Myocardial Perfusion Imaging In Patients Research Articles

Prospectively accelerated first-pass myocardial perfusion imaging in patients using motion-compensated compressed sensing exploiting regional low-rank sparsity

Background First-pass perfusion CMR utilizes accelerated imaging to achieve high spatial resolution and coverage within a small acquisition window. Several compressed sensing (CS) methods have been proposed to accelerate perfusion imaging. However, patient motion due to imperfect breathholding and other factors leads to degraded quality of CS-reconstructed images. We recently demonstrated a CS method (Block LOw-rank Sparsity with Motion guidance, BLOSM) that exploits regional lowrank sparsity and compensates for the effects of motion, and the dvantages of BLOSM were demonstrated using retrospectively-undersampled first-pass data. In the present study, prospectively-accelerated first-pass data were collected from patients undergoing clinically ordered CMR studies, and we compared image quality for images reconstructed using BLOSM and the k-t SLR method, a reference CS method that exploits global low-rank sparsity.

経皮的冠動脈形成術後の負荷心筋血流イメージング検査

経皮的冠動脈形成術後の負荷心筋血流イメージング検査

High reproducibility of adenosine stress cardiac MR myocardial perfusion imaging in patients with non-ischaemic dilated cardiomyopathy

ObjectiveTo evaluate the reproducibility of first-pass contrast-enhanced cardiac MR (CMR) myocardial perfusion imaging in patients with non-ischaemic dilated cardiomyopathy (NIDCM).DesignProspective observational study.SettingSingle centre, tertiary care hospital.Participants6 outpatient participants with NIDCM.OutcomeReproducibility...

Detection of Radiation-Induced Heart Disease by Gated Myocardial Perfusion Imaging in Patients With Esophageal Cancer During RT: Prevention/Screening

As an important treatment for thoracic cancers, radiation therapy (RT) can cause definite cardiotoxicity, even with modern techniques, such as 3D-CRT and IMRT. This prospective study was initiated to assess radiation-induced heart disease (RIHD) during-RT (at 40 Gy) using gated 99mTc-sestamibi (MIBI) single photon emission computed tomography (SPECT) in patients with esophageal cancer. This ongoing study aimed to investigate the value of 99mTc-MIBI SPECT in the detection of RIHD as early as during-RT.

Detection of Radiation-Induced Heart Disease by Gated Myocardial Perfusion Imaging in Patients With Esophageal Cancer During RT

As an important treatment for thoracic cancers, radiation therapy (RT) can cause definite cardiotoxicity, even with modern techniques, such as 3D-CRT and IMRT. This prospective study was initiated to assess radiation-induced heart disease (RIHD) during-RT (at 40Gy) using gated 99mTc-sestamibi (MIBI) single photon emission computed tomography (SPECT) in patients with esophageal cancer. This ongoing study aimed to investigate the value of 99mTc-MIBI SPECT in the detection of RIHD as early as during-RT.

The prognostic value of left ventricular mechanical dyssynchrony using gated myocardial perfusion imaging in patients with end-stage renal disease

BackgroundPrior studies show that left ventricular mechanical dyssynchrony (LVD), measured by gated SPECT myocardial perfusion imaging (MPI), identifies patients with end-stage renal disease (ESRD) at higher risk for all-cause mortality but these were in small number of patients. We sought to assess the interaction between LVD and LV perfusion pattern in risk-stratification of a large sample size of patients with ESRD. MethodsFrom the renal transplantation database maintained at the University of Alabama at Birmingham, we identified consecutive patients with ESRD who had gated SPECT MPI between 2003 and 2007. MPIs were reprocessed to derive LV ejection fraction (EF), perfusion defect size, and LVD [phase bandwidth (BW) and phase standard deviation (SD)]. The primary end-point was all-cause mortality, which was prospectively collected and verified against the social security death index database. ResultsThere were 828 patients aged 52.6 ± 0.36 years (45% were women and 60% had diabetes mellitus). The LVEF was 54.8 ± 0.4% and the perfusion pattern was abnormal in 334 patients (41%). During a follow-up period of 61 ± 0.9 months, 230 patients (28%) received renal transplants and 290 patients (35%) died. The phase BW (73.1 ± 2.6° vs 66.3 ± 1.8°, P = .02) and SD (25.2 ± 0.8° vs 23.4 ± 0.5°, P = .06) were greater in patients who died than those who survived indicating greater dyssynchrony. Patients with phase BW >56° or SD ≥21° (median values) had worse 5-year survival (64% vs 72%, and 66% vs 71%, log-rank P = .005 and P = .07, respectively). After adjusting for demographics, co-morbidities, LVEF, and perfusion pattern, phase BW was associated with worse outcome (hazard ratio 1.289 95% CI 1.010-1.644, P = .04). ConclusionsLVD by phase analysis of gated SPECT MPI provides prognostic value in ESRD beyond myocardial perfusion and EF.

