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Purpose of Review: The goal of this article is to review the data supporting the use of fractional flow reserve derived from coronary computed tomography angiography (FFRCT) in patients with chest pain. Review Findings: Numerous clinical trials have demonstrated that the diagnostic accuracy of coronary computed tomography angiography (CCTA) can be improved with the use of FFRCT, primarily due to its superior specificity when compared to CCTA alone. This promising development may help reduce the need for invasive angiography in patients presenting with chest pain. Furthermore, some studies have indicated that incorporating FFRCT into decision-making is safe, with an FFRCT value of ≥ 0.8 being associated with favorable outcomes. While FFRCT has been shown to be feasible in patients with acute chest pain, further large-scale studies are warranted to confirm its utility. Summary: The emergence of FFRCT as a tool for the management of patients with chest pain is promising. However, potential limitations require the interpretation of FFRCT in conjunction with clinical context. [ABSTRACT FROM AUTHOR]

The inferior wall pattern of decreased perfusion with hypermetabolic activity, i.e., perfusion-metabolic mismatch, can be seen in both sarcoidosis and hibernating ischemic myocardium. 2023 Image 6 result: 18F-FDG PET in a patient with cardiac sarcoidosis and hibernating myocardium: A case report In this patient, given the minimal coronary calcification and absence of high-risk plaque features, as well as the active cardiac sarcoidosis, the epicardial coronary disease is most likely due to sarcoidosis-associated coronary artery vasculitis, rather than atherosclerosis. [Extracted from the article]

While being investigated for a carotid bruit, CCTA demonstrated thickening of the ascending aorta, aortic arch and coronary arteries walls (Figures 1 and 2). IgG4-related disease (IgG4-RD) is an autoimmune condition associated with inflammatory processes occurring in almost any anatomic site, including vasculitis of great vessels and coronary arteries. [Extracted from the article]

Objectives: Coronary artery calcium (CAC) scores derived from computed tomography (CT) scans are used for cardiovascular risk stratification. Artificial intelligence (AI) can assist in CAC quantification and potentially reduce the time required for human analysis. This study aimed to develop and evaluate a fully automated model that identifies and quantifies CAC. Methods: Fully convolutional neural networks for automated CAC scoring were developed and trained on 2439 cardiac CT scans and validated using 771 scans. The model was tested on an independent set of 1849 cardiac CT scans. Agatston CAC scores were further categorised into five risk categories (0, 1–10, 11–100, 101–400, and > 400). Automated scores were compared to the manual reference standard (level 3 expert readers). Results: Of 1849 scans used for model testing (mean age 55.7 ± 10.5 years, 49% males), the automated model detected the presence of CAC in 867 (47%) scans compared with 815 (44%) by human readers (p = 0.09). CAC scores from the model correlated very strongly with the manual score (Spearman's r = 0.90, 95% confidence interval [CI] 0.89–0.91, p < 0.001 and intraclass correlation coefficient = 0.98, 95% CI 0.98–0.99, p < 0.001). The model classified 1646 (89%) into the same risk category as human observers. The Bland–Altman analysis demonstrated little difference (1.69, 95% limits of agreement: −41.22, 44.60) and there was almost excellent agreement (Cohen's κ = 0.90, 95% CI 0.88–0.91, p < 0.001). Model analysis time was 13.1 ± 3.2 s/scan. Conclusions: This artificial intelligence–based fully automated CAC scoring model shows high accuracy and low analysis times. Its potential to optimise clinical workflow efficiency and patient outcomes requires evaluation. Key Points: • Coronary artery calcium (CAC) scores are traditionally assessed using cardiac computed tomography and require manual input by human operators to identify calcified lesions. • A novel artificial intelligence (AI)–based model for fully automated CAC scoring was developed and tested on an independent dataset of computed tomography scans, showing very high levels of correlation and agreement with manual measurements as a reference standard. • AI has the potential to assist in the identification and quantification of CAC, thereby reducing the time required for human analysis. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Nuclear Cardiology is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We assessed the left atrial-left ventricular (LA-LV) long axis angulation value as a new measure of LA remodeling, and studied its predictors, its effect on two-dimensional LA volume (2D LAVol) estimation, and optimization techniques for 2D LAVol values. Retrospective electrocardiogram-gated coronary computed tomographic angiograms of 164 consecutive patients were reviewed. The LA–LV angle was measured in reconstructed 3-chamber views, and its predictors were determined. The LAVol measured by the area-length method after image optimization along the LV long axis (AL) and the LA long axis (AC–AL), was compared with that measured by the three-dimensional (3D)-volumetric method. LAVol calculation was modified to minimize differences from the 3D values. LA–LV angles ranged from 0° to 63°. In the univariate analysis, decreasing angulation was significantly associated with increasing LV end-diastolic volume (LVEDV), mitral regurgitation grade, LV and LA anteroposterior dimensions, and decreasing LV ejection fraction (LVEF). On multivariate analysis, increasing LVEDV, MR, and LA anteroposterior dimension inversely correlated with angulation; LVEF was positively correlated. The AL and 3D methods significantly differed only for patients with angles ≤ 29.9°. Conversely, LAVol was overestimated for all angules by AC–AL. Modification of AL LAVol using a regression equation, or by substituting the shortest with the longest and average LA lengths in patients with angles ≤ 29.9° and 30–39.9°, respectively neutralized the difference. The LA–LV angle is a new measure of LA and LV remodeling predicted by LV size and function, MR, and LA-anteroposterior dimension. AL formula modifications based on angulation in LV-optimized views better correlate with the 3D method than LA-view modification. [ABSTRACT FROM AUTHOR]

Background: Rubidium-82 positron emission tomography (82Rb PET) MPI is considered a noninvasive reference standard for the assessment of myocardial perfusion in coronary artery disease (CAD) patients. Our main goal was to compare the diagnostic performance of static rest/ vasodilator stress CT myocardial perfusion imaging (CT-MPI) to stress/ rest 82Rb PET-MPI for the identification of myocardial ischemia. Methods: Forty-four patients with suspected or diagnosed CAD underwent both static CT-MPI and 82Rb PET-MPI at rest and during pharmacological stress. The extent and severity of perfusion defects on PET-MPI were assessed to obtain summed stress score, summed rest score, and summed difference score. The extent and severity of perfusion defects on CT-MPI was visually assessed using the same grading scale. CT-MPI was compared with PET-MPI as the gold standard on a per-territory and a per-patient basis. Results: On a per-patient basis, there was moderate agreement between CT-MPI and PET-MPI with a weighted 0.49 for detection of stress induced perfusion abnormalities. Using PET-MPI as a reference, static CT-MPI had 89% sensitivity (SS), 58% specificity (SP), 71% accuracy (AC), 88% negative predictive value (NPV), and 59% positive predictive value (PPV) to diagnose stress-rest perfusion deficits on a per-patient basis. On a per-territory analysis, CT-MPI had 73% SS, 65% SP, 67% AC, 90.8% NPV, and 34% PPV to diagnose perfusion deficits. Conclusions: CT-MPI has high sensitivity and good overall accuracy for the diagnosis of functionally significant CAD using 82Rb PET-MPI as the reference standard. CT-MPI may play an important role in assessing the functional significance of CAD especially in combination with CCTA. [ABSTRACT FROM AUTHOR]

