Equilibrium radionuclide angiography compared with tissue doppler imaging for detection of right ventricular dyssynchrony and prediction of acute response to cardiac resynchronization therapy.

OBJECTIVE: The aim of this study was to compare tissue doppler imaging (TDI) and equilibrium radionuclide angiography (ERNA) for detection of right ventricular (RV) dyssynchrony and prediction of the acute response to cardiac resynchronization therapy (CRT). METHODS: This study was approved by the local ethics committee of Huai'an First People's Hospital. Patient consent was not provided due to the use of completely anonymous images from which the individual could not be identified in this study. Thirty-three patients with nonischemic dilated cardiomyopathy underwent both TDI and ERNA before and within 48 hour after CRT implantation. RV dyssynchrony was measured with TDI using the difference in time to peak systolic velocity between the RV free wall and ventricular septum (RV-T). With ERNA, the standard of RV mean phase angle and RV phase standard deviation (RVmPA% and RVPSD%) were assessed. RESULTS: Moderate positive correlations were observed among baseline RVmPA%, RVPSD% and RV-T (r = 0.689 and 0.716, P < .001). Twenty patients (61%) with a reduction of at least 15% in LV end-systolic volume were categorized as acute responders after CRT. Responders showed significant reduction in RVmPA% and RVPSD% after CRT (53.60 ±â€Š4.15% to 43.95 ±â€Š6.88% and 14.00 ±â€Š2.41% to 10.40 ±â€Š1.67%, P < .05), whereas RV-T remained unchanged (50.10 ±â€Š10.28 ms to 49.25 ±â€Š13.64ms, NS). Receiver operating characteristic curve showed that the cut-off value of RV-T was 48.5ms, yielding 65% sensitivity and 77% specificity to predict acute respond to CRT. The cut-off value of RVmPA% was 49.5%, yielding 85% sensitivity and 85% specificity and the cut-off value of RVPSD% was 11.5%, yielding 85% sensitivity and 92% specificity. CONCLUSION: ERNA might be an appropriate alternative to TDI for assessment of RV dyssynchrony. Either RVmPA% or RVPSD% was highly predictive for acute response to CRT.

Application of the R0-R3 formulas using the ECToolbox software to calculate left ventricular ejection fraction in myocardial perfusion SPET and comparison with equilibrium radionuclide ventriculography. Normal cutoff values for a Chinese population.

The aim of this study was to compare the correlation and consistency of left ventricular ejection fraction (LVEF) obtained by ECG-gated myocardial perfusion SPET (GMPS) using the four formulas (R0-R3) in ECToolbox software and by equilibrium radionuclide ventriculography (ERNV), and determine the optimal diagnostic thresholds of the four formulas in a Chinese population. A hundred and three candidate donors (59 male and 44 female), including 38 patients with a history of myocardial infarction and 65 patients with suspected coronary heart disease, underwent both (99m)Tc-MIBI rest GMPS and technetium-99m red blood cells ((99m)Tc-RBC) ERNV within a week. The LVEF values calculated by ECToolbox R0, R1, R2 and R3 were compared with those obtained by ERNV. Using LVEF≥50% obtained by ERNV as the gold standard, the optimal diagnostic thresholds of the four formulas (R0-R3) were assessed by receiver operating characteristic (ROC) curves. Results showed that the mean LVEF value of ERNV was 54.6±17.5%, and the mean LVEF value of the four formulas was 64.1±15.7%, 56.3±15.1%, 69.9±17.9% and 56.3±13.6%, respectively, showing a significantly strong correlation between the results obtained by the two methods (r>0.85, P<0.001). All mean LVEF values obtained by the four formulas were higher than the mean LVEF value obtained by ERNV, and there was very significant difference between R0 and R2 results and the ERNV result (t=12.511 and 18.652, P<0.001). Furthermore, there was significant difference between R1 and R3 results and the ERNV result (t=2.169 and 2.570, P<0.05). Using ERNV LVEF≥50% as the normal diagnostic value, the optimal diagnostic threshold of R0∼R3 was 56.5%, 51.5%, 64.5% and 52.5%, respectively. There was a strong correlation between the LVEF values obtained by the four formulas in ECToolbox software and ERNV, but the numerical values of LVEF differed between the four formulas. In conclusion, A strong correlation was observed among R0, R1, R2 and R3 in the ECToolbox software when compared with ERNV and also between them for the assessment of LVEF. However, there were some differences in the numerical values of LVEF generated by the individual formulas, which must be taken into account in comparing clinical studies.

