Albert C. van Rossum

MR-IMPACT: comparison of perfusion-cardiac magnetic resonance with single-photon emission computed tomography for the detection of coronary artery disease in a multicentre, multivendor, randomized trial.

AIMS To determine in a multicentre, multivendor trial the diagnostic performance for perfusion-cardiac magnetic resonance (perfusion-CMR) in comparison with coronary X-ray angiography (CXA) and single-photon emission computed tomography (SPECT). METHODS AND RESULTS Of 241 eligible patients from 18 centres, 234 were randomly dosed with 0.01, 0.025, 0.05, 0.075, or 0.1 mmol/kg Gd-DTPA-BMA (Omniscantrade mark, GE-Healthcare) per stress (0.42 mg/kg adenosine) and rest perfusion study. Coronary artery disease (CAD) was defined as diameter stenosis > or =50% on quantitative CXA. Five CMR and eight SPECT studies (of 225 complete studies) were excluded from analyses due to inadequate quality (three blinded readers scored per modality). The comparison of CMR vs. SPECT was based on receiver operating characteristic (ROC) analysis. Perfusion-CMR at the optimal CM dose (0.1 mmol/kg) had similar performance as SPECT, if only the SPECT studies of the 42 patients with this dose were considered [area under ROC curve (AUC): 0.86 +/- 0.06 vs. 0.75 +/- 0.09 for SPECT, P = 0.12]; however, diagnostic performance of perfusion-CMR was better vs. the entire SPECT population (AUC: 0.67 +/- 0.05, n = 212, P = 0.013). CONCLUSIONS In this multicentre, multivendor trial, ROC analyses suggest perfusion-CMR as a valuable alternative to SPECT for CAD detection showing equal performance in the head-to-head comparison. Comparing perfusion-CMR with the entire SPECT population suggests CMR superiority over SPECT, which warrants further evaluation in larger trials.

Delayed contrast-enhanced magnetic resonance imaging for the prediction of regional functional improvement after acute myocardial infarction.

OBJECTIVES We evaluated whether delayed contrast-enhanced magnetic resonance imaging (DCE-MRI) using an extracellular contrast agent could predict improvement of dysfunctional but viable myocardium after acute reperfused myocardial infarction (MI). BACKGROUND The transmural extent of hyperenhancement at DCE-MRI has been related to improvement of function in reperfused MI. However, evidence is still limited, and earlier reports have produced conflicting results regarding the significance of contrast patterns after infarction. METHODS Thirty patients (mean age 59 +/- 11 years, 27 males) underwent cine MRI and DCE-MRI 7 +/- 3 days after a first reperfused acute MI and follow-up cine MRI at 13 +/- 3 weeks. Segmental wall thickening and segmental extent of hyperenhancement were scored in 1,689 segments. RESULTS Of 500 dysfunctional segments, 273 (55%) improved at follow-up. There was no difference in likelihood of improvement or complete functional recovery between segments with 0% and 1% to 25% hyperenhancement. The likelihood of improvement of segments without hyperenhancement was 2.9, 14.3, and 20 times higher than that of segments with 26% to 50%, 51% to 75%, and >75% hyperenhancement, respectively (p < 0.001). The likelihood of complete functional recovery of segments without hyperenhancement was 3.8, 11.1, and 50 times higher than that of segments with 26% to 50%, 51% to 75%, and >75% hyperenhancement, respectively (p < 0.001). CONCLUSIONS In patients with recent reperfused MI, functional improvement of stunned myocardium is predicted by DCE-MRI.

Functional recovery after acute myocardial infarction: comparison between angiography, electrocardiography, and cardiovascular magnetic resonance measures of microvascular injury.