Purpose of Review: Detecting cardiac amyloid (CA) is challenging. Traditional approaches have not always succeeded in achieving a timely diagnosis. Cardiac magnetic resonance imaging (CMR) has begun to change this, but access to CMR may be limited due to availability or contraindications and may not be considered if clinical suspicion is not high. In contrast, cardiac CT (CCT) is widely available, fast, and has few contraindications. In this review, we will consider the role of CCT to identify CA using anatomy, function, and tissue characteristics. Recent Findings: We discuss the different CT protocols that have been employed and reflect on the emerging data. Summary: It is likely that CCT will complement existing modalities. It will help detect disease sooner and allow therapy to start earlier. Thus, CT may yet shed light on CA and provide a brighter future for patients. [ABSTRACT FROM AUTHOR]

Our aim was to investigate the usefulness of machine learning approaches on linked administrative health data at the population level in predicting older patients' one-year risk of acute coronary syndrome and death following the use of non-steroidal anti-inflammatory drugs (NSAIDs). Patients from a Western Australian cardiovascular population who were supplied with NSAIDs between 1 Jan 2003 and 31 Dec 2004 were identified from Pharmaceutical Benefits Scheme data. Comorbidities from linked hospital admissions data and medication history were inputs. Admissions for acute coronary syndrome or death within one year from the first supply date were outputs. Machine learning classification methods were used to build models to predict ACS and death. Model performance was measured by the area under the receiver operating characteristic curve (AUC-ROC), sensitivity and specificity. There were 68,889 patients in the NSAIDs cohort with mean age 76 years and 54% were female. 1882 patients were admitted for acute coronary syndrome and 5405 patients died within one year after their first supply of NSAIDs. The multi-layer neural network, gradient boosting machine and support vector machine were applied to build various classification models. The gradient boosting machine achieved the best performance with an average AUC-ROC of 0.72 predicting ACS and 0.84 predicting death. Machine learning models applied to linked administrative data can potentially improve adverse outcome risk prediction. Further investigation of additional data and approaches are required to improve the performance for adverse outcome risk prediction. [ABSTRACT FROM AUTHOR]

Purpose of the review: Coronary artery bypass grafting (CABG) is one of the most common major surgical procedures performed. Atherosclerosis however is a progressive condition; it is probably therefore that patients with CABG will represent with ischemic symptoms. The purpose of this review is to provide familiarity with testing in CABG patients to assist clinicians in their decision-making. Recent findings: CT angiography of coronary arteries and grafts (CCTA) has evolved into an alternative approach to diagnose graft disease or occlusion. As such, CCTA may help risk stratify patients post-CABG. CCTA thus joins the armamentarium of traditional functional tests that can be used. The consequences of which type of test is chosen are discussed. Summary: Through discussion of the contemporary literature for imaging in CABG patients, this review will focus on the strengths and weaknesses of both anatomical and functional approaches. It appears that the impact of which index test is chosen is as important post-CABG as it is in patients with suspected CAD. [ABSTRACT FROM AUTHOR]

Coronary artery calcification (CAC) on body CT imaging is considered a coincidental finding in cancer patients. In order to determine the significance of CAC in cancer patients we evaluated the prognostic utility of CAC detected on oncology FDG-PET/CT studies. A retrospective study was performed of consecutive FDG-PET/CT studies from January to March 2011. CAC was identified on the CT portion of FDG/PET-CT studies. Chart review documented statin use, the Framingham risk score (FRS) (includes age, diabetes, hypertension, dyslipidemia and smoking), the primary malignancy and metastases. The primary end point was a composite of death and cardiovascular (CV) events (non-fatal myocardial infarction (MI), PCI or coronary artery bypass surgery (CABG)). 266 patients had a median follow up of 41 months (95% CI 31–56 months). CAC was noted in 140 patients. Based on CAC, potentially 84 patients would have had a change in statin prescribing (p < 0.01). CAC was associated with the primary end point on univariable and multivariable analysis (OR 2.6 (95% CI 1.42–4.77) (p < 0.01). On univariable Kaplan–Meier survival analysis, CAC was associated with decreased survival only in the absence of metastases (p < 0.01). Cox proportional hazard modelling demonstrated CAC was associated with mortality and cardiac events in patients without metastases, whereas FRS was not (For CAC: HR 1.69 (95% CI 1.22–2.35), p = 0.002). CAC is commonly detected with oncology FDG-PET/CT. In cancer patients CAC was associated with an increased risk of clinical events. CAC reduced survival free time in patients without metastases. CAC might therefore be considered more than a coincidentaloma in patients without metastases. [ABSTRACT FROM AUTHOR]

