Low-dose dobutamine stress gated blood pool SPECT assessment of left ventricular contractile reserve in ischemic cardiomyopathy: a feasibility study.

PURPOSE: The purpose of the present study was to evaluate the feasibility of gated blood pool single-photon emission computed tomography (GBPS) with low-dose dobutamine (LDD) stress test, performed on a single-photon emission computed tomography (SPECT) camera equipped with cadmium-zinc-telluride (CZT) solid-state detectors, in assessing of left ventricle (LV) contractile reserve in patients with ischemic cardiomyopathy (ICM). METHODS: A total of 52 patients (age 59 ± 7.2 years, 47 men and 5 women) with ICM and a control group of 10 patients without obstructive coronary artery lesion underwent GBPS and transthoracic echocardiography (TTE) at rest and during LDD stress test (5, 10, 15 µg/kg/min). The duration of each GBPS step was 5 min. Stress-induced changes in LV ejection fraction (ΔLVEF), peak ejection rate, LV volumes, and mechanical dyssynchrony (phase histogram standard deviation, phase histogram bandwidth and entropy) obtained with GBPS were estimated. RESULTS: All GBPS indices except end-diastolic volume showed significant dynamics during stress test in both groups. The majority of parameters in ICM patients showed significant changes at a dobutamine dose of 10 µg/kg/min as compared to the rest study. Seventeen percent of ICM patients, but none from the control group, showed a decrease in LVEF during stress, accompanied by a significant increase in entropy. The intra- and inter-observer reproducibility was excellent for both rest and stress studies. There was a moderate correlation (r = 0.5, p = 0.01) between GBPS and TTE, with a mean difference value of - 1.7 (95% confidence interval - 9.8; 6.4; p = 0.06) in ΔLVEF. CONCLUSION: Low-dose dobutamine stress GBPS performed with high-efficiency CZT-SPECT cameras can be performed for evaluating stress-induced changes in LV contractility and dyssynchrony with lower acquisition time. A dobutamine dose of 10 µg/kg/min can potentially suffice to detect stress-induced changes in patients with ICM during GBPS. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT04508608 (August 7, 2020).

Analysis of Differences in Assessment of Left Ventricular Function on Echocardiography and Nuclear Perfusion Imaging.

Two widely used methods for left ventricular (LV) ejection fraction (EF) determination, echocardiography (echo) and gated single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI), often have wide limits of agreement. Factors influencing discrepancies between core laboratory echo and MPI LVEF determinations were examined in a large series of heart failure (HF) subjects and normal controls. 879 HF and 101 control subjects had core lab analyses of echo and MPI (mean time between procedures 7-8 days). LVEF differences were analyzed using one-way analysis of variance and Bland-Altman plots. Relationships between LVEF differences and patient characteristics and outcome endpoints (mortality and arrhythmias) were explored with logistic regression, Cox proportional hazards models, and Kaplan-Meier survival analyses. There was a systematic difference between the 2 modalities; echo LVEF was higher with more severe LV dysfunction, MPI LVEF higher when systolic function was normal. LVEF results were within ±5% in only 37% of HF and 23% of control subjects. Considering discordance around the LVEF threshold 35%, there was disagreement between the 2 methods in 305 HF subjects (35%). Male gender (odds ratio (OR) = 0.200), atrial fibrillation (OR = 2.314), higher body mass index (OR = 1.051) and lower LV end-diastolic volume (OR = 0.985) were the strongest predictors of methodologic discordance. Cardiac event rates were highest if both LVEF values were ≤35% and lowest when both LVEF values were >35%. In conclusion, substantial disagreements between LVEF results by echo and MPI are common. HF patients with LVEF ≤35% by both techniques have the highest 2-year event risk.

Left ventricle function assessment using gated first-pass 18F-FDG PET: Validation against equilibrium radionuclide angiography.

