Quantitative Gated SPECT Research Articles

Sixteen-Frame Gated Myocardial Perfusion SPECT as a Surrogate for Equilibrium Radionuclide Angiography in Measurement of Systolic and Diastolic Indices: A Cross-Sectional Study

Abstract Introduction Equilibrium radionuclide angiography (ERNA) has long been assumed as the preferred method to assess cardiac volumes as well as left ventricular systolic and diastolic indices. ERNA was used to diagnose subtle changes in cardiac function during chemotherapy or early stages of heart failure. Gated myocardial perfusion SPECT (GMPS) was introduced as a more feasible and versatile alternative to ERNA, but the precision of GMPS to assess systolic and diastolic indices has not yet been fully reviewed. Method We studied the left ventricular systolic and diastolic functional indices measured by a 16-frame GMPS and compared the results with those of ERNA in 25 patients. All the images were analyzed visually, semi-quantitatively, and quantitatively using quantitative gated SPECT (QGS), quantitative blood pool SPECT (QBS), and planar gated blood pool (PGBP) software. The left ventricular functional indices calculated using QGS compared with those obtained using QBS and PGBP Result Our study found a significant correlation between the left ventricular ejection fraction (LVEF) calculated using the PGBP, QGS, and QBS methods. There was a significant correlation between the LV peak ejection rate (LVPER) calculated by the PGBP and QGS analyses, and there was no significant difference in the LVPER calculated with the QGS and QBS methods. This study also revealed a significant correlation between the LV peak filling rate (LVPFR) calculated by QBS and QGS, with no significant difference between them. We also found a significant correlation between LV end systolic volume (LVESV) calculated using QGS and QBS and between LV end diastolic volume (LVEDV) calculated using QGS and QBS software. This study also revealed a significant correlation between the LV mean filling rate over the first third of diastole (LVMFR/3) calculated using the QGS and QBS software. Conclusion Considering the significant correlation between LVEF, LVPER, LVPFR, LVESV, LVMFR/3, and LVEDV calculated using the QGS and QBS methods in our study, the 16-frame GMPS could be regarded as an acceptable substitute for ERNA in the investigation of systolic and diastolic indices.

CMR validation of left ventricular volumes and ejection fraction measured by the IQ-SPECT system in patients with small heart size

BackgroundThe IQ-SPECT system is equipped with multifocal collimators and uses ordered-subset conjugate gradient minimization (OSCGM) as its reconstruction algorithm, achieving a shorter acquisition time than conventional SPECT. Left ventricular ejection fraction (LVEF) is overestimated by conventional SPECT in patients with small heart size. In this study, we compared IQ-SPECT with conventional SPECT and cardiovascular magnetic resonance (CMR) for the estimation of LVEF in patients with small hearts (males: EDV ≤ 60 ml, ESV ≤ 25 ml; females: EDV ≤ 45 ml, ESV ≤ 20 ml).MethodsThe study consisted of 49 consecutive patients (20 normal and 29 with small heart size) undergoing gated myocardial perfusion imaging (GMPI) with a 99mTc-labelled agent during stress or rest to assess the risk of coronary artery disease (CAD). The data were reconstructed using filtered back-projection (FBP) for conventional SPECT and OSCGM for IQ-SPECT. ESV, EDV, and LVEF were calculated using quantitative gated SPECT (QGS). To determine the optimal ordered-subset reconstruction parameters, we compared the LVEF from SPECT to the corresponding measurement from CMR.ResultsEDV, ESV, and LVEF values obtained from IQ-SPECT and conventional SPECT showed that the results of these two forms of SPECT were significantly correlated, although the EDV and ESV obtained by IQ-SPECT were higher than those obtained by conventional SPECT. IQ-SPECT yielded lower LVEF measurements than conventional SPECT (normal heart size: 50.6 ± 4.3% vs. 73.4 ± 8.4%, P = 0.002; small heart size: 62.1 ± 7.8% vs. 75.0 ± 11.4%, P < 0.001). There were no significant differences in LVEF measurements made by IQ-SPECT and CMR (normal heart size: 50.6 ± 4.3% vs. 53.2 ± 5.8%, P > 0.05; small heart size: 62.1 ± 7.8% vs. 64.6 ± 8.8%, P > 0.05). Five subsets (S) and 12 iterations (I) did not differ significantly in LVEF between CMR and IQ-SPECT for patients with small hearts (64.6 ± 8.8% vs. 62.1 ± 7.8%, P = 0.120), while 3 S and 10 I were the best parameters for patients with normal heart size (50.6 ± 4.3% vs. 53.1 ± 5.8%, P = 0.117).ConclusionWith CMR as the standard, IQ-SPECT yields more reliable LVEF values than conventional SPECT for populations with small heart size. The best reconstruction parameters from IQ-SPECT were 5 S and 12 I for patients with small hearts.

