Sven Plein

Normal human left and right ventricular dimensions for MRI as assessed by turbo gradient echo and steady‐state free precession imaging sequences

To establish normal ranges of left ventricular (LV) and right ventricular (RV) dimensions as determined by the current pulse sequences in cardiac magnetic resonance imaging (MRI).

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

Summary 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 99mTc 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 CMRs high diagnostic accuracy in coronary heart disease and CMRs superiority over SPECT. It should be adopted more widely than at present for the investigation of coronary heart disease. Funding British Heart Foundation.

Standardized image interpretation and post processing in cardiovascular magnetic resonance: Society for Cardiovascular Magnetic Resonance (SCMR) Board of Trustees Task Force on Standardized Post Processing

With mounting data on its accuracy and prognostic value, cardiovascular magnetic resonance (CMR) is becoming an increasingly important diagnostic tool with growing utility in clinical routine. Given its versatility and wide range of quantitative parameters, however, agreement on specific standards for the interpretation and post-processing of CMR studies is required to ensure consistent quality and reproducibility of CMR reports. This document addresses this need by providing consensus recommendations developed by the Task Force for Post Processing of the Society for Cardiovascular MR (SCMR). The aim of the task force is to recommend requirements and standards for image interpretation and post processing enabling qualitative and quantitative evaluation of CMR images. Furthermore, pitfalls of CMR image analysis are discussed where appropriate.

Myocardial T1 mapping: Application to patients with acute and chronic myocardial infarction

T1 maps obtained with modified Look‐Locker inversion recovery (MOLLI) can be used to measure myocardial T1. We aimed to evaluate the potential of MOLLI T1 mapping for the assessment of acute and chronic myocardial infarction (MI). A total of 24 patients with a first MI underwent MRI within 8 days and after 6 months. T1 mapping was performed at baseline and at selected intervals between 2–20 min following administration of gadopentetate dimeglumine (Gd‐DTPA). Delayed‐enhancement (DE) imaging served as the reference standard for delineation of the infarct zone. On T1 maps the myocardial T1 relaxation time was assessed in hyperenhanced areas, hypoenhanced infarct cores, and remote myocardium. The planimetric size of myocardial areas with standardized T1 threshold values was measured. Acute and chronic MI exhibited different T1 changes. Precontrast threshold T1 maps detected segmental abnormalities caused by acute MI with 96% sensitivity and 91% specificity. Agreement between measurements of infarct size from T1 mapping and DE imaging was higher in chronic than in acute infarcts. Precontrast T1 maps enable the detection of acute MI. Acute and chronic MI show different patterns of T1 changes. Standardized T1 thresholds provide the potential to dichotomously identify areas of infarction. Magn Reson Med 58:34–40, 2007.

Steady-state free precession magnetic resonance imaging of the heart: comparison with segmented k-space gradient-echo imaging.

Steady‐state free precession imaging is a promising technique for cardiac magnetic resonance imaging (MRI), as it provides improved blood/myocardial contrast in shorter acquisition times compared with conventional gradient‐echo acquisition. The better contrast could improve observer agreement and automatic detection of cardiac contours for volumetric assessment of the ventricles, but measurements might differ from those obtained using conventional methods. We compared volumetric measurements, observer variabilities, and automatic contour detection between a steady‐state free precession imaging sequence (BFFE = balanced fast field echo) and segmented k‐space gradient‐echo acquisition (TFE = turbo field echo) in 41 subjects. With BFFE, significantly higher end‐diastolic and end‐systolic volumes and lower wall thickness, ventricular mass, ejection fraction, and wall motion were observed (P < 0.0001), while interobserver variabilities were lower and automatic contour detection of endocardial contours was more successful. We conclude that the improved image quality of BFFE reduces the observer‐dependence of volumetric measurements of the left ventricle (LV) but results in significantly different values in comparison to TFE measurements. J. Magn. Reson. Imaging 2001;14:230–236.

Comparison of right ventricular volume measurements between axial and short axis orientation using steady-state free precession magnetic resonance imaging.

To compare right ventricular (RV) volume measurements and their reproducibility between axial and short axis orientation acquisition techniques.

Normal values for cardiovascular magnetic resonance in adults and children

Morphological and functional parameters such as chamber size and function, aortic diameters and distensibility, flow and T1 and T2* relaxation time can be assessed and quantified by cardiovascular magnetic resonance (CMR). Knowledge of normal values for quantitative CMR is crucial to interpretation of results and to distinguish normal from disease. In this review, we present normal reference values for morphological and functional CMR parameters of the cardiovascular system based on the peer-reviewed literature and current CMR techniques and sequences.

