The impact of moderate aortic stenosis in acute myocardial infarction: A multicenter retrospective study.

BACKGROUND: Aortic stenosis (AS) is associated with myocardial ischemia through different mechanisms and may impair coronary arterial flow. However, data on the impact of moderate AS in patients with acute myocardial infarction (MI) is limited. AIMS: This study aimed to investigate the impact of moderate AS in patients presenting with acute myocardial infarction (MI). METHODS: We conducted a retrospective analysis of all patients who presented with acute MI to all Mayo Clinic hospitals, using the Enterprise Mayo PCI Database from 2005 to 2016. Patients were stratified into two groups: moderate AS and mild/no AS. The primary outcome was all cause mortality. RESULTS: The moderate AS group included 183 (13.3%) patients, and the mild/no AS group included 1190 (86.7%) patients. During hospitalization, there was no difference between both groups in mortality. Patients with moderate AS had higher in-hospital congestive heart failure (CHF) (8.2% vs. 4.4%, p = 0.025) compared with mild/no AS patients. At 1-year follow-up, patients with moderate AS had higher mortality (23.9% vs. 8.1%, p < 0.001) and higher CHF hospitalization (8.3% vs. 3.7%, p = 0.028). In multivariate analysis, moderate AS was associated with higher mortality at 1-year (odds ratio 2.4, 95% confidence interval [1.4-4.1], p = 0.002). In subgroup analyses, moderate AS increased all-cause mortality in STEMI and NSTEMI patients. CONCLUSION: The presence of moderate AS in acute MI patients was associated with worse clinical outcomes during hospitalization and at 1-year follow-up. These unfavorable outcomes highlight the need for a close follow-up of these patients and for timely therapeutic strategies to best manage these coexisting conditions.

Echocardiography in Cardiac Assist Devices.

In patients with medically refractory heart failure or cardiogenic shock, both temporary and durable mechanical circulatory support devices can be used to support cardiac circulation. Both transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE) are widely available, relatively noninvasive, and avoid radiation exposure. Thus, echocardiography is an invaluable tool that provides vital information aiding in preprocedure evaluation, placement, management, and weaning of cardiac assist devices. The purpose of this article is to review the utility of both TTE and TEE in managing patients with cardiac assist devices.

National Cardiovascular Data Registry Model Predicts Long-Term Mortality in Patients Undergoing Percutaneous Coronary Interventions.

National Cardiovascular Data Registry (NCDR)-based logistic regression model is available for clinicians to predict in-hospital all-cause mortality after a percutaneous coronary intervention (PCI). However, this model has never been used to predict long-term all-cause mortality after PCI. Therefore, we sought to test the ability of the NCDR model to predict the short- and long-term risk of all-cause mortality in patients undergoing PCI. All patients undergoing PCI in the Mayo Clinic Health System were enrolled in the Mayo Clinic CathPCI registry. Patient-level demographic, clinical, and angiographic data from January 2006 to December 2017 were extracted from the registry. Patients who underwent coronary artery bypass graft surgery (CABG) were excluded. The area under the receiver operator characteristic curve (AUC) was calculated to assess the ability of the NCDR model to predict outcomes of interest (6-month, 1-year, 2-year, and 5-year all-cause mortality) after PCI. A total of 17,356 unique patients were included for the final analysis after excluding 165 patients who underwent CABG surgery. The mean age was 66.9 ± 12.5 years, and 71% were men. The 6-month, 1-year, 2-year, and 5-year all-cause mortality rates were 4.2% (n = 737), 5.8% (n = 1,005), 8.06% (n = 1,399), and 14.2% (n = 2,472), respectively. The AUCs of the NCDR model to predict 6-month, 1-year, 2-year, and 5-year all-cause mortality were 0.84 (95% CI: 0.82-0.86), 0.82 (95% CI: 0.80-0.84), 0.80 (95% CI: 0.79-0.81), and 0.78 (95% CI: 0.77-0.79), respectively. The NCDR model was able to accurately predict both short- and long-term all-cause mortality after PCI.

