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

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

81mKr equilibrium radionuclide ventriculography for the assessment of right heart function

Right heart 81mKr equilibrium radionuclide ventriculography was used to derive right ventricular ejection fraction (RVEF) in 12 healthy male volunteers. Anatomical lung subtraction using 99mTc-MAA perfusion scintigraphy was compared with conventional background correction and the effect of imaging projection on the techniques of image analysis evaluated. Both intra and inter observer variability were reduced by anatomical lung subtraction when compared to conventional background correction. In the right anterior oblique (RAO) projection, background corrected RVEF was lower than lung subtracted RVEF - 0.544 +/- 0.05 and 0.612 +/- 0.08 (mean +/- SD) (P less than 0.02). Lung subtracted RVEF in the anterior projection was lower than that with background correction (P less than 0.05) and lower than lung subtracted RVEF in the RAO projection (P less than 0.001). We conclude that optimal separation of right heart structures is achieved in the RAO projection and that reproducibility of the analytical technique is improved by anatomical lung subtraction.     

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

A semi-automated, variable-region-of-interest method of analysis was used to measure both global and segmental left ventricular (LV) and global right ventricular (RV) contraction with ECG-gated first-pass and equilibrium radionuclide ventriculography. Normal values were defined in 20 healthy volunteers, and in 24 symptomatic patients, the results were compared with right anterior oblique (RAO) contrast left ventriculography. The global LV ejection fraction (LVEF) obtained by equilibrium imaging in the left anterior oblique (LAO) projection correlated closely with the results obtained by the gated first-pass method in the RAO projection (r=0.95) and those obtained with contrast left ventriculography (r=0.94); furthermore, the interobserver variability was small (r=0.985). The normal values for LVEF obtained using radionuclide techniques and contrast ventriculography did not differ, but with the equilibrium radionuclide method, the RV ejection fraction (RVEF) values were underestimated in comparison to those obtained by the RAO gated first-pass technique. In five patients with localised inferior segmental akinesis at contrast angiography, the RAO first-pass cine display demonstrated a corresponding wall-motion abnormality in all cases, but LAO equilibrium cine displays did so in only one out of five patients. For segmental quantitation of LV contraction, a computer programme defined the ventricular edge, divided the RAO LV images into five segments and determined both the segmental area contraction (SAC) and the counts-based segmental ejection fraction (SEF). Radionuclide SAC measurements correlated very strongly with SEF measurements (r=0.94–0.99). Both radionuclide SAC and radionuclide SEF correlated well with contrast angiographic SAC, except in the inferobasal segment. Mean radionuclide SAC (29%) for the five segments did not differ from mean contrast SAC (29%). This combined protocol enables rapid and accurate biventricular assessment of global and segmental contraction. Significant diagnostic value exists in combining these two acquisition protocols in specific clinical situations.     

Localization of exercise-induced myocardial ischemia with single view and biplanar radionuclide ventriculography: validation in single vessel coronary disease

The ability of single view and biplanar radionuclide ventriculography (RVG) to determine the location of myocardial ischemia during maximal graded supine bicycle exercise was assessed in 50 patients with chest pain, no prior myocardial infarction, and a single coronary stenosis of greater than or equal to 50% luminal diameter narrowing at coronary angiography. A biplane collimator was used so that both right anterior oblique (RAO) gated first-pass and left anterior oblique (LAO) equilibrium RVG could be performed at rest and exercise. Results were compared with those obtained using 4-view 201Tl myocardial scintigraphy in the same patients. Regional wall motion abnormalities (WMA) and 201Tl perfusion defects were detected and assigned to individual coronary vessels by agreement between at least two of three independent observers, who read all studies blinded along with those from control subjects with chest pain but no angiographically significant coronary artery disease. When scintigraphic abnormalities were detected, both biplanar RVG (36/39 = 92%) and 201Tl (25/25 = 100%) were more frequently correct in predicting the stenosed vessel than single view LAO RVG (24/32 = 75%) (P less than 0.05). At RVG only inferior WMA, in the RAO view, predicted right coronary stenosis. Only posterolateral WMA, in the LAO view, predicted left circumflex stenosis. Thus biplanar, but not single view, LAO exercise RVG is a reasonable alternative to exercise 201Tl for localizing exercise-induced ischemic abnormalities to individual coronary stenoses.     

