Left ventricular diastolic dyssynchrony assessed with phase analysis of gated myocardial perfusion SPECT: a comparison with tissue Doppler imaging

Purpose

The aim of the current study was to evaluate the feasibility of phase analysis on gated myocardial perfusion SPECT (GMPS) for the assessment of left ventricular (LV) diastolic dyssynchrony in a head-to-head comparison with tissue Doppler imaging (TDI).

Methods

The population consisted of patients with end-stage heart failure of New York Heart Association functional class III or IV with a reduced LV ejection fraction of ??35%. LV diastolic dyssynchrony was calculated using TDI as the maximal time delay between early peak diastolic velocities of two opposing left ventricle walls (diastolic mechanical delay). Significant LV diastolic dyssynchrony was defined as a diastolic mechanical delay of >55?ms on TDI. Furthermore, phase analysis on GMPS was performed to evaluate LV diastolic dyssynchrony; diastolic phase standard deviation (SD) and histogram bandwidth (HBW) were used as markers of LV diastolic dyssynchrony.

Results

A total of 150 patients (114 men, mean age 66.0?±?10.4?years) with end-stage heart failure were enrolled. Both diastolic phase SD (r?=?0.81, p?r?=?0.75, p?55?ms) showed significantly larger diastolic phase SD (68.1?±?13.4° vs. 40.7?±?14.0°, p?p?Conclusion Phase analysis on GMPS showed good correlations with TDI for the assessment of LV diastolic dyssynchrony.     

Left ventricular dyssynchrony assessed by two three-dimensional imaging modalities: phase analysis of gated myocardial perfusion SPECT and tri-plane tissue Doppler imaging

Purpose To compare left ventricular (LV) dyssynchrony assessment by phase analysis from gated myocardial perfusion SPECT (GMPS) with LV dyssynchrony assessment by tri-plane tissue Doppler imaging (TDI). Baseline LV dyssynchrony assessed with standard deviation (SD) of time-to-peak systolic velocity of 12 LV segments (Ts-SD) with TDI has proven to be a powerful predictor of response to CRT. Information on LV dyssynchrony can also be provided by GMPS with phase analysis of regional LV maximal count changes throughout the cardiac cycle. Methods Forty heart failure patients, referred for evaluation of potential eligibility for CRT, underwent both 3D echocardiography, with tri-plane TDI, and resting GMPS. From tri-plane TDI, Ts-SD was used as a validated parameter of LV dyssynchrony and compared with different indices (histogram bandwidth, phase SD, histogram skewness and kurtosis) derived from phase analysis of GMPS. Results Histogram bandwidth and phase SD showed good correlation with Ts-SD (r=0.77 and r=0.74, p<0.0001, respectively). Patients with substantial LV dyssynchrony assessed with tri-plane TDI (Ts-SD ≥33 ms) had also significantly higher values of histogram bandwidth and phase SD. Conclusions The results of this study support the use of phase analysis by GMPS to evaluate LV dyssynchrony. Histogram bandwidth and phase SD showed the best correlation with Ts-SD assessed with tri-plane TDI and appeared the most optimal variables for assessment of LV dyssynchrony with GMPS.     

