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Objectives: We investigated the epicardial fat volume (EFV) between patients with normal perfusion and reversible perfusion abnormalities in the myocardial perfusion scintigraphy (MPS) in patients with suspected coronary artery disease (CAD). In addition, we aimed to investigate the relationship of automated analysis parameters obtained in the MPS SPECT examination with EFV. Methods: A total of 295 patients (182 F, 113 M) who underwent MPS in our unit with the suspicion of CAD in the last 1 year and who had a recent thorax CT examination were included. EFV measurement in CT scans was done with Invesalius software. MPS was performed in all patients with a one-day stress and rest imaging protocol. In the stress study, imaging was performed approximately 30-45 minutes after intravenous injection of ~12 mCi Tc99m Sestamibi. Rest study imaging was performed approximately 30-60 minutes after intravenous injection of ~25 mCi Tc99m Sestamibi. Results: Median EFV was 53.00 ml (interquartile range: 23 ml, range 17-238 ml) in patients with normal MPS, and 62.00 ml in patients with myocardial ischemia on scintigraphy (interquartile range: 53 ml, range: 25-207 ml). The EFV value was statistically significantly higher in patients with reversible ischemia on MPS compared to patients with normal scintigraphy findings (p < 0.001). There was a statistically significant, low, and positive correlation between EFV and summed difference score (SDS) values (p = 0.002, r = 0.178). Conclusions: The EFV value was significantly higher in patients with reversible ischemia on MPS compared to patients with normal scintigraphy findings. Also there was a statistically low and positive correlation between EFV and SDS values. The automatic calculation of the EFV value during this examination may be a good additional parameter to detect the presence of ischemia.

PURPOSE: The purpose of this study was to determine the lowest Tl-201 dose that does not reduce the image quality of myocardial perfusion SPECT (MPS) by Poisson resampling simulation. METHODS: One hundred and twelve consecutive MPS data from patients with suspected or known coronary artery disease were collected retrospectively. Stress and rest MPS data were resampled using the Poisson method with 33%, 50%, 67%, and 100% count settings. Two nuclear medicine physicians assessed the image quality of reconstructed data visually by giving grades from − 2 to + 2. The summed stress score (SSS), summed rest score (SRS), and summed difference score (SDS) were obtained on the workstation. Image quality grades and semi-quantitative scores were then compared among these resampled images. RESULTS: The proportions of “adequate” image quality were 0.48, 0.75, 0.92, and 0.96 for the groups of images with 33%, 50%, 67%, and 100% data, respectively. The quality of the resampled images was significantly degraded at 50% and 33% count settings, while the image quality was not different between 67 and 100% count settings. We also found that high body mass index further decreased image quality at 33% count setting. Among the semi-quantitative parameters, SSS and SRS showed a tendency to increase with a decline in count. CONCLUSION: Based on the simulation results, Tl-201 dose for MPS can be reduced to 74 MBq without significant loss of image quality. However, the SSS and SRS can be changed significantly, and it needs to be further verified under the different conditions.

AIMS The study aimed to investigate whether additional prone imaging delivers comparable results to supine imaging with low-dose computed tomography (CT) attenuation correction (CTAC) in cadmium, zinc and telluride (CZT) myocardial perfusion imaging. METHODS AND RESULTS Thirty-four patients with an indication for myocardial perfusion imaging were studied with a CZT camera in the supine and then prone position. Furthermore, a low-dose CT was acquired. Three data sets were reconstructed and considered for analysis: (1) supine CZT, (2) supine CZT with CTAC and (3) supine CZT with additional prone CZT. Based on 17-segment polartomograms, we compared radiopharmaceutical uptake percentage, summed stress score (SSS), summed rest score (SRS), summed difference score (SDS), total ischemic and scarred segments, and finally scan classification and clinical decision-making. SSS of supine/supine-CTAC/supine-prone was 341/229/253 (P

