Gd-BOPTA for assessment of myocardial viability on MRI: changes of T1 value and their impact on delayed enhancement.

Gadobenate (Gd-BOPTA), injected at a dose of 0.1 mmol/kg body weight, was compared with gadopentetate (Gd-DTPA), injected at a dose of 0.2 mmol/kg body weight, for delineation of myocardial infarction interindividually in two groups of 26 patients each. Delayed enhancement images were assessed subjectively for image quality, and measured for regional T1 values before, 3 min after and 25 min after the injection of each contrast agent. In the 26 patients who received Gd-BOPTA, T1 values of remote myocardium were 1,070 +/- 125 ms, 358 +/- 78 ms and 562 +/- 108 ms before, 3 min after and 25 min after injection, respectively. Infarcted myocardium values were 1,097 +/- 148 ms, 246 +/- 68 ms and 373 +/- 84 ms and left ventricular blood pool 1,238 +/- 95 ms, 194 +/- 47 ms and 373 +/- 72 ms. In the 26 patients who received Gd-DTPA, T1 values were 1,087 +/- 96 ms, 325 +/- 60 ms and 555 +/- 108 ms for remote myocardium; 1,134 +/- 109, 210 +/- 43 ms and 304 +/- 57 ms for infarcted myocardium; and 1,258 +/- 104 ms, 166 +/- 27 ms and 351 +/- 73 ms for left ventricular blood pool. Delayed enhancement image quality showing myocardial infarction was rated good (54%) and excellent (46%) after Gd-BOPTA, and good (58%) and excellent (42%) after Gd-DTPA (no significant differences). A single dose of Gd-BOPTA compared with a double dose of Gd-DTPA causes similar changes of T1 values in infarcted and remote myocardium and provides fairly similar contrast between infarcted and remote myocardium (0.64 +/- 14 versus 0.71 +/- 11) and slightly higher contrast between left ventricular blood and infarcted myocardium (0.22 +/- 17 versus 0.14 +/- 6; p < 0.05). Administration of 0.1 mmol/kg body weight Gd-BOPTA can provide similar late enhancement images compared with the standard 0.2 mmol/kg body weight dose of Gd-DTPA due to the higher T1 relaxivity associated with the former.

Feasibility and initial experience of assessment of mechanical dyssynchrony using cardiovascular magnetic resonance and semi-automatic border detection.

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.

Comparison of magnetic resonance perfusion imaging versus invasive fractional flow reserve for assessment of the hemodynamic significance of epicardial coronary artery stenosis.

This study evaluated whether first-pass perfusion cardiovascular magnetic resonance (FP-CMR) could predict the hemodynamic significance of epicardial coronary artery stenosis as defined by invasively determined fractional flow reserve at coronary angiography. In 19 patients with known coronary artery disease (CAD), the hemodynamic relevance of 22 stenoses (mean angiographic severity 73 +/- 9%) was determined using fractional flow reserve measurements (cutoff 0.75). Results were compared with a territorial index of myocardial perfusion reserve (MPR) derived from FP-CMR. In addition, 9 age-matched patients with low prevalence of risk factors and without CAD at angiography served as a control group. A cutoff of 1.5 for MPR separated hemodynamically relevant from nonrelevant stenoses with a sensitivity and specificity of 92% and 92%, respectively. The area under the receiver-operator characteristic curve was 0.97. In the patient group, territories supplied by arteries without significant stenosis (

Volumetric assessment of epicardial adipose tissue with cardiovascular magnetic resonance imaging.