OBJECTIVES We examined the relation between angiographic, electrocardiographic, and gadolinium-enhanced cardiovascular magnetic resonance (CMR) characteristics of microvascular obstruction (MVO), and their predictive value on functional recovery after acute myocardial infarction (AMI). BACKGROUND Microvascular obstruction on CMR has been shown to predict left ventricular (LV) remodeling, but it is not well known how it compares with commonly used criteria of microvascular injury, and earlier reports have produced conflicting results on the significance and extent of MVO. METHODS Thrombolysis In Myocardial Infarction (TIMI) flow grade, myocardial blush grade (MBG), and ST-segment resolution were assessed in 60 patients with AMI treated with primary stenting. Cardiovascular magnetic resonance was performed between 2 and 9 days after revascularization to determine early MVO on first-pass perfusion imaging, late MVO on late gadolinium-enhanced imaging, and infarct size and transmural extent. Cine imaging was used to determine LV volumes and global and regional function at baseline and 4-month follow-up. RESULTS Early and late MVO were both related to incomplete ST-segment resolution (p = 0.002 and p = 0.01, respectively), but not to TIMI flow grade and MBG. Of all angiographic, electrocardiographic, and CMR variables, late MVO was the strongest parameter to predict changes in end-diastolic volume (beta = 0.53; p = 0.001), end-systolic volume (beta = 8.67; p = 0.001), and ejection fraction (beta = 3.94; p = 0.006) at follow-up. Regional analysis showed that late MVO had incremental diagnostic value to transmural extent of infarction (odds ratio: 0.18; p < 0.0001). CONCLUSIONS In patients after revascularized AMI, late MVO proved a more powerful predictor of global and regional functional recovery than all of the other characteristics, including transmural extent of infarction.

Intracoronary infusion of mononuclear cells from bone marrow or peripheral blood compared with standard therapy in patients after acute myocardial infarction treated by primary percutaneous coronary intervention: results of the randomized controlled HEBE trial

AIMS Previous trials that investigated cell therapy as an adjunctive therapy after acute myocardial infarction (AMI) have shown conflicting results. We designed a randomized controlled trial to determine the effect of intracoronary infusion of mononuclear cells from bone marrow (BM) or peripheral blood in patients with AMI. METHODS AND RESULTS In a multicentre trial, 200 patients with large first AMI treated with primary percutaneous coronary intervention were randomly assigned to either intracoronary infusion of mononuclear BM cells (n = 69), mononuclear peripheral blood cells (n = 66), or standard therapy (without placebo infusion) (n = 65). Mononuclear cells were delivered intracoronary between 3 and 8 days after AMI. Regional and global left ventricular myocardial function and volumes were assessed by magnetic resonance imaging before randomization and at 4 months, and clinical events were reported. The primary endpoint of the percentage of dysfunctional left ventricular segments that improved during follow-up did not differ significantly between either of the treatment groups and control: 38.6 ± 24.7% in the BM group, 36.8 ± 20.9% in the peripheral blood group, and 42.4 ± 18.7% in the control group (P = 0.33 and P = 0.14). Improvement of left ventricular ejection fraction was 3.8 ± 7.4% in the BM group, 4.2 ± 6.2% in the peripheral blood group when compared with 4.0 ± 5.8% in the control group (P = 0.94 and P = 0.90). Furthermore, the three groups did not differ significantly in changes in left ventricular volumes, mass, and infarct size and had similar rates of clinical events. CONCLUSION Intracoronary infusion of mononuclear cells from BM or peripheral blood following AMI does not improve regional or global systolic myocardial function in the HEBE trial. REGISTRATION The Netherlands Trial Register #NTR166 (www.trialregister.nl) and the International Standard Randomised Controlled Trial, #ISRCTN95796863 (http://isrctn.org).

Clinical indications for cardiovascular magnetic resonance (CMR): Consensus Panel report

Cardiovascular magnetic resonance (CMR) is established in clinical practice for the diagnosis and management of diseases of the cardiovascular system. However, current guidelines for when this technique should be employed in clinical practice have not been revised since a Task Force report of 1998. Considerable technical and practice advances have been made in the intervening years and the level of interest from clinicians in this field is at an unprecedented level. Therefore the aim of this report from a Consensus Panel of established experts in the field of CMR is to update these guidelines. As CMR is a multi-disciplinary technique with international interest, the Consensus Panel was composed of European and American cardiologists and radiologists with major input from members with additional established expertise in paediatric cardiology, nuclear cardiology, magnetic resonance physics and spectroscopy, as well as health economics. The Consensus Panel was originated, approved and funded in its activities by the Working Group on CMR of the European Society of Cardiology and the Society for Cardiovascular Magnetic Resonance. The Consensus Panel recommendations are based on evidence compiled from the literature and expert experience. If there is insufficient evidence in the literature, this is indicated in the report but usually no recommen-