Reference range for intrapatient variability in blood-pool and liver SUV for 18F-FDG PET.

UNLABELLED: (18)F-FDG PET qualitative tumor response assessment or tumor-to-background ratios compare targets against blood-pool or liver activity; standardized uptake value (SUV) semiquantitation has artifacts and is validated by a stable normal-tissue baseline. The aim of this study was to document the normal intrapatient range of scan-to-scan variation in blood-pool SUV and liver SUV and to identify factors that may adversely affect it (increase its spread). METHODS: Between July 2009 and June 2010, 132 oncology patients had 2 PET/CT scans. Patient preparation, acquisition, and reconstruction protocols were held stable, uniform, and reproducible. Mean SUV (body weight) values were obtained from 2-dimensional regions of interest in the aortic arch blood pool and in the right lobe of the liver. RESULTS: Of the 132 patients, 65 had lymphoma. Their mean age was 62.5 y. The group's mean serum glucose level was 6.0 mmol/L at the first visit and 5.9 mmol/L at the second visit. The mean (18)F-FDG dose was 4.1 MBq/kg at the first visit and 4.0 at the second. At the first visit, the group's mean blood-pool SUV was 1.55 (SD, 0.38); at the second, 1.58 (SD, 0.37)-not statistically different. The group's mean liver SUV was 2.17 (SD, 0.44) at the first visit and 2.29 (SD, 0.44) at the second (P = 0.005). Visit-to-visit intrapatient variation in blood-pool and liver SUVs had gaussian distributions. The variation in blood-pool SUV had a mean of 0.03 and SD of 0.42. The variation in liver SUV had a mean of 0.12 and SD of 0.50. Using 95th percentiles, the reference range in our patient population for intrapatient variation was -0.8 to 0.9 for blood pool SUV and -0.9 to 1.1 for liver SUV. Subanalysis by cancer type and chemotherapy suggested that the rise in liver SUV between the 2 visits was largely due to the commencement of chemotherapy, but no factors were identified as systematically affecting intrapatient variation, and no factors were identified as increasing its spread. CONCLUSION: In our patient cohort, the reference range for intrapatient variation in blood-pool and liver SUVs is -0.8 to 0.9 and -0.9 to 1.1, respectively.

Evaluation of left and right ventricular ejection fraction and volumes from gated blood-pool SPECT in patients with dilated cardiomyopathy: comparison with cardiac MRI.

UNLABELLED: This prospective study evaluated the accuracy of electrocardiogram-gated blood-pool SPECT (GBPS) for the assessment of left ventricular (LV) and right ventricular (RV) ejection fraction (EF), end-diastolic volume (EDV), and end-systolic volume (ESV) in patients with dilated cardiomyopathy (DCM), using cardiac magnetic resonance (CMR) imaging as the reference standard. METHODS: Thirty-two patients (24 men and 8 women; mean age, 51 y) with a diagnosis of idiopathic DCM underwent GBPS and CMR. LV and RV parameters including EDV, ESV, and EF from GBPS were calculated using fully automated gradient software and compared with those obtained by CMR. RESULTS: Biventricular volumes were underestimated by GBPS, compared with CMR (P < 0.001). We found no statistical difference between these 2 methods in the assessment of LV EF (P = 0.23), whereas RV EF was overestimated by GBPS (P < 0.001 vs. CMR). Regression analysis yielded significant correlations between GBPS and CMR in the assessments of biventricular parameters (r = 0.83 for LV EDV, 0.88 for LV ESV, 0.89 for LV EF, 0.86 for RV EDV, 0.86 for RV ESV, and 0.62 for RV EF; all P < 0.001). Comparison of the deviations of RV indices between GBPS and CMR with the ratio of RV EDV to LV EDV showed that there was a statistically significant trend for RV volumes to be underestimated and for RV EF to be overestimated as the biventricular volumetric ratio decreased (r = 0.61 for RV EDV, 0.68 for RV ESV, and -0.55 for RV EF; all P < 0.001). CONCLUSION: For patients with DCM, GBPS correlated well with CMR for the assessment of biventricular parameters, but RV indices should be cautiously interpreted.

Automated detection of left ventricular dyskinesis by gated blood pool SPECT.

