MRI心功能参数对陈旧性心肌梗死左心室重塑的评估价值

目的：观察陈旧性心肌梗死后心室形态和心功能参数的变化,探讨MRI测量心功能参数对心室重塑的评估价值。方法：纳入33例陈旧性心肌梗死患者为病变组,12例健康志愿者为对照组。病变组及对照组成员均行MRI检查。MRI测量参数包括：舒张末期客积（EDV）、收缩末期容积（ESV）、每搏输出量（SV）、左心室射血分数（LVEF）、射血率峰值（PER）、充盈率峰值（PFR）。同时测量梗死心肌面积所占的百分比,以24％为分界值,分为无重塑组（≤24％）和重塑组（〉24％）,分析各组间的心功能参数的差异,进行受试者操作特征（ROC）曲线分析,筛选能独立评估心室重塑的心功能指标。结果：病变组的EDV、ESV、SV均高于对照组,病变组的LVEF、PER和PFR低于对照组。ESV随EDV的增加而增加（P〈0．001）,PER、PFR及LVEF均随EDV的增加而下降（P〈0．05）,而SV与各参数均无相关性。PFR、EDV和ESV的ROC分析曲线下面积分别为0．725、0．741、0．764,分界值分别为2．27EDV／sec、140．23ml和79．12ml（P值分别为0．036、0．021和0．032）。结论：MRI可以从收缩和舒张功能的不同角度全面地评估心功能变化。MRI心功能指标对评估心室重塑有重要作用。PFR、EDV、ESV可以作为独立因子评估心室重塑,其中以PFR的评估效能更高。     

Gated SPECT findings revealing diastolic dysfunction in acute hypothyroidism

PURPOSE: The purpose of this study was to assess left ventricular (LV) function by gated SPECT in acute hypothyroidism. METHODS: Thirty-eight acute hypothyroid patients without any cardiac disease and 40 healthy controls underwent gated SPECT at rest. Fourteen patients had a second examination during thyroxine replacement therapy. Gated SPECT was performed using Tc-99m sestamibi with 16 frames per cardiac cycle. The LV end-diastolic volume (EDV), end-systolic volume (ESV), ejection fraction (EF), peak ejection rate (PER), peak filling rate (PFR), and time to peak filling (TTPF) were measured by quantitative gated SPECT (QGS). Systolic wall thickening/motion was determined in 5 myocardial segments. RESULTS: Hypothyroid patients exhibited a decrease in PFR (222 +/- 52 EDV/s) and prolongation of TTPF (194 +/- 32 msec) as compared with controls (247 +/- 41 EDV/s and 179 +/- 17 msec, respectively; P < 0.05). During thyroxine therapy, the mean values for EDV (74 +/- 21 mL) and PFR (265 +/- 64 EDV/s) increased significantly in 14 follow-up patients (pretreatment values 67 +/- 18 mL and 219 +/- 50 EDV/s, respectively; P < 0.05). A significant difference was detected in the mean TTPF between the thyroxine group and the controls (195 +/- 35 msec vs 179 +/- 17 msec; P < 0.05). No significant differences were found in wall thickening and motion values (P > 0.05). CONCLUSION: Gated SPECT findings revealed diastolic dysfunction as indicated by a decrease in PFR and a prolongation in TTPF in patients with acute hypothyroidism.     

Left ventricular systolic/diastolic function evaluated by quantitative ECG-gated SPECT: comparison with echocardiography and plasma BNP analysis

