Stijntje D Roes

University Hospital of Lausanne, Lausanne, Vaud, Switzerland

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Publications (33)177.06 Total impact

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    ABSTRACT: OBJECTIVES: The objective of this study was to evaluate associations between aortic pulse wave velocity (PWV) and aortic and carotid vessel wall thickness (VWT) using cardiovascular magnetic resonance imaging (MRI) in patients with hypertension as compared with healthy adult volunteers. MATERIALS AND METHODS: Local medical ethics approval was obtained and the participants gave informed consent. Fifteen patients with hypertension (5 men and 10 women; mean [SD] age, 49 [14] years) and 15 age- and sex-matched healthy volunteers were prospectively included and compared. All participants underwent MRI examination for measuring aortic and carotid VWT and aortic PWV with well-validated MRI techniques at 1.5- and 3-T MRI systems: PWV was assessed from velocity-encoded MRI and VWT was assessed by using dual-inversion black-blood gradient-echo imaging techniques. Paired t tests were used for testing differences between the volunteers and the patients and Pearson correlation (r) and univariable and multivariable stepwise linear regression analyses were used to test associations between aortic and carotid arterial wall thickness and stiffness. RESULTS: Mean values for aortic PWV and aortic and carotid VWT (indexed for body surface area [BSA]) were all significantly higher in patients with hypertension as compared with the healthy volunteers (ie, aortic PWV, 7.0 ± 1.4 m/s vs 5.7 ± 1.3 m/s; aortic VWT/BSA, 0.12 ± 0.03 mL/m vs 0.10 ± 0.03 mL/m; carotid VWT/BSA, 0.04 ± 0.01 mL/m vs 0.03 ± 0.01 mL/m; all P < 0.01). Aortic PWV was highly correlated with aortic VWT/BSA (r = 0.76 and P = 0.002 in the patients vs r = 0.63 and P = 0.02 in the volunteers), and in the patients, aortic PWV was moderately correlated with carotid VWT/BSA (r = 0.50; P = 0.04). In the volunteers, correlation between aortic PWV and carotid VWT/BSA was not significant (r = 0.40; P = 0.13). In addition, aortic VWT/BSA was significantly correlated with carotid VWT/BSA, in both the patients (r = 0.60; P = 0.005) and volunteers (r = 0.57; P = 0.007). CONCLUSIONS: In the patients with hypertension and the healthy volunteers, the aortic PWV is associated more strongly with aortic wall thickness than with carotid wall thickness, reflecting site-specific coupling between vascular wall thickness and function.
    Investigative radiology 12/2012; · 4.85 Impact Factor
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    ABSTRACT: To evaluate the effect of lifestyle intervention in conjunction with rosiglitazone or placebo therapy on left ventricular (LV) mass, using cardiovascular magnetic resonance (CMR) in the metabolic syndrome. The present study was a pre-specified substudy of a double-blind randomized controlled trial evaluating the effect of lifestyle intervention in conjunction with rosiglitazone or placebo therapy on carotid artery atherosclerosis in the metabolic syndrome. From this original study population, 10 subjects from the placebo group and 10 from the rosiglitazone group were randomly selected. At baseline and follow-up (52 weeks), clinical and laboratory measurements were assessed and a CMR-examination was performed to evaluate LV mass indexed for body surface area (LV mass-I). Subsequently, the effect of therapy (rosiglitazone vs. placebo) and clinical and laboratory variables on LV mass-I was evaluated. In both groups, body mass index, waist circumference, systolic and diastolic blood pressure significantly decreased during follow-up. Interestingly, LV mass-I significantly decreased in the placebo group (48.9 ± 5.3 g/m2 vs. 44.3 ± 5.6 g/m2, p < 0.001) indicating reverse remodeling, whereas LV mass-I remained unchanged in the rosiglitazone group (54.7 ± 9.9 g/m2 vs. 53.7 ± 9.2 g/m2, p = 0.3). After correction for systolic and diastolic blood pressure and triglyceride, the kind of therapy (rosiglitazone vs. placebo) remained the only significant predictor of LV mass-I reduction. Lifestyle intervention resulted in a reduction of LV mass-I in the metabolic syndrome, indicating reverse remodeling. However, rosiglitazone therapy may have inhibited this positive reverse remodeling. Current Controlled Trials ISRCTN54951661.