门控心肌灌注断层显像相位分析评价健康人左室心肌收缩同步性

目的 应用美国Cedars-Sinai定量门控心肌断层显像(QGS)软件的相位分析技术定量分析健康人左室心肌收缩同步性.方法 对74名健康人[男41名,女33名,平均年龄(60±13)岁]进行运动-静息99Tcm-MIBI G-MPI.应用QGS软件对重建后的静息图像进行自动分析,获得左室心肌收缩同步性参数:相位直方图带宽(BW)和相位标准差(SD),比较不同性别及年龄组(＜60岁组,36名;≥60岁组,38名)间左室心肌收缩同步性的差别.测量左室17个节段的起始相位角度,确定左室心肌最早收缩部位,简单随机抽样选择40名受检者评价QGS软件相位分析技术在同一操作者和不同操作者间的重复性.数据分析采用两样本t检验和直线相关分析.结果 74名受检者左室BW和SD值分别为(37.22±11.71)°和(11.84±5.39)°.男性和女性BW及SD值差异均无统计学意义[BW:(36.00±9.70)°和(38.73±13.84)°;SD:(11.88±5.56)°和(11.79±5.26)°;t=0.96和-0.07,均P＞0.05).年龄≥60岁组较年龄＜60岁组BW宽[(39.95±12.65)°和(34.33±10.00)°;t=-2.11,P＜0.05];但2年龄组间SD差异无统计学意义[(11.18±4.31)°和(12.54±6.33)°;t=1.08,P＞0.05].74名受检者中,54名(73％)左室心肌收缩从基底部向心尖部扩散,仅20名(27％)由心尖部向基底部扩散.同一操作者2次操作及2名操作者间相位分析结果均相关(r=0.867～0.906,均P＜0.001).结论 健康人左室心肌收缩同步性良好,不同性别间无明显差异,年龄＜60岁者心肌收缩同步性较≥60岁者更好.QGS心脏相位分析软件是可定量评价左室心肌收缩同步性的工具,且重复性好.     

Left-ventricular systolic and diastolic dyssynchrony as assessed by multi-harmonic phase analysis of gated SPECT myocardial perfusion imaging in patients with end-stage renal disease and normal LVEF

Background

The purpose of this study was to develop a multi-harmonic phase analysis method to measure diastolic dyssynchrony from conventional gated SPECT myocardial perfusion imaging (MPI) data and to compare it with systolic dyssynchrony in normal subjects and in patients with end-stage renal disease (ESRD) and normal left-ventricular ejection fraction (LVEF).

Methods

121 consecutive patients with ESRD and normal LVEF and 30 consecutive normal controls were enrolled. Diastolic dyssynchrony parameters were calculated using 3-harmonic phase analysis. Systolic dyssynchrony parameters were calculated using the established 1-harmonic phase analysis.

Results

The systolic and diastolic dyssynchrony parameters were correlated, but significantly different in both control and ESRD groups, indicating they were physiologically related but measured different LV mechanisms. The systolic and diastolic dyssynchrony parameters were each significantly different between the control and the ESRD groups. Significant systolic and diastolic dyssynchrony were found in 47% and 65% of the entire ESRD group.

Conclusion

Multi-harmonic phase analysis has been developed to assess diastolic dyssynchrony, which measured a new LV mechanism of regional function from gated SPECT MPI and showed a significantly higher prevalence rate than systolic dyssynchrony in patients with ESRD and normal LVEF.     

LV dyssynchrony as assessed by phase analysis of gated SPECT myocardial perfusion imaging in patients with Wolff-Parkinson-White syndrome

Purpose

The purpose of this study was to evaluate left ventricular (LV) mechanical dyssynchrony in patients with Wolff-Parkinson-White (WPW) syndrome pre- and post-radiofrequency catheter ablation (RFA) using phase analysis of gated single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI).

Methods

Forty-five WPW patients were enrolled and had gated SPECT MPI pre- and 2–3?days post-RFA. Electrophysiological study (EPS) was used to locate accessory pathways (APs) and categorize the patients according to the AP locations (septal, left and right free wall). Electrocardiography (ECG) was performed pre- and post-RFA to confirm successful elimination of the APs. Phase analysis of gated SPECT MPI was used to assess LV dyssynchrony pre- and post-RFA.

Results

Among the 45 patients, 3 had gating errors, and thus 42 had SPECT phase analysis. Twenty-two patients (52.4?%) had baseline LV dyssynchrony. Baseline LV dyssynchrony was more prominent in the patients with septal APs than in the patients with left or right APs (p?p?Conclusion Phase analysis of gated SPECT MPI demonstrated that LV mechanical dyssynchrony can be present in patients with WPW syndrome. Septal APs result in the greatest degree of LV mechanical dyssynchrony and afford the most benefit after RFA. This study supports further investigation in the relationship between electrical and mechanical activation using EPS and phase analysis of gated SPECT MPI.     