Radioiodinated acebutolol as a new highly selective radiotracer for myocardial perfusion imaging.

Acebutolol was successfully labeled with (125) I via direct electrophilic substitution reaction. Radioiodinated acebutolol was prepared with a maximum radiochemical yield of 96.5 ± 0.3% and in vitro stability up to 72 h. The in vivo biological distribution of radioiodinated acebutolol showed high heart uptake of 37.8 ± 0.14% injected activity/g organ with low lungs and liver uptakes at 5 min post-injection. In vivo receptor blocking study was carried out in mice to evaluate its selectivity to heart. Radioiodinated acebutolol showed fast heart accumulation with high heart/liver ratio, which provides the ability for fast myocardial imaging with significant decrease in the radiation hazards risk on patients. So, radioiodinated acebutolol could be displayed as a radiotracer drug of choice in case of emergency patients for myocardial perfusion imaging.

Abstract 212: Temporal Trends of SPECT Myocardial Perfusion Imaging in Patients with Coronary Heart Disease: A 22-Year Experience from a Tertiary Academic Medical Center

Background: Over the past 20 years, there has been an increasing decline in the prevalence of abnormal stress single-photon emission computed tomography myocardial perfusion imaging (SPECT) studies among patients with no history of coronary artery disease (CAD). The trend of SPECT studies among patients with known CAD has not been evaluated before. Methods: Using the Mayo Clinic nuclear cardiology database, we examined all stress SPECT tests performed between 1/1991-12/2012 in patients with prior history of CAD defined as having prior myocardial infarction, percutaneous coronary intervention, and/or coronary artery bypass grafting. Patients with left bundle branch block, paced rhythm, bicycle or rest-only tests, cardiomyopathy, valvular heart disease, and technically unsatisfactory studies were excluded. The study cohort was divided into 5 time periods: 1991-5, 1996-2000, 2001-5, 2006-10, and 2011-12. Results: There were 19373 eligible SPECT tests (mean age 66.2 ± 10.9y, 75.4% men). Annual utilization of SPECT studies in patients with history of CAD increased from an average of 495 tests per year between 1991-1995 to a peak of 1425 in 2003; and then decreased to 552 tests in 2012. Asymptomatic patients comprised 33% in 1991-1995, peaked at 48% in 2006, and then decreased back to 31% in 2012. Over time, patients with typical angina decreased while patients with dyspnea increased, P <0.001 (Fig 1). The percentage of high risk SPECT tests significantly decreased, and the percentage of low-risk SPECT tests significantly increased despite the overall decline of SPECT utilization between 2003 and 2012. Almost 80% of all tests performed in 2012 had a low risk summed stress score compared to 29% in 1991, P <0.001 (Fig 2). Conclusions: In Mayo Clinic Rochester, annual SPECT utilization in patients with prior CAD increased between 1992 and 2003, but then decreased significantly after 2003. Fewer patients had typical angina while patients with dyspnea increased over time. High risk SPECT tests declined while low risk tests increased dramatically. These data suggest that stress SPECT was being increasingly utilized in CAD patients without typical angina who are at low risk.

Higher event rate in patients with known CAD despite a normal myocardial perfusion scan.