    Journal of Cardiovascular Magnetic Resonance 01/2011; 13:65. · 4.44 Impact Factor
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    ABSTRACT: Surgical ventricular reconstruction has been proposed as a treatment option in heart failure patients with left ventricular (LV) aneurysm. The feasibility of this procedure has some limitations, and extensive preoperative evaluation is necessary to give the correct indication. For this purpose, magnetic resonance imaging (MRI) is currently considered the gold standard, providing accurate quantification of LV shape, size, and global and regional function together with the assessment of myocardial scar and mitral regurgitation severity. The aim of this study was to evaluate the accuracy of real-time three-dimensional echocardiography (RT3DE) as a potential alternative to MRI for this evaluation. A total of 52 patients with ischemic cardiomyopathy and LV aneurysm underwent a comprehensive analysis with two-dimensional echocardiography, RT3DE, and MRI. Excellent correlation (r=0.97, p<0.001) and agreement were found between RT3DE and MRI for quantification of LV volumes, ejection fraction, and sphericity index; in a segment-to-segment comparison, RT3DE was shown to be accurate also for the analysis of wall motion abnormalities (k=0.62) and LV regional thickness (k=0.56) as a marker of myocardial scar. In contrast, two-dimensional echocardiography significantly underestimated these variables. Furthermore, mitral regurgitant volume assessed by RT3DE showed excellent correlation (r=0.93) with regurgitant volume measured by MRI, without significant bias (=-0.7 mL/beat). In the management of heart failure patients with LV aneurysm, RT3DE provides an accurate and comprehensive assessment, including quantification of LV size, shape, global systolic function, regional wall motion, and myocardial scar together with precise evaluation of the severity of mitral regurgitation.
    The Annals of thoracic surgery 01/2011; 91(1):113-21. · 3.45 Impact Factor
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    Journal of Cardiovascular Magnetic Resonance 01/2011; · 4.44 Impact Factor
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    ABSTRACT: The present substudy of a recently published randomized trial aimed to investigate the effect of intramyocardial bone marrow cell injection on diastolic function in patients with chronic myocardial ischemia. In a total of 50 patients, diastolic function was evaluated before and 3 months after bone marrow cell injection using standard echocardiography and strain analysis. In addition, MRI-derived transmitral flow measurements were obtained in a subset of 36 patients. Left ventricular ejection fraction increased from 50±5% to 54±7% in the bone marrow cell group, which was a significant improvement as compared with the placebo group (52±5% versus 51±7%, P=0.001). Filling pressure estimate E/E' ratio improved from 14±5 at baseline to 12±4 at 3 months in the bone marrow cell group, whereas no improvement was observed in the placebo group (13±4 versus 13±5). The improvement in E/E' ratio was significantly larger in the bone marrow cell group (P=0.008). Furthermore, the E/A peak flow ratio as assessed by MRI showed a significant increase in the bone marrow cell group as compared with the placebo group (+0.16±0.25 versus -0.04±0.21, P=0.01), which was mainly related to an increase in the early (E) peak flow rate in the bone marrow cell group (from 407±96 mL/s to 468±110 mL/s, P=0.009 as compared with the placebo group). The current study demonstrates that intramyocardial bone marrow cell injection is associated with a beneficial effect on myocardial relaxation and filling pressures in patients with chronic myocardial ischemia.