High-Resolution Magnetic Resonance Myocardial Perfusion Imaging at 3.0-Tesla to Detect Hemodynamically Significant Coronary Stenoses as Determined by Fractional Flow Reserve

OBJECTIVES The objective of this study was to compare visual and quantitative analysis of high spatial resolution cardiac magnetic resonance (CMR) perfusion at 3.0-T against invasively determined fractional flow reserve (FFR). BACKGROUND High spatial resolution CMR myocardial perfusion imaging for the detection of coronary artery disease (CAD) has recently been proposed but requires further clinical validation. METHODS Forty-two patients (33 men, age 57.4 ± 9.6 years) with known or suspected CAD underwent rest and adenosine-stress k-space and time sensitivity encoding accelerated perfusion CMR at 3.0-T achieving in-plane spatial resolution of 1.2 × 1.2 mm(2). The FFR was measured in all vessels with >50% severity stenosis. Fractional flow reserve <0.75 was considered hemodynamically significant. Two blinded observers visually interpreted the CMR data. Separately, myocardial perfusion reserve (MPR) was estimated using Fermi-constrained deconvolution. RESULTS Of 126 coronary vessels, 52 underwent pressure wire assessment. Of these, 27 lesions had an FFR <0.75. Sensitivity and specificity of visual CMR analysis to detect stenoses at a threshold of FFR <0.75 were 0.82 and 0.94 (p < 0.0001), respectively, with an area under the receiver-operator characteristic curve of 0.92 (p < 0.0001). From quantitative analysis, the optimum MPR to detect such lesions was 1.58, with a sensitivity of 0.80, specificity of 0.89 (p < 0.0001), and area under the curve of 0.89 (p < 0.0001). CONCLUSIONS High-resolution CMR MPR at 3.0-T can be used to detect flow-limiting CAD as defined by FFR, using both visual and quantitative analyses.

Dynamic contrast-enhanced myocardial perfusion MRI accelerated with k-t sense.

In the k‐t sensitivity encoding (k‐t SENSE) method spatiotemporal data correlations are exploited to accelerate data acquisition in dynamic MRI studies. The present study demonstrates the feasibility of applying k‐t SENSE to contrast‐enhanced myocardial perfusion MRI and using the speed‐up to increase spatial resolution. At a net acceleration factor of 3.9 (k‐t factor of 5 with 11 training profiles) accurate representations of dynamic signal intensity (SI) changes were achieved in computer simulations. In vivo, 5× k‐t SENSE was compared with 2× SENSE (identical acquisition parameters except for in‐plane spatial resolution = 1.48 × 1.48 mm2 vs. 2.64 × 2.64 mm2, respectively). In 10 volunteers no differences in myocardial SI profiles were found (relative peak enhancement = 151% vs. 149.7%, maximal upslope = 12.9%/s vs. 13.3%/s for 2× SENSE and 5× k‐t SENSE, respectively, all P > 0.05). Overall image quality was similar, but endocardial dark rim artifacts were reduced with k‐t SENSE. Signal‐to‐noise ratio (SNR) in the myocardium was greater with 5× k‐t SENSE by a factor of 1.36 ± 0.23 at peak contrast enhancement with the relative yield decreasing with increasing dynamics in the object in accordance to theory. Higher nominal acceleration factors of up to 10‐fold were shown to be feasible in computer simulations and in vivo. Magn Reson Med 58:777–785, 2007.

Reperfusion haemorrhage as determined by cardiovascular MRI is a predictor of adverse left ventricular remodelling and markers of late arrhythmic risk

Background Interstitial haemorrhage due to reperfusion of severely ischaemic myocardium can be detected in vivo by T2-weighted (T2W) and T2* cardiovascular magnetic resonance (CMR). The clinical implications of myocardial haemorrhage following primary percutaneous coronary intervention (PPCI) remain undetermined. Objectives To assess whether the presence of myocardial haemorrhage influences ventricular remodelling and risk of late ventricular arrhythmia following PPCI for acute myocardial infarction (AMI). Methods Forty-eight patients with first ST-elevation AMI, treated successfully with PPCI, underwent CMR at day 2 and 3 months. Left ventricular end-diastolic volume (LVEDV), left ventricular end-systolic volume (LVESV) and left ventricular ejection fraction (LVEF) were determined from cine-CMR, infarct size and microvascular obstruction (MVO) from gadolinium-enhanced images and area at risk (AAR) from T2W CMR. Myocardial haemorrhage was defined as hypointense signal within the AAR on both T2W and T2* images. All patients had a signal-averaged electrocardiogram at 3 months. Results 30/48 (63%) patients had MVO and 12 of these showed myocardial haemorrhage. Patients with haemorrhagic myocardial infarction (MI) had significantly larger LVEDV and LVESV, lower LVEF and larger infarcts than those with non-haemorrhagic MI at baseline and at 3 months. The presence of haemorrhage was an independent predictor of adverse remodelling defined as increased LVESV on follow-up (p=0.001, OR 1.6) and prolonged filtered QRS (fQRS) on signal-averaged ECG at 3 months (p=0.020, OR 1.176). Conclusions Reperfusion haemorrhage following AMI is associated with larger infarct size, diminished myocardial salvage and lower LVEF. The presence of haemorrhage is the strongest independent predictor of adverse ventricular remodelling and is also associated with prolonged fQRS duration, which is a marker of arrhythmic risk.