Quantification of left ventricular volumes and ejection fraction from gated 99mTc-MIBI SPECT: MRI validation and comparison of the Emory Cardiac Tool Box with QGS and 4D-MSPECT.

The goal of this study was to validate the accuracy of the Emory Cardiac Tool Box (ECTB) in assessing left ventricular end-diastolic or end-systolic volume (EDV, ESV) and ejection fraction (LVEF) from gated (99m)Tc-methoxyisobutylisonitrile ((99m)Tc-MIBI) SPECT using cardiac MRI (cMRI) as a reference. Furthermore, software-specific characteristics of ECTB were analyzed in comparison with 4D-MSPECT and Quantitative Gated SPECT (QGS) results (all relative to cMRI). METHODS: Seventy patients with suspected or known coronary artery disease were examined using gated (99m)Tc-MIBI SPECT (8 gates/cardiac cycle) 60 min after tracer injection at rest. EDV, ESV, and LVEF were calculated from gated (99m)Tc-MIBI SPECT using ECTB, 4D-MSPECT, and QGS. Directly before or after gated SPECT, cMRI (20 gates/cardiac cycle) was performed as a reference. EDV, ESV, and LVEF were calculated using Simpson's rule. RESULTS: Correlation between results of gated (99m)Tc-MIBI SPECT and cMRI was high for EDV (R = 0.90 [ECTB], R = 0.88 [4D-MSPECT], R = 0.92 [QGS]), ESV (R = 0.94 [ECTB], R = 0.96 [4D-MSPECT], R = 0.96 [QGS]), and LVEF (R = 0.85 [ECTB], R = 0.87 [4D-MSPECT], R = 0.89 [QGS]). EDV (ECTB) did not differ significantly from cMRI, whereas 4D-MSPECT and QGS underestimated EDV significantly compared with cMRI (mean +/- SD: 131 +/- 43 mL [ECTB], 127 +/- 42 mL [4D-MSPECT], 120 +/- 38 mL [QGS], 137 +/- 36 mL [cMRI]). For ESV, only ECTB yielded values that were significantly lower than cMRI. For LVEF, ECTB and 4D-MSPECT values did not differ significantly from cMRI, whereas QGS values were significantly lower than cMRI (mean +/- SD: 62.7% +/- 13.7% [ECTB], 59.0% +/- 12.7% [4DM-SPECT], 53.2% +/- 11.5% [QGS], 60.6% +/- 13.9% [cMRI]). CONCLUSION: EDV, ESV, and LVEF as determined by ECTB, 4D-MSPECT, and QGS from gated (99m)Tc-MIBI SPECT agree over a wide range of clinically relevant values with cMRI. Nevertheless, any algorithm-inherent over- or underestimation of volumes and LVEF should be accounted for and an interchangeable use of different software packages should be avoided.     

Validation of 4D-MSPECT and QGS for quantification of left ventricular volumes and ejection fraction from gated <Superscript>99m</Superscript>Tc-MIBI SPET: comparison with cardiac magnetic resonance imaging

The main aim of this study was to validate the accuracy of 4D-MSPECT in the assessment of left ventricular (LV) end-diastolic/end-systolic volumes (EDV, ESV) and ejection fraction (LVEF) from gated technetium-99m methoxyisobutylisonitrile single-photon emission tomography (^99mTc-MIBI SPET), using cardiac magnetic resonance imaging (cMRI) as the reference method. By further comparing 4D-MSPECT and QGS with cMRI, the software-specific characteristics were analysed to elucidate clinical applicability. Fifty-four patients with suspected or proven coronary artery disease (CAD) were examined with gated ^99mTc-MIBI SPET (8 gates/cardiac cycle) about 60 min after tracer injection at rest. LV EDV, ESV and LVEF were calculated from gated ^99mTc-MIBI SPET using 4D-MSPECT and QGS. On the same day, cMRI (20 gates/cardiac cycle) was performed, with LV EDV, ESV and LVEF calculated using Simpsons rule. Both algorithms worked with all data sets. Correlation between the results of gated ^99mTc-MIBI SPET and cMRI was high for EDV [R=0.89 (4D-MSPECT), R=0.92 (QGS)], ESV [R=0.96 (4D-MSPECT), R=0.96 (QGS)] and LVEF [R=0.89 (4D-MSPECT), R=0.90 (QGS)]. In contrast to ESV, EDV was significantly underestimated by 4D-MSPECT and QGS compared to cMRI [130±45 ml (4D-MSPECT), 122±41 ml (QGS), 139±36 ml (cMRI)]. For LVEF, 4D-MSPECT and cMRI revealed no significant differences, whereas QGS yielded significantly lower values than cMRI [57.5%±13.7% (4D-MSPECT), 52.2%±12.4% (QGS), 60.0%±15.8% (cMRI)]. In conclusion, agreement between gated ^99mTc-MIBI SPET and cMRI is good across a wide range of clinically relevant LV volume and LVEF values assessed by 4D-MSPECT and QGS. However, algorithm-varying underestimation of LVEF should be accounted for in the clinical context and limits interchangeable use of software.     