    Circulation Cardiovascular Imaging 01/2011; 4(2):122-9. · 5.80 Impact Factor
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    ABSTRACT: To evaluate accuracy and reproducibility of flow velocity and volume measurements in a phantom and in human coronary arteries using breathhold velocity-encoded (VE) MRI with spiral k-space sampling at 3 Tesla. Flow velocity assessment was performed using VE MRI with spiral k-space sampling. Accuracy of VE MRI was tested in vitro at five constant flow rates. Reproducibility was investigated in 19 healthy subjects (mean age 25.4 +/- 1.2 years, 11 men) by repeated acquisition in the right coronary artery (RCA). MRI-measured flow rates correlated strongly with volumetric collection (Pearson correlation r = 0.99; P < 0.01). Due to limited sample resolution, VE MRI overestimated the flow rate by 47% on average when nonconstricted region-of-interest segmentation was used. Using constricted region-of-interest segmentation with lumen size equal to ground-truth luminal size, less than 13% error in flow rate was found. In vivo RCA flow velocity assessment was successful in 82% of the applied studies. High interscan, intra- and inter-observer agreement was found for almost all indices describing coronary flow velocity. Reproducibility for repeated acquisitions varied by less than 16% for peak velocity values and by less than 24% for flow volumes. 3T breathhold VE MRI with spiral k-space sampling enables accurate and reproducible assessment of RCA flow velocity.
    Journal of Magnetic Resonance Imaging 05/2010; 31(5):1215-23. · 2.57 Impact Factor
  • Journal of The American College of Cardiology - J AMER COLL CARDIOL. 01/2010; 55(10).
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    ABSTRACT: PURPOSE To evaluate the accuracy and reproducibility of a breath-hold velocity encoded (VE) cine sequence with spiral k-space sampling at 3T for assessment of coronary flow. METHOD AND MATERIALS Accuracy was tested in a phantom set-up. Ten constant flow rates (pump settings 0.9ml/s to 7.3ml/s) measured with MR,were compared with volumetric flow measurements recorded distal to the phantom. Reproducibility was investigated in healthy volunteers. Nineteen healthy volunteers (11 men, mean age 25.4±1.2 years) underwent breath-hold (16-24s) VE coronary flow imaging with spiral k-space sampling of the right coronary artery (RCA). The acquisition was repeated twice. In the resulting flow velocity maps the following parameters were assessed: peak systolic and diastolic velocity (PSV and PDV)(cm/s), meanVmax per cardiac cycle (cm/s), coronary flow (ml/cycle), ratio of PSV and PDV to mean Vmax (pulsatility of Vmax-pattern) and the ratio between peak systolic and diastolic velocity (PSV/PDV). Repeated acquisitions were compared using the paired t-test and the reproducibility of coronary flow assessment was evaluated using intraclass correlation coefficients (ICCs). RESULTS Phantom experiments showed less than 7% error for the applied flow rates. MRI-measured flow was strongly correlated with volumetric flow (ICC=0.99). Flow assessment in the RCA was successfully repeated in 15 volunteers. Mean difference between the repeated acquisitions was not significant for any of the parameters describing the velocity pattern. Good agreement was found between the repeated acquisitions: ICCs were significant for all parameters describing the velocity pattern, except PDV/meanVmax. ICC’s concerning intraobserver, interobserver and interscan reproducibility were excellent for PSV (0.99, 0.98, and 0.88, respectively). CONCLUSION 1) Accuracy of spiral k-space sampling 3Tesla MR flow mapping was validated in vitro. 2) Fast, reproducible and accurate MR assessment of flow velocity patterns in the RCA is feasible at 3 Tesla. 3) PSV is a promising parameter for description of the coronary flow pattern. CLINICAL RELEVANCE/APPLICATION Breath-hold VE cine MRI with spiral k-space sampling at 3T may be useful for assessment of abnormal coronary flow in patients with coronary artery disease.
