Planar Radionuclide Ventriculography Research Articles

Clinical validation of the planar radionuclide ventriculography in patients with right ventricular dysfunction

ObjectivesGated radionuclide ventriculography (RNV) may be used for the evaluation of the right ventricular function. However, the accuracy of the method should be clinically validated in patients suffering from diseases with specific pathology of the right ventricle (RV) and with possible left ventricular (LV) interaction. MethodsThree groups of 15 patients each, diagnosed with arrhythmogenic right ventricular dysplasia (ARVD), pulmonary artery hypertension (PAH) or atrial septal defect (ASD) were compared to a group of normal subjects. The parameters for both ventricles were evaluated separately (ejection fractions: LVEF and RVEF, and intraventricular synchronism quantified as phase standard deviation: LVPSD and RVPSD) as well as the relation or interdependence of the right to left ventricle (RV/LV volume ratio, LV/RV ejection fraction and stroke volume ratios, and interventricular synchronism).All the variables as a whole were analyzed to identify groups of patients according to their functional behaviour. ResultsSignificant differences were found between the patients and control group for the RV function while the LV function remained mostly within normal limits.When the RV function was considered, the control group and ASD patient group showed differences regarding the ARVD and PAH patients. On evaluating the RV/LV ratios, differences were found between the control group and the ASD group. In the PAH patients, LV function showed differences in relation to the rest of the groups. ConclusionRNV is a reliable clinical tool to evaluate RV function in patients with RV abnormality.

Clinical validation of the planar radionuclide ventriculography in patients with right ventricular dysfunction

Gated radionuclide ventriculography (RNV) may be used for the evaluation of the right ventricular function. However, the accuracy of the method should be clinically validated in patients suffering from diseases with specific pathology of the right ventricle (RV) and with possible left ventricular (LV) interaction. Three groups of 15 patients each, diagnosed with arrhythmogenic right ventricular dysplasia (ARVD), pulmonary artery hypertension (PAH) or atrial septal defect (ASD) were compared to a group of normal subjects. The parameters for both ventricles were evaluated separately (ejection fractions: LVEF and RVEF, and intraventricular synchronism quantified as phase standard deviation: LVPSD and RVPSD) as well as the relation or interdependence of the right to left ventricle (RV/LV volume ratio, LV/RV ejection fraction and stroke volume ratios, and interventricular synchronism). All the variables as a whole were analyzed to identify groups of patients according to their functional behaviour. Significant differences were found between the patients and control group for the RV function while the LV function remained mostly within normal limits. When the RV function was considered, the control group and ASD patient group showed differences regarding the ARVD and PAH patients. On evaluating the RV/LV ratios, differences were found between the control group and the ASD group. In the PAH patients, LV function showed differences in relation to the rest of the groups. RNV is a reliable clinical tool to evaluate RV function in patients with RV abnormality.

Abstract 136: Changes of Myocardial Contractility in Hypertensive Patients With Persistent Atrial Fibrillation Receiving Propafenone

Objective: To study the effect of propafenone 450 mg daily on myocardial contractility in hypertensive patients with persistent atrial fibrillation (AF). METHODS: Study included 32 hypertensive patients with persistent AF, aged from 39 to 63 years (median age 58,6±5,3 years), 14 of them (44%) were men and 18 (56%) were women. Sinus rhythm was restored within 24 hours after the oral loading dose of propafenone 600 mg in all the patients. All the patients received propafenone 450 mg daily to prevent AF paroxysms during the next 12 months. Planar equilibrium radionuclide ventriculography was performed in all the patients to assess myocardial function. Initial study was performed in 32 (100%) patients within the first 3 days after sinus rhythm restoration, the follow-up imaging study was carried out in 18 (56%) patients with sustained sinus rhythm after 12 months. Results: After 12 months of treatment with propafenone, 18 (56%) of hypertensive patients remained in sinus rhythm. Recurrent episodes of AF were registered in 14 (44%) patients during 12 month follow-up period, hence they were excluded from the study. Initial radionuclide ventriculography made after sinus rhythm restoration in hypertensive patients with persistent AF demonstrated myocardial diastolic dysfunction manifested as significant decrease of time to 30% filling and peak LV and RV filling rate. Follow-up study after propafenone treatment during 12 months revealed significant increase in time to 30% filling and peak LV and RV filling rate. Normal values of atrial contribution to left and right ventricular filling were observed in patients maintaining sinus rhythm during 12 month treatment period with propafenone (p<0.05). Systolic parameters and volume of both ventricles remained normal and showed no significant changes. Left and right ventricular ejection fraction before the treatment start and after propafenone administration during 12 months remained within the normal range. Conclusion: Propafenone 450 mg daily administered for recurrent AF prevention does not affect left and right ventricular contractility. Sinus rhythm maintenance for 12 months in hypertensive patients with persistent AF restores atrial contractility and improves ventricular diastolic function.