Low-attenuation plaques (LAPs) are associated with an increased risk of cardiovascular mortality and morbidity. South Asians experience poorer cardiovascular outcomes compared to Caucasian populations. We hypothesised that South Asian population has a higher prevalence of LAP compared to Caucasians and this difference predicts major adverse cardiovascular events. 72 Caucasian and 72 Morise score-matched South Asian patients were identified from a cardiac computed tomography angiography (CCTA) registry. Coronary artery plaque subtypes in proximal major epicardial and left main arteries were analysed from CCTA images using pre-determined attenuation ranges in Hounsfield units (HUs): 1 to 30 HU (low attenuation), 31 to 70 HU (intermediate attenuation), 71 to 150 HU (high attenuation), and mean coronary lumen + 2 standard deviations to 1000 HU (calcified). For each analysis, data comparison was performed for plaque volumes after normalising for the corresponding coronary artery outer vessel wall volume. The baseline characteristics and total plaque score of the two cohorts were similar. There were no statistically significant differences in low, intermediate, and high- attenuation, or calcified normalised plaque volumes between Caucasian and Morise score-matched South Asian cohorts. After a mean follow up of 32 months, major adverse cardiovascular events were similar between Caucasians and South Asians. In a Morise score-matched ethnicity study, we found no significant differences in plaque subtypes including LAP in South Asians compared to a Caucasian cohort. Other factors accounting for poor outcomes in South Asians should be investigated. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Nuclear Cardiology is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: The incremental value and optimal utilization of non-invasive testing for prediction of peri-operative cardiac events during non-cardiac surgery are not clear.Methods: A sub-study of VISION-CTA was performed using patients who underwent both coronary computed tomography angiography (CCTA) and nuclear myocardial perfusion imaging (MPI) as part of their pre-operative assessment. CCTA images were compared with MPI to determine the correlation between ischemia and obstructive coronary artery disease (CAD). Patients were followed post-operatively for 30 days and primary outcomes were all-cause death and non-fatal myocardial infarction. The predictive capacity of CCTA and nuclear MPI in predicting peri-operative major adverse cardiac event (MACE) was analyzed.Results: A total of 55 patients (mean age 68.5 ± 8.4 years, 80.0% male) were analyzed. There was a strong correlation between the degree of obstructive CAD and the severity of perfusion abnormalities. Patients with severe CAD (≥ 70% stenosis) had a higher summed stress score than those without severe CAD [4.88 ± 1.22 and 1.30 ± 0.62, respectively (P < .05)]. Similarly summed difference score was significantly higher in patients with severe CAD [1.33 ± 0.46 and 0.17 ± 0.17 (P < .05)]. At 30 days there was a total of 8 (14.5%) MACE. The rate of MACE was higher in patients with severe CAD than those without (20.7% and 7.7%, respectively). Myocardial ischemia appeared to be predictive of MACE with an unadjusted odds ratio of 14.63 (P = .003). The predictive capacity of MPI further improved when only those patients with severe CAD were included (33.00) with a sensitivity, specificity, positive predictive value, and negative predictive value of 100% (79.4-100.0), 72.7% (49.8-89.3), 50.0% (21.1-78.9), and 100% (79.4-100.0), respectively.Conclusion: Although patients with significant obstructive disease are at risk of peri-operative MACE, the absolute event rate is low. Our data, albeit hypothesis generating, suggest that the peri-operative risk may be refined further by employing nuclear MPI in those with obstructive disease on CCTA. [ABSTRACT FROM AUTHOR]

Background: Cardiac magnetic resonance perfusion studies with adenosine stress have shown that splenic response can identify patients with inadequate pharmacologic stress. We investigate the incremental prognostic impact of splenic response ratio (SRR) in patients with normal Rubidium (Rb)-82 PET myocardial perfusion imaging (MPI).Methods: Consecutive patients undergoing dipyridamole Rb-82 PET MPI for the evaluation of coronary artery disease were screened. Spleen and liver Rb-82 activity was measured and the SRR was calculated: SRR = (Spleen stress/Liver stress)/(Spleen rest/Liver rest). Major adverse cardiac events (MACE) were determined at 1 year of follow-up in patients with normal summed stress score and normal summed difference score.Results: Of the 839 patients screened, the spleen was visualized in 703 (84%) of scans. There was significantly higher MACE observed in splenic non-responders vs splenic responders in both the normal SSS (7.8% vs 2.9%, P = .027) and the normal SDS groups (7.4% vs 2.2%, P = .014). In multivariate analysis in patients with normal SDS, splenic response was a significant, independent predictor of MACE (HR 2.97, 95% CI 1.10 to 8.04, P = .033).Conclusions: SRR is a novel imaging metric to identify patients with sub-maximal vasodilator stress and an incremental prognostic marker in patients with normal SDS and SSS (Clinical Trial Registration: https://clinicaltrials.gov/ct2/show/NCT01128023). [ABSTRACT FROM AUTHOR]

Background: A drop in blood pressure (BP) or blunted BP response is an established high-risk marker during exercise myocardial perfusion imaging (MPI); however, data are sparse regarding the prognostic value of BP response in patients undergoing vasodilator stress rubidium-82 (Rb-82) Positron Emission Tomography (PET) MPI.Methods and Results: From the PET Prognosis Multicenter Registry, a cohort of 3413 patients underwent vasodilator stress Rb-82 PET MPI with dipyridamole or adenosine. We used multivariable Cox proportional hazard regression to analyze the association with mortality of four BP variables: stress minus rest systolic BP (∆SBP), stress minus rest diastolic BP (∆DBP), resting systolic BP (rSBP), and resting diastolic BP (rDBP). Covariates that had univariate P values <.10 were entered into the multivariable model. After median 1.7 years follow-up, 270 patients died. In univariate analyses, ∆SBP (P = .082), rSBP (P = .008), and rDBP (P < .001) were of potential prognostic value (P < .10), but ∆DBP was not (P = .96). After adjustment for other clinical and MPI variables, ∆SBP no longer independently predicted mortality (P = .082); only lower rSBP (P = .026) and lower rDBP (P = .045) remained independently prognostic.Conclusions: In patients undergoing vasodilator stress MPI, only lower resting BP is an independent predictor of mortality along with other clinical and MPI variables; BP response does not appear to add to risk stratification in these patients. [ABSTRACT FROM AUTHOR]

Sudden cardiac death (SCD) represents a significant portion of all cardiac deaths. Current guidelines focus mainly on left ventricular ejection fraction (LVEF) as the main criterion for SCD risk stratification and management. However, LVEF alone lacks both sensitivity and specificity in stratifying patients. Recent research has provided interesting data which supports a greater role for advanced cardiac imaging in risk stratification and patient management. In this article, we will focus on nuclear cardiac imaging, including left ventricular function assessment, myocardial perfusion imaging, myocardial blood flow quantification, metabolic imaging, and neurohormonal imaging. We will discuss how these can be used to better understand SCD and better stratify patient with both ischemic and non-ischemic cardiomyopathy. [ABSTRACT FROM AUTHOR]

Recent technological innovations have created new opportunities for the increased adoption of virtual reality (VR) and augmented reality (AR) applications in medicine. While medical applications of VR have historically seen greater adoption from patient-as-user applications, the new era of VR/AR technology has created the conditions for wider adoption of clinician-as-user applications. Historically, adoption to clinical use has been limited in part by the ability of the technology to achieve a sufficient quality of experience. This article reviews the definitions of virtual and augmented reality and briefly covers the history of their development. Currently available options for consumer-level virtual and augmented reality systems are presented, along with a discussion of technical considerations for their adoption in the clinical environment. Finally, a brief review of the literature of medical VR/AR applications is presented prior to introducing a comprehensive conceptual framework for the viewing and manipulation of medical images in virtual and augmented reality. Using this framework, we outline considerations for placing these methods directly into a radiology-based workflow and show how it can be applied to a variety of clinical scenarios. [ABSTRACT FROM AUTHOR]