OBJECTIVE: The ability to detect left ventricular (LV) apical dyskinesis, the hallmark of an aneurysm, is an important requirement of diagnostic cardiac imaging modalities that perform wall motion analysis. Our investigation assessed the ability of gated blood pool single-photon emission-computed tomography (GBPS) to automatically detect LV dyskinesis, using cardiac magnetic resonance (CMR) as the reference standard. MATERIALS AND METHODS: GBPS data were analyzed for 41 patients with congestive heart failure or cardiomyopathy and compared with ECG-gated TrueFISP CMR evaluations. An experienced nuclear cardiologist without the knowledge of quantitative GBPS or CMR results graded visual impressions of regional wall motion while examining cinematic playbacks of GBPS images. GBPS algorithms automatically isolated LV counts and computed regional phase (phi) values in each of 17 conventional American Heart Association LV segments. LV asynchrony was quantified by the two local measures: maximum apical phi difference (Deltaalpha), and standard deviation among apical phases (sigmaalpha), and by the five global measures: varphi histogram bandwidth (BWHistogram), phi histogram standard deviation (sigmaHistogram), Z-scores, Entropy, and Synchrony. For CMR data, an expert manually drew endocardial LV outlines to measure regional wall motion in 17 LV segments. RESULTS: Apical dyskinesis was present in nine patients. Among GBPS measurements, the method with the greatest accuracy for detecting dyskinesis was Deltaalpha (receiver operating characteristic area=95%). The only method with a sufficiently high kappa statistic to represent 'very good agreement' with CMR was Deltaalpha, with kappa=0.81. Deltaalpha was more sensitive in detecting dyskinesis than visual analysis (100 vs. 33%, P=0.01). CONCLUSION: Automatic GBPS computations accurately identified patients with LV dyskinesis, and detected dyskinesis more successfully than did visual analysis.

Evaluation of ventricular synchrony with equilibrium radionuclide angiography: assessment of variability and accuracy.

BACKGROUND AND AIMS: Equilibrium radionuclide angiography (ERNA) has become an established method for assessing cardiac function. However, limited data are available to evaluate ventricular synchrony with ERNA. The aim of this study was to assess the variability and accuracy of ERNA to evaluate ventricular synchrony by means of phase images in healthy individuals and to compare them with a group of subjects with left bundle-branch block (interventricular dyssynchrony, LBBB) and with a group of patients with nonischemic, dilated cardiomyopathy (DCM) (inter- and intraventricular dyssynchrony). METHODS: The population was divided into groups as follows: group 1 included 22 healthy subjects, group 2 included 11 patients with LBBB and normal left ventricular ejection fraction (LVEF), and group 3 included 14 DCM patients with LVEF <35% and LBBB. Interventricular synchrony was measured as the difference between LV mean phase angle (mPA) and RV mPA (LV-RV mPA). Intraventricular synchrony for each ventricle was measured as the standard deviation (SD) of the RV mPA and LA mPA blood pools. RESULTS: Intra- and interobserver correlation coefficients were high for both inter- and intraventricular synchrony parameters. Area under the curve (AUC) was 0.98 for LV-RV mPA (p <0.001; 95% CI: 0.947-1.0). A cutoff value of 10 degrees yielded 96% sensitivity and 99% specificity to identify interventricular dyssynchrony. AUC was high for SD RV mPA and SD LV mPA (AUC = 1.0, p <0.001; 95% CI: 1.0-1.0 and AUC = 0.99, p <0.001; 95% CI: 0.979-1.0). A cutoff value of 22 degrees for SD LV mPA yielded 100% sensitivity and 100% specificity to identify LV intraventricular dyssynchrony. A cutoff value of 20 degrees for SD RV mPA yielded 100% sensitivity and 99% specificity to identify RV intraventricular dyssynchrony. CONCLUSIONS: ERNA is an accurate and highly reproducible technique for evaluation of ventricular function and synchrony.

Creation and characterization of Japanese standards for myocardial perfusion SPECT: database from the Japanese Society of Nuclear Medicine Working Group.