Myocardial viability in chronic ischemic heart disease: Comparison of contrast-enhanced magnetic resonance imaging with 18F-fluorodeoxyglucose positron emission tomography

OBJECTIVES We sought to compare contrast-enhanced magnetic resonance imaging (ceMRI) with nuclear metabolic imaging for the assessment of myocardial viability in patients with chronic ischemic heart disease and left ventricular (LV) dysfunction. BACKGROUND Contrast-enhanced MRI has been shown to identify scar tissue in ischemically damaged myocardium. METHODS Twenty-six patients with chronic coronary artery disease and LV dysfunction (mean ejection fraction 31 +/- 11%) underwent (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET), technetium-99m tetrofosmin single-photon emission computed tomography (SPECT), and ceMRI. In a 17-segment model, the segmental extent of hyperenhancement (SEH) by ceMRI, defined as the relative amount of contrast-enhanced tissue per myocardial segment, was compared with segmental FDG and tetrofosmin uptake by PET and SPECT. RESULTS In severely dysfunctional segments (n = 165), SEH was 9 +/- 14%, 33 +/- 25% (p < 0.05), and 80 +/- 23% (p < 0.05) in segments with normal metabolism/perfusion, metabolism/perfusion mismatch, and matched defects, respectively. Segmental glucose uptake by PET was inversely correlated to SEH (r = -0.86, p < 0.001). By receiver operator characteristic curve analysis, the area under the curve was 0.95 for the differentiation between viable and non-viable segments. At a cutoff value of 37%, SEH optimally differentiated viable from non-viable segments defined by PET. Using this threshold, the sensitivity and specificity of ceMRI to detect non-viable myocardium as defined by PET were 96% and 84%, respectively. CONCLUSIONS Contrast-enhanced MRI allows assessment of myocardial viability with a high accuracy, compared with FDG-PET, in patients with chronic ischemic heart disease and LV dysfunction.

Quantification of regional contractile function after infarction: strain analysis superior to wall thickening analysis in discriminating infarct from remote myocardium

OBJECTIVES Using two-dimensional wall thickening (WT) (expressed as percentage) and strain analysis, regional contractile myocardial function was quantified and compared in 13 control subjects and 13 patients with a first myocardial infarction (MI). The findings in the patient group were related to global ventricular function and infarct size. BACKGROUND In patients with coronary artery disease, regions with dysfunctional myocardium cannot be differentiated easily from regions with normal function by planar WT analysis. Physiologic factors, in combination with limitations of conventional imaging techniques, affect the calculation of WT. Quantitative assessment of contractile function by magnetic resonance (MR) tissue tagging and strain analysis may be less affected by these factors. METHODS Two-dimensional regional WT and strain were calculated in three short-axis MR cine and tagged images, respectively. Left ventricular volumes and ejection fraction (EF) were obtained from a series of contiguous short-axis cine images. RESULTS In patients with infarct-related ventricles, WT and strain analysis both revealed reduced myocardial function, as compared with control subjects (p < 0.005 and p < 0.001, respectively). However, WT analysis yielded no significant regional differences in function between infarct-related and remote myocardium (p = 0.064), whereas strain analysis did (p < 0.005). For detecting dysfunctional myocardium of electrocardiographically and angiographically defined infarct areas, WT analysis had a sensitivity of 69% and a specificity of 92%, whereas strain analysis demonstrated a sensitivity of 92% and a specificity of 99%. The EF correlated with WT (r = 0.76, p < 0.005) and strain (r = 0.89, p < 0.001). CONCLUSIONS Two-dimensional strain analysis is more accurate than planar WT analysis in discriminating dysfunctional from functional myocardium, and it provides a strong correlation between regional myocardial and global ventricular function.

