Objective and subjective analysis of left ventricular angiograms

3-D phantom and in vivo cardiac speckle tracking using a matrix array and raw echo data

Cardiac motion has been tracked using various methods, which vary in their invasiveness and dimensionality. One such noninvasive modality for cardiac motion tracking is ultrasound. Three-dimensional ultrasound motion tracking has been demonstrated using detected data at low volume rates. However, the effects of volume rate, kernel size, and data type (raw and detected) have not been sufficiently explored. First comparisons are made within the stated variables for 3-D speckle tracking. Volumetric data were obtained in a raw, baseband format using a matrix array attached to a high parallel receive beam count scanner. The scanner was used to acquire phantom and human in vivo cardiac volumetric data at 1000-Hz volume rates. Motion was tracked using phase-sensitive normalized cross-correlation. Subsample estimation in the lateral and elevational dimensions used the grid-slopes algorithm. The effects of frame rate, kernel size, and data type on 3-D tracking are shown. In general, the results show improvement of motion estimates at volume rates up to 200 Hz, above which they become stable. However, peak and pixel hopping continue to decrease at volume rates higher than 200 Hz. The tracking method and data show, qualitatively, good temporal and spatial stability (for independent kernels) at high volume rates.

The use of periinfarct contrast-enhanced cardiac magnetic resonance imaging for the prediction of late postmyocardial infarction ventricular dysfunction

BACKGROUND

Although ejection fraction (EF) both perimyocardial infarction (MI) and late post-MI are important prognostic factors, only implantable cardioverter-defibrillator trials of post-MI patients with depressed late EF have shown improved survival. This may relate to imprecision of early EF because of post-MI stunning. We sought to determine if peri-MI infarct size, as measured by cardiac magnetic resonance (CMR), is superior to early EF to predict late post-MI EF.

METHODS

Seventy-three patients with ST-elevation MI had infarct size and EF quantified using CMR early (<1 week) and late (>3 months) post-MI.

RESULTS

Late EF was significantly correlated with early EF (R = 0.734, P < .001), and with infarct size (R = -0.661, P < .001), and both early EF and infarct size were significant predictors of late EF. Subgroup analyses showed that low late EF (<or=35%) was better predicted by infarct size than early EF. Half of the patients with early EF <or=35% had a late EF >35%. There was no difference in early EF between the subgroup with a late EF >35% compared to the subgroup with late EF </=35% (29.7% +/- 4.6% vs 28.0% +/- 4.9%, P = .414). There was, however, a significant difference between these 2 groups in infarct size (22.6% +/- 10.8% vs 34.7% +/- 7.8%, P = .011).

CONCLUSIONS

Infarct size as determined by CMR immediately post-MI is a significant predictor of late EF and is superior to early EF in patients with initially depressed EF. Further studies are warranted to assess whether infarct size estimation by CMR after acute MI can better identify patients who are at risk for sudden cardiac death than early EF.

A knowledge-based boundary delineation system for contrast ventriculograms

Automated left-ventricle (LV) boundary delineation from contrast ventriculograms has been studied for decades. Unfortunately, no accurate methods have ever been reported. A new knowledge based multistage method to automatically delineate the LV boundary at end diastole (ED) and end systole (ES) is discussed in this paper. It has a mean absolute boundary error or about 2 mm and an associated ejection fraction error of about 6%. The method makes extensive use of knowledge about LV shape and movement. The processing includes a multiimage pixel region classification, shape regression, and rejection classification. The method was trained and cross-validated tested on a database of 375 studies whose ED and ES boundary had been manually traced as the ground truth. The cross-validated results presented in this paper show that the accuracy is close to and slightly above the interobserver variability.

Accuracy of quantitative ventriculographic analysis at reduced frame rates

OBJECTIVE

We measured the error in left ventricular (LV) volume and wall motion measurement from recording contrast ventriculograms at 15 frames/sec instead of 30 frames/sec.

BACKGROUND

Angiograms are increasingly recorded at 15 frames/sec instead of 30 frames/sec to improve efficiency. However the resulting error in quantitative analysis has not been evaluated.

METHODS

Contrast ventriculograms recorded at 30 frames/sec of 23 patients undergoing diagnostic studies were digitized from cine film. End diastolic volume (EDV), end systolic volume (ESV), ejection fraction, anterior wall motion, and inferior wall motion were measured from a full set recorded at 30 frames/sec and from two reduced data sets at 15 frames/sec generated from the even and odd numbered frames. Intraobserver variability was compared with the error due to frame rate reduction.

RESULTS

The error due to frame rate reduction did not differ significantly from intraobserver variability (p > 0.1 for all), measuring 2.6 +/- 2.2 ml (r = 0.997) vs. 1.9 +/- 1.2 ml (r = 0.999), respectively for EDV, 2.4 +/- 1.8 ml (r = 0.991) vs. 2.1 +/- 1.7 ml (r = 0.994), respectively for ESV, and 0.2 +/- 0.2 percent (r = 0. 981) vs. 0.1 +/- 1.2 percent (r = 0.994), respectively for ejection fraction. The error and variability for wall motion were 0.3 +/- 0.3 SD (r = 0.928) vs. 0.2 +/- 0.1 SD (r = 0.946), respectively for the anterior wall and 0.2 +/- 0.2 SD (r = 0.963) vs. 0.2 +/- 0.1 SD (r = 0.968), respectively for the inferior wall.

CONCLUSION

Imaging the LV at 15 frames/sec does not cause a significant error in measuring LV volume and function compared with imaging at 30 frames/sec. Cathet. Cardiovasc, Intervent. 48:18-21, 1999.

