Noninfarcted myocardium: correlation between dynamic first-pass contrast-enhanced myocardial MR imaging and quantitative coronary angiography

Predictive value of a positive stress single-photon emission computed tomography or stress cardiac magnetic resonance for ruling in obstructive coronary artery disease in a real-world setting

INTRODUCTION AND OBJECTIVES

Randomized controlled trials comparing stress cardiac magnetic resonance (CMR) and single-photon emission computed tomography (SPECT) suggest similar diagnostic accuracy for detecting obstructive coronary artery disease (CAD). There are few data on whether this remains true in routine clinical practice. The aim of this study was to assess clinical and angiographic characteristics of patients undergoing invasive coronary angiography (ICA) after stress CMR or SPECT, and to compare their positive predictive value with published results from the CE-MARC trial.

METHODS

In this retrospective tertiary-center analysis, we included 429 patients undergoing ICA after a positive stress CMR or positive SPECT performed within the previous 12 months. Obstructive CAD was defined as any coronary artery stenosis ≥50% in a vessel compatible with the ischemic territory on stress testing.

RESULTS

Of the total 429 patients, 356 (83%) were referred after a positive SPECT, and 73 (17%) after a positive stress CMR. Patients did not differ according to age, cardiovascular risk factors, previous revascularization or left ventricular dysfunction, but patients with SPECT were more frequently male (p=0.046). The prevalence of obstructive CAD was similar in patients with positive SPECT vs. positive stress CMR (76.1% vs. 80.8%, respectively, p=0.385). The positive predictive values of both techniques were similar to those reported in the CE-MARC trial.

CONCLUSION

In this tertiary center analysis, stress CMR and SPECT showed similar positive predictive values, comparable to those reported in the CE-MARC trial. This finding supports the emerging adoption of CMR in clinical practice for the diagnosis and management of CAD.

Diagnostic and Prognostic Value of Stress Cardiovascular Magnetic Resonance Imaging in Patients With Known or Suspected Coronary Artery Disease: A Systematic Review and Meta-analysis

Importance

The clinical utility of stress cardiovascular magnetic resonance imaging (CMR) in stable chest pain is still debated, and the low-risk period for adverse cardiovascular (CV) events after a negative test result is unknown.

Objective

To provide contemporary quantitative data synthesis of the diagnostic accuracy and prognostic value of stress CMR in stable chest pain.

Data Sources

PubMed and Embase databases, the Cochrane Database of Systematic Reviews, PROSPERO, and the ClinicalTrials.gov registry were searched for potentially relevant articles from January 1, 2000, through December 31, 2021.

Study Selection

Selected studies evaluated CMR and reported estimates of diagnostic accuracy and/or raw data of adverse CV events for participants with either positive or negative stress CMR results. Prespecified combinations of keywords related to the diagnostic accuracy and prognostic value of stress CMR were used. A total of 3144 records were evaluated for title and abstract; of those, 235 articles were included in the full-text assessment of eligibility. After exclusions, 64 studies (74 470 total patients) published from October 29, 2002, through October 19, 2021, were included.

Data Extraction and Synthesis

This systematic review and meta-analysis adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses.

Main Outcomes and Measures

Diagnostic odds ratios (DORs), sensitivity, specificity, area under the receiver operating characteristic curve (AUROC), odds ratio (OR), and annualized event rate (AER) for all-cause death, CV death, and major adverse cardiovascular events (MACEs) defined as the composite of myocardial infarction and CV death.

Results

A total of 33 diagnostic studies pooling 7814 individuals and 31 prognostic studies pooling 67 080 individuals (mean [SD] follow-up, 3.5 [2.1] years; range, 0.9-8.8 years; 381 357 person-years) were identified. Stress CMR yielded a DOR of 26.4 (95% CI, 10.6-65.9), a sensitivity of 81% (95% CI, 68%-89%), a specificity of 86% (95% CI, 75%-93%), and an AUROC of 0.84 (95% CI, 0.77-0.89) for the detection of functionally obstructive coronary artery disease. In the subgroup analysis, stress CMR yielded higher diagnostic accuracy in the setting of suspected coronary artery disease (DOR, 53.4; 95% CI, 27.7-103.0) or when using 3-T imaging (DOR, 33.2; 95% CI, 19.9-55.4). The presence of stress-inducible ischemia was associated with higher all-cause mortality (OR, 1.97; 95% CI, 1.69-2.31), CV mortality (OR, 6.40; 95% CI, 4.48-9.14), and MACEs (OR, 5.33; 95% CI, 4.04-7.04). The presence of late gadolinium enhancement (LGE) was associated with higher all-cause mortality (OR, 2.22; 95% CI, 1.99-2.47), CV mortality (OR, 6.03; 95% CI, 2.76-13.13), and increased risk of MACEs (OR, 5.42; 95% CI, 3.42-8.60). After a negative test result, pooled AERs for CV death were less than 1.0%.

Conclusion and Relevance

In this study, stress CMR yielded high diagnostic accuracy and delivered robust prognostication, particularly when 3-T scanners were used. While inducible myocardial ischemia and LGE were associated with higher mortality and risk of MACEs, normal stress CMR results were associated with a lower risk of MACEs for at least 3.5 years.

Advances in Myocardial Perfusion MR Imaging: Physiological Implications, the Importance of Quantitative Analysis, and Impact on Patient Care in Coronary Artery Disease

Stress myocardial perfusion imaging (MPI) is the preferred test in patients with intermediate-to-high clinical likelihood of coronary artery disease (CAD) and can be used as a gatekeeper to avoid unnecessary revascularization. Cardiac magnetic resonance (CMR) has a number of favorable characteristics, including: (1) high spatial resolution that can delineate subendocardial ischemia; (2) comprehensive assessment of morphology, global and regional cardiac functions, tissue characterization, and coronary artery stenosis; and (3) no radiation exposure to patients. According to meta-analysis studies, the diagnostic accuracy of perfusion CMR is comparable to positron emission tomography (PET) and perfusion CT, and is better than single-photon emission CT (SPECT) when fractional flow reserve (FFR) is used as a reference standard. In addition, stress CMR has an excellent prognostic value. One meta-analysis study demonstrated the annual event rate of cardiovascular death or non-fatal myocardial infarction was 4.9% and 0.8%, respectively, in patients with positive and negative stress CMR. Quantitative assessment of perfusion CMR not only allows the objective evaluation of regional ischemia but also provides insights into the pathophysiology of microvascular disease and diffuse subclinical atherosclerosis. For accurate quantification of myocardial perfusion, saturation correction of arterial input function is important. There are two major approaches for saturation correction, one is a dual-bolus method and the other is a dual-sequence method. Absolute quantitative mapping with myocardial perfusion CMR has good accuracy in detecting coronary microvascular dysfunction. Flow measurement in the coronary sinus (CS) with phase contrast cine CMR is an alternative approach to quantify global coronary flow reserve (CFR). The measurement of global CFR by quantitative analysis of perfusion CMR or flow measurement in the CS permits assessment of microvascular disease and diffuse subclinical atherosclerosis, which may provide improved prediction of future event risk in patients with suspected or known CAD. Multi-institutional studies to validate the diagnostic and prognostic values of quantitative perfusion CMR approaches are required.

Prognostic value of vasodilator stress perfusion CMR in patients with previous coronary artery bypass graft

AIMS 

The accuracy and prognostic value of stress perfusion cardiac magnetic resonance (CMR) are established in coronary artery disease (CAD) patients. Because myocardial contrast kinetics may be altered after coronary artery bypass graft (CABG), most studies excluded CABG patients. This study aimed to assess the prognostic value of vasodilator stress perfusion CMR in CABG patients.