Advanced Nuclear Medicine and Molecular Imaging in the Diagnosis of Cardiomyopathy.

OBJECTIVE. The purpose of this article is to summarize the protocol, interpretation, and diagnostic performance of nuclear medicine and molecular imaging in imaging two distinctive, underdiagnosed cardiomyopathies: cardiac amyloidosis and cardiac sarcoidosis. CONCLUSION. Emerging new radiotracers and advanced molecular imaging modalities enable us to noninvasively characterize certain types of cardiomyopathies, including cardiac amyloidosis and cardiac sarcoidosis, with great confidence. We expect to improve recognition and promote the application of such advanced techniques in the imaging and management of these potentially lethal cardiomyopathies.

Reversible cardiac dysfunction in severe COVID-19 infection, mechanisms and case report.

A previously healthy 49-year-old male patient presented with COVID-19 infection and required mechanical ventilation and extracorporeal membrane oxygenation due to severe hypoxemia. Echocardiography showed cardiac dysfunction with an apical sparing strain pattern, which rapidly normalized within a week. Apical sparing myocardial strain in patients with COVID-19 infection may suggest reverse-type stress cardiomyopathy.

Comparison of echocardiographic parameters with cardiac magnetic resonance imaging in the assessment of right ventricular function.

INTRODUCTION: The right ventricle (RV) strain measured by speckle tracking (RVS) is an echocardiographic parameter used to assess RV function. We compared RVS to RV fractional area change (FAC%), tricuspid annular plane systolic excursion (TAPSE) and Doppler tissue imaging-derived peak systolic velocity (S') in the assessment of right ventricular (RV) systolic function measured using cardiac magnetic resonance imaging (MRI). METHODS: We enrolled consecutive patients who underwent cardiac MRI between Jan 2012 and Dec 2017 and a transthoracic echocardiogram (TTE) within 1 month of the MRI with no interval event. Baseline clinical characteristics and MRI parameters were extracted from chart review. Echocardiographic parameters were measured prospectively. TTE parameters including RVS, TAPSE, S', and FAC% were tested for accuracy to identify impaired RV EF (EF < 45% & <30%) using receiver operator curves. RESULTS: The study cohort included 500 patients with mean age 55 years ± 18 and peak tricuspid regurgitation velocity 2.7 ± 1.4 m/s. The area under ROC for RVS was 0.69 (95% CI 0.63-0.75) and 0.78 (95% CI 0.70-0.88) to predict RVEF < 45% & RVEF < 30%, respectively. The RV FAC% had second highest accuracy of predicting RVEF among all the TTE parameters tested in study. CONCLUSION: Right ventricular strain is the most accurate echocardiographic method to detect impaired right ventricular systolic function when using MRI as the gold standard.

First-pass myocardial perfusion MRI with reduced subendocardial dark-rim artifact using optimized Cartesian sampling.

PURPOSE: The presence of subendocardial dark-rim artifact (DRA) remains an ongoing challenge in first-pass perfusion (FPP) cardiac magnetic resonance imaging (MRI). We propose a free-breathing FPP imaging scheme with Cartesian sampling that is optimized to minimize the DRA and readily enables near-instantaneous image reconstruction. MATERIALS AND METHODS: The proposed FPP method suppresses Gibbs ringing effects-a major underlying factor for the DRA-by "shaping" the underlying point spread function through a two-step process: 1) an undersampled Cartesian sampling scheme that widens the k-space coverage compared to the conventional scheme; and 2) a modified parallel-imaging scheme that incorporates optimized apodization (k-space data filtering) to suppress Gibbs-ringing effects. Healthy volunteer studies (n = 10) were performed to compare the proposed method against the conventional Cartesian technique-both using a saturation-recovery gradient-echo sequence at 3T. Furthermore, FPP imaging studies using the proposed method were performed in infarcted canines (n = 3), and in two symptomatic patients with suspected coronary microvascular dysfunction for assessment of myocardial hypoperfusion. RESULTS: Width of the DRA and the number of DRA-affected myocardial segments were significantly reduced in the proposed method compared to the conventional approach (width: 1.3 vs. 2.9 mm, P < 0.001; number of segments: 2.6 vs. 8.7; P < 0.0001). The number of slices with severe DRA was markedly lower for the proposed method (by 10-fold). The reader-assigned image quality scores were similar (P = 0.2), although the quantified myocardial signal-to-noise ratio was lower for the proposed method (P < 0.05). Animal studies showed that the proposed method can detect subendocardial perfusion defects and patient results were consistent with the gold-standard invasive test. CONCLUSION: The proposed free-breathing Cartesian FPP imaging method significantly reduces the prevalence of severe DRAs compared to the conventional approach while maintaining similar resolution and image quality. LEVEL OF EVIDENCE: 2 J. Magn. Reson. Imaging 2017;45:542-555.

