Stress Perfusion Cardiac Magnetic Resonance Research Articles

Feasibility and prognostic value of vasodilator stress perfusion CMR in elderly patients > 75 years without known CAD

The World's ageing population raises the question of the benefit of screening for coronary artery disease (CAD) in very old patients. To assess the prognostic value of vasodilator stress perfusion cardiac magnetic resonance (CMR) in elderly patients aged > 75 years without previous known CAD. Consecutive elderly patients > 75 years without known CAD referred for vasodilator stress perfusion CMR were followed for major adverse cardiovascular events (MACE) defined as cardiac death, non-fatal myocardial infarction or stroke. Univariable and multivariable Cox regressions for MACE were performed to determine the prognostic association of inducible ischemia or late gadolinium enhancement (LGE) by CMR beyond traditional clinical risk indexes. Of 754 elderly high risk patients (82 ± 4 years, 48.4% men), 747 (99%) completed the CMR protocol, and among those 659 (88.2%) completed the follow-up (median follow-up 5.7 ± 2.5 years). Patients without inducible ischemia or LGE experienced a substantially lower annual rate of MACE (5.5% vs. 9.9% for those with ischemia and vs. 6.9% for those with ischemia and/or LGE). In a multivariable stepwise Cox regression including clinical characteristics and CMR indexes, the absence of inducible ischemia was an independent predictor of a lower incidence of MACE at follow-up (hazard ratio 0.46; 95% confidence interval: 0.34 to 0.62; P < 0.001) ( Fig. 1 ) and all-cause mortality (hazard ratio 0.67; 95% confidence interval: 0.45 to 0.97; P = 0.037). Using Kaplan-Meier analyses, the presence of myocardial ischemia identified the occurrence of future CV events ( P < 0.001). Stress CMR is safe and has discriminative prognostic value in very elderly patients without known CAD, with a very low negative event rate in patients without ischemia or infarction, and with a higher rate of future CV event or death in patients with ischemia. Kaplan Meier curves ( Fig. 1 )

Vasodilator stress perfusion CMR is feasible and has prognostic value in morbid obese patients without known CAD

Obesity is a growing public health problem with an impact on cardiovascular disease. But current methods for the detection of myocardial ischemia remain limited in obese patients and stress cardiac magnetic resonance (CMR) may be a powerful alternative. To determine feasibility and prognostic value of vasodilator stress perfusion CMR in morbid obese patients with body mass index (BMI) ≥ 40 kg/m 2 . Consecutive patients with a BMI > 40 kg/m 2 and without known coronary artery disease (CAD) referred for vasodilating stress CMR were followed for major adverse cardiovascular events MACE, defined as cardiac death, non-fatal myocardial infarction of stroke. Univariable and multivariable Cox regressions for MACE were performed to determine the prognostic association of inductible ischemia or late gadolinium enhancement (LGE) by CMR. Of 452 obese patients (mean BMI 43.9 ± 3.8 kg/m 2 , 44% of men), 444 (98%) completed the CMR protocol and among those, 404 (91%) completed the follow-up (mean 5.6 ± 2.2 years). Patients without inductible ischemia or LGE experienced a susbtantially lower annual rate of MACE (3.3% vs. 12.4% for those with ischemia and vs. 11,2% for those with ischemia and LGE). In a multivariable stepwise Cox regression including clinical characteristics and CMR indexes, the absence of inducible ischemia was an independent predictor of a lower incidence of MACE at follow-up (Hazard ratio 0.20, 95% confidence interval: 0.11 to 0.36; P < 0.001) ( Fig. 1 ) and cardiac death (hazard ratio 0.11 95% confidence interval: 0.02 to 0.63). Using Kaplan-Meier analyses, myocardial ischemia identified future CV events/survival ( P < 0.001). Stress CMR is feasible and has a high prognostic value in morbid obese patients, with a very low negative event rate in patients without ischemia or infarction as opposed to patients with inducible ischemia and/or presence of myocardial infarct. Kaplan-Meier curves ( Fig. 1 ).

The use of adenosine stress perfusion cardiac magnetic resonance in determining incomplete revascularization post-coronary artery bypass grafting and the importance of anterior septal vessels.

The use of adenosine stress perfusion cardiac magnetic resonance in determining incomplete revascularization post-coronary artery bypass grafting and the importance of anterior septal vessels.

