Comparing the Prognostic Value of Stress Myocardial Perfusion Imaging by Conventional and Cadmium-Zinc Telluride Single-Photon Emission Computed Tomography through a Machine Learning Approach.

We compared the prognostic value of myocardial perfusion imaging (MPI) by conventional- (C-) single-photon emission computed tomography (SPECT) and cadmium-zinc-telluride- (CZT-) SPECT in a cohort of patients with suspected or known coronary artery disease (CAD) using machine learning (ML) algorithms. A total of 453 consecutive patients underwent stress MPI by both C-SPECT and CZT-SPECT. The outcome was a composite end point of all-cause death, cardiac death, nonfatal myocardial infarction, or coronary revascularization procedures whichever occurred first. ML analysis performed through the implementation of random forest (RF) and k-nearest neighbors (KNN) algorithms proved that CZT-SPECT has greater accuracy than C-SPECT in detecting CAD. For both algorithms, the sensitivity of CZT-SPECT (96% for RF and 60% for KNN) was greater than that of C-SPECT (88% for RF and 53% for KNN). A preliminary univariate analysis was performed through Mann-Whitney tests separately on the features of each camera in order to understand which ones could distinguish patients who will experience an adverse event from those who will not. Then, a machine learning analysis was performed by using Matlab (v. 2019b). Tree, KNN, support vector machine (SVM), Naïve Bayes, and RF were implemented twice: first, the analysis was performed on the as-is dataset; then, since the dataset was imbalanced (patients experiencing an adverse event were lower than the others), the analysis was performed again after balancing the classes through the Synthetic Minority Oversampling Technique. According to KNN and SVM with and without balancing the classes, the accuracy (p value = 0.02 and p value = 0.01) and recall (p value = 0.001 and p value = 0.03) of the CZT-SPECT were greater than those obtained by C-SPECT in a statistically significant way. ML approach showed that although the prognostic value of stress MPI by C-SPECT and CZT-SPECT is comparable, CZT-SPECT seems to have higher accuracy and recall.

The additive prognostic value of coronary calcium score (CCS) to single photon emission computed tomography myocardial perfusion imaging (SPECT-MPI)-real world data from a single center.

AIMS: Single-photon emission computed tomography myocardial perfusion imaging [SPECT-MPI] is a functional test for coronary ischemia. We aimed to assess the additive prognostic value of coronary calcium score (CCS) to SPECT-MPI in stable patients. METHODS: This study is a retrospective analysis of 655 patients who underwent SPECT-MPI with CCS (2012 to 2017). Receiver operator characteristic (ROC) identified CCS cutoff value for all-cause mortality: CCS+ if > cutoff value and MPI+ if ≥ 5% total perfusion defect (TPD). Patients were divided into 1 MPI-/CCS-; 2 MPI+/CCS-; 3 MPI-/CCS+; 4 MPI+/CCS+ and compared. Cox proportional hazard analysis identified predictors of mortality. RESULTS: CCS cutoff for all-cause mortality was > 216 (C statistic 0.756, P < 0.0001). In MPI+ groups, mean TPD was similar (13.4% and 13.1% respectively) but mortality was higher in the CCS+ (12.5% vs. 4.8%, P = 0.22) as was the severe LV systolic dysfunction (8.0% vs. 0%, P = 0.095). In MPI- groups, mean TPD was similar (0.7% and 0.9% respectively) but all-cause mortality was higher in the CCS+ (10.7% vs. 1.6%, P < 0.0001) as was severe LVSD (2.9 % vs. 0.3% P = 0.016). Age, smoking, renal impairment ,and CCS > 216 were independent predictors of mortality. CONCLUSIONS: Patients with raised CCS on SPECT-MPI have increased mortality and poor LV function despite a negative MPI.

Diagnostic accuracy of stress myocardial computed tomography perfusion imaging to detect myocardial ischemia: a comparison with coronary flow velocity reserve derived from transthoracic Doppler echocardiography.