Normal left ventricular volumes and ejection fraction: assessment with quantitative digital cardioangiography

The aim of this study was to assess the accuracy and precision of a digital angiography system, the General Electric DX system, as compared to conventional left ventricular cineangiography. After a phantom study, sixty patients with normal coronary arteries and normal left ventricles (LV) were studied. The LV contours were manually traced from raw or subtracted digital runs and from the cine films in an independent manner. A regression formula was used to adjust the DX derived data to the cine film results (Vcorrected = 0.693 Vmeasured +8.65 ml). There was an excellent correlation between the two methods in the end-diastolic volume index (r = 0.97, sd = 4.2 ml/m2), the end-systolic volume index (r = 0.95, sd = 2.7 ml/m2), the stroke volume index (r = 0.93, sd = 4.1 ml/m2), and the ejection fraction (r = 0.85, sd = 3.45%). We conclude that manual tracing of LV contours from either raw or subtracted digital images provides reliable and accurate measurement of LV volume and ejection fraction.

Determination of ventricular ejection fraction: a comparison of available imaging methods. The Cardiovascular Imaging Working Group

Knowledge of left ventricular ejection fraction has been shown to provide diagnostic and prognostic information in patients with known or suspected heart disease. In clinical practice, the ejection fraction can be determined by using one of the five currently available imaging techniques: contrast angiography, echocardiography, radionuclide techniques of blood pool and first pass imaging, electron beam computed tomography, and magnetic resonance imaging. In this review, we discuss the clinical application as well as the advantages and disadvantages of each of these methods as it relates to determination of ventricular ejection fraction.

On-line evaluation of systolic performance by densitometry in digital left ventriculography

The angiocardiographic evaluation of left ventricular end-diastolic (LVEDV) and end-systolic (LVESV) volumes and ejection fraction (EF) is routinely performed by the area-length method (ALM) but may lead to erroneous results. Digital imaging in real time allows densitometric procedures of determining left ventricular (LV) performance to be applied alternatively. In this study, we present densitometric algorithms for the analysis of LVEDV, LVESV, and EF from digital image data, establish accuracy and reproducibility, and determine value and limitations in comparison with ALM in single-plane 30 degrees right anterior oblique (RAO) projection. A linear relationship between iodine depth and measured densities is mainly burdened with scatter radiation and beam hardening which reduce primary radiation and suppress iodine depth. However, facilities such as deconvolution and correction algorithms are capable of reducing these sources of error. In the present study, computer-analyzed contrast images of iodine-filled wedges and spheres showed a near-linear relationship between iodine depth between 50-100 mg/cm2 and measured densities. Contrast images of heart casts and LV angio-grams of 54 patients were obtained with a digital image acquisition and processing system, and evaluated by two independent observers. The phantom study resulted in significantly (p < or = 0.01) better densitometric standard errors of estimate for volumes [3.3 ml densitometry (DENS) vs. 8.9 ml (ALM)] and simulated EF [4.3% (DENS) vs. 7.8% (ALM)] than ALM. The standard error of estimate for the comparison between both methods was 8.4 ml for volumes and 7.5% for EF. Densitometric volumes tended to underestimate volumes calculated by ALM. The angiographic study of patients demonstrated significant correlations between both methods (LVEDV r = 0.78, LVESV r = 0.83, total volumes: r = 0.89; EF r = 0.88). The standard errors of estimate can be ascribed to systematic, method-related errors of both DENS and ALM (LVEDV +/- 28.9 ml, LVESV +/- 23.4 ml, total volumes (EDV and ESV) +/- 27.1 ml; EF +/- 8.1%). The intra- and interobserver variability, respectively, exhibited significantly smaller (p < or = 0.01 and p < or = 0.05, respectively) standard errors of estimate for densitometric EF [4.6% (DENS) vs. 8.5% (ALM) and 7.1% (DENS) vs. 10.3% (ALM), respectively]. Inclined but not significant differences were found for LVEDV and LVESV. In conclusion, the data presented indicate that the calculation of LV volumes and EF in digital left ventriculography may be performed accurately by densitometric calculation in single-plane 30 degrees RAO projection. Minor underestimations in densitometric volume determination may be anticipated in the evaluation of LV geometry.

Improved detection of abnormal left ventricular wall motion using tomographic radionuclide ventriculography compared with planar radionuclide and single plane contrast ventriculography

Tomographic radionuclide ventriculography is a technique which could have major advantages over conventional planar imaging, such as better assessment of ventricular wall motion abnormalities. This possibility was therefore investigated in 100 consecutive patients undergoing routine cardiac catheterization. Following angiography, planar blood pool images were conventionally acquired and tomographic imaging performed using the Aberdeen Section Scanner. All derived wall motion data were subsequently analysed in an objective and blinded manner. The mean age was 56 (range 33-71) and 79% were male. 67 patients had experienced prior myocardial infarction, 27 were categorized as having significant and six insignificant coronary artery disease. The detection rates for patients with prior myocardial infarction were 95% for angiography, 57% for planar imaging and 90% for tomography. Even taking patients with only prior anterior myocardial infarction, the detection rates were 94%, 63% and 91% respectively. For those residual patients with significant coronary artery disease, the rates were 7%, 0% and 59% respectively. Overall for the detection of patients with significant coronary artery disease, the sensitivity was 70%, 40% and 81% respectively. Patients with insignificant coronary artery disease did not demonstrate any abnormalities using any method. These results demonstrate that tomography and angiography have similar detection rates in the presence of significant coronary artery disease and both are superior to planar imaging.

Densitometric assessment of regional left ventricular systolic function during graded ischemia in the dog by use of dual-energy digital subtraction ventriculography

Densitometric analysis of images obtained by digital subtraction angiography (DSA) allows for more reproducible and less operator-dependent quantitation of ventricular function. Conventional DSA uses temporal subtraction but is limited by misregistration artifacts. Dual-energy digital subtraction angiography (DE-DSA) is immune to such misregistration artifacts. The ability of DE-DSA to quantitate changes in regional ventricular volume resulting from ischemia was tested. Densitometric analysis of both phase-matched and ejection fraction DE-DSA images was used to quantitate regional left ventricular systolic function during four levels of ischemia ranging from mild to severe in open-chest dogs (n = 10). DE-DSA left ventriculograms were obtained by means of central venous injections of iodinated contrast medium. Ischemia was graded according to percentage of systolic wall thickening as measured by sonomicrometry. Phase-matched end-systolic images were obtained at each of four levels of ischemia by subtracting an end-systolic control image from each end-systolic ischemic image. Ejection fraction images were obtained at the control level and at each level of ischemia by subtracting an end-systolic image from an end-diastolic image of the same cardiac cycle. The resulting wall motion difference signals represent the changes in regional ventricular volumes and were quantitated by densitometry. Densitometry was able to detect the effect of all levels of ischemia on regional function, even the mildest. Densitometric analysis of both phase-matched and ejection fraction DE-DSA images provides a sensitive technique for detecting and quantitating the changes in regional left ventricular systolic volume that occur with ischemia.

