Comparison of the dyssynchrony parameters recorded with gated SPECT in ischemic cardiomyopathy according to their repeatability at rest and to their ability to detect a synchrony reserve under dobutamine infusion.

BACKGROUND: This study aimed to determine whether the repeatability of dyssynchrony assessment using gated myocardial perfusion SPECT (GSPECT) allows the detection of synchrony reserve during low-dose dobutamine infusion. METHODS AND RESULTS: Sixty-one patients with ischemic cardiomyopathy and LV ejection fraction < 50% were prospectively included in 10 centers. Each patient underwent two consecutive rest GSPECT with 99mTc-labeled tracer (either tetrofosmin or sestamibi) to assess the repeatability of LV function and dyssynchrony parameters, followed by a GSECT acquisition during low-dose dobutamine infusion. LV dyssynchrony was assessed using QGS software through histogram bandwidth (BW), standard deviation of the phase (SD), and entropy. Repeatability was assessed with Lin's concordance correlation coefficient (CCC). Entropy showed a higher CCC (0.80) compared to BW (0.68) and SD (0.75). On average, dobutamine infusion yielded to improve both BW (P = .049) and entropy (P = .04) although significant improvements, setting outside the 95% confidence interval of the repeatability analysis, were documented in only 6 and 4 patients for BW and entropy, respectively. CONCLUSIONS: A synchrony reserve may be documented in patients with ischemic cardiomyopathy through the recording of BW and entropy with low-dose dobutamine GSPECT, with the additional advantage of a higher repeatability for entropy.

Routine evaluation of left ventricular function using CZT-SPECT, with low injected activities and limited recording times.

PURPOSE: Gamma-cameras, with Cadmium-Zinc-Telluride (CZT) detectors, allow to perform myocardial perfusion imaging (MPI) with limited injected activities and recorded times. This study aimed at determining whether the routine assessment of left ventricular (LV) function with such limited counts protocols compares well with reference values from cardiac MRI. METHODS: The study included patients who have undergone cardiac MRI and an MPI routinely planned on a CZT camera with a low-dose protocol (120 MBq of Sestamibi for stress and 360 MBq at rest for 75 kg body weight), while targeting the recording of only 500 myocardial kcounts in order to limit the recording times (<10 minutes for stress, <4 minutes for rest). SPECT images were reconstructed with a method maintaining rather high spatial (8 mm) and temporal (16 frames/cycle) resolutions. RESULTS: Seventy-six patients were included, and mean effective dose was 3.5 ± 1.7 mSv for the total MPI protocol. Correlations between CZT-SPECT and MRI were good to excellent for ejection fraction (r 2 = 0.77), end-diastolic (r 2 = 0.88) and end-systolic (r 2 = 0.93) volumes, and the analysis of segmental contractility correlated well between the two techniques (kappa score = 0.72 ± 0.02). CONCLUSION: LV function, assessed on a CZT camera with low injected activities and limited recording times, correlates well with the reference assessment from cardiac MRI.

Low-dose dual-isotope procedure planed for myocardial perfusion CZT-SPECT and assessed through a head-to-head comparison with a conventional single-isotope protocol.

PURPOSE OF THE REPORT: This study aimed at assessing an original low-dose dual-isotope procedure in which the abnormal stress Tc-99m Sestamibi SPECT is followed by rest Tl-201 SPECT, along with a head-to-head comparison with a single-isotope procedure. METHODS AND RESULTS: One hundred two patients, referred for a low-dose stress-SPECT with Sestamibi (123 ± 20 MBq) on a CZT camera and for whom a rest Sestamibi SPECT was warranted, had an additional Tl-201 rest-SPECT (52 ± 5 MBq) between stress and rest Sestamibi SPECT recordings. Tl-201 images were processed for spill-over and scatter corrections, and uptake differences with stress Sestamibi SPECT were analyzed: (1) for rest acquisitions from Tl-201 (dual-isotope procedure) and from Sestamibi (single-isotope procedure) and (2) in segments for which a diagnosis of ischemia, infarct, or normal perfusion was achieved. Mean effective dose was 8.3 mSv for dual-isotope but would decrease to 5.7 mSv for an expected rate of 37% of patients for whom rest-SPECT is not warranted. After a further background correction of Tl-201 images, the rest-stress difference in myocardial uptake was equivalent between dual- and single-procedures for identifying ischemic segments (respective areas-under-curves: 0.83 ± 0.03 and 0.81 ± 0.03). CONCLUSION: This original dual-isotope procedure provides acceptable radiation doses and consistent results, as compared with conventional single-isotope.