BACKGROUND: Our aim was to evaluate the ability of adenosine triphosphate (ATP)-stress myocardial computed tomography perfusion (CTP) imaging to detect myocardial ischemia in the left anterior descending artery (LAD) territory, and to compare this method with coronary flow velocity reserve (CFVR) measured by transthoracic Doppler echocardiography (TTDE). METHODS: ATP-stress CTP and CFVR were performed in 50 patients with stable angina pectoris. Myocardial ischemia assessed from CTP imaging was defined as qualitative visual perfusion defects and reduced myocardial blood flow (MBF) based on quantitative assessment. A cut-off value of CFVR of 2.0 was used. RESULTS: The mean CFVR was 1.9 ± 0.6 in ischemic regions by CTP, whereas it was 2.9 ± 0.8 in non-ischemic regions (p < 0.001). CTP imaging could accurately predict CFVR <2.0 with 84.0% diagnostic accuracy (94.7% sensitivity, 77.4% specificity, 72.0% positive predictive value, and 96.0% negative predictive value). When receiver operating characteristic curve analysis of the MBF data was performed to detect CFVR <2.0, the area under the curve was 0.89, and the optimal MBF cut-off value was 1.43 mL/g/min. CONCLUSIONS: This study suggests that qualitative and quantitative assessment of ATP-stress CTP exhibits a good correlation with CFVR for evaluation of myocardial ischemia.

Comparison of MOLLI and ShMOLLI in Terms of T1 Reactivity and the Relationship between T1 Reactivity and Conventional Signs of Response during Adenosine Stress Perfusion CMR

Background: One of the most important techniques of cardiac magnetic resonance in assessment of coronary heart diseases is adenosine stress myocardial first-pass perfusion imaging. Using this imaging method, there should be an adequate response to the drug adenosine to make an accurate evaluation. The conventional signs of drug response are not always observed and are often subjective. Methods based on splenic perfusion might possess limitations as well. Therefore, T1 mapping presents as a novel, quantitative and reliable method. There are several studies analyzing this newly discovered property of different T1 mapping sequences. However most of these studies are enrolling only one of the techniques. Aims: To compare modified look-locker inversion recovery and shortened modified look-locker inversion recovery sequences in terms of T1 reactivity and to determine the relationship between T1 reactivity and conventional stress adequacy assessment methods in adenosine stress perfusion cardiac magnetic resonance. Study Design: A cross-sectional study using STARD reporting guideline. Methods: Thirty-four consecutive patients, who were referred for adenosine stress perfusion cardiac magnetic resonance with suspect of myocardial ischemia, were prospectively enrolled into the study. Four patients were disqualified, and thirty patients were included in the final analysis. Using both modified look-locker inversion recovery and shortened modified look-locker inversion recovery, midventricular short axis slices of T1 maps were acquired at rest and during peak adenosine stress before gadolinium administration. Then, they were divided into six segments according to the 17-segment model proposed by the American Heart Association, and separate measurements were made from each segment. Mean rest and mean stress T1 values of remote, ischemic, and infarcted myocardium were calculated individually per subject. During adenosine administration, patients' heart rates and blood pressures are measured and recorded every one minute. Adenosine stress perfusion images were examined for the presence of splenic switch-off. Results: There was a significant difference between rest and stress T1 values of remote myocardium in both modified look-locker inversion recovery and shortened modified look-locker inversion recovery (p<0.001). In both modified look-locker inversion recovery and shortened modified look-locker inversion recovery there was no significant correlation between T1 reactivity and heart rates response (modified look-locker inversion recovery p=0.30, shortened modified look-locker inversion recovery p=0.10), blood pressures response (modified look-locker inversion recovery p=0.062, shortened modified look-locker inversion recovery p=0.078), splenic perfusion (modified look-locker inversion recovery p=0.35, shortened modified look-locker inversion recovery p=0.053). There was no statistically significant difference between modified look-locker inversion recovery and shortened modified look-locker inversion recovery regarding T1 reactivity of remote (p=0.330), ischemic (p=0.068), and infarcted (p=0.116) myocardium. Conclusion: T1 reactivity is independent of the other stress response signs and modified look-locker inversion recovery and shortened modified look-locker inversion recovery do not differ in terms of T1 reactivity.

Myocardial Perfusion SPECT 2018 in Germany: Results of the 8th Survey.

