Right Anterior Oblique Projection Research Articles

Kualitas Informasi Anatomi Radiograf pada Pemeriksaan Sternum dengan Variasi Penyudutan Arah Sinar

Background: The sternum's radiographic examination involves the use of Right Anterior Oblique (RAO) and Lateral projections. However, if a patient cannot undergo RAO projection, Left Posterior Oblique (LPO) projection in the supine position and adjusting the central ray angle are alternatives. On another note, deviations from perpendicular alignment among the central ray, image receptor, and object can lead to distortions in shape, impacting image quality. Hence, a study is conducted to investigate the impact of beam angle variations on the quality of anatomical information in sternum radiographs to identify the optimal angle that yields the highest quality anatomical information in sternum radiographs. Methods: This research was quantitative research employing an experimental methodology. Data collection involved employing a single-body phantom, which underwent three exposures at each of the specified angle variations Results: Based on the results of the Kruskal Wallis test, there were significant differences in the quality of radiographic anatomic information (p value 0.05). The angle with the most optimal quality of radiographic anatomical information was an angle of 25° to the left with a mean rank value of 11.00. Conclusions: There was a significant difference in the quality of radiographic anatomic information (p value 0.05). The angle with the most optimal quality of radiographic anatomic information was the angle with the highest mean rank value, which was an angle of 25° to the left.

Revisiting right anterior oblique projections for the triangle of Koch: implications from computed tomography

BackgroundVariability in the anatomy and orientation of the triangle of Koch (TK) complicates ablation procedures involving the atrioventricular (AV) node. We used CT angiography (CTA) to assess the anatomical TK orientation, the CS ostium direction, and the relationship between the two, and we validated an individualized CS-guided projection during ablation procedures.MethodsIn 104 patients without structural heart disease undergoing computed tomography (CT) angiography, TK orientations were determined in relation to the coronary sinus ostium (CSo) as well as two standard right anterior oblique (RAO) projection angles (30o and 45o) commonly used in ablation procedures.ResultsA CS-guided RAO projection (RAOCS) was shown to best track the orientation of the TK compared to RAO30° and 45°, with TK orientation strongly correlating with the CSo direction (r = 0.86, P < 0.001). In addition, the mean relative difference between the angle of the CSo and TK orientation was 5.54 ± 0.48°, consistent with a reduction in the degree of image shortening compared to traditional RAOs. Moreover, in vivo validation following ablation revealed that using a CS-guided projection limited the degree of on-screen image shortening compared to both the RAO30° and 45° in 25 patients with catheter ablation procedures.ConclusionIn hearts with a normal structure, the CSo direction offers a reliable predictor of the TK orientation which can be used to guide the projection of the TK during ablation procedures.

Coronary Sinus Phlebography in Cardiac Resynchronization Therapy Patients: Identifying and Solving Demanding Cases

Cardiac resynchronization therapy (CRT) improves symptoms and reduces morbidity and mortality in select heart failure patients but remains challenging to deploy widely because of difficult or unsuccessful coronary sinus (CS) access in up to 10% to 15% of patients. This report describes the radiological and anatomical aspects for improving CS catheterization and left ventricular (LV) lead positioning, focusing on the radioscopic and anatomical aspects, based on phlebography, to identify demanding cases in patients with dilated cardiomyopathy referred for CRT implantation. Anatomical and radiological aspects were explored in the anteroposterior, 30° left anterior oblique, and 30° right anterior oblique (RAO) views. In total, 117 phlebographies were performed in 39 consecutive procedures (one reintervention). Access to the CS was successful 37 times (94.9%). The most difficult cases were complicated by issues related to the altered spatial orientation of the CS ostium toward the tricuspid annular plane (TAP), which was best perceived in the 30° RAO projection and occurred in 37% of patients. One of two catheterization failures that occurred was caused by anomalous coronary venous drainage into the left atrium. Final LV lead positioning was successful in 36 (92.3%) of 39 procedures. More severe heart failure and worse LV ejection fraction did not translate into greater difficulty in LV lead implantation. As such, understanding anatomical and radiological relationships is the key to successful LV lead positioning. RAO projection can be particularly useful in the assessment of demanding CRT implant cases, especially when the CS ostium pointed to the TAP.