OBJECTIVE: The aim of this study was to evaluate the left ventricular (LV) functional parameters calculated using quantitative electrocardiography (ECG)-gated myocardial perfusion single photon emission computed tomography (QGS). In addition to LV systolic parameters, diastolic parameters were compared with those by ultrasound echocardiography (UCG) and also with plasma B-type natriuretic peptide (BNP) concentrations. METHODS: We examined 46 patients with various forms of heart disease. By the QGS data with 16 framing data acquisition using technetium (Tc)-99m methoxyisobutylisonitrile (MIBI) perfusion, we calculated the following parameters: LV end-diastolic volume (EDV), end-systolic volume (ESV), ejection fraction (EF), peak filling rate (PFR), filling rate during the first third of the filling time (1/3FR) and first third filling fraction (1/3FF). By UCG, we measured mitral early to atrial (E/A) wave velocity ratio and pulmonary venous inflow systolic/diastolic (S/D) ratio as diastolic functional parameters. Plasma BNP concentrations were also measured. RESULTS: There was a significant correlation between LVEDV, ESV and EF measured by QGS and UCG (EDV, r = 0.71, p < 0.001; ESV, r = 0.82, p < 0.001; EF, r = 0.75, p < 0.001). The PFR, 1/3FR and 1/3FF obtained by QGS correlated positively with E/A ratio (PFR, r = 0.54, p < 0.001; 1/3FR, r = 0.61, p < 0.001; 1/3FF, r = 0.42, p < 0.01) and negatively with S/D ratio (PFR, r = -0.40, p < 0.01; 1/3FR, r = -0.38, p < 0.05; 1/3FF, r = -0.39, p < 0.01) obtained by UCG. Plasma BNP concentrations in EF < 50% patients were greater than those in EF > or = 50% patients (335.2 +/- 60.2 vs. 101.2 +/- 41.3 pg/ml, p < 0.01, both n = 17). Plasma BNP levels were also compared between higher and lower 1/3FF patients matched for LVEF. Plasma BNP concentrations in 1/3FF < 35% patients were significantly greater than those in 1/3FF > or = 35% patients (312.9 +/- 62.5 vs. 120.5 +/- 32.8 pg/ml, p < 0.05, both n = 14). CONCLUSIONS: The degree of LV systolic and diastolic dysfunctions evaluated by QGS correlated with that by UCG or BNP. The QGS functional parameters offer useful information regarding cardiac failure.     

Assessment of global left and right ventricular function using dual-source computed tomography (DSCT) in comparison to MRI: an experimental study in a porcine model

OBJECTIVE: We sought to evaluate the ability of retrospectively ECG-gated dual-source computed tomography (DSCT) to assess left (LV) and right ventricular (RV) functional parameters in comparison to 1.5 T magnetic resonance imaging (MRI). MATERIALS AND METHODS: Ten domestic pigs (60 kg) underwent both contrast-enhanced cardiac DSCT and cardiac MRI using standardized examination protocols under general anesthesia. From manually drawn endocardial and epicardial contours, LV and RV end-systolic (ESV) and end-diastolic volume (EDV), stroke volume (SV), ejection fraction (EF), myocardial mass (MM), peak filling rate (PFR), peak ejection rate (PER), time to peak ejection (TPE), and time to peak filling (TPF) were calculated by means of dedicated analysis software. LV and RV functional parameters were analyzed using Bland-Altman plots, Student t test, and Pearson's correlation coefficient. RESULTS: Both left and right ESV and EDV, SV and EF determined with DSCT correlated well with MR imaging results (left, r = 0.98/0.92/0.82/0.98; right, r = 0.90/0.94/0.96/0.94). PER, PFR, TPE, TPF, and MM showed only a moderate to low correlation (left, r = 0.67/0.37/0.23/0.35/0.57; right, r = 0.78/0.69/0.12/0.11/0.44). PER and PFR were significantly underestimated by DSCT when compared with MRI. CONCLUSIONS: Retrospectively ECG-gated DSCT correctly depicts end-systole and can accurately determine LV and RV volumes, SV, and EF in comparison to MRI. DSCT showed a significant underestimation of PER and PFR in comparison to MRI.     

Ventricular systolic and diastolic rate indices in patients with either normal or low resting left ventricular ejection fraction

To investigate the potential uses of right and left ventricular systolic and diastolic rate indices in identifying patients with ischaemic heart disease (IHD), gated blood-pool imaging was performed for 19 normal subjects (group 1) and 56 patients, of whom 31 had resting LVEF greater than or equal to 50% (group 2) and 25 had resting LVEF less than or equal to 50 (group 3). The peak ejection rate (PER) and peak filling rate (PFR), their timing and the mean filling rate (MFR) were derived from the time-activity curves analysis. Group 2 patients had significantly reduced LV PER and PFR (3.00 +/- 0.58 EDV/s, p less than 0.005, 2.29 +/- 0.54 EDV/s, p less than 0.0009) as compared to normal (3.90 +/- 0.70 EDV/s and 3.35 +/- 0.80 EDV/s respectively). Patients with profoundly depressed LVEF had significantly low PER and PFR (1.96 +/- 0.50 EDV/s, 1.46 +/- 0.27 EDV/s respectively). However, there was considerable overlap in values between groups. Therefore, we conclude that there is no single parameter more sensitive than LVEF in identifying IHD patients with normal LVEF at rest.     