Reverse redistribution on Tl-201 SPECT images after reperfusion therapy for acute myocardial infarction: possible mechanism and prognostic implications

So-called reverse redistribution on stress Tl-201 imaging has been reported previously, but its significance and clinical implications are not well understood. In patients who received reperfusion therapy for acute myocardial infarction, we frequently observed reverse redistribution on stress Tl-201 images. To investigate the significance of reverse redistribution, 61 patients who underwent reperfusion within 4 h of the onset of chest pain underwent submaximal exercise Tl-201 imaging 3 weeks later. We performed simultaneous coronary arteriography and left ventriculography. We divided these 61 patients into three groups based on the pattern of Tl-201 images. Reverse redistribution was found in 19 patients (Group A), 12 patients had redistribution (Group B), and 30 patients had nonreversible defects (Group C). All patients in Group A had less residual stenosis than those in the other groups, and showed significant improvement of left ventricular function. Furthermore, 12 patients (Group A) demonstrated reverse redistribution or a normal pattern in a follow-up study performed 12 months later. However, in the delayed images the defect was smaller than that shown in the previous study. None of the patients had any symptoms and all returned to their previous occupations. In conclusion, reverse redistribution was common in patients undergoing reperfusion therapy for acute myocardial infarction, especially those with little residual stenosis. Reverse redistribution appears to indicate improved regional wall function in such patients.

Interstudy reproducibility of biplane cine nuclear magnetic resonance measurements of left ventricular function

Cine nuclear magnetic resonance (NMR) imaging, as a noninvasive and high-resolution imaging modality, has been shown to be reliable for determining absolute left ventricular (LV) volumes and ejection fraction. A relatively new gradient echo cine NMR approach using 2 orthogonal long-axis planes (2- and 4-chamber) aligned with the true axes of the left ventricle has been previously developed and validated against radiographic biplane LV cineangiography. The aim of the present investigation was to determine the reproducibility of this more rapid cine NMR approach for the measurement of LV volumes and ejection fraction. Eighteen normal subjects underwent 2 cine NMR studies, on different days, using a 1.5-tesla clinical imaging system. Studies were analyzed on-line and blindly by 2 independent observers. Intraobserver error was also determined in a blinded manner. Mean values of measurements determined by this method in this group of normal subjects were end-diastolic volume (120 +/- 20 ml), end-systolic volume (39 +/- 9 ml) and ejection fraction (67 +/- 4%). Paired analysis of data revealed no significant bias between interstudy, interobserver or intraobserver measurements, except for interobserver end-diastolic volume, where the first observer measurements were slightly elevated (5.6 +/- 7.8 ml) compared with the second. This resulted in a small difference in ejection fraction (1.7 +/- 2.3%) between observers. The absolute variation between measurements (square root of variance components) was low for all interstudy, interobserver and intraobserver comparisons: end-diastolic volume was less than +/- 6.7 ml, end-systolic volume less than +/- 3.5 ml and ejection fraction less than +/- 2.4%.(ABSTRACT TRUNCATED AT 250 WORDS)

Usefulness of digital angiography in the assessment of left ventricular ejection fraction

With modern digital cardiac systems the image data are digitized on-line and in real-time, allowing the replay and subsequent interpretation and analysis during or directly after the cardiac catheterization procedure. In this study we have evaluated the advantages and limitations of a manual tracing technique for left ventricular digital angiograms on the Phillips DCI system. Thirty-three patients who were catheterized for suspected coronary artery disease were studied. The manual tracings were performed by a senior cardiologist and an experienced function-analyst. It was found that the short- and long-term intraobserver variabilities in the assessment of the global ejection fraction were very small; short-term mean difference +/- standard deviation (correlation coefficient): 0.5 +/- 2.7 (r = 0.97) global EF%-units; long term; 0.7 +/- 2.7 (r = 0.96) EF%-units. The interobserver variabilities (5.1 +/- 4.8 (r = 0.93) EF%-units) were slightly higher than the intraobserver variabilities. A decrease by 25% in the amount of contrast medium administered did not significantly influence the variabilities in the contour tracings, which would suggest the use of smaller doses. At the average, the cardiologist and the function-analyst required 6 and 11 min of analysis time for a left ventricular study, respectively, emphasizing the need for further developments towards automated contour detection. Finally, an excellent correlation was found with a standard off-line cinefilm analysis procedure. Thus, it may be concluded that quantitative digital left ventricular angiography based on manual tracing of the outlines performed immediately following the cardiac catheterization (post-processing) is feasible as a routine procedure for the assessment of left ventricular function.

Quantitative echocardiographic analysis of global and regional left ventricular function: a problem revisited

We recorded two-dimensional echocardiograms simultaneously with the respiration measurements of 20 normal subjects and 20 patients with anterior myocardial infarction. The apical long-axis and four-chamber views were quantitatively analyzed. Measurement variability of global ejection fraction and regional ejection fraction of 100 regions was calculated during inspiration and at end-expiration for two observers. To minimize variability, the endocardial contour was redefined and traced with an improved computer-assisted tracing system. Variability (absolute mean difference) between two beats at end-expiration was significantly less than during inspiration (p less than 0.05): for ejection fraction the variability at end-expiration was 3.4% and the variability during inspiration was 6.4% (mean, 54%; SD, 7%); for regional ejection fraction the variability at end-expiration was 11.8% and the variability during inspiration was 21.5% (mean, 56%; SD, 15%). Intraobserver and interobserver variability values of one beat at end-expiration for ejection fraction were 3.1% and 3.8%, respectively, and 9.5% and 12.8%, respectively, for regional ejection fraction. Variability in patients with myocardial infarction was comparable. This method of recording respiration and analyzing left ventricular function at end-expiration, with a new contour definition and tracing system, provides a measurement variability that is considerably less than that reported in previous echocardiographic studies and that is comparable to angiographic methods.