BACKGROUND Sequential assessment using CT coronary angiography (coronary CT) and nuclear myocardial perfusion imaging (MPI) is considered an anatomical and functional evaluation of coronary artery disease (CAD). However, there can be unexpected radiation exposure. Hybrid MPI with stress-only nuclear MPI and rest CT-MPI using coronary CT may contribute to reducing the radiation dose in sequential assessment with nuclear MPI after coronary CT. We analyzed the diagnostic performance and total radiation dose of hybrid MPI for detection of significant CAD compared with sequential assessment using nuclear MPI after coronary CT.Methods and Results:The results for 101 patients who underwent coronary CT, nuclear MPI and invasive coronary angiography within 3 months of all imaging were analyzed. We calculated the summed difference score (SDS) from standard nuclear MPI and hybrid SDS from hybrid MPI, which revealed myocardial ischemia. The diagnostic performance of SDS and hybrid SDS for detecting significant CAD was analyzed using receiver-operating characteristic (ROC) curve analysis. We also compared the total radiation dose of both methods. The area under the ROC curve was not different between SDS and hybrid SDS (0.901 and 0.815, P=0.079). Total radiation dose of hybrid MPI was significantly lower than standard nuclear MPI with CT angiography (4.62 mSv vs. 9.72 mSv, P

Background This study compared the diagnostic value of myocardial perfusion imaging (MPI) between the rest-stress 99 mTc-tetrofosmin protocol (Tc/Tc protocol) and simultaneous acquisition rest 99 mTc-tetrofosmin/stress 201Tl dual-isotope protocol (SDI protocol) with a semiconductor camera.Methods and Results: We retrospectively studied 147 patients who underwent stress MPI using a cadmium-zinc-telluride camera and invasive coronary angiography within a 3-month interval. The Tc/Tc and SDI protocols were used in 59 and 88 patients, respectively. The sensitivity, specificity, and accuracy of the summed difference score in per-patient analysis were 56%, 85%, and 69%, respectively, for the Tc/Tc protocol and 89%, 82%, and 85%, respectively, for the SDI protocol. The area under the receiver operating characteristic curve was significantly better for the SDI than Tc/Tc protocol for the left anterior descending artery (0.836 vs. 0.674; P=0.0380), the left circumflex artery (0.754 vs. 0.599; P=0.0441), and in per-patient analysis (0.875 vs. 0.707; P=0.0135). There was no significant difference in the diagnostic accuracy of the summed stress score for any vessel or in per-patient analysis between the 2 protocols. Conclusions The SDI protocol had a higher diagnostic accuracy for the detection of coronary ischemia than the Tc/Tc protocol.

Guidelines propose different rest–stress activity ratios (RSAR) for one-day stress-first SPECT myocardial perfusion imaging (MPI), but evidence is limited. Our aim was to determine and validate the minimal RSAR resulting in the same diagnostic outcome in one-day stress-first SPECT MPI. Forty-seven patients referred for rest after stress CZT-SPECT/CT MPI were prospectively included. Rest acquisitions were performed 3 h after stress. In addition to the stress and rest acquisitions, the first 22 patients underwent an additional acquisition prior to the rest injection to determine the remaining stress activity. Next, we simulated six RSARs varying from 1.0 to 3.5 in both patients and a phantom and compared the images to those using the reference RSAR of 4.0. Differences in summed difference score (SDS) >2 or ischemic defect interpretation were considered to significantly influence diagnostic outcome. After deriving the minimal RSAR, it was validated in 25 additional patients by comparing it to a RSAR of 4.0. After 3 h only 26% of the stress activity was still present in the myocardium. SDS differences >2 were found in one (4%) patient using RSAR of 3.5, 2.5 and 2.0, in three (12%) using 1.5 and in five (20%) using SRAR of 1.0. These results were consistent with the phantom study showing SDS differences >2 for RSARs ≤1.5 and with the visual interpretation which showed an increased number of deviating scans for RSAR 1.0. Validating the RSAR of 2.0 resulted in a different SDS in one patient (SDS of 30 versus 11). Moreover, two scans were interpreted as ischemic instead of normal when using RSAR 2.0 and in two other scans the opposite was the case. A RSAR of 2.0 in one-day stress-first MPI SPECT seems sufficient to obtain accurate diagnostic outcomes and is therefore recommended to reduce radiation exposure.