Using gastric emptying scintigraphy to evaluate antral contractions and duodenal bolus propagation.

Our aim was to investigate the feasibility of measuring antral contractions and duodenal bolus propagation (DBP) during dynamic antral contraction scintigraphy (DACS) as an assessment of antro-pyloro-duodenal coordination (APDC). Gastric emptying scintigraphy (GES) with DACS was performed with Tc-99m sulfur colloid (SC) using increasing doses of 74 MBq (2 mCi) for 10 subjects, 185 MBq (5 mCi) for 11, and 370 MBq (10 mCi) for 11. DACS was performed for 10 min after static images at 0, 30, 60, 120, 180, and 240 min in anterior and right anterior oblique (RAO) projections. Best projection and lowest dose of Tc-99m SC were assessed visually. DBP were quantified utilizing duodenal activity peaks from a region of interest in the first portion of the duodenum. DBP was better visualized in the RAO projection than anterior projection and using 185 MBq (5 mCi) and 370 MBq (10 mCi) compared with 74 MBq (2 mCi). DBP showed infrequent and irregular bolus transfers from the antrum to the duodenum. Antral activity peaks at 60 min averaged 2.91 ± 0.66 per minute and duodenum bolus peaks 0.36 ± 0.18 per minute (ratio 0.36/2.91 = 0.12). DBP activity peaks can be measured during GES with DACS but requires a 185-MBq (5 mCi) dose of Tc-99m SC radiolabeled test meal for adequate DBP signal detection and is better imaged in RAO than anterior projection. DBPs over the first 60 min postmeal ingestion are infrequent with only 12% of the antral contractions propagating into the duodenum. This methodology appears promising to assess APDC.NEW & NOTEWORTHY This study shows that duodenal bolus propagations after meal ingestion can be measured during gastric emptying scintigraphy using dynamic scintigraphy. Duodenal bolus propagation over the first 60 min postmeal ingestion are infrequent with only 12% of the antral contractions propagating into the duodenum. This methodology appears promising to assess antropyloroduodenal coordination in patients with unexplained symptoms of upper gastrointestinal dysmotility.

Radiation Exposure of Operators Performing Transesophageal Echocardiography During Percutaneous Structural Cardiac Interventions

BackgroundTransesophageal echocardiography operators (TEEOP) provide critical imaging support for percutaneous structural cardiac intervention procedures. They stand close to the patient and the associated scattered radiation. ObjectivesThis study sought to investigate TEEOP radiation dose during percutaneous structural cardiac intervention. MethodsKey personnel (TEEOP, anesthetist, primary operator [OP1], and secondary operator) wore instantly downloadable personal dosimeters during procedures requiring TEE support. TEEOP effective dose (E) and E per unit Kerma area product (E/KAP) were calculated. E/KAP was compared with C-arm projections. Additional shielding for TEEOP was implemented, and doses were measured for a further 50 procedures. Multivariate linear regression was performed to investigate independent predictors of radiation dose reduction. ResultsIn the initial 98 procedures, median TEEOP E was 2.62 μSv (interquartile range [IQR]: 0.95 to 4.76 μSv), similar to OP1 E: 1.91 μSv (IQR: 0.48 to 3.81 μSv) (p = 0.101), but significantly higher than secondary operator E: 0.48 μSv (IQR: 0.00 to 1.91 μSv) (p < 0.001) and anesthetist E: 0.48 μSv (IQR: 0.00 to 1.43 μSv) (p < 0.001). Procedures using predominantly right anterior oblique (RAO) and steep RAO projections were associated with high TEEOP E/KAP (p = 0.041). In a further 50 procedures, with additional TEEOP shielding, TEEOP E was reduced by 82% (2.62 μSv [IQR: 0.95 to 4.76] to 0.48 μSv [IQR: 0.00 to 1.43 μSv] [p < 0.001]). Multivariate regression demonstrated shielding, procedure type, and KAP as independent predictors of TEEOP dose. ConclusionTEE operators are exposed to a radiation dose that is at least as high as that of OP1 during percutaneous cardiac intervention. Doses were higher with procedures using predominantly RAO projections. Radiation doses can be significantly reduced with the use of an additional ceiling-suspended lead shield.