Detection and quantitation of ischemic left ventricular dysfunction using a new video intensity technique for regional wall motion evaluation

Eighty patients with ischemic heart disease and 17 normal subjects were evaluated for left ventricular regional wall motion by means of a new method. The wall motion analysis is based on video intensity. This technique uses a temporally sliding analysis to evaluate the cardiac cycle in 100 msec intervals. Presence of coronary artery disease was defined as more than 50% measured diameter stenosis. Wall motion abnormalities in regions perfused by stenotic vessels were most common in early diastole (76%). Sensitivity of this method at rest in patients with coronary artery disease was 79.7% (p less than 0.0001) and overall accuracy was 84.2% (p less than 0.0001). Abnormalities in both systole and diastole were more common in regions perfused by severe lesions (greater than 75%) than in those perfused by moderately stenotic (less than 75%) vessels (p less than 0.05). A comparison of the new method with phase and amplitude analysis was performed in 15 patients and with two-frame analysis in 40 patients. This new method yielded a higher sensitivity than either of the other two methods.

An off-line digital system for reproducible interpretation of the exercise ECG

Exercise electrocardiograms of 20 patients were analyzed using a customized software exercise electrocardiographic program and compared to measurements made by two cardiologists performing independent interpretations. The computerized program requires identification of the PQ junction, J point, and tracing of the ST-segment in three consecutive beats. The proportion of variance for J point, and ST 80 measurements was 0.93 and 0.90, respectively, when the same electrocardiogram was processed twice and analyzed by two separate cardiologists. The same 20 exercise electrocardiograms were analyzed by two other experienced cardiologists without computerized measurements. The proportion of variance was less at 0.73 and 0.76 for the J point and ST 80 measurements, respectively. The average amount of time required for the cardiologist to over read the computerized measurements was 2.7 +/- 1.5 minutes per ECG as compared to 20.7 +/- 11 minutes for the cardiologists who did not have computer-assisted measurements (p less than 0.0001). Thus, off-line computerized exercise electrocardiographic interpretation is highly reproducible, accurate, time-sparing for cardiologist over read function, and suitable for use in large-scale clinical trials.

Accuracy of subjective and computer-assisted assessments of angiographic left ventricular regional wall motion

To evaluate the accuracy of angiographic methods for analysis of left ventricular regional wall motion, we measured the ability of a carefully performed subjective analysis (three independent observers) and that of three computer-assisted methods (centerline, radial, and area) to detect the presence of significant coronary artery disease. Normal ranges were established in 90 studies showing normal wall motion, and accuracy was tested in a second, consecutive series of 43 ventriculograms. The results show that the subjective method best separated those regions with from those without significant coronary disease. The subjective method also demonstrated sensitivity comparable to the centerline and radial methods. Among the computer-assisted methods, the area method was least sensitive but most specific for both anterior and inferior region coronary disease. The centerline and radial methods were highly sensitive, but less specific. When coronary disease was defined by electrocardiographic Q-waves, the area method had superior accuracy. Further analysis showed the following: 1) For the centerline and radial methods, long-axis reregistration of the end-systolic frame resulted in loss of sensitivity but increased specificity for anterior wall coronary disease, and little change in analysis of the inferior wall; 2) inclusion or exclusion of the apex had little effect on predictive accuracy for anterior wall coronary disease; 3) as expected, sensitivity and specificity results of all methods were dependent on the selection of a normal range cutoff value; but when performance was optimized, the subjective and area methods had a higher overall predictive accuracy than the centerline method; 4) It is likely that all three computer-assisted methods could be calibrated to give indications of degrees of hypokinesis, as their results correlated well with subjective observers' evaluations over the entire range of scores. These results should assist in selection of the optimal method for regional wall motion analysis in clinical and research applications. As currently applied, the area method is the most specific of the computer-assisted methods tested; the centerline and radial methods have highest sensitivity and therefore are most suited to detection of mild degrees of hypokinesis.

Ischemic heart disease and regional left ventricular wall motion: a study comparing radial, centerline and a video intensity based slope technique

Left ventricular regional wall motion in ischemic heart disease was evaluated and compared using three different methods based on radiographic ventriculograms. Radial method uses an internal reference system, and centerline method employs an external reference system, both methods are based on two frame analysis. The last method, an automated video intensity technique, analyzes on a frame by frame basis utilizing an external reference system. A total of 42 patients were included in the study, of these 12 had a history of myocardial infarction. Significant coronary artery stenosis was defined as 50% measured diameter reduction. Right coronary artery (29/42) was most commonly involved. Single vessel disease was present in 18 patients, two vessel disease in 15 and three vessel disease in eight patients. The radial method detected abnormal wall motion in 16/42 patients, centerline method yielded a detection accuracy of 22/42 and with the new technique, asynchrony was noted in 39/42 patients. All three methods detected regional wall motion abnormalities with a higher sensitivity in patients with prior myocardial infarction. The centerline method had highest sensitivity for the right coronary artery bed (55%). The radial method (45%) and the video intensity based technique (95%) had the highest sensitivity for regions supplied by the left anterior descending artery.

A new video intensity based wall motion analysis technique

A new computerized video intensity based method to evaluate regional wall motion for a frame by frame analysis has been developed. A region of interest is defined, and its average time-intensity curve is computed for the cardiac cycle. For each time interval the video intensity for a pixel in the region of interest is correlated with the average for the whole ventricle and its slope and correlation coefficient are calculated to derive two functional images. This technique utilizes images either from levophase or direct opacification of the left ventricle, and it is insensitive to RR-interval changes.