To evaluate the interplay between myocardial ischaemic burden and poststress left ventricular (LV) systolic and diastolic abnormalities in patients with suspected or known coronary artery disease (CAD). A total of 471 patients underwent myocardial perfusion imaging by cadmium-zinc-telluride scintigraphy and coronary angiography. A fast imaging protocol was used with stress imaging performed 10 – 15 min after tracer injection. The summed difference score (SDS) and the percent stress-to-rest ratios for LV ejection fraction and peak filling rate (PFR), measures of stress-induced systolic and diastolic impairment, were computed from scintigraphic images. A SDS of >3 was considered abnormal and >7 a marker of moderate-to-severe ischaemia. Of the 471 patients, 321 (68 %) showed significant CAD in one (27 %), two (23 %) or three (18 %) vessels. The extent of CAD associated with gradual alterations in SDS (P

Aims To evaluate the impact of diabetes mellitus (DM) on the accuracy of myocardial perfusion scintigraphy (MPS) in detecting coronary artery disease (CAD). Methods and results Two hundred and sixteen patients with DM and 432 matched controls were submitted to MPS on a dedicated cardiac camera equipped with cadmium-zinc-telluride (CZT) detectors and coronary angiography. Exercise stress was performed in 442 (68%) patients, while the remainders underwent vasodilator stress. Exercise level was determined as the percentage of the predicted maximal workload that was attained (%Wattmax). The summed difference score was derived from CZT images. A coronary stenosis >70% was considered obstructive. The prevalence of obstructive CAD was 59.7% in patients with DM and 56.2% in controls (P = NS). The accuracy of MPS in detecting CAD was similar in patients with and without DM [area under the ROC curve (AUC) 0.77 vs. 0.78, P = NS]. An interaction between the accuracy of MPS and cardiac stress-protocol was revealed. In fact, in patients with DM exercise stress CZT had a lower accuracy than vasodilator-stress (AUC 0.70 vs. 0.89, P

To compare the outcomes among patients treated by complete coronary revascularization (CCR) or incomplete coronary revascularization (ICR) and no coronary revascularization (NCR) by myocardial perfusion imaging (MPI), as well as to evaluate the impact of severity of ischemia on patients with coronary artery disease (CAD) by different therapy strategies.Using myocardial ischemia severity determined by MPI guiding treatment strategies for CAD patients still lacks strong clinical evidences.Consecutive patients (N = 286) underwent clinical stress-rest SPECT MPI and were retrospectively followed-up. For assessment of outcome of treatment, all patients were classified into three groups (CCR, ICR, and NCR), and further divided into two subgroups as mild ischemia ( 10% ischemic myocardium) and moderate-severe ischemia (≥ 10% ischemic myocardium). All-cause death was defined as the primary endpoint, and the composite of deaths, nonfatal myocardial infarction, and repeat revascularization (MACE) as the secondary endpoint.Two-hundred eighty-six patients were followed-up for 46 ± 21 months. Thirty deaths and 65 MACEs were recorded. Patients treated by revascularization had significantly lower MACE (P .001) but not mortality (P = .158) than patients treated by NCR. Outcomes of CCR related to mortality rate were greater than ICR and NCR (death: P = .019, MACE: P .001). In patients with moderate-severe ischemia, CCR showed improved outcomes than ICR and NCR (death: P = .034; and MACE: P .001). In patients with mild ischemia, the outcomes of CCR, ICR, and NCR had no significant difference (P .05). Multivariate regression Cox analysis revealed that summed difference score [death: HR 1.09 (1.03, 1.15), P = .004] was an independent risk factor and CCR was an independent negative predictor [death: HR 0.31 (0.12, 0.81), P = .017; MACE: HR 0.30 (0.16, 0.57), P .001].Outcomes of patients treated by CCR were most likely more promising in comparison with treatment of ICR and NCR, especially when patients had over 10% ischemic myocardium.