Prognostic Implications of Blunted Feature-Tracking Global Longitudinal Strain During Vasodilator Cardiovascular Magnetic Resonance Stress Imaging

ObjectivesThe purpose of this study was to determine the prognostic value of feature-tracking global longitudinal strain (GLS) measured during vasodilator stress cardiac magnetic resonance (CMR) imaging. BackgroundPrior studies have suggested that blunted myocardial strain during dobutamine stress echocardiography may be associated with adverse prognosis. Recent developments in CMR feature-tracking techniques now allow assessment of strain in clinical practice using standard cine images without specialized pulse sequences or complex post-processing. Whether feature-tracking GLS measured during vasodilator stress provides independent and incremental prognostic data is unclear. MethodsConsecutive patients undergoing stress perfusion CMR were prospectively enrolled (n = 535). Feature-tracking stress GLS was measured immediately after regadenoson perfusion. Patients were followed for major adverse cardiac events (MACE): death, nonfatal myocardial infarction, heart failure hospitalization, sustained ventricular tachycardia, and late revascularization. Cox proportional hazards regression modeling was used to examine the association between stress GLS and MACE. The incremental prognostic value of stress GLS was assessed in nested models. ResultsOver a median follow-up of 1.5 years, 82 patients experienced MACE. By Kaplan-Meier analysis, patients with stress GLS ≥ median (–19%) had significantly reduced event-free survival compared with those with stress GLS < median (log-rank p < 0.001). Stress GLS was significantly associated with risk of MACE after adjustment for clinical and imaging risk factors including ischemia, ejection fraction, and late gadolinium enhancement (hazard ratio: 1.267; p < 0.001). Addition of stress GLS into a model with clinical and imaging predictors resulted in significant increase in the C-index (from 0.80 to 0.85; p = 0.031) and a continuous net reclassification improvement of 0.898 (95% confidence interval: 0.565 to 1.124). ConclusionsFeature-tracking stress GLS measured during vasodilator stress CMR is an independent predictor of MACE in patients with known or suspected coronary artery disease, incremental to common clinical and imaging risk factors. These findings suggest a role for feature-tracking derived stress GLS in identifying patients at highest risk of adverse events following stress CMR.

Global Coronary Flow Reserve Measured During Stress Cardiac Magnetic Resonance Imaging Is an Independent Predictor of Adverse Cardiovascular Events

ObjectivesThe aim of this study was to evaluate the incremental prognostic value of global coronary flow reserve (CFR) in patients with known or suspected coronary artery disease who were undergoing stress cardiac magnetic resonance (CMR) imaging. BackgroundCoronary microvascular dysfunction results in impaired global CFR and is implicated in the development of both atherosclerosis and heart failure. Although noninvasive assessment of CFR with positron emission tomography provides independent prognostic information, the incremental prognostic value of CMR-derived CFR remains unclear. MethodsConsecutive patients undergoing stress perfusion CMR were prospectively enrolled (n = 507). Coronary sinus flow was measured using phase-contrast imaging at baseline (pre) and immediately after stress (peak) perfusion. CFR was calculated as the ratio of peak to pre-flow. Patients were followed for major adverse cardiac events (MACE): death, nonfatal myocardial infarction, heart failure hospitalization, sustained ventricular tachycardia, and late revascularization. Cox proportional hazards regression modeling was used to examine the association between CFR and MACE. The incremental prognostic value of CFR was assessed in nested models. ResultsOver a median follow-up of 2.1 years, 80 patients experienced MACE. By Kaplan-Meier analysis, the risk of MACE was significantly higher in patients with CFR lower than the median (2.2) (log-rank p < 0.001); this remained significant after adjustment for the presence of ischemia and late gadolinium enhancement (LGE) (log-rank p < 0.001). CFR was significantly associated with the risk of MACE after adjustment for clinical and imaging risk factors, including ischemia extent, ejection fraction, and LGE size (hazard ratio: 1.238; p = 0.018). Addition of CFR in this model resulted in significant improvement in the C-index (from 0.70 to 0.75; p = 0.0087) and a continuous net reclassification improvement of 0.198 (95% confidence interval: 0.120 to 0.288). ConclusionsCMR-derived CFR is an independent predictor of MACE in patients with known or suspected coronary artery disease, incremental to common clinical and CMR risk factors. These findings suggest a role for CMR-derived CFR in identifying patients at risk of adverse events following stress CMR, even in the absence of ischemia and LGE.

