Head to head comparison between perfusion and function during accelerated high-dose dipyridamole magnetic resonance stress for the detection of coronary artery disease

Cardiovascular Disease from Pathophysiology to Risk Estimation: Is Inflammation Estimated through Perivascular Attenuation on Computed Tomography the Key?

(1) Background: Systemic inflammation stands as a well-established risk factor for ischemic cardiovascular disease, as well as a contributing factor in the development of cardiac arrhythmias, notably atrial fibrillation. Furthermore, scientific studies have brought to light the pivotal role of localized vascular inflammation in the initiation, progression, and destabilization of coronary atherosclerotic disease. (2) Methods: We comprehensively review recent, yet robust, scientific evidence elucidating the use of perivascular adipose tissue attenuation measurement on computed tomography applied to key anatomical sites. Specifically, the investigation extends to the internal carotid artery, aorta, left atrium, and coronary arteries. (3) Conclusions: The examination of perivascular adipose tissue attenuation emerges as a non-invasive and indirect means of estimating localized perivascular inflammation. This measure is quantified in Hounsfield units, indicative of the inflammatory response elicited by dense adipose tissue near the vessel or the atrium. Particularly noteworthy is its potential utility in assessing inflammatory processes within the coronary arteries, evaluating coronary microvascular dysfunction, appraising conditions within the aorta and carotid arteries, and discerning inflammatory states within the atria, especially in patients with atrial fibrillation. The widespread applicability of perivascular adipose tissue attenuation measurement underscores its significance as a diagnostic tool with considerable potential for enhancing our understanding and management of cardiovascular diseases.

Cardiovascular magnetic resonance: What clinicians should know about safety and contraindications

Cardiovascular magnetic resonance (MR) is a multiparametric, non-ionizing, non-invasive imaging technique, which represents the imaging gold standard to study cardiac anatomy, function and tissue characterization. Faced with a wide range of clinical application, in this review we aim to provide a comprehensive guide for clinicians about MR safety, contraindications and image quality. Starting from the physical interactions of the static magnetic fields, gradients and radiofrequencies with the human body, we will describe the most common metal and electronic devices which are allowed (MR-safe), allowed under limited conditions (MR-conditional) or contraindicated (MR-unsafe). Moreover, some conditions potentially affecting image quality and patient comfort will be mentioned, including arrhythmias, claustrophobia, and poor breath-hold capacity. Finally, we will discuss the pharmacodynamics and pharmacokinetics of current gadolinium-based contrast agents, their contraindications and their potential acute and chronic adverse effects, as well as the safety issue concerning the use of vasodilating/inotropic agents in stress cardiac MR.

Role of Cardiovascular Magnetic Resonance in Ischemic Cardiomyopathy

Ischemic heart disease is the most common cause of cardiovascular morbidity and mortality. Cardiac magnetic resonance (CMR) improves on other noninvasive modalities in detection, assessment, and prognostication of ischemic heart disease. The incorporation of CMR in clinical trials allows for smaller patient samples without the sacrifice of power needed to demonstrate clinical efficacy. CMR can accurately quantify infarct acuity, size, and complications; guide therapy; and prognosticate recovery. Timing of revascularization remains the holy grail of ischemic heart disease, and viability assessment using CMR may be the missing link needed to help reduce morbidity and mortality associated with the disease.

Diagnostic performance of semi-quantitative and quantitative stress CMR perfusion analysis: a meta-analysis

BACKGROUND

Stress cardiovascular magnetic resonance (CMR) perfusion imaging is a promising modality for the evaluation of coronary artery disease (CAD) due to high spatial resolution and absence of radiation. Semi-quantitative and quantitative analysis of CMR perfusion are based on signal-intensity curves produced during the first-pass of gadolinium contrast. Multiple semi-quantitative and quantitative parameters have been introduced. Diagnostic performance of these parameters varies extensively among studies and standardized protocols are lacking. This study aims to determine the diagnostic accuracy of semi- quantitative and quantitative CMR perfusion parameters, compared to multiple reference standards.

METHOD

Pubmed, WebOfScience, and Embase were systematically searched using predefined criteria (3272 articles). A check for duplicates was performed (1967 articles). Eligibility and relevance of the articles was determined by two reviewers using pre-defined criteria. The primary data extraction was performed independently by two researchers with the use of a predefined template. Differences in extracted data were resolved by discussion between the two researchers. The quality of the included studies was assessed using the 'Quality Assessment of Diagnostic Accuracy Studies Tool' (QUADAS-2). True positives, false positives, true negatives, and false negatives were subtracted/calculated from the articles. The principal summary measures used to assess diagnostic accuracy were sensitivity, specificity, andarea under the receiver operating curve (AUC). Data was pooled according to analysis territory, reference standard and perfusion parameter.