Stress-induced myocardial ischemia is associated with early post-stress left ventricular mechanical dyssynchrony as assessed by phase analysis of 201Tl gated SPECT myocardial perfusion imaging

Purpose

In ²⁰¹Tl SPECT myocardial perfusion imaging (MPI) data are acquired shortly after the stress injection to assess early post-stress left ventricle (LV) function. The purpose of this study was to use ²⁰¹Tl SPECT MPI to investigate whether stress-induced myocardial ischemia is associated with LV mechanical dyssynchrony.

Methods

Enrolled in the study were 75 patients who were referred for dipyridamole stress and rest ²⁰¹Tl gated SPECT MPI. The early post-stress scan was started 5?min after injection, and followed by the rest scan 4?h later. The patients were divided into three groups: ischemia group (N?=?25, summed stress score, SSS, ≥5, summed rest score, SRS, <5), infarct group (N?=?16, SSS ≥5, SRS ≥5) and normal group (N?=?34, SSS <5, SRS <5). LV dyssynchrony parameters were calculated by phase analysis, and compared between the stress and rest images.

Results

In the ischemia group, LV dyssynchrony was significantly larger during stress than during rest. On the contrary, LV dyssynchrony during stress was significantly smaller than during rest in the normal and infarct groups. LV dyssynchrony during rest was significantly larger in the infarct group than in the normal and ischemia groups. There were no significant differences in LV dyssynchrony during rest between the normal and ischemia groups.

Conclusion

Stress-induced myocardial ischemia caused dyssynchronous contraction in the ischemic region, leading to a deterioration in LV synchrony. Normal myocardium had more synchronous contraction during stress. The different dyssynchrony pattern between ischemic and normal myocardium early post-stress may aid the diagnosis of coronary artery disease using ²⁰¹Tl gated SPECT MPI.     

Optimal left ventricular lead position assessed with phase analysis on gated myocardial perfusion SPECT

Purpose

The aim of the current study was to evaluate the relationship between the site of latest mechanical activation as assessed with gated myocardial perfusion SPECT (GMPS), left ventricular (LV) lead position and response to cardiac resynchronization therapy (CRT).

Methods

The patient population consisted of consecutive patients with advanced heart failure in whom CRT was currently indicated. Before implantation, 2-D echocardiography and GMPS were performed. The echocardiography was performed to assess LV end-systolic volume (LVESV), LV end-diastolic volume (LVEDV) and LV ejection fraction (LVEF). The site of latest mechanical activation was assessed by phase analysis of GMPS studies and related to LV lead position on fluoroscopy. Echocardiography was repeated after 6?months of CRT. CRT response was defined as a decrease of ??15% in LVESV.

Results

Enrolled in the study were 90 patients (72% men, 67±10?years) with advanced heart failure. In 52 patients (58%), the LV lead was positioned at the site of latest mechanical activation (concordant), and in 38 patients (42%) the LV lead was positioned outside the site of latest mechanical activation (discordant). CRT response was significantly more often documented in patients with a concordant LV lead position than in patients with a discordant LV lead position (79% vs. 26%, p<0.01). After 6?months, patients with a concordant LV lead position showed significant improvement in LVEF, LVESV and LVEDV (p<0.05), whereas patients with a discordant LV lead position showed no significant improvement in these variables.

Conclusion

Patients with a concordant LV lead position showed significant improvement in LV volumes and LV systolic function, whereas patients with a discordant LV lead position showed no significant improvements.     

The evaluation of left ventricular dyssynchrony in hypertensive patients with a preserved systolic function undergoing gated SPECT myocardial perfusion imaging

Annals of Nuclear Medicine - Hypertension as a known risk factor for cardiovascular diseases can result in left ventricular dyssynchrony (LVD) leading to uncoordinated contraction. The aim of our...     