AIM: This paper presents the results of the 8th survey of myocardial perfusion SPECT (MPS) from the reporting year 2018. METHODS: 291 questionnaires (184 practices (PR), 77 hospitals (HO), 30 university hospitals (UH)) were evaluated. Results of the last survey from 2015 are set in squared brackets. RESULTS: MPS of 145 930 [121 939] patients were reported (+ 19.6 %). 76 % [78 %] of all patients were studied in PR, 16 % [14 %] in HO, and 8 % [8 %] in UH, mostly with a 2-day-protocol 48 % [50 %]. 99.96 % [98 %] of all MPS were performed with Tc-99 m radiopharmaceuticals and in 0.04 % with Tl-201.A pharmacological stress test was applied in 49 % [43 %] (23 % [22 %] adenosine, 26 % [20 %] regadenoson, dipyridamole or dobutamine together < 1 % [1 %]). Attenuation correction was performed in 26 % [25 %] of all MPS, gated SPECT in 86 % [80 %] of stress MPS, in 87 % [78 %] of rest and in 83 % [76 %] of all stress and rest MPS. 67 % [53 %] of the departments performed MPS scoring by default, whereas 16 % [24 %] did not apply this feature at all.69 % [60 %] reported an increase or no changes in their MPS patient numbers. One hundred twenty-six departments which participated in the surveys from 2009 to 2018 reported an increase in MPS by 44 %. 69 % [70 %] of the MPS were requested by ambulatory care cardiologists. CONCLUSION: The 2018 MPS survey reveals a high-grade adherence of routine MPS practice to current guidelines. The positive development in MPS performance and MPS numbers observed since 2012 remains ongoing.

Temporal Trends of Single-Photon Emission Computed Tomography Myocardial Perfusion Imaging in Patients With Coronary Artery Disease: A 22-Year Experience From a Tertiary Academic Medical Center.

BACKGROUND: There has been a gradual decline in the prevalence of abnormal stress single-photon emission computed tomography (SPECT) myocardial perfusion imaging studies among patients without history of coronary artery disease (CAD). The trends of SPECT studies among patients with known CAD have not been evaluated previously. METHODS AND RESULTS: We assessed the Mayo Clinic nuclear cardiology database for all stress SPECT tests performed between January 1991 and December 2012 in patients with history of CAD defined as having previous myocardial infarction, percutaneous coronary intervention, and coronary artery bypass grafting. The study cohort was divided into 5 time periods: 1991 to 1995, 1996 to 2000, 2001 to 2005, 2006 to 2010, and 2011 to 2012. There were 19 373 patients with a history of CAD who underwent SPECT between 1991 and 2012 (mean age, 66.2±10.9 years; 75.4% men). Annual utilization of SPECT in these patients increased from an average of 495 tests per year in 1991 to 1995 to 1425 in 2003 and then decreased to 552 tests in 2012 without evidence for substitution with other stress modalities. Asymptomatic patients initially increased until 2006 and then decreased. Patients with typical angina decreased, whereas patients with dyspnea and atypical angina increased. High-risk SPECT tests significantly decreased, and the percentage of low-risk SPECT tests increased despite decreased SPECT utilization between 2003 and 2012. Almost 80% of all tests performed in 2012 had a low-risk summed stress score compared with 29% in 1991 (P<0.001). CONCLUSIONS: In Mayo Clinic, Rochester, annual SPECT utilization in patients with previous CAD increased between 1992 and 2003, but then decreased after 2003. High-risk SPECT tests declined, whereas low-risk tests increased markedly. Our results suggest that among patients with a history of CAD, SPECT was being increasingly utilized in patients with milder CAD. This trend parallels reduced utilization of other stress modalities, coronary angiography, reduced smoking, and greater utilization of optimal medical therapy for prevention and treatment of CAD.

Impact of the Publication of Appropriate Use Criteria on Utilization Rates of Myocardial Perfusion Imaging Studies in Ontario, Canada: A Population-Based Study.