The negative predictive value of a normal single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) is very high. However, prognostic implication of a normal SPECT MPI in patients with known coronary artery disease (CAD) is not clear. Objective of this study was to evaluate the cardiac event rate in patients with known CAD who had a normal stress SPECT MPI. This prospective study accrued 428 consecutive patients with a history of CAD [revascularization or previous myocardial infarction (MI)] who had a normal stress (dynamic exercise or dipyridamole intervention) and rest Tc-99m-MIBI SPECT MPI. These patients were followed for 2-5 years (median: 3.1 years) for all-cause and cardiac mortality and non-fatal MI. Univariate and multivariate analyses were performed to identify predictors of outcome. During a follow-up period, all-cause mortality was found in 60 patients (14%) and 41 (10%) died of cardiac reasons. Non-fatal MI was found in 77 (18%) patients. Annualized cardiac mortality and non-fatal MI rates were 2% and 3.6% respectively. Smoking, congestive heart failure (CHF) and failure to achieve 85% age predicted heart rate were found to be predictors for all-cause and cardiac mortality. Diabetes, dyslipidemia, smoking and limited functional capacity (<7 METS) were found to be predictors for non-fatal MI. Patients with known CAD had higher cardiac event rates despite a normal stress SPECT MPI. Diabetes, dyslipidemia, smoking and limited functional capacity were the predictors for fatal and non-fatal cardiac events. A cost effective but comprehensive surveillance strategy is warranted.

The influence of coronary calcium score on the interpretation of myocardial perfusion imaging

PurposeCoronary artery calcium (CAC) scores influence the pre-test likelihood of ischemia in patients undergoing myocardial perfusion imaging (MPI). We investigated the influence of CAC score knowledge on the visual interpretation of MPI in patients referred for the diagnostic work-up of suspected coronary artery disease. MethodsWe retrospectively analyzed symptomatic patients who were referred for MPI. For the current analysis, we selected 151 patients who underwent SPECT MPI with simultaneous CAC scoring. MPI was visually interpreted in two separate sessions, first without and then with knowledge of the CAC score. MPI results were classified into four groups: normal, fixed defects, ischemia, and equivocal. ResultsMean age of the patients was 64 ± 11 years, 56 % were male. Without knowledge of the CAC score MPI was evaluated as normal in 36 %, compared to 40 % with knowledge of the CAC score (P = 0.636). Overall, the addition of the CAC score changed the interpretation of MPI in 56 patients (37 %). Importantly, the frequency of equivocal MPI interpretations decreased from 21 % without knowledge of CAC score to 9 % with knowledge of CAC score (P = 0.002). ConclusionsKnowledge of the CAC score has a major impact on the interpretation of MPI, increasing the interpretative certainty.

Circulation : Cardiovascular Imaging

<i>Circulation</i> : <i>Cardiovascular Imaging</i>

The prognostic value of transient ischemic dilatation with otherwise normal SPECT myocardial perfusion imaging: A cautionary note in patients with diabetes and coronary artery disease

BackgroundThe prognostic implications of transient ischemic dilatation (TID) of the left ventricle with otherwise normal single-photon emission computed tomography myocardial perfusion imaging (MPI) remain controversial. Whether this finding may have prognostic implications only in high-risk populations, such as patients with diabetes or manifest coronary artery disease (CAD), is uncertain. MethodsWe conducted a prospective cohort study of 1,236 consecutive patients with normal 99mTc-sestamibi MPI, defined as normal perfusion (summed stress score = 0) and normal left ventricle volume and function. TID was defined as >2 standard deviations above the mean of patients with low likelihood of CAD. ResultsThe study subjects were followed for 27 ± 9 months. The 76 (6%) patients with TID had a greater rate of cardiac death or myocardial infarction (MI) [4 (5.3%) vs 11 (0.6%), P = .003] independent of covariates [hazard ratio = 6.4, P = .004]. This finding was entirely derived from the subgroup of 294 patients with diabetes or CAD [4 (13.3%) with TID vs 1 (0.4%) without TID, P = .001] independent of covariates. However, TID was not predictive of cardiac death or MI among the 941 patients without diabetes or CAD. Furthermore, TID was not predictive of coronary revascularization. ConclusionsThis study confirms a benign prognosis of TID with otherwise normal MPI in patients without diabetes or CAD, but cautions against extending this conclusion to high-risk individuals, particularly those with diabetes or CAD.