Validation of an evaluation routine for left ventricular volumes,ejection fraction and wall motion from gated cardiac FDG PET: a comparison with cardiac magnetic resonance imaging

The aim of this study was to validate the estimation of left ventricular end-diastolic and end-systolic volumes (EDV, ESV) and ejection fraction (LVEF) as well as wall motion analysis from gated fluorine-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) in patients with severe coronary artery disease (CAD) using software originally designed for gated single-photon emission tomography (SPET). Thirty patients with severe CAD referred for myocardial viability diagnostics were investigated using a standard FDG PET protocol enhanced with gated acquisition (8 gates per cardiac cycle). EDV, ESV and LVEF were calculated using standard software designed for gated SPET (QGS). Wall motion was analysed using a visual four-point wall motion score on a 17-segment model. As a reference, all patients were also examined within a median of 3 days with cardiovascular cine magnetic resonance imaging (cMRI) (20 gates per cardiac cycle). Furthermore, all gated FDG PET data sets were reoriented in a second run with deliberately misaligned axes to test the quantification procedure for robustness. Correlation between the results of gated FDG PET and cMRI was very high for EDV and ESV ( R=0.96 and R=0.97) and for LVEF ( R=0.95). With gated FDG PET, there was a non-significant tendency to underestimate EDV (174+/-61 ml vs 179+/-59 ml, P=0.21) and to overestimate ESV (124+/-58 ml vs 122+/-60 ml, P=0.65), resulting in underestimated LVEF values (31.5%+/-9.4% vs 34.2%+/-12.4%, P<0.003). The results of reorientations 1 and 2 showed very high correlations (for all R>/=0.99). Segmental wall motion analysis revealed good agreement between gated FDG PET data and cMRI (kappa =0.62+/-0.03). In conclusion, despite small systematic differences which contributed mainly to the lower temporal resolution of gated FDG PET, agreement between gated FDG PET and cMRI was good across a wide range of volumes and LVEF values as well as for wall motion analysis. Therefore, gated FDG PET provides clinically relevant information on function and volumes, using the commercially available software package QGS.     

Quantification of left ventricular volumes and ejection fraction from gated <Superscript>99m</Superscript>Tc-MIBI SPECT: validation of an elastic surface model approach in comparison to cardiac magnetic resonance imaging, 4D-MSPECT and QGS

Purpose The segmentation algorithm ESM based on an elastic surface model was validated for the assessment of left ventricular volumes and ejection fraction from ECG-gated myocardial perfusion SPECT. Additionally, it was compared with the commercially available quantification packages 4D-MSPECT and QGS. Cardiac MRI was used as the reference method. Methods SPECT and MRI were performed on 70 consecutive patients with suspected or proven coronary artery disease. End-diastolic (EDV) and end-systolic (ESV) volumes and left ventricular ejection fraction (LVEF) were derived from SPECT studies by using the segmentation algorithms ESM, 4D-MSPECT and QGS and from cardiac MRI. Results ESM-derived values for EDV and ESV correlated well with those from cardiac MRI (correlation coeffients R = 0.90 and R = 0.95, respectively), as did the measurements for LVEF (R = 0.86). Both EDV and ESV were slightly overestimated for larger ventricles but not for smaller ventricles; LVEF was slightly overestimated irrespective of ventricle size. The above correlation coefficients are comparable to those for the 4D-MSPECT and QGS segmentation algorithms. However, results obtained with the three segmentation algorithms are not interchangeable. Conclusion The ESM algorithm can be used to assess EDV, ESV and LVEF from gated perfusion SPECT images. Overall, the performance was similar to that of 4D-MSPECT and QGS when compared with cardiac MRI. Results obtained with the three tested segmentation methods are not interchangeable, so that the same algorithm should be used for follow-up studies and control subjects.     