BACKGROUND: Concern regarding overutilization of cardiac imaging has led to the development of appropriate use criteria (AUC). Myocardial perfusion imaging (MPI) is one of the most commonly used cardiac imaging modalities worldwide. Despite multiple iterations of AUC, there is currently no evidence regarding their real-world impact on population-based utilization rates of MPI. Our goal was to assess the impact of the AUC on rates of MPI in Ontario, Canada. We hypothesized that publication of the AUC would be associated with a significant reduction in MPI rates. METHODS AND RESULTS: We conducted a retrospective cohort study of the adult population of Ontario from January 1, 2000, to December 31, 2015. Age- and sex-standardized rates were compared from 4 different periods intersected by 3 published iterations of the AUC. Overall, 3 072 611 MPI scans were performed in Ontario during our study period. The mean monthly rate increased from 14.1/10 000 in the period from January 2000 to October 2005 to 18.2/10 000 between November 2005 and June 2009. After this point in time, there was a reduction in rates, falling to a mean monthly rate of 17.1/10 000 between March 2014 and December 2015. Time series analysis revealed that publication of the 2009 AUC was associated with a significant reduction in MPI rates (P<0.001). This translated into ≈88 849 fewer MPI scans at a cost savings of ≈72 million Canadian dollars. CONCLUSIONS: Our results reflect a potential real-world impact of the 2009 MPI AUC by demonstrating evidence of a significant effect on population-based rates of MPI.

Prevalence of risk factors and asymptomatic carotid atherosclerosis in diabetic patients screened for silent myocardial ischemia by SPECT myocardial imaging.

BACKGROUND: The aim of the study was to evaluate whether there is any association between myocardial ischemia, common risk factors and carotid artery ultrasound parameters in asymptomatic type 2 diabetic (DMT2) patients. MATERIAL AND METHODS: 60 asymptomatic DMT2 patients (pts) without known coronary artery disease (CAD) underwent one day rest Dypiridamole stress Tc-99m sestamibi single photon emission computed tomography myocardial perfusion scintigraphy (MPS). We used 17 segment models for perfusion analysis with the assessment of perfusion scores. Patients were studied for age, sex, hypertension, hyperlipidemia, hs-CRP, smoking, obesity and family history of cardiac disease. Color Ultrasound examination of carotid arteries was performed in all patients. RESULTS: 51 patients (pts) had hypertension, 48 pts had hyperlipidemia, 15 were smokers, 6 pts had BMI > 30 kg/m2 and 26 patients had positive family history for CAD. 18 (31%) patients had myocardial ischemia. Mild ischemia was found in 6 pts, moderate in 7 patients and severe ischemia in 5 patients. Carotid IMT was increased in 34 pts and 15 pts had carotid plaques. Mean c-IMT value in patients with normal MPS results was 0.7 ± 0.1; in moderate ischemia 0.9 ± 0.1 and in pts severe ischemia 1.0 ± 0.2. Multivariate analysis showed obesity, low HDL and increased diastolic blood pressure predictors of increased c-IMT. Increased pulse pressure (PP), age and non-HDL cholesterol were predictors for presence of carotid plaques. Multivariable analysis for prediction of stress induced ischemia showed OR 2.9 (95% CI 2.1-5.1) for male gender, OR 3.1 for systolic blood pressure (95% CI 1.9-3.8) and OR 2.8 for LDL cholesterol (95% CI 1.7-3.6). CONCLUSIONS: Our study has shown high prevalence of traditional risk factors and silent myocardial ischemia in type 2 diabetic patients, with the importance of SPECT imaging in selected diabetes type 2 patients. The study highlights the importance of screening for carotid atherosclerosis, which may be useful to identify diabetic patients at higher risk for coronary artery disease..

Adenosine triphosphate stress myocardial perfusion imaging for risk stratification of patients aged 70 years and older with suspected coronary artery disease.