    Radiological Society of North America 2009 Scientific Assembly and Annual Meeting; 11/2009
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    ABSTRACT: The aim of this study was to evaluate feasibility and accuracy of real-time 3-dimensional (3D) echocardiography for quantification of mitral regurgitation (MR), in a head-to-head comparison with velocity-encoded cardiac magnetic resonance (VE-CMR). Accurate grading of MR severity is crucial for appropriate patient management but remains challenging. VE-CMR with 3D three-directional acquisition has been recently proposed as the reference method. A total of 64 patients with functional MR were included. A VE-CMR acquisition was applied to quantify mitral regurgitant volume (Rvol). Color Doppler 3D echocardiography was applied for direct measurement, in "en face" view, of mitral effective regurgitant orifice area (EROA); Rvol was subsequently calculated as EROA multiplied by the velocity-time integral of the regurgitant jet on the continuous-wave Doppler. To assess the relative potential error of the conventional approach, color Doppler 2-dimensional (2D) echocardiography was performed: vena contracta width was measured in the 4-chamber view and EROA calculated as circular (EROA-4CH); EROA was also calculated as elliptical (EROA-elliptical), measuring vena contracta also in the 2-chamber view. From these 2D measurements of EROA, the Rvols were also calculated. The EROA measured by 3D echocardiography was significantly higher than EROA-4CH (p < 0.001) and EROA-elliptical (p < 0.001), with a significant bias between these measurements (0.10 cm(2) and 0.06 cm(2), respectively). Rvol measured by 3D echocardiography showed excellent correlation with Rvol measured by CMR (r = 0.94), without a significant difference between these techniques (mean difference = -0.08 ml/beat). Conversely, 2D echocardiographic approach from the 4-chamber view significantly underestimated Rvol (p = 0.006) as compared with CMR (mean difference = 2.9 ml/beat). The 2D elliptical approach demonstrated a better agreement with CMR (mean difference = -1.6 ml/beat, p = 0.04). Quantification of EROA and Rvol of functional MR with 3D echocardiography is feasible and accurate as compared with VE-CMR; the currently recommended 2D echocardiographic approach significantly underestimates both EROA and Rvol.
    JACC. Cardiovascular imaging 11/2009; 2(11):1245-52. · 14.29 Impact Factor
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    ABSTRACT: Our aim was to assess the predictive value of myocardial infarct size assessed with late gadolinium-enhanced (LGE) magnetic resonance imaging (MRI) in medically treated patients with chronic myocardial infarction relative to contractile reserve on low-dose dobutamine magnetic resonance (DSMR) for long-term event-free survival. Information on the relative merits of scar tissue and contractile reserve to predict long-term prognosis in patients with chronic myocardial infarction is lacking. A total of 177 patients with known coronary artery disease and scar tissue on LGE MRI were enrolled. Left ventricular (LV) functional parameters at rest and during low-dose DSMR were assessed, and the wall motion score index was calculated. Eleven patients (6.2%) suffered an event during follow-up (average 20.3 months). Infarct size was a stronger predictor of events than LV ejection fraction and LV volumes at rest and during low-dose DSMR. Myocardial infarct size was used to separate patients at high risk (spatial extent > or =6 segments, n = 98) from those at low risk (spatial extent <6 segments, n = 79) for mortality. In the subgroup of patients at high risk, transmurality of infarct was not a predictor of events. However, the presence of contractile reserve (n = 63) was associated with a significantly higher number of events (12.7%) compared with no change in wall motion score index (6.7%; n = 15; p = 0.008). Myocardial infarct size on LGE MRI is a stronger predictor of clinical outcome than contractile reserve in medically treated patients with myocardial infarction. In patients with large myocardial scar, the presence of contractile reserve is more important for the prediction of events than scar tissue.