The hibernating myocardium

The hibernating myocardium refers to resting LV dysfunction due to reduced coronary blood flow that can be partially or completely reversed by myocardial revascularization and/or by reducing myocardial oxygen demand. It is different from the stunned myocardium. Methods for its detection are not yet perfect. Hibernating myocardium has been demonstrated to be present in several clinical subgroups of patients; however, currently its full clinical presence and impact are not adequately defined.

Variability and reproducibility of quantitative left ventricular angiography

To evaluate the reproducibility of left ventricular angiography for the assessment of left ventricular (LV) function and regional wall motion, two ventriculographies were performed in the 30 degrees right anterior oblique (RAO) projection, at 15-minute intervals, in 19 patients undergoing coronary angiography. Heart rate, left ventricular systolic pressure, and end-diastolic pressure were measured 15 minutes after the first angiography returned to the baseline values (71.0 +/- 14.1 vs. 72.2 +/- 15.5 beats/minute, 153.6 +/- 18.0 vs. 152.8 +/- 19.9 mm Hg, 21.7 +/- 8.6 vs. 20.9 +/- 7.3 mm Hg, respectively). Global and regional LV performance was analyzed by two observers with a computer-assisted technique. Intraobserver mean variation of end-diastolic volume and ejection fraction was less than 3% of the control value. Interobserver mean variations for the same parameters were less than 4% of control values. For both observers, there was no significant variation of LV end-diastolic volume and ejection fraction from one study to the other. Under stable hemodynamic conditions, the mean observed variations were, depending on the observer, 5-6% of the control value for LV end-diastolic volume and 5% for ejection fraction. Analysis of segmental wall motion was also highly reproducible. The mean intraobserver variation (% of control value) of wall motion ranged from 4.4% to 9.2%, depending on the sectors studied. The mean interobserver variation, whatever the sector, ranged from 6.9% to 13.5%.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of ionic contrast medium on the movement of acutely ischemic and nonischemic canine myocardium

Regional function assessed by ventriculography may be influenced by the hemodynamic effects of rapidly injecting ionic contrast medium. The importance of this after acute coronary occlusion was examined in eight open-chest, anesthetized dogs. The left anterior descending artery was ligated while sonomicrometric segment lengths in the ischemic (IZ) and nonischemic zones (NZ) were measured. Sodium methylglucamine diatrizoate (Renografin-76, 1 ml/kg) was rapidly injected over 3 seconds. Fifteen minutes later, the left ventricular end-diastolic pressure (LVEDP) was rapidly increased to the level reached during injection. Injecting the contrast increased the LVEDP (7.3 +/- 2.5 to 20.1 +/- 2.9 mm Hg, p less than 0.0001) to the same extent as raising LVEDP (7.6 +/- 2.5 to 10.1 +/- 2.9 mm Hg, p less than 0.0001). Injecting the contrast medium increased IZ total percent systolic shortening (% delta L) (-3.90 +/- 4.43% to -2.68 +/- 4.77%, p less than 0.001) by decreasing isovolumic bulging (-6.68 +/- 4.09% to -5.49 +/- 3.33%, p less than 0.001) with little change in ejection % delta L. NZ total % delta L tended to increase (19.03 +/- 6.53% to 19.94 +/- 6.27%, p = 0.015) because of augmented ejection % delta L (13.12 +/- 2.51% to 13.71 +/- 3.10%, p = 0.017) by the Starling mechanism. Increasing the LVEDP had the same effect on IZ and NZ regional shortening as injecting contrast. Thus regional shortening after acute coronary occlusion is affected by the changes in loading conditions with ionic contrast ventriculography.(ABSTRACT TRUNCATED AT 250 WORDS)

Automatic ventricular edge detection for determination of left ventricular volumes, ejection fraction and regional ejection fractions from first pass radioisotope angiography

An automated method for detection of left ventricular (LV) outline (including the aortic and mitral valve planes) was developed for measurements of end-diastolic volume (EDV), end-systolic volume (ESV), global ejection fraction (EF), and regional EFs from first pass radioisotope ventriculography. The procedure includes: (1) interpolative background subtraction, (2) construction of gradient images, (3) automatic detection of valve planes, and (4) automatic radial search of LV outlines. The correlation between contrast angiography and Tc-99m first pass study was r = 0.84 (SEE = 23.4) for EDV, r = 0.93 (SEE = 12.8) for ESV, r = 0.84 (SEE = 6.91) for EF (via counts) and r = 0.80 (SEE = 8.56) for EF (via area-length method). Tests of intra-observer, inter-observer and inter-study variability revealed low level of variability. The results showed the potential of the automation of data processing for first pass radioisotope ventriculography.

Left ventricular imaging by digital subtraction angiography

Digital radiography is a rapidly developing new approach to cardiovascular imaging that converts radiographic and fluoroscopic video images into digital format for subsequent image enhancement analysis, and storage. Left ventriculography can be performed by this method using either intravenous or low-dose intraventricular contrast administration. Advantages over standard radiography include reduced radiation and contrast medium burden, visualization of very low contrast medium concentrations, and an image format that can be directly analyzed by quantitative techniques. As these cardiac applications are developed and improved archiving is implemented, it is likely that the digital left ventriculography will replace standard cardiac angiography.

[Value of 2-D echocardiography in the detection of stress-induced wall-motion abnormalities in coronary heart disease--a comparison with biplane cineventriculography]

To determine the accuracy of echocardiography in assessment of exercise-induced wall motion abnormalities, the results of stress-echocardiography were compared with exercise-cineventriculography. In 56 consecutive patients biplane cineventriculography at rest and immediately after supine bicycle exercise was performed. Cross-sectional echocardiography was obtained using the apical 2- and 4-chamber view for LV imaging under identical exercise conditions. In 6 of the 56 patients 2-D echo, in 8 patients LV-angio, and in 2 patients both methods were of inadequate quality during exercise. Thus, in 40 patients (34 patients had coronary artery disease) local wall motion of 360 wall segments was analysed. 49 segments (14%) of 24 patients showed exercise-induced ischemic wall motion abnormalities during cineventriculography. Only 24 of these 49 asynergics (49%) were also detected by 2-D-echo. Using cross-sectional echocardiography, ischemia related wall motion abnormalities were best detected laterally and septaly, whereas apical asynergies were identified in 3 of 12 segments only. Thus, the clinical value of exercise 2-D echo as a screening method in patients suspected to have coronary artery disease is limited and restricted to patients with excellent visualization of the left ventricular endocardium.