PURPOSE: We appraised the feasibility of left ventricle (LV) function assessment using gated first-pass 18F-FDG PET, and assessed the concordance of the produced measurements with equilibrium radionuclide angiography (ERNA). MATERIALS AND METHODS: Twenty-four oncologic patients benefited from 99mTc-labeled red-blood-cell ERNA, in planar mode (all patients) and using SPECT (22 patients). All patients underwent gated first-pass 18F-FDG cardiac PET. Gated dynamic PET images were reconstructed over 1 minute during tracer first-pass inside the LV and post-processed using in-house software (TomPool). After re-orientation into cardiac canonical axes and adjustment of the valves plane using a phase image, pseudo-planar PET images obtained by re-projection were automatically segmented using thresholded region growing and gradient-based delineation to produce an LV ejection fraction (EF) estimate. PET images were also post-processed in fully-tomographic mode to produce LV end diastole volume (EDV), end systole volume (ESV), and EF estimates. Concordance was assessed using Lin's concordance (ccc) and Bland-Altman analysis. Reproducibility was assessed using the coefficient of variation (CoV) and intra-class correlation (ICC). RESULTS: Pseudo-planar PET EF estimates were concordant with planar ERNA (ccc = 0.81, P < .001) with a bias of 0% (95% CI [- 2%; 3%], limits of agreement [- 11%; 12%]). Reproducibility was excellent and similar for both methods (CoV = 2 ± 1% and 3 ± 2%, P = NS; ICC = 0.97 and 0.92, for PET and ERNA, respectively). Measurements obtained in fully-tomographic mode were concordant with SPECT ERNA: ccc = 0.83 and bias = - 3 mL for LV EDV, ccc = 0.92 and bias = 0 mL for LV ESV, ccc = 0.89 and bias = - 1% for LV EF (all P values < .001 for ccc, all biases not significant). CONCLUSIONS: Gated first-pass 18F-FDG PET might stand as a relevant alternative to ERNA for LV function assessment, enabling a joint evaluation of both therapeutic response and cardiac toxicity in oncologic patients receiving cardiotoxic chemotherapy.

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

PURPOSE: To compare, vs CMR, four softwares: quantitative gated SPECT (QGS), myometrix (MX), corridor 4DM (4DM), and Emory toolbox (ECTb) to evaluate left ventricular ejection fraction (LVEF), end-systolic (ESV), and end-diastolic volumes (EDVs) by gated MPI CZT-SPECT. METHODS: 48 patients underwent MPI CZT-SPECT and CMR 6 weeks after STEMI, LV parameters were measured with four softwares at MPI CZT-SPECT vs CMR. We evaluated (i) concordance and correlation between MPI CZT-SPECT and CMR, (ii) concordance MPI CZT-SPECT/CMR for the categorical evaluation of the left ventricular dysfunction, and (iii) impacts of perfusion defects > 3 segments on concordance. RESULTS: LVEF: LCC QGS/CMR = 0.81 [+ 2.2% (± 18%)], LCC MX/CMR = 0.83 [+ 1% (± 17.5%)], LCC 4DM/CMR = 0.73 [+ 3.9% (± 21%)], LCC ECTb/CMR = 0.69 [+ 6.6% (± 21.1%)]. ESV: LCC QGS/CMR = 0.90 [- 8 mL (± 40 mL)], LCC MX/CMR = 0.90 [- 9 mL (± 36 mL)], LCC 4DM/CMR = 0.89 [+ 4 mL (± 45 mL)], LCC ECTb/CMR = 0.87 [- 3 mL (± 45 mL)]. EDV: LCC QGS/CMR = 0.70 [- 16 mL (± 67 mL)], LCC MX/CMR = 0.68 [- 21 mL (± 63 mL], LCC 4DM/CMR = 0.72 [+ 9 mL (± 73 mL)], LCC ECTb/CMR = 0.69 [+ 10 mL (± 70 mL)]. CONCLUSION: QGS and MX were the two best-performing softwares to evaluate LVEF after recent STEMI.

Assessment of left ventricular ejection fraction with cardiofocal collimators: Comparison between IQ-SPECT, planar equilibrium radionuclide angiography, and cardiac magnetic resonance.