    Journal of the American College of Cardiology 11/2009; 54(19):1770-7. · 14.09 Impact Factor
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    ABSTRACT: The purpose of the present study was to compare longitudinal strain assessed by two-dimensional speckle tracking with scar tissue on contrast-enhanced magnetic resonance imaging (MRI) in patients with chronic ischemic left ventricular (LV) dysfunction. The aim was also to define a cutoff value for regional strain to discriminate between viable myocardium and transmural scar. Ninety patients with chronic ischemic LV dysfunction underwent transthoracic echocardiography to measure global and segmental (regional) longitudinal LV strain using two-dimensional speckle tracking and cine MRI followed by contrast-enhanced MRI to assess segmental LV function and the segmental/global (transmural) extent of scar tissue. The optimal cutoff value for regional strain to discriminate between segments with viable myocardium and segments with transmural scar was also determined. A good correlation was found between global LV strain and the global extent of scar tissue on contrast-enhanced MRI (R = 0.62, p <0.001). The mean segmental strain in segments without scar tissue was -10.4% +/- 5.2% compared with 0.6% +/- 4.9% in segments with transmural scar tissue (p <0.001). A strain value of -4.5% discriminated between segments with viable myocardium and segments with transmural scar tissue on contrast-enhanced MRI with a sensitivity of 81.2% and specificity of 81.6%. In conclusion, global and regional longitudinal strain measured with two-dimensional speckle tracking is associated with the global and regional (transmural) extent of scar tissue on contrast-enhanced MRI. A cutoff value of -4.5% for regional strain discriminated between segments with viable myocardium and those with transmural scar tissue on contrast-enhanced MRI with a sensitivity of 81.2% and specificity of 81.6%.
    The American journal of cardiology 09/2009; 104(3):312-7. · 3.58 Impact Factor
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    ABSTRACT: To validate 3-dimensional (3D) 3-directional velocity-encoded (VE) magnetic resonance imaging (MRI) for flow assessment through all 4 heart valves simultaneously with retrospective valve-tracking during off-line analysis in healthy volunteers and in patients with valvular regurgitation. Three-dimensional 3-directional VE MRI was performed in 22 healthy volunteers and in 29 patients with ischemic cardiomyopathy who were suspected of valvular regurgitation and net flow volumes through the 4 heart valves were compared. Furthermore, the analysis was repeated for each valve in 10 healthy volunteers and in 10 regurgitant valves to assess intra- and interobserver agreement for assessment of respectively net flow volumes and regurgitation fraction. In healthy volunteers, the average net flow volume through the mitral valve, tricuspid valve, aortic valve, and pulmonary valve was 85 +/- 20 mL, 85 +/- 21 mL, 83 +/- 19 mL, 82 +/- 21 mL, respectively. Strong correlations between net flow volumes through the 4 heart valves were observed (intraclass correlation coefficients [ICC] 0.93-0.95) and the coefficient of variance (CV) was small (6%-9%). The repeated analysis by the same observer and by a second observer yielded good agreement for measurement of net flow volumes (ICC: 0.93-0.99 and CV: 3%-7%). Strong correlations between the net flow volumes through the 4 heart valves were also observed in the patients with valvular regurgitation (ICC: 0.85-0.95 and CV: 7%-18%). The average net flow volume through the mitral valve, tricuspid valve, aortic valve, and pulmonary valve was 63 +/- 20 mL, 63 +/- 20 mL, 63 +/- 20 mL, 63 +/- 20 mL, respectively. Furthermore, the intra- and interobserver agreement for assessment of regurgitation fraction was good (ICC: 0.86 and 0.85, CV: 12% and 13%). Flow assessment using 3D 3-directional VE MR with retrospective valve-tracking during off-line analysis enables accurate quantification of net flow volumes through 4 heart valves within a single acquisition in healthy volunteers and in patients with valvular regurgitation.
    Investigative radiology 09/2009; 44(10):669-75. · 4.85 Impact Factor
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    ABSTRACT: To assess the relative value of a novel measure of left ventricular (LV) dyssynchrony derived from magnetic resonance imaging (MRI) and the extent of scar tissue for prediction of response to cardiac resynchronization therapy (CRT). Thirty-five heart failure patients scheduled for CRT were included. Left ventricular dyssynchrony was defined as the standard deviation of 16 segment time-to-maximum radial wall thickness (SDt-16) obtained from a cine-set of short-axis slices. Delayed-enhanced MRI was performed for scar analysis. Echocardiography was used to determine response to CRT (reduction > or =15% in LV end-systolic volume 6 months after implantation). At follow-up, 21 patients (60%) were classified as responders. On MRI, SDt-16 was significantly higher in responders compared with non-responders (median 97 vs. 60 ms, P < 0.001), whereas the total extent of scar was larger in non-responders (median 35% vs. 3% in responders, P < 0.001). At the logistic regression analysis, SDt-16 was directly associated (OR = 6.3, 95% CI 3.1-9.9, P < 0.001) and the total extent of scar was inversely associated (OR = 0.52, 95% CI 0.43-0.87, P < 0.001) with response to CRT. Magnetic resonance imaging offers the unique opportunity to assess LV dyssynchrony and scar extent in a single session. Both these parameters are important predictors of echocardiographic response to CRT.