A single dose of erythropoietin in ST-elevation myocardial infarction

Cardioprotective effects of erythropoietin (EPO) have been shown in experimental and smaller clinical studies. We performed a prospective, multicentre, randomized trial to assess the effects of a single high dose of EPO after primary coronary intervention (PCI) for an ST-elevation myocardial infarction (STEMI). Methods and results Patients with a successful PCI for a first STEMI were randomized to receive either standard medical care alone, or in combination with a single bolus with 60,000 IU i.v. of epoetin alfa within 3 h after PCI. Primary endpoint was left ventricular ejection fraction (LVEF) after 6 weeks, assessed by planar radionuclide ventriculography. Pre-specified secondary endpoints included enzymatic infarct size and major adverse cardiovascular events. A total of 529 patients were enrolled (EPO n = 263, control n = 266). At baseline (before EPO administration), groups were well-matched for all relevant characteristics. After a mean of 6.5 (± 2.0) weeks, LVEF was 0.53 (± 0.10) in the EPO group and 0.52 (± 0.11) in the control group (P = 0.41). Median area under the curve (inter-quartile range) after 72 h for creatinine kinase was 50 136 (28 212-76 664)U/L per 72 h in the EPO group and 53 510 (33 973-90 486)U/L per 72 h in the control group (P = 0.058). More major adverse cardiac events occurred in the control than in the EPO group (19 vs. 8; P = 0.032). Conclusion A single high dose of EPO after a successful PCI for a STEMI did not improve LVEF after 6 weeks. However, the use of EPO was related to less major adverse cardiovascular events and a favourable clinical safety profile. NCT00449488; http://www.clinicaltrials.gov/ct2/show/NCT00449488?term=voors&rank=2.

Left ventricular volume assessment by planar radionuclide ventriculography evaluated by MRI

Assessment of left ventricular (LV) ejection fraction (LVEF) and LV volume are essential for the evaluation of prognosis in cardiac disease. LVEF and LV volumes can be measured with several imaging modalities, such as magnetic resonance imaging (MRI) or computed tomography; however, these are relatively expensive and time consuming. In contrast, planar radionuclide ventriculography (PRV) for LVEF assessment is a cost-effective, fast, and reliable technique, but PRV for LV volumes calculation is less common. Evaluation of a new hybrid geometrical count-based method (HGCBM) in comparison with two count-based methods (CBMs) and a geometrical method (GM) for the calculation of LV volumes with PRV using MRI as reference. Thirty cardiac patients underwent routine PRV with a standard dose of 500 MBq of Tc-pertechnetate and additional cardiac MRI as reference method. LV volumes of PRV data were calculated by four different methods. The CBMs and GM are based on the assumption that the shape of the LV can be approximated by an ellipsoid or sphere, and the new HGCBM extracts the volume from the projected count rates themselves. All methods underestimated the LV volumes as compared with the MRI-measured volumes. The difference (mean+/-SD) of end-diastolic volume (EDV) between PRV and MRI was 33+/-23 ml for GM, 12+/-26 ml for HGCBM, 50+/-38 ml for CBM1, and 13+/-40 ml for CBM2. The correlation coefficients for EDV between PRV methods and MRI were r = 0.90 for GM and r = 0.85 for HGCBM. The CBMs showed poor correlation r = 0.64 with the MRI data and a high SD. The difference of end-systolic volume (ESV) between PRV and MRI was 23+/-19 ml for GM, 9+/-22 ml for HGCBM, 29+/-29 ml for CBM1, and 9+/-28 ml for CBM2. The correlation coefficients for ESV between PRV methods and MRI were r = 0.955 for GM and r = 0.914 for HGCBM, r = 0.85 for CBM1 and CBM2. Although GM showed a slightly higher correlation than HGCBM, the difference of EDV and ESV between PRV and MRI was much higher for GM in comparison with HGCBM. Both CBMs showed poor agreement with MRI data. PRV using the new HGCMB method in comparison with other methods is an easy and accurate method to determine LV volumes. However, all methods underestimate ESV and EDV slightly as compared with MRI.