Optimal boundary detection method and window settings for coronary atherosclerotic plaque volume analysis in coronary computed tomography angiography: comparison with intravascular ultrasound.

OBJECTIVE: To evaluate optimal methodology for quantitative plaque volume analysis by coronary CT angiography (QCT). METHODS: Fifty-one coronary artery segments were evaluated and contour measurements based on two different methods [(1) no gap, or (2) fixed 0.3-mm gap between inner and outer boundary] were compared with intravascular ultrasound (IVUS). In addition, three different window width (WW) and level (WL) settings [fixed (740/220) Hounsfield unit (HU), adjusted (155 % and 65 % of mean luminal intensity of the segment, and aorta adjusted (155 % and 65 % of mean luminal intensity of central aorta)] were used for semiautomated plaque volume analysis. RESULTS: For boundary detection, the no gap method led to underestimation compared with IVUS (105.4 ± 82.3 vs. 136.1 ± 72.8 mm(3), p < 0.001), while fixed 0.3-mm gap showed no difference between IVUS and QCT (136.1 ± 72.8 vs. 139.8 ± 93.9 mm(3), p = 0.50). Comparison of the three different window settings demonstrated that the aorta adjusted setting underestimated (120.5 ± 74.3 vs. 136.1 ± 72.8 mm(3), p = 0.003), while fixed setting showed the least mean difference compared with IVUS (3.8 ± 39.8 mm(3), p = 0.50). CONCLUSION: For plaque volumetric assessment, optimal results were obtained with fixed 0.3-mm gap with fixed HU setting (740/220). KEY POINTS: • Quantitative plaque volume analysis by coronary CT angiography has recently emerged. • Different boundary detection methods and window width and level settings were evaluated. • Fixed 0.3-mm gap with fixed HU setting (740/220) afforded optimal results.

Predictors of high-risk coronary artery disease in subjects with normal SPECT myocardial perfusion imaging.

BACKGROUND: While uncommon, normal stress SPECT myocardial perfusion imaging (MPI) can be seen in patients with high-risk coronary artery disease (CAD) by invasive coronary angiography (ICA).The predictors of high-risk CAD in patients with normal SPECT-MPI have not been described. METHODS: We studied 580 patients (age 64 ± 12 years, 49% men) without known CAD who underwent stress-gated SPECT-MPI [exercise (41%) or vasodilator (59%)] <2 months before ICA and had summed stress score (SSS) <4. High-risk CAD was defined as 3 vessels with ≥70% stenosis, 2 vessels with ≥70% stenosis including proximal left anterior descending, or left main with ≥50% stenosis. Obstructive non-high-risk CAD was defined by the presence of a ≥70% stenosis but without having other high-risk criteria. Tenfold cross-validated receiver operating characteristic (ROC) estimates were obtained to assess the predictors of high-risk CAD. RESULTS: Forty-two subjects (7.2%) had high-risk CAD and 168 (29.0%) had obstructive non-high-risk CAD. Variables associated with high-risk CAD were pretest probability of CAD ≥66% (Odds ratio [OR] 3.63, 95% CI 1.6-8.3, P = .002), SSS > 0 (OR 7.46, 95% CI 2.6-21.1, P < 0.001), and abnormal TID (OR 2.16, 95% CI 1.0-4.5, P = 0.044). When substituted for TID, EF change was also predictive of high-risk CAD (OR 0.93, 95% CI 0.9-1.0, P = 0.023). The prevalence of high-risk CAD increased as the number of these predictors increased. In a sub-analysis of patients in whom quantitative total perfusion deficit (TPD) was available, TPD > 0 was also a predictor of high-risk CAD (OR 6.01, 95% CI 1.5-22.2, P = 0.011). CONCLUSION: Several clinical, stress, and SPECT-MPI findings are associated high-risk CAD among patients with normal SPECT-MPI. Consideration of these factors may improve the overall assessment of the likelihood of high-risk CAD in patients undergoing stress SPECT-MPI.