METHODS AND RESULTS 

Consecutive CABG patients referred for stress CMR were retrospectively included and followed for the occurrence of major adverse cardiovascular events (MACE) including cardiovascular (CV) death or non-fatal myocardial infarction (MI). Cox regression analyses were performed to determine the prognostic association of inducible ischaemia and late gadolinium enhancement (LGE) by CMR. Of 866 consecutive CABG patients, 852 underwent the stress CMR protocol and 771 (89%) completed the follow-up [median (interquartile range) 4.2 (3.3-6.2) years]. There were 85 MACE (63 CV deaths and 22 non-fatal MI). Using Kaplan-Meier analysis, the presence of inducible ischaemia identified the occurrence of MACE [hazard ratio (HR) 3.52, 95% confidence interval (CI): 2.27-5.48; P < 0.001] and CV death (HR 2.55, 95% CI: 1.52-4.25; P < 0.001). In a multivariable stepwise Cox regression including clinical characteristics and CMR indexes, the presence of inducible ischaemia was an independent predictor of a higher incidence of MACE (HR 3.22, 95% CI: 2.06-5.02; P < 0.001) and CV death (HR 2.15, 95% CI: 1.28-3.62; P = 0.003), and the same was observed for LGE (both P = 0.02).

CONCLUSION 

Stress CMR has a good discriminative prognostic value in patients after CABG, with a higher incidence of MACE and CV death in patients with inducible ischaemia and/or LGE.

Recent Advances in Vascular Imaging

Recent advances in vascular imaging have enabled us to uncover the underlying mechanisms of vascular diseases both ex vivo and in vivo. In the past decade, efforts have been made to establish various methodologies for evaluation of atherosclerotic plaque progression and vascular inflammatory changes in addition to biomarkers and clinical manifestations. Several recent publications in Arteriosclerosis, Thrombosis, and Vascular Biology highlighted the essential roles of in vivo and ex vivo vascular imaging, including magnetic resonance image, computed tomography, positron emission tomography/scintigraphy, ultrasonography, intravascular ultrasound, and most recently, optical coherence tomography, all of which can be used in bench and clinical studies at relative ease. With new methods proposed in several landmark studies, these clinically available imaging modalities will be used in the near future. Moreover, future development of intravascular imaging modalities, such as optical coherence tomography-intravascular ultrasound, optical coherence tomography-near-infrared autofluorescence, polarized-sensitive optical coherence tomography, and micro-optical coherence tomography, are anticipated for better management of patients with cardiovascular disease. In this review article, we will overview recent advances in vascular imaging and ongoing works for future developments.

Diagnostic performance of coronary angiography utilizing intraprocedural 320-row computed tomography with minimal contrast medium

Recently developed coronary angiography with intraprocedural 320-row computed tomography can be performed in a catheterization laboratory (XACT) by injecting contrast medium from a place close to the coronary arteries, thereby requiring a minimal amount of contrast medium. However, its clinical application has not yet been established. This study aimed to evaluate the diagnostic accuracy of XACT angiography with a minimal volume of contrast medium in patients with suspected coronary artery disease (CAD). A total of 167 coronary segments were analyzed in 14 patients (9 males, median age 70 years) with suspected CAD by XACT angiography with 7.5 ml of contrast medium and invasive coronary angiography (ICA) with standard techniques. The segmental-based diagnostic accuracy of XACT angiography in detecting stenosis of ≥ 50% and ≥ 75% and visualized by ICA was good (sensitivity: 74% and 62%, specificity: 99% and 99%, positive predictive value: 93% and 80%, and negative predictive value: 97% and 97%, respectively). These results suggest that XACT angiography with a very low amount of contrast medium may have strong clinical utility for screening coronary arteries in patients with renal dysfunction or undergoing clinical procedures such as pacemaker implantation.

Cardiac Magnetic Resonance Versus Single-Photon Emission Computed Tomography for Detecting Coronary Artery Disease and Myocardial Ischemia: Comparison with Coronary Angiography

Background: This study aimed to compare the diagnostic accuracy of stress single-photon emission computed tomography (SPECT) and stress cardiac magnetic resonance (CMR) for the assessment of coronary artery disease (CAD) in the same patients, using coronary angiography as the reference standard. Methods: Thirty patients with known or suspected CAD who were referred for exercise SPECT myocardial perfusion imaging (MPI) for the evaluation of myocardial ischemia underwent stress CMR MPI and computed tomography coronary angiography (CTCA) or selective coronary angiography (SCA). The data from the two stress modalities were compared against the data from angiography. Results: In our study population, 30% of the recruited subjects had significant CAD. The CMR sensitivity for the detection of significant CAD and/or myocardial ischemia was 89% and specificity was 76%. For SPECT, the corresponding sensitivity was 78% and specificity was 52%. The negative predictive value was 92% for CMR and 83% for SPECT. The receiver-operating characteristic (ROC) analysis evaluating the presence of significant CAD, CMR (area under the curve (AUC) 0.78) outperformed SPECT (AUC 0.59) (p < 0.01). The ROC analysis evaluating the presence of myocardial ischemia was also in favor of CMR (AUC 0.82) versus SPECT (AUC 0.67) (p < 0.01). Conclusions: CMR has high diagnostic accuracy for the detection of CAD and stress-induced ischemia and appears to outperform SPECT. CMR may thus be the preferred noninvasive imaging modality to assess patients with known or suspected CAD.

Danish study of Non-Invasive testing in Coronary Artery Disease 2 (Dan-NICAD 2): Study design for a controlled study of diagnostic accuracy

BACKGROUND

Coronary computed tomography angiography (CTA) is the preferred primary diagnostic modality when examining patients with low to intermediate pre-test probability of coronary artery disease (CAD). Only 20-30% of these have potentially obstructive CAD. Because of the relatively poor positive predictive value of coronary CTA, unnecessary invasive coronary angiographies (ICAs) are conducted with the costs and risks associated with the procedure. Hence, an optimized diagnostic CAD algorithm may reduce the numbers of ICAs not followed by revascularization. The Dan-NICAD 2 study has 3 equivalent main aims: (1) To examine the diagnostic precision of a sound-based diagnostic algorithm, The CADScor®System (Acarix A/S, Denmark), in patients with a low to intermediate pre-test risk of CAD referred to a primary examination by coronary CTA. We hypothesize that the CADScor®System provides better stratification prior to coronary CTA than clinical risk stratification scores alone. (2) To compare the diagnostic accuracy of 3T cardiac magnetic resonance imaging (3T CMRI), ⁸²rubidium positron emission tomography (⁸²Rb-PET), and CT-derived fractional flow reserve (FFR_CT) in patients where obstructive CAD cannot be ruled out by coronary CTA using ICA fractional flow reserve (FFR) as reference standard. (3) To compare the diagnostic performance of quantitative flow ratio (QFR) and ICA-FFR in patients with low to intermediate pre-test probability of CAD using ⁸²Rb-PET as reference standard.

METHODS

Dan-NICAD 2 is a prospective, multicenter, cross-sectional study including approximately 2,000 patients with low to intermediate pre-test probability of CAD and without previous history of CAD. Patients are referred to coronary CTA because of symptoms suggestive of CAD, as evaluated by a cardiologist. Patient interviews, sound recordings, and blood samples are obtained in connection with the coronary CTA. If coronary CTA does not rule out obstructive CAD, patients will be examined by 3T CMRI ⁸²Rb-PET, FFR_CT, ICA, and FFR. Reference standard is ICA-FFR. Obstructive CAD is defined as an FFR ≤0.80 or as high-grade stenosis (>90% diameter stenosis) by visual assessment. Diagnostic performance will be evaluated as sensitivity, specificity, predictive values, likelihood ratios, calibration, and discrimination. Enrolment started January 2018 and is expected to be completed by June 2020. Patients are followed for 10 years after inclusion.