Background: We evaluated the performance of stress imaging with technetium-99m-labeled tetrofosmin single-photon emission computed tomography (SPECT) and rubidium-82 positron emission tomography (PET) in patients with extreme obesity, defined as body mass index ≥40 kg/m2.Methods: We identified patients with extreme obesity who underwent angiography in our center and either stress SPECT or PET within the previous six months. Cohorts of patients with extreme obesity and a <5% pretest likelihood of CAD who underwent SPECT (N = 25) or PET (N = 25) were also included.Results: In total, 108 patients who underwent SPECT (N = 57) or PET (N = 51) were identified. Scan interpretation was classified as definitely normal or abnormal in 83.3% of PET and 60.5% of SPECT scans, respectively (P < .01). PET demonstrated higher diagnostic accuracy and normalcy rate. PET was found to have higher specificity for the pooled cohort. Similar findings were observed using stenosis cut-offs of ≥50% and ≥70%.Conclusions: In patients with extreme obesity, PET enabled more definitive scan interpretation with less artifact compared to SPECT. PET provided higher diagnostic accuracy and specificity in the detection of obstructive coronary artery disease. [ABSTRACT FROM AUTHOR]

Background: The impact of adopting new single photon emission computed tomography (SPECT) cameras and new reconstruction algorithms on left ventricular (LV) volumes has not been well established. We sought to understand the impact of hardware and software changes on normal LV reference ranges.Methods: Consecutive patients who underwent stress Tc-99m tetrofosmin 8-frame gated SPECT MPI were screened. Patients with a history of myocardial infarction, coronary revascularization, abnormal MPI, or known LV dysfunction/reduced ejection fraction were excluded. A total of 1953 consecutive normal patients, with rest LV end-diastolic volume (EDV) and end-systolic volume (ESV) measurements were analyzed. After stratifying according to sex, LV volumes indexed to body surface area were compared across the different gamma cameras.Results: In a normal population, measurements with CZT were different from those obtained by the dual-headed NaI gamma cameras for LV EDVi (men: 53.6 ± 10.4 vs 48.3 ± 10.2 mL/m(2) and women: 43.3 ± 8.9 vs 37.8 ± 9.3 mL/m(2); P < 0.001) and LV ESVi (men: 21.7 ± 7.0 vs 16.9 ± 6.2 mL/m(2) and women: 13.4 ± 5.3 vs 10.6 ± 4.7 mL/m(2); P < 0.001). Inter- and intra-observer reliability for all measures was excellent. These findings were verified in a prospectively collected cohort. A sub-analysis of LV measurements comparing new resolution recovery and standard reconstruction software revealed no significant differences in LV measures.Conclusion: This study demonstrates that normal references ranges of LV volumes vary between SPECT cameras and confirms the need for establishing reference values that are camera specific. [ABSTRACT FROM AUTHOR]

Background: Cardiac CT is a non-invasive modality with the ability to estimate LVEF. However, given its limited temporal resolution and radiation, there has been initial resistance to use CT to measure LVEF. Developing an accurate, fast, low radiation dose protocol is desirable.Objective: The objective of this study is to demonstrate that a 'low radiation dose' 64 slice cardiac computed tomography (CT) protocol is feasible and can accurately measure left ventricular ejection fraction (LVEF) while delivering a radiation dose lower than radionuclide angiography (RNA).Methods: Patients undergoing RNA were prospectively screened and enrolled to undergo a 'low-dose' 64 slice CT LVEF protocol. LVEF measures, duration of each study and radiation dose between CT and RNA were compared.Results: A total of 77 patients (mean age = 61.8 ± 12.2 years and 58 men) were analyzed. The mean LVEF measured by CT and RNA were 41.9 ± 15.2% and 39.4 ± 13.9%, respectively, (P = 0.154) with a good correlation (r = 0.863). Bland-Altman plot revealed a good agreement between the CT and RNA LVEF (mean difference of -2.4). There was good agreement between CT LVEF and RNA for identifying patients with LVEF ≤30% (kappa = 0.693) and LVEF ≥50% (kappa = 0.749). The mean dose estimated effective dose for CT and RNA were 4.7 ± 1.6 and 9.5 ± 1.0 mSv, respectively. The mean CT LVEF imaging duration (4:32 ± 3:05 minutes) was significantly shorter than the RNA image acquisition time (9:05 ± 2:36 minutes; p < 0.001).Conclusion: The results of our study suggest that low-dose CT LVEF protocol is feasible, accurate, and fast while delivering a lower radiation dose than traditional RNA. [ABSTRACT FROM AUTHOR]

Purpose: Contrast-induced acute kidney injury is a prominent complication following cardiac catheterization, though the risk has progressively decreased in recent times with appropriate risk stratification and use of safer contrast agents. Despite data supporting further lowering of risk with the iso-osmolar agent, iodixanol, uptake has lagged, perhaps due to increased upfront cost of this agent. We undertook an economic analysis to estimate the cost-effectiveness of a strategy utilizing iodixanol compared to using a low-osmolar contrast agent.Methods: We created a Markov model to evaluate the two strategies, and included a differential relative risk of contrast-induced acute kidney injury, based on a systematic review of the literature. Downstream clinical events, including need for dialysis and mortality, were modeled using data from existing published literature. A third-party payer perspective was utilized for the analysis and presentation of the primary economic analysis.Results: The strategy of using iodixanol dominated in both the low-risk and high-risk base case analyses. However, the difference was quite small in the low-risk scenario (lifetime cost: C$678,034 vs. C$678,059 and life expectancy: 19.80 vs. 19.72 years). The difference was more marked (life expectancy 15.65 vs. 14.15 years and cost C$680,989 vs. C$682,023) in the high-risk case analysis. This was robust across most of the variables tested in sensitivity analyses.Conclusion: The use of iodixanol, compared with low-osmolar contrast agents, for cardiac catheterization, results in a small benefit clinical outcomes, and in a savings in direct healthcare costs. Overall, our analysis supports the use of iodixanol for cardiac catheterization, especially in patients at high risk of acute kidney injury. [ABSTRACT FROM AUTHOR]