The Relationship Between Coronary Slow Flow and Myocardial Ischaemia Evaluated with Timi Frame Count and Myocardial Perfusion Scintigraphy

Objective: Coronary slow flow (CSF) is known as a form or early stage of common atherosclerotic disease. Myocardial perfusion scintigraphy (MPS) is a valuable technique in the diagnosis of coronary artery disease and prediction of prognosis. The aim of this study was to investigate the relationship between the myocardial defect score and ischaemia in patients with CSF. Methods: A total of 168 patients who applied with the complaint of angina pectoris and underwent SPECT as a non-invasive test followed by coronary angiography were included in this retrospective study. 9 patient was excluded from the study for various reasons. The study population comprised determined with CSF and no obstructive stricture in the coronary arteries and with normal flow. The mean age of the patients was 56±12 years. The scores obtained from Quantitative Perfusion SPECT (QPS) and Quantitative Gated SPECT (QGS) software were used in the myocardial perfusion evaluation. The TIMI frame counts were compared with the myocardial defect and ischaemia scores. The TIMI frame count method was used in the determination of CSF. Results: In patients with slow flow in the circumflex (Cx) coronary artery, the stress total perfusion defect Cx (sTPD-Cx) was found to be 0.1 (range, 0.0-1.3), and in those with normal flow, it was 0.0 (range, 0.0-0.28) (p=0.002). The stress score Cx (sscore-Cx) was found to be 1.0 (range, 0.0-3.0) in patients with slow flow and 0.0 (range, 0.0-2.0) in those with normal flow (p=0.031). A linear correlation was determined between the Cx TIMI frame count and the sTPD-Cx and sscore-Cx values (r=0.207, p=0.009; r=0.159, p=0.045). No relationship was found between slow flow and the defect and ischemia scores in other myocardial regions. Conclusion: In patients with slow flow in the Cx coronary artery, the sTPD-Cx and the sscore-Cx values were found to be significantly high. Although at a weak level, a linear correlation was found between the Cx TIMI frame count and the sTPD-Cx and the sscore-Cx values

Sex-specific reference limits of left ventricular ejection fraction and volumes estimated by gated myocardial perfusion imaging for low-risk patients in China: a comparison between three quantitative algorithms.

Establishing appropriate reference value limits of left ventricular (LV) functional parameters is fundamental for the assessment of cardiac function. At present, there are no reports aimed at establishing reference limits using gated myocardial perfusion imaging (MPI) in mainland China. A total of 175 consecutive patients who were defined as low-risk coronary artery disease patients underwent stress Technetium-99m sestamibi (99mTc-MIBI)-gated myocardial perfusion single-photon emission computed tomography (SPECT) imaging. The LV ejection fraction (EF), end-diastolic volume (EDV), and end-systolic volume (ESV) were obtained by 3 quantitative algorithms: quantitative-gated SPECT, emory cardiac toolbox, and 4-dimensional model SPECT, respectively. The threshold values were obtained using Gaussian distribution or percentiles. The influence of gender, age, and weight on cardiac functional parameters was analyzed by multiple regressions for linear models. For males, the lower reference limits of EF were 52%, 63%, and 58%, respectively; and the upper limits of EDV/ESV were 106/45, 152/55, and 135/55 mL, respectively. For females, the lower reference limits of EF were 58%, 66%, and 65%, respectively; and the upper limits of EDV/ESV were 73/27, 105/31, and 88/29 mL, respectively. Compared to females, males had greater cardiac volume values and lower mean EF values. Bland-Altman plots revealed that the cardiac function parameters calculated by the three quantitative algorithms were in high agreement. In this study, the reference limits of cardiac parameters calculated by the 3 methods based on single-center data in China were preliminarily established. The threshold values determined by three quantitative algorithms were not interchangeable but were highly correlated.