Both the myocardial perfusion pattern and myocardial blood flow (MBF) are used to assess patients with suspected coronary artery disease (CAD). The aim of this study was to compare the perfusion pattern (using the summed difference score [SDS]) to MBF in a consecutive group of patients undergoing PET/CT with 13 N-ammonia (13NH3). 47 consecutive patients, aged 65 ± 12 years (42 men) with known or suspected CAD, underwent vasodilator stress/rest PET/CT with 13NH3 for clinical indications. The SDS was determined by a commercially available software based on a 17-segment model. MBF was measured at rest and during hyperemia by dynamic acquisition and single-compartment model analysis. From the rest and stress MBF, the absolute difference (stress-rest) in myocardial blood flow defined as difference in myocardial blood flow (DMBF) was derived. There were no significant differences between patients with no ischemia (SDS ≤ 1) and those with ischemia (SDS > 1) in CFR (2.84 ± 0.73 vs 2.63 ± 0.89, P = NS) and DMBF (1.34 ± 0.45 vs 1.24 ± 0.53 mL·minute−1·g−1, P = NS). There were however significant regional differences (141 different vascular territories in 47 patients) between these two groups (CFR: 2.84 ± 0.95 vs 2.16 ± 0.57, P

A relationship between left ventricular (LV) contractile impairment and myocardial perfusion abnormalities has been suggested. Three-hundred and thirty-seven patients underwent myocardial perfusion imaging at CZT and coronary angiography. On scintigraphic images, the summed difference score (SDS) and LV-ejection fraction (EF) were computed. Patients were categorized as follows: Group-1 (LV-EF

PurposePatients with normal stress myocardial perfusion imaging (MPI) results generally have an excellent prognosis with

A novel antithrombotic agent, lumbrokinase, was evaluated in this pilot study for its efficacy in the treatment of symptomatic stable angina.This was a single-armed cohort study.The study was conducted at the National Cardiovascular Center, Harapan Kita, Jakarta, Indonesia.The study comprised 10 patients who had coronary artery disease and stable angina and who consented to the trial.Patients were treated with oral lumbrokinase for 30 consecutive days in addition to their standard medical therapy.Stress technetium-99m sestamibi myocardial perfusion imaging (MPI) was performed before and at the conclusion of the active treatment period. The degree and extent of inducible ischemia observed on the myocardial perfusion images were evaluated using the previously validated semiquantitative indices (Summed Stress Score and Summed Difference Score).Following active treatment, the mean Summed Stress Score and Summed Difference Score deceased by 39% and 37%, respectively. The anginal symptom was ameliorated in 6 of 10 patients. No adverse reaction including major or minor bleeding was observed.This paper represents the first description of the use of oral lumbrokinase in the treatment of chronic coronary artery disease with objective assessment using MPI. Oral lumbrokinase improves regional myocardial perfusion in patients with stable angina.

Multidetector-row computed tomography (MDCT) has become one of the major tools in diagnosing and evaluating patients with coronary artery disease in recent years. In selected patients, MDCT has been shown to provide more reliable accuracy in detection of stent patency than invasive coronary angiography. Chiou et al reported a delicate infarcted myocardium at-risk score. According to their results, the MDCT-based myocardium at-risk score had a good correlation with the thallium 201 ST-segment elevation myocardial infarction-based summed difference score (r = 0.841, P < 0.001). They claimed that dual-phase MDCT is useful in detecting different patterns of obstructive lesions and the extent of myocardium at risk. In this commentary, we discuss the current status of the clinical application of MDCT in patients with myocardial infarction in relation to evaluating the myocardial perfusion defect, detecting reversible myocardial ischemia, assessing myocardial viability, estimating target lesion restenosis, and calculating of fractional flow reserve from MDCT.