Stress-first protocol for myocardial perfusion SPECT imaging with semiconductor cameras: high diagnostic performances with significant reduction in patient radiation doses.

PURPOSE: Effective doses of 14 mSv or higher are currently being attained in patients having stress and rest myocardial perfusion imaging (MPI) single photon emission computed tomography (SPECT) performed on the same day with conventional protocols. This study aimed to assess the actual reduction in effective doses as well as diagnostic performances for MPI routinely planned with: (1) high-sensitivity cadmium zinc telluride (CZT) cameras, (2) very low injected activities and (3) a stress-first protocol where the normality of stress images may lead to avoiding rest imaging. METHODS: During a 1-year period, 2,845 patients had MPI on a CZT camera, a single-day stress-first protocol and low injected activities (120 MBq of (99m)Tc-sestamibi at stress for 75 kg body weight and threefold higher at rest). The ability to detect > 50% coronary stenosis was assessed in a subgroup of 149 patients who also had coronary angiography, while the normalcy rate was assessed in a subgroup of 128 patients with a low pretest likelihood of coronary artery disease (<10%). RESULTS: Overall, 33% of patients had abnormal MPI of which 34% were women and 34% were obese. The mean effective doses and the percentage of exams involving only stress images were: (1) 3.53 ± 2.10 mSv and 37% in the overall population, (2) 4.83 ± 1.56 mSv and 5% in the subgroup with angiography and (3) 1.96 ± 1.52 mSv and 71 % in the low-probability subgroup. Sensitivity and global accuracy for identifying the 106 patients with coronary stenosis were 88 and 80%, respectively, while the normalcy rate was 97 %. CONCLUSION: When planned with a low-dose stress-first protocol on a CZT camera, MPI provides high diagnostic performances and a dramatic reduction in patient radiation doses. This reduction is even greater in low-risk subgroups with high rates of normal stress images, thus allowing the mean radiation dose to be balanced against cardiac risk in targeted populations.

Factors affecting the myocardial activity acquired during exercise SPECT with a high-sensitivity cardiac CZT camera as compared with conventional Anger camera.

PURPOSE: Injected doses are difficult to optimize for exercise SPECT since they depend on the myocardial fraction of injected activity (MFI) that is detected by the camera. The aim of this study was to analyse the factors affecting MFI determined using a cardiac CZT camera as compared with those determined using conventional Anger cameras. METHODS: Factors affecting MFI were determined and compared in patients who had consecutive exercise SPECT acquisitions with (201)Tl (84 patients) or (99m)Tc-sestamibi (87 patients) with an Anger or a CZT camera. A predictive model was validated in a group of patients routinely referred for (201)Tl (78 patients) or (99m)Tc-sestamibi (80 patients) exercise CZT SPECT. RESULTS: The predictive model involved: (1) camera type, adjusted mean MFI being ninefold higher for CZT than for Anger SPECT, (2) tracer type, adjusted mean MFI being twofold higher for (201)Tl than for (99m)Tc-sestamibi, and (3) logarithm of body weight. The CZT SPECT model led to a +1 ± 26% error in the prediction of the actual MFI from the validation group. The mean MFI values estimated for CZT SPECT were more than twofold higher in patients with a body weight of 60 kg than in patients with a body weight of 120 kg (15.9 and 6.8 ppm for (99m)Tc-sestamibi and 30.5 and 13.1ppm for (201)Tl, respectively), and for a 14-min acquisition of up to one million myocardial counts, the corresponding injected activities were only 80 and 186 MBq for (99m)Tc-sestamibi and 39 and 91 MBq for (201)Tl, respectively. CONCLUSION: Myocardial activities acquired during exercise CZT SPECT are strongly influenced by body weight and tracer type, and are dramatically higher than those obtained using an Anger camera, allowing very low-dose protocols to be planned, especially for (99m)Tc-sestamibi and in non-obese subjects.