    European Heart Journal 08/2009; 30(19):2360-7. · 14.72 Impact Factor
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    ABSTRACT: Previous studies have suggested that bone marrow cell injection may improve myocardial perfusion and left ventricular (LV) function in patients with chronic myocardial ischemia. To investigate the effect of intramyocardial bone marrow cell injection on myocardial perfusion and LV function in patients with chronic myocardial ischemia. Randomized, double-blind, placebo-controlled trial at a Netherlands university hospital, May 1, 2005-March 3, 2008 (6-month follow-up ended September 2008) of 50 patients with chronic myocardial ischemia (mean age [SD], 64 [8] years; 43 men). Inclusion criteria: severe angina pectoris despite optimal medical therapy and myocardial ischemia. All patients were ineligible for conventional revascularization. Intramyocardial injection of 100 x 10(6) autologous bone marrow-derived mononuclear cells or placebo solution. Primarily, the summed stress score, a 17-segment score for stress myocardial perfusion assessed by Tc-99m tetrofosmin single-photon emission computed tomography (SPECT). Secondary included LV ejection fraction (LVEF), Canadian Cardiovascular Society (CCS) class, and Seattle Angina Questionnaire quality-of-life score (mean difference >5% considered clinically significant). After 3-month follow-up, the summed stress score (mean [SD]) improved from 23.5 (4.7) to 20.1 (4.6) (P < .001) in the bone marrow cell group, compared with a decrease from 24.8 (5.5) to 23.7 (5.4) (P = .004) in the placebo group. In the bone marrow cell-treated patients who underwent magnetic resonance imaging (MRI), a 3% absolute increase in LVEF was observed at 3 months (95% CI, 0.5% to 4.7%; n = 18), but the placebo group showed no improvement. CCS angina score improved significantly in the bone marrow cell group (6-month absolute difference, -0.79; 95% CI, -1.10 to -0.48; P < .001) compared with no significant improvement in the placebo group. Quality-of-life score increased from 56% (9%) to 64% (12%) at 3 months and 69% (12%) at 6 months in bone marrow cell-treated patients, compared with a smaller increase in the placebo group from 57% (11%) to 61% (14%) to 64% (17%). The improvements in CCS class and quality of life score were significantly greater in bone marrow cell-treated patients than in placebo-treated patients (P = .03 and P = .04, respectively). In this short-term study of patients with chronic myocardial ischemia refractory to medical treatment, intramyocardial bone marrow cell injection resulted in a statistically significant but modest improvement in myocardial perfusion compared with placebo. Further studies are required to assess long-term results and efficacy for mortality and morbidity. trialregister.nl Identifier: NTR400 and isrctn.org Identifier: ISRCTN58194927.
    JAMA The Journal of the American Medical Association 06/2009; 301(19):1997-2004. · 29.98 Impact Factor
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    ABSTRACT: The relation between infarct tissue heterogeneity on contrast-enhanced MRI and the occurrence of spontaneous ventricular arrhythmia (or sudden cardiac death) is unknown. Therefore, the study purpose was to evaluate the predictive value of infarct tissue heterogeneity assessed with contrast-enhanced MRI on the occurrence of spontaneous ventricular arrhythmia with subsequent implantable cardioverter-defibrillator (ICD) therapy (as surrogate of sudden cardiac death) in patients with previous myocardial infarction. Ninety-one patients (age, 65+/-11 years) with previous myocardial infarction scheduled for ICD implantation underwent cine MRI to evaluate left ventricular function and volumes and contrast-enhanced MRI for characterization of scar tissue (infarct gray zone as measure of infarct tissue heterogeneity, infarct core, and total infarct size). Appropriate ICD therapy was documented in 18 patients (20%) during a median follow-up of 8.5 months (interquartile range, 2.1 to 20.3). Multivariable Cox proportional hazards analysis revealed that infarct gray zone was the strongest predictor of the occurrence of spontaneous ventricular arrhythmia with subsequent ICD therapy (hazard ratio, 1.49/10 g; CI, 1.01 to 2.20; chi(2)=4.0; P=0.04). Infarct tissue heterogeneity on contrast-enhanced MRI is the strongest predictor of spontaneous ventricular arrhythmia with subsequent ICD therapy (as surrogate of sudden cardiac death) among other clinical and MRI variables, that is, total infarct size and left ventricular function and volumes, in patients with previous myocardial infarction.