Correlation of FFR-derived from CT and stress perfusion CMR with invasive FFR in intermediate-grade coronary artery stenosis

Only one-third of intermediate-grade coronary artery stenosis (i.e. 40-70% diameter narrowing) causes myocardial ischemia, requiring most often additional invasive work-up with invasive fractional flow reserve (FFR). To evaluate the correlations between FFR estimates derived from computed tomography (FFRCT) and adenosine perfusion cardiac magnetic resonance (CMR) with invasive FFR in intermediate-grade stenosis. Thirty-seven patients (mean age 61 ± 9 years; 25 men) who underwent adenosine perfusion CMR, quantitative coronary angiography and FFR in the work-up for intermediate-grade stenoses (n = 39) diagnosed at coronary CT angiography were retrospectively evaluated. Blinded FFRCT analysis was computed on each intermediate-grade lesion and correlated to the FFR values. On adenosine CMR, subendocardial time-enhancement maximal upslopes, normalized by respective left ventricle cavity upslopes, were obtained distal to a coronary stenosis (RISK area) and in remote myocardium (REMOTE area). The perfusion was subsequently assessed without (uncorrected RISK) and after correction for remote perfusion (relative myocardial perfusion index = REMOTE/RISK ratio), and then correlated to the FFR values. Differences in correlations were tested with z statistics and considered statistically significant different at a p < 0.05 level. The average FFR value was 0.85 ± 0.10 (0.60-0.98 range), 28% (n = 11) was ≤ 0.80. FFR value correlated poorly with uncorrected RISK upslopes (r = 0.151; p = 0.36), but equally strongly with FFRCT (r = 0.675; p < 0.001) and the relative myocardial perfusion index (r = - 0.63) (p < 0.001; z = 6.72) for assessment of lesion-specific ischemia. Both FFRCT and adenosine perfusion CMR strongly correlate with invasive FFR measurements for intermediate-grade stenosis. These preliminary findings pave the way for further studies evaluating non-invasively intermediate coronary stenosis in clinical practice.

Coronary artery disease in post-menopausal women: are there appropriate means of assessment?

The recognition of sex differences in cardiovascular disease, particularly the manifestations of coronary artery disease (CAD) in post-menopausal women, has introduced new challenges in not only understanding disease mechanisms but also identifying appropriate clinical means of assessing the efficacy of management strategies. For example, the majority of treatment algorithms for CAD are derived from the study of males, focus on epicardial stenoses, and inadequately account for the small intramyocardial vessel disease in women. However, newer investigational modalities, including stress perfusion cardiac magnetic resonance imaging and positron emission tomography are providing enhanced diagnostic accuracy and prognostication for women with microvascular disease. Moreover, these investigations may soon be complemented by simpler screening tools such as retinal vasculature imaging, as well as novel biomarkers (e.g. heat shock protein 27). Hence, it is vital that robust, sex-specific cardiovascular imaging modalities and biomarkers continue to be developed and are incorporated into practice guidelines that are used to manage women with CAD, as well as gauge the efficacy of any new treatment modalities. This review provides an overview of some of the sex differences in CAD and highlights emerging advances in the investigation of CAD in post-menopausal women.

Stress perfusion Cardiac Magnetic Resonance in Patients with Antiphospholipid Syndrome.

Background:Antiphospholipid syndrome (APS) is characterized by the combination of recurrent arterial and venous thrombotic events and detection of persistently elevated antiphospholipid antibody titers in the serum or plasma. APS clinical manifestations also include non-thrombotic complications from various organ systems, mainly the CNS, kidneys, and heart. Cardiac manifestations of APS include valvulopathy, myocardial infarction and angina (stable, unstable, and Pritzmental angina). A previously published case series of cardiac magnetic resonance (CMR) in patients with APS has revealed a high rate of asymptomatic myocardial necrosis and scarring, but the prevalence of myocardial ischemia identified as CMR perfusion defects prior to development of necrosis is unknown.Aims of the study:To detect CMR imaging markers of myocardial ischemia in APS patients without symptoms of cardiovascular disease (CVD).Methods:We will scan fifty APS patients without symptoms of CVD stress-perfusion CMR in a 1.5 Tesla tomographer, after intravenous infusion of adenosine and gadolinium. In addition to markers of cardiac anatomy and function, we will record imaging markers of ischemia and scarring, namely perfusion defects (PDs), and late gadolinium enhancement (LGE). We will perform parametrics using dedicated software in order to derive each patient’s myocardial perfusion reserve index (MPRI). Scans will be reviewed independently by two experienced reviewers, with evaluation of inter- and intra-observer reliability. Statistical hypotheses will be examined using Student’s test and Pearson’s correlation coefficient, or non-parametric equivalents (Kruskall-Wallis and Spearman) for continuous variables, and Fisher’s exact test for binary variables. Linear or logistic regression analyses will be used to investigate APS-related determinants of subclinical myocardial ischemia.Anticipated benefits:We expect to identify CMR imaging patterns characteristic of APS, which will allow proactive therapeutic interventions for primary prevention of CVD and guide further research into the pathogenesis of APS cardiac manifestations.