A comparison of traditional wall motion assessment and quantitative shape analysis: a new method for characterizing left ventricular function in humans

To forego the need to arbitrarily choose coordinate, reference, and indexing systems and to make other assumptions mandated by traditional methods of measuring wall motion, a technique of regional function analysis based on shape characteristics and pattern recognition was developed. The method is based on curvature analysis, a fundamental shape parameter, and is adaptive to the complex geometry of cineangiographic ventricular images. Quantitative shape parameters were compared to a standard method of regional function analysis (center-line method) in 130 patients. Quantitative shape and wall motion indexes showed a positive correlation over a broad range of normal and abnormal function (r = 0.748, p less than 0.001). Overall sensitivity and specificity for categorization of regional function were not statistically different for either technique. Within regions, however, shape criteria were more specific in categorizing inferior zones than anterior zones and were more often abnormal in the presence of mild regional abnormalities that were not located in the apical region. In conclusion, shape analysis and pattern recognition techniques can be used to forego dependence on the numerous assumptions and approximations required by traditional wall motion techniques, while providing performance characteristics that are similar to, and in some instances better than, traditional approaches. Incorporation of shape information in assessments of regional function provides a more comprehensive evaluation that includes the important visual cues used by experienced observers or "experts."

Diverging effects of postextrasystolic potentiation on left ventricular segmental wall motion in coronary heart disease

The effects of postextrasystolic potentiation (PESP) on regional left ventricular (LV) wall motion were evaluated in 40 coronary artery disease (CAD) patients. Of the 40 CAD patients, 20 had a prior myocardial infarction and 20 had a history of angina pectoris. PESP was obtained by applying programmed atrial stimulation during LV angiography, in a way that basal cycle length, premature beat, and postextrasystolic pause were almost identical in all patients. Segmental wall motion was evaluated by calculating regional ejection fraction (EF) of 5 different areas with a computerized method before and after the premature beat. The results were compared to those obtained in a group of 8 normal subjects. LV areas were classified as normokinetic, mildly hypokinetic, severely hypokinetic, and hyperkinetic, on the basis of their regional EF in respect to normals, and classified as "responder" (R) and "nonresponder" on the basis of the magnitude of the increase of regional EF with PESP. Of a total of 200 areas 129 were normokinetic (68% R), 45 were mildly hypokinetic (78% R), 17 severely hypokinetic (76% R), and 9 were hyperkinetic (78% R). Infarcted patients had a higher percentage of hypokinetic areas in basal conditions (p less than 0.001), however, the percentage of hypokinetic areas that responded to PESP was not significantly different from noninfarcted patients. In CAD patients, as a whole, a significant direct correlation was found between basal regional EF and regional EF after PESP (r = 0.88, p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Sources of subjective variability in the assessment of left ventricular regional wall motion from contrast ventriculograms

Intraobserver and interobserver variability in the subjective interpretation of angiographic regional wall motion was quantitated in 135 contrast left ventriculograms showing a wide range of normal and abnormal cardiac function, and the effects of rating-scale complexity and myocardial regional differences were examined. Three experienced observers separately graded endocardial motion on a 6-point scale (0 = normal to 5 = dyskinesia) in each of 5 regions. Scores were also tabulated on a 3-point scale and as normal or abnormal. Average intraobserver agreement (2 evaluations per observer) was 68% using the 6-point scale, 86% using the 3-point scale and 90% for normal/abnormal. Interobserver agreement (3 observers) was 47% for exact agreement using the 6-point scale, 75% using the 3-point scale and 80% for normal/abnormal. Interobserver agreement was 84% within a range of 1 wall motion grade on the 6-point scale. Subjectively normal wall motion was most frequent in the 2 basal segments and least frequent in the apical and anterolateral segments. Disagreements were most frequent in the latter 2 segments, but when normal segments were excluded, these interregional differences disappeared. Thus, intraobserver and interobserver agreement is higher than previously reported, and may exceed 80%. Variability depends on whether regional wall motion is normal, but is also affected by the complexity of the rating scale. The distinctions implied by a 6-point subjective rating scale are probably not reliable, but variability is greatly reduced by use of a simplified scoring system.

Could inspiratory apnea disturb left ventricular volume assessment by contrast angiography?

To assess the influence of postinspiratory apnea on the measurement of the left ventricular volumes, contrast ventriculography was performed on 19 patients during spontaneous breathing and then in postinspiratory apnea. Data obtained were similar for end diastolic volumes (81 +/- 29 ml/m2 vs. 83 +/- 25; NS), end systolic volumes (35 +/- 20 ml/m2 vs. 34 +/- 19; NS), systolic index (46 +/- 13 ml/m2 vs. 49 +/- 12; NS), and ejection fraction (0.57 +/- 0.11 vs. 0.59 +/- 0.12; NS). Postinspiratory apnea suppressed the overlapping of the left ventricle with abdominal viscera in 15 of 17 patients. Diaphragmatic immobility permitted the assessment of regional left ventricular function in all 19 patients. However, pressures recorded in inspiratory apnea can no longer be compared to a transmural pressure, and, to assess ventricular compliance, intrapleural pressure must be measured simultaneously. We conclude that left ventricular volume assessment by contrast ventriculography is not disturbed by inspiratory apnea. This maneuver improves the quality of the images and allows a better evaluation of left ventricular segmental function. Spontaneous breathing can be recommended to simplify left ventricular compliance study.