滤波反投影法和OSEM重建图像测量心功能参数的比较

目的比较静息门控心肌显像滤波反投影法（FBP）和OSEM重建图像后用定量门控心肌断层显像（QGS）、四维模型心肌断层显像（4D—MSPECT）、爱莫瑞心脏工具箱（ECToolbox）软件测量的心功能参数。方法临床疑诊或确诊冠心病患者144例,均行^99Tc^m-MIBI静息门控心肌SPECT显像,所有患者均用FBP和OSEM重建图像,用QGS、4D—MSPECT、ECToolbox软件计算心功能参数LVEF,EDV和ESV,采用Bland—Altman法检验2种重建方法的一致性,配对t检验方法检验心功能参数差异,相关性分析用直线回归分析。结果FBP和OSEM重建测量的心功能参数一致性和相关性好（r均〉0．93,P均〈0．001）。QGS软件FBP重建测得的EDV低于OSEM重建测得的EDV,其他2种软件为FBP高于OSEM[QGS：（82．2±39．1）ml和（83．5±40．8）ml,t=-2．53,P〈0．05;4D—MSPECT：（93．5±46．9）ml和（88．8±45．2）ml,t=5．95,P〈0．01;ECToolbox：（106．4±51．1）ml和（100．8±49．0）ml,t=3．99,P〈0．01]。对于ESV,4D-MSPECT软件FBP测量值高于OSEM[（37．5±41．4）ml和（34．8±37．6）ml,t=3．92,P〈0．01]。QGS软件FBP测得的LVEF低于OSEM测得的LVEF[（62．1±16．9）％和（63．1±16．1）％,t=-3．14,P〈0．01]。ECToolbox软件FBP测得的LVEF高于用OSEM测得的LVEF[（74．1±18．8）％和（71．3±17．1）％,t=5．28,P〈0．01]。结论2种重建方法所测量的心功能参数虽然相关性和一致性很好,但某些参数值差异有统计学意义。     

Gated cardiac 13N-NH3 PET for assessment of left ventricular volumes, mass, and ejection fraction: comparison with electrocardiography-gated 18F-FDG PET.

The purpose of this study was to evaluate myocardial electrocardiography (ECG)-gated 13N-ammonia (13N-NH3) PET for the assessment of cardiac end-diastolic volume (EDV), cardiac end-systolic volume (ESV), left ventricular (LV) myocardial mass (LVMM), and LV ejection fraction (LVEF) with gated 18F-FDG PET as a reference method. METHODS: ECG-gated 13N-NH3 and 18F-FDG scans were performed for 27 patients (23 men and 4 women; mean+/-SD age, 55+/-15 y) for the evaluation of myocardial perfusion and viability. For both 13N-NH3 and 18F-FDG studies, a model-based image analysis tool was used to estimate endocardial and epicardial borders of the left ventricle on a set of short-axis images and to calculate values for EDV, ESV, LVEF, and LVMM. RESULTS: The LV volumes determined by 13N-NH3 and 18F-FDG were 108+/-60 mL and 106+/-63 mL for ESV and 175+/-71 mL and 169+/-73 mL for EDV, respectively. The LVEFs determined by 13N-NH3 and 18F-FDG were 42%+/-13% and 41%+/-13%, respectively. The LVMMs determined by 13N-NH3 and 18F-FDG were 179+/-40 g and 183+/-43 g, respectively. All P values were not significant, as determined by paired t tests. A significant correlation was observed between 13N-NH3 imaging and 18F-FDG imaging for the calculation of ESV (r=0.97, SEE=14.1, P<0.0001), EDV (r=0.98, SEE=15.4, P<0.0001), LVEF (r=0.9, SEE=5.6, P<0.0001), and LVMM (r=0.93, SEE=15.5, P<0.0001). CONCLUSION: Model-based analysis of ECG-gated 13N-NH3 PET images is accurate in determining LV volumes, LVMM, and LVEF. Therefore, ECG-gated 13N-NH3 can be used for the simultaneous assessment of myocardial perfusion, LV geometry, and contractile function.     

Evaluation of left ventricular volumes and ejection fraction by gated SPECT and cardiac MRI in patients with dilated cardiomyopathy

Purpose  

The goal of this study was to evaluate the accuracy of gated single photon emission computed tomography (SPECT) in the assessment of left ventricular (LV) end-diastolic/end-systolic volumes (EDV, ESV) and ejection fraction (LVEF) in patients with dilated cardiomyopathy, using cardiac magnetic resonance imaging (MRI) as the reference method. Furthermore, software-specific characteristics of Quantitative Gated SPECT (QGS), Emory Cardiac Toolbox (ECTB) and 4D-MSPECT were analysed.     

Evaluation of left ventricular volumes and ejection fraction by gated myocardial perfusion SPECT versus cardiac MRI

It is stated that cardiac MRI imaging can provide accurate estimation of left ventricular (LV) volumes and ejection fraction (EF). The purpose of this study was to evaluate the accuracy of gated myocardial perfusion SPECT for assessment of LV end-diastolic volume (EDV), end-systolic volume (ESV) and EF, using cardiac MRI as the reference methods/(methodology). Gated myocardial perfusion SPECT images were analyzed with two different quantification software, QGS and 4D-MSPECT. Thirty-four consecutive patients were studied. Myocardial perfusion SPECT and cardiac MRI had excellent intra/interobserver reproducibility. Correlation between the results of gated myocardial perfusion SPECT and cardiac MRI were high for EDV and EF. However, ESV and EDV were significantly underestimated by gated myocardial perfusion SPECT compared to cardiac MRI. Moreover, gated myocardial perfusion SPECT overestimated EF for small heart. One reason for the difference in volumes and EF is the delineation of the endocardial border. Cardiac MRI has higher spatial resolution. We should understand the differences of volumes and EF as determined by gated myocardial perfusion SPECT and cardiac MRI.     