OBJECTIVE: We investigated the cardiac risk stratification value of adenosine triphosphate stress myocardial perfusion imaging (ATP-MPI) in patients aged 70 years and older with suspected coronary artery disease (CAD). METHODS: We identified a series of 415 consecutive patients aged 70 years and older with suspected CAD, who had undergone ATP-MPI with 99mTc-MIBI. The presence of a fixed and/or reversible perfusion defect was considered as an abnormal MPI. Follow-up was available in 399 patients (96.1%) over 3.45 ± 1.71 years after excluding 16 patients who underwent early coronary revascularization <60 days after MPI. The major adverse cardiac events (MACE), including cardiac death, nonfatal infarction, and late coronary revascularization, were recorded. RESULTS: One hundred twenty-five (31.3%) patients had abnormal MPI and the remaining had normal MPI. A multivariable analysis using Cox regression demonstrated that abnormal MPI was independently associated with MACE (hazard ratio 19.50 and 95% confidence interval 5.91-64.31, P value .000). The patients with SSS > 8 had significantly higher cumulative MACE rate than patients with SSS ≤ 8 had (37.8% vs 5.2%, respectively, P < .001). The Kaplan-Meier cumulative MACE-free survival in patients with abnormal MPI (57.0%) was significantly lower than that in patients with normal MPI (89.6%), P < .0001. Among patients with SSS > 8, the Kaplan-Meier cumulative MACE-free survival were 36.9% in patients ≥80 years old and 49.5% in patients 70-79 years old, respectively, P < .05. However, among patients with SSS ≤ 8, there was no difference between the Kaplan-Meier cumulative MACE-free survivals of these two age groups. CONCLUSIONS: ATP-MPI data are useful for the prediction of major adverse cardiac events in patients aged 70 years and older with suspected CAD.

Opportunities for improvement on current nuclear cardiology practices and radiation exposure in Latin America: Findings from the 65-country IAEA Nuclear Cardiology Protocols cross-sectional Study (INCAPS).

BACKGROUND: Comparison of Latin American (LA) nuclear cardiology (NC) practice with that in the rest of the world (RoW) will identify areas for improvement and lead to educational activities to reduce radiation exposure from NC. METHODS AND RESULTS: INCAPS collected data on all SPECT and PET procedures performed during a single week in March-April 2013 in 36 laboratories in 10 LA countries (n = 1139), and 272 laboratories in 55 countries in RoW (n = 6772). Eight "best practices" were identified a priori and a radiation-related Quality Index (QI) was devised indicating the number used. Mean radiation effective dose (ED) in LA was higher than in RoW (11.8 vs 9.1 mSv, p < 0.001). Within a populous country like Brazil, a wide variation in laboratory mean ED was found, ranging from 8.4 to 17.8 mSv. Only 11% of LA laboratories achieved median ED <9 mSv, compared to 32% in RoW (p < 0.001). QIs ranged from 2 in a laboratory in Mexico to 7 in a laboratory in Cuba. Three major opportunities to reduce ED for LA patients were identified: (1) more laboratories could implement stress-only imaging, (2) camera-based methods of ED reduction, including prone imaging, could be more frequently used, and (3) injected activity of 99mTc could be adjusted reflecting patient weight/habitus. CONCLUSIONS: On average, radiation dose from NC is higher in LA compared to RoW, with median laboratory ED <9 mSv achieved only one third as frequently as in RoW. Opportunities to reduce radiation exposure in LA have been identified and guideline-based recommendations made to optimize protocols and adhere to the "as low as reasonably achievable" (ALARA) principle.

Safety of vasodilator stress myocardial perfusion imaging in patients with elevated cardiac biomarkers.

BACKGROUND: While adenosine and dipyridamole as myocardial perfusion imaging (MPI) stress agents have literature supporting their safety in the setting of myocardial infarction (MI), regadenoson does not. Studying a high risk cohort of patients with elevated cardiac biomarkers may shed light on potential safety issues of these agents which might also affect lower risk cohorts. METHODS: All patients who had undergone a clinically indicated stress MPI study at two academic centers from 1/1/2010 through 12/31/2012 with elevated troponin ≤7 days prior to testing were included. The primary endpoint was a composite of death, non-fatal MI, congestive heart failure (CHF), stroke, ventricular arrhythmias, atrial fibrillation/flutter, or atrioventricular block requiring intervention within 24 h of testing. RESULTS: Of the 703 stress MPI studies that met inclusion criteria, 360 (51.2%), 199 (28.3%), 74 (10.5%), 9 (1.3%), and 61 (8.7%) underwent regadenoson, dipyridamole, adenosine, dobutamine, and exercise stress, respectively. The primary endpoint occurred in 11 (1.6%) patients with an incidence of 1.4% (n = 5), 1.0% (n = 2), 1.4% (n = 1), 11.1% (n = 1), and 3.3% (n = 2) following regadenoson, dipyridamole, adenosine, dobutamine, and exercise stress, respectively (P = 0.137). The adverse events included non-fatal MI in 7 (1.0%) patients, death in 1 (0.1%) patient, CHF in 1 (0.1%) patient, ventricular arrhythmia in 1 (0.1%) patient, and atrial arrhythmia in 1 (0.1%) patient. CONCLUSION: In the setting of elevated troponin, serious complications associated with either exercise or vasodilator stress testing appear to be relatively rare with no increased risk attributable to a particular vasodilator agent.