BACKGROUND: IQ-SPECT has been shown to significantly reduce acquisition time and administered dose while preserving image quality in myocardial perfusion imaging. Whether IQ-SPECT provides accurate left ventricular ejection fractions (LVEF) with gated blood pool SPECT (GBPS) remains unknown. METHODS: Sixty patients underwent IQ-SPECT GBPS and planar imaging. Among those patients, 11 underwent both cMRI and GBPS. GBPS LVEF, LVEDV, and LVESV were calculated using 2 validated software; QBS (Cedars-Sinai Medical Center, Los Angeles, USA) and MHI (Montreal Heart Institute, Montreal, Canada). LVEF, LVEDV, and LVESV obtained with the different modalities were compared. RESULTS: Average planar LVEF was 48 ± 11% (mean ± SD), average LVEDV was 177 ± 59 mL (range 63 to 342 mL), and average LVESV was 96 ± 46 mL (range 16 to 234 mL). GBPS LVEF and their correlation coefficient with planar LVEF were 40 ± 12% (r = 0.70) and 44 ± 12% (r = 0.83) with QBS and MHI, respectively. Correlation coefficient between cMRI and planar LVEF was 0.65 and were 0.69 and 0.52 between cMRI and GBPS using QBS and MHI, respectively. CONCLUSIONS: LVEF calculated with GBPS using IQ-SPECT correlates with planar measurements. Correlation is best using the MHI method and variation is independent of LVEDV.

Equilibrium radionuclide ventriculography: still a clinically useful method for the assessment of cardiac function?

18 The non-invasive assessment of left ventricular function with simple indices, such as left ventricular volumes and ejection fraction (LVEF), offers significant diagnostic and prognostic implications in the entire spectrum of cardiac diseases. Equilibrium radionuclide ventriculography (RNV) is a well validated technique for this purpose. Based on the principle that the amount of radioactivity emitted by technetium-99m (99mTc)-pertechnate labeled erythrocytes in the cardiac chambers is proportional to the amount of bloodcontained, reproducible and accurate LVEF measurements can be obtained, with practically no geometric assumptions regarding heart shape. However, the development of other imaging techniques, mostly echocardiography and secondarily cardiac magnetic resonance has led to a decline in the use of RNV. This is due to easiness, cost and availability issues and also because competitive modalities can offer reliable anatomic and functional information and hence they can address a variety of clinical scenarios in one session. Nevertheless, RNV still remains a reliable method in clinical conditions, in which the detection of small changes in LVEF may be important in clinical decision-making, such as in patients undergoing cardiotoxic chemotherapy, when the images of different methods are of suboptimal quality or unobtainable, or there is discordance between clinical judgment and imaging results. In this respect the more recently introduced gated single photon emission tomography (SPET) myocardial perfusion imaging has not demonstrated equivalent reliability, in terms of independence from a variety of factors and accuracy of measurements on a per-patient basis. The purpose of this review is to present the features of RNV, and to define its role in the evaluation of cardiac function in the current era of medical imaging.

Assessment of segmental left ventricular thickening in diabetic type II obese patients with normal myocardial perfusion scan.

OBJECTIVE: The aim of this study is to investigate whether gated single photo emission tomography (gSPET) can be used to detect subclinical left ventricular systolic dysfunction (LVSD) in obese diabetic type II patients. SUBJECTS AND METHODS: We retrospectively reviewed gSPET images of 190 patients with diabetes mellitus type II (DM II) (137 females and 53 males) with normal myocardial perfusion and normal ejection fraction (EF). Standardized twenty segment polar maps of thickening and motion were generated. Correlation between body mass index (BMI) and thickening for each segment was performed. RESULTS: Statistically significant results were reported in female patients including: negative correlation between BMI and EF (-0.19, P=0.03). End diastolic volume (EDV) also significantly increased with increasing BMI (0.25, P<0.01). There was also statistically significant negative correlation between septal thickening and BMI segment 15 (-0.19, P=0.02), segment 16 (-0.22, P=0.01), segment 18 (-0.20, P=0.01), segment 19 (-0.25, P=0.003), segment 20 (-0.2, P=0.02)]. No statistical significant correlation was found between thickening and BMI in male patients. CONCLUSION: This is the first time where thickening as measured by gSPET has been used to demonstrate subclinical LVSD in DM II obese patients. The relationship between gender and obesity on cardiovascular function and structure needs further investigations.