Comparison of two software in gated myocardial perfusion single photon emission tomography, for the measurement of left ventricular volumes and ejection fraction, in patients with and without perfusion defects

Emory cardiac toolbox (ECTb) and quantitative gated single photon emission tomography - SPET (QGS) software are the two most often used techniques for automatic calculation of left ventricular volumes (LVV) and ejection fraction (LVEF). Few studies have shown that these software are not interchangeable, however the effect of perfusion defects on performance of these software has not been widely studied. The aim of this study was to compare the performance of QGS and ECTb for the calculation of LVEF, end-systolic volume (ESV) and end-diastolic volume (EDV) in patients with normal and abnormal myocardial perfusion. One hundred and forty-four consecutive patients with suspected coronary artery disease underwent a two-day protocol with dipyridamole stress/rest gated technetium-99m-methoxy isobutyl isonitrile ((99m)Tc-sestamibi) myocardial perfusion (GSPET) (8 gates/cardiac cycles). Rest GSPET scintiscan findings were analyzed using QGS and ECTb. Correlation between the results of QGS and ECTb was greater than 90%. In patients with no perfusion defects, EDV and LVEF using ECTb, were significantly higher than using QGS (P<0.001), whereas no significant difference was noticed in ESV (P=0.741). In patients with perfusion defects, also ECTb yielded significantly higher values for EDV, ESV and LVEF than QGS (P<0.001). In tomograms of patients with perfusion defects, mean differences of EDV and ESV between the two software, were significantly higher than in tomograms of patients without defects (P<0.001), while for LVEF this difference was not significant (P= 0.093). Patients were classified into three subgroups based on the summed rest score (SRS); G1: patients with SRS < or = 3 (n=109), G2: patients with 4 < or = SRS < or = 8 (n=13) and G3: patients with SRS > or = 9 (n=22). One-way ANOVA showed that the mean differences of EDV and ESV values between ECTb and QGS between the subgroups were significant (P<0.001 for both parameters), while no significant difference was noticed between the subgroups, as for the mean difference of LVEF, calculated by the two software (P=0.07). By increasing SRS, the EDV and ESV values were overestimated to a higher level by the ECTb as compared to the QGS software. Linear regression analysis showed that the difference in LVV values, between the two software increased, when SRS also increased (P<0.001). In conclusion, correlation between QGS and ECTb, software was very good both in patients with and without perfusion defects. In patients with perfusion defects, calculated LVEF, ESV and EDV values are higher using ECTb compared to the QGS software. However, the more extensive the perfusion defect was, the greater the difference of LVV between these two software. For the follow up of patients, we suggest the use of a single software either QGS or ECTb, for serial measurements of LV function.     

Clinical usefulness of ECG-gated18F-FDG PET combined with99mTc-MIBI gated SPECT for evaluating myocardial viability and function

OBJECTIVES: This study sought to evaluate an imaging approach using gated 99mTc-MIBI (MIBI) SPECT and gated 18F-FDG (FDG) PET for assessment of myocardial viability and cardiac function. METHODS: Forty-eight patients (38 men, mean age 68.1 +/- 9.6 years) underwent ECG-gated FDG PET and MIBI SPECT within a week. The baseline diagnoses were coronary artery disease (31), mitral regurgitation (1), paroxysmal arrhythmia (10), and dilated cardiomyopathy (6). The gated FDG PET data were analyzed using pFAST software, and the gated MIBI SPECT data were analyzed using QGS software. Fifteen patients were diagnosed with myocardial infarction, and follow-up study was performed to assess the functional outcome four months later. An improvement in LVEF of >5% was defined as significant. The LV myocardium was divided into 17 segments, and regional defect scores were visually assessed using a 4-point scale for each segment (0 = normal, 1 = mildly reduced, 2 = moderately reduced, 3 = absent). A segment with a greater defect score on MIBI SPECT than on FDG PET was defined as a mismatch. The patients were divided into two groups: those with at least two mismatched segments (MM-group), and those with none or one (M-group). RESULTS: LVEF, EDV and ESV measured by gated FDG PET were highly correlated with those obtained by gated MIBI SPECT (r = 0.848, 0.855 and 0.911, p < 0.0001, respectively). The mean values of LVEF did not differ significantly, but EDV and ESV obtained by gated FDG PET were significantly grater than those obtained by gated MIBI SPECT (p < 0.0001). In 15 patients diagnosed with myocardial infarction, a significant association (p < 0.05) was found between the relative uptake of FDG PET and MIBI SPECT and the functional outcome 4 months later. Global LV function improved in 6 of the 8 patients showing mismatch but in only 1 of the 7 patients with matched defects, resulting in a sensitivity of 86% and specificity of 75%. The overall accuracy to predict global functional outcome was high (80%). CONCLUSION: This imaging approach allows accurate evaluation of myocardial viability. Furthermore, the high correlations of gated FDG PET and gated MIBI SPECT measurements hold promise for the assessment of left ventricular function using gated FDG PET.     