Test–retest repeatability and software reproducibility of myocardial flow measurements using rest/adenosine stress Rubidium-82 PET/CT with and without motion correction in healthy young volunteers

BackgroundMyocardial flow reserve (MFR) assessment with cardiac positron emission computed tomography (PET/CT) is well established, and quantification relies on commercial software packages. However, for reliable use, repeatability and reproducibility are important. The aim of this study was therefore to investigate and compare between scans and software packages the repeatability and reproducibility of 82Rb-PET/CT estimated MFR. Methods and ResultsForty healthy volunteers completed two 82Rb-PET/CT rest and adenosine stress scans. syngo.MBF (Siemens), quantitative-gated SPECT (QGS) (Cedars-Sinai), and Corridor4DM (4DM) were used for analyses. Motion correction was available for 4DM. Fifty percent were men and age was 24 ± 4 years (mean ± SD). Repeatability of MFR varied between scans. syngo.MBF: mean difference (95% CI) 0.26 (− 0.03 to 0.54), P = 0.07, limits of agreement (LoA): − 1.43 to 1.95; QGS: 0.19 (− 0.08 to 0.46), P = 0.15, LoA: − 1.38 to 1.76; 4DM: 0.08 (− 0.17 to 0.34), P = 0.50, LoA: − 1.37 to 1.53; and 4DM motion corrected: 0.17 (− 0.17 to 0.51), P = 0.32, LoA: − 1.89 to 2.22. MFR was higher using 4DM +/− motion correction compared with syngo.MBF and QGS (all P < 0.0001). Concordance between syngo.MBF and QGS was high (P = 0.83). ConclusionsReproducibility of MFR varied for the different software. The highest concordance between MFRs was found between syngo.MBF and QGS.

Comparing left ventricular mechanical dyssynchrony between diabetic and non-diabetic patients with normal gated SPECT MPI

The aim of this study was to employ phase analysis to diagnose left ventricular mechanical dyssynchrony (LVMD) in asymptomatic patients with diabetes mellitus type 2 and normal perfusion study which may help prevent diabetic cardiomyopathy. Ninety-three consecutive patients with known type 2 diabetes and 81 age- and gender- matched patients without diabetes who were candidates for SPECT-MPI were considered as the control group. The presence of LVMD as an possible risk factor for cardiomyopathy- was determined using phase analysis for each scan with quantitative gated SPECT (QGS) and corridor4DM (4DM) software. All outcomes such as phase bandwidth (PBW) and phase standard deviation (PSD) were compared between the two groups. A total of 174 patients were included in the study. There were no statistically significant difference regarding demographic factors between the two groups (P > 0.05). PBW showed statistically significant differences (increased in diabetics) between the control and diabetic patients (P < 0.05). Kruskal Wallis analysis revealed that as the duration of diabetes is prolonged, especially more than 15years, the probability of LVMD is increased as well (P = 0.021). Fraction of asymptomatic diabetic patients with normal ejection fraction and gated SPECT MPI-especially those with prolonged diabetes- might have some degrees of LVMD. Phase analysis can detect this which in turn may prevent progress into heart failure.

Feasibility of simultaneous 99mTc-tetrofosmin and 123I-BMIPP dual-tracer imaging with cadmium-zinc-telluride detectors in patients undergoing primary coronary intervention for acute myocardial infarction

BackgroundSimultaneous dual-tracer imaging using isotopes with close photo-peaks may benefit from improved properties of cadmium-zinc-telluride (CZT)-based scanners. MethodsThirty patients having undergone primary percutaneous coronary intervention for acute myocardial infarction underwent single-(99mTc-tetrofosmin (TF) or 123I-BMIPP first) followed by simultaneous 99mTc-TF /123I-BMIPP dual-tracer imaging using a Discovery NM/CT 670 CZT. The values for the quantitative gated-SPECT (QGS) and the quantitative perfusion SPECT (QPS) were assessed. ResultsThe intra-class correlation (ICC) coefficients between the single- and dual-tracer imaging were high in all the QGS and QPS data (Summed motion score: 0.95, summed thickening score: 0.94, ejection fraction: 0.98, SRS for 99mTc-TF: 0.97/ for 123I-BMIPP: 0.95). Wall motion, wall thickening and rest scores per coronary-territory-based regions were also comparable between the single- and dual imaging (ICC coefficient > 0.91). The interrater concordance in the visual analysis for the infarction and perfusion-metabolism mismatch was significant for the global and regional left ventricle (P < 0.001). ConclusionThe quantitative/semi-quantitative values for global and regional left-ventricular function, perfusion, and fatty acid metabolism were closely comparable between the dual-tracer imaging and the single-tracer mode. These data suggests the feasibility of the novel CZT-based scanner for the simultaneous 99mTc-TF /123I-BMIPP dual-tracer acquisitions in clinical settings.