Results of performing or not cardiac resynchronization therapy for live assessment of LV function and mechanical systole synchrony using gated myocardial perfusion imaging and real-time three-dimensional echocardiography. Seven months follow-up.

We studied a 50 years old male patient who underwent cardiac resynchronization therapy on and off (CRT-on and CRT-off) for assessment of left ventricular (LV) function and mechanical systole synchrony using gated myocardial perfusion imaging (gMPI) and real-time three-dimensional echocardiography (RT3DE). The patient was reexamined after seven months. The comparison of these two modalities showed consistent results on assessing both the CRT-on and CRT-off conditions. This result may indicate that an immediate synchronization parameter change during CRT-on may be valuable for predicting response to CRT surgery.

Cardiac CT assessment of left ventricular mass in mid-diastasis and its prognostic value.

AIMS: To determine the influence of cardiac motion on measurements of left ventricular (LV) mass obtained with 64-slice computed tomography (CT) and to elucidate the prognostic value of LV mass on major adverse cardiac events (MACE) and all-cause mortality. Increased LV mass has been linked with MACE. Although Cardiac CT allows measurement of LV anatomy, it is susceptible to motion artefacts often requiring image acquisition during diastasis. There is a need to understand variability in LV mass measurements across phases of the cardiac cycle, and whether mid-diastolic measurements have prognostic value. METHODS AND RESULTS: The study comprised two equally sized cohorts of patients that had undergone retrospectively gated cardiac CT: patients who had MACE and/or all-cause death at follow-up and a matched (age, sex, and risk factors) event-free cohort. LV mass was measured at mid-diastole, end-diastole, and end-systole. Correlation and agreement between phases were determined. The incremental value of mid-diastolic hypertrophy (LVH) over the National Cholesterol Education Programme (NCEP) risk was performed for LV mass indices normalized to body surface area (LVMIBSA) or weight (LVMIWeight). Of 166 patients, 31.3% experienced MACE and 28.9% died of any cause (follow-up 22.9 ± 13.4 months). LV mass at all cardiac phases were strongly correlated (r > 0.94). Mean mid-diastolic LVMIBSA was higher in the cohort with events (93.7 vs. 80.7 g/m2, P= 0.008) as was LVMIWeight (2.26 vs. 1.88 g/kg, P = 0.001). LVMIBSA and LVMIWeight had prognostic value incremental to NCEP with 1.85 and 2.47 hazard ratios, respectively. CONCLUSIONS: Measurement of LV mass can be obtained by cardiac CT images obtained at mid-diastasis. LV mass measurements obtained at mid-diastasis have prognostic value.

Clinical values of left ventricular mechanical dyssynchrony assessment by gated myocardial perfusion SPECT in patients with acute myocardial infarction and multivessel disease.

PURPOSE: The aim of this study was to evaluate the prognostic value of additional evaluation of left ventricular mechanical dyssynchrony (LVMD) by gated myocardial perfusion single-photon emission computed tomography (GMPS) in patients with acute myocardial infarction (MI) and multivessel disease. METHODS: One hundred and nine acute MI patients with >50 % stenosis in at least one non-culprit artery who underwent GMPS within 2 weeks were enrolled. All patients underwent successful revascularization of the culprit arteries. Those with previous MI, atrial fibrillation, or frequent ventricular premature complexes, cardiac devices, significant patient motion, or procedure-related events were excluded. Phase standard deviation (PSD) and phase histogram bandwidth (PBW) were measured for assessment of LVMD. Patients were followed up for a median of 26 months after index MI, for composite major adverse cardiac events (MACE), which consisted with all-cause death, unplanned hospitalization due to heart failure and severe ventricular arrhythmias (sustained ventricular tachycardia or ventricular fibrillation). Independent predictors of MACE were evaluated. RESULTS: MACE occurred in 22 patients (20 %). Stress PSD (53.3 ± 17.3° vs. 35.3 ± 18.9°; p <0.001), stress PBW (147.6 ± 54.6° vs. 96.8 ± 59.2°; p = 0.001) and resting PBW (126.8 ± 37.5° vs. 96.6 ± 48.9°; p = 0.001) were significantly higher in patients with MACE compared to those without. Multivariate analysis revealed that stress PSD ≥45.5° and stress PBW ≥126.0° were predictive of MACE, as well as suboptimal non-culprit artery revascularization (SNR) and renin-angiotensin system (RAS) blockade medication. Higher stress PSD and stress PBW were associated with poorer prognosis both in patients with and without SNR, and those with RAS blockade medication, but not in those without RAS blockade medication. CONCLUSIONS: LVMD measured by GMPS showed added prognostic value in acute MI with multivessel disease. GMPS could serve as a comprehensive evaluation imaging tool in patients with acute MI and multivessel disease.