Differential systolic and diastolic effects of β-adrenergic stimulation in patients with severe left ventricular dysfunction: A radionuclide ventriculographic study

BACKGROUND: An attenuated inotropic response to beta-adrenergic stimulation has been documented in patients with severely depressed left ventricular (LV) function. Scant data exist regarding the effect of beta-adrenergic stimulation on LV diastolic function in human beings. Our objective was to evaluate the effect of dobutamine infusion on LV systolic and diastolic function in patients with severe ventricular dysfunction. METHODS AND RESULTS: We studied 26 patients (60 +/- 9 years) in stable condition with healed myocardial infarction and LV ejection fraction (EF) less than 35% by radionuclide ventriculography. LVEF, volumes, peak ejection rate (PER), peak filling rate (PFR), and peak systolic pressure-to-end-systolic volume ratio were calculated at the infusion rate of 5 and 10 gamma x kg(-1) x min(-1). At 5 gamma x kg(-1) x min(-1), no changes were observed in heart rate (75 +/- 16 beats/min vs 75 +/- 15 beats/min at rest), LVEF (23% +/- 8% vs 22% +/- 7%), and PER (1.40 +/- 0.48 end-diastolic volume per second [EDV/s] vs 1.30 +/- 0.48 EDV/s); however, a significant increase in PFR was observed (1.11 +/- 0.36 EDV/s vs 0.86 +/- 0.30 EDV/s, P < .01). At 10 gamma x kg(-1) x min(-1), an increase in LVEF (25% +/- 10%, P < .01) and PER (1.60 +/- 0.57 EDV/s, P < .01) was observed; PFR (1.25 +/- 0.36 EDV/s, P < .05) also increased, whereas heart rate (78 +/- 18 beats/min) was unchanged. No significant changes in LV volumes or in indices of LV contraction synchronicity were observed during infusion. Finally, the peak systolic pressure-to-end-systolic volume ratio was unchanged at 5 gamma x kg(-1) x min(-1) and significantly increased at 10 gamma x kg(-1) x min(-1). CONCLUSIONS: In stable patients with ischemic heart disease and severe LV dysfunction, beta-adrenergic stimulation may still induce a positive lusitropic response, despite attenuated inotropic and chronotropic responses; moreover, the effects on diastolic function occur earlier than those on systolic function.     

The agreement of left ventricular function parameters between 99mTc-tetrofosmin gated myocardial SPECT and gated myocardial MRI

Objective

The aim is to compare and evaluate the agreement of quantification of left ventricular functional parameters obtained by two different methods, ^99mTc-tetrofosmin gated myocardial perfusion SPECT (MPS) and cardiac magnetic resonance imaging (CMR).

Methods

Ten healthy male volunteers participated. Gated MPS data were acquired using 32 frames, which were also combined into 16- and 8-frame data set for the investigation. Gated CMR data were acquired using 8, 16 and 32-frame for the different sets. All examinations were conducted in resting and at exercise conditions. Quantitative measurements of end-diastolic volume (EDV), end-systolic volume (ESV), left ventricular ejection fraction (LVEF), peak ejection rate (PER), peak filling rate (PFR) and time to peak filling (TTPF) were done for each study, respectively. Finally, we evaluated the concordance of parameters between gated MPS and gated CMR by % difference and Bland?CAltman plot analysis.

Results

LVEF showed favorable concordance in both rest and exercise conditions (% differences were around 10%). PER, PFR and TTPF also showed good concordances in rest conditions, under 32-frame gated collections particularly (% differences were around 10%). In exercise conditions, although the concordances were relatively good, certain variances were noted (% differences were around 20?C25%). Regarding left ventricular volumes, the concordance were worse in both conditions (% differences were around 30?C40%).

Conclusions

In quantifying of left ventricular function parameter, gated CMR provides similar quantitative values comparing with gated MPS except for ventricular volumes in rest conditions. In contrast, there were certain variations except for LVEF in exercised examinations. When we follow patients by the same cardiac parameters with CMR and MPS, using parameters across the two modalities proved to be possible under rest condition. However, it is limited at exercise condition.     