RESULTS

Twenty-two articles were eligible based on the predefined study eligibility criteria. The pooled diagnostic accuracy for segment-, territory- and patient-based analyses showed good diagnostic performance with sensitivity of 0.88, 0.82, and 0.83, specificity of 0.72, 0.83, and 0.76 and AUC of 0.90, 0.84, and 0.87, respectively. In per territory analysis our results show similar diagnostic accuracy comparing anatomical (AUC 0.86(0.83-0.89)) and functional reference standards (AUC 0.88(0.84-0.90)). Only the per territory analysis sensitivity did not show significant heterogeneity. None of the groups showed signs of publication bias.

CONCLUSIONS

The clinical value of semi-quantitative and quantitative CMR perfusion analysis remains uncertain due to extensive inter-study heterogeneity and large differences in CMR perfusion acquisition protocols, reference standards, and methods of assessment of myocardial perfusion parameters. For wide spread implementation, standardization of CMR perfusion techniques is essential.

TRIAL REGISTRATION

CRD42016040176 .

Clinical recommendations of cardiac magnetic resonance, Part I: ischemic and valvular heart disease: a position paper of the working group 'Applicazioni della Risonanza Magnetica' of the Italian Society of Cardiology

Cardiac magnetic resonance (CMR) has emerged as a reliable and accurate diagnostic tool for the evaluation of patients with cardiac disease in several clinical settings and with proven additional diagnostic and prognostic value compared with other imaging modalities. This document has been developed by the working group on the 'application of CMR' of the Italian Society of Cardiology to provide a perspective on the current state of technical advances and clinical applications of CMR and to inform cardiologists on how to implement their clinical and diagnostic pathways with the inclusion of this technique in clinical practice. The writing committee consisted of members of the working group of the Italian Society of Cardiology and two external peer reviewers with acknowledged experience in the field 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.

Diagnostic performance of stress myocardial perfusion imaging for coronary artery disease: a systematic review and meta-analysis

Objectives

To determine and compare the diagnostic performance of stress myocardial perfusion imaging (MPI) for the diagnosis of obstructive coronary artery disease (CAD), using conventional coronary angiography (CCA) as the reference standard.

Methods

We searched Medline and Embase for literature that evaluated stress MPI for the diagnosis of obstructive CAD using magnetic resonance imaging (MRI), contrast-enhanced echocardiography (ECHO), single-photon emission computed tomography (SPECT) and positron emission tomography (PET).

Results

All pooled analyses were based on random effects models. Articles on MRI yielded a total of 2,970 patients from 28 studies, articles on ECHO yielded a sample size of 795 from 10 studies, articles on SPECT yielded 1,323 from 13 studies. For CAD defined as either at least 50 %, at least 70 % or at least 75 % lumen diameter reduction on CCA, the natural logarithms of the diagnostic odds ratio (lnDOR) for MRI (3.63; 95 % CI 3.26–4.00) was significantly higher compared to that of SPECT (2.76; 95 % CI 2.28–3.25; P = 0.006) and that of ECHO (2.83; 95 % CI 2.29–3.37; P = 0.02). There was no significant difference between the lnDOR of SPECT and ECHO (P = 0.52).

Conclusion

Our results suggest that MRI is superior for the diagnosis of obstructive CAD compared with ECHO and SPECT. ECHO and SPECT demonstrated similar diagnostic performance.

Key Points

• MRI can assess myocardial perfusion.

• MR perfusion diagnoses coronary artery disease better than echocardiography or SPECT.

• Echocardiography and SPECT have similar diagnostic performance.

• MRI can save coronary artery disease patients from more invasive tests.

• MRI and SPECT show evidence of publication bias, implying possible overestimation.

Electronic supplementary material

The online version of this article (doi:10.1007/s00330-012-2434-1) contains supplementary material, which is available to authorized users.

Assessment of left ventricular ejection fraction using the wall motion score index in cardiac magnetic resonance imaging

BACKGROUND

Left ventricular ejection fraction (LVEF) is an important indicator of left ventricular function and of the severity and prognosis of ischaemic heart disease. Assessment of regional function using the wall motion score index (WMSI) is an alternative means of evaluating left ventricular function.