DISCUSSION

The results of the Dan-NICAD 2 study are expected to contribute to the improvement of diagnostic strategies for patients suspected of CAD in 3 different steps: risk stratification prior to coronary CTA, diagnostic strategy after coronary CTA, and invasive wireless QFR analysis as an alternative to ICA-FFR.

Data on diagnostic performance of stress perfusion cardiac magnetic resonance for coronary artery disease detection at the vessel level

Stress perfusion cardiac magnetic resonance (CMR) has been proposed as an important gatekeeper for invasive coronary angiography (ICA) and percutaneous coronary interventions (PCI) in patients evaluated for possible coronary artery disease (CAD) (Fihn et al., 2012; Montalescot et al., 2013) [1], [2]. Several meta-analyses have evaluated the accuracy of stress perfusion CMR to diagnose CAD at the vessel level (Danad et al., 2017; Dai et al., 2016; Jiang et al., 2016; Takx et al., 2015; Li et al., 2015; Desai and Jha, 2013; Jaarsma et al. 2012; Hamon et al., 2010; Nandalur et al. 2007) [3], [4], [5], [6], [7], [8], [9], [10], [11]. However, they included in the same analysis studies with different definitions of significant CAD (i.e. fractional flow reserve [FFR] < 0.75 and < 0.80 or coronary stenosis ≥ 50% and ≥ 70%), magnetic field strength (1.5 or 3 Tesla [T]), and study protocol (integration or not of late gadolinium enhancement [LGE] into stress perfusion protocol). Data of 34 studies (6091 arteries) have been pooled with the aim of analyzing the accuracy of stress perfusion CMR for the diagnosis of ischemic heart disease at the vessel level according to different definitions of significant CAD, magnetic field strength and study protocol (Arnold et al., 2010; Bettencourt et al., 2013; Cheng et al., 2007; Chiribiri et al., 2013; Cury et al., 2006; De Mello et al., 2012; Donati et al., 2010; Ebersberger et al., 2013; Gebker et al., 2008; Greulich et al., 2015; Hussain et al., 2016; Ishida et al., 2005, 2003; Kamiya et al., 2014; Kitagawa et al., 2008; Klein et al., 2008; Klem et al., 2006; Klumpp et al., 2010; Krittayaphong et al., 2009; Lockie et al., 2011; Ma et al., 2012; Merkle et al., 2007; Meyer et al., 2008; Mor-Avi et al., 2008; Pan et al., 2015; Papanastasiou et al., 2016; Pons Lladó et al., 2004; Sakuma et al., 2005; Salerno et al., 2014; Scheffel et al., 2010; van Werkhoven et al., 2010; Walcher et al., 2013; Watkins et al., 2009; Yun et al., 2015) [12–45]. This article describes data related article titled “Diagnostic Performance of Stress Perfusion Cardiac Magnetic Resonance for the Detection of Coronary Artery Disease” (Kiaos et al., submitted for publication) [46].

Rapid rest/stress regadenoson ungated perfusion CMR for detection of coronary artery disease in patients with atrial fibrillation

Cardiovascular magnetic resonance (CMR) perfusion has been established as a useful imaging modality for the detection of coronary artery disease (CAD). However, there are several limitations when applying standard, ECG-gated stress/rest perfusion CMR to patients with atrial fibrillation (AF). In this study we investigate an approach with no ECG gating and a rapid rest/stress perfusion protocol to determine its accuracy for detection of CAD in patients with AF. 26 patients with AF underwent a rapid rest/regadenoson stress CMR perfusion imaging protocol, and all patients had X-ray coronary angiography. An ungated radial myocardial perfusion sequence was used. Imaging protocol included: rest perfusion image acquisition, followed nearly immediately by administration of regadenoson to induce hyperemia, 60 s wait, and stress image acquisition. CMR perfusion images were interpreted by three blinded readers as normal or abnormal. Diagnostic accuracy was evaluated by comparison to X-ray angiography. 21 of the CMR rest/stress perfusion scans were negative, and 5 were positive by angiography criteria. Majority results of the ungated datasets from all of the readers showed a sensitivity, specificity and accuracy of 80, 100 and 96%, respectively, for detection of CAD. An ungated, rapid rest/stress regadenoson perfusion CMR protocol appears to be useful for the diagnosis of obstructive CAD in patients with AF.

Danish study of Non-Invasive testing in Coronary Artery Disease (Dan-NICAD): study protocol for a randomised controlled trial

BACKGROUND

Coronary computed tomography angiography (CCTA) is an established method for ruling out coronary artery disease (CAD). Most patients referred for CCTA do not have CAD and only approximately 20-30 % of patients are subsequently referred to further testing by invasive coronary angiography (ICA) or non-invasive perfusion evaluation due to suspected obstructive CAD. In cases with severe calcifications, a discrepancy between CCTA and ICA often occurs, leading to the well-described, low-diagnostic specificity of CCTA. As ICA is cost consuming and involves a risk of complications, an optimized algorithm would be valuable and could decrease the number of ICAs that do not lead to revascularization. The primary objective of the Dan-NICAD study is to determine the diagnostic accuracy of cardiac magnetic resonance imaging (CMRI) and myocardial perfusion scintigraphy (MPS) as secondary tests after a primary CCTA where CAD could not be ruled out. The secondary objective includes an evaluation of the diagnostic precision of an acoustic technology that analyses the sound of coronary blood flow. It may potentially provide better stratification prior to CCTA than clinical risk stratification scores alone.

METHODS/DESIGN

Dan-NICAD is a multi-centre, randomised, cross-sectional trial, which will include approximately 2,000 patients without known CAD, who were referred to CCTA due to a history of symptoms suggestive of CAD and a low-risk to intermediate-risk profile, as evaluated by a cardiologist. Patient interview, sound recordings, and blood samples are obtained in connection with the CCTA. All patients with suspected obstructive CAD by CCTA are randomised to either stress CMRI or stress MPS, followed by ICA with fractional flow reserve (FFR) measurements. Obstructive CAD is defined as an FFR below 0.80 or as high-grade stenosis (>90 % diameter stenosis) by visual assessment. Diagnostic performance is evaluated as sensitivity, specificity, predictive values, likelihood ratios, and C statistics. Enrolment commenced in September 2014 and is expected to be complete in May 2016.

DISCUSSION

Dan-NICAD is designed to assess whether a secondary perfusion examination after CCTA could safely reduce the number of ICAs where revascularization is not required. The results are expected to add knowledge about the optimal algorithm for diagnosing CAD.

TRIAL REGISTRATION

Clinicaltrials.gov identifier, NCT02264717 . Registered on 26 September 2014.

Evaluation of an automated method for arterial input function detection for first-pass myocardial perfusion cardiovascular magnetic resonance

BACKGROUND

Quantitative assessment of myocardial blood flow (MBF) with first-pass perfusion cardiovascular magnetic resonance (CMR) requires a measurement of the arterial input function (AIF). This study presents an automated method to improve the objectivity and reduce processing time for measuring the AIF from first-pass perfusion CMR images. This automated method is used to compare the impact of different AIF measurements on MBF quantification.