Evaluation of ASPIRE trial: a Phase III pivotal registration trial, using intracoronary administration of Generx (Ad5FGF4) to treat patients with recurrent angina pectoris

The ASPIRE study (a randomized, controlled, parallel group, multicenter study to evaluate the efficacy and safety of Ad5FGF-4 using adenosine single-photon emission computed tomography (SPECT) myocardial perfusion imaging in patients with stable angina pectoris) (ClinicalTrials.gov Identifier: NCT01550614) is a 100-patient, controlled, randomized, multicenter study conducted in six centers in Russia. This trial will assess the therapeutic efficacy of Generx (Ad5-FGF4) using rest and stress SPECT following a one-time, catheter-based administration. Adenovirus-based antianginal therapy represents an interesting option but the difficulties observed in the various trials carried out to date illustrate the complexity of the issue. Large and well-designed studies should be encouraged to provide definitive answers to this important research question.

Gated-SPECT Myocardial Perfusion Imaging as a Complementary Technique to Magnetic Resonance Imaging in Chronic Myocardial Infarction Patients

Introduction and objectivesThe aim of this study was to compare magnetic resonance and gated-SPECT myocardial perfusion imaging in patients with chronic myocardial infarction. MethodsMagnetic resonance imaging and gated-SPECT were performed in 104 patients (mean age, 61 [12] years; 87.5% male) with a previous infarction. Left ventricular volumes and ejection fraction and classic late gadolinium enhancement viability criteria (<75% transmurality) were correlated with those of gated-SPECT (uptake >50%) in the 17 segments of the left ventricle. Motion, thickening, and ischemia on SPECT were analyzed in segments showing nonviable tissue or equivocal enhancement features (50%-75% transmurality). ResultsA good correlation was observed between the 2 techniques for volumes, ejection fraction (P<.05), and estimated necrotic mass (P<.01). In total, 82 of 264 segments (31%) with >75% enhancement had >50% single SPECT uptake. Of the 106 equivocal segments on magnetic resonance imaging, 68 (64%) had >50% uptake, 41 (38.7%) had normal motion, 46 (43.4%) had normal thickening, and 17 (16%) had ischemic criteria on SPECT. ConclusionsA third of nonviable segments on magnetic resonance imaging showed >50% uptake on SPECT. Gated-SPECT can be useful in the analysis of motion, thickening, and ischemic criteria in segments with questionable viability on magnetic resonance imaging.

Gated-SPECT de perfusión miocárdica como técnica complementaria de la resonancia magnética para pacientes con infarto de miocardio crónico

Introduction and objectivesThe aim of this study was to compare magnetic resonance and gated-SPECT myocardial perfusion imaging in patients with chronic myocardial infarction. MethodsMagnetic resonance imaging and gated-SPECT were performed in 104 patients (mean age, 61 [12] years; 87.5% male) with a previous infarction. Left ventricular volumes and ejection fraction and classic late gadolinium enhancement viability criteria (<75% transmurality) were correlated with those of SPECT (uptake >50%) in the 17 segments of the left ventricle. Motion, thickening, and ischemia on gated-SPECT were analyzed in segments showing nonviable tissue or equivocal enhancement features (50%-75% transmurality). ResultsA good correlation was observed between the 2 techniques for volumes, ejection fraction (P<.05), and estimated necrotic mass (P<.01). In total, 82 of 264 segments (31%) with >75% enhancement had >50% SPECT uptake. Of the 106 equivocal segments (50%-75% enhancement) on magnetic resonance imaging, 68 (64%) had >50% uptake, 41 (38.7%) had normal motion, 46 (43.4%) had normal thickening, and 17 (16%) had ischemic criteria on SPECT. ConclusionsA third of nonviable segments on magnetic resonance imaging showed >50% uptake on SPECT. Gated-SPECT can be useful in the analysis of motion, thickening, and ischemic criteria in segments with questionable viability on magnetic resonance imaging.Full English text available from:www.revespcardiol.org/en