    Circulation Cardiovascular Imaging 05/2009; 2(3):183-90. · 5.80 Impact Factor
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    ABSTRACT: The purpose of this study was to compare contrast-enhanced MRI and nuclear imaging with (99m)Tc-tetrofosmin and (18)F-fluorodeoxyglucose ((18)F-FDG) single photon emission computed tomography (SPECT) for assessment of myocardial viability. Included in the study were 60 patients with severe ischaemic left ventricular (LV) dysfunction who underwent contrast-enhanced MRI, (99m)Tc-tetrofosmin and (18)F-FDG SPECT. Myocardial segments were assigned a wall motion score from 0 (normokinesia) to 4 (dyskinesia) and a scar score from 0 (no scar) to 4 (76-100% transmural extent). Furthermore, (99m)Tc-tetrofosmin and (18)F-FDG segmental tracer uptake was categorized from 0 (tracer activity >75%) to 3 (tracer activity <25%). Dysfunctional segments were classified into viability patterns on SPECT: normal perfusion/(18)F-FDG uptake, perfusion/(18)F-FDG mismatch, and mild or severe perfusion/(18)F-FDG match. Minimal scar tissue was observed on contrast-enhanced MRI (scar score 0.4+/-0.8) in segments with normal perfusion/(18)F-FDG uptake, whereas extensive scar tissue (scar score 3.1+/-1.0) was noted in segments with severe perfusion/(18)F-FDG match (p < 0.001). High agreement (91%) for viability assessment between contrast-enhanced MRI and nuclear imaging was observed in segments without scar tissue on contrast-enhanced MRI as well as in segments with transmural scar tissue (83%). Of interest, disagreement was observed in segments with subendocardial scar tissue on contrast-enhanced MRI. Agreement between contrast-enhanced MRI and nuclear imaging for assessment of viability was high in segments without scar tissue and in segments with transmural scar tissue on contrast-enhanced MRI. However, evident disagreement was observed in segments with subendocardial scar tissue on contrast-enhanced MRI, illustrating that the nonenhanced epicardial rim can contain either normal or ischaemically jeopardized myocardium.
    European Journal of Nuclear Medicine 01/2009; 36(4):594-601. · 4.53 Impact Factor
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    ABSTRACT: The purpose of this study was to evaluate a free-breathing three-dimensional (3D) dual inversion-recovery (DIR) segmented k-space gradient-echo (turbo field echo [TFE]) imaging sequence at 3T for the quantification of aortic vessel wall dimensions. The effect of respiratory motion suppression on image quality was tested. Furthermore, the reproducibility of the aortic vessel wall measurements was investigated. Seven healthy subjects underwent 3D DIR TFE imaging of the aortic vessel wall with and without respiratory navigator. Subsequently, this sequence with respiratory navigator was performed twice in 10 healthy subjects to test its reproducibility. The signal-to-noise (SNR), contrast-to-noise ratio (CNR), vessel wall sharpness, and vessel wall volume (VWV) were assessed. Data were compared using the paired t-test, and the reproducibility of VWV measurements was evaluated using intraclass correlation coefficients (ICCs). SNR, CNR, and vessel wall sharpness were superior in scans performed with respiratory navigator compared to scans performed without. The ICCs concerning intraobserver, interobserver, and interscan reproducibility were excellent (0.99, 0.94, and 0.95, respectively). In conclusion, respiratory motion suppression substantially improves image quality of 3D DIR TFE imaging of the aortic vessel wall at 3T. Furthermore, this optimized technique with respiratory motion suppression enables assessment of aortic vessel wall dimensions with high reproducibility.