81mKr equilibrium radionuclide ventriculography for the assessment of right heart function

Right heart^81mKr equilibrium radionuclide ventriculography was used to derive right ventricular ejection fraction (RVEF) in 12 healthy male volunteers. Anatomical lung subtraction using^99mTc-MAA perfusion scintigraphy was compared with conventional background correction and the effect of imaging projection on the techniques of image analysis evaluated. Both intra and inter observer variability were reduced by anatomical lung subtraction when compared to conventional background correction. In the right anterior oblique (RAO) projection, background corrected RVEF was lower than lung subtracted RVEF - 0.544 ±0.05 and 0.612±0.08 (mean ± SD) (P<0.02). Lung subtracted RVEF in the anterior projection was lower than that with background correction (P<0.05) and lower than lung subtracted RVEF in the RAO projection (P < 0.001). We conclude that optimal separation of right heart structures is achieved in the RAO projection and that reproducibility of the analytical technique is improved by anatomical lung subtraction.     

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

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

Oblique projections in aortography following blunt thoracic trauma

We report a patient with innominate artery false-aneurysm formation following blunt trauma to the thorax. Aortography in the standard anteroposterior and left anterior oblique (LAO) projections failed to delineate the injury. Its true extent was only demonstrable in the right anterior oblique (RAO) projection. When the clinical history and a chest radiograph suggest a high likelihood of injury to the aorta or great vessels, routine aortography may need to be performed in both the LAO and RAO projections.     

小型猪冠状动脉造影方法的建立

目的建立小型猪的冠状动脉造影的方法,为小型猪的冠状动脉造影术方法提供依据。方法20头小型猪,采用动脉直视下插管以及利用人的左冠和右冠导管进行小型猪的冠状动脉造影术。分别于正位、左前斜位、右前斜位下造影。结果股动脉通路置管成功率高。正位下易对右冠进行超选,右前斜位下易对左冠进行超选。结论本文提供了小型猪冠状动脉造影的方法。     

Accuracy of predicted orthogonal projection angles for valve deployment during transcatheter aortic valve replacement

BackgroundMulti-detector computed tomography (MDCT) predicted orthogonal projection angles have been introduced to guide valve deployment during transcatheter aortic valve replacement (TAVR). Our aim was to investigate the accuracy of MDCT prediction methods versus actual angiographic deployment angles.MethodsRetrospective analysis of 2 currently used MDCT methods: manual multiplanar reformations (MR) and the semiautomatic optimal angle graph (OAG). Paired analysis was used to compare the 2-dimensional distributions and means.ResultsWe included 101 patients with a mean (±SD) age of 81 ± 9 years. The MR and OAG methods were used in 46 and 55 patients, respectively. A ≥5% change from the predicted MDCT range in left anterior oblique/right anterior oblique (LAO/RAO) and the cranial/caudal (CRA/CAU) angle occurred in 42% and 58% of patients, respectively. The mean predicted versus actual deployment angles were significantly different (CRA/CAU: -2.6 ± 11.5 vs. -7.6 ± 10.7, p < 0.001; RAO/LAO 8.1 ± 10.9 vs. 9.5 ± 10.6, p = 0.048; respectively). The MR method resulted in a more accurate CRA/CAU angle (CRA/CAU: -4.6 ± 11.1 vs. -6.5 ± 11.8, p = 0.139; RAO/LAO 7.4 ± 11.2 vs. 10.4 ± 11.2, p = 0.008; respectively), whereas the use of the OAG resulted in a more accurate RAO/LAO angle (CRA/CAU: -0.9 ± 10.8 vs. -9±11.2, p < 0.001; RAO/LAO 9.05 ± 10.6 vs. 8.5 ± 9.9, p = 0.458; respectively). For the entire cohort, the 2-dimensional distributions and means of the predicted versus the actual angles were significantly different from each other (p < 0.001). We repeated our analysis using both MDCT methods and demonstrated similar results with each method.ConclusionsCurrently used MDCT methods for TAVR implantation angles are significantly modified before actual valve deployment. Thus, further refinement of these prediction methods is required.     