Aminophylline and caffeine for reversal of adverse symptoms associated with regadenoson SPECT MPI.

BACKGROUND: Aminophylline shortages led us to compare intravenous (IV) aminophylline with IV and oral (PO) caffeine during routine pharmacologic stress testing with SPECT MPI. METHODS: We measured presence, duration, and reversal of adverse symptoms and cardiac events following regadenoson administration in consecutive patients randomized to IV aminophylline (100 mg administered over 30-60 seconds), IV caffeine citrate (60 mg infused over 3-5 minutes), or PO caffeine as coffee or diet cola. RESULTS: Of 241 patients, 152 (63%) received regadenoson reversal intervention. Complete (CR), predominant (PRE), or partial (PR) reversal was observed in 99%. CR by IV aminophylline (87%), IV caffeine (87%), and PO caffeine (78%) were similar (P = NS). Time to CR (162 ± 12.6 seconds, mean ± SD) was similar in treatment arms. PO caffeine was inferior to IV aminophylline for CR + PRE. CONCLUSIONS: IV aminophylline and IV caffeine provide rapid, safe reversal of regadenoson-induced adverse effects during SPECT MPI. Oral caffeine appeared similarly effective for CR but not for the combined CR + PRE. Our results suggest PO caffeine may be an effective initial strategy for reversal of regadenoson, but IV aminophylline or IV caffeine should be available to optimize symptom reversal as needed.

Myocardial perfusion SPECT 2015 in Germany. Results of the 7th survey.

AIM: The working group Cardiovascular Nuclear Medicine of the German Society of Nuclear Medicine presents the results of the 7th survey of myocardial perfusion SPECT (MPS) of the reporting year 2015. METHOD: 268 questionnaires (173 practices [PR], 67 hospitals [HO], 28 university hospitals [UH]) were evaluated. Results of the last survey from 2012 are set in squared brackets. RESULTS: MPS of 121 939 [105 941] patients were reported. 98 % [95 %] of all MPS were performed with Tc-99m radiopharmaceuticals and 2 % [5 %] with Tl-201. 78 % [79 %] of all patients were studied in PR, 14 % [15 %] in HO, and 8 % [6 %] in UH. A pharmacological stress test was performed in 43 % [39 %] (22 % [24 %] adenosine, 20 % [9 %] regadenoson, 1 % [6 %] dipyridamole or dobutamine). Attenuation correction was applied in 25 % [2009: 10 %] of MPS. Gated SPECT was performed in 78 % [70 %] of all rest MPS, in 80 % [73 %] of all stress and in 76 % [67 %] of all stress and rest MPS. 53 % [33 %] of all nuclear medicine departments performed MPS scoring by default, whereas 24 % [41 %] did not apply any quantification. 31 % [26 %] of all departments noticed an increase in their counted MPS and 29 % [29 %] no changes. Data from 89 departments which participated in all surveys showed an increase in MPS count of 11.1 % (PR: 12.2 %, HO: 4.8 %, UH: 18.4 %). 70 % [60 %] of the MPS were requested by ambulatory care cardiologists. CONCLUSION: The 2015 MPS survey reveals a high-grade adherence of routine MPS practice to current guidelines. The positive trend in MPS performance and number of MPS already observed in 2012 continues. Educational training remains necessary in the field of SPECT scoring.

Comparison of the prognostic value of myocardial perfusion imaging using a CZT-SPECT camera with a conventional anger camera.