Evaluation of mechanical dyssynchrony and myocardial perfusion using phase analysis of gated SPECT imaging in patients with left ventricular dysfunction

Background. Using phase analysis of gated single photon emission computed tomography (SPECT) imaging, we examined the relation between myocardial perfusion, degree of electrical dyssynchrony, and degree of SPECT-derived mechanical dyssynchrony in patients with left ventricular (LV) dysfunction. Methods and Results. We retrospectively examined 125 patients with LV dysfunction and ejection fraction of 35% or lower. Fourier analysis converts regional myocardial counts into a continuous thickening function, allowing resolution of phase of onset of myocardial thickening. The SD of LV phase distribution (phase SD) and histogram bandwidth describe LV phase dispersion as a measure of dyssynchrony. Heart failure (HF) patients with perfusion abnormalities have higher degrees of dyssynchrony measured by median phase SD (45.5° vs 27.7°, P<.0001) and bandwidth (117.0° vs 73.0°, P=.0006). HF patients with prolonged QRS durations have higher degrees of dyssynchrony measured by median phase SD (54.1° vs 34.7°, P<.0001) and bandwidth (136.5° vs 99.0°, P=.0005). Mild to moderate correlations exist between QRS duration and phase analysis indices of phase SD (r=0.50) and bandwidth (r=0.40). Mechanical dyssynchrony (phase SD >43°) was 43.2%. Conclusions. HF patients with perfusion abnormalities or prolonged QRS durations have higher degrees of mechanical dyssynchrony. Gated SPECT myocardial perfusion imaging can quantify myocardial function, perfusion, and dyssynchrony and may help in evaluating patients for cardiac resynchronization therapy. (J Nucl Cardiol 2008;15:663-70.) This study was funded by a research grant from the Medtronic-Duke Strategic Alliance, and Dr Trimble is the primary investigator.     

门控心肌灌注SPECT相位分析技术评价心力衰竭患者左室不同步的价值

心脏再同步治疗(CRT)是晚期心力衰竭的重要治疗方法,从超声心动图(UCG)得到的左室机械不同步参数可作为CRT应答的重要预测因子,但在现有临床条件下,UCG技术包括组织多普勒成像(TDI)和心肌应变率成像,其作为常规临床手段来评价左室不同步还存在严重缺陷.目前的研究显示,门控心肌灌注SPECT相位分析技术能够用于CRT应答的预测,与基于UCG的TDI相比,其优势在于技术操作的高度自动化和结果的高度可重复性.     

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 left ventricular mechanical dyssynchrony by phase analysis of ECG-gated SPECT myocardial perfusion imaging

Cardiac resynchronization therapy (CRT) has shown benefits in patients with severe heart failure. However, at least 30% of patients selected for CRT by use of traditional criteria (New York Heart Association class III or IV, depressed left ventricular [LV] ejection fraction, and prolonged QRS duration) do not respond to CRT. Recent studies with tissue Doppler imaging have shown that the presence of LV dyssynchrony is an important predictor of response to CRT. Phase analysis has been developed to allow assessment of LV dyssynchrony by gated single photon emission computed tomography myocardial perfusion imaging. This technique uses Fourier harmonic functions to approximate regional wall thickness changes over the cardiac cycle and to calculate the regional onset-of-mechanical contraction phase. Once the onset-of-mechanical contraction phases are obtained 3-dimensionally over the left ventricle, a phase distribution map is formed that represents the degree of LV dyssynchrony. This technique has been compared with other methods of measuring LV dyssynchrony and shown promising results in clinical evaluations. In this review the phase analysis methodology is described, and its up-to-date validations are summarized.     

Can LV dyssynchrony as assessed with phase analysis on gated myocardial perfusion SPECT predict response to CRT?