The importance of left ventricular function for long-term outcome after primary percutaneous coronary intervention

BackgroundIn the present study we sought to determine the long-term prognostic value of left ventricular ejection fraction (LVEF), assessed by planar radionuclide ventriculography (PRV), after ST-elevation myocardial infarction (STEMI) treated with primary percutaneous coronary intervention (PPCI).MethodsIn total 925 patients underwent PRV for LVEF assessment after PPCI for myocardial infarction before discharge from the hospital. PRV was performed with a standard dose of 500 Mbq of 99mTc-pertechnetate. Average follow-up time was 2.5 years.ResultsMean (± SD) age was 60 ± 12 years. Mean (± SD) LVEF was 45.7 ± 12.2 %. 1 year survival was 97.3 % and 3 year survival was 94.2 %. Killip class, multi vessel-disease, previous cardiovascular events, peak creatin kinase and its MB fraction, age and LVEF proved to be univariate predictors of mortality. When entered in a forward conditional Cox regression model age and LVEF were independent predictors of 1 and 3 year mortality.ConclusionLVEF assessed by PRV is a powerful independent predictor of long term mortality after PPCI for STEMI.

Comparison among tomographic radionuclide ventriculography algorithms for computing left and right ventricular normal limits

Various algorithms have been developed to compute right ventricular (RV) and left ventricular (LV) end-diastolic volumes, end-systolic volumes, and ejection fractions (EF) from tomographic radionuclide ventriculography (TRV). The aims of this investigation were to establish sex-specific normal limits, to determine whether different algorithms produce the same normal values, and to compare TRV normal limits vs for magnetic resonance imaging values in the literature. Fifty-one healthy volunteers (29 men, 22 women) were studied prospectively. All subjects had normal electrocardiograms and echocardiographic examinations, and underwent both planar radionuclide ventriculography and TRV. Four algorithms were used to process TRV data. Normal limits for most functional parameters differed significantly from one algorithm to another. Volumes were greater in men, but no statistically significant differences were found between men and women for LV EF or RV EF values for any method. Normal LV and RV EF and volumes were largely consistent with the literature for cardiac magnetic resonance imaging. Ventricular measurements differ significantly among TRV algorithms. Therefore, it is important to apply sex-specific normal limits that are specific to a given TRV algorithm in interpreting LV and RV EF and volume measurements for each patient.

Comparison of Gated Blood Pool SPECT and Multi-Detector Row Computed Tomography for Measurements of Left Ventricular Volumes and Ejection Fraction in Patients with Atypical Chest Pain: Validation with Radionuclide Ventriculography

Gated blood pool SPECT (GBPS) is an alternative to planar radionuclide ventriculography (PRNV) and offers potential advantages. The aim of this study was to compare GBPS, multi-row detector spiral computed tomography (MDCT), and PRNV for the determination of left ventricular ejection fraction (LVEF) and left ventricular volumes (LV) in subjects with atypical chest pain. Method: Twenty-three consecutive patients (14 men, 9 women; mean age 56.2 ± 9.5 years) referred for MDCT for evaluation of atypical chest pain. All patients underwent PRNV, GBPS, and MDCT at the same day. Results: The mean LVEFs calculated with PRNA (57.3 ± 8.6%), GBPS (55.2 ± 6.6%), and MDCT (56 ± 9.1%) were not statistically different (F value 0.3374, p = 0.715). Comparison of LVEFs from GBPS and MDCT yielded correlation coefficients of 0.5238 (p = 0.0178, 95% CI = 0.1057–0.7845). The correlation of LVEFs between GBPS and PRNV showed a correlation coefficient of 0.8073 (p < 0.0001, 95% CI = 0.5676–0.9209) and 0.6190 (p = 0.0036, 95% CI = 0.2431–0.8333) between MDCT and PRNV. The mean LV end-diastolic volume (EDV) calculated with GBPS (82.7 ± 17.5 ml) was significantly lower than MDCT (106.8 ± 18.5 ml) (p = 0.0001). The mean LV end-systolic volume (ESV) calculated with GBPS (37.2 ± 9.6 ml) was also significantly lower than MDCT (48.1 ± 15.8 ml) (p = 0.012). Comparison of EDV from GBPS and MDCT yielded a correlation coefficient of 0.5220 (p = 0.0182, 95% CI = 0.1033–0.7835). The correlation of ESV between GBPS and MDCT showed a correlation coefficient of 0.6642 (p = 0.0014, 95% CI = 0.3140–0.8553). Conclusion: In conclusion, the LVEF, EDV, and ESV calculated by GBPS correlated significantly with those of obtained with 16-MDCT. In addition, there were no statistical differences of LVEF calculated from PRNV, GBPS, and MDCT. However, with regard to LV, EDV and ESV from GBPS revealed statistically significantly lower than those of MDCT. Also, these results should be addressed whether similar results could also be found in patients with cardiac diseases by the consequent larger population-based study.