Background: Prognostic value of positron emission tomography (PET) myocardial perfusion imaging (MPI) is well established. There is paucity of data on how the prognostic value of PET relates to the hemodynamic response to vasodilator stress. We hypothesize that inadequate hemodynamic response will affect the prognostic value of PET MPI.Methods and results: Using a multicenter rubidium (Rb)-82 PET registry, 3406 patients who underwent a clinically indicated rest/stress PET MPI with a vasodilator agent were analyzed. Patients were categorized as, “responders” [increase in heart rate ≥ 10 beats per minute (bpm) and decrease in systolic blood pressure (SBP) ≥10 mmHg], “partial responders” (either a change in HR or SBP), and “non-responders” (no change in HR or SBP). Primary outcome was all-cause death (ACD), and secondary outcome was cardiac death (CD). Ischemic burden was measured using summed stress score (SSS) and % left ventricular (LV) ischemia. After a median follow-up of 1.68 years (interquartile range = 1.17- 2.55), there were 7.9% (n = 270) ACD and 2.6% (n = 54) CD. Responders with a normal PET MPI had an annualized event rate (AER) of 1.22% (SSS of 0-3) and 1.58% (% LV ischemia = 0). Partial and non-responders had higher AER with worsening levels of ischemic burden. In the presence of severe SSS ≥12 and LV ischemia of ≥10%, partial responders had an AER of 10.79% and 10.36%, compared to non-responders with an AER of 19.4% and 12.43%, respectively. Patient classification was improved when SSS was added to a model containing clinical variables (NRI: 42%, p < 0.001) and responder category was added (NRI: 61%, p < 0.001). The model including clinical variables, SSS and hemodynamic response has good discrimination ability (Harrell C statistics: 0.77 [0.74-0.80]).Conclusion: Hemodynamic response during a vasodilator Rb-82 PET MPI is predictive of ACD. Partial and non-responders may require additional risk stratification leading to altered patient management. [ABSTRACT FROM AUTHOR]

Acute coronary syndromes are most often the result of vulnerable atherosclerotic plaque events. Plaques events occur when intimal fibroatheroma in the coronary artery wall becomes vulnerable to erosion or rupture. Such vulnerable plaques can be distinguished from quiescent atheroma by features that have been defined through histopathology and invasive imaging. A challenge for coronary CT angiography has been to identify vulnerable plaques non-invasively. Were this possible, CT angiography could offer comprehensive vessel assessment including stenosis severity and plaque characteristics with the hope of reducing acute coronary events through timely intervention. Over the past decade, advances in invasive imaging techniques have enabled unstable coronary plaques to be accessed more readily. In this fashion it has been possible to correlate invasive appearances to CT angiographic findings in an unprecedented manner. Several CT defined plaque characteristic have now been described to reliably identify unstable plaques. Retrospective studies have demonstrated the utility of these plaque features to predict future acute coronary events. If these can be confirmed in prospective studies, the intrinsic benefits of non-invasive imaging will position coronary CT angiography firmly in our armamentarium to image coronary arteries and help prevent acute coronary events. [ABSTRACT FROM AUTHOR]

Background: Coronary artery calcium is an important marker of coronary artery disease. Myocardial perfusion imaging (MPI) using PET-CT technology requires a CT scan for attenuation correction (CTAC) but is not used routinely to measure coronary calcium burden. This study aimed to determine if a low-dose CTAC scan can also accurately quantify coronary artery calcium. Methods: Twenty-three patients underwent both a traditional coronary artery calcium scan on a dedicated cardiac CT scanner (CAC-CT) and a myocardial perfusion scan on a hybrid PET-CT scanner. The standard MPI protocol includes rest and stress-matched PET and CTAC scans. The post-stress CTAC scan was modified to approximate the CAC-CT scan protocol while maintaining ~0.5 mSv dose. Coronary artery calcium scores were compared between the Ca-CTAC and CAC-CT scans. Results: The modified Ca-CTAC scan showed a trend toward slight decreases in segmental stress perfusion of 2-3.5% in the anterior wall segments ( P < 0.05). Correlation and agreement between the proposed Ca-CTAC and standard CAC-CT calcium scores at the optimal threshold of 110 HU were also excellent ( r = 0.99, κ = 1.0). There was a small difference in the regression slope vs unity: Ca-CTAC = 0.96 × CAC ( P < 0.05), but the categorical classification of calcium was accurate in all twenty-three patients (κ = 1.0). Conclusion: A single low-dose rest CTAC scan can be used for accurate attenuation correction of rest and stress PET perfusion images, thus allowing a post-stress CTAC scan to be optimized for improved quantification of coronary artery calcium without increasing radiation dose vs standard protocols. [ABSTRACT FROM AUTHOR]

The inverse relationship between obesity and adverse cardiovascular outcomes has been coined the 'obesity-paradox'. We sought to determine the relationship between measures of obesity [body mass index (BMI), body surface area (BSA) and body fat percentage (BF%)] and coronary artery calcification (CAC). We retrospectively analyzed patients who underwent CAC using the Agatston score. Baseline demographics were collected and BMI, BSA and BF% were calculated. A two-stage regression modeling approach was used to evaluate the association between BMI, BSA, BF% and Agatston score. Of the 6661 patients [mean age = 57.1 ± 10.8 years, men = 54.3 %, median Agatston score = 14 (0, 163)], 0.1 % were underweight, 21.3 % had normal BMI, 39.1 % were overweight and 39.4 % were obese. The mean BMI, BSA and BF% were 29.6 ± 6.1 kg/m, 1.97 ± 0.25 m and 37 ± 10 %, respectively. There was an independent association between the presence of CAC and BMI (5 kg/m increments) (OR 1.05, CI 1.00-1.11, P = 0.038) and BF% (OR 2.38, CI 1.05-5.41, P = 0.038). Neither BMI categories nor large BSA independently predicted the presence of CAC. BF% predicted the extent of CAC in men but not in women, and higher BF% was associated with higher category of CAC severity in men only. BMI and BF% were independent predictors of the presence of CAC. BF% was associated with the extent of CAC and higher BF% was associated with higher category of CAC severity in men only. These results suggest that further study is needed to better understand the obesity-paradox. [ABSTRACT FROM AUTHOR]

Obesity is reaching pandemic proportions, and its prevalence is projected to increase over the next decade. Because of the strong association of obesity and cardiovascular disease, the demand for diagnostic and prognostic tests is also expected to increase. Although there are multiple imaging modalities available for the physician, appropriate selection of the imaging modality in obese patients will facilitate accurate diagnosis, patient management, and minimize unnecessary resource utilization and costs. To help select the most appropriate imaging modality in obese patients, it is vital that the physician understands the limitations of each imaging modality. Positron emission tomography (PET) cameras and radiotracers have unique characteristics that offer advantages over other modalities. Qualitative assessment of relative myocardial perfusion and quantification of myocardial blood flow by PET is feasible. Therefore, PET may be an ideal imaging modality in obese patients. [ABSTRACT FROM AUTHOR]