METHODS

Gadolinium-enhanced perfusion CMR was performed on a 1.5 T scanner using a saturation recovery dual-sequence technique. Rest and stress perfusion series from 270 clinical studies were analyzed. Automated image processing steps included motion correction, intensity correction, detection of the left ventricle (LV), independent component analysis, and LV pixel thresholding to calculate the AIF signal. The results were compared with manual reference measurements using several quality metrics based on the contrast enhancement and timing characteristics of the AIF. The median and 95% confidence interval (CI) of the median were reported. Finally, MBF was calculated and compared in a subset of 21 clinical studies using the automated and manual AIF measurements.

RESULTS

Two clinical studies were excluded from the comparison due to a congenital heart defect present in one and a contrast administration issue in the other. The proposed method successfully processed 99.63% of the remaining image series. Manual and automatic AIF time-signal intensity curves were strongly correlated with median correlation coefficient of 0.999 (95% CI [0.999, 0.999]). The automated method effectively selected bright LV pixels, excluded papillary muscles, and required less processing time than the manual approach. There was no significant difference in MBF estimates between manually and automatically measured AIFs (p = NS). However, different sizes of regions of interest selection in the LV cavity could change the AIF measurement and affect MBF calculation (p = NS to p = 0.03).

CONCLUSION

The proposed automatic method produced AIFs similar to the reference manual method but required less processing time and was more objective. The automated algorithm may improve AIF measurement from the first-pass perfusion CMR images and make quantitative myocardial perfusion analysis more robust and readily available.

Comparison of stress cardiovascular magnetic resonance imaging (CMR) with stress nuclear perfusion for the diagnosis of coronary artery disease

OBJECTIVES

To assess the diagnostic performance of stress cardiac magnetic resonance (stress CMR) vs stress single-photon emission computed tomography (SPECT) in patients presenting to the emergency department (ED) with chest pain.

BACKGROUND

SPECT imaging is the most utilized outpatient procedure in the United States. The diagnostic accuracy of SPECT can be limited by soft tissue attenuation and low spatial resolution. Stress CMR has much higher spatial resolution and without the susceptibility to soft tissue attenuation.

METHODS

Eighty-seven patients without a history of CAD presenting to the ED with chest pain were prospectively enrolled. Patients underwent both stress CMR and stress SPECT imaging within 12 hours of presentation. Both the stress imaging tests were interpreted immediately for clinical purposes and coronary angiography was performed if either was abnormal. Patients were considered to have significant CAD if identified by angiography (≥50%) or if a cardiac event (cardiac death, myocardial infarction or revascularization) occurred during follow-up (mean 2.6 ± 1.1 years).

RESULTS

Thirty-seven patients were referred for coronary angiography; 29 due to a positive stress test and eight patients for persistent chest pain despite two negative stress tests. There were 22 patients who had significant CAD (≥50%). The remaining patients were followed for 2.6 ± 1.1 years. At the conclusion of the follow-up period, there were four clinical events. The sensitivity, specificity, and diagnostic accuracy of CMR are 85%, 93%, and 89%, respectively. The sensitivity, specificity, and diagnostic accuracy of stress SPECT are 84%, 91%, and 88%, respectively.

CONCLUSION

Stress CMR has similar diagnostic accuracy as stress SPECT in diagnosis of CAD.

Factors associated with false-negative cardiovascular magnetic resonance perfusion studies: A Clinical evaluation of magnetic resonance imaging in coronary artery disease (CE-MARC) substudy

Purpose

To examine factors associated with false‐negative cardiovascular magnetic resonance (MR) perfusion studies within the large prospective Clinical Evaluation of MR imaging in Coronary artery disease (CE‐MARC) study population. Myocardial perfusion MR has excellent diagnostic accuracy to detect coronary heart disease (CHD). However, causes of false‐negative MR perfusion studies are not well understood.

Materials and Methods

CE‐MARC prospectively recruited patients with suspected CHD and mandated MR, myocardial perfusion scintigraphy, and invasive angiography. This subanalysis identified all patients with significant coronary stenosis by quantitative coronary angiography (QCA) and MR perfusion (1.5T, T₁‐weighted gradient echo), using the original blinded image read. We explored patient and imaging characteristics related to false‐negative or true‐positive MR perfusion results, with reference to QCA. Multivariate regression analysis assessed the likelihood of false‐negative MR perfusion according to four characteristics: poor image quality, triple‐vessel disease, inadequate hemodynamic response to adenosine, and Duke jeopardy score (angiographic myocardium‐at‐risk score).

Results

In all, 265 (39%) patients had significant angiographic disease (mean age 62, 79% male). Thirty‐five (5%) had false‐negative and 230 (34%) true‐positive MR perfusion. Poor MR perfusion image quality, triple‐vessel disease, and inadequate hemodynamic response were similar between false‐negative and true‐positive groups (odds ratio, OR [95% confidence interval, CI]: 4.1 (0.82–21.0), P = 0.09; 1.2 (0.20–7.1), P = 0.85, and 1.6 (0.65–3.8), P = 0.31, respectively). Mean Duke jeopardy score was significantly lower in the false‐negative group (2.6 ± 1.7 vs. 5.4 ± 3.0, OR 0.34 (0.21–0.53), P < 0.0001).

Conclusion

False‐negative cardiovascular MR perfusion studies are uncommon, and more common in patients with lower angiographic myocardium‐at‐risk. In CE‐MARC, poor image quality, triple‐vessel disease, and inadequate hemodynamic response were not significantly associated with false‐negative MR perfusion. J. MAGN. RESON. IMAGING 2016;43:566–573.

Comprehensive assessment of radiation dose estimates for the CORE320 study

OBJECTIVE. The purpose of this study was to comprehensively study estimated radiation doses for subjects included in the main analysis of the Combined Non-invasive Coronary Angiography and Myocardial Perfusion Imaging Using 320 Detector Computed Tomography (CORE320) study ( ClinicalTrials.gov identifier NCT00934037), a clinical trial comparing combined CT angiography (CTA) and perfusion CT with the reference standard catheter angiography plus myocardial perfusion SPECT. SUBJECTS AND METHODS. Prospectively acquired data on 381 CORE320 subjects were analyzed in four groups of testing related to radiation exposure. Radiation dose estimates were compared between modalities for combined CTA and perfusion CT with respect to covariates known to influence radiation exposure and for the main clinical outcomes defined by the trial. The final analysis assessed variations in radiation dose with respect to several factors inherent to the trial. RESULTS. The mean radiation dose estimate for the combined CTA and perfusion CT protocol (8.63 mSv) was significantly (p < 0.0001 for both) less than the average dose delivered from SPECT (10.48 mSv) and the average dose from diagnostic catheter angiography (11.63 mSv). There was no significant difference in estimated CTA-perfusion CT radiation dose for subjects who had false-positive or false-negative results in the CORE320 main analyses in a comparison with subjects for whom the CTA-perfusion CT findings were in accordance with the reference standard SPECT plus catheter angiographic findings. CONCLUSION. Radiation dose estimates from CORE320 support clinical implementation of a combined CT protocol for assessing coronary anatomy and myocardial perfusion.

Diagnostic accuracy of stress perfusion CMR in comparison with quantitative coronary angiography: fully quantitative, semiquantitative, and qualitative assessment

OBJECTIVES

This study's primary objective was to determine the sensitivity, specificity, and accuracy of fully quantitative stress perfusion cardiac magnetic resonance (CMR) versus a reference standard of quantitative coronary angiography. We hypothesized that fully quantitative analysis of stress perfusion CMR would have high diagnostic accuracy for identifying significant coronary artery stenosis and exceed the accuracy of semiquantitative measures of perfusion and qualitative interpretation.