Comparison between stress myocardial perfusion SPECT recorded with cadmium-zinc-telluride and Anger cameras in various study protocols.

PURPOSE: The results of stress myocardial perfusion SPECT could be enhanced by new cadmium-zinc-telluride (CZT) cameras, although differences compared to the results with conventional Anger cameras remain poorly known for most study protocols. This study was aimed at comparing the results of CZT and Anger SPECT according to various study protocols while taking into account the influence of obesity. METHODS: The study population, which was from three different institutions equipped with identical CZT cameras, comprised 276 patients referred for study using protocols involving (201)Tl (n = 120) or (99m)Tc-sestamibi injected at low dose at stress ((99m)Tc-Low; stress/rest 1-day protocol; n = 110) or at high dose at stress ((99m)Tc-High; rest/stress 1-day or 2-day protocol; n = 46). Each Anger SPECT scan was followed by a high-speed CZT SPECT scan (2 to 4 min). RESULTS: Agreement rates between CZT and Anger SPECT were good irrespective of the study protocol (for abnormal SPECT, (201)Tl 92 %, (99m)Tc-Low 86 %, (99m)Tc-High 98 %), although quality scores were much higher for CZT SPECT with all study protocols. Overall correlations were high for the extent of myocardial infarction (r = 0.80) and a little lower for ischaemic areas (r = 0.72), the latter being larger on Anger SPECT (p < 0.001). This larger extent was mainly observed in 50 obese patients who were in the (201)Tl or (99m)Tc-Low group and in whom stress myocardial counts were particularly low with Anger SPECT (228 ± 101 kcounts) and dramatically enhanced with CZT SPECT (+279 ± 251 %). CONCLUSION: Concordance between the results of CZT and Anger SPECT is good regardless of study protocol and especially when excluding obese patients who have low-count Anger SPECT and for whom myocardial counts are dramatically enhanced on CZT SPECT.

Aortic inflammation, as assessed by hybrid FDG-PET/CT imaging, is associated with enhanced aortic stiffness in addition to concurrent calcification.

PURPOSE: To analyse the relationship between: (i) aortic pulse wave velocity (PWV), an index of aortic stiffness with strong prognostic significance, and (ii) aortic calcification and inflammation, which were quantified by hybrid imaging with X-ray computed tomography (CT) and (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET). METHODS: Central aortic (carotid-femoral) and peripheral (carotid-brachial and femoral-tibial) PWV were recorded in 26 patients, who had been routinely referred for dual FDG-PET/CT imaging. RESULTS: In univariate analyses, central aortic PWV was strongly linked to the volume of calcifications (VCa) and an enhanced FDG activity, when determined by averaging standardized uptake values (SUV(max)). By multivariate stepwise analysis including age and gender, both VCa (p < 0.0001) and SUV(max) (p < 0.01) were significant determinants of PWV explaining 61% and 11% of its variability. CONCLUSION: Aortic inflammation, assessed by hybrid FDG-PET/CT imaging, is associated with an enhanced aortic stiffness, in addition to the concurrent impact of calcifications.

Residual stress ischaemia is associated with blood markers of myocardial structural remodelling.

BACKGROUND: Long-term prognosis of coronary artery disease (CAD) patients is worsened when stress ischemia persists on treatment, but the relationship with adverse cardiac remodelling had never been investigated. AIM: To analyze changes in blood markers of fibrosis in patients with chronic CAD exhibiting exercise ischaemia. METHODS: Circulating markers of collagen: (i) turnover (amino-terminal propeptide of collagen-III [PIIINP]) and (ii) degradation (matrix metalloproteinase 1 [MMP-1]), were obtained in 139 CAD patients referred for exercise 201Tl-SPECT. RESULTS: In the 57 patients who had SPECT-ischaemia, PIIINP was higher (4.3+/-2.9 microg L-1 vs. 3.1+/-1.5 microg L-1, p=0.002) and MMP-1 lower (3.8+/-2.1 microg L-1 vs. 4.7+/-2.8 microg L-1, p=0.04) than in the 82 patients without SPECT-ischaemia. PIIINP was independently related to LV volume, SPECT-ischaemia and age, whereas MMP-1 was related to current treatment with ACEI and beta-blockers (p<0.05). In the 104 patients with a normal LV ejection fraction, only PIIINP was related to SPECT-ischaemia (4.1+/-2.2 microg L-1 vs. 3.1+/-1.5 microg L-1, p=0.01). CONCLUSION: In patients with chronic CAD, exercise ischaemia is associated with increased collagen-III turnover, independently of concomitant medications and even when LV ejection fraction is normal. Long-term, this increase might relate to adverse cardiac remodelling even when cardiac function is not clearly affected at baseline.