Abstract 40: Temporal Trends of SPECT Myocardial Perfusion Imaging in Patients without Coronary Artery Disease: A 17-Year Experience from a Tertiary Academic Medical Center

Background: Between 1990-2006, there was a tremendous increase in utilization of single photon emission computed tomography myocardial perfusion imaging (SPECT). Characteristics of the observed increase of SPECT utilization have never been studied. Methods: Using the Mayo Clinic nuclear cardiology database, we examined all SPECT tests performed between 1/1/1991-12/31/2007 in patients without prior coronary artery disease (CAD). Patients with history of CAD, left bundle branch block, paced rhythm, bicycle/ rest-only tests, cardiomyopathy, valvular heart disease, and technically unsatisfactory studies were excluded. The study cohort was divided into 4 time periods: 1991-5, 1996-2000, 2001-5, and 2006-7. Results: There were 29255 eligible SPECT tests (mean age 62.4 ± 12y, 54% men). Annual utilization of SPECT studies increased from 682 in 1992 to a peak of 2738 in 2002, and then decreased to 2134 in 2007, Fig 1. There were very modest changes in CAD risk factors over time. Testing of asymptomatic patients nearly doubled (21.9% in 1991-5 to 42.7% in 2006-7). Tests on patients with typical angina decreased dramatically (18.3% in 1991-5 to 5.3% in 2006-7), Fig 2. Summed stress score, summed difference score, and high risk SPECT tests decreased over time, Fig 3. Normal SPECT studies and negative study ECG increased for both pharmacologic and exercise tests. Conclusions: In Mayo Clinic Rochester, annual SPECT utilization in patients without prior CAD increased between 1992 and 2002, but then decreased in advance of national trends. Normal tests increased, while summed stress score, summed difference score, and high risk tests all decreased. These data suggest that SPECT was increasingly utilized in patients with a lower prevalence of CAD.

Incremental prognostic value of myocardial perfusion imaging in patients with renal dysfunction

Coronary artery disease is the main cause of mortality and morbidity in patients with impaired renal function. The aim of this study is to evaluate the prognostic implications of single-photon emission computed tomography myocardial perfusion imaging (SPECT-MPI) in patients with impaired renal function. We included 11,829 consecutive patients (mean age, 65 ± 12 years; 52% men) referred for SPECT-MPI between April 2004 and May 2009. Renal function was estimated using the estimated glomerular filtration rate (GFR) formula. Patients were followed up for a composite endpoint of all-cause mortality and nonfatal myocardial infarction (D/MI). Multiple nested Cox proportional hazard models were used to determine the incremental prognostic value of SPECT-MPI over clinical features and renal function. A total of 916 (8%) and 3565 (31%) patients had GFR less 30 and between 30 and 60 mL/min/1.73 m2 respectively. Patients with decreased GFR were more often older, with higher prevalence of conventional risk factors (P < 0.001). After a median follow-up of 5 years (25th to 75th percentiles, 3–6.5 years), 2578 (22%) patients experienced D/MI (764 MI and 2113 dead). The risk of death increased with worsening kidney function. At each stage of impaired renal function, patients with abnormal SPECT-MPI had increased hazard of adverse events (P < 0.0001). Using Cox regression, total perfusion defect offered improved discriminatory ability beyond traditional risk factors (area under the receiver operator curve [AUC] 0.742 vs. 0.759, p < 0.0001). SPECT-MPI adds incremental prognostic information to identify patients at higher relative risk of D/MI across a wide spectrum of renal function.