Comparison of left ventricular functional parameters obtained from three different commercial automated software cardiac quantification program packages and their intraobserver reproducibility

Objective  

ECG-gated myocardial perfusion scintigraphy (MPS) can be used to determine several cardiac functional parameters (e.g., left ventricular ejection fraction (LVEF), end-diastolic volume (EDV), and end-systolic volume (ESV)). In this study, we aimed to compare these cardiac functional parameters calculated by the following cardiac quantification programs: Emory Cardiac Toolbox (ECTb), Quantitative Gated SPECT (QGS), and Myometrix. We also evaluated reproducibility of the cardiac programs.     

99Tcm-N-NOET负荷和延迟门控心肌灌注显像对高血压患者的临床价值

Objective To investigate clinical significance of the 99Tcm-bis (N-ethoxy-N-ethyl-dithiocarbamato) nitridotechnetium(99Tcm-N-NOET) exercise and delayed myocardial perfusion imaging (MPI) in hypertensive patients. Methods Sixty patients with hypertension and 19 normal subjects were carried out 99Tcm-N-NOET exercise and delayed MPI, and analyzed the results of MPI, exercise electrocardiography (ECG), cardiac function parameters end-diastolic volume(EDV), end-systolic volume(ESV), left ventricular ejection fraction(LVEF), △ LVEF (LV EF exercis-LVEF delay) and coronary angiography(CAG). Results ① Sixty patients with hypertension, 22 cases(36.7%)of exercise ECG were abnormal, 16 cases (26.7%)were the chest tightness in exercise, 13 cases (21.7%) were blood pressure excessive reaction in exercise; control group, 2 cases (10.5%) of exercise ECG were abnormal, 1 case (5.3%, 1/19) was chest tightness in exercise,no per-son was blood pressure response in excessive. ②The positive rate of myocardial perfusion in hyper tensive group was significantly higher than the control group (31.75％ vs.5.30％, P<0.05). ③Cardial function parameters in hypertension group [exercise EDV =(79.75 ±29.10)ml, ESV =(28.82 ± 15.73)ml, LVEF =(65.78 ±1.27)%; delay EDV=(81.42±3.47)ml, ESV=(30.62±2.05)ml, LVEF=(64.20±9.70)%] and control group[exercise EDV=(79.63 ±21.65)ml, ESV=(27.37±10.71)ml, LVEF=(66.42±1.55)%; delay EDV=(82.89±4.96)ml,ESV=(31.42±3.06)ml, LVEF=(63.16 ±7.54)%] were no statistical difference(exercise EDV: t=0.161, ESV: t=0.112, LVEF: t=0.261; delay EDV: t=0.276, ESV: t=0.197, LVEF: t=0.184, P>0.05), △ LVEF<0%, 28 cases (46.7%) in hypertension group, 4 cases (21.1%) in control group, χ2=3.929, P<0.05; 11 cases (57.9%) in MPI positive group, 12 cases (29.3％) in MPI negative group, χ2=4.501, P<0.05. ④Nineteen hypertension underwent CAG, 11 cases were abnormal, 8 cases were normal. MPI results: 9 cases were ischemia, 10 cases were normal, and they were no statistical difference (χ2=0.25, P>0.05). The sensitivity,specificity and accuracy of 99Tcm-N-NOET MPI were 72.7％, 87.5％ and 78.9％. Conclusions ①99Tcm-N-NOET exercise and delayed MPI can diagnose whether hypertension patients with myocardial ischemia or not. ② △ LVEF of hypertensive patients reduced, △ LVEF is lower in hypertensive patients of MPI-positive.     