Exercise release of cardiac natriuretic peptides is markedly enhanced when patients with coronary artery disease are treated medically by beta-blockers.

OBJECTIVES: This study sought to identify determinants of the exercise rise in plasma levels of cardiac natriuretic peptides (NPs) in patients with coronary artery disease (CAD). BACKGROUND: During stress, there is a variable rise in the plasma level of NPs, but this rise frequently reaches levels that are known to lower the cardiac load and that thus might be beneficial to CAD patients. METHODS: Plasma venous concentrations of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) were determined at rest and peak exercise in 104 patients with chronic CAD who were referred to exercise thallium-201 ((201)Tl) single-photon emission computed tomography (SPECT) and radionuclide angiography. RESULTS: The extent of scarred myocardium by (201)Tl-SPECT and patient age were the best independent predictors of NP concentrations at rest, but also of increases in NP concentration during exercise (all p < 0.001). Moreover, beta-blocking treatment was an additional and strong independent predictor of the increase in NP concentrations at exercise (p < 0.001 for ANP; p = 0.001 for BNP). On average, exercise increases in NP concentrations were more than twice as high in patients with (n = 55) than in those without (n = 49) beta-blocker treatment (ANP: +49 +/- 63 vs. +22 +/- 25 ng/l, p = 0.01; BNP: +24 +/- 5 vs. +11 +/- 15 ng/l, p = 0.04), whereas NP concentrations at rest were equivalent in the two groups (ANP: 34 +/- 34 vs. 30 +/- 33 ng/l, p = NS; BNP: 85 +/- 152 vs. 57 +/- 101 ng/l, p = NS). CONCLUSIONS: Patients with chronic CAD exhibit much higher exercise releases of ANP and BNP when they are treated with beta-blockers. This enhanced secretion of potent vasodilating and natriuretic agents constitutes an original therapeutic mechanism for further protecting diseased hearts against stress.

OSEM reconstruction, associated with temporal fourier and depth-dependant resolution recovery filtering, enhances results from sestamibi and 201Tl 16-interval gated SPECT.

UNLABELLED: Gated SPECT recorded with 16 intervals determines left ventricular (LV) ejection fraction more accurately than does gated SPECT recorded with 8 intervals but produces higher image noise. This study aimed to assess the results from sestamibi and (201)Tl 16-interval gated SPECT when both signal-to-noise ratio and spatial resolution were enhanced with an original method of reconstruction. METHODS: Forty patients with coronary artery disease underwent (201)Tl and sestamibi 16-interval gated SPECT and, to be used as a reference, cardiac MRI. Assessments of global and regional LV function provided by ordered-subsets expectation maximization (OSEM) with depth-dependant resolution recovery and temporal Fourier filtering were compared with those from conventional filtered backprojection (FBP) previously optimized by screening various filter frequencies and various temporal smoothing levels. RESULTS: For both tracers, LV ejection fraction was determined best when the association of OSEM with depth-dependant resolution recovery was used alone, with temporal Fourier filtering, or with a slight 2-frame temporal smoothing: Mean absolute values of relative errors ranged from 3.2% to 3.6% (4.0%-7.9% for FBP), and coefficient correlation ranged from 0.91 to 0.93 (0.70-0.91 for FBP). Among these 3 reconstruction methods, the association of OSEM with depth-dependant resolution recovery with temporal Fourier filtering provided the highest signal-to-noise ratio, with mean increases of 54% for sestamibi and 80% for (201)Tl when compared with FBP, and the best analysis of segmental contractility, with exact agreement rates with MRI being 73% for (201)Tl and 79% for sestamibi. CONCLUSION: OSEM associated with temporal Fourier filtering and depth-dependant resolution recovery filtering enhances the LV function assessment provided by sestamibi and (201)Tl 16-interval gated SPECT and dramatically reduces image noise, a property that enhances and facilitates image interpretation.