BACKGROUND

Relatively few studies apply fully quantitative CMR perfusion measures to patients with coronary disease and comparisons to semiquantitative and qualitative methods are limited.

METHODS

Dual bolus dipyridamole stress perfusion CMR exams were performed in 67 patients with clinical indications for assessment of myocardial ischemia. Stress perfusion images alone were analyzed with a fully quantitative perfusion (QP) method and 3 semiquantitative methods including contrast enhancement ratio, upslope index, and upslope integral. Comprehensive exams (cine imaging, stress/rest perfusion, late gadolinium enhancement) were analyzed qualitatively with 2 methods including the Duke algorithm and standard clinical interpretation. A 70% or greater stenosis by quantitative coronary angiography was considered abnormal.

RESULTS

The optimum diagnostic threshold for QP determined by receiver-operating characteristic curve occurred when endocardial flow decreased to <50% of mean epicardial flow, which yielded a sensitivity of 87% and specificity of 93%. The area under the curve for QP was 92%, which was superior to semiquantitative methods: contrast enhancement ratio: 78%; upslope index: 82%; and upslope integral: 75% (p = 0.011, p = 0.019, p = 0.004 vs. QP, respectively). Area under the curve for QP was also superior to qualitative methods: Duke algorithm: 70%; and clinical interpretation: 78% (p < 0.001 and p < 0.001 vs. QP, respectively).

CONCLUSIONS

Fully quantitative stress perfusion CMR has high diagnostic accuracy for detecting obstructive coronary artery disease. QP outperforms semiquantitative measures of perfusion and qualitative methods that incorporate a combination of cine, perfusion, and late gadolinium enhancement imaging. These findings suggest a potential clinical role for quantitative stress perfusion CMR.

Cardiac magnetic resonance and computed tomography angiography for clinical imaging of stable coronary artery disease. Diagnostic classification and risk stratification

Despite advances in the pharmacologic and interventional treatment of coronary artery disease (CAD), atherosclerosis remains the leading cause of death in Western societies. X-ray coronary angiography has been the modality of choice for diagnosing the presence and extent of CAD. However, this technique is invasive and provides limited information on the composition of atherosclerotic plaque. Coronary computed tomography angiography (CCTA) and cardiac magnetic resonance (CMR) have emerged as promising non-invasive techniques for the clinical imaging of CAD. Hereby, CCTA allows for visualization of coronary calcification, lumen narrowing and atherosclerotic plaque composition. In this regard, data from the CONFIRM Registry recently demonstrated that both atherosclerotic plaque burden and lumen narrowing exhibit incremental value for the prediction of future cardiac events. However, due to technical limitations with CCTA, resulting in false positive or negative results in the presence of severe calcification or motion artifacts, this technique cannot entirely replace invasive angiography at the present time. CMR on the other hand, provides accurate assessment of the myocardial function due to its high spatial and temporal resolution and intrinsic blood-to-tissue contrast. Hereby, regional wall motion and perfusion abnormalities, during dobutamine or vasodilator stress, precede the development of ST-segment depression and anginal symptoms enabling the detection of functionally significant CAD. While CT generally offers better spatial resolution, the versatility of CMR can provide information on myocardial function, perfusion, and viability, all without ionizing radiation for the patients. Technical developments with these 2 non-invasive imaging tools and their current implementation in the clinical imaging of CAD will be presented and discussed herein.

Cardiac MR perfusion imaging: where we are

To date, several clinical and multicentre studies have demonstrated the accuracy of perfusion cardiac magnetic resonance to detect ischaemia in comparison with quantitative coronary angiography, other noninvasive diagnostic techniques (single photon emission computed tomography; positron-emission tomography), and invasive haemodynamic measurements (fractional flow reserve). Moreover, the favourable safety profile and increasing availability contribute to make perfusion cardiac magnetic resonance one of the modalities of choice for the detection of myocardial ischaemia. Recently, the first evidence of the prognostic value of perfusion cardiac magnetic resonance results has also become available. This review summarises the technical and interpretation key points of perfusion cardiac magnetic resonance scan, the clinical indications, the most recent available literature about its diagnostic performance and prognostic value, and how perfusion cardiac magnetic resonance compares with other noninvasive techniques.

Cardiac MRI for myocardial ischemia

Proper assessment of the physiologic impact of coronary artery stenosis on the LV myocardium can affect patient prognosis and treatment decisions. Cardiac magnetic resonance imaging (CMR) assesses myocardial perfusion by imaging the myocardium during a first-pass transit of an intravenous gadolinium bolus, with spatial and temporal resolution substantially higher than nuclear myocardial perfusion imaging. Coupled with late gadolinium enhancement (LGE) imaging for infarction during the same imaging session, CMR with vasodilating stress perfusion imaging can qualitatively and quantitatively assess the myocardial extent of hypoperfusion from coronary stenosis independent of infarcted myocardium. This approach has been validated experimentally, and multiple clinical trials have established its diagnostic robustness when compared to stress single-photon emission computed tomography. In specialized centers, dobutamine stress CMR has been shown to have incremental diagnostic value above stress echocardiography due to its high imaging quality and ability to image the heart with no restriction of imaging window. This paper reviews the technical aspects, diagnostic utility, prognostic values, challenges to clinical adaptation, and future developments of stress CMR imaging.

Direct comparison of cardiovascular magnetic resonance and single-photon emission computed tomography for detection of coronary artery disease: a meta-analysis

Objective

To use direct comparative studies or randomised controlled trials to compare the accuracy of cardiac magnetic resonance (CMR) and single-photon emission computed tomography (SPECT) for the detection of obstructive coronary artery disease (CAD).

Materials and Methods

Various databases were searched for original articles published prior to June 2013. Studies were selected that performed both CMR and SPECT in the same or randomised patients to detect CAD and that presented sufficient data to allow construction of contingency tables. For each study, the true-positive, false-positive, true-negative, and false-negative values were extracted or derived, and 2×2 contingency tables were constructed. To reduce heterogeneity, the meta-analysis was carried out in two parts: (1) coronary territory-based analysis and (2) patient-based analysis.

Results

10 studies (5 studies based on patient, 4 studies based on coronary territory, and 1 study based on both) were included in the meta-analysis with a total of 1727 patients. The methodological quality was moderate. For part (1), the summary estimates were as follows: for CMR based on patient–a sensitivity of 0.79 (95% confidence interval: 0.72–0.84) and a specificity of 0.75 (0.65–0.83); for SPECT based on patient–a sensitivity of 0.70 (0.59–0.79) and a specificity of 0.76 (0.66–0.83). For part (2), the summary estimates for CMR based on coronary territory were a sensitivity of 0.80 (0.73–0.85) and a specificity of 0.87 (0.81–0.91), and the summary estimates for SPECT based on coronary territory were a sensitivity of 0.67 (0.60–0.72) and a specificity of 0.80 (0.75–0.84).

Conclusions

Compared with SPECT, CMR is more sensitive to detect CAD on a per-patient basis. Nonetheless, large scale, well-designed trials are necessary to assess its clinical value on a per-coronary territory basis.

Assessment of ischaemic burden in angiographic three-vessel coronary artery disease with high-resolution myocardial perfusion cardiovascular magnetic resonance imaging

Aims

This study compared the myocardial ischaemic burden (MIB) in patients with angiographic three-vessel coronary artery disease (3VD) using high-resolution and standard-resolution myocardial perfusion cardiovascular magnetic resonance (perfusion CMR) imaging.