Left ventricular dysfunction in patients with angina pectoris and normal coronary angiograms

Left ventricular function was assessed in 201 patients who presented with angina pectoris and who were subsequently found to have completely normal coronary angiograms. Left ventricular angiograms from 187 patients were suitable for analysis of systolic regional wall motion; 121 were found to be normal and 66 had a total of 115 hypokinetic segments. Patients with hypokinesia had a significantly higher left ventricular end systolic volume and a significantly lower left ventricular ejection fraction and exercise capacity than those in whom regional wall motion was normal. Thirty one per cent of patients with normal wall motion and 30% of those with hypokinesia had a resting left ventricular end diastolic pressure greater than 15 mm Hg. There were significantly more smokers in the group with hypokinetic segments. Thus of patients with angina and normal coronary angiograms, 25% had evidence of left ventricular systolic dysfunction, 20% had evidence of diastolic dysfunction, and 11% had evidence of both systolic and diastolic dysfunction. The results suggest that smoking may be associated with left ventricular regional wall motion abnormalities.

Prospective comparison of exercise digital subtraction and exercise first pass radionuclide ventriculography

In order to test the comparative sensitivities of first-pass radionuclide and digital subtraction ventriculography in detecting wall motion abnormalities during exercise, 29 patients referred for coronary angiography were submitted to both types of stress ventriculograms. Resting and exercise ventriculograms by both techniques were reviewed by independent observers and the five equal ventricular wall segments were graded as normal, mildly, moderately, severely hypokinetic, akinetic, or dyskinetic. Of the 29 patients, 24 had arteriographically defined ischemic potential (at least greater than 50% obstruction of a major coronary artery supplying viable myocardium). Exercise digital subtraction ventriculography correctly identified 17 (71%) of these by a worsening of wall motion during exercise, while radionuclide ventriculography identified only eight (33%) by the wall motion response. When either a worsening of wall motion or the failure to increase ejection fraction by at least 5 points were used as criteria for an abnormal test, the sensitivities of digital and radionuclide ventriculographies were 96% and 79%, respectively. Though the number of patients without ischemic potential (5 patients) was too small to judge the relative specificities, digital subtraction ventriculography appears to be more sensitive than radionuclide ventriculography in identifying exercise-induced wall motion abnormalities and in predicting coronary occlusions.

Cardiac applications of digital subtraction angiography

Recent developments in digital computer technology have enabled direct digital acquisition of radiographic images at spatial and temporal resolutions similar to that of cineradiography. Initially intended as a means of performing peripheral angiography, digital subtraction angiography has been increasingly applied to cardiac catheterization procedures. Advantages of cardiac digital subtraction angiography include the capabilities to: immediately replay, magnify and enhance angiographic studies during coronary artery interventions, perform left ventriculography with peripheral contrast injections and direct left ventriculography with substantially reduced contrast doses, perform bypass graft visualization using aortic root contrast injection, assess relative regional coronary blood flow and facilitate the quantification of ventriculographic and coronary stenosis parameters. Clinical comparisons of standard cineradiographic and digital angiographic studies have demonstrated very similar results.

Regional left ventricular wall motion assessment: comparison of two-dimensional echocardiography and radionuclide angiography with contrast angiography in healed myocardial infarction

The diagnostic ability of radionuclide angiography (RNA) and 2-dimensional echocardiography (2-D echo) to assess regional left ventricular (LV) wall motion was compared with contrast angiography in 52 patients with healed myocardial infarction. After 5 patients were excluded for inadequate 2-D echocardiographic studies, the LV images of 47 patients obtained by all 3 techniques were divided into 7 segments for analysis. Both 2-D echo and RNA showed close agreement with contrast angiography in assessing normal vs abnormal wall motion in the anterobasal (91%, 91%), anterolateral (87%, 79%) and posterolateral segments (77%, 79%). The sensitivity in detecting wall motion abnormalities was highest for 2-D echo and RNA in the anterolateral (83%, 77%) and apical (95%, 84%) segments and lowest for the inferior segment (48%, 48%). Specificity of 2-D echo and RNA was high, ranging from 94% in the anterolateral segment to 71% in the septal segment for 2-D echo, and from 91% in the inferior segment to 81% in the posterobasal and septal segments for RNA. Major discrepancies with contrast angiography occurred more often in the posterobasal, posterolateral, inferior and septal LV segments. Thus, in comparison with contrast angiography, 2-D echo and RNA are reliable for detecting anterior and apical wall motion abnormalities, but relatively less sensitive for detecting wall motion abnormalities involving the inferior, posterobasal and posterolateral LV segments.

Two-dimensional echocardiography versus surface electrocardiography for the diagnosis of acute non-Q wave myocardial infarction

The initial two-dimensional echocardiogram (2DE) and electrocardiogram (ECG) of 50 consecutive patients with chest pain and a possible acute non-Q wave myocardial infarction (MI) were compared to each other to determine the value of 2DE in this type of acute MI. The ECG markers for a non-Q wave MI were (1) greater than or equal to 0.15 mV ST segment depression, (2) ST segment elevations with reciprocal ST segment depression, and (3) new symmetrical deep T wave changes as compared to a recent preadmission ECG. The 2DE was considered positive for MI if akinesia, dyskinesia, or severe hypokinesia was seen in one or more left ventricular segments. The sensitivity, specificity, and predictive value of the 2DE as compared to the ECG was 66% and 52%, respectively (sensitivity); 91% and 95%, respectivity (specificity); and 91% and 94%, respectively (predictive value). Statistically, there were no differences in the proportion of patients who had a positive 2DE as compared to the proportion of patients who had a positive ECG (p greater than 0.2). The ECG and 2DE results were combined and the sensitivity increased to 76% but the specificity decreased to 86%. Myocardial infarction size was not significantly different in infarcted subjects who had a positive 2DE (395 +/- 125 IU/L) as compared to those who had a negative 2DE (727 +/- 187 IU/L, p greater than 0.1).

Comparison of three semiautomatic methods for determination of left ventricular ejection fraction from gated cardiac blood pool images

A number of computer programs exist for the determination of ejection fraction from gated blood pool images. Three commercially available algorithms were compared on the same radionuclide data from 50 catheterized patients. The methods used were: (1) simple thresholding, (2) second derivative edge determination, and (3) a combination of these two. There was good correlation with catheterization ejection fraction for all three methods using smoothed data [r = 0.781, 0.77, 0.84 respectively (P less than 0.01)]. However, interobserver variance was significantly decreased (P less than 0.01) by use of the second derivative method when compared with the other two methods and catheterization. Thus, if accuracy and low interobserver variance are required, then a combination of a second derivative and thresholding method is preferable.