Exercise-induced stunning continues for at least one hour: evaluation with quantitative gated single-photon emission tomography

To elucidate the after-effect of exercise on left ventricular (LV) function, end-diastolic volume (EDV), end-systolic volume (ESV) and ejection fraction (LVEF) were evaluated at 1 h after exercise and at rest by technetium-99m tetrofosmin gated myocardial single-photon emission tomography (SPET) using an automated program in 53 subjects. The subjects were grouped as follows: normal scan (n = 16), ischaemia (n = 19) and infarction (n = 18), based on the interpretation of perfusion images. Postexercise LVEF did not differ from resting LVEF in the groups with normal scan and infarction. In patients with ischaemia, postexercise EDV (90+/-17 ml, mean +/-SD) and ESV (44+/-15 ml) were significantly higher than EDV (84+/-15 ml, P = 0.001) and ESV (36+/-14 ml, P<0.0005) at rest. LVEF was significantly depressed 1 h after exercise (53%+/-9% vs 58%+/-9%, P<0.0001). In ischaemic patients with depressed postexercise LVEF, LVEF difference between rest and postexercise showed a significant correlation with the sum of defect scores, which were reversible from exercise to rest perfusion images (r = 0.92, P<0.0001). These results indicate that exercise-induced LV dysfunction (myocardial stunning) continues for at least 1 h in ischaemic patients and that the extent of LVEF depression is determined by the severity of ischaemia.     

Cardiac resynchronization therapy evaluated by myocardial scintigraphy with <Superscript>99m</Superscript>Tc-MIBI: changes in left ventricular uptake,dyssynchrony, and function

Purpose   ^99mTc-MIBI gated myocardial scintigraphy (GMS) evaluates myocyte integrity and perfusion, left ventricular (LV) dyssynchrony and function. Cardiac resynchronization therapy (CRT) may improve the clinical symptoms of heart failure (HF), but its benefits for LV function are less pronounced. We assessed whether changes in myocardial ^99mTc-MIBI uptake after CRT are related to improvement in clinical symptoms, LV synchrony and performance, and whether GMS adds information for patient selection for CRT. Methods  A group of 30 patients with severe HF were prospectively studied before and 3 months after CRT. Variables analysed were HF functional class, QRS duration, LV ejection fraction (LVEF) by echocardiography, myocardial ^99mTc-MIBI uptake, LV end-diastolic volume (EDV) and end-systolic volume (ESV), phase analysis LV dyssynchrony indices, and regional motion by GMS. After CRT, patients were divided into two groups according to improvement in LVEF: group 1 (12 patients) with increase in LVEF of 5 or more points, and group 2 (18 patients) without a significant increase. Results  After CRT, both groups showed a significant improvement in HF functional class, reduced QRS width and increased septal wall ^99mTc-MIBI uptake. Only group 1 showed favourable changes in EDV, ESV, LV dyssynchrony indices, and regional motion. Before CRT, EDV, and ESV were lower in group 1 than in group 2. Anterior and inferior wall ^99mTc-MIBI uptakes were higher in group 1 than in group 2 (p<0.05). EDV was the only independent predictor of an increase in LVEF (p=0.01). The optimal EDV cut-off point was 315 ml (sensitivity 89%, specificity 94%). Conclusion  The evaluation of EDV by GMS added information on patient selection for CRT. After CRT, LVEF increase occurred in hearts less dilated and with more normal ^99mTc-MIBI uptake.     

Assessment of left ventricular function by gated myocardial perfusion and gated blood-pool SPECT: Can we use the same reference database?

The purpose of this study was to compare left ventricular (LV) volume and ejection fraction (LVEF) measurements obtained with electrocardiographic gated single-photon emission computed tomographic (SPECT) myocardial perfusion imaging (GS-MPI) with those obtained with gated SPECT cardiac blood-pool imaging (GS-pool). Fifteen patients underwent GS-MPI with technetium-99m-tetrofosmin and GS-pool with technetium-99m-erythrocyte, within a mean interval of 8 +/- 3 days. Eight patients had suspected dilated cardiomyopathy and seven patients had angiographically significant coronary artery disease. End-diastolic volume (EDV), end-systolic volume (ESV) and LVEF measurements were estimated from GS-MPI images by means of Cedars-Sinai automatic quantitative program and from GS-pool images by the threshold technique. Mean differences between GS-MPI and GS-pool in EDV, ESV and LVEF measurements were -2.8 +/- 10.5 ml [95% confidence interval (CI): -8.6 +/- 3.0 ml], 2.6 +/- 7.3 ml (CI: -1.4 +/- 6.6 ml) and -2.3 +/- 5.1% (CI: -5.1 +/- 0.6%), respectively. No significant difference in the mean differences from 0 was found for EDV, ESV or LVEF measurements. Bland-Altman plots revealed no trend over the measured LV volumes and LVEF. For all parameters, regression lines approximated lines of identity. The excellent agreement between GS-MPI and GS-pool measurements suggests that, for estimation of LV volumes and LVEF, these two techniques may be used interchangeably and measurements by one method can serve as a reference for the other.     