[Radionuclide Methods in the Assessment of Anthracycline-Induced Cardiotoxicity].

PURPOSE: To compare diagnostic efficacy of multigated acquisition (MUGA) scan and Tc-99m MIBI gated SPECT for evaluation and forecast of anthracycline-induced cardiotoxicity. MATERIAL AND METHODS: We included into this study 80 patients (72 women and 8 men, mean age 43 ± 4.2 years) with malignant tumors without overt pathology of the cardiovascular system. These patients received doxorubicin (50 mg/m2 per course) based cytostatic therapy. All patients were studied either by MUGA (n = 40) or 99MTc MIBI gated SPECT (n = 40) before initiation of chemotherapy 1 hour after first administration of doxorubicin and after the 4th course. RESULTS: After administration of 50 mg/m2 of doxorubicin 14 patients according to MUGA scan and 16 patients according to 99mTc MIBI gated SPECT had significant (≥ 10%) reduction of left ventricular ejection fraction (LVEF). Significant inhibition of systolic function in these patients remained after the 4th course of treatment. Individual analysis of the MUGA and 99mTc MIBI gated SPECT data registered after the fourth course (achievement of total doxorubicin dose of 200 mg/m2) showed that ≥ 10% LVEF reduction in response to the first dose of doxorubicin could predict the development of cumulative cardiotoxicity. CONCLUSION: MUGA scan and 99mTc MIBI gated SPECT can be applied with equal effectiveness for assessment of acute and chronic anthracycline-induced cardiotoxicity in patients with malignant tumors. LVEF reduction ≥ 10% in response to the first dose of doxorubicin appeared to be a predictor of development of chronic cardiotoxicity.

Effects of filtration on right ventricular function by the gated blood pool SPECT.

OBJECTIVE: Gated blood po ol single photon emission computed tomography (GBPS) offers the possibility of obtaining additional functional information from blood pool studies, including evaluation of left and right ventricular function simultaneously. The calculation of ventricular volumes based on the identification of the endocardial surface would be influenced by the spatial resolution in the reconstructed images. This study was performed to evaluate the effect of different filters on the right ventricular function. METHODS: The normal four-dimensional (4-D) NURBS-based cardiac-torso (NCAT) phantom with known right ventricular volume and ejection fraction was generated. The SIMIND Monte Carlo program was used to create projections. The studies were reconstructed by FBP and post-processing filtration such as Butterworth, Hanning, Shepp-Logan, Metz and Wiener in different statuses (cutoff and order). Using the Cedars-Sinai QBS (quantitative blood pool SPECT) package, the ventricular functional parameters were computed. The calculated values were analyzed and compared with the normal NCAT results. RESULTS: The results implied that the calculated right ventricular end diastolic volume (RVEDV) by Butterworth filtration (cutoff frequency = 0.3) agreed more with the NCAT Phantom characteristics [relative difference percentage (RDP) = 1.2 %], while the maximum accordance in the calculation of the RV ejection fraction (EF) (RDP = 3 %) was observed by Metz filter (FWHM 20 pixel). Also, the results of this study demonstrate that the Butterworth filter provided the most stable values (cutoff frequency = 0.4-0.5) in the estimation of RVEDV (RDP = 7.5 %). The Hanning and Shepp-Logan filters produced a much larger RDP, particularly in low frequency (41.1 and 21.5 %, respectively) compared to other filters. CONCLUSIONS: This study demonstrated that the operation of different filters has a severe effect in computing right ventricular volume. The resolution recovery and Butterworth filters tend to give more comparable ventricular volumes with the actual normal NCAT value. Further evaluation using a large clinical database is underway to evaluate the optimum protocol in a clinical setting.