EuroCMR (European Cardiovascular Magnetic Resonance) Registry: Results of the German Pilot Phase

OBJECTIVES During its German pilot phase, the EuroCMR (European Cardiovascular Magnetic Resonance) registry sought to evaluate indications, image quality, safety, and impact on patient management of routine CMR. BACKGROUND CMR has a broad range of applications and is increasingly used in clinical practice. METHODS This was a multicenter registry with consecutive enrollment of patients in 20 German centers. RESULTS A total of 11,040 consecutive patients were enrolled. Eighty-eight percent of patients received gadolinium-based contrast agents. Twenty-one percent underwent adenosine perfusion, and 11% high-dose dobutamine-stress CMR. The most important indications were workup of myocarditis/cardiomyopathies (32%), risk stratification in suspected coronary artery disease/ischemia (31%), as well as assessment of viability (15%). Image quality was good in 90.1%, moderate in 8.1%, and inadequate in 1.8% of cases. Severe complications occurred in 0.05%, and were all associated with stress testing. No patient died during or due to CMR. In nearly two-thirds of patients, CMR findings impacted patient management. Importantly, in 16% of cases the final diagnosis based on CMR was different from the diagnosis before CMR, leading to a complete change in management. In more than 86% of cases, CMR was capable of satisfying all imaging needs so that no further imaging was required. CONCLUSIONS CMR is frequently performed in clinical practice in many participating centers. The most important indications are workup of myocarditis/cardiomyopathies, risk stratification in suspected coronary artery disease/ischemia, and assessment of viability. CMR imaging as used in the centers of the pilot registry is a safe procedure, has diagnostic image quality in 98% of cases, and its results have strong impact on patient management.

Early Onset and Progression of Left Ventricular Remodeling After Alcohol Septal Ablation in Hypertrophic Obstructive Cardiomyopathy

Background—Alcohol septal ablation (ASA) reduces left ventricular outflow tract (LVOT) pressure gradient in patients with hypertrophic obstructive cardiomyopathy (HOCM), which leads to left ventricular remodeling. We sought to describe the early to midterm changes and modulating factors of the remodeling process using cardiac MRI (CMR). Methods and Results—CMR was performed at baseline and 1 and 6 months after ASA in 29 patients with HOCM (age 52±16 years). Contrast-enhanced CMR showed no infarct-related hyperenhancement outside the target septal area. Septal mass decreased from 75±23 g at baseline to 68±22 and 58±19 g (P<0.001) at 1- and 6-month follow-up, respectively. Remote, nonseptal mass decreased from 141±41 to 132±40 and 111±27 g (P<0.001), respectively. Analysis of temporal trends revealed that septal mass reduction was positively associated with contrast-enhanced infarct size and transmural or left-sided septal infarct location at both 1 and 6 months. Remote mass reduction was associated with infarct location at 6 months but not with contrast-enhanced infarct size. By linear regression analysis, percentage remote mass reduction correlated significantly with LVOT gradient reduction at 6-month follow-up (P=0.03). Conclusions—Left ventricular remodeling after ASA occurs early and progresses on midterm follow-up, modulated by CMR infarct size and location. Remote mass reduction is associated with infarct location and correlates with reduction of the LVOT pressure gradient. Thus, myocardial hypertrophy in HOCM is, at least in part, afterload dependent and reversible and is not exclusively caused by the genetic disorder.

Left ventricular torsion: an expanding role in the analysis of myocardial dysfunction.

During left ventricular (LV) torsion, the base rotates in an overall clockwise direction and the apex rotates in a counterclockwise direction when viewed from apex to base. LV torsion is followed by rapid untwisting, which contributes to ventricular filling. Because LV torsion is directly related to fiber orientation, it might depict subclinical abnormalities in heart function. Recently, ultrasound speckle tracking was introduced for quantification of LV torsion. This fast, widely available technique may contribute to a more rapid introduction of LV torsion as a clinical tool for detection of myocardial dysfunction. However, knowledge of the exact function and structure of the heart is fundamental for understanding the value of LV torsion. LV torsion has been investigated with different measurement methods during the past 2 decades, using cardiac magnetic resonance as the gold standard. The results obtained over the years are helpful for developing a standardized method to quantify LV torsion and have facilitated the interpretation and value of LV torsion before it can be used as a clinical tool.