Methods and results

One hundred and five patients undergoing coronary angiography had two separate stress/rest perfusion CMR studies, one with standard-resolution (2.5 mm in-plane) and another with high-resolution (1.6 mm in-plane). Quantitative coronary angiography was used to define patients with angiographic 3VD. Perfusion CMR images were anonymized, randomly ordered and visually reported by two observers acting in consensus and blinded to all clinical and angiographic data. Perfusion was graded in each segment on a four-point scale and summed to produce a perfusion score and estimate of MIB for each patient. In patients with angiographic 3VD (n = 35), high-resolution acquisition identified more abnormal segments (7.2 ± 3.8 vs. 5.3 ± 4.0; P = 0.004) and territories (2.4 ± 0.9 vs. 1.6 ± 1.1; P = 0.002) and a higher overall perfusion score (20.1 ± 7.7 vs. 11.9 ± 9.4; P < 0.0001) per patient compared with standard-resolution. The number of segments with subendocardial ischaemia was greater with high-resolution acquisition (195 vs. 101; P < 0.0001). Hypoperfusion in all three territories was identified in 57% of 3VD patients by high-resolution compared with only 29% by standard-resolution (P = 0.04). The area-under-the-curve (AUC) for detecting angiographic 3VD using the estimated MIB was significantly greater with high-resolution than standard-resolution acquisition (AUC = 0.90 vs. 0.69; P < 0.0001).

Conclusion

In patients with angiographic 3VD, the ischaemic burden detected by perfusion CMR is greater with high-resolution acquisition due to better detection of subendocardial ischaemia. High-resolution perfusion CMR may therefore be preferred for risk stratification and management of this high-risk patient group.

MR myocardial perfusion imaging

Contrast material-enhanced myocardial perfusion imaging by using cardiac magnetic resonance (MR) imaging has, during the past decade, evolved into an accurate technique for diagnosing coronary artery disease, with excellent prognostic value. Advantages such as high spatial resolution; absence of ionizing radiation; and the ease of routine integration with an assessment of viability, wall motion, and cardiac anatomy are readily recognized. The need for training and technical expertise and the regulatory hurdles, which might prevent vendors from marketing cardiac MR perfusion imaging, may have hampered its progress. The current review considers both the technical developments and the clinical experience with cardiac MR perfusion imaging, which hopefully demonstrates that it has long passed the stage of a research technique. In fact, cardiac MR perfusion imaging is moving beyond traditional indications such as diagnosis of coronary disease to novel applications such as in congenital heart disease, where the imperatives of avoidance of ionizing radiation and achievement of high spatial resolution are of high priority. More wide use of cardiac MR perfusion imaging, and novel applications thereof, are aided by the progress in parallel imaging, high-field-strength cardiac MR imaging, and other technical advances discussed in this review.

Cost-effectiveness of cardiovascular magnetic resonance and single-photon emission computed tomography for diagnosis of coronary artery disease in Germany

BACKGROUND

Recent studies have demonstrated a superior diagnostic accuracy of cardiovascular magnetic resonance (CMR) for the detection of coronary artery disease (CAD). We aimed to determine the comparative cost-effectiveness of CMR versus single-photon emission computed tomography (SPECT).

METHODS

Based on Bayes' theorem, a mathematical model was developed to compare the cost-effectiveness and utility of CMR with SPECT in patients with suspected CAD. Invasive coronary angiography served as the standard of reference. Effectiveness was defined as the accurate detection of CAD, and utility as the number of quality-adjusted life-years (QALYs) gained. Model input parameters were derived from the literature, and the cost analysis was conducted from a German health care payer's perspective. Extensive sensitivity analyses were performed.

RESULTS

Reimbursement fees represented only a minor fraction of the total costs incurred by a diagnostic strategy. Increases in the prevalence of CAD were generally associated with improved cost-effectiveness and decreased costs per utility unit (ΔQALY). By comparison, CMR was consistently more cost-effective than SPECT, and showed lower costs per QALY gained. Given a CAD prevalence of 0.50, CMR was associated with total costs of €6,120 for one patient correctly diagnosed as having CAD and with €2,246 per ΔQALY gained versus €7,065 and €2,931 for SPECT, respectively. Above a threshold value of CAD prevalence of 0.60, proceeding directly to invasive angiography was the most cost-effective approach.

CONCLUSIONS

In patients with low to intermediate CAD probabilities, CMR is more cost-effective than SPECT. Moreover, lower costs per utility unit indicate a superior clinical utility of CMR.

Rapid ungated myocardial perfusion cardiovascular magnetic resonance: preliminary diagnostic accuracy

BACKGROUND

Myocardial perfusion cardiovascular magnetic resonance (CMR) is a well-established method for detection of ischemic heart disease. However, ECG gating problems can result in image degradation and non-diagnostic scans, particularly in patients with arrhythmias.

METHODS

A turboFLASH saturation recovery pulse sequence was used without any ECG triggering. One saturation pulse followed by 4-5 slices of undersampled radial k-space images was acquired rapidly, on the order of 40-50 msec per image. The acquisition of the set of 4-5 slices was continuously repeated approximately 4 times per second. An iterative constrained reconstruction method was used to reconstruct the ungated images. The ungated perfusion images were post-processed into three different sets of images (ungated, self-gated to near systole, and self-gated to near diastole). To test the ungated approach and compare the different processing methods, 8 patients scheduled for coronary angiography underwent stress and rest perfusion imaging with the ungated acquisition. Six patients had a history of atrial fibrillation (AF). Three blinded readers assessed image quality and presence/absence of disease.

RESULTS

All 8 subjects successfully completed the perfusion CMR protocol and 7/8 underwent coronary angiography. Three patients were in atrial fibrillation during CMR. Overall, the CMR images were of high quality as assessed by the three readers. There was little difference in image quality between patients in AF compared to those in sinus rhythm (3.6±0.7 vs. 3.3±0.5). Stress/rest perfusion imaging showed normal perfusion in 4 patients, fixed perfusion defects in 2 patients, and reversible perfusion defects in 2 patients, corresponding with angiographic results. Pooled results from the independent readers gave a sensitivity of 0.92 (CI 0.65-0.99) and specificity of 0.92 (CI 0.65-0.99) for the detection of coronary artery disease using ungated perfusion imaging. The same sensitivity, and a specificity of 1 (CI 0.76-1), was achieved when the images were self-gated after acquisition into near systole or near diastole.

CONCLUSIONS

Ungated radial dynamic perfusion CMR can give high quality imaging in patients in sinus rhythm and during atrial fibrillation. In this small cohort, high diagnostic accuracy was possible with this rapid perfusion imaging sequence. An ungated approach simplifies the acquisition and could expand the role of perfusion CMR to include patients with arrhythmia and those with gating problems.

CT fractional flow reserve: the next level in non-invasive cardiac imaging

The haemodynamic effect of a coronary artery stenosis is a better predictor of prognosis than anatomical lumen obstruction. Until recently, no individual non-invasive test could provide both accurate coronary anatomy and lesion-specific myocardial ischaemia. However, computer tomography (CT) fractional flow reserve, which can be calculated from a standard CT coronary angiogram, was recently demonstrated to accurately detect and rule out the haemodynamic significance of individual coronary artery stenoses.