Diagnostic performance of stress perfusion cardiac magnetic resonance for the detection of coronary artery disease: A systematic review and meta-analysis

IntroductionThe purpose of this study was to investigate the accuracy of qualitative stress perfusion cardiac magnetic resonance (CMR) to diagnose ischemia-causing lesions according to different definitions of significant coronary artery disease (CAD), and magnetic field strength. MethodsWe searched PubMed, Web of Science, and the Cochrane Library for studies evaluating diagnostic performance of qualitative stress perfusion CMR for diagnosis of CAD versus coronary angiography or fractional flow reserve (FFR) from inception to 10 September 2017. We used hierarchical models to synthesize the available data. ResultsSixty-seven studies (7113 patients) met the inclusion criteria. The patient-based analysis of studies using FFR as the reference standard demonstrated a mean sensitivity of 0.90 (95% confidence interval [CI], 0.85–0.93) and a mean specificity of 0.85 (95% CI, 0.80–0.89). The patient-based analyses for detecting coronary stenosis ≥50% and coronary stenosis ≥70% at 1.5T and for detecting coronary stenosis ≥50% and coronary stenosis ≥70%, at 3T, demonstrated a mean sensitivity of 0.82 (95% CI, 0.79–0.84), 0.86 (95% CI, 0.83–0.89), 0.90 (95% CI, 0.82–0.95), and 0.91 (95% CI, 0.79–0.96), respectively; with a mean specificity of 0.75 (95% CI, 0.71–0.80), 0.77 (95% CI, 0.71–0.81), 0.79 (95% CI, 0.69–0.86), and 0.74 (95% CI, 0.59–0.85). ConclusionQualitative stress perfusion CMR has high accuracy for the diagnosis of CAD, irrespective of the reference standard and the magnet strength. Studies using FFR as the reference standard had higher diagnostic accuracy on a patient level compared to studies using coronary angiography, with a notable difference in specificity.

Accurate late gadolinium enhancement prediction by early T1- based quantitative synthetic mapping

ObjectivesEarly synthetic gadolinium enhancement (ESGE) imaging from post-contrast T1 mapping after adenosine stress-perfusion cardiac magnetic resonance (CMR) was compared to conventional late gadolinium enhancement (LGE) imaging for assessing myocardial scar.MethodsTwo hundred fourteen consecutive patients suspected of myocardial ischaemia were referred for stress-perfusion CMR. Myocardial infarct volume was quantified on a per-subsegment basis in both synthetic (2–3 min post-gadolinium) and conventional (9 min post-gadolinium) images by two independent observers. Sensitivity, specificity, PPV and NPV were calculated on a per-patient and per-subsegment basis.ResultsBoth techniques detected 39 gadolinium enhancement areas in 23 patients. The median amount of scar was 2.0 (1.0–3.1) g in ESGE imaging and 2.2 (1.1–3.1) g in LGE imaging (p=0.39). Excellent correlation (r=0.997) and agreement (mean absolute difference: -0.028±0.289 ml) were found between ESGE and LGE images. Sensitivity, specificity, PPV and NPV of ESGE imaging were 96 (78.9–99.9), 99 (97.1–100.0)%, 96 (76.5–99.4) and 99.5 (96.6–99.9) in patient-based and 99 (94.5–100.0), 100 (99.9–100.0)%, 97.0 (91.3–99.0) and 100.0 (99.8–100.0) in subsegment-based analysis.ConclusionESGE based on post-contrast T1 mapping after adenosine stress-perfusion CMR imaging shows excellent agreement with conventional LGE imaging for assessing myocardial scar, and can substantially shorten clinical acquisition time.Key Points• Synthetic gadolinium enhancement images can be used for detection of myocardial scar.• Early synthetic gadolinium enhancement images can substantially shorten clinical acquisition time.• ESGE has high diagnostic accuracy as compared to conventional late gadolinium enhancement.• Quantification of myocardial scar with ESGE closely correlates with conventional LGE.• ESGE after stress perfusion CMR avoids need for additional gadolinium administration.

