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Abstract: Factorial phase analysis (FaPI) represents an alternative method to Fourier phase analysis (FoPI) in the evaluation and detection of abnormalities on cardiac contraction patterns, but it has limitations in representing the sequence in abnormal contraction patterns. In this work we propose a modified factorial phase image (FaPIm) that incorporates more complete information regarding the ventricular contraction sequence. In particular, we analyze and evaluate the contribution of the third eigenimage, in the presence of ventricular dyssynchrony, which has not been sufficiently explored in the literature. We have validated the proposed FaPIm using two Equilibrium Radionuclide Angiography (ERNA) sets of images obtained with a dynamic cardiac phantom and with a numerically simulated phantom. Also, we have tested the proposed representation for a control group of 23 normal subjects and for a sample of 15 patients with Complete Left Bundle Branch Block (LBBB). Whereas FoPI allows us to obtain an image that synthesizes ventricular contraction with the smallest dispersion around the mean values, FaPI and FaPIm show that external areas surrounding ventricular cavities present more dephasing than the rest of the ventricular region and contain more detailed information about the progression of contraction. Also, in the presence of an abnormal contraction pattern, the magnitude of the third eigenvalue was greater than the corresponding eigenvalue obtained for normal simulations. The dispersion plots obtained for a normal contraction pattern show that left ventricle (LV) and right ventricle (RV) information overlap. Therefore, when there is a dyssynchrony between LV and RV contraction it becomes necessary to incorporate the information corresponding to the third factor to achieve a clear separation between regions. In the comparison of the indices of control and LBBB populations, FaPIm shows significant differences in five out of six contraction indices, showing its promising value as a clinical tool. [Copyright &y& Elsevier]

Background: Cardiovascular disease is a major cause of morbidity and mortality in end-stage renal disease (ESRD). Renal transplant is known to improve left ventricle hypertrophy and systolic dysfunction in selected groups of patients. Methods: We assessed myocardial perfusion, wall motion and functional parameters by single photon emission computed tomography (SPECT) and Gated-SPECT in 30 consecutive ESRD patients with normal coronary angiograms before and after renal transplantation. Results: Uremic cardiomyopathy improved significantly after the transplant. The proportion of patients with angina decreased from 26 to 0%; the frequency of cardiomegaly decreased from 57 to 20% (p <0.01); the frequency of segments with perfusion defects decreased from 42.7 to 10.2% (p <0.001); the proportion of patients with low left ventricular ejection fraction (LVEF) dropped from 53.3 to 20% (p <0.001); and mean LVEF increased from (48.0 ± 9.7% to 58.2 ± 8.2%). Similarly, the proportion of segments showing systolic wall thickening, hypokinesia and dyskinesia also decreased significantly after renal transplant (p <0.01). Conclusions: Uremic cardiomyopathy may be potentially reversible in patients with normal angiographic coronary arteries after renal transplant in a relatively short period of time. SPECT and Gated-SPECT are objective gateway methods to determine myocardial perfusion, hypokinesia, dyskinesia, and functional parameters (left ventricular ejection fraction and systolic wall thickening) and may be useful to establish diagnostic, coronariographic, prognostic, and therapeutic indications. [Copyright &y& Elsevier]

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° 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° for SD LV mPA yielded 100% sensitivity and 100% specificity to identify LV intraventricular dyssynchrony. A cutoff value of 20° 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. [Copyright &y& Elsevier]

Background: Previous studies demonstrated that 99mTc-labeled-ubiquicidin 29–41 (99mTc-UBI 29–41) imaging is an accurate method for detection of bacterial infections. This study was conducted to evaluate the clinical use of 99mTc-UBI 29–41 for detection of mediastinitis after cardiac surgery. Methods: Thirteen patients with suspected mediastinitis after cardiac surgery were included. Qualitative and semiquantitative analyses of 99mTc-UBI 29–41 images were performed. Mediastinitis was confirmed by bacterial culture. Results: Qualitative analysis correctly identified the infection in 5/6 patients with mediastinitis. For observer 1, there were five true-positive results, six true-negative results, one false-positive result and one false-negative result (sensitivity: 83%, specificity: 85%, positive predictive value: 83%, negative predictive value: 85%, and overall diagnostic accuracy: 84%). For observer 2, there were five true-positive results, five true-negative results, two false-positive results and one false-negative result (sensitivity: 83%, specificity: 71%, positive predictive value: 71%, negative predictive value: 83%, and overall diagnostic accuracy: 76%). Agreement between observers was 0.847 (SE=0.145, p =0.002). Semiquantitative analysis showed a higher mediastinum uptake of the 99mTc-UBI 29–41 in patients with mediastinitis than that derived from patients without mediastinitis. Mean uptake of 99mTc-UBI 29–41 was 60.4±10.3 counts/pixel and 47.4±5.5 counts/pixel, respectively (p =0.01). At the threshold value of ≥57 counts/pixel using ROC analysis, the sensitivity, specificity, positive predictive value, negative predictive value and overall diagnostic accuracy for detecting patients with mediastinitis were 83, 100, 100, 87, and 92%, respectively (p =0.02; 95% CI: 0.65–1.10%). Conclusions: 99mTc-UBI 29–41 imaging yielded fast and promising first results for patients with suspected mediastinitis after cardiac surgery and, as such, deserves further investigation. [Copyright &y& Elsevier]