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PURPOSE: To prospectively assess the effect of including or excluding endocardial trabeculae in left ventricular (LV) measurements and the reproducibility of these measurements at cine cardiovascular magnetic resonance (MR) imaging with true fast imaging with steady-state precession (FISP). MATERIALS AND METHODS: The study was approved by the local ethics committee, and each subject gave informed consent before participating. Twenty healthy subjects and 20 consecutive patients underwent 1.5-T cardiovascular MR imaging. Seven to 12 short-axis views encompassing the entire LV were acquired by using true FISP. Endocardial and epicardial contours were traced manually. The data sets in each patient were analyzed twice: with inclusion of endocardial trabeculae in the LV cavity volume and with exclusion of endocardial trabeculae from the cavity volume. On the basis of these two contour sets, the end-diastolic (ED) and end-systolic (ES) LV volumes, ejection fraction (EF), and LV mass were calculated. Additionally, interobserver and interexamination reproducibility was assessed by using Bland-Altman analysis. RESULTS: Compared with exclusion of trabeculae, inclusion of trabeculae in the LV cavity volume resulted in significantly larger ED and ES LV volumes (mean differences, 21 mL ± 11 [standard deviation] and 19 mL ± 33, respectively; P < .001) and lower EFs (mean difference, -2% ± 2; P < .001). The calculated LV mass was significantly smaller with inclusion than with exclusion of trabeculae (mean difference, -21 g ± 12; P < .001). All interobserver and interexamination limits of agreement based on inclusion of trabeculae, except those for EF measurements, were superior to those based on exclusion of trabeculae. At measurement reproducibility comparisons, differences in interobserver ED LV volume, and LV mass and interexamination LV mass were statistically significant, favoring the inclusion of trabeculae in the LV cavity volume. CONCLUSION: Trabeculae significantly affect quantifications of LV volume and mass. The superior reproducibility of LV measurements with the inclusion of endocardial trabeculae in the cavity volume favors this tracing algorithm for clinical use. © RSNA, 2005.

Purpose. To evaluate a standardized definition of delayed hyperenhancement in the analysis of contrast-enhanced cardiac magnetic resonance (ceCMR) imaging. Patients and Methods. CeCMR was performed in 15 patients with chronic ischemic heart disease. Delayed hyperenhancement was analyzed both by visual analysis by an experienced team of observers, and after thresholding the window setting of the images at 2, 3, 4, 5, and 6 SD above the mean signal intensity of remote, normal myocardium in the same slice. In each patient, total infarct size (TIS) and segmental infarct extent (SIE) were calculated. Results. TIS and SIE were 22.9 ± 12.2 mL and 32 ± 28% after visual analysis. Thresholding the window setting at 2, 3, 4, and 6 SD above signal intensity of remote caused a 40%, 31%, and 17% increase (p < 0.007) and a 7% decrease (p = NS) in TIS, and a 75%, 41%, and 16% increase and 22% decrease in SIE (p < 0.001), respectively. There was no difference between visual analysis and analysis after thresholding at 5 SD. Conclusion. Analyzing ceCMR with a standardized definition of hyperenhancement related to the signal of remote, nonenhanced myocardium may result in considerable overestimation of infarct size at the usual cut-off of 2 SD.

Background —This study investigated whether the extent of perfusion defect determined by intravenous myocardial contrast echocardiography (MCE) in patients with acute myocardial infarction (AMI) treated by primary percutaneous transluminal coronary angioplasty (PTCA) relates to coronary flow reserve (CRF) for assessment of myocardial reperfusion and is predictive for left ventricular recovery. Methods and Results —Twenty-five patients with first AMI underwent intravenous MCE with NC100100 with intermittent harmonic imaging before PTCA and after 24 hours. MCE before PTCA defined the risk region and MCE at 24 hours the “no-reflow” region. The no-reflow region divided by the risk region determined the ratio to the risk region. CFR was assessed immediately after PTCA and 24 hours later. Left ventricular wall motion score indexes were calculated before PTCA and after 4 weeks. CFR at 24 hours defined a recovery (CFR ≥1.6; n=17) and a nonrecovery group (CFR P =0.009). A ratio to the risk region of ≤50% defined an MCE reperfusion group. It was associated with improvement of CFR from 1.67±0.47 at baseline to 2.15±0.53 at 24 hours ( P P Conclusions —Intravenous MCE can be used to define perfusion defects after AMI. Assessment of microcirculation by MCE corresponds to evaluation by CFR. Serial intravenous MCE has the potential to identify patients likely to have improved left ventricular function after AMI.