OBJECTIVE: Previous studies determined the amount of epicardial fat by measuring the right ventricular epicardial fat thickness. However, it is not proven whether this one-dimensional method correlates well with the absolute amount of epicardial fat. In this prospective study, a new cardiovascular magnetic resonance imaging (CMR) method using the three-dimensional summation of slices method was introduced to assess the total amount of epicardial fat. RESEARCH METHODS AND PROCEDURES: CMR was performed in 43 patients with congestive heart failure and in 28 healthy controls. The absolute amount of epicardial fat was assessed volumetrically in consecutive short-axis views by means of the modified Simpson's rule. Additionally, the right ventricular epicardial fat thickness was measured in two different imaging planes: long-axis view (EFT-4CV) and consecutive short-axis views (EFT-SAX). RESULTS: Using the volumetric approach, patients with congestive heart failure had less epicardial fat mass than controls (51 g vs. 65 g, p=0.01). This finding was supported by EFT-SAX (2.9 mm vs. 4.3 mm, p<0.0001) but not by EFT-4CV (3.5 mm vs. 3.8 mm, p=not significant). Epicardial fat mass correlated moderately with EFT-SAX in both groups (r=0.466, p=0.012 in controls and r=0.590, p<0.0001 in patients) and with EFT-4CV in controls (r=0.387, p=0.042). There were no significant differences between EFT-4CV and EFT-SAX in controls (4.3 mm vs. 3.8 mm, p=0.240). However, in the heart failure group, EFT-4CV was significantly higher compared with EFT-SAX (3.5 mm vs. 2.9 mm, p=0.003). Interobserver variability and reproducibility were superior for the volumetric approach compared with thickness measurements. DISCUSSION: Quantitative assessment of epicardial fat mass using the CMR-based volumetric approach is feasible and yields superior reproducibility compared with conventional methods.

[Diagnosis and assessment of severity of aortic valve stenosis]. / Diagnose und Schweregradbeurteilung bei Aortenklappenstenose.

Calcific aortic valve stenosis is the most common valvular heart disease in the elderly. Although the diagnosis can often be assumed at clinical presentation, determination of the disease severity is usually not accurately possible based on patient history and physical examination alone. In the past, invasive cardiac catheterization has been the most important strategy for assessing the hemodynamic severity of aortic stenosis. Nowadays, Doppler echocardiography has largely replaced invasive catheterization in many centers, since this modality allows for a comprehensive evaluation of the morphological and functional characteristics of the stenotic valve and for assessment of the prognosis of the disease. This article summarizes the current knowledge on the evaluation of aortic stenosis severity using Doppler echocardiography.

Assessment of reversible myocardial dysfunction in chronic ischaemic heart disease: comparison of contrast-enhanced cardiovascular magnetic resonance and a combined positron emission tomography-single photon emission computed tomography imaging protocol.

AIMS: The aim of the study was to compare, in patients with chronic ischaemic cardiomyopathy, contrast-enhanced cardiovascular magnetic resonance (ce-CMR) imaging and a combined (18)F-fluorodeoxyglucose ((18)F-FDG) positron emission tomography (PET) and (99m)Tc-sestamibi single-photon emission computed tomography (SPECT) protocols for the prediction of functional recovery after revascularization, as assessed by cine CMR. METHODS AND RESULTS: Twenty-nine patients with ischaemic cardiomyopathy (ejection fraction 32 +/- 10%) were investigated with ce-CMR and PET/SPECT. For the assessment of global and regional functions, cine CMR was performed at baseline and at 6 months follow-up. For ce-CMR, the segmental extent of hyperenhancement (SEH) was quantitated, and for PET/SPECT, different viability categories were defined according to a validated quantitative protocol. Functional improvement was related to the SEH by ce-CMR, as well as to the viability categories by PET/SPECT. Sensitivity and specificity for the prediction of functional recovery at follow-up was 97 and 68% for ce-CMR and 87 and 76% for PET/SPECT. The positive predictive value was identical for both techniques (73%). However, ce-CMR achieved a higher negative predictive value (93 vs. 77%, respectively), indicating that ce-CMR may be superior to PET/SPECT for the identification of segments unlikely to recover function after revascularization. Both methods had a similar yield in the prediction of global functional improvement. CONCLUSION: ce-CMR is comparable with a PET/SPECT imaging protocol for the prediction of regional and global functional improvement after revascularization. However, ce-CMR may be superior to nuclear imaging for the identification of segments that are unlikely to recover function at follow-up.