All-systolic non-ECG-gated myocardial perfusion MRI: Feasibility of multi-slice continuous first-pass imaging.

PURPOSE: To develop and test the feasibility of a new method for non-ECG-gated first-pass perfusion (FPP) cardiac MR capable of imaging multiple short-axis slices at the same systolic cardiac phase. METHODS: A magnetization-driven pulse sequence was developed for non-ECG-gated FPP imaging without saturation-recovery preparation using continuous slice-interleaved radial sampling. The image reconstruction method, dubbed TRACE, used self-gating based on reconstruction of a real-time image-based navigator combined with reference-constrained compressed sensing. Data from ischemic animal studies (n = 5) was used in a simulation framework to evaluate temporal fidelity. Healthy subjects (n = 5) were studied using both the proposed approach and the conventional method to compare the myocardial contrast-to-noise ratio (CNR). Patients (n = 2) underwent adenosine stress studies using the proposed method. RESULTS: Temporal fidelity of the developed method was shown to be sufficient at high heart-rates. The healthy volunteers studies demonstrated normal perfusion and no dark-rim artifacts. Compared with the conventional scheme, myocardial CNR for the proposed method was slightly higher (8.6 ± 0.6 versus 8.0 ± 0.7). Patient studies showed stress-induced perfusion defects consistent with invasive angiography. CONCLUSION: The presented methods and results demonstrate feasibility of the proposed approach for high-resolution non-ECG-gated FPP imaging of 3 myocardial slices at the same systolic phase, and indicate its potential for achieving desirable image quality (high CNR and no dark-rim artifacts).

Accelerated whole-heart coronary MRA using motion-corrected sensitivity encoding with three-dimensional projection reconstruction.

PURPOSE: To achieve whole-heart coronary magnetic resonance angiography (MRA) with (1.0 mm)(3) spatial resolution and 5 min of free-breathing scan time. METHODS: We used an electrocardiograph-gated, T2-prepared and fat-saturated balanced steady state free precession sequence with 3DPR trajectory for free-breathing data acquisition with 100% gating efficiency. For image reconstruction, we used a self-calibrating iterative SENSE scheme with integrated retrospective motion correction. We performed healthy volunteer study to compare the proposed method with motion-corrected gridding at different retrospective undersampling levels on apparent signal-to-noise ratio (aSNR) and subjective coronary artery (CA) visualization scores. RESULTS: Compared with gridding, the proposed method significantly improved both image quality metrics for undersampled datasets with 6000, 8000, and 10,000 projections. With as few as 10,000 projections, the proposed method yielded good CA visualization scores (3.02 of 4) and aSNR values comparable to those with 20,000 projections. CONCLUSION: Using the proposed method, good image quality was observed for free breathing whole-heart coronary MRA at (1.0 mm)(3) resolution with an achievable scan time of 5 min.

Clinical Feasibility of 3D Automated Coronary Atherosclerotic Plaque Quantification Algorithm on Coronary Computed Tomography Angiography: Comparison with Intravascular Ultrasound.