Assessment of left ventricular systolic and diastolic function using ECG-gated technetium-99m tetrofosmin myocardial perfusion SPECT.

Because left ventricular (LV) diastolic dysfunction is frequently the earliest indicator of LV dysfunction in patients with heart failure, the estimation of LV diastolic function is very important. On the other hand, electrocardiography (ECG)-gated technetium (Tc) -99m tetrofosmin single-photon emission computed tomography (SPECT) has been reported to be a useful method for evaluation of LV function. The objective of this study was to examine the usefulness of ECG-gated Tc-99m tetrofosmin SPECT in terms of estimation of cardiac diastolic function. Consecutive 145 patients underwent an ECG-gated Tc-99m tetrofosmin SPECT to estimate systolic and diastolic LV function, and were compared with those evaluated by ultrasound echocardiography (UCG). LV end-diastolic volume, LV end-systolic volume, and LV ejection fraction values obtained by quantitative gated SPECT (QGS) showed significant positive linear correlations with those obtained by UCG. All 145 patients were classified into 3 groups according to diastolic function estimated by UCG. The first-third mean filling rate (1/3 MFR) and peak filling rate (PFR) that revealed the LV diastolic function of the group B (normal systolic function and mild diastolic dysfunction) patients (1.01 ± 0.35, 1.85 ± 0.57) were both significantly lower than those of the group A (normal systolic and diastolic function) patients (1.43 ± 0.37, 2.43 ± 0.56). The 1/3 MFR and PFR of the group C (moderate ~ severe systolic and diastolic dysfunction) patients (0.47 ± 0.34, 0.92 ± 0.62) were also significantly lower than those of the group A and B patients. QGS may be a useful method for the evaluation of cardiac systolic and diastolic function, especially in patients with normal systolic function and diastolic dysfunction.

Quantitative assessment of cardiac mechanical synchrony using equilibrium radionuclide angiography.

BACKGROUND: Data on normal parameters of cardiac mechanical synchrony is limited, variable and obtained from small cohorts till date. In most studies, software used for such assessment has not been mentioned. The aim of study is to establish normal values of mechanical synchrony with equilibrium radionuclide angiography (ERNA) in a larger population using commercially available software. METHODS: We retrospectively analysed ERNA studies of 108 patients having low pretest likelihood of coronary artery disease, no known history of cardiac disease, normal electrocardiogram and whose ERNA studies were considered normal by experienced observers. In addition, ten patients diagnosed with dilated cardiomyopathy (DCM) and having LVEF ≤ 40% underwent ERNA. Fourier first harmonic analysis of phase images was used to quantify synchrony parameters using commercially available software (XT-ERNA). Intraventricular synchrony for each ventricle was measured as the standard deviation of the LV and RV mean phase angles (SD LVmPA and SD RVmPA, respectively). Interventricular synchrony was measured as LV-RVmPA. Absolute interventricular delay was calculated as absolute difference between LV and RVmPA (without considering ± sign). All variables were expressed in milliseconds (ms) and degree (°). Intra-observer and inter-observer variabilities were assessed. Cut-off values for parameters were calculated from the normal database, and validated against patient group. RESULTS: On phase analysis, LVmPA was observed to be 343 ± 48.5 milliseconds (174.7° ± 18.5°), SD LVmPA was 16.3 ± 5.4 milliseconds (8.2° ± 2.5°), RVmPA was 339 ± 50.4 milliseconds (171.8° ± 18.5°) and SD RVmPA was 37.3 ± 15.7 milliseconds (18.7° ± 7.2°). LV-RVmPA was observed to be 3.9 ± 21.7 milliseconds (2.9° ± 9.6°) and absolute interventricular delay was 16.3 ± 14.8 milliseconds (7.9° ± 6.1°). The cut-off values for the presence of dyssynchrony were estimated as SD LVmPA > 27.1 milliseconds (>13.2°), SD RVmPA > 68.7 milliseconds (>33.1°) and LV-RVmPA > 47.3 milliseconds (>22.1°). There was no statistically significant intra-observer or inter-observer variability. Using these cut offs, 9 patients with DCM showed the presence of left intraventricular dyssynchrony, 5 had right intraventricular dyssynchrony and 2 had interventricular dyssynchrony. CONCLUSIONS: ERNA phase analysis offers an objective and reproducible tool to quantify cardiac mechanical synchrony using commercially available software and can be used in routine clinical practice to assess mechanical dyssynchrony.