Preliminary experience in the assessment of aortic valve calcification by ECG-gated multislice spiral computed tomography.

BACKGROUND: The aim was to correlate the degree of valvular calcification in patients with aortic stenosis determined by retrospectively electrocardiogram (ECG)-gated multislice spiral computed tomography with stenosis severity assessed by cardiac catheterization. METHODS: Prospective study on 41 patients (18 men, mean age 71+/-8 years) with aortic stenosis, who underwent four detector row multislice spiral computed tomography and cardiac catheterization. Severity of aortic stenosis was classified by cardiac catheterization. Aortic valve area, peak to peak and mean transvalvular gradients were correlated with the degree of calcification determined by multislice spiral computed tomography. Aortic valve calcification was assessed using aortic Agatston score, aortic mass score and aortic volume score. RESULTS: All measured aortic valve calcification scores were significantly higher in patients with severe aortic stenosis (n=29) than in patients with moderate (n=7) or mild aortic stenosis (n=5, p<0.001). Aortic valve calcification scores correlated significantly with aortic valve area (r=-0.49, p=0.001 for aortic mass score) and with peak to peak (r=0.68, p<0.001) and mean (r=0.60, p<0.001) transvalvular gradients. CONCLUSIONS: Severity of aortic valve calcification assessed by cardiac multislice spiral computed tomography is inversely related to aortic valve area and positively correlated with transvalvular gradients. Based on this preliminary data larger studies should be performed with echocardiography as a reference standard in order to validate this new information and its utility in the clinical management of the patient.

Assessment of myocardial viability in reperfused acute myocardial infarction using 16-slice computed tomography in comparison to magnetic resonance imaging.

OBJECTIVES: The aim of this study was to examine if contrast-enhanced multislice spiral computed tomography (MSCT) is comparable to contrast-enhanced magnetic resonance imaging (MRI) for depiction of acute myocardial infarction (MI). BACKGROUND: Delayed-enhancement MRI of MI is well established, but there are no clinical reports about MSCT for this indication. Early perfusion deficit on MSCT has been reported to correlate with the presence of MI. METHODS: A total of 28 consecutive patients (23 men; 55.9 +/- 11.4 years) with reperfused MI underwent contrast-enhanced cardiac 16-slice MSCT. Images were acquired in the arterial phase and the late phase 15 min after administration of 120 ml contrast material. Within 5 days, patients underwent MRI after administration of 0.2 mmol Gd-dimeglumine/kg/bodyweight. All examinations were completed within two weeks after MI. The area of MI was compared between the different imaging techniques using Bland-Altman method and multivariate analysis. Agreement of the contrast enhancement patterns was evaluated with a weighted kappa test. RESULTS: Mean infarct size on MRI was 31.2 +/- 22.5% per slice compared with 33.3 +/- 23.8% per slice for late-enhancement MSCT and 24.5 +/- 18.3% per slice for early-perfusion-deficit MSCT. Bland-Altman data showed a good agreement between late-enhancement MRI and late-enhancement MSCT. Contrast enhancement patterns demonstrated an excellent agreement between late-enhancement MRI and late-enhancement MSCT (kappa = 0.878). The results were worse comparing MRI and early-phase MSCT (kappa = 0.635). CONCLUSIONS: Multislice spiral computed tomography allows for the assessment of acute MI. Late-enhancement MSCT appears to be as reliable as delayed contrast-enhanced MRI in assessing infarct size and myocardial viability in acute MI.

Standardizing the definition of hyperenhancement in the quantitative assessment of infarct size and myocardial viability using delayed contrast-enhanced CMR.

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.

Sixteen-slice spiral CT versus MR imaging for the assessment of left ventricular function in acute myocardial infarction.