Prone versus supine patient positioning during gated 99mTc-sestamibi SPECT: effect on left ventricular volumes, ejection fraction, and heart rate.

Gated myocardial perfusion SPECT allows assessment of left ventricular end-diastolic volume (EDV), left ventricular end-systolic volume (ESV), left ventricular stroke volume (SV), and left ventricular ejection fraction (LVEF). Acquiring images with the patient both prone and supine is an approved method of identifying and reducing artifacts. Yet prone positioning alters physiologic conditions. This study investigated how prone versus supine patient positioning during gated SPECT affects EDV, ESV, SV, LVEF, and heart rate. METHODS: Forty-eight patients scheduled for routine myocardial perfusion imaging were examined with gated (99m)Tc-sestamibi SPECT (at rest) while positioned prone and supine (consecutively, in random order). All parameters for both acquisitions were calculated using the commercially available QGS algorithm. RESULTS: Whereas EDV and SV were significantly lower (P < 0.0004) for prone acquisitions (EDV, 110.5 +/- 39.1 mL; SV, 55.9 +/- 13.3 mL) than for supine acquisitions (EDV, 116.9 +/- 36.2 mL; SV, 61.0 +/- 14.5 mL), ESV and LVEF did not differ significantly. Heart rate was significantly higher (P < 0.0001) during prone acquisitions (69.1 +/- 10.5 min(-1)) than during supine acquisitions (66.5 +/- 10.0 min(-1)). CONCLUSION: The observed position-dependent effect on EDV, SV, and heart rate might be explained by decreased arterial filling and increased sympathetic nerve activity. Hence, supine reference data should not be used to classify the results of prone acquisitions.     

Left ventricular ejection fraction and volumes on rest gated 201Tl perfusion SPECT: comparison with two-dimensional echocardiography

BACKGROUND: Rest gated 201Tl images are considered to be of poor count statistics due to lower energy and low photon flux of 201Tl in addition to increased attenuation and low dose that can be administered. We compared the left ventricular ejection fraction (LVEF), end diastolic (EDV) and end systolic volume (ESV) obtained on 4 h gated rest 201Tl myocardial perfusion single photon emission computed tomography (SPECT) with those obtained by two-dimensional echocardiography (2-D ECHO) in patients with known or suspected coronary artery disease (CAD). METHODS: Eighty-two consecutive patients who underwent gated 201Tl stress-rest myocardial perfusion SPECT and 2-D ECHO were studied. The gated thallium images were processed with Siemens e-soft autocardiac processor and LVEF, EDV and ESV were evaluated using Emory Cardiac Toolbox. The same parameters were also assessed on the 2-D ECHO using the modified Simpson method for comparison. RESULTS: Out of 82 rest gated images, one study was excluded because of poor count statistics. In 81 (99%) patients there was good linear correlation with 2-D ECHO values and rest gated 201Tl SPECT images for EDV, ESV and LVEF. Pearson's correlation co-efficient (r value) for EDV, ESV and LVEF between the two methods was 0.78, 0.79 and 0.88, respectively. A Bland-Altman plot showed close agreement with LVEF but not for EDV and ESV. CONCLUSION: These results suggest that the 4 h rest gated 201Tl study gives a reliable value for the LVEF compared to 2-D ECHO and can be used in routine clinical practice.     

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.     

Evaluation of the left ventricular hemodynamic function and myocardial perfusion by gated single photon emission tomography, in patients with type 1 diabetes mellitus; prodromal signs of cardiovascular disease after four years