OBJECTIVE: Standards for myocardial single-photon emission computed tomography (SPECT) adapted for a Japanese population were not available. The purpose of this study was to create standard files approved by the Japanese Society of Nuclear Medicine and to make known the characteristics of the myocardial perfusion pattern of this population. METHODS: With the collaboration of nine hospitals, a total of 326 sets of exercise-rest myocardial perfusion images were accumulated from subjects with a low likelihood of cardiac diseases. The normal database included a (99m)Tc-MIBI/tetrofosmin myocardial perfusion study with 360 degrees (n = 80) and 180 degrees (n = 56) rotations, (201)Tl study with 360 degrees (n = 115) and 180 degrees rotations (n = 54) and a dual-isotope study with 360 degrees rotation (n = 27). The projection images were transferred by digital imaging and communications in medicine (DICOM) format and reconstructed and analyzed with polar maps. RESULTS: The projection data from multiple centers were successfully transferred to a common format for SPECT reconstruction. When the average values were analyzed using a 17-segment model, myocardial counts in the septal segment differed significantly between 180 degrees and 360 degrees rotation acquisitions. Regional differences were observed between men and women in the inferior and anterior regions. A tracer difference between (99m)Tc and (201)Tl was also observed in some segments. The attenuation patterns differed significantly between subjects from the United States and those from Japan. CONCLUSIONS: Myocardial perfusion data that were specific for the Japanese population were generated. The normal database can serve a standard for nuclear cardiology work conducted in Japan.

Normal limits of ejection fraction and volumes determined by gated SPECT in clinically normal patients without cardiac events: a study based on the J-ACCESS database.

PURPOSE: Quantitative gated single-photon emission computed tomography (SPECT) is known to have high accuracy and precision for measurement of the principal cardiac functional parameters. We hypothesised that normal values for EF and LV volumes may differ among nationalities, and that optimal threshold values specific to the study population are required. METHODS: Among 4,670 consecutively registered patients for a J-ACCESS (Japanese investigation regarding prognosis based on gated SPECT) study from 117 hospitals, a total of 268 (149 women, 119 men) were selected who had no baseline cardiac diseases and had experienced no cardiac events during the preceding 3-year period. A gated SPECT study was performed with 99mTc-tetrofosmin and analysed with Cedars Sinai Medical Center's quantitative gated SPECT (QGS) software. The results in respect of ejection fraction (EF), end-diastolic volume (EDV), end-systolic volume (ESV) and stroke volume (SV), and EDV, ESV and SV normalised by body surface area (EDVI, ESVI and SVI), were calculated and summarised to obtain normal limits. RESULTS: EF for women and men was 74 +/- 9% and 63 +/- 7%, respectively (p < 0.0001). EDV, ESV and SV were significantly smaller in women than in men. Based on multiple regressions for linear models, the primary and secondary predictors of EF, EDVI, ESVI were gender and age. By stepwise multiple regression analysis, a statistically significant third predictor for EDV, ESV, SV and SVI was body weight. No colinearity was found between age and body weight. Important factors for the studied Japanese population included a high incidence of small hearts in women and the relatively advanced age of the population (the mean age +/-SD was 64.1 +/- 10.0 years for women and 60.9 +/- 11.7 years for men). CONCLUSION: EF and volumes determined by gated SPECT with QGS were significantly affected by gender and age, with body weight as a third predictor for volumes. Moreover, the normal limits were so specific for the population studied that standards appropriate for the study in question should be utilised.

Onset of left ventricular mechanical contraction as determined by phase analysis of ECG-gated myocardial perfusion SPECT imaging: development of a diagnostic tool for assessment of cardiac mechanical dyssynchrony.

BACKGROUND: A count-based method using technetium-99m sestamibi electrocardiography-gated myocardial perfusion single photon emission computed tomography imaging has been developed to extract the left ventricular (LV) regional phase of contraction (onset of mechanical contraction [OMC]) throughout the cardiac cycle. This study was performed to develop OMC normal databases and dynamic OMC displays for assessment of cardiac mechanic dyssynchrony. METHODS AND RESULTS: LV regional phases were extracted from 90 enrolled normal subjects (45 men and 45 women) by use of the Emory Cardiac Toolbox and then submitted to statistical analysis to generate the normal databases. The LV OMC wave was dynamically propagated over the perfusion polar map by blackening either sequential phase bins or all past phases. The developed OMC normal databases consisted of peak phase (134.5 degrees +/- 14.3 degrees for men and 140.2 degrees +/- 14.9 degrees for women), phase SD (14.2 degrees +/- 5.1 degrees for men and 11.8 degrees +/- 5.2 degrees for women), and phase histogram bandwidth (38.7 degrees +/- 11.8 degrees for men and 30.6 degrees +/- 9.6 degrees for women), skewness (4.19 +/- 0.68 for men and 4.60 +/- 0.72 for women), and kurtosis (19.72 +/- 7.68 for men and 23.21 +/- 8.16 for women). Both statistical analysis and dynamic OMC displays were incorporated into a user interface as a diagnostic tool. CONCLUSION: The OMC normal databases and dynamic OMC displays should help clinicians evaluate cardiac mechanic dyssynchrony. Prospective clinical trials are needed to validate whether this tool can be used to select patients with severe heart failure symptoms who might benefit from cardiac resynchronization therapy.