The aim of this study was to assess global left ventricular (LV) function and regional wall motion using retrospectively ECG-gated 16-slice computed tomography (CT) in comparison with magnetic resonance imaging (MRI). Twenty-one patients (18 male, 65.5+/-8.6 years) with acute myocardial infarction underwent multislice spiral CT (MSCT) and MRI. From manually drawn endo- and epicardial contours, LV volumes including myocardial mass, peak filling rate (PFR), peak ejection rate (PER), time to PER (TPER) and time from end-systole to PFR (TPFR) were calculated. Regional wall motion was assessed from cine loops using a 16-segment model of the left ventricle. LV function was analyzed using the Bland-Altman method, Pearson's correlation coefficient, multivariate analysis and post hoc t tests. Regional wall motion was evaluated with weighted kappa-statistics. Multivariate analysis revealed significant differences for global LV function as determined by MSCT and MRI. Post hoc t-tests showed significant differences for end-diastolic volume (EDV), PFR and TPER (P<0.05), while there was a good agreement for the LV volumes with an ejection fraction of 46.9+/-8.4% for MSCT and 46.9+/-8.9% for MRI. PER, PFR, TPER and TPFR presented a poor correlation and a wide range of scattering between MSCT and MRI. Regional wall motion scores showed a good agreement with kappa=0.791. Sixteen-slice spiral CT allows for reliable assessment of LV volumes, but is not yet suited for the evaluation of all functional parameters. Assessment of regional wall motion at rest is feasible.

Aortic valve calcification as a marker for aortic stenosis severity: assessment on 16-MDCT.

OBJECTIVE: The degree of valvular calcification in patients with aortic stenosis was determined with retrospectively ECG-gated 16-MDCT and correlated with the severity of stenosis assessed at cardiac catheterization. SUBJECTS AND METHODS: We conducted a prospective study of 72 patients (38 men and 34 women; mean age +/- SD, 69.5 +/- 8.8 years) with aortic stenosis who underwent 16-MDCT and cardiac catheterization. Aortic valve calcification was assessed using the aortic Agatston score, aortic mass score, and aortic volume score. Severity of aortic stenosis was classified at cardiac catheterization. Aortic valve area and peak-to-peak and mean transvalvular gradients were correlated with the degree of calcification determined on MDCT. RESULTS: All measured aortic valve calcification scores were significantly higher in patients with severe aortic stenosis (n = 46) than in patients with moderate (n = 15) or mild (n = 11, p < 0.001) aortic stenosis. Aortic valve calcification scores were inversely related to aortic valve area (r = -0.67, p < 0.001 for aortic mass score) and correlated significantly with peak-to-peak (r = 0.70, p < 0.001) and mean transvalvular (r = 0.72, p < 0.001) gradients. No correlation between the aortic valve calcification and the total coronary calcium scores was observed. CONCLUSION: Aortic valve calcification assessed on 16-MDCT is associated with severity of aortic stenosis. Thus, aortic valve calcification scores should be calculated routinely in all patients undergoing MDCT for assessment of coronary calcification. High aortic valve calcification scores indicate possibly severe aortic stenosis and should prompt a further functional evaluation.

Assessment of myocardial function with interactive non-breath-hold real-time MR imaging: comparison with echocardiography and breath-hold Cine MR imaging.