Stress Perfusion Coronary Flow Reserve Versus Cardiac Magnetic Resonance for Known or Suspected CAD

BackgroundPhase-contrast (PC) cine magnetic resonance imaging (MRI) of the coronary sinus is a noninvasive method to quantify coronary flow reserve (CFR). ObjectivesThis study sought to compare the prognostic value of CFR by cardiac magnetic resonance (CMR) and stress perfusion CMR to predict major adverse cardiac events (MACE). MethodsParticipants included 276 patients with known coronary artery disease (CAD) and 400 with suspected CAD. CFR was calculated as myocardial blood flow during adenosine triphosphate infusion divided by myocardial blood flow at rest using PC cine MRI of the coronary sinus. ResultsDuring a median follow-up of 2.3 years, 47 patients (7%) experienced MACE. Impaired CFR (<2.0) and >10% ischemia on stress perfusion CMR were significantly associated with MACE in patients with known CAD (hazard ratio [HR]: 5.17 and HR: 5.10, respectively) and suspected CAD (HR: 14.16 and HR: 6.50, respectively). The area under the curve for predicting MACE was 0.773 for CFR and 0.731 for stress perfusion CMR (p = 0.58) for patients with known CAD, and 0.885 for CFR and 0.776 for stress perfusion CMR (p = 0.059) in the group with suspected CAD. In patients with known CAD, sensitivity, specificity, and positive and negative predictive values to predict MACE were 64%, 91%, 38%, and 97%, respectively, for CFR, and 82%, 59%, 15%, and 97%, respectively, for stress perfusion CMR. In the suspected CAD group, these values were 65%, 99%, 80%, and 97%, respectively, for CFR, and 72%, 83%, 22%, and 98%, respectively, for stress perfusion CMR. ConclusionsThe predictive values of CFR and stress perfusion CMR for MACE were comparable in patients with known CAD. In patients with suspected CAD, CFR showed higher HRs and areas under the curve than stress perfusion CMR, suggesting that CFR assessment by PC cine MRI might provide better risk stratification for patients with suspected CAD.

Pharmacological stress, rest perfusion and delayed enhancement cardiac magnetic resonance identifies very early cardiac involvement in systemic sclerosis patients of recent onset.

To evaluate occult cardiac involvement in asymptomatic systemic sclerosis (SSc) patients by pharmacological stress, rest perfusion and delayed enhancement cardiac magnetic resonance (CMR), for a very early identification of patients at higher risk of cardiac-related mortality. Sixteen consecutive patients with definite SSc, fulfilling the American College of Rheumatology/European League Against Rheumatism 2013 classification criteria in less than 1 year from the onset of Raynaud's phenomenon, underwent pharmacological stress, rest perfusion and delayed enhancement CMR. At enrollment, no patient showed signs and/or symptoms suggestive for cardiac involvement. No patient showed traditional cardiovascular risk factors. Both the 12-lead electrocardiogram examination and echocardiographic evaluation did not show any alterations in our cohort. Stress perfusion defects of left ventricle were detected in six out of 16 (37.5%) patients and these defects did not match with the coronary flow distribution. The results showed the presence of two different patterns of stress perfusion defects: sub-endocardial and/or a midmyocardial. The presence of stress perfusion defects did not correlate with any clinical feature of enrolled patients. Myocardial stress perfusion defects may be detected early by pharmacological stress perfusion CMR, a reliable and sensitive technique for the noninvasive evaluation of SSc heart disease, in patients with SSc of recent onset. These defects seem to be independent from traditional risk factors and associated comorbidities, suggesting they are a specific hallmark of the disease.

Effects of caffeine intake prior to stress cardiac magnetic resonance perfusion imaging on regadenoson- versus adenosine-induced hyperemia as measured by T1 mapping