Cardiovascular magnetic resonance imaging in ischemic heart disease

Ischemic heart disease is the most frequent etiology for cardiovascular morbidity and mortality. Early detection and accurate monitoring are essential to guide optimal patient treatment and assess the individual's prognosis. In this regard, cardiovascular magnetic resonance (CMR), which entered the arena of noninvasive cardiovascular imaging over the past two decades, became a very important imaging modality, mainly due to its unique versatility. CMR has proven accuracy and is a robust technique for the assessment of myocardial function both at rest and during stress. It also allows stress perfusion analysis with high spatial and temporal resolution, and provides a means by which to differentiate tissue such as distinguishing between reversibly and irreversibly injured myocardium. In particular, the latter aspect is a unique benefit of CMR compared with other noninvasive imaging modalities such as echocardiography and nuclear medicine, and provides novel information concerning the presence, size, transmurality, and prognosis of myocardial infarction. This article is intended to provide the reader with an overview of the various applications of CMR for the assessment of ischemic heart disease from a clinical perspective.

Contrast-enhanced cardiac magnetic resonance imaging

Cardiac magnetic resonance (CMR) imaging has significantly evolved in the past decade and is well established in the evaluation of coronary artery disease (CAD). The evaluation of cardiac anatomy and contractility by high-resolution CMR can be improved by using intravenous administration of gadolinium-based contrast agents. Delayed enhancement CMR imaging has become the gold standard for quantification of myocardial viability in CAD. Contrast-enhanced CMR imaging may circumvent the need for endomyocardial biopsy or localize the involved regions, thereby improving the diagnostic yield of this invasive procedure. The application of contrast-enhanced CMR as an advanced imaging technique for ischemic and nonischemic diseases is reviewed.

Superior diagnostic performance of perfusion-cardiovascular magnetic resonance versus SPECT to detect coronary artery disease: The secondary endpoints of the multicenter multivendor MR-IMPACT II (Magnetic Resonance Imaging for Myocardial Perfusion Assessment in Coronary Artery Disease Trial)

BACKGROUND

Perfusion-cardiovascular magnetic resonance (CMR) is generally accepted as an alternative to SPECT to assess myocardial ischemia non-invasively. However its performance vs gated-SPECT and in sub-populations is not fully established. The goal was to compare in a multicenter setting the diagnostic performance of perfusion-CMR and gated-SPECT for the detection of CAD in various populations using conventional x-ray coronary angiography (CXA) as the standard of reference.

METHODS

In 33 centers (in US and Europe) 533 patients, eligible for CXA or SPECT, were enrolled in this multivendor trial. SPECT and CXA were performed within 4 weeks before or after CMR in all patients. Prevalence of CAD in the sample was 49% and 515 patients received MR contrast medium. Drop-out rates for CMR and SPECT were 5.6% and 3.7%, respectively (ns). The study was powered for the primary endpoint of non-inferiority of CMR vs SPECT for both, sensitivity and specificity for the detection of CAD (using a single-threshold reading), the results for the primary endpoint were reported elsewhere. In this article secondary endpoints are presented, i.e. the diagnostic performance of CMR versus SPECT in subpopulations such as multi-vessel disease (MVD), in men, in women, and in patients without prior myocardial infarction (MI). For diagnostic performance assessment the area under the receiver-operator-characteristics-curve (AUC) was calculated. Readers were blinded versus clinical data, CXA, and imaging results.

RESULTS

The diagnostic performance (= area under ROC = AUC) of CMR was superior to SPECT (p = 0.0004, n = 425) and to gated-SPECT (p = 0.018, n = 253). CMR performed better than SPECT in MVD (p = 0.003 vs all SPECT, p = 0.04 vs gated-SPECT), in men (p = 0.004, n = 313) and in women (p = 0.03, n = 112) as well as in the non-infarct patients (p = 0.005, n = 186 in 1-3 vessel disease and p = 0.015, n = 140 in MVD).

CONCLUSION

In this large multicenter, multivendor study the diagnostic performance of perfusion-CMR to detect CAD was superior to perfusion SPECT in the entire population and in sub-groups. Perfusion-CMR can be recommended as an alternative for SPECT imaging.

TRIAL REGISTRATION

ClinicalTrials.gov, Identifier: NCT00977093.

Quantification of myocardial perfusion reserve at 1.5 and 3.0 Tesla: a comparison to fractional flow reserve

The objective of this study was to compare quantitative analysis of cardiac magnetic resonance (CMR) perfusion at 1.5 and 3 T against fractional flow reserve (FFR) as measured invasively. FFR is considered by many investigators to be a reliable standard to determine hemodynamically significant coronary artery stenoses. Quantitative 1.5 and 3 T CMR is capable to noninvasively determine myocardial perfusion reserve, but have not been compared against each other and validated against FFR as standard reference. Patients with suspected or known coronary artery disease (CAD) underwent CMR at at both field strengths, 1.5 and 3 T, and FFR. 34 patients were included into the study. Quantitative myocardial perfusion reserve was calculated in 544 myocardial segments at 1.5 and 3 T, respectively. FFR was measured in 109 coronary arteries. FFR ≤ 0.8 was regarded relevant. Reduced FFR (≤0.8) was found in 38 coronary arteries (19 LAD, 8 LCX and 11 RCA). Receiver operator curve analysis yielded higher area under the curve for 3 T CMR in comparison to 1.5 T CMR (0.963 vs. 0.645, p < 0.001) resulting in higher sensitivity (90.5 vs. 61.9 %) and specificity (100 vs. 76.9 %). Quantitative analysis of CMR myocardial perfusion reserve at 1.5 and 3 T is capable to detect hemodynamic significance of coronary artery stenoses. Diagnostic accuracy at 3 T is to be superior to 1.5 T.

MR-IMPACT II: Magnetic Resonance Imaging for Myocardial Perfusion Assessment in Coronary artery disease Trial: perfusion-cardiac magnetic resonance vs. single-photon emission computed tomography for the detection of coronary artery disease: a comparative multicentre, multivendor trial

AIMS

Perfusion-cardiac magnetic resonance (CMR) has emerged as a potential alternative to single-photon emission computed tomography (SPECT) to assess myocardial ischaemia non-invasively. The goal was to compare the diagnostic performance of perfusion-CMR and SPECT for the detection of coronary artery disease (CAD) using conventional X-ray coronary angiography (CXA) as the reference standard.

METHODS AND RESULTS

In this multivendor trial, 533 patients, eligible for CXA or SPECT, were enrolled in 33 centres (USA and Europe) with 515 patients receiving MR contrast medium. Single-photon emission computed tomography and CXA were performed within 4 weeks before or after CMR in all patients. The prevalence of CAD in the sample was 49%. Drop-out rates for CMR and SPECT were 5.6 and 3.7%, respectively (P = 0.21). The primary endpoint was non-inferiority of CMR vs. SPECT for both sensitivity and specificity for the detection of CAD. Readers were blinded vs. clinical data, CXA, and imaging results. As a secondary endpoint, the safety profile of the CMR examination was evaluated. For CMR and SPECT, the sensitivity scores were 0.67 and 0.59, respectively, with the lower confidence level for the difference of +0.02, indicating superiority of CMR over SPECT. The specificity scores for CMR and SPECT were 0.61 and 0.72, respectively (lower confidence level for the difference: -0.17), indicating inferiority of CMR vs. SPECT. No severe adverse events occurred in the 515 patients.

CONCLUSION

In this large multicentre, multivendor study, the sensitivity of perfusion-CMR to detect CAD was superior to SPECT, while its specificity was inferior to SPECT. Cardiac magnetic resonance is a safe alternative to SPECT to detect perfusion deficits in CAD.