Gated SPECT evaluation of left ventricular function using a CZT camera and a fast low-dose clinical protocol: comparison to cardiac magnetic resonance imaging

Purpose

CZT technology allows ultrafast low-dose myocardial scintigraphy but its accuracy in assessing left ventricular function is still to be defined.

Methods

The study group comprised 55 patients (23 women, mean age 63?±?9 years) referred for myocardial perfusion scintigraphy. The patients were studied at rest using a CZT camera (Discovery NM530c; GE Healthcare) and a low-dose ^99mTc-tetrofosmin clinical protocol (mean dose 264?±?38 MBq). Gated SPECT imaging was performed as a 6-min list-mode acquisition, 15 min after radiotracer injection. Images were reformatted (8-frame to 16-frame) using Lister software on a Xeleris workstation (GE Healthcare) and then reconstructed with a dedicated iterative algorithm. Analysis was performed using Quantitative Gated SPECT (QGS) software. Within 2 weeks patients underwent cardiac magnetic resonance imaging (cMRI, 1.5-T unit CVi; GE Healthcare) using a 30-frame acquisition protocol and dedicated software for analysis (MASS 6.1; Medis).

Results

The ventricular volumes obtained with 8-frame QGS showed excellent correlations with the cMRI volumes (end-diastolic volume (EDV), r?=?0.90; end-systolic volume (ESV), r?=?0.94; p?<?0.001). However, QGS significantly underestimated the ventricular volumes (mean differences: EDV, ?39.5?±?29 mL; ESV, ?15.4?±?22 mL; p?<?0.001). Similarly, the ventricular volumes obtained with 16-frame QGS showed an excellent correlations with the cMRI volumes (EDV, r?=?0.92; ESV, r?=?0.95; p?<?0.001) but with significant underestimations (mean differences: EDV, ?33.2?±?26 mL; ESV, ?17.9?±?20 mL; p?<?0.001). Despite significantly lower values (47.9?±?16 % vs. 51.2?±?15 %, p?<?0.008), 8-frame QGS mean ejection fraction (EF) was closely correlated with the cMRI values (r?=?0.84, p?<?0.001). The mean EF with 16-frame QGS showed the best correlation with the cMRI values (r?=?0.91, p?<?0.001) and was similar to the mean cMRI value (49.6?±?16 %, p not significant). Regional analysis showed a good correlation between both 8-frame and 16-frame QGS and cMRI wall motion score indexes (8-frame WMSI, r?=?0.85; 16-frame WMSI, r?=?0.89; p?<?0.01).

Conclusion

Low-dose gated SPECT with a CZT camera provides ventricular volumes that correlate well with cMRI results despite significant underestimation in the measure values. EF estimation appeared to be more accurate with 16-frame reformatted images than with 8-frame images.     

Left ventricular volumes and ejection fraction calculated from quantitative electrocardiographic-gated 99mTc-tetrofosmin myocardial SPECT.

We compared the left ventricular (LV) end-diastolic volume (EDV), end-systolic volume (ESV) and ejection fraction (LVEF) as calculated by Cedars automated quantitative gated SPECT (QGS) to those determined by first-pass radionuclide angiography (FPRNA) and contrast left ventriculography (LVG) in a group of 21 patients (mean age 61.4 +/- 9.2 y). METHODS: A total of 740 MBq 99mTc-tetrofosmin was administered rapidly into the right cubital vein at rest, and FPRNA was performed using a multicrystal gamma camera. One hour after injection, QGS was performed with a temporal resolution of 10 frames per R-R interval. LVG was performed within 2 wk. RESULTS: The EDV, ESV and LVEF calculated by QGS were highly reproducible (intraobserver, r = 0.99, r = 0.99 and r = 0.99, respectively; interobserver, r = 0.99, r = 0.99 and r = 0.99, respectively; P < 0.01) and were more consistent than those determined by FPRNA (intraobserver, r = 0.97, r = 0.95 and r = 0.93, respectively; interobserver, r = 0.86, r = 0.96 and r = 0.91, respectively; P < 0.01). There was a good correlation between EDV, ESV and LVEF by FPRNA and those by LVG (r = 0.61, r = 0.72 and r = 0.91, respectively; P < 0.01), and there was an excellent correlation between QGS and LVG (r = 0.73, r = 0.83 and r = 0.87, respectively; P < 0.01). The mean EDV by QGS (100 +/- 11.3 mL) was significantly lower than by FPRNA (132 +/- 16.8 mL) or LVG (130 +/- 8.1 mL), and the mean ESV by QGS (53.8 +/- 9.3 mL) was lower than by FPRNA (73.0 +/- 13.3 mL). Ejection fraction values were highest by LVG (57.1% +/- 3.2%), then QGS (51.8% +/- 3.0%) and FPRNA (48.9% +/- 2.4%). CONCLUSION: QGS gave more reproducible results than FPRNA. LV volumes and LVEF calculated by QGS correlated well to those by LVG.     