The antagonistic effects of caffeine on adenosine receptors are a possible cause of false-negative stress perfusion imaging. The purpose of this study was to determine the effects of coffee intake <4 h prior to stress perfusion cardiac magnetic resonance imaging (CMR) in regadenoson- versus adenosine-induced hyperemia as measured with T1-mapping. 98 consecutive patients with suspected coronary artery disease referred for either adenosine or regadenoson perfusion CMR were included in this analysis. Twenty-four patients reported coffee consumption <4 h before CMR (15 patients with adenosine, and 9 patients with regadenoson); 74 patients reported no coffee intake (50 patients with adenosine, and 24 patients with regadenoson). T1 mapping was performed using a modified look-locker inversion recovery sequence. T1 reactivity was determined by subtracting T1rest from T1stress. T1rest, T1stress, and T1 reactivity in patients referred for regadenoson perfusion CMR were not significantly different when comparing patients with <4 h coffee intake and patients who reported no coffee intake (976 ± 4 ms, 1019 ± 48 ms, and 4.4 ± 3.2% vs 971 ± 33 ms, 1023 ± 43 ms, and 5.4 ± 2.4%) (p = 0.70, 0.79, and 0.40), and similar to values in patients without coffee intake undergoing adenosine CMR. In patients with <4 h coffee intake, T1stress, and T1 reactivity were significantly lower for adenosine (898 ± 51 ms, and −7.8 ± 5.0%) compared to regadenoson perfusion CMR (p < 0.001). Coffee intake <4 h prior to regadenoson perfusion CMR has no effect on stress-induced hyperemia as measured with T1 mapping.

Stress Perfusion CMR in Patients With Known and Suspected CAD: Prognostic Value and Optimal Ischemic Threshold for Revascularization

ObjectivesThis study sought to determine the ischemia threshold and additional prognostic factors that identify patients for safe deferral from revascularizations in a large cohort of all-comer patients with known or suspected coronary artery disease (CAD). BackgroundStress-perfusion cardiac magnetic resonance (CMR) is increasingly used in daily practice for ischemia detection. However, there is insufficient evidence about the ischemia burden that identifies patients who benefit from revascularization versus those with a good prognosis who receive drugs only. MethodsAll patients with known or suspected CAD referred to stress-perfusion CMR for myocardial ischemia assessment were prospectively enrolled. The CMR examination included standard functional adenosine stress first-pass perfusion (gadobutrol 0.1 mmol/kg Gadovist, Bayer AG, Zurich, Switzerland) and late gadolinium enhancement (LGE) acquisitions. Presence of ischemia and ischemia burden (number of ischemic segments on a 16-segment model), and of scar and scar burden (number and transmurality of scar segments in a 17-segment model) were assessed. The primary endpoint was a composite of cardiac death, nonfatal myocardial infarction (MI), and late coronary revascularization (>90 days post-CMR); the secondary endpoint was a composite of cardiac death and nonfatal MI. ResultsDuring a follow-up of 2.5 ± 1.0 years, 86 and 32 of 1,024 patients (1,103 screened patients) experienced the primary and secondary endpoints, respectively. On Kaplan-Meier curves for the primary and secondary endpoints, patients without ischemia had excellent outcomes that did not differ from patients with <1.5 ischemic segments. In multivariate Cox regression analyses of the entire population and of the subgroups, ischemia burden (threshold: ≥1.5 ischemic segments) was consistently the strongest predictor of the primary and secondary endpoints with hazard ratios (HRs) of 7.42 to 8.72 (p < 0.001), whereas age (≥67 years), left ventricular ejection fraction (≤40%), and scar burden (LGE score ≥0.03) contributed significantly, but to a lesser extent, in all models with HRs of 2.01 to 3.48, 1.75 to 1.96, and 1.66 to 1.76, respectively. ConclusionsIn a large all-comer patient cohort with known and suspected CAD, an ischemia burden of ≥1.5 ischemic segments on stress-perfusion CMR was the strongest predictor of the primary and secondary endpoints. Patients with zero or 1 ischemic segment can be safely deferred from revascularizations.

Diagnostic Performance of Coronary CT Angiography, Stress Dual-Energy CT Perfusion, and Stress Perfusion Single-Photon Emission Computed Tomography for Coronary Artery Disease: Comparison with Combined Invasive Coronary Angiography and Stress Perfusion Cardiac MRI