The aim of this study was to assess the changes in hemodynamic function and myocardial perfusion of the left ventricle occurring in patients with type 1 diabetes mellitus (DM1) 47-49 months after the first assessment. We have studied 20 asymptomatic patients, five females and 15 males, aged 22-46 y. The patients were under intensive insulin treatment and had normal electrocardiogram (ECG) at rest. In all patients gated single photon emission tomography (GSPET) was performed at rest and after exercise (examination I). After 47-49 months this test was repeated (examination II). GSPET was performed 60 min after the intravenous injection of 740 MBq of technetium-99m 2-methoxy-isobutyl-isonitrile ((99m)Tc-MIBI), using a dual-headed gamma-camera. Left ventricular ejection fraction (LVEF), end diastolic volume (EDV) and end systolic volume (ESV) were calculated using quantitative GSPET (QGS). The intensity of perfusion defects was also evaluated based on a four degree QGS scale. Our results were as follows: a) In examination I, performed at rest: LVEF was 56.1%+/-7.5%, EDV 96.9+/-25.8 ml and ESV 42.6+/-16.3 ml. b) In examination I at stress: LVEF was 57.2%+/-7.5%, EDV 94.1+/-24.0 ml and ESV 40.5+/-15.5. c) In examination II performed at rest: LVEF was 58.1%+/-6.5%, EDV 112.1+/-26.1 ml and ESV 46.6+/-14.9 ml and d) In examination II at stress: LVEF 57.8%+/-5.6%, EDV 107.9+/-27.4 ml and ESV 44.9+/-14.4 ml. Significant differences were found between examinations I and II, regarding: a) EDV at rest (P<0.001) and at stress (P<0.001) and b) ESV at rest (P<0.05) and at stress (P<0.005). Correlation analysis revealed significant correlation between LVEF at rest and at stress both in examination I (r=0.83; P<0.001) and also in examination II (r=-0.897; P<0.001). Intensity of myocardial perfusion defects in examination I at rest and at stress was: 1.68+/-0.5 and 2.2+/-0.6 degrees respectively. Intensity of myocardial perfusion defects in examination II at rest and at stress was: 1.75+/-0.4 and 2.2+/-0.5 respectively. No significant differences in the intensity of these perfusion defects were found. EDV both at rest and at stress was significantly higher in examination II as compared with the examination I study. Similar, but less pronounced changes of ESV were found. This study confirms other authors' observations on LV, EDV and LV, ESV and also that the percentage of asymptomatic DM1 patients having silent myocardial ischemia is high as was in all our patients. Nevertheless, in the current literature, we were unable to find a study similar to the present one, comparing basal and after four years LV functional GSPET data, in asymptomatic DM1 patients. In conclusion, myocardial perfusion GSPET was useful as a screening test in DM1 patients in showing four years after the basal study, prodromal signs of cardiovascular disease, especially increase of left ventricular volumes and silent myocardial ischemia, in these patients. Our research on the above protocol is being continued.     

Assessment of diastolic function using 16-frame 99mTc-sestamibi gated myocardial perfusion SPECT: normal values.

The purposes of this study were (a) to assess the feasibility of diastolic function (DFx) evaluation using standard 16-frame postexercise gated (99m)Tc-sestamibi myocardial perfusion SPECT (MPS), (b) to determine the relationship of the 2 common DFx parameters, peak filling rate (PFR) and time to peak filling (TTPF), to clinical and systolic function (SFx) variables in patients with normal myocardial perfusion and SFx, and (c) to derive and validate normal limits. METHODS: Ninety patients (71 men; age, 30-79 y) with normal exercise gated MPS were studied. None had hypertension, diabetes, rest electrocardiogram abnormality, or known cardiac disease. All patients reached > or = 85% of maximum predicted heart rate (HR). The population was randomized into derivation (n = 50) and validation (n = 40) groups. Univariable and multivariable approaches were deployed to assess the influence of clinical and functional variables on DFx parameters. RESULTS: PFR and TTPF were assessed in all patients. Mean values of PFR and TTPF in the whole study population were 2.62 +/- 0.46 end-diastolic volumes per second (EDV/s) and 164.6 +/- 21.7 ms, respectively. By applying a 2-SD cutoff to the mean values in the derivation group, the threshold for abnormal PFR and the threshold for abnormal TTPF were < 1.71 EDV/s and > 216.7 ms, respectively. The normalcy rates in the validation group for PFR and TTPF were both 100%. The PFR showed weak but significant correlations with age, EDV, end-systolic volume, left ventricular ejection fraction (LVEF), and poststress HR. However, TTPF did not correlate with these parameters. Final normal thresholds determined from the combined populations were PFR = 1.70 EDV/s and TTPF = 208 ms. Multivariable analysis showed that age, sex, LVEF, and HR are strong predictors for PFR, whereas TTPF was not influenced by any clinical or SFx variable. CONCLUSION: With a new algorithm in QGS, assessment of LV DFx is feasible using 16-frame gated MPS even without bad-beat rejection, resulting in normal limits similar to those reported with gated blood-pool studies. However, due to the dependency of PFR on SFx parameters, sex, HR, and age, TTPF appears to be a stable and more useful parameter with this approach. The clinical usefulness of these findings requires further study.     