Optimizing sequential biventricular pacing using radionuclide ventriculography

Biventricular pacemakers are usually programmed with the default setting of synchronous biventricular pacing, although the ventricles may be paced sequentially. Whether this parameter is important for optimizing resynchronization therapy is not clear. The purpose of this study was to investigate whether sequential pacing acutely improves left ventricular ejection fraction (LVEF) and dyssynchrony and to assess the feasibility of nuclear ventriculography for device optimization. Twenty-seven patients implanted with a biventricular pacemaker or implantable cardioverter-defibrillator for heart failure were studied. LVEF was measured using planar radionuclide ventriculography during simultaneous biventricular pacing and during sequential pacing at four different interventricular intervals ranging from LV-40 (preexciting the left ventricle by 40 ms) to LV+40 (preexciting the right ventricle). Interventricular and intraventricular dyssynchrony were analyzed by phase analysis at each setting. There was great heterogeneity in individual response to VV interval programming. Twenty-four of 27 patients (89%) had significant changes (both favorable and unfavorable) in LVEF at different interventricular delays, with variations of up to 10% in absolute terms. Simultaneous biventricular pacing yielded maximal LVEF in 9 of 27 patients (33%), with a relative increase in LVEF of 18 +/- 14% by optimized sequential pacing in the remaining patients. Interventricular dyssynchrony varied significantly, with least dyssynchrony at the LV-20 setting (P = .024). There were no significant differences in intraventricular dyssynchrony at the different settings. Programming VV intervals has considerable impact on LVEF. However, there is a great degree of variation between patients in response to these settings, requiring individual assessment for device optimization.

The feasibility of repeated left ventricular ejection fraction analysis with sequential single-dose radionuclide ventriculography

Repeated left ventricular ejection fraction (LVEF) analyses with sequential single-dose radionuclide ventriculography might be an interesting technique for monitoring the effect of positive inotropic interventions. The aim of the study was to assess the reproducibility of LVEF measurement with planar radionuclide ventriculography within 3 h, using a standard single dose of radioactive tracer. Sixteen patients underwent routine planar radionuclide ventriculography with a standard dose of 500 MBq of [Tc]pertechnetate and returned after 3 h for a repeat planar radionuclide ventriculography without administration of additional tracer. The average initial LVEF was 35.1+/-18.6%-point (range, 12%-point to 68%-point). The mean difference of the LVEF between the initial planar radionuclide ventriculography and the repeat planar radionuclide ventriculography was 2.8%+/-6.3% (range, -11.8% to 13.3%, P=NS). The correlation between both measurements was significant with a correlation coefficient of 0.995 (P<0.01). Bland-Altman analysis revealed a mean LVEF difference of 0.94%-point between the baseline planar radionuclide ventriculography and the repeat planar radionuclide ventriculography (95% confidence interval: -2.7%-point to 4.5%-point). The visual wall motion assessment showed excellent reproducibility, with a kappa-statistic of 0.98. Repeated radionuclide ventriculography with a 3 h interval using a single standard dose of 500 MBq of [Tc]pertechnetate is highly reproducible and will be useful for monitoring the effect of positive inotropic interventions.