OBJECTIVE: To evaluate the diagnostic performance of automated coronary atherosclerotic plaque quantification (QCT) by different users (expert/non-expert/automatic). METHODS: One hundred fifty coronary artery segments from 142 patients who underwent coronary computed tomography angiography (CCTA) and intravascular ultrasound (IVUS) were analyzed. Minimal lumen area (MLA), maximal lumen area stenosis percentage (%AS), mean plaque burden percentage (%PB), and plaque volume were measured semi-automatically by expert, non-expert, and fully automatic QCT analyses, and then compared to IVUS. RESULTS: Between IVUS and expert QCT analysis, the correlation coefficients (r) for the MLA, %AS, %PB, and plaque volume were excellent: 0.89 (p < 0.001), 0.84 (p < 0.001), 0.91 (p < 0.001), and 0.94 (p < 0.001), respectively. There were no significant differences in the mean parameters (all p values >0.05) except %AS (p = 0.01). The automatic QCT analysis showed comparable performance to non-expert QCT analysis, showing correlation coefficients (r) of the MLA (0.80 vs. 0.82), %AS (0.82 vs. 0.80), %PB (0.84 vs. 0.73), and plaque volume (0.84 vs. 0.79) when they were compared to IVUS, respectively. CONCLUSION: Fully automatic QCT analysis showed clinical utility compared with IVUS, as well as a compelling performance when compared with semiautomatic analyses. KEY POINTS: • Coronary CTA enables the assessment of coronary atherosclerotic plaque. • High-risk plaque characteristics and overall plaque burden can predict future cardiac events. • Coronary atherosclerotic plaque quantification is currently unfeasible in practice. • Quantitative computed tomography coronary plaque analysis software (QCT) enables feasible plaque quantification. • Fully automatic QCT analysis shows excellent performance.

Prediction of revascularization after myocardial perfusion SPECT by machine learning in a large population.

OBJECTIVE: We aimed to investigate if early revascularization in patients with suspected coronary artery disease can be effectively predicted by integrating clinical data and quantitative image features derived from perfusion SPECT (MPS) by machine learning (ML) approach. METHODS: 713 rest (201)Thallium/stress (99m)Technetium MPS studies with correlating invasive angiography with 372 revascularization events (275 PCI/97 CABG) within 90 days after MPS (91% within 30 days) were considered. Transient ischemic dilation, stress combined supine/prone total perfusion deficit (TPD), supine rest and stress TPD, exercise ejection fraction, and end-systolic volume, along with clinical parameters including patient gender, history of hypertension and diabetes mellitus, ST-depression on baseline ECG, ECG and clinical response during stress, and post-ECG probability by boosted ensemble ML algorithm (LogitBoost) to predict revascularization events. These features were selected using an automated feature selection algorithm from all available clinical and quantitative data (33 parameters). Tenfold cross-validation was utilized to train and test the prediction model. The prediction of revascularization by ML algorithm was compared to standalone measures of perfusion and visual analysis by two experienced readers utilizing all imaging, quantitative, and clinical data. RESULTS: The sensitivity of machine learning (ML) (73.6% ± 4.3%) for prediction of revascularization was similar to one reader (73.9% ± 4.6%) and standalone measures of perfusion (75.5% ± 4.5%). The specificity of ML (74.7% ± 4.2%) was also better than both expert readers (67.2% ± 4.9% and 66.0% ± 5.0%, P < .05), but was similar to ischemic TPD (68.3% ± 4.9%, P < .05). The receiver operator characteristics areas under curve for ML (0.81 ± 0.02) was similar to reader 1 (0.81 ± 0.02) but superior to reader 2 (0.72 ± 0.02, P < .01) and standalone measure of perfusion (0.77 ± 0.02, P < .01). CONCLUSION: ML approach is comparable or better than experienced readers in prediction of the early revascularization after MPS, and is significantly better than standalone measures of perfusion derived from MPS.

Significant Reduction in Mitral Regurgitation Volume Is the Main Contributor for Increase in Systolic Forward Flow in Patients with Functional Mitral Regurgitation after Transcatheter Aortic Valve Replacement: Hemodynamic Analysis Using Echocardiography.