Sleeve Gastrectomy: Correlation of Long-Term Results with Remnant Morphology and Eating Disorders.

Remnant dimension is considered one of the crucial elements determining the success of sleeve gastrectomy (SG), and dilation of the gastric fundus is often believed to be the main cause of failure. The main outcome of this study is to find correlations between remnant morphology in the immediate post-operative stage, its dilation in years, and the long-term results. The second purpose aims to correlate preoperative eating disorders, taste alteration, hunger perception, and early satiety with post-SG results. Remnant morphology was evaluated, in the immediate post-operative stage and over the years (≥2years), through X-ray of the oesophagus-stomach-duodenum calculating the surface in anteroposterior (AP) and right anterior oblique projection (RAO). Presurgery diagnosis of eating disorders and their evaluation through "Eating Disorder Inventory-3" (EDI3) during follow-up were performed. Change in taste perception, sense of appetite, and early satiety were evaluated. Patients were divided into two groups: "failed SGs (EWL<50%) and "efficient SGs" (EWL >50%). There were a total of 50 patients (37 F, 13 M), with mean age 52years, preoperative weight 131±21.8kg, and BMI 47.4±6.8kg/m2. Post-operative remnant mean dimensions overlapped between the two groups. On a long-term basis, an increase of 57.2 and 48.4% was documented in the AP and RAO areas respectively. In "failed" SGs, dilation was significantly superior to "efficient" SGs (AP area 70.2 vs 46.1%; RAO area 59.3 vs 39%; body width 102% vs 41.7%). Preoperative eating disorders were more present in efficient SGs than in failed SGs with the exception of sweet eating. There were no significant changes to taste perception during follow-up. Fifty-two percent of efficient SGs vs 26% of failed SGs reported a persistent lack of sense of hunger; similarly, 92.5 vs 78% declared the persistence of a sense of early satiety. The two groups did not statistically differ as far as all the variables of the EDI3 are concerned. On a long-term basis, the remnant mean dilation is around 50% compared to the immediate post-operative stage but failed SGs showed larger remnant dilation than efficient SGs and, in percentage, the more dilated portion is the body of the stomach. As far as all the EDI3 variables obtained are concerned, the two groups did not statistically differ. Of all eating disorders, sweet eating seems to be weakly connected to SG failure.

Anatomical Discrepancy Between The Coronary Sinus and the Mitral Annulus by Fluoroscopy

Background and Objectives: Intracardiac electrocardiograms (ECGs) from the coronary sinus (CS) provide important information for identifying a left-sided bypass tract. However, a previous study revealed an anatomical discrepancy between the CS and mitral annulus (MA) in cadaver hearts. The purpose of this study was to evaluate the anatomical relationship between the CS and MA in the living body by using fluoroscopy. Subjects and Methods: We analyzed patients who had an ablation for 42 left-sided bypass tracts and one paroxysmal atrial fibrillation. A left atriogram was performed during the ablation by using a pigtail catheter via the transseptal approach. The distances between the CS and MA were measured at 30° right anterior oblique (RAO) and 60° left anterior oblique (LAO) projections at the end of ventricular systole and diastole. Results: The distances between the CS and MA at the RAO projection were 9.74±3.50, 3.86±2.58, and 9.02±6.04 mm during systole and 12.89±5.59, 3.97±3.24, and 10.71±4.12 mm during diastole at the proximal, middle, and distal CS, respectively. The distances between the CS and MA at the LAO projection were 6.84±2.77, 1.80±1.51, and 4.57±3.24 mm during systole and 9.91±3.25, 4.21±3.59, and 7.02±3.12 mm during diastole at the proximal, middle, and distal CS, respectively. Conclusion: An anatomical discrepancy was detected between the CS and MA in most cases. Therefore, intracardiac ECGs of the CS cannot exactly localize left-sided bypass tracts. Key words: Coronary Sinus; Mitral Annulus; Fluoroscopy

Optimized separation of left and right liver lobe in dynamic 99mTc-mebrofenin hepatobiliary scintigraphy using a hybrid SPECT-CT scanner