Age- and gender-specific differences in left ventricular cardiac function and volumes determined by gated SPET

The aim of this study was to determine normative volumetric data and ejection fraction values derived from gated myocardial single-photon emission tomography (SPET) using the commercially available software algorithm QGS (quantitative gated SPET). From a prospective database of 876 consecutive patients who were referred for a 2-day stress-rest technetium-99m tetrofosmin (925 MBq) gated SPET study, 102 patients (43 men, 59 women) with a low (<10%) pre-test likelihood of coronary disease were included (mean age 57.6 years). For stress imaging, a bicycle protocol was used in 79 of the patients and a dipyridamole protocol in 23. Left ventricular ejection fraction (LVEF) and end-diastolic and -systolic volumes (EDV and ESV) were calculated by QGS. EDV and ESV were corrected for body surface area, indicated by EDVi and ESVi. To allow comparison with previous reports using other imaging modalities, men and women were divided into three age groups (<45 years, > or =45 years but <65 years and > or =65 years). Men showed significantly higher EDVi and ESVi values throughout and lower LVEF values when compared with women in the subgroup > or =65 years (P<0.05, ANOVA). Significant negative and positive correlations were found between age and EDVi and ESVi values for both women and men and between LVEF and age in women (Pearson P< or =0.01). LVEF values at bicycle stress were significantly higher than at rest (P=0.000, paired t test), which was the result of a significant decrease in ESV (P=0.003), a phenomenon which did not occur following dipyridamole stress (P=0.409). The data presented suggest that LVEF and EDVi and ESVi as assessed by QGS are strongly gender-specific. Although the physiological significance of these results is uncertain and needs further study, these findings demonstrate that the evaluation of cardiac function and volumes of patients by means of QGS should consider age- and gender-matched normative values.     

Assessment of ECG-gated myocardial SPECT analysis program with cardiac phantom and clinical data]

PURPOSES: ECG-gated myocardial SPECT program (QGS) is coming into wide use. This program permits measurement of end-diastolic volume (EDV), and end-systolic volume (ESV) and ejection fraction (EF) by automatic detection of myocardial edges. We assessed the reproducibility, accuracy, factors that affect the measurement of these indices using a cardiac phantom and clinical data. METHODS: In the phantom study, we evaluated the effects of ventricular volume, location, absorption, acquisition time, enlarged acquisition and pre-filter on the calculated indices. In the clinical study using 99mTc-MIBI, reproducibility between 2 observers, comparison with left ventriculography and effects of pre-filter were assessed. In clinical cases of 201TI and 123I-BMIPP, left ventricular volume and EF were also analyzed by QGS with various pre-filters. RESULTS: Although the true phantom volumes (y) and calculated volumes (x) showed an excellent linear correlation (y = 0.94x - 13.8, r = 0.999), calculated volumes were significantly under-estimated by 14.5-33.8%. An absorbent material around the phantom caused reduction in calculated volumes by 4.1-9.1%. Duration of acquisition times, 3 to 60 seconds per projection, did not influence the calculation of the parameters. With enlarged data collection, calculated volume (37 ml) was larger than that of normal acquisition (33 ml). When the cut-off frequency of Butterworth filter was changed, these indices of volume and EF were almost stable over 0.41 cycle/cm. There was an excellent correlation in intra-observer measurements for EDV (r = 0.998, p < 0.0001), ESV (r = 0.998, p < 0.0001) and EF (r = 0.995, p < 0.0001). In comparison with left ventriculography, correlation of parameters was good in ESV (r = 0.91, p < 0.0001), EF (r = 0.88, p < 0.0001), but was fair in EDV (r = 0.78, p < 0.0001). The QGS program underestimated EDV, ESV and EF. CONCLUSION: QGS program with gated SPECT is useful to calculate relative volume and EF. However, to calculate absolute values, we should understand the various factors that affect the result of QGS.     

Age- and gender-specific differences in left ventricular cardiac function and volumes determined by gated SPET