Ischaemic related transitory left ventricular dysfunction in 201Tl gated SPECT

AIM: To report our data concerning the changes in post-stress and at-rest left ventricular ejection fraction and ventricular volumes in patients with thallium gated SPECT. METHODS: Post-stress and at-rest thallium gated SPECT was performed in 629 consecutive patients; left ventricular ejection fraction (LVEF), left ventricular volumes and quantitative perfusion data were obtained. Transitory left ventricular dysfunction was diagnosed when post-stress LVEF did not increase at least 5% from LVEF at-rest. RESULTS: In all patients post-stress LVEF was 64%+/-17 while at-rest LVEF was 66%+/-15 (P=0.6). Post-stress end diastolic volume (EDV) was 142 ml+/-7, at-rest EDV was 141 ml+/-92 (P=0.57), post-stress end systolic volume (ESV) was 54 ml+/-51 and at-rest ESV was 56 ml+/-59 (P=0.38). Data from the perfusion study were used to divide patients into three groups: normal patients (group I), patients with total or partially reversible defects (group II) and patients with fixed defects (group III). In group I and group III patients LVEF at-rest was lower than post-exercise (LVEF 75%+/-11 vs 81%+/-10 (P<0.001) and 57%+/-16 vs 60%+/-18 (P=0.025)), respectively. Patients in group II had a higher at-rest LVEF than post-exercise (LVEF 66%+/-14 vs 64%+/-16 (P=0.003)). While the left ventriuclar volumes in group I and III patients decreased with exercise, group II patients had increased post-stress ESV. CONCLUSIONS: Post-stress and at-rest LVEF are similar when all patients are considered but significant differences appear when patients are divided according to the results of the perfusion study. Normal and fixed defect patients have increased post-exercise LVEF. Patients with reversible defects have decreased LVEF, which is largely due to an increased ESV. Transitory left ventricular dysfunction is related to the presence of reversibility and may benefit from revascularization.     

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.     

Comparison of radionuclide ventriculography using SPECT and planar techniques in different cardiac conditions

PURPOSE: Accurate assessment of ventricular function is required to optimize therapeutic management of cardiac diseases. The aim of this study was to correlate planar equilibrium multigated acquisition (MUGA) with tomographic ventriculography (SPECT) in patients with diverse volumes and wall motion abnormalities. METHODS: Eighty-three studies in 80 patients (56+/-14 years; 56% women) were classified according to ventricular dilation, wall motion abnormalities and systolic dysfunction. Left and right ventricular ejection fraction (LVEF and RVEF) and end-diastolic and end-systolic left ventricular volumes (EDV and ESV) were obtained using a commercial QBS program for SPECT. On planar acquisition, LVEF and RVEF were obtained using standard techniques and volumes were determined using the count-based method, without blood sampling. RESULTS: A. Total group: With the planar method, LVEF was 44+/-17%, RVEF 42+/-13%, left EDV 147+/-97 ml (range 31-487 ml) and left ESV 93+/-85 ml (range 15-423 ml); with SPECT the corresponding values were 40+/-20%, 49+/-16%,131+/-95 ml and 91+/-89 ml, respectively (p=NS for all but RVEF). Linear correlation was 0.845 for LVEF, 0.688 for RVEF, 0.927 for left EDV and 0.94 for left ESV, with good intra-class correlation. B. Subgroups: Global and intra-class correlations between planar imaging and SPECT were high for volumes, RVEF and LVEF in all subgroups, except in patients with normal wall motion and function, who showed smaller volumes with SPECT. The group with diffuse wall motion abnormalities had a lower EDV on SPECT. In the abnormal left ventricle, RVEF was higher with SPECT. CONCLUSION: Good correlation and agreement exist between SPECT and planar MUGA with respect to LVEF and left ventricular volumes. SPECT is useful in patients with functional abnormalities, but less reliable in those with normal small cavities. A combined technique is still necessary, and RVEF should be interpreted cautiously.