Localization of exercise-induced myocardial ischemia with single view and biplanar radionuclide ventriculography: validation in single vessel coronary disease

The ability of single view and biplanar radionuclide ventriculography (RVG) to determine the location of myocardial ischemia during maximal graded supine bicycle exercise was assessed in 50 patients with chest pain, no prior myocardial infarction, and a single coronary stenosis of 50% luminal diameter narrowing at coronary angiography. A biplane collimator was used so that both right anterior oblique (RAO) gated first-pass and left anterior oblique (LAO) equilibrium RVG could be performed at rest and exercise. Results were compared with those obtained using 4-view ²⁰¹Tl myocardial scintigraphy in the same patients. Regional wall motion abnormalities (WMA) and ²⁰¹Tl perfusion defects were detected and assigned to individual coronary vessels by agreement between at least two of three independent observers, who read all studies blinded along with those from control subjects with chest pain but no angiographically significant coronary artery disease. When scintigraphic abnormalities were detected, both biplanar RVG (36/39=92%) and ²⁰¹Tl (25/25=100%) were more frequently correct in predicting the stenosed vessel than single view LAO RVG (24/32=75%) (P<0.05). At RVG only inferior WMA, in the RAO view, predicted right coronary stenosis. Only posterolateral WMA, in the LAO view, predicted left circumflex stenosis. Thus biplanar, but not single view, LAO exercise RVG is a reasonable alternative to exercise ²⁰¹Tl for localizing exercise-induced ischemic abnormalities to individual coronary stenoses.This work was supported by a Postgraduate Medical Research Scholarship from the National heart Foundation of Australia (Canberra), and by the Alfred Hospital Whole Time Medical Specialists (Melbourne)     

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

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

Investigation of human right ventricular cast specimens

Fifty human right ventricular cast specimens were subjected to X-ray cineangiography in biplane right anterior oblique and left anterior oblique (RAO/LAO) projection. From the silhouettes seen in the two projection planes we estimated areas and lengths using a lightpen minicomputer system and calculated the volumes using various methods. The calculated volume values were compared with the true values determined by water displacement. The methods were then arranged is order of decreasing accuracy. Criteria for judging model quality were the mean squared deviations, correlation coefficient, and residual variance. The most accurate calculation of the right ventricular volume was obtained with Ferlinz' method and our own empirical approach.     

Thick maximum intensity projections for the assessment of left ventricular function with 64-slice computed tomography

OBJECTIVE: The objective of this study was to assess the accuracy of thick maximum intensity projections (MIP) from computed tomography (CT) data sets mimicking projection images from biplane ventriculography for evaluation of left ventricular (LV) parameters. MATERIALS AND METHODS: Fifty-eight patients underwent 64-slice CT. Multiphase images were reconstructed in 10% steps of the RR interval. MIP images (70-mm thickness) of the contrast-enhanced LV in fixed 30 degrees right anterior oblique (RAO)/60 degrees left anterior oblique (LAO) and in adapted short-/long-axis planes were reconstructed. LV parameters were calculated using the area-length method formula. Three-dimensional assessment with semiautomated software served as reference standard. RESULTS: Use of thick MIP reconstructions had a high intermethod reliability (86-94%) compared with the 3-dimensional approach. Smaller measurement errors were found for thick MIP reconstructions in adapted short-/long-axis planes. A significant projection error (3.0%, P < 0.001) of thick MIP reconstructions was found using fixed 30 degrees RAO/60 degrees LAO compared with adapted short-/long-axis reconstructions. CONCLUSION: Thick MIP reconstructions with adapted short-/long-axis planes allow an accurate assessment of LV parameters compared with the established 3-dimensional method.     

Standardization and quantification of radionuclide solid gastric-emptying studies.