Background: Coronary artery calcium (CAC) is a well-established predictor of clinical outcomes for population screening. Limited evidence is available as to its predictive value in symptomatic patients without obstructive coronary artery disease (CAD). The aim of the current study was to assess the prognostic value of CAC scores among symptomatic patients with nonobstructive CAD. Methods: From the COronary Computed Tomographic Angiography EvaluatioN For Clinical Outcomes: An InteRnational Multicenter (CONFIRM) registry, 7,200 symptomatic patients with nonobstructive CAD (<50% coronary stenosis) on coronary-computed tomographic angiography were prospectively enrolled and followed for a median of 2.1 years. Patients were categorized as without (0% stenosis) or with (>0% but <50% coronary stenosis) a luminal stenosis. CAC scores were calculated using the Agatston method. Univariable and multivariable Cox proportional hazard models were employed to estimate all-cause mortality and/or myocardial infarction (MI). Four-year death and death or MI rates were 1.9% and 3.3%. Results: Of the 4,380 patients with no luminal stenosis, 86% had CAC scores of <10 while those with a luminal stenosis had more prevalent and extensive CAC with 31.9% having a CAC score of ≥100. Among patients with no luminal stenosis, CAC was not predictive of all-cause mortality ( P = .44). However, among patients with a luminal stenosis, 4-year mortality rates ranged from 0.8% to 9.8% for CAC scores of 0 to ≥400 ( P < .0001). The mortality hazard was 6.0 ( P = .004) and 13.3 ( P < .0001) for patients with a CAC score of 100-399 and ≥400. In patients with a luminal stenosis, CAC remained independently predictive in all-cause mortality ( P < .0001) and death or MI ( P < .0001) in multivariable models containing CAD risk factors and presenting symptoms. Conclusions: CAC allows for the identification of those at an increased hazard for death or MI in symptomatic patients with nonobstructive disease. From the CONFIRM registry, the extent of CAC was an independent estimator of long-term prognosis among symptomatic patients with luminal stenosis and may further define risk and guide preventive strategies in patients with nonobstructive CAD. [ABSTRACT FROM AUTHOR]

Background: An impaired chronotropic response to exercise is an accepted risk marker but the relationship between heart rate reserve (HRR) with pharmacologic stress is less well-established. The primary aim of this analysis was to evaluate the prognostic significance of HRR in patients undergoing rest/stress myocardial perfusion positron emission tomography (PET) in estimating coronary artery disease (CAD) mortality. Methods: This subset analysis from the PET Prognosis Multicenter Registry includes a total of 2,398 patients undergoing rest/stress Rb-PET from three participating sites. The HRR from rest to peak stress was categorized into tertiles of ≤4, 5-14, and ≥15 beats per minute (bpm). At stress, the % abnormal myocardium was categorized as <5 %, 5-9.9 %, and ≥10 %. We estimated CAD mortality using univariable and multivariable Cox proportional hazard models. Results: CAD mortality was 12.8 %, 3.4 %, and 0.8 %, respectively, for HRR measurements of ≤4, 5-14, and ≥15 bpm ( P < 0.0001). In a multivariable model, the HRR was independently predictive of CAD mortality ( P < 0.0001) with adjusted hazard ratios elevated 3.5- and 8.4-fold for HRR of 5-14 and ≤4 versus ≥15 bpm. In a multivariable model, both the HRR and stress MPI % abnormal myocardium were independently and highly predictive of CAD mortality. Moreover, the net reclassification improvement was 0.18 for the HRR when compared to a model including risk factors, symptoms, rest HR, and PET variables ( P = 0.0008). For those with ≥10 % abnormal myocardium on stress PET, there was a graded relationship between HRR and CAD mortality with adjusted hazards exceeding 50-fold for measurements of 5-14 and ≤4 bpm ( P < 0.0001) compared to stress MPI with <5 % abnormal myocardium and a HRR ≥15 bpm. Conclusion: A diminished HRR to vasodilator stress is a novel but increasingly important predictor of CAD mortality. HRR measurements of ≤4, 5-14, and ≥15 bpm were independently predictive of CAD mortality and underscore the importance of optimizing readily available novel markers of risk as highly relevant to identifying high and low risk patient subsets. [ABSTRACT FROM AUTHOR]

Background: Short-term risk scores, such as the Framingham risk score (FRS), frequently classify younger patients as low risk despite the presence of uncontrolled cardiovascular risk factors. Among patients with low FRS, estimation of lifetime risk is associated with significant differences in coronary arterial calcium scores (CACS); however, the relationship of lifetime risk to coronary atherosclerosis on coronary CT angiography (CCTA) and prognosis has not been studied. Methods and Results: We evaluated asymptomatic 20-60-year-old patients without diabetes or known coronary artery disease (CAD) within an international CT registry who underwent ≥64-slice CCTA. Patients with low FRS (<10%) were stratified as low (<39%) or high (≥39%) lifetime CAD risk, and compared for the presence and severity of CAD and prognosis for death, myocardial infarction, and late coronary revascularization (>90 days post CCTA). 1,863 patients of mean age of 47 years were included, with 48% of the low FRS patients at high lifetime risk. Median follow-up was 2.0 years. Comparing low-to-high lifetime risk, respectively, the prevalence of any CAD was 32% vs 41% ( P < .001) and ≥50% stenosis was 7.4% vs 9.6% ( P = .09). For those with CAD, subjects at low vs high lifetime risk had lower CACS (median 12 [IQR 0-94] vs 38 [IQR 0.05-144], P = .02) and less purely calcified plaque, 35% vs 45% ( P < .001). Prognosis did not differ due to low number of events. Conclusion: Assessment of lifetime risk among patients at low FRS identified those with the increase in CAD prevalence and severity and a higher proportion of calcified plaque. [ABSTRACT FROM AUTHOR]

Objective: To determine if increased epicardial adipose tissue (EAT) measured by cardiac CT could be associated with impaired myocardial flow reserve (MFR) in patients with non-obstructive coronary artery disease (CAD). Background: Studies have shown that EAT volume is related to epicardial obstructive CAD, myocardial ischemia and major adverse cardiac events. However, the association between EAT with coronary microvascular dysfunction and impaired MFR has not been well clarified. Methods: Consecutive patients who underwent Rb-82 positron emission tomography (PET), coronary artery calcium (CAC) scoring and non-invasive coronary computed tomography angiography (CCTA) were screened. PET scans were analysed for standard myocardial perfusion (MPI) and MFR. CCTA results were analysed and only patients with non-obstructive CAD (<50% luminal diameter stenosis) were included. EAT thickness and volumes were measured from CT scans. Results: Of 137 patients without obstructive CAD by CCTA and with normal Rb-82 PET relative MPI, 26 (19.0%) patients had impaired MFR < 2 and 87 (64%) patients had CAC. EAT, EAT and CAC values were higher in patients with impaired MFR < 2 than those with normal MFR ≥ 2 (6.7 ± 1.6 mm vs 4.4 ± 1.0 mm, P < .0001; 119.0 ± 25.3 cm vs 105.8 ± 30.5 cm, P < .04 and 508.9 ± 554.3 vs 167.8 ± 253.9, P < .0001, respectively). However, EAT had a stronger negative correlation with MFR than EAT and CAC ( r = −0.78 vs r = −0.25 and ρ = −0.32, P < .0001). With multivariable logistic regression analysis, only EAT was independently associated with impaired MFR (OR 20.7, 95% CI 4.9-87.9, P < .0001). Importantly, the receiver-operator characteristic (ROC) curves demonstrated a superior performance of EAT vs EAT and EAT vs CAC in detecting impaired MFR (AUC: 0.945 vs 0.625, difference between AUC: 0.319, P < .0001; AUC: 0.945 vs 0.710, difference between AUC: 0.235, P < .0006, respectively). On ROC curve analysis, an EAT cut-off value > 5.6 mm was optimal in detecting impaired MFR with a sensitivity and specificity of 81% and 92%, respectively. Conclusions: Increased EAT appears to be associated with impaired MFR. This parameter may help improve detection of patients at risk of microvascular dysfunction. [ABSTRACT FROM AUTHOR]