Residual viability is a predictor of the perfusion enhancement obtained with the cell therapy of chronic myocardial infarction: a pilot multimodal imaging study.

PURPOSE: Up to now, there has been limited investigation into cell therapy in the chronic phase of severe myocardial infarction (MI), and many questions remain concerning the contribution of the engrafted cells and especially their impact on the reperfusion of MI areas, when assessed by objective quantitative imaging techniques. This randomized pilot SPECT, PET, and MRI study was aimed at assessing the effects of bone marrow mononuclear cells (BMNCs) when implanted in areas of severe and chronic MI. MATERIALS AND METHODS: Fourteen patients, who were referred for coronary artery bypass grafting (CABG) and in whom a screening MIBI-SPECT revealed severely damaged myocardium (<50% uptake under nitrate), were randomized between a cell therapy group (n = 7; CABG and injection of BMNCs within MI areas) and a control group (n = 7; CABG alone). RESULTS: The MI areas exhibited a posttherapeutic enhancement in the rest-uptake of MIBI in the cell therapy group [difference between 6-month control and baseline: +6.8% (5.4%), P = 0.03] but not in the control group [+1.0% (4.3%)]. However, in a per-patient analysis, this improvement was significant (> +9%) in only 3 cell therapy patients, whose MI areas before therapy had a higher FDG uptake [59% (9%) vs 38% (8%), P = 0.03] and a lower transmural extent at MRI [40% (6%) vs 73% (18%), P = 0.03] when compared with the other cell therapy patients. CONCLUSIONS: Perfusion enhancement, obtained with BMNCs in areas of chronic MI, might require an intermediate level of viability documented with FDG-PET and MRI and that totally necrotic MI seems refractory to this cell therapy technique.

Comprehensive MRI analysis of early cardiac and vascular remodeling in middle-aged patients with abdominal obesity.

OBJECTIVES: To determine, using a comprehensive MRI investigation, prevalence and vascular correlates of early left-ventricular concentric remodeling in middle-aged patients with abdominal obesity. Left-ventricular and vascular remodeling are commonly associated with hypertension, but little is known for abdominal obesity patients, a population with definite increase in cardiovascular risk and high rates of further developments of hypertension and of the metabolic syndrome. METHODS: Seventy middle-aged abdominal obesity patients (56 ±â€Š5 years, 49% women, 69% with body mass index > 30 kg/m), who had no additional cardiovascular risk factor except for untreated stage 1 hypertension (16%), and 40 controls underwent MRI for detecting concentric remodeling (increase in left-ventricular mass/end-diastolic volume ratio) and identifying potential determinants, including arterial compliance indexes [aortic pulse wave velocity and total arterial compliance (TAC)] and total peripheral vascular resistances (TPVRs). RESULTS: Twenty abdominal obesity patients (29%) had concentric remodeling (concentric remodeling+), whereas 50 did not (concentric remodeling-). Concentric remodeling+ patients were mostly men (85%), they frequently had stage 1 hypertension (45%) and few had left-ventricular hypertrophy (20%). When adjusted for sex, there was a step-by-step decline in TAC between controls (mean ±â€ŠSEM: 2.10 ±â€Š0.06 ml/mmHg), concentric remodeling- (1.82 ±â€Š0.06 ml/mmHg) and concentric remodeling+ (1.42 ±â€Š0.09 ml/mmHg, P < 0.005 for inter-group comparisons) and TPVRs were lower than controls for concentric remodeling- (14.7 ±â€Š0.5 vs. 16.8 ±â€Š0.5 ml/mmHg, P = 0.005) but not for concentric remodeling+ (17.5 ±â€Š0.7 mmHg/min per l). CONCLUSIONS: Concentric remodeling is frequently documented by MRI in the middle-aged men with abdominal obesity and in association with a decrease in TAC no longer counter-balanced by a decrease in TPVR, suggesting a remodeling from proximal to peripheral vasculature.