Effect of data conserving respiratory motion compensation on left ventricular functional parameters assessed in gated myocardial perfusion SPECT

BackgroundRespiratory motion compromises image quality in myocardial perfusion (MP) single-photon emission computed tomography (SPECT) imaging and may affect analysis of left ventricular (LV) functional parameters, including phase analysis-quantified mechanical dyssynchrony parameters. In this paper, we investigate the performance of two algorithms, respiratory blur modeling (RBM) and joint motion-compensated (JMC) ordered-subsets expectation maximization (OSEM), and the effects of motion compensation on cardiac-gated MP-SPECT studies.MethodsImage acquisitions were carried out with a dual-detector SPECT/CT system in list-mode format. A cardiac phantom was imaged as stationary and under respiratory motion. The images were reconstructed with OSEM, RBM-OSEM, and JMC-OSEM algorithms, and compared in terms of mean squared error (MSE). Subsequently, MP-SPECT data of 19 patients were binned into dual-gated (respiratory and cardiac gating) projection images. The images of the patients were analyzed with Quantitative Gated SPECT (QGS) 2012 program (Cedars-Sinai Medical Center, USA). The parameters of interest were LV volumes, ejection fraction, wall motion, wall thickening, phase analysis, and perfusion parameters.ResultsIn phantom experiment, compared to the stationary OSEM reconstruction, the MSE values for OSEM, RBM-OSEM, and JMC-OSEM were 8.5406·10−5,2.7190·10−5, and 2.0795·10−5, respectively. In the analysis of LV function, use of JMC had a small but statistically significant (p < 0.05) effect on several parameters: it increased LV volumes and standard deviation of phase angle histogram, and it decreased ejection fraction, global wall motion, and lateral, septal, and apical perfusion.ConclusionsCompared to standard OSEM algorithm, RBM-OSEM and JMC-OSEM both improve image quality under motion. Motion compensation has a minor effect on LV functional parameters.

Assessment of four different cardiac softwares for evaluation of LVEF with CZT-SPECT vs CMR in 48 patients with recent STEMI

PurposeTo compare, vs CMR, four softwares: quantitative gated SPECT (QGS), myometrix (MX), corridor 4DM (4DM), and Emory toolbox (ECTb) to evaluate left ventricular ejection fraction (LVEF), end-systolic (ESV), and end-diastolic volumes (EDVs) by gated MPI CZT-SPECT. Methods48 patients underwent MPI CZT-SPECT and CMR 6 weeks after STEMI, LV parameters were measured with four softwares at MPI CZT-SPECT vs CMR. We evaluated (i) concordance and correlation between MPI CZT-SPECT and CMR, (ii) concordance MPI CZT-SPECT/CMR for the categorical evaluation of the left ventricular dysfunction, and (iii) impacts of perfusion defects > 3 segments on concordance. ResultsLVEF: LCC QGS/CMR = 0.81 [+ 2.2% (± 18%)], LCC MX/CMR = 0.83 [+ 1% (± 17.5%)], LCC 4DM/CMR = 0.73 [+ 3.9% (± 21%)], LCC ECTb/CMR = 0.69 [+ 6.6% (± 21.1%)]. ESV: LCC QGS/CMR = 0.90 [− 8 mL (± 40 mL)], LCC MX/CMR = 0.90 [− 9 mL (± 36 mL)], LCC 4DM/CMR = 0.89 [+ 4 mL (± 45 mL)], LCC ECTb/CMR = 0.87 [− 3 mL (± 45 mL)]. EDV: LCC QGS/CMR = 0.70 [− 16 mL (± 67 mL)], LCC MX/CMR = 0.68 [− 21 mL (± 63 mL], LCC 4DM/CMR = 0.72 [+ 9 mL (± 73 mL)], LCC ECTb/CMR = 0.69 [+ 10 mL (± 70 mL)]. ConclusionQGS and MX were the two best-performing softwares to evaluate LVEF after recent STEMI.

Reproducibility of LVEF, LV volumes, and LV mass between Rubidium-82 PET/CT scans in young healthy volunteers using two commercially available software packages