ObjectiveTo investigate the diagnostic performance of coronary computed tomography angiography (CCTA), stress dual-energy computed tomography perfusion (DE-CTP), stress perfusion single-photon emission computed tomography (SPECT), and the combinations of CCTA with myocardial perfusion imaging (CCTA + DE-CTP and CCTA + SPECT) for identifying coronary artery stenosis that causes myocardial hypoperfusion. Combined invasive coronary angiography (ICA) and stress perfusion cardiac magnetic resonance (SP-CMR) imaging are used as the reference standard.Materials and MethodsWe retrospectively reviewed the records of 25 patients with suspected coronary artery disease, who underwent CCTA, DE-CTP, SPECT, SP-CMR, and ICA. The reference standard was defined as ≥ 50% stenosis by ICA, with a corresponding myocardial hypoperfusion on SP-CMR.ResultsFor per-vascular territory analysis, the sensitivities of CCTA, DE-CTP, SPECT, CCTA + DE-CTP, and CCTA + SPECT were 96, 96, 68, 93, and 68%, respectively, and specificities were 72, 75, 89, 85, and 94%, respectively. The areas under the receiver operating characteristic curve (AUCs) were 0.84 ± 0.05, 0.85 ± 0.05, 0.79 ± 0.06, 0.89 ± 0.04, and 0.81 ± 0.06, respectively. For per-patient analysis, the sensitivities of CCTA, DE-CTP, SPECT, CCTA + DE-CTP, and CCTA + SPECT were 100, 100, 89, 100, and 83%, respectively; the specificities were 14, 43, 57, 43, and 57%, respectively; and the AUCs were 0.57 ± 0.13, 0.71 ± 0.11, 0.73 ± 0.11, 0.71 ± 0.11, and 0.70 ± 0.11, respectively.ConclusionThe combination of CCTA and DE-CTP enhances specificity without a loss of sensitivity for detecting hemodynamically significant coronary artery stenosis, as defined by combined ICA and SP-CMR.

Evaluation of splenic switch off in a tertiary imaging centre: validation and assessment of utility.

Adenosine can induce splenic vasoconstriction (splenic switch-off, SSO). In this study, we aim to evaluate the utility of identifying a lack of SSO for detecting false-negative adenosine stress perfusion cardiac magnetic resonance (CMR) scans. We visually analysed 492 adenosine stress perfusion CMR scans reported as negative in a cohort of patients with no previous history of coronary artery disease. A lack of SSO was identified in 11%. We quantified the phenomenon by drawing regions of interest on the spleen and comparing intensity between stress and rest scans, the spleen intensity ratio (SIR). Inter-rater agreement for qualitative determination of SSO was κ = 0.81 and inter-class correlation for quantitative determination of SSO was 0.94. The optimal threshold for SIR as an indicator of SSO was 0.40 (sensitivity = 82.5%, specificity = 92.3%, AUC = 0.91). 23 065 CMR scans and 9926 invasive coronary angiogram reports were retrospectively examined to identify patients with negative CMR scans who required coronary intervention in the subsequent 12 months (false negatives). We compared these scans with true positives who had positive adenosine stress perfusion CMR scans followed by coronary intervention. The rate of lack of SSO was 20.7% in the false-negative group versus 13.1% in true positives (P = 0.37). The lack of SSO is prevalent, easily measureable, and has potential to improve on haemodynamic criteria as a marker of adenosine understress in CMR perfusion scans.

Stress Perfusion Cardiac Magnetic Resonance Imaging Effectively Risk Stratifies Diabetic Patients With Suspected Myocardial Ischemia.

Diabetics remain at high risk of cardiovascular disease and mortality despite advancements in medical therapy. Noninvasive cardiac risk profiling is often more difficult in diabetics owing to the prevalence of silent ischemia with unrecognized myocardial infarction, reduced exercise capacity, nondiagnostic electrocardiographic changes, and balanced ischemia from diffuse epicardial coronary atherosclerosis and microvascular dysfunction. A consecutive cohort of 173 patients with diabetes mellitus (mean age, 61.7±11.9 years; 37% women) with suspected myocardial ischemia underwent stress perfusion cardiac magnetic resonance imaging. Patients were evaluated for adverse cardiac events after cardiac magnetic resonance imaging with mean follow-up time of 2.9±2.5 years. Mean hemoglobin A1c for the population was 7.9±1.8%. Primary end point was a composite of cardiac death and nonfatal myocardial infarction. Diabetics with no inducible ischemia (n=94) experienced an annualized event rate of 1.4% compared with 8.2% (P=0.0003) in those with inducible ischemia (n=79). Diabetics without late gadolinium enhancement or inducible ischemia had a low annual cardiac event rate (0.5% per year). The presence of inducible ischemia was the strongest unadjusted predictor (hazard ratio, 4.86; P<0.01) for cardiac death and nonfatal myocardial infarction. This association remained robust in adjusted stepwise multivariable Cox regression analysis (hazard ratio, 4.28; P=0.02). In addition, categorical net reclassification index using 5-year risk cutoffs of 5% and 10% resulted in reclassification of 43.4% of the diabetic cohort with net reclassification index of 0.38 (95% confidence interval, 0.20-0.56; P<0.0001). Stress perfusion cardiac magnetic resonance imaging provided independent prognostic utility and effectively reclassified risk in patients with diabetes mellitus referred for ischemic assessment. Further evaluation is required to determine whether a noninvasive imaging strategy with cardiac magnetic resonance imaging can favorably affect downstream outcomes and improve cost-effectiveness of care in diabetics.

