Automatic quantification of left ventricular ejection fraction from gated blood pool SPECT
ABSTRACT 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 patients (70%) globally and in 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.
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ABSTRACT: The technique of SPECT-RNV (radionuclide ventriculography) offers a greater amount of clinically usable data than its planar counterpart (P-RNV). In transitioning from planar to SPECT-only acquisition methodologies, reprojection of the SPECT data can provide a planar dataset which can be used as an interim technique. The aim of this study was to test if reprojected planar images could be used as a surrogate for true planar images in SPECT-only setting.Journal of Nuclear Cardiology 08/2014; · 2.85 Impact Factor
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ABSTRACT: Analysis using cardiac iodine-123 metaiodobenzylguanidine (MIBG) scintigraphy with regions of interest (ROIs) is useful for assessing myocardial sympathetic activity. However, manual placement of the cardiac ROI is sometimes difficult because myocardial MIBG uptake is reduced in patients with heart failure. A new method was developed to reconstruct the semiautomated cardiac ROI in a sympathetic denervated heart. Using dynamic planar data, a summed image was generated and the matrix size was changed. Then, the radial count profiles originating from the center of the left ventricle were generated to extract the myocardial count profiles. An asymmetric Gaussian distribution was fitted to each profile and the epicardial border was defined by the threshold method. This program was tested in 50 patients, and its reproducibility was validated when compared with the manual tracing method. The semiautomated method yielded a better quality image compared with the standard image with higher counts. Cardiac ROIs were generated successfully in each patient within normal limits. The intraobserver and interobserver agreements were excellent (P<0.0001 each). This approach showed a significantly higher consistency in measuring the heart-to-mediastinum ratio as compared with the manual tracing method (P<0.05). The semiautomated method is useful in generating cardiac ROIs with high reproducibility in myocardial MIBG imaging.Nuclear Medicine Communications 04/2014; · 1.38 Impact Factor
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ABSTRACT: Background The evaluation of the Right ventricle (RV) is a challenge; as a result six transthoracic echocardiography (TTE) parameters have been suggested. While gated blood-pool single photon electron computed tomography (GBPS) is a promising technique, there is currently no completely automated and validated processing software available clinically. Consequently, cardiac magnetic resonance (CMR) imaging remains the gold standard for RV assessment. We aimed to compare RV evaluation by GBPS and TTE to CMR. Methods 58 patients underwent CMR, GBPS and TTE for RV assessment, including volumes, RVEF and TTE’s indices of RV function (fractional area change (FAC), RV myocardial performance index by pulsed wave Doppler (MPI-PWD) and tissue Doppler (MPI-TDI) and tricuspid annular plane systolic excursion (TAPSE) by M-Mode and tissue Doppler (TAPSE-TDI)). GBPS was performed using both a commercial (QBS) and the Montreal Heart Institute (MHI) proprietary softwares. Results Nuclear medicine derived volumes quantification showed very good correlations with CMR, for RV end-diastolic (r = 0.84 and 0.77, all p < 0.001) and end-systolic (r = 0.82 and 0.67, all p < 0.001) volumes by MHI and QBS softwares respectively. RVEF showed a significant correlation with CMR in patients with RVEF ≤ 45% (r = 0.54, p = 0.029 and r = 0.55, p = 0.028, by MHI and QBS respectively). Amongst TTE parameters, only FAC and MPI-TDI were significantly correlated with CMR-RVEF, mainly for RVEF ≤ 45% (r = 0.63, p = 0.011 and r = 0.58, p = 0.046). Conclusions GBPS, both with MHI and QBS softwares, exhibited significant correlations with CMR for evaluation of the RV (volumes and decreased RVEF estimation). Amongst TTE’s parameters, only FAC and MPI-TDI showed significant correlation with CMR with RVEF ≤ 45%.International journal of cardiology 01/2013; · 6.18 Impact Factor