To correctly display the left and right liver lobe separately on dynamic projection scintigraphy, it is essential to adjust the collimator to the angle of the plane between the two liver lobes. We propose an optimized protocol for separating left and right liver lobe in (99m)Tc-mebrofenin hepatobiliary scintigraphy in a hybrid SPECT-CT device. The protocol uses the inherent attenuation correction low-dose CT (AC-CT) for individually adjusting gamma camera head angulation. The results of this protocol are compared with hypothetical results based on previous MRI, fixed angle, and traditional frontal projection. The absolute and relative degrees of overlapping volume between left and right liver lobe parenchyma for frontal projection, 45° right anterior oblique (RAO) projection, RAO angulation based on previously acquired MRI, and RAO based on the AC-CT were measured in 14 patients who underwent (99m)Tc-mebrofenin hepatobiliary scintigraphy. Relative degree of overlap was 31.3±15.2% for frontal projection, 8.2±6.5% for 45° RAO, 5.5±3.5% for RAO based on previous MRI, and 3.6±2.5% for RAO based on AC-CT. The relative overlap of RAO projections based on previous MRI was significantly lower than for frontal projection (p<0.05). Use of the angle from the prior AC-CT, however, resulted in an even lower degree of overlap (p<0.05). Performing (99m)Tc-mebrofenin hepatobiliary scintigraphy using RAO detector alignment with an angle derived from a prior CT obtained in the SPECT-CT scanner can significantly reduce the degree of overlap between right and left liver lobe. If SPECT-CT is not available, previous CT or MRI or a fixed angle of 45° may be used.

Pre-Procedural Imaging of Aortic Root Orientation and Dimensions: Comparison Between X-Ray Angiographic Planar Imaging and 3-Dimensional Multidetector Row Computed Tomography

We sought to examine whether contrast-enhanced multidetector row computed tomography (MDCT) allows prediction of X-ray angiographic planes for the root angiogram in the context of transcatheter aortic valve implantation. Understanding of aortic root orientation relative to the body axis is critical for precise positioning of the stent/valve during transcatheter aortic valve implantation. Forty patients with severe aortic stenosis underwent conventional X-ray angiography and contrast-enhanced MDCT of the aortic root. Oblique MDCT images of the aortic root, corresponding to X-ray angiographic left anterior oblique (LA)/right anterior oblique (RAO) projections, were created. The cranial/caudal angulation was compared between angiographic and reformatted MDCT images. In addition, root diameter measurements were compared. The cranial angulation in the LAO X-ray angiograms (mean LAO: 39+/- 8, n = 38) and matched MDCT images were not significantly different (cranial: 25 +/- 7 vs. 23 +/- 8; p = 0.214). There was a small but significant difference between the caudal angulation in the RAO angiogram (mean RAO: 25 +/- 5, n = 40) and matched CT images (caudal: 21 +/- 9 vs. 29 +/- 10; p = 0.002). The annulus diameter in the LAO projection was not significantly different between X-ray angiography and contrast-enhanced MDCT (2.3 +/- 0.3 vs. 2.4 +/- 0.3; p = 0.052), whereas there was a small but significant difference in the annulus diameter in RAO projections between angiography and MDCT (2.4 +/- 0.3 vs. 2.2 +/- 0.3; p = 0.029). Pre-procedural contrast-enhanced MDCT imaging of the aortic root allows prediction of X-ray angiographic planes and contributes to planning of the transcatheter aortic valve implantation.

Optimal fluoroscopic projections for angiographic imaging of the pulmonary vein ostia: lessons learned from the intraprocedural reconstruction of the left atrium and pulmonary veins