BackgroundGlobal functional parameters are available from electrocardiographic gated Rubidium-82 positron emission tomography/computed tomography (82Rb-PET/CT). However, the reproducibility of these data is not clarified. We aimed to investigate reproducibility of left ventricular ejection fraction (LVEF), endsystolic volume (ESV), enddiastolic volume (EDV), and left ventricular (LV) mass between two scans and between two commercially available software packages. Methods and ResultsForty healthy young volunteers underwent two 82Rb-PET/CT rest and adenosine stress scans obtaining global functional parameters. Corridor4DM (4DM) and Quantitative Gated SPECT (QGS) were used for analyses. Mean (± SD) age was 24 ± 4 years and 50% were men. High reproducibility of all parameters was found between scans and this was true for both software packages. LVEF at rest with 4DM: mean difference (95% CI) − 1.1 (− 3.0 to 0.8), P = .25, limits of agreement: − 12.8 to 10.6. Significant differences were found between software packages on all functional parameters (P < .0001). ConclusionHigh reproducibility was found between scans when measuring LVEF, ESV, EDV, and LV mass from 82Rb-PET/CT. However, concordance between parameter measures was poor when comparing the two software packages. Thus, global functional parameter measures are reliable, but the same software package should be used within a study and when comparing absolute values.

The impact of frame numbers on cardiac ECG-gated SPECT images with interpolated extra frames using echocardiography.

Background: Cardiac echocardiography and cardiac ECG-gated single-photon emission computed tomography (SPECT) are the most common modalities for left ventricle (LV) volumes and function assessment. The temporal resolution of SPECT images is limited and an ECG provides better temporal resolution. This study investigates the impact of frame numbers on images in terms of qualitative and quantitative assessments. Methods: In this study, 5 patients underwent echocardiography and cardiac ECG-gated SPECT imaging, and 5 standard views of the LV were recorded to determine LV walls boundaries and volumes. Also, 2 original images with 8 frames and 16 frames per cardiac cycle were recorded simultaneously in a single gantry orbit. Using the data extracted from the LV model, 8 extra new frames were created with interpolation between existing frames of the original 8-frame image. Three series of images (8 and 16 original and 16 interpolated) were reconstructed separately. LV volumes and ejection fraction (EF) were calculated using Quantitative Gated SPECT (QGS) software. Results: Compared to the original 8-frame gating, original 16-frame gated images resulted in larger end-diastole volume (EDV) (mean ± SD: 68.6 ± 27.11 mL vs 66.2±25.41 mL, p<0.001), smaller end-systole volume (ESV) (mean ± SD: 24.6±8.7 mL vs 26±7.3 mL, p<0.001), and higher EF (64% vs 60.2%, p<0.001). The results for the interpolated series were also different from the original images (closer to the original 16-frame series rather than 8-frame). Conclusion: Changing the frame number from 8 to 16 in cardiac ECG-gated SPECT images caused a significant change in LV volumes and EF. Frame interpolation with sophisticated algorithms can be used to improve the temporal resolution of SPECT images.

Cardiac Resynchronization Therapy for Improving Non-Uniform Thickening of Left Ventricular Wall: Assessment by Quantitative Gated Myocardial Perfusion SPECT.

Cardiac resynchronization therapy (CRT) improves cardiac dyssynchrony in heart failure patients with a wide QRS electrocardiogram (ECG). Assessment of left ventricular (LV) dyssynchrony using echocardiography or other imaging modalities is important to predict CRT effectiveness. In this study, we retrospectively evaluated cardiac nuclear imaging of ECG-gated myocardial perfusion single-photon emission computed tomography (SPECT) with 99mTc-sestamibi for CRT candidate (n = 120) with severe heart failure and wide QRS (> 120 msec) in ECG. To analyze LV non-uniformity, we used the quantitative gated SPECT (QGS) software to calculate changes in regional LV wall thickness during a cardiac cycle (i.e., wall thickening scores). Cardiac events (heart failure, ventricular arrhythmias and cardiac death) after CRT during 38 ± 22 (SD) months were also evaluated. In 97 of 120 patients who underwent QGS before and 6 months after CRT, CRT homogenized non-uniform wall thickening between septal and lateral of the LV especially in CRT responders. This observation was indicated as increase in the lateral deflection (XWT) of wall thickening scores before CRT and its decrease after CRT. In 120 patients with QGS before CRT, the larger XWT before CRT (≥ 16.5) predicted better prognoses after CRT. This finding was similarly observed even in patients with narrower baseline QRS (≤ 140 msec; n = 41 of 120), who usually have less benefits from CRT. In conclusion, CRT improved non-uniformity of wall thickening between the LV septal and lateral regions evaluated using QGS, which is predictive of better prognosis in the chronic phase after CRT.

Shortened acquisition time in simultaneous 99mTc-tetrofosmin and 123I-β-methyl-p-iodophenyl pentadecanoic acid dual-tracer imaging with cadmium-zinc-telluride detectors in patients undergoing primary coronary intervention for acute myocardial infarction.