Relationship between left ventricular dyssynchrony and systolic dysfunction is independent of impaired left ventricular myocardial perfusion in heart failure: assessment with 99mTc-sestamibi gated myocardial scintigraphy.

BACKGROUNDS: Left ventricular (LV) dyssynchrony reduces LV systolic function in patients with heart failure (HF). However, it remains unknown whether this relationship is independent of impaired LV myocardial perfusion. METHODS AND RESULTS: A total of 105 patients with chronic HF (age 71 ± 13 years; 71 men) were enrolled in the present study. (99m)Tc-sestamibi (MIBI) gated myocardial scintigraphy was performed at rest to assess LV myocardial perfusion as evaluated by the total defect score of perfusion Single Photon Emission Computed Tomography images (TDS-MIBI), LV systolic function as evaluated by LV ejection fraction (LVEF), and LV systolic dyssynchrony as evaluated by the maximal difference of time to end systole (MD-TES), which is the time lag between the earliest and the latest end systole among 17 LV segments analyzed with a novel program, "cardioGRAF". The mean ± SD (minimum and maximum range) of the MD-TES was 147.8 ± 117.5 (14.0-458.3)ms. The MD-TES was significantly higher in patients with LVEF<45% (199.4 ± 117.6 ms) than in those with LVEF ≥ 45% (60.5 ± 41.2 ms, p<0.001). In a multiple logistic regression analysis, the MD-TES showed an increased odds ratio for LVEF<45% (2.46 [95% CI; 1.51-4.01] per increment in decile of MD-TES rank, p<0.001), after adjusting for the TDS-MIBI, history of myocardial infarction, and other potential confounders. CONCLUSIONS: LV dyssynchrony is a significant determinant of LV systolic dysfunction in patients with HF, and this relationship is independent of impaired LV myocardial perfusion and history of myocardial infarction.

Influence of CT-based attenuation correction in assessment of left and right ventricular functions with count-based gated blood-pool SPECT.

OBJECTIVE: Influence of CT-based attenuation correction (CT-AC) in assessment of left and right ventricular functions with count-based gated blood-pool SPECT (GBPS) was evaluated in a mixed population. METHODS: Thirty-two patients (81% male; mean age 56 ± 12) referred for various symptoms or heart diseases were prospectively included. Data from 32 GBPS acquisitions were reconstructed using an iterative algorithm with (IRAC) and without (IRNC) CT-AC and analyzed using previously described segmentation software based on the watershed algorithm. LV and RV EF and volumes were assessed with and without CT-AC and compared. RESULTS: EF and volumes were correlated (P < .001 for all parameters with r = 0.97 for LV and RV EF; r = 0.96 for LV EDV; r = 0.98 for LV ESV; r = 0.96 for RV EDV and ESV). The mean values using IRAC and IRNC were different for all parameters with lower EF (respectively, 49% ± 19% vs 51 %± 18%; P = .002 for LV EF and 50% ± 14% vs 54%±15%; P < .001 for RV EF) and higher volumes (respectively, 142 ± 41 mL vs 133 ± 40 mL; P < .001 and 79 ± 45 mL vs 71 ± 42 mL; P < .001 for LV EDV and ESV; 91 ± 32 mL vs 86 ± 31 mL; P = .003 and 48 ± 28 mL vs 43 ± 26 mL; P < .001 for RV EDV and ESV). Limits of agreement were -11% to 6% and -11% to 4% for LV and RV EF. We found wider limits of agreement for LV volumes (-13 to 32 mL for EDV and -10 to 27 mL for ESV) than for RV volumes (-13 to 23 mL for EDV and -9 to 20 mL for ESV). Taking into account all volumes, we found a trend with a significant positive correlation between means and differences in volumes assessed with and without CT-AC. CONCLUSION: Assessment of both left and right ventricular functions by count-based GBPS with CT-AC showed higher volumes and lower EF. Differences were slight, especially for the range of normal to subnormal ventricular volumes.