Background: Though myocardial perfusion imaging (MPI) with single-photon emission computed tomography (SPECT) is an established diagnostic method, equivocal studies are commonly encountered. New software has been introduced that incorporates resolution recovery (RR) and noise regulation into the reconstruction algorithm and has been used to facilitate 'half-dose' and 'half-time' studies. Its utility with 'full-time, full-dose' acquisition has not been well studied. Objective: We sought to understand the potential benefit of incorporating RR software in equivocal SPECT studies. Methods: Patients with full-time, full-dose SPECT MPI were reviewed and those with equivocal results, who subsequently underwent cardiac Rb-82 positron emission tomography (PET) scan were identified. Image reconstruction was performed with iterative reconstruction (IR), attenuation correction (IR + AC), and RR software (IR + AC + RR). Images were anonymized and read blindly by consensus of two experienced readers. All images were qualitatively assessed and semi-quantitatively graded using summed stress and summed rest scores. Results: 45 patients were included (28 males, age = 59.6 ± 9.9 years) and the diagnostic accuracy of each of the reconstruction algorithms (IR, IR + AC, IR + AC + RR) was compared to Rb-82 PET. Agreement of clinical diagnosis of each SPECT reconstruction with Rb-PET showed incremental improvement. The agreement with PET for IR + AC + RR ( κ = 0.66, CI 0.454-0.875) is significantly better than for IR (κ = 0.22, CI 0.0-0.450, P = .005) and for IR + AC (κ = 0.32, CI 0.077-0.563, P = .03). Also, IR + AC + RR improved the clinical diagnosis in 14 cases and with overall improvement of reclassification proportion of 23.5% compared to IR ( P = .01). Using PET as a reference standard, ROC curves were created for IR + AC + RR, IR + AC, and IR which showed incremental value of the area under the curve of IR + AC + RR (AUC: 0.87; CI 0.76-0.98) over IR + AC (AUC: 0.75; CI 0.61-0.89, P = .078), and over IR (AUC 0.68; CI 0.52-0.84, P = .025). Conclusion: The addition of RR may help in the diagnosis of patients with equivocal SPECT MPI without the need for additional testing. Further prospective studies are needed to define the role of this new software. [ABSTRACT FROM AUTHOR]

Non-invasive cardiac imaging is pivotal in the diagnosis and prognosis of patients with stable CAD. Nuclear SPECT, PET, stress echocardiography and more recently cardiac magnetic resonance imaging have been utilized with excellent diagnostic accuracy. However, along with their inherent individual limitations, most modalities detect ischemia but lack the ability to define coronary anatomy or evaluate for subclinical atherosclerosis. A modality that not only accurately diagnoses obstructive CAD and also facilitates early identification of non-obstructive CAD may be of interest because it may allow for earlier aggressive risk factor modification and primary prevention. Cardiac computerized tomographic angiography (CCTA) has the potential to accurately detect or exclude luminal stenosis, as well as identify and quantify subclinical atherosclerosis in the absence if luminal narrowing. However CCTA, being a relatively a new modality, has less supporting evidence when compared to more mature modalities such as SPECT. Therefore, the question that begs to be addressed is whether CCTA can be utilized as a first line test in establishing the diagnosis and prognosis of CAD. [ABSTRACT FROM AUTHOR]

Coronary computed tomographic angiography (CCTA) employing CT scanners of 64-detector rows or greater represents a novel non-invasive method for detection of coronary artery disease (CAD), providing excellent diagnostic information when compared to invasive angiography. In addition to its high diagnostic performance, prior studies have shown that CCTA can provide important prognostic information, although these prior studies have been generally limited to small cohorts at single centers. The Coronary CT Angiography Evaluation for Clinical Outcomes: An International Multicenter registry, or CONFIRM, is a large, prospective, multinational, dynamic observational cohort study of patients undergoing CCTA. This registry currently represents more than 32,000 consecutive adults suspected of having CAD who underwent ≥64-detector row CCTA at 12 centers in 6 countries between 2005 and 2009. Based on its large sample size and adequate statistical power, the data derived from CONFIRM registry have and will continue to provide key answers to many important topics regarding CCTA. Based on its multisite international national design, the results derived from CONFIRM should be considered as more generalizable than prior smaller single-center studies. This article summarizes the current status of several studies from CONFIRM registry. [ABSTRACT FROM AUTHOR]

Background: Relative myocardial perfusion imaging (MPI) is the standard imaging approach for the diagnosis and prognostic work-up of coronary artery disease (CAD). However, this technique may underestimate the extent of disease in patients with 3-vessel CAD. Positron emission tomography (PET) is also able to quantify myocardial blood flow. Rubidium-82 (Rb) is a valid PET tracer alternative in centers that lack a cyclotron. The aim of this study was to assess whether assessment of myocardial flow reserve (MFR) measured with Rb PET is an independent predictor of severe obstructive 3-vessel CAD. Methods: We enrolled a cohort of 120 consecutive patients referred to a dipyridamole Rb PET MPI for evaluation of ischemia neither with prior coronary artery bypass graft nor with recent percutaneous coronary intervention that also underwent coronary angiogram within 6 months of the PET study. Patients with and without 3-vessel CAD were compared. Results: Among patients with severe 3-vessel CAD, MFR was globally reduced (<2) in 88% (22/25). On the adjusted logistic Cox model, MFR was an independent predictor of 3-vessel CAD [.5 unit decrease, HR: 2.1, 95% CI (1.2-3.8); P = .015]. The incremental value of Rb MFR over the SSS was also shown by comparing the adjusted SSS models with and without Rb MFR ( P = .005). Conclusion: Rb MFR is an independent predictor of 3-vessel CAD and provided added value to relative MPI. Clinical integration of this approach should be considered to enhance detection and risk assessment of patients with known or suspected CAD. [ABSTRACT FROM AUTHOR]