Purpose: To assess the feasibility and effectiveness of rapid right ventricular pacing with a magnetic resonance (MR)-compatible pacemaker lead during MR-guided aortic valvuloplasty. Materials and Methods: This study was approved by the institutional animal research committee. Seven pigs were investigated. All experiments were performed with an interventional 1.5-T MR system. Interventions were monitored with a steady-state free precession real-time imaging sequence. An MR-compatible pacemaker lead was placed in the right ventricular apex with MR guidance before valvuloplasty. After positioning the balloon in valve position, valvuloplasty was performed with rapid right ventricular rapid pacing at a heart rate of 180 beats per minute to minimize cardiac output. Results: Positioning of the pacemaker lead with MR guidance was feasible in all swine (sensing, 6 mV +/- 1; threshold, 1 V +/- 0.5). The lead could be seen on steady-state free precession images without inducing any artifacts. Rapid right ventricular pacing was feasible in all swine, and balloon stability at the time of inflation was achieved with no balloon movement. Aortic valvuloplasty was successfully accomplished in all experiments. Conclusion: Rapid right ventricular pacing with an MR-compatible pacemaker lead is feasible and effective.

Address: 1Institut fur Herzund Kreislaufphysiologie, Heinrich-Heine-University, Dusseldorf, Germany, 2Department of Medicine, Division of Cardiology, Pulmonary Diseases and Angiology, Heinrich-Heine-University, Dusseldorf, Germany, 3University Hospital Aachen, Department of Medicine, Division of Cardiology, Pulmonary Diseases, and Vascular Medicine, Aachen, Germany and 4Department of Diagnostic Radiology, University Hospital RWTH Aachen, Aachen, Germany * Corresponding author

Background The systolic dyssynchrony index (SDI) has been introduced as a measure of mechanical dyssynchrony using three-dimensional echocardiography to select patients who may benefit from cardiac resynchronization therapy (CRT). However, three-dimensional echocardiography may be inadequate in a number of patients with suboptimal acoustic window and no single echocardiographic measure of dyssynchrony has proven to be of value in selecting patients for CRT. Thus, the aim of this study was to determine the value of cardiovascular magnetic resonance (CMR) for the assessment of the SDI in patients with reduced LV function as well as in healthy controls using semi-automatic border tracking. Methods We investigated a total of 45 patients including 35 patients (65 ± 8 years) with reduced LV function (EF 30 ± 11%) and a wide QRS complex as well as 10 control subjects (42 ± 21 years, EF 70 ± 11%). For cine imaging a standard SSFP imaging sequence was used with a temporal resolution of 40 frames per RR-interval. Quantitative analysis was performed off-line using a software prototype for semi-automatic border detection. Global volumes, ejection fraction and the SDI were calculated in each subject. SDI was compared with standard echocardiographic parameters of dyssynchrony. Results The mean SDI differed significantly between patients (14 ± 5%) and controls (5 ± 2%, p < 0.001). An exponential correlation between the EF and the SDI was observed (r = -0.84; p < 0.001). In addition, a significant association between the SDI and the standard deviation of time to peak systolic motion of 12 LV segments (Ts-SD) determined by echocardiography was observed (r = 0.66, p = 0.002). Conclusion The results of this preliminary study suggest that CMR with semi-automatic border detection may be useful for the assessment of mechanical dyssynchrony in patients with reduced LV function. No trial registration due to recruitment period between October 2004 and November 2006