UK audit of left ventricular ejection fraction estimation from equilibrium ECG gated blood pool images.

PURPOSE: To examine the variability of results obtained from computer analysis of left ventricular gated blood pool (LVGBP) images by nuclear medicine centres in the UK. METHODS: Twelve data sets of LVGBP images were distributed via commercial software suppliers to nuclear medicine centres in the UK. Two of the data sets were duplicates and three were acquired from the same patient with different total counts in the images. The quality of the images was also variable and two images had poorly defined left ventricular walls. A questionnaire was used to identify the parameters used during the analysis and to give an indication of the number of LVGBP scans per year routinely carried out by each centre as well as report the results obtained from the analysis. RESULTS: Results were received from 63 nuclear medicine centres using 77 computer systems. The vast majority of participants (57) carried out fewer than 10 scans per month. Only two centres performed more than 30 scans per month. Sixteen centres did not quote a minimum normal value for left ventricular ejection fraction (LVEF) and 36 did not record a maximum value. The remainder recorded between 0.40 and 0.60 for the minimum of normal range and 0.60-0.90 for the maximum of normal range. Analysis of returns showed that LVEF estimates for the data sets were highly variable between centres and computer systems. The overall standard deviation of results compared to the mean for each study was 0.076. Approximately half this variation was due to systematic variation between centres. The overall precision taking into consideration this systematic variation, was 0.055. Lower variability was found between studies with higher overall counts and this was highly significant.

A realistic 3-D gated cardiac phantom for quality control of gated myocardial perfusion SPET: the Amsterdam gated (AGATE) cardiac phantom.

A realistic 3-D gated cardiac phantom with known left ventricular (LV) volumes and ejection fractions (EFs) was produced to evaluate quantitative measurements obtained from gated myocardial single-photon emission tomography (SPET). The 3-D gated cardiac phantom was designed and constructed to fit into the Data Spectrum anthropomorphic torso phantom. Flexible silicone membranes form the inner and outer walls of the simulated left ventricle. Simulated LV volumes can be varied within the range 45-200 ml. The LV volume curve has a smooth and realistic clinical shape that is produced by a specially shaped cam connected to a piston. A fixed 70-ml stroke volume is applied for EF measurements. An ECG signal is produced at maximum LV filling by a controller unit connected to the pump. This gated cardiac phantom will be referred to as the Amsterdam 3-D gated cardiac phantom, or, in short, the AGATE cardiac phantom. SPET data were acquired with a triple-head SPET system. Data were reconstructed using filtered back-projection following pre-filtering and further processed with the Quantitative Gated SPECT (QGS) software to determine LV volume and EF values. Ungated studies were performed to measure LV volumes ranging from 45 ml to 200 ml. The QGS-determined LV volumes were systematically underestimated. For different LV combinations, the stroke volumes measured were consistent at 60-61 ml for 8-frame studies and 63-65 ml for 16-frame studies. QGS-determined EF values were slightly overestimated between 1.25% EF units for 8-frame studies and 3.25% EF units for 16-frame studies. In conclusion, the AGATE cardiac phantom offers possibilities for quality control, testing and validation of the whole gated cardiac SPET sequence, and testing of different acquisition and processing parameters and software.

Comparison of equilibrium radionuclide ventriculography with cardiovascular magnetic resonance for assessing the systemic right ventricle after Mustard or Senning procedures for complete transposition of the great arteries.

We assessed the utility of equilibrium radionuclide ventriculography for assessing function of the systemic right ventricle by comparing it with cardiovascular magnetic resonance (CMR) in subjects who had undergone the Mustard or Senning operations for complete transposition of the great arteries. The 95% limits of agreement for right ventricular ejection fraction by the 2 techniques were 15.8% to -16.0%, demonstrating that equilibrium radionuclide ventriculography has good agreement with CMR and provides a good alternative in cases in which CMR is not available or appropriate.