Gated blood pool SPECT for measurement of left ventricular volumes and left ventricular ejection fraction: comparison of 8 and 16 frame gated blood pool SPECT

Gated blood pool SPECT (GBPS) is an alternative to planar radionuclide ventriculography (PRNV) and offers potential advantages. The aim of this study was to compare 8 and 16 frame GBPS for the determination of left ventricular ejection fraction(LVEF) and left ventricular volumes (LV) in subjects underwent two consecutive GBPS. About 66 consecutive patients (30 men, 36 women; mean age 62.3 +/- 10.4 years) referred for PRNV for evaluation of preoperative cardiac risk stratification (n = 40), prechemotherapy cardiac function evaluation (n = 18, breast cancer), and congestive heart failure patients (n = 8). All patients underwent PRNV of 16 frame and GBPS with both of 8 and 16 frame. The mean LVEF calculated with PRNV (58.3 +/- 16.8), showed statistically lower than 8-GBPS (70.6 +/- 17.7), and 16-GBPS (69.9 +/- 16.8) (PRNV vs. 8-GBPS, p < 0.01; PRNV vs 16-GBPS, p < 0.01; 8-GBPS vs 16-GBPS, p > 0.05). The correlation of LVEFS between 8-GBPS and 16-GBPS showed a correlation coefficient of 0.9194 (p < 0.01, 95% CI = 0.8712-0.9500). The mean left ventricular end-diastolic volumes (EDV) calculated with 8-GBPS (83.2 +/- 33.5 ml), and 16-GBPS (88.4 +/- 36.8 ml) showed no statistical differences (p > 0.05). The mean left ventricular end-systolic volumes (ESV) calculated with 8-GBPS (28.1 +/- 31.4 ml), and 16-GBPS (30.5 +/- 33 ml) showed also no statistical differences (p > 0.05). Comparison of EDV from 8 and 16-GBPS yielded a correlation coefficient of 0.7430 (p < 0.01, 95% CI = 0.6108-0.8349). The correlation between ESV of 8-GBPS and 16-GBPS showed a correlation coefficient of 0.9522 (p < 0.01, 95% CI = 0.9228-0.9705). This study demonstrated that the LVEFs of 8-GBPS correlated well with that of 16-GBPS. The LVEF of PRNV was significantly lower than those of 8 and 16-GBPS. Also, left ventricular EDV and ESV of 8-GBPS correlated well with those of 16-GBPS. Also, further studies, involving large lumber patients, should be performed to validate the usefulness of GBPS for the evaluation of left ventricular diastolic function.

Agreement between four available algorithms to evaluate global systolic left and right ventricular function from tomographic radionuclide ventriculography and comparison with planar imaging

Left and right ventricular ejection fractions (LVEF and RVEF) and end-diastolic and end-systolic volumes (LVEDV, RVEDV, LVESV and RVESV) can be calculated from tomographic radionuclide ventriculography (TRV). The aim of this study was to validate and compare these parameters obtained using four different TRV software programs (QBS, QUBE, 4D-MSPECT and BP-SPECT). LVEF obtained from planar radionuclide ventriculography (PRV) was compared with LVEF obtained from TRV using the four different software programs in 166 patients. Furthermore, ventricular volumes obtained using TRV (QBS, QUBE and 4D-MSPECT) were compared with those obtained using BP-SPECT, the latter being the only method with the validation of ventricular volumes in the literature. The correlation of LVEF between PRV and TRV was good for all methods: 0.81 for QBS, 0.79 for QUBE, 0.71 for 4D-MSPECT and 0.79 for BP-SPECT. The mean differences+/-standard deviation (SD) were 3.16+/-9.88, 10.72+/-10.92, 3.43+/-11.79 and 2.91+/-10.39, respectively. The correlation of RVEF between BP-SPECT and QUBE and QBS was poor: 0.33 and 0.38, respectively. LV volumes calculated using QBS, QUBE and 4D-MSPECT correlated well with those obtained using BP-SPECT (0.98, 0.90 and 0.98, respectively), with mean differences+/-SD of 7.31+/-42.94, -22.09+/-36.07 and -40.55+/-39.36, respectively. RV volumes showed poorer correlation between QBS and BP-SPECT and between QUBE and BP-SPECT (0.82 and 0.57, respectively). LVEF calculated using TRV correlates well with that calculated using PRV, but is not interchangeable with the value obtained using PRV. Volume calculations (for left and right ventricle) and RVEF require further validation before they can be used in clinical practice.