The use of cadmium-zinc-telluride-based scanners may increase the clinical feasibility of simultaneous dual-isotope imaging. In the current study, we sought to investigate a potential acquisition time in simultaneous Tc-tetrofosmin/I-β-methyl-p-iodophenyl pentadecanoic acid dual-isotope imaging using a Discovery NM/CT 670 cadmium-zinc-telluride. Simultaneous Tc-tetrofosmin/I-β-methyl-p-iodophenyl pentadecanoic acid dual-isotope imaging was performed in 29 patients who had undergone primary percutaneous coronary intervention for acute myocardial infarction. Referenced images with an acquisition time of 65 s/view (16.25 min) were reframed to produce images with acquisition times of 33, 16, and 8 s/view. The values for the quantitative-gated single-photon emission computed tomography (SPECT) and the quantitative perfusion SPECT were compared. The quantitative-gated SPECT values for images with 33, 16, and 8 s/views showed good consistency with those for 65 s/view (the lower 95% confidence intervals for the intraclass correlation were ≥0.80). The quantitative perfusion SPECT values for Tc-tetrofosmin images with 33, 16, and 8 s/views also showed good consistency with those for 65 s/view; however, the quantitative perfusion SPECT values for I-β-methyl-p-iodophenyl pentadecanoic acid images with an acquisition time of 8 s/view were not consistent with the reference acquisition time of 65 s/view. The quantitative-gated SPECT and quantitative perfusion SPECT values obtained from images with shorter acquisition times correlated with the values obtained from images with a reference acquisition time of 65 s/view; however, tracer-specific predisposition should be considered. These findings suggest that it is possible to reduce acquisition time when performing simultaneous Tc-tetrofosmin/I-β-methyl-p-iodophenyl pentadecanoic acid dual-tracer imaging with the novel cadmium-zinc-telluride scanner.

P3357Reproducibility of myocardial flow reserve estimation using Rubidium-82 PET/CT scans in healthy, young volunteers: comparison of three commercially available software packages

Abstract Background The use of myocardial blood flow (MBF) reserve assessed with cardiac positron emission computed tomography (PET/CT) is well established and contain important prognostic information e.g. in patients with ischaemic heart disease. However, perfusion data must be interpreted under consideration of the limitations of the method. It has previously been concluded that software specific age and sex matched normal values for MBF reserve should be used as reference. Furthermore, reproducibility between scans seems to vary more in persons with higher risk of cardiovascular disease than in those with no risk factors. Comparison between scans has previously been conducted using dipyridamole as a stressor. However, no former studies have addressed this using adenosine as stressor for 82Rb-PET/CT in a combined study of scan reproducibility and software comparison. Purpose The aim of this study was to investigate reproducibility of rest- and adenosine stress 82Rb-PET/CT estimated MBF reserve in healthy young volunteers between two scans analysed with three commercially available software packages. Methods Forty healthy young volunteers completed two 82Rb-PET/CT rest- and adenosine stress scans obtaining myocardial blood flow (MBF) and MBF reserve, syngo MBF, Quantitative Gated SPECT (QGS) and Corridor4DM (4DM) were used for analyses. Results Fifty percent were men and mean (±SD) age was 24±4 years. Varying reproducibility of MBF reserve between scans was found for the different software packages. MBF reserve with syngo.MBF (Figure 1A): mean difference (95% CI) 0.26 (−0.03 to 0.54), P=0.07, limits of agreement: −1.43 to 1.95, MBF reserve with QGS (Figure 1B): mean difference (95% CI) 0.19 (−0.08 to 0.46), P=0.15, limits of agreement: −1.38 to 1.76 and MBF reserve with 4DM (Figure 1C): mean difference (95% CI) 0.08 (−0.17 to 0.34), P=0.50, limits of agreement: −1.37 to 1.53. Significantly higher MBF reserve was measured with 4DM (mean±SD: 4.00±0.96) compared to syngo.MBF (mean±SD 3.75±0.91, P&lt;0.001) and QGS (mean±SD 3.75±0.89, P&lt;0.0001), whereas concordance between MBF reserve measured by syngo.MBF and QGS was high (P=0.87). Figure 1 Conclusions All software packages identified the participants with flow values in the high end of the normal range, as expected for healthy volunteers. Varying reproducibility of MBF reserve was found between scans for the different software packages and 4DM seemed to have the highest inter-scan reproducibility. Concordance between MBF reserve measures was high between syngo.MBF and QGS whereas higher MBF reserve measures was conducted from 4DM in comparison with the two other software packages. Our results suggest that MBF analysed with syngo.MBF and QGS may be mutually comparable but that 4DM may be preferred for analyses due to possibly higher scan to scan reproducibility.