The Clinical Value of Stress Perfusion Cardiac Magnetic Resonance Imaging in Low- and Intermediate-Risk Patients with Symptoms Concerning for Acute Coronary Syndrome

The Clinical Value of Stress Perfusion Cardiac Magnetic Resonance Imaging in Low- and Intermediate-Risk Patients with Symptoms Concerning for Acute Coronary Syndrome

Comparison of Myocardial Transmural Perfusion Gradient by Magnetic Resonance Imaging to Fractional Flow Reserve in Patients With Suspected Coronary Artery Disease

The goal of this study was to evaluate the diagnostic accuracy of transmural perfusion gradient (TPG) and transmural perfusion gradient reserve (TPGR) with 3.0 T cardiac magnetic resonance (CMR) against invasively determined fractional flow reserve (FFR) to detect coronary artery stenosis. Quantitative analysis of myocardial perfusion with CMR to diagnosis coronary artery disease (CAD) has been widely accepted. However, traditional transmural myocardial perfusion analysis with CMR neglects that endocardium is more vulnerable to ischemia than epicardium. TPG and TPGR can take the inhomogenous perfusion impairment into account and be more sensitive and specific for diagnosis of CAD. In this study, 71 patients (57 men, age 60.1 ± 6.4 years) with known or suspected CAD referred for invasive angiography study underwent rest and adenosine-induced stress CMR perfusion imaging scan. FFR was attempted to be measured in all major epicardial coronary arteries. FFR ≤0.75 was regarded to indicate a hemodynamic significant coronary lesion. A TPG ≤0.85 predicted significant CAD with sensitivity and specificity of 74.55% and 83.65%, respectively. Sensitivity and specificity of TPGR ≤0.81 were 90.91% and 89.94%, respectively. Area under the receiver-operating curve to detect FFR ≤0.75 was 0.86 for TPG and 0.95 for TPGR. TPGR yielded significantly better sensitivity and specificity for diagnosis of CAD than traditional myocardial blood flow, myocardial perfusion reserve, and TPG (p < 0.0001). In conclusion, TPG and TPGR analyses with MRI are capable of detecting hemodynamic stenosis of coronary artery and superior to traditional myocardial perfusion analysis. Furthermore, TPGR appears to be superior to TPG in the diagnosis of coronary artery stenosis.

Is the diagnostic yield of myocardial stress perfusion MRI impaired by three-vessel coronary artery disease?

Three-vessel coronary artery disease (CAD) comes along with globally reduced myocardial perfusion potentially restricting the demarcation of regional hypoperfusion in stress perfusion cardiac magnetic resonance imaging (MRI). To evaluate whether stress perfusion cardiac MRI is capable of detecting myocardial hypoperfusion in patients with 3-vessel CAD reliably. Two hundred and five patients with symptoms of CAD were included. The examination protocol comprised imaging of myocardial perfusion at stress (0.14 mg/kg/min adenosine for 4 min) using a 2D saturation recovery gradient echo sequence after administration of gadobutrol (0.1 mmol/kg body weight). Perfusion sequences were assessed qualitatively by two experienced observers. Coronary angiography served as standard of reference. Sensitivity and specificity for hemodynamically relevant stenoses in patients with 0-, 1-, 2-, 3-vessel coronary artery disease were 100%/91%, 91%/73%, 90%/71%, 92%/64%; positive/negative predictive value, 67%/100%, 91%/73%, 83%/81%, 93%/58%; diagnostic accuracy, 93%/87%/83%/87%, respectively. The negative predictive value in patients with 3-vessel CAD was lower than in patients with 0- and 2-vessel CAD and the specificity lower than in patients with no CAD whereas the positive predictive value was higher than in patients with no CAD. The other proportions did not differ significantly between the groups. The diagnostic value of stress perfusion cardiac MRI in patients with 3-vessel CAD is comparable to results in patients with 1- or 2-vessel CAD. In the rare event that stress perfusion images do not depict regional hypoperfusion in patients with severe 3-vessel CAD, myocardial ischemia could be identified by reduced semi-quantitative perfusion parameters.