Arterial foci of F-18 fluorodeoxyglucose are associated with an enhanced risk of subsequent ischemic stroke in cancer patients: a case-control pilot study.

PURPOSE OF THE REPORT: Imaging of F-18 fluorodeoxyglucose (FDG) by positron emission tomography/computed tomography (PET/CT) hybrid systems allows detecting arterial FDG foci, which relate to inflammatory and presumably unstable atherosclerosis, and is increasingly used in cancer patients among whom many are at risk for ischemic events. However, the link between an enhanced arterial FDG uptake and subsequent ischemic events remains to be clearly established. This pilot study aimed at determining whether the prior arterial FDG uptake in cancer patients presenting a subsequent stroke was higher than that of stroke-free controls. MATERIALS AND METHODS: Patients referred to FDG PET/CT for conventional oncologic indications were retrospectively included and compared between: (i) 7 case-patients with subsequent hospitalizations for documented ischemic stroke and (ii) 16 event-free controls, matched to the case-patients according to age, gender, and cancer site. RESULTS: Stroke was related with previous arterial FDG foci when detected on the aortic arch (stroke patients, 86% vs. Controls, 31%; P = 0.03) and especially on carotid bifurcations (stroke patients, 71% vs. Controls, 6%; P = 0.006); and among the 5 case-patients with stroke from carotid territory, 4 (80%) had FDG foci on ipsilateral carotid bifurcations. CONCLUSIONS: This pilot study shows that the previous detection of FDG foci on aortic arch and especially on carotid bifurcations of cancer patients is associated with the risk of subsequent ischemic stroke. A further confirmation on larger populations is needed.

Multicompartmental analysis of late contrast enhancement in areas of myocardial infarction supplied by chronically occluded coronary arteries.

PURPOSE: To analyze the relationship between late contrast enhancement (LCE) and the interstitial distribution volume (V(In)) of gadolinium (Gd) tracers in the myocardial infarction (MI) areas supplied by chronically occluded arteries from patients. In animal experimental models, LCE has already been shown to correspond to an enhanced V(In) of Gd tracers and thus, to a decrease in the amount of intact cells. MATERIALS AND METHODS: A multicompartmental analysis was applied to serial MRI images encompassing both infarct and remote areas and recorded with a conventional two-dimensional (2D) segmented inversion-recovery gradient-echo (IR-GRE) sequence during a 15-minute period following Gd-diethylenetriamine pentaacetic acid (Gd-DTPA) injection in 12 patients with Q-wave MI supplied by chronically occluded coronary arteries. RESULTS: V(In) from infarct tissue was: 1) higher than V(In) from remote areas (in % of myocardial volume: 74 +/- 16% vs. 20 +/- 7%, P < 0.001); and 2) correlated with the quantification of LCE between infarct and noninfarct areas at the 15th minute (R(2) = 0.63, P = 0.002). However, the difference in V(In) between infarct and remote myocardium was a much better correlate of this quantified LCE (R(2) = 0.85, P < 0.001). CONCLUSION: Detection of LCE in the MI territories supplied by chronically occluded arteries relates to the difference in the V(In) of tracers between the infarct and the noninfarct areas.

Electroanatomic characterization of post-infarct scars comparison with 3-dimensional myocardial scar reconstruction based on magnetic resonance imaging.