Accuracy of commercially available processing algorithms for planar radionuclide ventriculography using data for a dynamic left ventricular phantom

Automatic and semi-automatic algorithms to calculate ejection fraction (EF) from planar radionuclide ventriculography (PRV) have been used for many years in nuclear medicine. Validation of these algorithms is scarce and often performed on outdated versions of the software. Nevertheless, clinical trials where PRV is being used as the 'gold standard' for EF are numerous. Because of the importance attributed to the EF calculated by these programs, the accuracy of the resulting EF was assessed with a dynamic left ventricular physical phantom. A dynamic left ventricular phantom was used to simulate 21 combinations of various ejection fractions (7-66%) and end diastolic volumes (27-290 ml). For each combination, a planar radionuclide ventriculograph was acquired, converted to an interfile format and transferred into processing stations with 10 different contemporaneously available commercial algorithms. The gold standard was the 'real' EF of the phantom, derived from the exact volume of the ventricle in end diastolic and end systolic position. Correlation and Bland-Altman analysis was performed between the real EF and the calculated EF. The correlation for all data was excellent (r=0.98), the mean difference was very acceptable (0.98%). Nevertheless, Bland-Altman analysis showed a significant trend in the difference between real and calculated EF, with a growing underestimation for higher ranges of EF, due to an overestimation of background in larger volumes compared to smaller ones. The determination of EF from PRV, calculated with commercially available algorithms, correlates closely to the real EF of a dynamic left ventricular phantom. This phantom can be used in the development and validation of algorithms for PRV studies, in software audits and in quality assurance procedures.

Comparison of myocardial gated single photon emission computerised tomography, planar radionuclide ventriculography and echocardiography in evaluating left ventricular ejection fraction, wall thickening and wall motion

Left ventricular ejection fraction (LVEF) and wall thickening are fundamental aspects of cardiac function. Recently, gated single photon emission computerised tomography (GSPECT) and anatomical M-mode echocardiography are new techniques, which have been introduced for the evaluation of left ventricular wall thickening and ejection fraction. These, however, have not been evaluated against established techniques, including equilibrium radionuclide ventriculography (ERNV), which remains the current gold standard for the evaluation of LVEF. We examined the concordance between LVEF, wall motion and wall thickening scores derived from GSPECT, echocardiography and ERNV, in a group of 16 patients with suspected ischaemic heart disease. Estimated ejection fraction correlated better between ERNV and gated SPECT (R2 = 0.93) than between echocardiography and either gated SPECT (R2 = 0.62) or ERNV (R2 = 0.71). There was poor correlation between gated SPECT and anatomical M-mode echocardiography in the assessment of wall thickening (83/150, 56%; kappa= 0.31, p < 0.05) and similar correlation (100/150, 66%; kappa = 0.29, p < 0.01) for wall motion analysis. In conclusion, estimations of ejection fraction by all the three studied modalities agreed to a degree sufficient for routine clinical practice. However, estimates of wall thickening from echocardiography cannot be used interchangeably with those derived from gated myocardial perfusion SPECT.

Comparison of myocardial gated spect, planar radionuclide ventriculography and echocardio-graphy in evaluating left ventricular ejection fraction, wall motion and thickening

Background: Left ventricular ejection fraction (LVEF) and wall thickening are fundamental aspects of cardiac function. Gated single photon emission computerised tomography (GSPECT) has been well validated against established techniques including MRI for the evaluation of left ventricular systolic function including wall motion and thickening. Recently, Anatomical m-mode echocardiography is a new technique, which has been introduced for the evaluation of left ventricular wall thickening and ejection fraction. This however have not been evaluated against established techniques, including equilibrium radionuclide ventriculography (ERNV), which remains the current gold standard for the evaluation of left ventricular ejection fraction. Methods: We examined the concordance between LVEF, wall motion and wall thickening scores derived from GSPECT, echocardiography, and ERNV in a group of 16 patients with suspected ischaemic heart disease (IHD). Results: Estimated ejection fraction correlated better between ERNV and gated SPECT (R 2=0.93) than between echocardiography and either gated SPECT (R 2 = 0.62) or ERNV (R 2= 0.71). There was poor correlation between gated SPECT and anatomical M-mode echocardiography in the assessment of wall thickening [83/150, 56%; kappa = 0.31, p < 0.05] and similar correlation [100/150, 66% Kappa = 0.29, p< 0.01] for wall motion analysis. Conclusion: Estimations of ejection fraction by all the three studied modalities agreed to a degree sufficient for routine clinical practice. However estimates of wall thickening from echocardiography cannot be used interchangeably with those derived from gated myocardial perfusion SPECT.