Cardiac resynchronization therapy (CRT) is now a well-recognized therapeutic option for patients with end-stage heart failure. However, not all patients respond to CRT, and, therefore, preimplantation identification of responders is desirable. The aim of the present study was to investigate whether the degree of left ventricular (LV) dyssynchrony, as assessed with phase analysis from gated myocardial perfusion SPECT (GMPS), can predict which patients will respond to CRT. METHODS: Forty-two patients with severe heart failure, depressed LV ejection fraction, and wide QRS complex were prospectively included for implantation of a CRT device and underwent GMPS and 2-dimensional echocardiography as part of the clinical protocol. Clinical status was evaluated using the New York Heart Association (NYHA) classification, 6-min walk test, and quality-of-life score. The histogram bandwidth and phase SD (parameters indicating LV dyssynchrony) were assessed from GMPS, and the clinical status and echocardiographic variables were reassessed at 6-mo follow-up. RESULTS: Responders (71%) and nonresponders (29%) had comparable baseline characteristics, except for histogram bandwidth (175 degrees +/- 63 degrees vs. 117 degrees +/- 51 degrees [P < 0.01]) and phase SD (56.3 degrees +/- 19.9 degrees vs. 37 degrees .1 +/- 14.4 degrees [P < 0.01]), which were significantly larger in responders compared with nonresponders. Moreover, receiver-operating-characteristic curve analysis demonstrated an optimal cutoff value of 135 degrees for histogram bandwidth (sensitivity and specificity of 70%) and of 43 degrees for phase SD (sensitivity and specificity of 74%) for the prediction of response to CRT. CONCLUSION: Response to CRT is related to the presence of LV dyssynchrony assessed by phase analysis with GMPS. A cutoff value of 135 degrees for histogram bandwidth and of 43 degrees for phase SD could be used to predict response to CRT. Larger prospective studies are warranted to confirm the present findings.     

Left ventricular mass measured by myocardial perfusion gated SPECT. Relation to three-dimensional echocardiography

PURPOSE: The purpose of this investigation was to determine whether left ventricular mass (LVM) assessed from myocardial perfusion gated SPECT (GSPECT) data corresponds with echocardiographic estimates, and whether mass accuracy decreases as relative myocardial wall thickness increases. MATERIALS AND METHODS: Myocardial perfusion tomograms were selected retrospectively for 37 patients, of whom 18 had Tl-201 and 19 had Tc-99m sestamibi GSPECT poststress data collections, which were subsequently processed using quantitative gated SPECT software (Cedars Sinai Medical Center, Los Angeles, CA). These patients also had clinically indicated echocardiograms for assessment of wall thickness and possible valvular involvement. In addition, LV internal diameter and posterior wall thickness were measured at end-diastole by two-dimensional guided M-mode echocardiography to assess relative myocardial wall thickness, and LVM was measured by three-dimensional echocardiography using an acoustic spatial locator device. RESULTS: LVM values were not significantly different between GSPECT and three-dimensional echocardiography (153 +/- 39 g versus 146 +/- 35 g, respectively; P = NS). GSPECT correlated significantly (r = 0.63, P < 0.0001) with three-dimensional echocardiography, with a mean difference of 7 +/- 32 g but a substantial root mean squared error of 31 g. Results were similar for similar mass ranges when subgrouped by isotope and by the presence of significant myocardial perfusion defects. Results were independent of relative myocardial wall thickness determined by two-dimensional echocardiography. The two methods yielded similar results in the highest mass range of 400 to 500 g. CONCLUSIONS: GSPECT and three-dimensional echo LVM correlated significantly, but given the large spread of statistical errors, these two techniques should not be considered interchangeable. Because gamma camera resolution is limited, GSPECT LVM should be viewed as an approximation.     

Ventricular dyssynchrony assessed by gated myocardial perfusion SPECT using a geometrical approach: a feasibility study

Purpose  

Left ventricular dyssynchrony may predict response to cardiac resynchronization therapy and may well predict adverse cardiac events. Recently, a geometrical approach for dyssynchrony analysis of myocardial perfusion scintigraphy (MPS) was introduced. In this study the feasibility of this geometrical method to detect dyssynchrony was assessed in a population with a normal MPS and in patients with documented ventricular dyssynchrony.     

Prevalence and predictors of mechanical dyssynchrony as defined by phase analysis in patients with left ventricular dysfunction undergoing gated SPECT myocardial perfusion imaging

Background

A novel method to quantify dyssynchrony using phase analysis of single-photon emission computed tomography (SPECT) myocardial perfusion imaging has been developed. We sought to determine the prevalence of SPECT-derived mechanical dyssynchrony, and we report clinical variables which predict mechanical dyssynchrony in patients with left ventricular dysfunction.