The purposes of this investigation were to standardize and validate a simple quantitative method for performing radionuclide solid gastric emptying that can be used for any dual-head gamma-camera and to establish reference values. METHODS: After eating a solid meal (egg sandwich) labeled with a radionuclide, 20 healthy volunteers (9 male, 11 female) underwent a 90-min gastric-emptying study performed with a triple-head gamma-camera. Two sets of 3 simultaneous projections were acquired sequentially for 30 s each: anterior, right posterior oblique (RPO), left posterior oblique (LPO), posterior, left anterior oblique (LAO), and right anterior oblique (RAO), and this sequence was repeated continuously for 90 min. Time-activity curves were generated using a gastric region of interest for each of the views as well as the conjugate-view geometric mean (GM) data for the anterior/posterior, LAO/RPO, and RAO/LPO combinations. Quantitative parameters were determined: percentage gastric emptying (%GE) at 90 min, half-time (min) based on an exponential fit, and clearance rate (%/min) based on a linear fit. Reference values were determined on the basis of a 95% confidence interval of the t distribution. The results were statistically analyzed and compared. RESULTS: The %GE reference values were greater for the anterior/posterior GM (>or=33%) than for the LAO (>or=31%) and anterior (>or=30%) GMs. The 3 %GE GM methods, the 3 exponential-fit GM methods, and the 3 linear-fit GM methods had high correlation coefficients (r >or= 0.874), and with only a single exception, there was no statistical difference among them. The LAO method and LAO/RPO GM mean method correlated strongly (r = 0.900) and had similar mean values (52% vs. 51%) and reference values (29% vs. 30%). All 3 methods of GM quantification also correlated strongly, and there was no significant difference among them. CONCLUSION: We have described and validated a simple method for radionuclide solid gastric emptying that can be used with a dual-head gamma-camera. We recommend the anterior/posterior GM method and have established reference values (>or=33%).     

Estimation of right ventricular ejection fraction by means of 99Tcm-macroaggregates.

A method is described for assessing right ventricular ejection fraction (RVEF) by means of 99Tcm-macroaggregates (MAA). The method consists of performing, in right anterior oblique (RAO) projection, a direct ECG-gated data acquisition over 120 s, as soon as the intravenous administration of the tracer is started. The activity returning to the left heart being negligible, background is limited to the lung activity overlapping the right ventricle. The distribution of lung activity in the gated frames is, however, exactly the same as that in the lung perfusion image, it can therefore be subtracted using static lung scintigraphy acquired directly after the gated study. Considering the count density distributions in the corrected end-diastolic (ED) and end-systolic (ES) frames and the first harmonic phase and amplitude images, ED and ES RV regions of interest (ROIs) are delineated for the calculation of RVEF. It has been shown that using 5 mCi 99Tcm-MAA, the ED count obtained is similar to that usually observed during a 20 mCi 99Tcm first-pass study. Intraobserver variation is acceptable and there is a good correlation between the RVEF calculated by this method and that obtained by means of a steady-state ECG-gated 81Krm technique. As the method presents similar advantages to those offered by 81Krm while using 99Tcm, it constitutes, in our opinion, a good approach for estimating RVEF in routine clinical practice.     

Evaluation of exposure dose to patients undergoing catheter ablation procedures—a phantom study

The aim of this study was to evaluate entrance skin dose (ESD), organ dose and effective dose to patients undergoing catheter ablation for cardiac arrhythmias, based on the dosimetry in an anthropomorphic phantom. ESD values associated with mean fluoroscopy time and digital cine frames were in a range of 0.12–0.30 Gy in right anterior oblique (RAO) and 0.05–0.40 Gy in left anterior oblique (LAO) projection, the values which were less than a threshold dose of 2 Gy for the onset of skin injury. Organs that received high doses in ablation procedures were lung, followed by bone surface, esophagus, liver and red bone marrow. Doses for lung were 24.8–122.7 mGy, and effective doses were 7.9–34.8 mSv for mean fluoroscopy time of 23.4–92.3 min and digital cine frames of 263–511. Conversion coefficients of dose-area product (DAP) to ESD were 8.7 mGy/(Gy·cm²) in RAO and 7.4 mGy/(Gy·cm²) in LAO projection. The coefficients of DAP to the effective dose were 0.37 mSv/(Gy·cm²) in RAO, and 0.41 mSv/(Gy·cm²) in LAO projection. These coefficients enabled us to estimate patient exposure in real time by using monitored values of DAP.     

用电极导管标测对Koch三角的X线影像测定在慢径消融中的价值

目的测定Koch三角的x线影像学上的大小及在慢径消融中的价值.方法27例房室结双径路并折返性室上速的患者,用冠状静脉窦口及希氏束标记Koch三角的部位,分别用左前斜(LA0)45 及加头位和足位20 ,右前斜(RAO)30 及加用头位和足位20 测量Koch三角的高度,以20mn为界将Koch三角分为大小两组.结果Koch三角有较差异,以LAO45 显示最小,RA0+足位显示最大.结论小Koch三角组慢径多分布位置低,消融时可参考RA0+足位;大Koch三角组消融位置多在中下1/3以下区域.     

