and the segmental scintigraphic ejection fraction (back-ground-corrected end-diastolic counts — background-corrected end-systolic counts/background-corrected end-diastolic counts) was obtained for each.A good correlation was observed between segmentai angiographic and scintigraphic ejection fraction in the segments corresponding to the anterobasal (r = 0.74), anterolateral (r = 0.70), apical (r = 0.77), diaphragmatic (r = 0.71), distal septal (r = 0.66), posterolateral (r = 0.71) and inferolateral (r = 0.60) left ventricular regions. The poor correlation in the posterobasal (r = 0.39), basal septal (r = ?0.02) and superolateral (r = 0.05) segments was probably related to difficulty in defining the aortic valve, overlap of the left atrium and the left ventricle, and inability to visualize the high septum with these scintigraphic techniques. The reproducibility of scintigraphic segmental ejection fraction was studied in 13 patients in whom a second gated scintigram was performed 2 hours after the initial one. Excellent agreement (r = 0.93) was observed for scintigraphic segmental ejection fraction in the distal septal, posterolateral and inferolateral segments. Segmental scintigraphic ejection fraction enables accurate quantitative evaluation of the function of the anterobasal, anterolateral, apical, diaphragmatic, distal septal, posterolateral and inferolateral left ventricular regions with high reproducibility.     

Tomographic gated blood pool radionuclide ventriculography: analysis of wall motion and left ventricular volumes in patients with coronary artery disease

The use of planar radionuclide ventriculography to evaluate global and segmental ventricular function is limited by the superimposition of structures in some projections and the gross segmental resolution of the planar technique. Preliminary reports have suggested the feasibility of tomographic gated radionuclide ventriculography with rotating detector systems. This study tested the hypotheses that 1) tomographic radionuclide ventriculography detects segmental dysfunction at rest not identified with multiview planar studies and single plane contrast ventriculography, and 2) ventricular volumes and ejection fraction calculated from these studies provide data similar to those obtained with angiography and planar radionuclide ventriculography. Gated blood pool tomograms were acquired over 180 degrees at 15 frames per cardiac cycle during the initial 90% of the cardiac cycle. Compared with the multiview planar technique tomographic ventriculography showed an increased sensitivity for detecting left ventricular segments with significant coronary artery stenosis (97 versus 74%, p less than 0.025) without any loss in specificity. Compared with both planar radionuclide and contrast ventriculography, tomographic radionuclide ventriculography also detected more noninfarcted left ventricular segments supplied by stenosed coronary arteries (81 versus 39 and 32%, respectively, p less than 0.01). Tomographic radionuclide ventriculographic measurements of left ventricular volumes and ejection fraction showed close correlations with angiographic and planar radionuclide determinations. Gated blood pool tomography is a sensitive method for the evaluation of segmental wall motion and an accurate method for the measurement of global left ventricular volumes and ejection fraction.