BACKGROUND: Reduction in mitral regurgitation (MR) after transcatheter aortic valve replacement (TAVR) has previously been reported. However, the hemodynamic effects of TAVR in patients with MR have not been previously evaluated. METHODS: We analyzed 571 patients who underwent TAVR from December 2010 to December 2013. We studied 20 patients with moderate or severe preprocedural functional mitral regurgitation (FMR) who also had a follow-up transthoracic echocardiography (TTE) examination between 90 and 360 days (median 213 days) after TAVR (Significant FMR Group). We also studied age- and gender-matched 20 patients with mild or lesser MR (Nonsignificant MR Group). Left ventricular functional measurements were assessed using echocardiography before and after TAVR. Left ventricular outflow tract stroke volume measurements using pulsed-wave Doppler (SVLVOT ) were calculated as a representative of systolic forward flow, and stroke volume by the Simpson's method (SVSimpson ) was calculated as a parameter of degree of LV contraction. RESULTS: MR grade improved in 22 of 40 patients after TAVR. In both groups, BNP level decreased, left ventricular ejection fraction increased, and SVLVOT increased after TAVR. SVSimpson increased in the Nonsignificant MR Group and remained unchanged in the Significant FMR Group. Vena contracta width of MR (MRVC) decreased in the Significant FMR Group. Using multivariable analysis in the Significant FMR Group, the increase in SVLVOT significantly correlated with the decrease in MRVC (P < 0.05). CONCLUSIONS: SVLVOT increased significantly after TAVR in patients with FMR. In these patients, increase in SVLVOT after TAVR was associated with decrease in severity of MR.

Left ventricular function and volume with coronary CT angiography improves risk stratification and identification of patients at risk for incident mortality: results from 7758 patients in the prospective multinational CONFIRM observational cohort study.

PURPOSE: To assess whether gradations of left ventricular (LV) ejection fraction (LVEF) and volumes measured with coronary computed tomography (CT) would augment risk stratification and discrimination for incident mortality. MATERIALS AND METHODS: This study was approved by the institutional review board, and informed consent was obtained when required. Subjects without known coronary artery disease (CAD) who underwent cardiac CT angiography with quantitative LV measurements were categorized according to LVEF (≥ 55%, 45%-54.9%, 35%-44.9%, or <35%). LV end-systolic volume (LVESV) and LV end-diastolic volume (LVEDV) were classified as normal (≥ 90 mL) or abnormal (≥ 200 mL). CAD extent and severity was categorized as none, nonobstructive, obstructive (≥ 50%), one-vessel, two-vessel, and three-vessel or left main disease. LVEF and volumes were assessed for risk prediction and discrimination of future mortality by using Cox hazards model and receiver operating characteristic curve analysis, respectively. RESULTS: During a follow-up of 2.0 years ± 0.9, 7758 patients (mean age, 58.5 years ± 13.0; 4220 male patients [54.4%]) were studied. At multivariable analysis, worsening LVEF was independently associated with mortality for moderately (hazard ratio = 3.14, P < .001) and severely (hazard ratio = 5.19, P < .001) abnormal ejection fraction. LVEF demonstrated improved discrimination for mortality (Az = 0.816) when compared with CAD risk factors alone (Az = 0.781) or CAD risk factors plus extent and severity. At multivariable analysis of a subgroup of 3706 individuals, abnormal LVEDV (hazard ratio = 4.02) and LVESV (hazard ratio = 6.46) helped predict mortality (P < .001). Similarly, LVESV and LVEDV demonstrated improved discrimination when compared with CAD risk factors or CAD extent and severity (P < .05). CONCLUSION: LV dysfunction and volumes measured with cardiac CT angiography augment risk prediction and discrimination for future mortality.

ECG and navigator-free four-dimensional whole-heart coronary MRA for simultaneous visualization of cardiac anatomy and function.