A new, simple and precise method for the determination of right ventricule forward ejection fraction in first-pass radionuclide cardiography

A new method is presented for the determination of right ventricular ejection fraction (RVEF) in first-pass radionuclide cardiography. The method is simple to apply and it provides RVEF values with an experimental standard deviation of 3.4% over the whole range of right ventricular ejection fractions. The method determines RVEF from analysis of time-activity curves from regions of interest (ROIs) over representative portions of the right atrium and the pulmonary artery (RVEFRAPA). Hence, the problem of demarcation of the right ventricle from adjacent structures is avoided. RVEFRAPA was 0.658 +/- 0.067 (mean +/- 1 S.D.) in a normal group of 36 adult women. This value was not significantly different from the RVEF of 0.641 +/- 0.072 (mean +/- 1 S.D.) determined by separate areas over the right ventricle in the end-diastole and end-systole (RVEFRVSA). In a repeatability study comprising 25 subjects covering a wide range of RVEF values, the standard deviation of RVEFRAPA was 4.4 times smaller than that of RVEFRVSA. The left ventricular ejection fraction (LVEF) determined in the equilibrium gated radionuclide cardiography following the first-pass study was 0.692 +/- 0.065 (mean +/- 1 S.D.) for the normal group. Hence, LVEF is slightly higher than RVEF in normals.     

The two-view radionuclide ventriculogram. Advantages of the LPO view.

This report is a prospective study of 33 male patients who underwent both contrast ventriculography (CVG) and radionuclide ventriculography (RVG) within a 24-hour period. Expert, blinded observers graded the left ventricle's regional wall motion (RWM) in the left anterior descending (LAD), left circumflex (LCx), and posterior descending arterial (PDA) distributions on right anterior oblique (RAO), and left anterior oblique (LAO) CVGs, and on anterior (ANT), LAO, 70 degrees left anterior oblique (LAO70), and left posterior oblique (LPO) RVGs. When statistically compared with CVG RWM standard data, RVG studies composed of LAO and LPO views were equal to the RVG studies composed of ANT, LAO, and LAO70 views in assessment of the LAD and LCx distributions. The RVG with LAO and LPO views was superior to the RVG with ANT, LAO, LAO70 in the detection of the posterior descending artery RWM. The authors conclude that accurate assessment of RWM is efficiently performed with the RVG composed of LAO and LPO views.     

Determination of optimal fluoroscopic angulations for aorto-coronary ostial interventions from coronary computed tomography angiography

BackgroundAn optimal aorto-coronary angiographic projection, characterized by an orthogonal visualization of the proximal coronary artery, is crucial for interventional success. We determined the distribution of optimal C-arm positions and assessed their feasibility by invasive coronary angiography.MethodsOrthogonal aorto-coronary ostial angulations were determined in 310 CT data sets. In 100 patients undergoing subsequent invasive angiography, we assessed if the CT-predicted angulations were achievable by the C-arm system. If the predicted projection was not achievable due to mechanical constraints of the C-arm system, the most close, achievable angulation was determined. Patient characteristics were analyzed regarding the distribution of optimal angulations and its feasibility by the C-arm system.ResultsFor the left ostium, CT revealed a mean angulation of LAO 23 ?± ?21°/cranial 25 ?± ?23° (90% of patients with a LAO/cranial angulation, 3% LAO/caudal, 4% RAO/cranial, 3% RAO/caudal) and were achievable by the C-arm system in 87% of patients. For the right ostium, the mean CT-predicted orthogonal angulation was LAO 36 ?± ?37°/cranial 36 ?± ?51° (84% LAO/cranial, 2% LAO/caudal, 14% RAO/caudal) and achievable by the C-arm system in 45% of patients. For the left ostium, a higher body weight was associated with a steeper LAO/cranial angulation being less feasible by the C-arm system due to mechanical constraints.ConclusionsOrthogonal aorto-left coronary angulations show a relative narrow distribution predominately in LAO/cranial position whereas a wider range of angulations was found for the right coronary ostium. The feasibility of CT-predicted angulations by the C-arm system is more restricted for the right than the left coronary ostium.