Electrical isolation of the pulmonary veins (PVs) is the cornerstone of the ablative treatment of atrial fibrillation. Selective angiography of the PVs in standard fluoroscopic projections is often used for intraprocedural identification of PVs and their ostia. Variable spatial orientation and significant variability of PV anatomy are important limitations of this imaging approach. Sixty patients undergoing a PV isolation procedure received intraprocedural rotational angiography and three-dimensional reconstruction of the left atrium (LA) and PVs. For each patient, 33 angiographic projections were independently evaluated [right anterior oblique (RAO) 80 degrees to left anterior oblique (LAO) 80 degrees, in steps of 5 degrees] by two physicians in order to identify the optimal projections of the PV ostia according to the following definition: Sagittal plane: (i) clear identification of both superior and inferior segments of the LA-PV junction and (ii) no overlapping between LA (and/or left atrial appendage) and PV ostium. Frontal plane: (i) clear identification of all four quadrants of the PV ostium and (ii) fluoroscopic angles at which the maximal horizontal ostial diameter is visualized. A successful reconstruction of the LA and all PVs was obtained in 58 (97%) patients. An optimal ostial projection in a sagittal plane was identified for all four PVs. The optimal ostial projection was RAO 5 degrees for the right superior PVs in 57 out of 58 patients (98%), RAO 55 degrees for the right inferior PVs in 54 out of 58 patients (93%), LAO 45 degrees for the left superior PVs in 46 out of 58 patients (80%), and LAO 60 degrees for the left inferior PVs in 48 out of 58 patients (83%). An optimal ostial projection in a frontal plane was identified only for the inferior PVs. The optimal ostial projection was LAO 40 degrees for the right inferior PVs in 55 out of 58 patients (95%) and RAO 45 degrees for the left inferior PVs in 51 out of 58 patients (88%). If selective angiography is to be used to delineate anatomy and location of the PV ostia to guide PV isolation, different fluoroscopic projections are required for different PVs. The preselected RAO and LAO projections proposed in our study result in optimal angiographic projections of all PV ostia in at least one plane in the majority of patients.

Measurement of Left Ventricular Mass by Contrast Ventriculography

Elevated left ventricular mass (LVM) has been shown to be an important predictor of adverse cardiac events. Calculation of LVM using contrast ventriculography, as described by Rackley, involves measuring left ventricular wall thickness in a single plane, with assumptions made about ventricular geometry. We hypothesized that a modification of the Rackley method, involving multiple measurements of left ventricular (LV) wall thickness in 2 orthogonal planes, may add value in the determination of LVM in patients with LV remodeling and dysfunction. The LVM was determined in 24 patients with LV dysfunction who had undergone both cardiac magnetic resonance imaging (CMRI) and contrast left ventriculography. Right anterior oblique (RAO) and left anterior oblique (LAO) still frames in diastole were used to measure LV length, chamber area, and wall thickness. From these variables, LV volume, myocardial volume, and LVM were calculated. The LVM calculations using an average wall thickness from the LAO and RAO projections were compared with LVM measured by CMRI. Eighty eight percent of patients had hypertension, 100% had coronary artery disease, and mean left ventricular ejection fraction by contrast left ventriculography was 41 +/- 14%. Averaging left ventricular wall thickness from RAO and LAO projections using biplane ventriculography for LVM calculation yielded a strong correlation (r = 0.77, p < 0.01) with LVM calculated from CMR. In patients with left ventricular dysfunction, biplane left ventricular wall thickness measurements for contrast ventriculography LVM calculations render a strong correlation with LVM calculated by CMRI.

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.

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.

Right ventricular ejection fraction determined in three projections.

The right ventricular ejection fraction (RVEF) was successively determined in three projections in ten healthy volunteers aged 28-53, mean 37 years, with a first-pass technique using 99Tcm-labelled red blood cells and a gamma camera coupled to a computer. In the anterior-posterior projection (AP) the mean RVEF was 39.3%, range 26-49%, in the left anterior oblique (LAO) 43.7% (36-58), and in the right anterior oblique (RAO) 44.5% (36-54). These mean values do not differ significantly (P = 10%). The results from one of the subjects were withdrawn, as they deviated markedly from the general pattern, and the data were reanalysed from the remaining 9 subjects. Now the mean RVEF in the AP projection was 38.2%, which is significantly lower (P = 1%) than the corresponding RVEF of 44.3% in the LAO projection and of 45.2% in the RAO projection. Our results suggest that when using the classic first-pass technique, the right ventricle histograms will in any projection be influenced by the activity in the right atrium and the large vessels.

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.