Methods

We used a count-based Fourier analysis method to convert the regional myocardial counts from discrete frames per cardiac cycle into a continuous thickening function which allows resolution of the phase of the onset of myocardial contraction. The standard deviation of left ventricular phases (Phase SD) describes the regional phase dispersion as a measure of dyssynchrony. Significant dyssynchrony was defined as Phase SD ≥ 43°. 260 patients with left ventricular ejection fraction ≤35% were examined.

Results

The prevalence of mechanical dyssynchrony in the entire cohort of patients studied was 52%. Univariate predictors of Phase SD were age (P = .03), black race (P = .0005), QRS duration, EF, EDV, summed stress score (SSS), and summed rest score (SRS) (all P = <.0001). Black race, male gender, QRS EF, and SRS were independent predictors of SPECT-based mechanical dyssynchrony.

Conclusions

Significant SPECT-based mechanical dyssynchrony is relatively common among patients with left ventricular dysfunction. In a population of patients with predominantly ischemic heart disease referred for SPECT, a reduced EF, increasing QRS duration, severity and extent of myocardial scar on SPECT imaging are independent predictors of mechanical dyssynchrony and may serve to identify patients for dyssynchrony screening.     

Left ventricular shape index assessed by gated stress myocardial perfusion SPECT: Initial description of a new variable

Background  Ventricular remodeling is predictive of congestive heart failure (CHF). We aimed to automatically quantify a new myocardial shape variable on gated myocardial perfusion single photon emission computed tomography (SPECT) (MPS) and to evaluate the association of this new SPECT parameter with the risk of hospitalization for CHF. Methods and Results  A computer algorithm was used to measure the 3-dimensional (3D) left ventricular (LV) shape index (LVSI), derived as the ratio of maximum 3D short- and long-axis LV dimensions, for end systole and end diastole. LVSI normal limits were obtained from stress technetium 99m sestamibi MPS images of 186 patients (60% of whom were men) (control subjects) with a low likelihood of CAD (<5%). These limits were tested in a consecutive series of 93 inpatients (85% of whom were men) having MPS less than 1 week after hospitalization, of whom 25 were hospitalized for CHF exacerbation. Variables associated with CHF hospitalization were tested by receiver operating characteristic curve and multivariate logistic regression analyses. LVSI repeatability was assessed in 52 patients with ischemic cardiomyopathy who had sequential stress MPS within 60 days after the initial MPS without clinical events in the interval between MPS studies. Control subjects had lower end-systolic and end-diastolic LVSIs compared with patients with CHF and those without CHF (P <.001). Receiver operating characteristic curve areas for the prediction of hospitalization as a result of CHF were similar for LV ejection fraction and end-systolic LVSI. End-systolic and end-diastolic LVSIs were independent predictors of CHF hospitalization by multivariate analysis; however, end-systolic LVSI had the greatest added value among all tested variables. Repeatability was excellent for both end-systolic LVSI (R2 = 0.85, P < .0001) and end-diastolic LVSI (R2 = 0.82, P < .001). Conclusion  LVSI is a promising new 3D variable derived automatically from gated MPS providing highly repeatable ventricular shape assessment. Preliminary findings suggest that LVSI might have clinical implications in patients with CHF. Supported in part by grants from Bristol-Myers Squibb Medical Imaging, Inc, Billerica, Mass, and Astellas Pharma US, Deerfield, Ill.     

Left ventricular mass from gated SPECT myocardial perfusion imaging: Comparison with cardiac computed tomography

Background

Increased left ventricular mass (LVM) has been correlated with adverse cardiac events, such as sudden cardiac death. However, LVM quantitation with widely utilized gated SPECT myocardial perfusion imaging (MPI) software, has little validation and clinical application. Thus, we compared LVM from two commonly employed gated SPECT packages [4D-MSPECT^® (4DM) and Quantitative Perfusion SPECT^® (QPS)] with the 3-dimensional reference standard, CT angiography (CTA).