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.

Transient myocardial ischemia with minimal electrocardiographic changes: an echocardiographic study in patients with Prinzmetal's angina

Kn patients with Prinzmetal's angina, episodes of transient T wave abnormalities (T abn) are often documented in addition to the typical episodes of ST segment elevation (ST). As the interpretation of these minor ECG changes is still uncertain, we investigated if transient T abn are associated with reversible ventricular asynergies, similar to episodes with ST. For this purpose an ECG lead and a two-dimensional echocardiographic projection, which showed clear-cut changes during previous episodes of ST, were simultaneously monitored in five patients with Prinzmetal's angina for a total of 13 hours and 20 minutes. In all patients, the 30 episodes of ST recorded were all accompanied by reversible ventricular asynergies. Furthermore, in four of these patients, 14 episodes of T abn (peaking, flattening, or the appearance of a diphasic T wave) were recorded. All T abn were associated with reversible asynergies, as detected by three independent observers. The mechanical impairment occurred in the same ventricular wall both during ST and during T abn. During T abn the degree of mechanical impairment appeared less severe (hypokinesia in 12 and akinesia in two episodes) than during ST (hypokinesia in one, akinesia in 25, and dyskinesia in four episodes) (p less than 0.001). The duration of asynergies was less during T abn (107 +/- 76 seconds) than during ST (169 +/- 83 seconds) (p less than 0.05). Chest pain was reported in 5 of 14 episodes of T abn (36%) and in 20 of 30 (66%) episodes of ST (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Assessment of potentially salvageable myocardium during acute myocardial infarction: use of postextrasystolic potentiation

Twenty-three patients with evolving acute myocardial infarction (AMI) undergoing catheterization for thrombolytic therapy had interventional contrast ventriculography using programmed atrial stimulation. Postextrasystolic (PES) potentiation was present in 67% of infarct-related segments up to 9 hours after the onset of AMI. The presence of segmental potentiation was not related to time from onset of pain to ventriculography, initial ejection fraction, presence of collaterals, left ventricular end-diastolic pressure or the PES delay. In 18 patients reperfusion was successful using intracoronary streptokinase an average of 6.2 hours after the onset of AMI; in these patients repeat contrast ventriculography was performed an average of 11 days after AMI. Improved chronic segmental ventricular function was predicted by the presence of collaterals to the infarct-related artery at the time of acute catheterization (p = 0.02), but was best predicted by analysis of acute PES potentiation (p less than 0.0001). The predictive value of PES analysis was highest in segments without collaterals. Thus, atrial stimulation is safe during AMI and analysis of segmental ventricular function shows potentially viable myocardium up to 9 hours after the onset of AMI. In addition, analysis of PES segmental function can predict chronic function if reperfusion is successful, especially in segments without collaterals. PES ventriculographic analysis may allow prospective determination of which patients during AMI are most likely to benefit from acute thrombolytic therapy.

Right ventricular imaging with digital subtraction angiocardiography using intraventricular contrast injection

Angiocardiography is of considerable value in the dimensional analysis of the right ventricular (RV) cavity, but conventional angiocardiography requires large amounts of contrast medium. In this study digital subtraction angiocardiography was applied to biplane RV projections of 25 children with congenital heart disease after direct injection of a small dose of contrast medium. Volume measurements were compared with those obtained by conventional angiocardiography. The amount of contrast medium required was reduced to 30%, flow rate to 57% and ventricular ectopic activity to 60% of that used in conventional angiocardiography, and the degree of radiation exposure was reduced considerably. There was a good correlation for end-diastolic (r = 0.996) and end-systolic volume (r = 0.990) determined with both techniques. Digital subtraction angiography after selective RV injection allows accurate volume measurements of the right ventricle in children with congenital heart disease. The main benefits of this method are reduction of the amount of contrast medium, flow rate during injection, radiation and ventricular ectopic activity.

Analysis of left ventricular regional motility: a comparison of different methods

Multiple gated blood pool (MUGA) and contrast ventriculographic studies were performed within 24 h in 80 patients, 20 with 120 normokinetic wall segments and 60 with wall motion abnormalities in 239 of 360 wall segments. Three methods of evaluation of the radionuclide ventriculograms were compared with the results of the biplane contrast ventriculography which served as a standard: (1) qualitative analysis of the cine mode, (2) analysis of parametric scans (amplitude and phase images) and the phase histogram obtained by Fourier analysis, (3) quantitative determination of regional ejection fraction. Normal values were obtained from 20 patients with normal wall motion in the contrast angiogram. The overall sensitivity for the detection of wall motion abnormalities of high degree was 96% for method 1, 95% for method 2, and 90% for method 3, for those of low degree 72% for method 1, 63% for method 2, and 75% for method 3. Combining methods 2 and 3 the sensitivity was increased to 99% for high grade and to 81% for low grade wall motion abnormalities. The two methods showed a complementary effect because of different sensitivities in dependence of the localization of the wall motion abnormality. Although a high efficiency for the evaluation of left ventricular function was provided by the qualitative analysis of the cine mode the combination of Fourier analysis and the determination of regional ejection fraction should be preferred. It increases the sensitivity for the detection of wall motion abnormalities. Moreover, it offers quantitative data which improve the reproducibility and decrease the observer variability.

Reproducibility of left ventricular volume determinations with use of a semi-automated system

Reliability of a computer-assisted system for determination of left ventricular volumes was judged by multiple measurements of rotation ellipsoids, cadaver hearts, and cineangiograms from patients. The volume measurements in cadaver hearts provided a volume correction factor necessary for reproducible results. Variation coefficient for intraobserver and interobserver variability did not exceed 2.3% when calculated using rotation ellipsoids and was highest at 12.0% for the end-systolic volumes derived from patient films. When appropriate calibration methods are employed, different observers can make reliable left ventricular volume measurements aided by such systems.