The determinants of an ischemic electrocardiographic (ECG) response in patients with exercise-induced ischemia on single-photon emission computed tomography (SPECT) remain poorly defined. Specifically, it is unknown whether the occurrence of an ischemic ECG response is related to the extent and/or severity of SPECT ischemia. Among 3,294 patients who underwent exercise SPECT using a rest thallium-201/exercise Tc-99m sestamibi protocol, 699 (21%) patients had myocardial ischemia defined as summed difference score (SDS) ≥2. The extent of SPECT ischemia was further defined as the total number of segments with difference score ≥1, and severity of ischemia as the largest difference score among all segments. Patients with ischemic ECG changes (n = 315) were significantly older and had a significantly greater prevalence of hyperlipidemia. SDS (7.4 ± 2.2 vs 4.7 ± 1.9, P

Some studies reported that 99mTc-MIBI may redistribute in ischaemic myocardium and this phenomenon may have potential role for better assessment of viability by delayed 99mTc-MIBI imaging. Some studies also suggested that infusion of low dose dobutamine during delayed imaging may enhance the value of 99mTc-MIBI imaging for evaluation of viability. The aim of this study is to determine whether the observed changes of perfusion defects on delayed images are caused by early radiotracer redistribution or as a result of reversal partial volume effect secondary to inotropic stimulation. Patients, methods: 89 patients with angiographically proven coronary artery disease (CAD) were enrolled in this randomized clinical trial study. In all cases, gated-SPECT images were obtained 60 minutes after stress with dipyridamole injection. Subsequently the patients were randomly allocated in two groups and the second imaging was performed at 120th minute during low dose dobutamine (dobutamine group; 45 cases) or placebo infusion (placebo group; 44 cases). Difference between summed stress score of the first (SSS1) and second (SSS2) stress images (DSSS) was considered as a marker of reversibility in single-injection double-acquisition (SIDA) protocol. Also summed difference score (SDS) was recorded as a marker of reversibility in standard stress/rest, double-injection double-acquisition (DIDA) protocol. DSSS of the two studied groups were compared. Also the correlation and agreement between DSSS and SDS were analyzed. Results: A significant difference was found between SSS1 (median 15, range 0–48) and SSS2 (median 11, range 0–42) in total patients (p < 0.0001). A significant correlation was noted between DSSS and SDS in dobutamine group (r = 0.58, p = 0.002) as well as in placebo group (r = 0.57, p < 0.0001). Considering DIDA protocol as a standard reference method, the influence of dobutamine infusion was not shown to be significantly different from the placebo effect on the magnitude of fixed or reversible perfusion defects in SIDA protocol. Conclusion: The changes in the magnitude of the perfusion defects may occur in the first hours of 99mTc-MIBI injection in the stress phase imaging. These changes correlate well and are in agreement with perfusion improvement on the rest images. This phenomenon may be independent of improvement in myocardial function, in more delayed imaging or following inotropic augmentation, and thus is likely due to 99mTc-MIBI redistribution. This may open new technical and clinical aspects and potentials for 99mTc-MIBI imaging.

The impact of arrhythmias on the evaluation of perfusion data from myocardial gated SPECT has been assessed by comparing arrhythmic patients with nonarrhythmic patients or by simulating rhythm disturbances. Whether gating-related artifacts may have a clinically relevant influence on the evaluation of perfusion in atrial fibrillation (AF) patients is still uncertain. Recently, collection of nongated and gated datasets during the same SPECT acquisition has become possible. The aim of this study was to examine the difference in myocardial perfusion between simultaneously acquired gated and nongated SPECT data in AF patients.In 44 consecutive AF patients who underwent myocardial perfusion SPECT for standard clinical indications, both a gated and a nongated study were simultaneously acquired. Perfusion was estimated in a masked manner on a 20-segment model using an established scoring scheme.Agreement was good between the gated and nongated perfusion scores on a segment basis; the agreement for resting scores was the highest, with those for stress and difference scores being lower (Spearman rho = 0.82, 0.74, and 0.55, respectively). On a patient basis, a similar trend was seen in summed resting scores (rho = 0.911), summed stress scores (rho = 0.779), and summed difference scores (rho = 0.596). When summed stress and summed difference data were grouped by severity class (normal, mild abnormality, moderate abnormality, and severe abnormality), agreement decreased from rho = 0.818, kappa = 0.639, for summed stress score to rho = 0.549, kappa = 0.367, for summed difference score. The severity class of inducible ischemia changed in 17 patients (39%) if a (summed) gated image was used instead of a standard nongated perfusion image.AF may have a clinically relevant impact on summed gated perfusion images, compared with images simultaneously obtained without gating in the same patients. Therefore, acquisition of a nongated SPECT study is mandatory for accurate assessment of myocardial perfusion in AF patients.