Cardiovascular magnetic resonance and single-photon emission computed tomography for diagnosis of coronary heart disease (CE-MARC): a prospective trial

BACKGROUND

In patients with suspected coronary heart disease, single-photon emission computed tomography (SPECT) is the most widely used test for the assessment of myocardial ischaemia, but its diagnostic accuracy is reported to be variable and it exposes patients to ionising radiation. The aim of this study was to establish the diagnostic accuracy of a multiparametric cardiovascular magnetic resonance (CMR) protocol with x-ray coronary angiography as the reference standard, and to compare CMR with SPECT, in patients with suspected coronary heart disease.

METHODS

In this prospective trial patients with suspected angina pectoris and at least one cardiovascular risk factor were scheduled for CMR, SPECT, and invasive x-ray coronary angiography. CMR consisted of rest and adenosine stress perfusion, cine imaging, late gadolinium enhancement, and MR coronary angiography. Gated adenosine stress and rest SPECT used (99m)Tc tetrofosmin. The primary outcome was diagnostic accuracy of CMR. This trial is registered at controlled-trials.com, number ISRCTN77246133.

FINDINGS

In the 752 recruited patients, 39% had significant CHD as identified by x-ray angiography. For multiparametric CMR the sensitivity was 86·5% (95% CI 81·8-90·1), specificity 83·4% (79·5-86·7), positive predictive value 77·2%, (72·1-81·6) and negative predictive value 90·5% (87·1-93·0). The sensitivity of SPECT was 66·5% (95% CI 60·4-72·1), specificity 82·6% (78·5-86·1), positive predictive value 71·4% (65·3-76·9), and negative predictive value 79·1% (74·8-82·8). The sensitivity and negative predictive value of CMR and SPECT differed significantly (p<0·0001 for both) but specificity and positive predictive value did not (p=0·916 and p=0·061, respectively).

INTERPRETATION

CE-MARC is the largest, prospective, real world evaluation of CMR and has established CMR's high diagnostic accuracy in coronary heart disease and CMR's superiority over SPECT. It should be adopted more widely than at present for the investigation of coronary heart disease.

FUNDING

British Heart Foundation.

Stress cardiac magnetic resonance

PURPOSE OF REVIEW

Coronary artery disease (CAD) is associated with significant morbidity and mortality. Several noninvasive imaging techniques such as stress echocardiography, stress nuclear studies, computed tomography coronary angiography, and, most recently, stress cardiovascular magnetic resonance (CMR) have enhanced the accuracy and efficiency of evaluation of patients.

RECENT FINDINGS

The diagnostic capabilities of CMR have increased substantially over the past 20 years due to hardware and software advances. Today, CMR has a number of unique advantages over other imaging modalities - primarily because it provides a view of the entire heart without limitations from inadequate imaging windows or body habitus. Furthermore, along with stress imaging for inducible wall motion or perfusion abnormalities, CMR provides a comprehensive examination with concurrent evaluation of the ejection fraction, aorta, pericardium, and valves all without the inherent risks of radiation administration or contrast exposure.

SUMMARY

The purpose of this article is to review the current state of stress CMR for both detection of significant disease and the prognostication of future cardiac events. Clinical data will demonstrate that stress CMR is accurate, with detection in a broad population of patients similar to or better than reported using other noninvasive stress imaging techniques. Moreover, patients with a normal adenosine stress CMR scan have an excellent prognosis on follow-up with no adverse cardiovascular outcomes. Thus, CMR perfusion stress testing has been deemed appropriate for the evaluation of chest pain syndromes in patients with intermediate probability of coronary artery disease (CAD) and for ascertaining the physiologic significance of indeterminate coronary artery lesions.

Assessment of myocardial ischemia with cardiovascular magnetic resonance

Assessment of myocardial ischemia in symptomatic patients remains a common and challenging clinical situation faced by physicians. Risk stratification by presence of ischemia provides important utility for both prognostic assessment and management. Unfortunately, current noninvasive modalities possess numerous limitations and have limited prognostic capacity. More recently, ischemia assessment by cardiovascular magnetic resonance (CMR) has been shown to be a safe, available, and potentially cost-effective alternative with both high diagnostic and prognostic accuracy. Cardiovascular magnetic resonance has numerous advantages over other noninvasive methods, including high temporal and spatial resolution, relatively few contraindications, and absence of ionizing radiation. Furthermore, studies assessing the clinical utility and cost effectiveness of CMR in the short-term setting for patients without evidence of an acute myocardial infarction have also demonstrated favorable results. This review will cover techniques of ischemia assessment with CMR by both stress-induced wall motion abnormalities as well as myocardial perfusion imaging. The diagnostic and prognostic performance studies will also be reviewed, and the use of CMR for ischemia assessment will be compared with other commonly used noninvasive modalities.

Diagnostic accuracy of adenosine stress cardiovascular magnetic resonance following acute ST-segment elevation myocardial infarction post primary angioplasty

BACKGROUND

Adenosine stress cardiovascular magnetic resonance (CMR) has been proven an effective tool in detection of reversible ischemia. Limited evidence is available regarding its accuracy in the setting of acute coronary syndromes, particularly in evaluating the significance of non-culprit vessel ischaemia. Adenosine stress CMR and recent advances in semi-quantitative image analysis may prove effective in this area. We sought to determine the diagnostic accuracy of semi-quantitative versus visual assessment of adenosine stress CMR in detecting ischemia in non-culprit territory vessels early after primary percutaneous coronary intervention (PCI) for ST-segment elevation myocardial infarction (STEMI).

METHODS

Patients were prospectively enrolled in a CMR imaging protocol with rest and adenosine stress perfusion, viability and cardiac functional assessment 3 days after successful primary-PCI for STEMI. Three short axis slices each divided into 6 segments on first pass adenosine perfusion were visually and semi-quantitatively analysed. Diagnostic accuracy of both methods was compared with non-culprit territory vessels utilising quantitative coronary angiography (QCA) with significant stenosis defined as ≥ 70%.

RESULTS

Fifty patients (age 59 ± 12 years) admitted with STEMI were evaluated. All subjects tolerated the adenosine stress CMR imaging protocol with no significant complications. The cohort consisted of 41% anterior and 59% non anterior infarctions. There were a total of 100 non-culprit territory vessels, identified on QCA. The diagnostic accuracy of semi-quantitative analysis was 96% with sensitivity of 99%, specificity of 67%, positive predictive value (PPV) of 97% and negative predictive value (NPV) of 86%. Visual analysis had a diagnostic accuracy of 93% with sensitivity of 96%, specificity of 50%, PPV of 97% and NPV of 43%.

CONCLUSION

Adenosine stress CMR allows accurate detection of non-culprit territory stenosis in patients successfully treated with primary-PCI post STEMI. Semi-quantitative analysis may be required for improved accuracy. Larger studies are however required to demonstrate that early detection of non-culprit vessel ischemia in the post STEMI setting provides a meaningful test to guide clinical decision making and ultimately improved patient outcomes.

Pharmacological stress cardiovascular magnetic resonance

Over the past decade, cardiovascular magnetic resonance (CMR) has evolved into a cardiac stress testing modality that can be used to diagnose myocardial ischemia using intravenous dobutamine or vasodilator perfusion agents such as adenosine or dipyridamole. Because CMR produces high-resolution tomographic images of the human heart in multiple imaging planes, it has become a highly attractive noninvasive testing modality for those suspected of having myocardial ischemia. The purpose of this article is to review the clinical, diagnostic, and prognostic utility of stress CMR testing for patients with (or suspected of having) coronary artery disease.