Are there normal values of phase analysis parameters for left ventricular dyssynchrony in patients with no structural cardiomyopathy?: a systematic review.

ECG-gated single photon emission computed tomography (SPECT) myocardial perfusion scintigraphy combined with phase analysis allows for the assessment of left ventricular dyssynchrony. However, there are several software programs available thereby introducing variability in outcome and normal values. The aim of this systematic review was to evaluate the variability between different programs as currently available in literature with a focus on normal values. A systematic review was performed using the Embase, LILACS and Medline databases looking for articles reporting on normal values of the most used phase analysis parameters. The search resulted in 110 articles from Medline, 349 from Embase and one from LILACS. After exclusion of duplicate articles, 370 documents remained. Of these only 13 were deemed eligible for the systematic review. Phase SD and bandwidth are the main parameters used in dyssynchrony analysis. Most articles reviewed here used the Emory Cardiac ToolBox (ECTb) to determine the phase analysis parameters values, which varied greatly among the four software tested. The bandwidth and phase SD calculated by the Quantitative Gated SPECT (QGS) tends to be smaller than that calculated by the ECTb. In relation to the bandwidth, ECTb and cardioREPO (cREPO) have higher values than the other software programs. The value of entropy obtained from 4DM is lower than those obtained from QGS and cREPO. We found that normal values of phase analysis can vary among software programs and can be different even when the same software is used.

Clinical value of 99Tcm-MIBI gated myocardial perfusion imaging in evaluating sarcoglycanopathy.

The purpose of this study was to analyse the diagnostic value of gated myocardial perfusion imaging (G-MPI) in the evaluation of myocardial injury in sarcoglycanopathy. Twenty-eight patients diagnosed with sarcoglycanopathy were evaluated using 99m- -methoxyisobutylisonitrile(99Tcm-MIBI) G-MPI. The data was processed into tomographic images, and the left ventricular function was analysed using quantitative gated SPECT (QGS) to assess the degree of impairment in myocardial and cardiac function. The images of 23 of the patients (82.1%) were positive. Two hundred and twenty-nine sub-segments with abnormal lesions were detected out of 391 cardiac sub-segments of these 23 positive cases. According to the segmental abnormalities, the cases were divided into two cases (8.7%) with single abnormal wall segment, six cases (26.1%) with two abnormal wall segments, and 15 cases (65.2%) with three or more abnormal wall segments or scattered lesions. 99Tcm-MIBI G-MPI can objectively show impaired myocardium in patients with sarcoglycanopathy. Therefore, this method is helpful for early diagnosis and follow-up of myocardial damage.

Evaluation of left ventricular volumes and ejection fraction by 99mTc-MIBI gated SPECT and 18F-FDG gated PET in patients with prior myocardial infarction

BackgroundThis study aimed to compare the accuracy of gated-SPECT (GSPECT) and gated-PET (GPET) in the assessment of left ventricular (LV) end-diastolic volumes (EDVs), end-systolic volumes (ESVs) and LV ejection fractions (LVEFs) among patients with prior myocardial infarction (MI). MethodsOne hundred and sixty-eight consecutive patients with MI who underwent GSPECT and GPET were included. Of them, 76 patients underwent CMR in addition to the two imaging modalities. The measurements of LV volumes and LVEF were performed using Quantitative Gated SPECT (QGS), Emory Cardiac Toolbox (ECTB), and 4D-MSPECT (4DM). ResultsThe correlation between GPET, GSPECT, and CMR were excellent for LV EDV (r = 0.855 to 0.914), ESV (r = 0.852 to 0.949), and LVEF (r = 0.618 to 0.820), as calculated from QGS, ECTB, and 4DM. In addition, subgroup analysis revealed that EDV, ESV, and LVEF measured by GPET were accurate in patients with different extents of total perfusion defect (TPD), viable myocardium, and perfusion/metabolic mismatch. Furthermore, multivariate regression analysis identified that mismatch score was associated with the difference in EDV (P < 0.05) measurements between GPET and CMR. ConclusionsIn patients with MI, LV volumes and LVEF scores measured by both GSPECT and GPET imaging were comparable to those determined by CMR, but should not be interchangeable in individual patients.