PURPOSE: To develop a cardiac and respiratory self-gated four-dimensional (4D) coronary MRA technique for simultaneous cardiac anatomy and function visualization. METHODS: A contrast-enhanced, ungated spoiled gradient echo sequence with self-gating (SG) and 3DPR trajectory was used for image acquisition. Data were retrospectively binned into different cardiac and respiratory phases based on information extracted from SG projections using principal component analysis. Each cardiac phase was reconstructed using a respiratory motion-corrected self-calibrating SENSE framework, and those belong to the quiescent period were retrospectively combined for coronary visualization. Healthy volunteer studies were conducted to evaluate the efficacy of the SG method, the accuracy of the left ventricle (LV) function parameters and the quality of coronary artery visualization. RESULTS: SG performed reliably for all subjects including one with poor electrocardiogram (ECG). The LV function parameters showed excellent agreement with those from a conventional cine protocol. For coronary imaging, the proposed method yielded comparable apparent signal to noise ratio and coronary sharpness and lower apparent contrast to noise ratio on three subjects compared with an ECG and navigator-gated Cartesian protocol and an ECG-gated, respiratory motion-corrected 3DPR protocol. CONCLUSION: A fully self-gated 4D whole-heart imaging technique was developed, potentially allowing cardiac anatomy and function assessment from a single measurement.

Non-ECG-gated myocardial perfusion MRI using continuous magnetization-driven radial sampling.

PURPOSE: Establishing a high-resolution non-ECG-gated first-pass perfusion (FPP) cardiac MRI technique may improve accessibility and diagnostic capability of FPP imaging. We propose a non-ECG-gated FPP imaging technique using continuous magnetization-driven golden-angle radial acquisition. The main purpose of this preliminary study is to evaluate whether, in the simple case of single-slice two-dimensional imaging, adequate myocardial contrast can be obtained for accurate visualization of hypoperfused territories in the setting of myocardial ischemia. METHODS: A T1-weighted pulse sequence with continuous golden-angle radial sampling was developed for non-ECG-gated FPP imaging. A sliding-window scheme with no temporal acceleration was used to reconstruct 8 frames/s. Canines were imaged at 3T with and without coronary stenosis using the proposed scheme and a conventional magnetization-prepared ECG-gated FPP method. RESULTS: Our studies showed that the proposed non-ECG-gated method is capable of generating high-resolution (1.7 × 1.7 × 6 mm(3) ) artifact-free FPP images of a single slice at high heart rates (92 ± 21 beats/min), while matching the performance of conventional FPP imaging in terms of hypoperfused-to-normal myocardial contrast-to-noise ratio (proposed: 5.18 ± 0.70, conventional: 4.88 ± 0.43). Furthermore, the detected perfusion defect areas were consistent with the conventional FPP images. CONCLUSION: Non-ECG-gated FPP imaging using optimized continuous golden-angle radial acquisition achieves desirable image quality (i.e., adequate myocardial contrast, high spatial resolution, and minimal artifacts) in the setting of ischemia.

Towards elimination of the dark-rim artifact in first-pass myocardial perfusion MRI: removing Gibbs ringing effects using optimized radial imaging.

PURPOSE: Subendocardial dark-rim artifacts (DRAs) remain a major concern in first-pass perfusion (FPP) myocardial MRI and may lower the diagnostic accuracy for detection of ischemia. A major source of DRAs is the "Gibbs ringing" effect. We propose an optimized radial acquisition strategy aimed at eliminating ringing-induced DRAs in FPP. THEORY AND METHODS: By studying the underlying point spread function (PSF), we show that optimized radial sampling with a simple reconstruction method can eliminate the oscillations in the PSF that cause ringing artifacts. We conducted realistic MRI phantom experiments and in vivo studies (n = 12 healthy humans) to evaluate the artifact behavior of the proposed imaging scheme in comparison to a conventional Cartesian imaging protocol. RESULTS: Simulations and phantom experiments verified our theoretical expectations. The in vivo studies showed that optimized radial imaging is capable of significantly reducing DRAs in the early myocardial enhancement phase (during which the ringing effect is most prominent and may obscure perfusion defects) while providing similar resolution and image quality compared with conventional Cartesian imaging. CONCLUSION: The developed technical framework and results demonstrate that, in comparison to conventional Cartesian techniques, optimized radial imaging with the proposed optimizations significantly reduces the prevalence and spatial extent of DRAs in FPP imaging.