BACKGROUND: Recent studies have shown that myocardial perfusion imaging (MPI) in cadmium-zinc-telluride (CZT) cameras allow faster exams with less radiation dose but there are little data comparing its prognosis information with that of dedicated cardiac Na-I SPECT cameras OBJECTIVE: The objective of this study is to compare the prognostic value of MPI using an ultrafast protocol with low radiation dose in a CZT-SPECT and a traditional one. METHODS: Group 1 was submitted to a two-day MIBI protocol in a conventional camera, and group 2 was submitted to a 1-day MIBI protocol in CZT camera. MPI were classified as normal or abnormal, and perfusion scores were calculated. Propensity score matching methods were performed RESULTS: 3554 patients were followed during 33±8 months. Groups 1 and 2 had similar distribution of age, gender, body mass index, risk factors, previous revascularization, and use of pharmacological stress. Group 1 had more abnormal scans, higher scores than group 2. Annualized hard events rate was higher in group 1 with normal scans but frequency of revascularization was similar to normal group 2. Patients with abnormal scans had similar event rates in both groups CONCLUSION: New protocol of MPI in CZT-SPECT showed similar prognostic results to those obtained in dedicated cardiac Na-I SPECT camera, with lower prevalence of hard events in patients with normal scan.

The prognostic value of regadenoson SPECT myocardial perfusion imaging in patients with end-stage renal disease.

BACKGROUND: The prognostic value of regadenoson SPECT myocardial perfusion imaging (MPI) has not been specifically studied in patients with end-stage renal disease (ESRD). METHODS AND RESULTS: We prospectively followed ESRD patients enrolled in the ASSUAGE and ASSUAGE-CKD trials in which they received regadenoson-stress 99mTc-tetrofosmin SPECT-MPI. Images were semiquantitatively analyzed by an investigator blinded to clinical and outcome data. Patients were followed for cardiac death, myocardial infarction (MI), and coronary revascularization (CR). Revascularizations occurring >90 days post-MPI were considered "late" events. Survival analysis was performed using Cox regression models, adjusting for age, gender, diabetes, dyslipidemia, smoking, and known coronary artery disease. We analyzed 303 patients (mean age 54 years; 64% men), who were followed for 35 ± 10 months. Adjusting for clinical covariates, abnormal regadenoson-stress MPI (SSS ≥ 4) was associated with increased risk of the composite of cardiac death or MI (23.9% vs 14.4%; HR 1.88; CI 1.04-3.41; P = .037) and the composite of cardiac death, MI, or late CR (27.3% vs 16.7%; HR 1.80; CI 1.03-3.14; P = .039). Adjusting for clinical covariates, regadenoson-induced myocardial ischemia (SDS ≥ 2) was associated with increased rate of the composite endpoint of cardiac death, MI, or CR (33.3% vs 16.9%; HR 1.97; CI 1.19-3.27; P = .008). CONCLUSION: Regadenoson-stress SPECT-MPI provides a significant prognostic value in patients with ESRD. ESRD patients with normal SPECT-MPI have relatively high adverse event rates.

Impact of Appropriate Use on the Estimated Radiation Risk to Men and Women Undergoing Radionuclide Myocardial Perfusion Imaging.

UNLABELLED: The impact of appropriate use criteria (AUC) for myocardial perfusion imaging (MPI) with SPECT on the estimated lifetime attributable risk (LAR) of cancer is unknown. METHODS: A cohort of 1,511 consecutive patients who underwent clinically indicated (99m)Tc-setamibi MPI were categorized into appropriate/uncertain (n = 823) versus inappropriate (n = 688) use groups according to the 2009 AUC and were prospectively followed for 27 ± 10 mo. Logistic regression models were used to determine the annualized probability of major adverse cardiac events (MACE) of cardiac death or myocardial infarction and the probability of revascularization within 6 mo of MPI, accounting for relevant covariates. We determined LAR for each subject on the basis of accepted risk estimates. We calculated MPI's benefit-to-risk ratios, defined by the annualized predicted MACE-to-LAR ratio and the predicted 6-mo-revascularization-to-LAR ratio. RESULTS: During follow-up, there were 22 MACE and 29 6-mo revascularizations. The administered radioactivity and effective radiation doses absorbed were similar between the study groups. Patients with inappropriate MPI had significantly higher LAR (median, 0.08% vs. 0.06%, P < 0.001), lower predicted MACE-to-LAR ratio (median, 1.5 vs. 4.3, P < 0.001), and lower predicted 6-mo-revascularization-to-LAR ratio (median, 5.4 vs. 15.5, P < 0.001). Women had higher LAR (median, 0.08% vs. 0.07%, P < 0.001) and lower predicted MACE-to-LAR ratio (median, 1.9 vs. 3.3, P < 0.001) and 6-mo-revascularization-to-LAR ratio (median, 4.4 vs. 17.5, P < 0.001). However, appropriate/uncertain use negated the difference between men and women in LAR (P = 0.94) and the predicted MACE-to-LAR ratio (P = 0.97). CONCLUSION: Inappropriate MPI use is associated with excess cancer risk and lower MPI's benefit-to-risk ratio. Appropriate/uncertain use neutralizes the sex gap in LAR with MPI.