A single imaging modality that can accurately assess both coronary anatomy and mitral valve (MV) anatomy prior to surgery may be desirable. We sought to determine the diagnostic accuracy of cardiac computed tomography (CT) to detect and characterize mitral valve prolapse (MVP) compared to echocardiography. Consecutive patients referred for 'single-source' cardiac CT for investigation prior to non-coronary cardiac sugery were identified. MV anatomy was assessed for MVP and results were compared to echocardiography and to intra-operative visual assessment of the MV. Comparison between the three modalities was performed at the per-patient, per-leaflet and per-scallop levels. A total of 67 consecutive patients that were referred for Cardiac CT prior to non-coronary cardiac surgery and were prospectively recruited into a Cardiac CT registry. Of these, 65 patients underwent cardiac surgery. 63 patients had echocardiography and 32 patients had intra-operative visual assessment of the mitral valve. Compared to echocardiography, cardiac CT had excellent sensitivity (92.6%) and specificity (97.1%) for the detection of any MVP, but had poor sensitivity (68.5%) for the detection of individual prolapsing scallop. Compared to intra-operative visual assessment of the prolapsing scallop, both cardiac CT and echocardiography had low sensitivity (58.1 and 78.1%, respectively). Cardiac CT was able to identify patients with MVP but had difficulty identifying the prolapsed scallops compared to echocardiography. Single-source CT may not be ready for characterization of individual mitral valve scallops. [ABSTRACT FROM AUTHOR]

Cardiac computed tomography (CT) is a non-invasive modality that is commonly used as an alternative to invasive coronary angiography for the investigation of coronary artery disease. The enthusiasm for this technology has been tempered by a growing appreciation of the potential risks of malignancy associated with the use of ionising radiation. In the spirit of minimizing patient risk, the medical profession and industry have worked hard to developed methods and protocols to reduce patient radiation exposure while maintaining excellent diagnostic accuracy. A complete understanding of radiation reduction techniques will allow clinicians to reduce patient risk while providing an important diagnostic service. This review will consider the established and emerging techniques that may be adopted to reduce patient absorbed doses from x-ray CT. By modifying (1) x-ray tube output, (2) imaging time (scan duration), (3) imaging distance (scan length) and (4) the appropriate use of shielding, clinicians will be able to adhere to the 'as low as reasonably achievable (ALARA)' principle. [ABSTRACT FROM AUTHOR]

Altered sympathetic nervous system signaling is known to play a role in the cardiotoxicity of the anthracycline chemotherapeutic agents, but the interaction of pre- and postsynaptic function is not well understood. Our aim was to study the noradrenergic signaling in an established rat model of adriamycin cardiotoxicity (15 mg/kg administered i.p. over 2 weeks) using radiotracers having potential applicability for imaging with positron emission tomography (PET). Ex vivo biodistribution was performed 1 and 3 weeks post-adriamycin treatment with the noradrenaline analogue [11C] meta-hydroxyephedrine ([11C]HED), β-adrenergic receptor antagonist [3H]CGP12177, and phosphodiesterase-4 inhibitor ( R)-[11C]rolipram. Cardiac function (echocardiographic parameters) and heart/body weight ratio were not affected. Myocardial retention of [11C]HED, [3H]CGP12177, and ( R)-[11C]rolipram were unchanged 1 week post-adriamycin. Compared to controls, 3 weeks post-treatment [3H]CGP12177 uptake decreased (left ventricle free wall and septum; P < 0.05), while [11C]HED and ( R)-[11C]rolipram uptake were unaffected. Following acute increase in myocardial noradrenaline levels with desipramine treatment, ( R)-[11C]rolipram retention increased in the left atrium, right ventricle, left ventricle free wall and septum ( P < 0.05) in vehicle-, but not adriamycin-treated animals. Our results suggest that adriamycin-induced toxicity exhibits no change in presynaptic noradrenaline uptake, but decreased β-adrenergic receptors in cardiac tissues, supporting a role for PET imaging of noradrenaline signaling in the study of anthracycline cardiotoxicity. [ABSTRACT FROM AUTHOR]

Relative myocardial perfusion imaging may underestimate severity of coronary disease (CAD), particularly in cases of balanced ischemia. Can quantification of peak left (LV) and right (RV) ventricular Rb-82 uptake measurements identify patients with left main or 3 vessel disease? Patients (N = 169) who underwent Rb-82 PET MPI and coronary angiography were categorized as having no significant coronary stenosis (n = 60), 1 or 2 vessel disease (n = 81), or left main disease/3 vessel disease (n = 28), based on angiography. Maximal LV and RV ventricular myocardial Rb-82 uptake was measured during stress and rest. Failure to augment LV uptake by ≥ 8500 Bq/cc at stress, predicted left main or 3 vessel disease with a sensitivity of 93% and specificity of 61% (area under curve = 0.83). A ≥10% increase in RV: LV uptake ratios with stress over rest was 93% specific (area under curve = 0.74) for left main or 3 vessel disease. These indices incrementally predicted left main or 3 vessel disease compared to models including age, gender, cardiac risk factors, and summed stress and difference scores. Quantifying maximal rest and stress LV and RV uptake with PET myocardial perfusion imaging may independently and incrementally identify patients with left main or 3 vessel disease. [ABSTRACT FROM AUTHOR]

Cardiovascular disease is the leading cause of mortality and morbidity in developed countries. Evidence challenges the notion that the severity of lesions on angiography is a predictor of future cardiac events. With the recognition that subclinical coronary artery stenoses are responsible for myocardial infarcts and sudden death, it may be important to identify patients with plaque characteristics that may place them at increased risk. Intravascular ultrasound, though invasive, remains the current imaging gold standard. Computed tomography, cardiac magnetic resonance, and single-photon emission CT positron emission tomography are evolving and promising modalities. Functional studies reflecting plaque temperature and molecular imaging reflecting plaque constituents are being developed. We review the pathology of the vulnerable atherosclerotic plaque and recent innovations in imaging modalities to assess plaque complication risk. [ABSTRACT FROM AUTHOR]

Purpose of the Review: Risk assessment for ischemic cardiac complications post noncardiac surgery is not an exact science. This often prompts physicians to order investigations for further risk stratification. As a diagnostic text coronary CT angiography (CCTA)* could prove to be a useful adjunct in preoperative risk assessment and its utility in this setting will be considered.Recent Findings: CCTA has been used to assess preoperative risk in several clinical studies, including the recent CTA VISION trial. CTA VISION suggested, in the cohort examined, that CCTA could lead to an exaggeration of preoperative risk. Whether this is true in other populations will be considered.Summary: In this review, the results from CTA VISION and the recently published Canadian Cardiovascular Society guidelines will be considered in the context of previous literature and current international guidelines. [ABSTRACT FROM AUTHOR]