P5. A comparison of five processing methods for planar radionuclide ventriculography

s of the 30th Annual Meeting of the British Nuclear Medicine Society Manchester, UK, 8-10 April 2002. POSTER PRESENTATIONS

Automatic quantification of left ventricular ejection fraction from gated blood pool SPECT

Background. Cardiac gated blood pool single photon emission computed tomography (GBPS) better separates cardiac chambers compared with planar radionuclide ventriculography (PRNV). We have developed a completely automatic algorithm to measure quantitatively the left ventricular ejection fraction (LVEF) from gated technetium 99m-red blood cells (RBC) GBPS short-axis 3-dimensional image volumes. Methods and Results. The algorithm determines an ellipsoidal coordinate system for the left ventricle and then computes a static estimate of the endocardial surface by use of counts and count gradients. A dynamic surface representing the endocardium is computed for each interval of the cardiac cycle by use of additional information from the temporal Fourier transform of the image data sets. The algorithm then calculates the left ventricular volume for each interval and computes LVEF from the end-diastolic and end-systolic volumes. The algorithm was developed in a pilot group (N = 45) and validated in a second group (N = 89) of patients who underwent PRNV and 8-interval GBPS. Technically inadequate studies (N = 38) were rejected before grouping and processing. Automatic identification and contouring of the left ventricle was successful in 121 172 patients (70%) globally and in 76 89 patients (85%) in the validation group. Correlation between LVEFs measured from GBPS and PRNV was high (y = 2.00 + 1.01x, r = 0.89), with GBPS LVEF significantly higher than PRNV LVEF (average difference = 2.8%, P < .004). Conclusions. Our automatic algorithm agrees with conventional radionuclide measurements of LVEF and provides the basis for 3-dimensional analysis of wall motion.

Comparison between planar and tomographic radionuclide ventriculography for detecting inferior wall motion abnormalities

Gated planar radionuclide ventriculography is routinely used for the detection of regional wall motion abnormalities of the left ventricle. However, for inferior wall motion abnormalities, sensitivity is known to be low in the left anterior oblique 'best septal' projection, although improved if a left posterior oblique (LPO) view is also acquired. Gated tomography of the cardiac blood pool is now available. This study compared the sensitivity of planar 'best septal' projection, LPO and tomographic radionuclide ventriculography in the detection of inferior wall motion abnormalities. Thirty-two patients consisting of 18 with previous inferior myocardial infarction and 14 normal controls were studied. All patients underwent equilibrium planar 'best septal', planar LPO and then tomographic radionuclide ventriculography. Inferior wall motion abnormality was detected in 'best septal' in eight (44%) patients, LPO in 12 (67%) and tomography in 17 (94%) patients, respectively. Tomographic radionuclide ventriculography was best at detecting inferior wall motion abnormality while planar LPO projection is better than 'best septal' projection.

Non-invasive measurement of left ventricular volumes and function by gated positron emission tomography.

To date cardiac positron emission tomography (PET) studies have focussed on the measurement of myocardial blood flow, metabolism and receptors while left ventricular (LV) function and dimensions have been derived from other modalities. The main drawback of this approach is the difficulty of data co-registration, which limits clinical interpretation. The aim of this study was to evaluate whether it is possible to measure absolute cardiac volumes, and consequently LV function parameters such as ejection fraction, and wall motion with gated PET. Nineteen patients underwent a PET scan and planar radionuclide ventriculography (MUGA) within 9+/-9 days. A 9-min scan (16 gates/cardiac cycle) was acquired after inhalation of 3 MBq/ml of oxygen-15 labelled carbon monoxide at the rate of 500 ml/min over 4 min using a multislice PET camera. Noise reduction was performed on the gated image to enhance the definition of the ventricles before reslicing to the short-axis view. A threshold value was used to detect the edge of the LV at each gate. LV volumes at each gate were estimated by summing the volume of voxels within the LV boundary. PET measurements of LV volumes were as follows: LV end-diastolic volume ranged from 72 to 233 ml and LV end-systolic volume ranged from 24 to 203 ml. Phantom experiments supported the validity of this approach for estimating volumes. LV ejection fraction measured with MUGA was 38.4%+/-16.3% (range 15%-71%) and that measured with PET was 39.6%+/-17.7% (range 9%-72%) (P=NS). The LV ejection fraction measurements were highly correlated (r2=0.824). These results indicate that: (1) absolute end-diastolic and end-systolic volumes can be quantified using gated PET and (2) LV ejection fraction can be accurately measured by gated PET simultaneously with the other physiological PET parameters.

Evaluation of left ventricular volumes by planar and SPECT radionuclide ventriculography methods

Evaluation of left ventricular volumes by planar and SPECT radionuclide ventriculography methods