Contrast-enhanced magnetic resonance (MR) imaging allows detection of nonviable myocardium. The authors compared a one-breath-hold three-dimensional inversion-recovery gradient-echo MR sequence with a multiple-breath-hold two-dimensional inversion-recovery gradient-echo MR sequence for the detection of nonviable myocardium. On the basis of a quantitative and qualitative approach, total myocardial area and contrast material-enhanced area, as well as the presence and spatial extent of hyperenhancement, were analyzed separately for each MR image obtained with each sequence in 10 patients with chronic ischemic heart disease. Findings for total myocardial area and contrast-enhanced area agreed well between the two sequences. A high level of agreement was also found for the presence of hyperenhancement (kappa = 0.84), while agreement was poor for the transmural extent of hyperenhancement (kappa = 0.32), which was attributed to the blurred appearance of the three-dimensional MR images. Findings with the one-breath-hold three-dimensional MR sequence allow assessment of nonviable myocardium with good agreement with those with the multiple-breath-hold two-dimensional MR sequence.

OBJECTIVE—To examine the influence of second harmonic imaging during dobutamine echocardiography on regional endocardial visibility, interobserver agreement in the interpretation of wall motion abnormalities, and diagnostic accuracy in patients with reduced image quality. DESIGN—Blinded comparison. SETTING—Tertiary care centre. PATIENTS—103 consecutive patients with suspected coronary artery disease and impaired transthoracic image quality (⩾ 2 segments with poor endocardial delineation). METHODS—Fundamental and second harmonic imaging were performed at each stage of a dobutamine stress echocardiography. Coronary angiography was undertaken within three weeks of dobutamine echocardiography in 75 patients. MAIN OUTCOME MEASURES—Evaluation of regional endocardial visibility (scoring from 0 = poor to 2 = good) and of segmental wall motion abnormalities for both modalities separately. A second blinded examiner analysed 70 studies to determine interobserver agreement. RESULTS—Mean (SD) visibility score for all segments was 1.2 (0.4) using fundamental imaging and 1.7 (0.2) using second harmonic imaging at rest (p

Objectives This study sought to characterize the impact of hemodialysis (HD)-induced release of hemoglobin on the bioavailability of nitric oxide (NO) and endothelial function. Background Patients on chronic HD suffer from endothelial dysfunction and a massively increased risk for cardiovascular events. Although dialysis-dependent and -independent factors are discussed, the exact mechanisms are not fully understood. Methods In 14 HD patients (56 ± 15 years of age), endothelial function was determined by measuring flow-mediated dilation (FMD) of the brachial artery using high-resolution ultrasound before and after treatment. The NO consumption activity of plasma isolated from patients before and after hemodialysis was studied with an NO-sensitive electrode. Results HD impaired FMD (3.5 ± 2.6% to 1.7 ± 1.4%, p = 0.04) without affecting brachial artery diameter (4.7 ± 0.6 mm vs. 4.4 ± 0.9 mm, p = 0.27). This was accompanied by an increase in cell-free plasma hemoglobin (196 ± 43 mg/l to 285 ± 109 mg/l, p = 0.01), which led to a decrease in the bioavailability of free NO by more than 70%. Oxidation of the released plasma ferrous hemoglobin prevented the consumption of NO. The amount of decompartmentalized hemoglobin after HD correlated inversely with the change in FMD (r = −0.65, p = 0.041). Conclusions Our data support a role of HD-induced release of hemoglobin in the pathogenesis of endothelial dysfunction in patients with end-stage renal disease. Approaches that oxidize free plasma hemoglobin may restore NO bioavailability and may have potential beneficial effects on vascular function. (Influence of Hemodialysis on Endothel-Depending Dilatation of Peripheral Arteries; NCT00764192)