The aim of this study was to determine normative volumetric data and ejection fraction values derived from gated myocardial single-photon emission tomography (SPET) using the commercially available software algorithm QGS (quantitative gated SPET). From a prospective database of 876 consecutive patients who were referred for a 2-day stress-rest technetium-99m tetrofosmin (925 MBq) gated SPET study, 102 patients (43 men, 59 women) with a low (<10%) pre-test likelihood of coronary disease were included (mean age 57.6 years). For stress imaging, a bicycle protocol was used in 79 of the patients and a dipyridamole protocol in 23. Left ventricular ejection fraction (LVEF) and end-diastolic and -systolic volumes (EDV and ESV) were calculated by QGS. EDV and ESV were corrected for body surface area, indicated by EDVi and ESVi. To allow comparison with previous reports using other imaging modalities, men and women were divided into three age groups (<45 years, ₙ years but <65 years and ₭ years). Men showed significantly higher EDVi and ESVi values throughout and lower LVEF values when compared with women in the subgroup ₭ years (P<0.05, ANOVA). Significant negative and positive correlations were found between age and EDVi and ESVi values for both women and men and between LVEF and age in women (Pearson PА.01). LVEF values at bicycle stress were significantly higher than at rest (P=0.000, paired t test), which was the result of a significant decrease in ESV (P=0.003), a phenomenon which did not occur following dipyridamole stress (P=0.409). The data presented suggest that LVEF and EDVi and ESVi as assessed by QGS are strongly gender-specific. Although the physiological significance of these results is uncertain and needs further study, these findings demonstrate that the evaluation of cardiac function and volumes of patients by means of QGS should consider age- and gender-matched normative values.     

Evaluation of cardiac resynchronization therapy in drug-resistant dilated-phase hypertrophic cardiomyopathy by means of Tc-99m sestamibi ECG-gated SPECT

This case describes a 65-year-old male with drug-resistant heart failure. Cardiac resynchronization therapy was performed. We evaluated cardiac function with volume curve differentiation software (VCDiff) from QGS data with Tc-99m sestamibi. Left ventricular parameters during atrial-right ventricular pacing were left ventricular ejection fraction (LVEF) 30%, end-diastolic volume (EDV) 156 ml, end-systolic volume (ESV) 108 ml and peak filling rate 1.12 (EDV/sec). And during dual chamber pacing, those were LVEF 35%, EDV 145 ml and ESV 95 ml and PFR 1.58 (EDV/sec). And during atrial-left ventricular pacing, those were LVEF 36%, EDV 152 ml, ESV 97 ml and peak filling rate (PFR) 1.35 (EDV/sec). Cardiac resynchronization therapy may improve cardiac function as well as dyssynchrony, which could be evaluated non-invasively and accurately by ECG-gated SPECT.     

Assessment of left ventricular function by thallium-201 quantitative gated cardiac SPECT

PURPOSE: Present study was designed to evaluate the accuracy of the measurement of left ventricular volume by quantitative gated SPECT (QGS) software using 201T1 and the effect of cutoff frequency of Butterworth prereconstruction filter on the calculation of volume. METHODS: The RH-2 type cardiac phantom and 20 patients with ischemic heart disease were studied. Left ventricular end-diastolic volume (EDV), end-systolic volume (ESV) and ejection fraction (EF) were calculated by the QGS software using the various frequency of Butterworth filter. These parameters were evaluated by Simpson's method using left ventriculography (LVG). RESULTS: The volume of the phantom calculated by QGS was under-estimated by 14%. In the clinical study, EDV and ESV measured by QGS were smaller than those obtained from LVG by 10%. When the cutoff frequency of Butterworth filter was 0.43 cycles/cm, the values measured by QGS were best correlated with those by LVG (EDV: r = 0.80, p < 0.001; ESV: r = 0.86, p < 0.001; EF: r = 0.80, p < 0.001). CONCLUSION: These data suggest that 201Tl quantitative gated cardiac SPECT can estimate myocardial ischemia and left ventricular function simultaneously.     

Accuracy of ventricular volume and ejection fraction measured by gated myocardial SPECT: comparison of 4 software programs.

Gated myocardial perfusion SPECT has been used to calculate ejection fraction (EF) and end-diastolic volume (EDV) and has correlated well with conventional methods. However, the comparative accuracy of and correlations across various types of gated SPECT software are not well understood. METHODS: Mathematic phantoms of cylindric-hemispheric hybrid models, ranging in volume from 34 to 266 mL, were generated. The clinical cases consisted of 30 patients who participated in a radionuclide angiography and gated blood-pool (GBP) study in addition to undergoing (99m)Tc-sestamibi gated SPECT. Four kinds of software, Quantitative Gated SPECT (QGS), the Emory Cardiac Toolbox (ECT), 4D-MSPECT, and Perfusion and Functional Analysis for Gated SPECT (pFAST) were used to compute EF and EDV, and the results were analyzed by multiple comparisons tests. Patients were classified into 4 groups (i.e., no defect, small defect, large defect, and small heart) so that factors affecting variation could be analyzed. RESULTS: In mathematic models > or = 74 mL, volume error was within +/-15%, whereas for a small volume (34 mL), QGS and 4D-MSPECT underestimated the volume and pFAST overestimated it. The respective intra- and interobserver reproducibility of the results was good for QGS (r = 0.99 and 1.00), ECT (r = 0.98 and 0.98), and 4D-MSPECT (r = 0.98 and 0.98) and fair for pFAST (r = 0.88 and 0.85). The correlation coefficient for EF between gated SPECT and the GBP study was 0.82, 0.78, 0.69, and 0.84 for QGS, ECT, 4D-MSPECT, and pFAST, respectively. The correlation coefficient for EDV between gated SPECT and the GBP study was 0.88, 0.89, 0.85, and 0.90, respectively. Although good correlation was observed among the 4 software packages, QGS, ECT, and 4D-MSPECT overestimated EF in patients with small hearts, and pFAST overestimated the true volume in patients with large perfusion defects. Correlation coefficients among the 4 kinds of software were 0.80-0.95 for EF and 0.89-0.98 for EDV. CONCLUSION: All 4 software programs showed good correlation between EF or EDV and the GBP study. Good correlation was observed also between each pair of quantification methods. However, because each method has unique characteristics that depend on its specific algorithm and thus behaves differently in the various patient subgroups, the methods should not be used interchangeably.     