Two-position supine/prone myocardial perfusion SPECT (MPS) imaging improves visual inter-observer correlation and agreement.

OBJECTIVES: We aimed to compare the inter-observer agreement between two experienced readers using supine vs combined supine/prone myocardial perfusion SPECT (MPS) in a large population. METHODS: 1,181 consecutive patients without known coronary artery disease (CAD) undergoing rest (201)Tl/stress (99m)Tc-sestamibi MPS studies were evaluated. Visual reads were performed in two consecutive steps, with readers scoring the stress supine perfusion images during step 1 and rescoring the images using both supine/prone data during step 2. Visual summed stress scores (SSS) of two readers including regional scores in different vascular territories were compared. RESULTS: The specificity for both readers improved using combined supine/prone imaging (reader 1: 92% vs 86% [P = .0002], reader 2: 88% vs 72% [P < .0001]). The inter-observer correlation for SSS (0.90 vs 0.84, P < .0001) and inter-observer agreement for combined supine/prone reading (bias = 1.0, 95% confidence interval (CI) 0.9-1.2 vs bias = 3.1, 95% CI 2.8-3.4, P < .0001) were significantly better as compared to supine-only reading. The overall correlation between SSS scores for two readers improved with supine/prone imaging for both genders, as well as in the left anterior descending and right coronary territories. CONCLUSION: The inter-observer correlation and agreement significantly improve using two-position supine/prone vs supine-only imaging.

Impact of hypertriglyceridaemia on cardiovascular mortality according to low-density lipoprotein cholesterol in a 15.6-million population.

AIMS: The aim of this study was to assess the association between triglyceride (TG) levels and cardiovascular disease (CVD) mortality concerning low-density lipoprotein cholesterol (LDL-C) and age in the general population. METHODS AND RESULTS: From the Korean National Health Insurance Service database, 15 672 028 participants aged 18-99 who underwent routine health examinations were followed up for CVD mortality. Hazard ratios for CVD mortality were calculated using Cox models after adjusting for various confounders. During a mean of 8.8 years of follow-up, 105 174 individuals died of CVD. There was a clear log-linear association between TG and overall CVD mortality down to 50 mg/dL. Each two-fold increase in TG was associated with 1.10-fold (overall CVD), 1.22-fold [ischaemic heart disease (IHD)], 1.24-fold [acute myocardial infarction (AMI)], and 1.10-fold (ischaemic stroke) higher CVD mortality. Haemorrhagic stroke and heart failure were not associated with TG levels. The impact of hypertriglyceridaemia (HTG) on CVD weakened but remained present in persons with LDL-C < 100 mg/dL, in whom each two-fold higher TG was associated with 1.05-fold (overall CVD), 1.12-fold (IHD), 1.15-fold (AMI), and 1.05-fold (ischaemic stroke) higher CVD mortality. The younger population (18-44 years) had stronger associations between TG levels and mortality from overall CVD, IHD, and AMI than the older population. CONCLUSION: Hypertriglyceridaemia independently raises CVD mortality with lingering risks in young and older individuals with low LDL-C levels, suggesting the importance of management of HTG even with controlled LDL-C.

This prospective study evaluated the association between triglyceride (TG) levels and cardiovascular disease (CVD) mortality in the general population, particularly in individuals with well-controlled low-density lipoprotein cholesterol (LDL-C) levels. The TG levels log-linearly increased the mortality from CVD, especially ischaemic heart disease and ischaemic stroke, down to at least 50 mg/dL (0.56 mmol/L), as residual CVD risks associated with high TG were apparent in individuals, even with LDL-C < 100 mg/dL (2.59 mmol/L). Maintaining TG levels below 100 mg/dL may be beneficial even in seemingly low-risk groups, such as young people with normal or optimal LDL-C levels.