Appropriate use criteria in clinical routine practice: implications in a nuclear cardiology lab.

The efforts for a broad application of the appropriate use criteria to reduce inappropriate nuclear stress testing have frequently been unsuccessful and the reported rates of inappropriateness have varied widely between studies. We sought to analyze the criteria of clinical appropriateness of a cohort of consecutive patients referred to our nuclear cardiology laboratory to perform stress myocardial perfusion imaging (MPI) and to assess the relationships between test appropriateness and the evaluation of ischaemia. A cohort of 251 consecutive patients, admitted to our Institute from January to March 2015, who underwent stress/rest MPI on a dedicated cardiac camera equipped with cadmium-zinc-telluride detectors, was selected. The level of clinical appropriateness of each MPI test was categorized in each patient according to the AUC criteria. According to the accepted criteria, the majority of the MPI stress-tests could be classified as clinically appropriate (218 of 251, 87 % of the tests), while only 16 (6 %) and 17 (7 %) resulted of uncertain appropriateness or clearly inappropriate, respectively. Of the 251 appropriate tests, 22 (10 %), 65 (30 %), and 131 (60 %) showed the presence of a mild (SDS < 4), moderate (4 ≥ SDS < 7), and severe (SDS ≥ 7) ischemic burden, respectively, while none of the inappropriate test showed moderate-to-severe ischaemia (P < 0.001 for comparisons). The rate of inappropriate MPI tests is considerably low in a high-volume laboratory. Appropriate and inappropriate studies identify patients at high and low probability of significant ischemia, respectively, providing insights on the effects of the level of appropriateness on stress-test results.

Review of Cardiovascular Imaging in the Journal of Nuclear Cardiology in 2015-Part 2 of 2: Myocardial perfusion imaging.

In 2015, the Journal of Nuclear Cardiology (®) published many high-quality articles. In this series, we will summarize key articles that have appeared in the Journal last year to provide for the interested reader a quick review of the advancements that have recently occurred in the field. In the first article of this 2-part series, we concentrated on publications dealing with plaque imaging, cardiac positron emission tomography, computed tomography, and magnetic resonance. This review will focus on myocardial perfusion imaging summarizing advances in the field including in diagnosis, prognosis, and appropriate use.

The influence of clopidogrel on ischemia diagnosed by myocardial perfusion stress testing.

BACKGROUND: Clopidogrel is a platelet adenosine receptor antagonist which can influence coronary vascular tone and thus can potentially interfere with myocardial perfusion imaging. We investigated whether clopidogrel can hamper the diagnosis of ischemia in patients undergoing myocardial perfusion testing. METHODS: Data from a database of 6349 myocardial perfusion stress tests were analyzed. Using a propensity analysis, patients who were taking clopidogrel were compared with patients not taking clopidogrel for the presence of reversible perfusion defects on myocardial single-photon emission computed tomography scans. RESULTS: Of the 6349 tests, the stress technique was adenosine in 2713 patients and exercise in 3636. At the time of the stress test, 277 (4.3%) of the patients were taking clopidogrel. The odds ratio (OR) for patients taking clopidogrel to have a reversible perfusion defect was 2.75 (95% confidence interval [CI] 2.09-3.62; P < .01). After adjusting for the propensity to take clopidogrel, the OR was 1.06 (CI 0.76-1.49; P = .73) for patients undergoing adenosine stress tests and 1.60 (CI 0.85-3.00; P = .14) for patients undergoing exercise stress tests. CONCLUSIONS: We found no evidence that the use of clopidogrel decreases the likelihood of ischemia on adenosine or exercise stress myocardial perfusion scans.