Reproducibility of Tl-201 and Tc-99m sestamibi gated myocardial perfusion SPECT measurement of myocardial function

BACKGROUND: We compared the reproducibility of thallium 201 and technetium 99m sestamibi (MIBI) gated single photon emission computed tomography (SPECT) measurement of myocardial function using the Germano algorithm (J Nucl Med 1995;36:2138-47). METHODS AND RESULTS: Gated SPECT acquisition was repeated in the same position in 30 patients who received Tl-201 and in 26 who received Tc-99m-MIBI. The quantification of end-diastolic volume (EDV), end-systolic volume (ESV), and ejection fraction (EF) on Tl-201 and Tc-99m-MIBI gated SPECT was processed independently with Cedars-Sinai QGS (Quantitative Gated SPECT) software. The reproducibility of the measurement of ventricular function on Tl-201 gated SPECT was compared with that of Tc-99m-MIBI gated SPECT. Correlation between the 2 measurements for volumes and EF was excellent for the repeated gated SPECT studies of Tl-201 (r = 0.928 to 0.986, P <.05) and Tc-99m-MIBI (r = 0.979 to 0.997, P <.05). However, Bland-Altman analysis revealed the 95% limits of agreement (2 SDs) for volumes and EF were narrower by repeated Tc-99m-MIBI gated SPECT (EDV 14.1 mL, ESV 9.4 mL, EF 5.5%) than by repeated Tl-201 gated SPECT (EDV 24.1 mL, ESV 18.6 mL, EF 10.3%). The root-mean-square values of the coefficient of variation for volumes and EF were smaller by repeated Tc-99m-MIBI gated SPECT (EDV 2.1 mL, ESV 2.7 mL, EF 2.3%) than by repeated Tl-201 gated SPECT (EDV 3.2 mL, ESV 3.5 mL, EF 5.2%). CONCLUSIONS: QGS provides an excellent correlation between repeated gated SPECT with Tl-201 and Tc-99m-MIBI. However, Tc-99m-MIBI provides more reproducible volumes and EF than Tl-201. Tc-99m-MIBI gated SPECT is the preferable method for the clinical monitoring of ventricular function.     

Use of gated 13N-NH3 micro-PET to examine left ventricular function in rats

IntroductionMyocardial perfusion gating techniques offer the possibility of measurement of left ventricular end-systolic (ESV) and end-diastolic volume (EDV) and left ventricular ejection fraction (LVEF) in clinical and preclinical trials. The aim of this study was to evaluate left ventricular volumes (LVV) and LVEF with ¹³N-NH₃ in comparison with the reference ¹⁸F-FDG in different rat models.MethodsIn this study, 18 male Wistar rats, 12 control rats and 6 rats with myocardial infarction (MI) were imaged with micro-PET. The ratswere scanned with gated ¹³N-NH₃ and ¹⁸F-FDG sequentially for the assessment of LVV and LVEF. A validated three-dimensional segmentation algorithm was used to calculate LVV and LVEF.ResultsMean LVEF measured with ¹³N-NH₃ was 45.6±8.9 and 75.3±9.4%, mean ESV was 0.40±0.12 and 0.14±0.11 ml, and mean EDVwas 0.53±16 and 0.75±0.18 ml for MI and control rats, respectively. Moderate to good correlations were observed between values of ¹³N-NH₃ and ¹⁸F-FDG for calculation of ESV [r=0.80, P<.0001, standard error of estimate (SEE)=0.10], EDV (r=0.63, P=.005, SEE=0.14) and LVEF (r=0.84, P<.0001, SEE=9.5). LVEF measured with ¹³N-NH₃ was significantly lower in MI rats in comparison to measurement with ¹⁸F-FDG (45.6±8.9 vs 54.9±9.3 %; P=.04).ConclusionCorrelations were moderate to good for the assessment of ESV, EDV and LVEF between gated ¹³N-NH₃ and ¹⁸F-FDG. LVEF was underestimated with gated ¹³N-NH₃ in rats with myocardial infarction. In healthy rats, LV volumes and LVEF can be measured reproducibly with either approach.