OBJECTIVES: This study was designed to compare electroanatomic mapping (EAM) and magnetic resonance imaging (MRI) with delayed contrast enhancement (DCE) data for delineation of post-infarct scars. BACKGROUND: Electroanatomic substrate mapping is an important step in the post-infarct ventricular tachycardia (VT) ablation strategy, but this technique has not yet been compared with a gold-standard noninvasive tool informing on the topography and transmural extent of myocardial scars in humans. METHODS: Ten patients (9 men, age 71 +/- 10 years) admitted for post-infarct VT ablation underwent both a left ventricle DCE MRI and a sinus-rhythm 3-dimensional (3D) (CARTO) EAM (Biosense Webster, Johnson & Johnson, Diamond Bar, California). A 3D color-coded MRI-reconstructed left ventricular endocardial shell was generated to display scar data (intramural location and transmural extent). A matching process allocated any CARTO point to its corresponding position on the MRI map. Electrogram (EGM) characteristics were then evaluated in relation to scar data. RESULTS: A spiky EGM morphology, a reduced unipolar or bipolar EGM voltage amplitude (<6.52 and <1.54 mV, respectively), as well as a longer bipolar EGM duration (>56 ms) independently correlated with the presence of scar whatever its intramural position. Endocardial scars had a larger degree of signal reduction than intramural or epicardial scars. None of the parameters was correlated with transmural scar depth. A clear mismatch in infarct surface between CARTO and MRI maps was observed in one-third of infarct zones. CONCLUSIONS: Sinus-rhythm EAM helps identify the limits of post-infarct scars. However, the accuracy of EAM for precise scar delineation is limited. This limit might be circumvented using anatomical information provided by 3D MRI data.

Detection of myocarditis by contrast-enhanced MRI in patients presenting with acute coronary syndrome but no coronary stenosis.

PURPOSE: To prospectively assess the use of cardiac MRI with delayed contrast enhancement (DCE) for identifying patients with active myocarditis among those presenting with acute coronary syndrome (ACS) but no coronary stenosis. MATERIALS AND METHODS: A total of 27 consecutive patients (age = 45 +/- 17 years; 14 male) presenting with ACS (chest pain, positive troponin-I) and no coronary stenosis, underwent cardiac MRI 9 +/- 7 days after pain onset and 8 +/- 5 months later (N = 19). Steady-state free-precession pulse (SSFP) sequence was applied for the assessment of myocardial function and both inversion-recovery (IR) and SSFP sequences were used for analyzing the topography and extent of DCE areas. Rest sestamibi-gated-single photon emission CT (SPECT) was also systematically performed. RESULTS: Subepicardial DCE pattern typical of acute myocarditis was documented in 12 patients (44%). Ischemic DCE pattern (transmural or subendocardial focal DCE) was documented in 12 of the 15 remaining patients (44%). Patients with subepicardial DCE had: higher C-reactive protein (CRP) levels (38 +/- 32 vs. 14 +/- 24 mg/mL; P = 0.04), lower Framingham cardiovascular risk (3 +/- 3% vs. 9 +/- 5%; P < 0.001), lower incidence of perfusion SPECT defects (17% vs. 73%; P = 0.01), higher left ventricular (LV) end-diastolic volume (77 +/- 16 vs. 64 +/- 10 mL/m(2); P = 0.02), and higher regression of DCE areas at follow-up (-65 +/- 17% vs. -18 +/- 23%; P = 0.002). CONCLUSION: DCE pattern of active myocarditis can be seen in patients presenting with ACS but no coronary stenosis.

Nitrate-enhanced gated SPECT in patients with primary angioplasty for acute myocardial infarction: evidence of a reversible and nitrate-sensitive impairment of myocardial perfusion.

PURPOSE: Reperfusion of myocardial infarction (MI) leads to a reversible dysfunction of coronary vessels. We hypothesised that vasodilating drugs such as nitrates might improve sestamibi uptake within viable areas of recently reperfused MI, thereby enhancing prediction of subsequent improvements in perfusion and contractility. This study was aimed at assessing nitrate-enhanced sestamibi gated SPECT after MI reperfusion. METHODS: Twenty-nine patients underwent rest followed by nitrate sestamibi gated SPECT at 9 +/- 3 days after primary angioplasty for acute MI and at follow-up, 4-10 months later. Four MBq/kg of (99m)Tc-sestamibi was injected at rest, and 12 MBq/kg after nitroglycerin spray. RESULTS: Follow-up improvements were documented for both perfusion (P+) and contractility (C+) in 18% of the 180 initially abnormal segments, in neither perfusion (P-) nor contractility (C-) in 44%, in contractility only (C+P-) in 16% and in perfusion only (C-P+) in 22%. Perfusion improvement was related to lower sestamibi uptake on baseline rest SPECT (P+: 42 +/- 15% vs P-: 50 +/- 15%, p = 0.001) and, moreover, to a higher increase between rest and nitrate uptake (P+: +9.5 +/- 6.5% vs P-: +2.0 +/- 5.9%, p < 0.001). Contractility improvement was related to sestamibi uptake on baseline nitrate SPECT (C+: 58 +/- 15% vs C-: 38 +/- 16%, p < 0.001), a variable enhancing the prediction provided by sestamibi uptake at rest (p < 0.05). CONCLUSION: The improvement in perfusion which is documented in the months following MI reperfusion is predicted by initial nitrate enhancement of sestamibi uptake, suggesting a mechanism of reversible vascular injury. In this particular setting, sestamibi uptake is a better predictor of contractility recovery when determined after nitrate administration rather than under conventional resting conditions.