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)

Left ventricular volumes by single-plane cineangiography: In vivo validation of the kennedy regression equation

This study was performed to assess the accuracy and reliability of the regression equations of Kennedy et al and Wynne et al in the quantitation of single plane left ventricular (LV) volumes. In 15 patients with normal LV function and without intracardiac shunting or valvular insufficiency, gated equilibrium blood pool scintigraphy was performed simultaneously with the measurement of cardiac output (by thermodilution), after which left ventriculography was performed in the 30 ° right anterior oblique (RAO) projection. From the scintigraphically determined LV ejection fraction (EF) and the ther-modilution-measured stroke volume (SV), absolute LV volumes were calculated. The cineangiographic LV volumes obtained with the regression equation of Kennedy et al closely approximated those calculated by scintigraphy/thermodilution, whereas the volumes determined using the regression equation of Wynne et al were larger (p<0.05) than the calculated volumes. In 204 patients without intracardiac shunting or valvular insufficiency, SV was measured by the Fick or indicator dilution methods, after which single-plane left ventriculography was performed in the 30 ° RAO projection. In the 83 patients without coronary artery disease with normal (n = 69) or depressed (n = 14) LVEF, cineangiographic SV (obtained using the regression equation of Kennedy et al) closely approximated forward SV. Similarly, this relation was excellent in the 142 patients whose LVEFs were ≥ 0.50. In contrast, in the 48 patients whose LVEFs were <0.50 and who had extensive segmental wall motion abnormalities, there was a poor relation between cineangiographic SV (obtained using the regression equation of Kennedy et al) and forward SV. Thus, LV volumes can be measured accurately by single-plane cine-angiography in a 30 ° RAO projection using the area-length method and the regression equation of Kennedy et al, but the reliability of these volumes is poor in persons with extensive segmental LV dysfunction.

Echoventriculography -- a simultaneous analysis of two-dimensional echocardiography and cineventriculography.

Two-dimensional echocardiography underestimates left ventricular volume compared with cineventriculography. To exclude the influence of difference in heart rate, blood pressure, respiration phases and any effect of the contrast material on left ventricular function, simultaneous studies of two-dimensional echocardiography and cineventriculography-echoventriculography were performed in 46 patients. Apical two-dimensional echocardiograms in the right anterior oblique (RAO) equivalent view were recorded before and during cineventriculography in the 30 degrees RAO projection. End-diastolic and end-systolic volumes (EDV and ESV) were calculated using a disc method with a semiautomatic computer system. The echo transducer position relative to the left ventricular apex and long axis was analyzed. For EDV determined by two-dimensional echocardiography and cineventriculography, the linear regression equation was y = 0.659x + 0.8, SEE = +/- 26.2 ml, r = 0.907. For ESV, the regression equation was y = 0.571x + 17.8, r = 0.938, SEE = +/- 18.6 ml, and for ejection fraction (EF) it was y = 0.606x + 13.0, r = 0.803, SEE = +/- 9.1%. Injection of contrast material resulted in only a small increase of stroke volume, caused by an increase of EDV as analyzed by echoventriculography. In all but two patients, the transducer position was found to be anterior and superior to the left ventricular anatomic apex, as evaluated by filming the echo transducer position during cineventriculography in 46 patients in the 30 degrees RAO projection and in 15 patients consecutively in the 60 degrees left anterior oblique and 30-40 degrees cranial projections. Thus, tangential cuts of the ventricle resulted in underestimation of diameters, long axis and ventricular volumes. These methodologic problems are exacerbated by slice-thickness artifacts. Furthermore, different outlining of left ventricular contour -- outer border of ventricular trabeculae for cine ventriculography and inner border for two-dimensional echocardiography -- seemed to result in underestimation of volume by echocardiography.

Clinical evaluation of emission tomography using seven-pinhole collimator: improved detection of perfusion defect by the addition of the right anterior oblique projection.

The clinical efficacy of thallium emission myocardial tomography using a seven-pinhole collimator in the right anterior oblique (RAO) projection was evaluated. Myocardial tomography in left anterior oblique (LAO) and RAO projections was performed following planar thallium perfusion imaging at rest in 11 patients with myocardial infarction. The RAO tomogram was useful, especially in detecting apical perfusion defects, while the LAO tomogram was useful in detecting inferior and anteroseptal wall defects. For the four patients without an apparent myocardial perfusion defect seen on the planar image, the LAO tomogram showed a perfusion defect in three, and the RAO tomogram also showed the defect in three. One or the other of the two views demonstrated the defect for all 11 patients. The myocardial tomogram in the RAO projection, providing a sufficiently high-quality and high-contrast image, gives useful information complementary to the findings of the commonly used LAO projection in the evaluation of myocardial infarctions.