Yield and Diagnostic Value of Stress Myocardial Perfusion Imaging in Patients Without Known Coronary Artery Disease Presenting With Syncope

American College of Cardiology/American Heart Association appropriate use criteria recommend performing stress myocardial perfusion imaging (MPI) for intermediate- to high-risk patients presenting with syncope but not for low-risk patients. However, there are limited data to support these recommendations. We investigated the yield of stress MPI for the evaluation of syncope in patients at risk but without known coronary artery disease. Using the Cleveland Clinic Institutional Review Board-approved MPI database, we identified consecutive patients without known coronary artery disease who underwent stress MPI between 2006 and 2012 for diagnostic workup of syncope. Patients were stratified into low-, intermediate-, and high-risk groups using the Framingham risk score. For patients with abnormal MPI, left heart catheterization were reviewed if performed. There were 700 patients (mean age, 62±15 years; 55% female) who had undergone stress MPI for syncope; 659 patients (94%) had normal perfusion. Of the 41 patients with abnormal MPI, 18 had left heart catheterization (9 were false-positive); there were 23 remaining patients with abnormal MPI (16 having moderate to severe perfusion defect size) but who did not have a left-side angiogram and could have undiagnosed significant coronary artery disease. The diagnostic yield of stress MPI was similarly low among all cardiovascular risk categories. Stress MPI for evaluation of syncope in patients without known coronary artery disease has a low-diagnostic yield among all risk categories; thus, reaffirmation and revision of the appropriateness criteria should be considered.

False-positive defects on exercise 99mTc-sestamibi SPECT imaging, but not on dipyridamole 99mTc-sestamibi SPECT imaging, in a patient with right bundle branch block (RBBB)

False-positive findings with myocardial perfusion imaging (MPI) have frequently been identified in the presence of left bundle branch block (LBBB) and tend to lower the accuracy of MPI in individuals with normal coronary angiographs. Pharmacologic stress is recognized as the preferred method for MPI in patients with LBBB. In contrast, very few studies have evaluated the effect of right bundle branch block (RBBB) on MPI, and there is no consensus regarding the selection of pharmacologic versus exercise stress during MPI for the RBBB patient. In this study, we present a 45-year-old man with RBBB, who has a normal coronary artery angiography, but who showed abnormal myocardial perfusion with exercise MPI, and normal perfusion on dipyridamole MPI. The aim of the study is to stimulate awareness that the stress method selected for patients with RBBB can potentially interfere with the accuracy of the data.

Myocardial perfusion imaging in patients with a recent, normal exercise test

To investigate the added value of myocardial perfusion scintigraphy imaging (MPI) in consecutive patients with suspected coronary artery disease (CAD) and a recent, normal exercise electrocardiography (ECG). This study was a retrospective analysis of consecutive patients referred for MPI during a 2-year period from 2006-2007 at one clinic. All eligible patients were suspected of suffering from CAD, and had performed a satisfactory bicycle exercise test (i.e., peak heart rate > 85% of the expected, age-predicted maximum) within 6 mo of referral, their exercise ECG was had no signs of ischemia, there was no exercise-limiting angina, and no cardiac events occurred between the exercise test and referral. The patients subsequently underwent a standard 2-d, stress-rest exercise MPI. Ischemia was defined based on visual scoring supported by quantitative segmental analysis (i.e., sum of stress score > 3). The results of cardiac catheterization were analyzed, and clinical follow up was performed by review of electronic medical files. A total of 56 patients fulfilled the eligibility criteria. Most patients had a low or intermediate ATPIII pre-test risk of CAD (6 patients had a high pre-test risk). The referral exercise test showed a mean Duke score of 5 (range: 2 to 11), which translated to a low post-exercise risk in 66% and intermediate risk in 34%. A total of seven patients were reported with ischemia by MPI. Three of these patients had high ATPIII pre-test risk scores. Six of these seven patients underwent cardiac catheterization, which showed significant stenosis in one patient with a high pre-test risk of CAD, and indeterminate lesions in three patients (two of whom had high pre-test risk scores). With MPI as a gate keeper for catheterization, no significant, epicardial stenosis was observed in any of the 50 patients (0%, 95% confidence interval 0.0 to 7.1) with low to intermediate pre-test risk of CAD and a negative exercise test. No cardiac events occurred in any patients within a median follow up period of > 1200 d. The added diagnostic value of MPI in patients with low or intermediate risk of CAD and a recent, normal exercise test is marginal.