PURPOSE: To compare a spiral gradient-echo sequence with a radial steady-state free precession sequence and to compare these two interactive real-time cardiac magnetic resonance (MR) imaging examinations with harmonic two-dimensional echocardiography (ECHO) for the evaluation of regional myocardial function. MATERIALS AND METHODS: Electrocardiographically triggered breath-hold steady-state free precession (BH-SSFP) MR imaging was the reference standard. Thirty-five nonselected patients scheduled for routine ECHO were included. Data from corresponding two-, three-, and four-chamber long-axis views and a midventricular short-axis view were acquired with each modality. Image quality and depiction of segmental wall motion were scored semiquantitatively by using the 16-segment model of the American Society of Echocardiography. Repeated-measures analysis of variance was performed to assess differences in image quality and wall motion depiction scores among the four imaging methods. Agreement was assessed by using Cohen kappa statistics. RESULTS: Compared with the image quality achieved with BH-SSFP MR imaging, the image quality achieved with radial MR imaging was similar (nonsignificant difference), but that achieved with spiral MR imaging and ECHO was significantly inferior (P <.0001). There were no significant differences in the image quality of the long- and short-axis views between the radial and BH-SSFP sequences, while the image quality of the long-axis spiral (P <.05) and the short- and long-axis ECHO (P <.0001) views was lower than that of the BH-SSFP views. Compared with the mean wall motion score for BH-SSFP MR imaging, the mean wall motion score for radial MR imaging was not significantly different, but those for ECHO (P <.05) and spiral MR imaging (P =.0003) were significantly lower. Cohen kappa coefficients for agreement with the BH-SSFP sequence regarding wall motion scoring were 0.47 for ECHO, 0.67 for the spiral sequence, and 0.89 for the radial sequence. CONCLUSION: The radial sequence enables similar accurate assessment of regional wall motion compared with the BH-SSFP sequence and yields image quality that is superior to that yielded by the spiral sequence and ECHO.

Myocardial viability: rapid assessment with delayed contrast-enhanced MR imaging with three-dimensional inversion-recovery prepared pulse sequence.

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.

Quantitative assessment of left ventricular function with interactive real-time spiral and radial MR imaging.

An interactive real-time spiral gradient-echo and an interactive real-time radial steady-state free precession sequence were investigated for the quantitative assessment of left ventricular function. Data were acquired in 18 patients without electrocardiographic triggering and breath holding. With the interactive real-time spiral gradient-echo sequence, significant underestimation of endocardial and epicardial volumes was demonstrated; with the interactive real-time radial steady-state free precession sequence, excellent agreement was shown with standard cardiac-triggered segmented k-space breath-hold steady-state free precession MR imaging. Interactive real-time radial steady-state free precession imaging allows accurate quantitative assessment of left ventricular volumes.

Strain rate measurement by doppler echocardiography allows improved assessment of myocardial viability inpatients with depressed left ventricular function.

OBJECTIVES: This study sought to evaluate whether objective assessment of the myocardial functional reserve, using strain rate imaging (SRI), allows accurate detection of viable myocardium. BACKGROUND: Strain rate imaging is a new echocardiographic modality that allows quantitative assessment of segmental myocardial contractility. METHODS: In 37 patients (age 58 +/- 9 years) with ischemic left ventricular dysfunction, myocardial viability was assessed using low-dose (10 microg/kg body weight per min) two-dimensional dobutamine stress echocardiography (DSE), tissue Doppler imaging, SRI and (18)F-fluorodeoxyglucose ((18)FDG) positron emission tomography (PET). The peak systolic tissue Doppler velocity and peak systolic myocardial strain rate were determined at baseline and during low-dose dobutamine stress from the apical views. RESULTS: A total of 192 segments with dyssynergy at rest were classified by (18)FDG PET as viable in 94 and nonviable in 98. An increase of peak systolic strain rate from rest to dobutamine stimulation by more than -0.23 1/s allowed accurate discrimination of viable from nonviable myocardium, as determined by (18)FDG PET with a sensitivity of 83% and a specificity of 84%. Receiver operating characteristic (ROC) curve analysis showed an area under the curve for prediction of nonviable myocardium, as determined by (18)FDG PET using SRI, of 0.89 (95% confidence interval [CI] 0.88 to 0.90), whereas the area under the ROC curve using tissue Doppler imaging was 0.63 (95% CI 0.61 to 0.65). CONCLUSIONS: The increase in the peak systolic strain rate during low-dose dobutamine stimulation allows accurate discrimination between different myocardial viability states. Strain rate imaging is superior to two-dimensional DSE and tissue Doppler imaging for the assessment of myocardial viability.