Gated SPECT assessment of left ventricular function is sensitive to small patient motions and to low rates of triggering errors: a comparison with equilibrium radionuclide angiography.

BACKGROUND: Patient displacements and errors in R-wave detection are the main causes of inaccurate acquisition for gated single photon emission computed tomography (SPECT) and equilibrium radionuclide angiography (RNA). This study aimed to compare the influences of both factors between gated SPECT and RNA determinations of left ventricular ejection fraction. METHODS AND RESULTS: On gated SPECT and RNA acquisitions, recorded in 20 patients with coronary artery disease, we simulated the consequences of (1) 3-dimensional patient displacements of low (6.7 mm), moderate (13.4 mm), and high amplitude (20.1 mm) and (2) an erroneous triggering on T waves in 10% to 40% of recorded beats. Absolute values of left ventricular ejection fraction changes from baseline were higher with gated SPECT compared with RNA for patient displacements of low amplitude (5.0% +/- 3.8% vs 1.2% +/- 0.9%, P < .001) or moderate amplitude (10.0% +/- 6.2% vs 3.0% +/- 2.3%, P = .001) but not for patient displacements of high amplitude (12% +/- 9% vs 9% +/- 7%, P = not significant) and inaccurate triggering (for 20% T-wave triggering, 8.9% +/- 3.6% vs 7.9% +/- 3.0%; P = not significant). CONCLUSION: Contrary to RNA, gated SPECT is vulnerable to small patient displacements, and thus, specific efforts might be useful for limiting this potential cause of erroneous results. Both techniques may be affected by low rates of triggering errors, suggesting that small acceptance windows on cycle length should be recommended not only for RNA but also for gated SPECT.

Residual exercise SPECT ischemia on treatment is a main determinant of outcome in patients with coronary artery disease treated medically at long-term with beta-blockers.

BACKGROUND: Beta-blockers are potent anti-ischemic medications, able to improve prognosis in patients with coronary artery disease (CAD). However, it is not known whether beta-blockers have the same beneficial prognostic effect when residual ischemia persists on treatment. METHODS AND RESULTS: The prognostic impact of exercise single photon emission computed tomography (SPECT) ischemia was analyzed in 442 patients with chronic CAD, who were treated with beta-blockers and who were referred to exercise thallium 201 SPECT, while they were receiving their daily-life medications. Ischemic and viable myocardium was documented on Tl-201 SPECT in 190 patients (43%), of whom only 23% had angina and only 26% had positive exercise testing results. During a follow-up of 3.8 +/- 1.7 years, 36 patients died and survival curves were progressively divergent between patients with and those without ischemic and viable myocardium: at 5 years, the respective survival rates were 81% +/- 4% and 94% +/- 2% (P =.004). By multivariate analysis, the best independent predictors of death were large extent of necrosis (>25% of left ventricle on Tl-201 SPECT, P <.001) and ischemic and viable myocardium (P =.001). CONCLUSIONS: In the CAD patients treated on a long-term basis with beta-blockers, survival is strongly influenced by persistent exercise SPECT ischemia on treatment. Therefore exercise SPECT on treatment could be a useful tool for selecting those who might benefit from additional anti-ischemic therapeutic interventions.