Methods

Comparisons were made in 56 patients (mean age 61.4 ± 14.6; 32% female) referred for dual-isotope or low-dose/high-dose Tc-99m-tetrofosmin rest/stress MPI and cardiac CTA (mean 1.5 ±4.5 months apart). LVM measurement was performed for both CTA and MPI by two independent observers blinded to clinical information.

Results

Correlation with CTA was best for post-stress MPI than at rest; thus, post-stress values are reported. Values obtained with each of the techniques were very highly reproducible (interobserver correlation r = 0.99 for each technique). The mean LVM values were 142 g by CTA, 145 g by 4DM, and 135 g by QPS (P = NS for CTA vs SPECT, but P < .001 for 4DM vs QPS). There was moderately good correlation between CTA and SPECT LVM data (r = 0.74 and 0.72 for 4DM and QPS, respectively; both P < .001). However, on Bland-Altman analysis there was significant overestimation of lower values and underestimation of higher CT LVM values by both QPS and 4DM (both r = 0.68 and 0.69, P < .001). The limits of agreement relative to CT LVM were wide (?52.1 g to 64.1 g for QPS; and ?60.0 g to 53.5 g for 4DM).

Conclusions

SPECT and CTA give reproducible measures of LVM. Using CTA as the reference standard, the mean SPECT LVM values are similar, but lower values are overestimated and higher values are underestimated. Thus, the SPECT values are not substitutable for CTA without mathematical correction.     

Left ventricular function parameters obtained from gated myocardial perfusion SPECT imaging: a comparison of two data processing systems

BACKGROUND AND AIM: The Cedars-Sinai Quantitative Gated Single Photon Emission Computed Tomography (SPECT) (QGS) program, used to quantify left ventricular function parameters from gated myocardial perfusion scintigraphy (MPS), has been extensively validated and compared with other methods of quantification. However, little is known about the reproducibility of QGS on different processing systems. This study compared the findings of QGS running on workstations provided by two different manufacturers. METHODS: Gated rest MPS studies of 50 patients were analysed retrospectively. Filtered back-projection (FBP) was performed using identical parameters on Philips Pegasys and Nuclear Diagnostics Hermes workstations to produce gated short-axis (SA) slices. In addition, the gated SA slices reconstructed on the Pegasys were transferred to the Hermes. QGS was used to calculate the end-diastolic volume (EDV), end-systolic volume (ESV) and left ventricular ejection fraction (LVEF) in each case. RESULTS: The mean+/-standard deviation differences between the Pegasys and Hermes function parameters were -7.06+/-3.91 ml (EDV), -5.54+/-3.21 ml (ESV) and +1.14%+/-1.43% (LVEF) when data were reconstructed on different systems, and -0.16+/-1.58 ml (EDV), -0.10+/-1.02 ml (ESV) and +0.14%+/-0.73% (LVEF) when data were reconstructed on the same system. Bland-Altman plots showed definite trends for EDV and ESV for data reconstructed on different systems, but no trends were seen for data reconstructed on the same system. CONCLUSIONS: When data were reconstructed on two separate systems, the difference between the function parameters obtained from Pegasys and Hermes could be ascribed to differences in the reconstruction process on each system despite the use of identical parameters (filters, etc). However, when the same reconstructed data were analysed on both systems, no significant difference in left ventricular function parameters was observed.     

Use of phase analysis of gated SPECT perfusion imaging to quantify dyssynchrony in patients with mild-to-moderate left ventricular dysfunction

Background  

CRT has been shown to be beneficial in the majority of patients with NYHA class III-IV symptoms, prolonged QRS duration, and an EF ≤35%. The use of imaging modalities to quantify dyssynchrony may help identify patients who may benefit from CRT, but do not meet current selection criteria. We hypothesize that patients with mild-to-moderate LV dysfunction have significant degrees of mechanical dyssynchrony.