Feasibility of an accurate assessment of myocardial salvage by comparing functional and perfusion abnormalities in post-reperfusion gated SPECT.

BACKGROUND: Because of persistent stunning, post-treatment functional abnormalities could identify the initial risk area. The study aims to detect myocardial salvage using post-revascularization gated SPECT in acute myocardial infarction (AMI) treated by reperfusion therapy. METHODS: In 36 AMI patients, we performed a first gated SPECT injecting (99m)Tc-sestamibi before primary percutaneous coronary intervention (PCI), and a second 5 days later. The salvage index defined by the two perfusion images was compared with the value obtained by subtracting in the second gated SPECT the extent of perfusion defect from the extent of wall thickening abnormalities. RESULTS: The wall thickening salvage index correlated with the reference perfusion salvage index (Spearman's ρ = .92, P < .0001), with a 95% limit of agreement = ±.25. The agreement between the classifications in salvage index tertiles of the reference and of the wall thickening salvage index was good (kappa = .75). All patients with optimal PCI result and 18/24 of those with intermediate or poor outcome were correctly classified. CONCLUSIONS: Comparing function and perfusion in a single post-PCI (99m)Tc-sestamibi gated SPECT it is possible to estimate myocardial salvage. This could have useful implications in studies comparing different treatment strategies for AMI.

Evaluation of ventricular synchrony with equilibrium radionuclide angiography: assessment of variability and accuracy.

BACKGROUND AND AIMS: Equilibrium radionuclide angiography (ERNA) has become an established method for assessing cardiac function. However, limited data are available to evaluate ventricular synchrony with ERNA. The aim of this study was to assess the variability and accuracy of ERNA to evaluate ventricular synchrony by means of phase images in healthy individuals and to compare them with a group of subjects with left bundle-branch block (interventricular dyssynchrony, LBBB) and with a group of patients with nonischemic, dilated cardiomyopathy (DCM) (inter- and intraventricular dyssynchrony). METHODS: The population was divided into groups as follows: group 1 included 22 healthy subjects, group 2 included 11 patients with LBBB and normal left ventricular ejection fraction (LVEF), and group 3 included 14 DCM patients with LVEF <35% and LBBB. Interventricular synchrony was measured as the difference between LV mean phase angle (mPA) and RV mPA (LV-RV mPA). Intraventricular synchrony for each ventricle was measured as the standard deviation (SD) of the RV mPA and LA mPA blood pools. RESULTS: Intra- and interobserver correlation coefficients were high for both inter- and intraventricular synchrony parameters. Area under the curve (AUC) was 0.98 for LV-RV mPA (p <0.001; 95% CI: 0.947-1.0). A cutoff value of 10 degrees yielded 96% sensitivity and 99% specificity to identify interventricular dyssynchrony. AUC was high for SD RV mPA and SD LV mPA (AUC = 1.0, p <0.001; 95% CI: 1.0-1.0 and AUC = 0.99, p <0.001; 95% CI: 0.979-1.0). A cutoff value of 22 degrees for SD LV mPA yielded 100% sensitivity and 100% specificity to identify LV intraventricular dyssynchrony. A cutoff value of 20 degrees for SD RV mPA yielded 100% sensitivity and 99% specificity to identify RV intraventricular dyssynchrony. CONCLUSIONS: ERNA is an accurate and highly reproducible technique for evaluation of ventricular function and synchrony.