To examine the susceptibility to myocardial ischemia with mental stress in patients who have coronary artery disease and normal left ventricular (LV) function versus those who have impaired LV function, we examined 58 patients who had coronary artery disease, including 22 who had normal LV function (ejection fraction/=50%), 16 who had mild to moderate LV dysfunction (ejection fraction 30% to 50%), and 20 who had severe LV dysfunction (ejection fraction/=30%) and underwent bicycle and mental stress testing with myocardial perfusion scintigraphy on consecutive days in random order. Ischemia was assessed based on summed difference scores in regional rest versus stress myocardial perfusion and defined as a summed difference score3. At comparable double products across the 3 groups, ischemia was induced with mental stress more frequently in patients who had severe LV dysfunction (50%) than in those who had normal LV function (9%; p0.01). The frequency of exercise-induced ischemia was different only between those who had mild/moderate LV dysfunction and those who had normal LV function (56% vs 18%, respectively, p0.05). The pattern of mental stress versus exercise ischemia differed between groups (p0.02): there was a higher prevalence of mental stress ischemia versus exercise ischemia in patients who had severe LV dysfunction (p = 0.06), a marginally higher prevalence of exercise versus mental stress ischemia in those who had moderate LV dysfunction (p = 0.07), and no difference in mental stress versus exercise ischemia in those who had normal LV function. Thus, at comparable double products during mental stress and similar extent of coronary artery disease, ischemia with mental stress was induced more frequently in patients who had severe LV dysfunction than in those who had normal LV function. These data suggest that mental stress ischemia may be of particular clinical importance in patients who have coronary artery disease and LV dysfunction.

1817 Objectives The prevalence of left ventricular mechanical dyssynchrony (LVMD) in stable angina pectoris (AP) has not been fully clarified. The aim of this study was to assess the presence and severity of LVMD in stable AP. Methods A total of 201 patients (age 69 ± 11, 137 males) with suspected ischemic heart disease underwent stress/rest gated myocardial perfusion SPECT (GMPS). For the evaluation of LVMD, histogram bandwidth (HBW) and phase standard deviation (PSD) were determined by GMPS using phase analysis. LVMD at stress and rest were compared among three groups: 103 normal patients (NG) [summed stress score (SSS) 50 %], 54 patients with ischemia (IG) [SSS > 3, summed difference score (SDS) > 1, and summed rest score (SRS) 3 and SDS Results The measured LVMD parameters (HBW and PSD) in NG, IG, and pMIG are summarized in the figure. At stress, both HBW and PSD in IG were significantly greater than those in NG (p Conclusions In patients with stable AP, LVMD was demonstrated to be enhancement at stress, and was found to be detectable equally well with prior MI

Background: Quantitative gated SPECT (QGS) is useful in evaluating left ventricular ejection fraction (LVEF), end systolic volume (ESV), and end diastolic volume (EDV). Less is known regarding factors potentially associated with differences in LVEF and volumes obtained from QGS at rest and post-stress. Methods: Using a 2-day protocol, SPECT data was obtained at rest and post-stress with high dose (25 mCi) Tc-99m sestamibi bolus. LVEF, ESV, and EDV were derived from automated Cedars-Sinai QGS software. Of 100 patients prospectively studied, 92 studies were technically adequate. Delta LVEF was defined as QGS rest EF minus QGS post-stress LVEF. Delta ESV and EDV were similarly defined. Results: (See table). LVEF, ESV, and EDV rest and post-stress were highly correlated. LVEF and EDV were higher at rest than post-stress. Summed difference score (SDS) >0 was significantly associated with increased delta LVEF (p=0.02). Mean LVEF post-stress in ischemic patients was 55.0% vs 61.1% in nonischemic patients (p=0.01). SDS=0 was associated with increased delta EDV (p