Cardiac motion correction for improving perfusion defect detection in cardiac SPECT at standard and reduced doses of activity

In cardiac SPECT perfusion imaging, cardiac motion can lead to motion blurring of anatomical detail and perfusion defects in the reconstructed myocardium. In this study, we investigated the potential benefit of cardiac motion correction for improving the detectability of perfusion defects. We considered a post-reconstruction motion correction (PMC) approach in which the image motion between two cardiac gates is obtained with optical flow estimation.In the experiments, we demonstrated the proposed post-reconstruction motion correction with optical flow estimation (PMC-OFE) approach on a set of clinical acquisitions from 194 subjects. We quantified the detectability of perfusion defects in the reconstructed images by using the total perfusion deficit scores, calculated by the clinical software tool QPS, and conducted a receiver-operating-characteristic (ROC) study to obtain the detection performance. Besides imaging with conventional standard dose, we also evaluated the approach for reduced dose SPECT imaging where the imaging dose was retrospectively reduced to 50%, 25%, and 12.5% of the standard dose. The proposed PMC-OFE approach achieved at each dose level higher area-under-the-ROC-curve (AUC) for perfusion defect detection than the traditional approach of using ungated data (Non-MC) (p -value < 0.05); in particular, with half dose, PMC-OFE achieved AUC = 0.813, which is comparable to Non-MC with standard dose (AUC = 0.795). Moreover, the proposed PMC-OFE approach also outperformed the ‘Motion Frozen’ (MF) method implemented in the clinical quantitative gated SPECT (QGS) software. In particular, at 25% and 12.5% of standard dose, the AUC values obtained by PMC-OFE are 0.788 and 0.779, respectively, compared to 0.758 and 0.731 for MF (p -value < 0.05).

Comparison of Left Ventricular Phase Parameters Analysis between Two Software Programs in Patients with Normal Gated Single-photon Emission Computed Tomography-Myocardial Perfusion Imaging.

Background:Phase analysis can be easily performed by different software to assess the left ventricular dyssynchrony from gated single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) with high precision. However, the normal values of histogram bandwidth (HBW) and phase standard deviation (PSD) and their comparison using different programs have not been fully elucidated and actively being evaluated at present. The aim of this study was to determine the phase analysis parameters values and to compare the phase indices of two commonly used programs in a group of patients with normal gated SPECT-MPI.Methods:Phase parameters were retrospectively evaluated in 138 consecutive nondiabetic patients having a normal gated SPECT-MPI using the quantitative gated SPECT (QGS) and Emory Cardiac Toolbox (ECTb) software. HBW, PSD, and phase entropy were calculated separately using both programs.Results:The fair correlation between software programs was observed. HBW and PSD in QGS and ECTb were 26.20 ± 9.7 and 25.46 ± 8.0 (r-value. 56, SEE 6.65) and 6.64 ± 2.5 and 7.65 ± 2.5 (r = 0.54, SEE 2.14), respectively. The value of phase entropy in QGS program was 45.08 ± 6.3. A fair correlation between phase entropy and PSD in QGS was observed (r = 0.44, 95% confidence interval-0.29–0.56).Conclusion:Phase analysis parameters derived from gated SPECT-MPI in patients with normal myocardial perfusion are program dependent and may differ. The results cannot be interchangeably used in the same patients.

Assessment of Left Ventricular Diastolic Function Using ECG-gated Myocardial Perfusion SPECT in Small Heart: Comparison with Ultrasound Echocardiography

Assessment of left ventricular (LV) diastolic function is important because it is possible to detect early sign of myocardial ischemia by this assessment. The purpose of this study was to compare between electrocardiogram (ECG) -gated myocardial perfusion single photon emission computed tomography (G-SPECT) and ultrasound echocardiography in assessment of LV diastolic function in the small heart (SH). The study population consisted of 144 patients who underwent both G-SPECT and ultrasound echocardiography. Peak filling rate (PFR), one-third mean filling rate (1/3 MFR) and the ratio of time to PFR to the RR interval (TPFR/RR) were calculated by quantitative gated SPECT (QGS) and heart risk view-F (HRV-F). Peak early mitral annular velocity (e') was used as the reference standard of LV diastolic function. There were 33 patients with end-systolic volume (ESV) of ≤10 ml (SH10), 51 patients with ESV of 11-20 ml (SH 20) and 60 patients with ESV of >20 ml (normal-sized heart: NH). In SH10, PFR calculated by QGS was not correlated with e'. However, that by HRV-F was significantly correlated with e' (r=0.47, p=0.006). On the other hand, 1/3 MFR and TPFR/RR calculated by QGS and HRV-F were not correlated with e' in SH10 and SH20. PFR, 1/3 MFR and TPFR/RR calculated by QGS and HRV-F were correlated with e' in NH.