AIM

We attempted to evaluate LVEF by a method using the WMSI with cardiac magnetic resonance imaging (MRI).

METHODS

One hundred and twenty-two patients referred for evaluation of heart disease had rest WMSI evaluation by cardiac MRI. The WMSI was evaluated using the 16-segment model and score proposed by the American Society of Echocardiography. In our first group of 80 patients, a correlation between WMSI and cardiac MRI LVEF was established and a regression equation was derived. This regression equation was then used in 42 consecutive patients to compare WMSI LVEF with the gold standard MRI LVEF.

RESULTS

In the first 80 patients, MRI LVEF and WMSI correlated very well (r=0.93). Similarly, in the second group of 42 patients, WMSI LVEF derived from the regression equation correlated very well with MRI LVEF (r=0.94).

CONCLUSION

An objective evaluation of LVEF can be easily made using the WMSI with cardiac MRI, which correlates very well with standard MRI planimetric methods.

The diagnostic accuracy of pharmacological stress echocardiography for the assessment of coronary artery disease: a meta-analysis

BACKGROUND

Recent American Heart Association/American College of Cardiology guidelines state that "dobutamine stress echo has substantially higher sensitivity than vasodilator stress echo for detection of coronary artery stenosis" while the European Society of Cardiology guidelines and the European Association of Echocardiography recommendations conclude that "the two tests have very similar applications". Who is right?

AIM

To evaluate the diagnostic accuracy of dobutamine versus dipyridamole stress echocardiography through an evidence-based approach.

METHODS

From PubMed search, we identified all papers with coronary angiographic verification and head-to-head comparison of dobutamine stress echo (40 mcg/kg/min +/- atropine) versus dipyridamole stress echo performed with state-of-the art protocols (either 0.84 mg/kg in 10' plus atropine, or 0.84 mg/kg in 6' without atropine). A total of 5 papers have been found. Pooled weight meta-analysis was performed.

RESULTS

the 5 analyzed papers recruited 435 patients, 299 with and 136 without angiographically assessed coronary artery disease (quantitatively assessed stenosis > 50%). Dipyridamole and dobutamine showed similar accuracy (87%, 95% confidence intervals, CI, 83-90, vs. 84%, CI, 80-88, p = 0.48), sensitivity (85%, CI 80-89, vs. 86%, CI 78-91, p = 0.81) and specificity (89%, CI 82-94 vs. 86%, CI 75-89, p = 0.15).

CONCLUSION

When state-of-the art protocols are considered, dipyridamole and dobutamine stress echo have similar accuracy, specificity and - most importantly - sensitivity for detection of CAD. European recommendations concluding that "dobutamine and vasodilators (at appropriately high doses) are equally potent ischemic stressors for inducing wall motion abnormalities in presence of a critical coronary artery stenosis" are evidence-based.

Cardiac functional stress imaging: a sequential approach with stress echo and cardiovascular magnetic resonance

AIMS

The aim of the study was to assess the feasibility and accuracy of an integrated stress imaging algorithm with echo first and second-line Cardiac Magnetic Resonance (CMR) in selected cases. Stress echo (SE) is widely used for non-invasive diagnosis of coronary artery disease (CAD), but difficult patients and ambiguous responses may be met even with top-level technology and expertise. CMR might ideally complement SE in well-selected cases with unfeasible and/or ambiguous and/or submaximal results.

METHODS AND RESULTS

152 in-hospital patients with chest pain and normal baseline function were referred for SE and coronary angiography. Of the initial population, 33 were shunted to CMR due to poor acoustic window or ambiguous or submaximal SE test. The only criterion of positivity for both techniques was the presence of regional wall motion abnormalities in at least 2 contiguous segments. Coronary angiography was performed independently of test results. Significant CAD was identified by a >50% quantitatively assessed diameter reduction in at least 1 major coronary vessel.CAD was present in 88 patients. Interpretable and diagnostic stress test were obtained in 143 patients with the sequential algorithm. The sequential (SE in 110 + CMR in 33 patients) algorithm showed a sensitivity of 76% (95% CI 66% to 85%) specificity of 87% (95% CI 76% to 95%) and accuracy of 80% (95% CI 73% to 86%).

CONCLUSION

A sequential functional stress imaging algorithm with stress echo first and stress CMR in selected cases is feasible, clinically realistic and allows an efficient, radiation-free diagnosis of CAD.