    Magnetic Resonance in Medicine 01/2009; 61(1):35-44. · 3.27 Impact Factor
  • Journal of Cardiovascular Magnetic Resonance 01/2009; · 4.44 Impact Factor
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    ABSTRACT: PURPOSE Determine the agreement between contrast-enhanced MRI (ce-MRI) and nuclear imaging for assessment of viability in patients with severe ischemic LV dysfunction. METHOD AND MATERIALS Patients (n = 25) with severe ischemic LV dysfunction (EF 25 ± 11%) were studied using cine MRI, ce-MRI, 99m Tc-tetrofosmin single photon emission computed tomography (SPECT) and 18F-FDG SPECT. Each segment was assigned a wall motion score using a 17-segment model (0: normokinesia to 4: dyskinesia) and a scar score (0: no infarction to 4: 76-100% transmurality). Furthermore, 99m Tc-tetrofosmin and 18F-FDG segmental tracer uptake was categorized (0: tracer activity > 75% to 3: tracer activity < 25%). Dysfunctional segments were classified into viability patterns assessed with SPECT: normal pattern (normal perfusion and glucose metabolism), mismatch pattern (decreased perfusion, increased glucose metabolism), mild match pattern (mild decrease in perfusion and glucose metabolism), and severe match pattern (severe decrease in perfusion and glucose metabolism). Differences in scar score between viability patterns was assessed using one-way ANOVA analysis. RESULTS Of all analyzed segment (n = 425), 285 (67%) showed abnormal wall motion. Mean scar score was 0.3±0.7 in segments with a normal viability pattern, 1.1±1.3 in segments with mismatch, 1.4±1.0 in mild match and 2.7±1.1 in severe match (p<0.001 between all patterns, non-significant between mismatch and mild match). CONCLUSION Agreement between MRI and nuclear imaging for assessment of viability is high in segments with transmural scar on ce-MRI. However, non-enhanced tissue on ce-MRI can represent normal or jeopardized (perfusion-metabolism mismatch) myocardium CLINICAL RELEVANCE/APPLICATION The high agreement between MRI and nuclear imaging for assessment of viability in segments with transmural scar on ce-MRI improves understanding and applicability of CE-MRI.
    Radiological Society of North America 2008 Scientific Assembly and Annual Meeting; 12/2008
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    ABSTRACT: To validate flow assessment performed with three-dimensional (3D) three-directional velocity-encoded (VE) magnetic resonance (MR) imaging with retrospective valve tracking and to compare this modality with conventional two-dimensional (2D) one-directional VE MR imaging in healthy subjects and patients with regurgitation. Patients and volunteers gave informed consent, and local medical ethics committee approval was obtained. Patient data were selected retrospectively and randomly from a database of MR studies obtained between July 2006 and July 2007. The 3D three-directional VE MR images were first validated in vitro and compared with 2D one-directional VE MR images. Mitral valve (MV) and tricuspid valve (TV) flow were assessed in 10 volunteers without valve insufficiency and 20 patients with valve insufficiency, with aortic systolic stroke volume (ASSV) as the reference standard. Phantom validation showed less than 5% error for both techniques. In volunteers, 3D three-directional VE MR images showed no bias for MV or TV flow when compared with ASSV, whereas 2D one-directional VE MR images showed significant bias for MV flow (15% overestimation, P < .01). TV flow showed 25% overestimation; however, this was insignificant because of the high standard deviation. Correlation with ASSV was strong for 3D three-directional VE MR imaging (r = 0.96, P < .01 for MV flow; r = 0.88, P < .01 for TV flow) and between MV and TV flow (r = 0.91, P < .01); however, correlation was weaker for 2D one-directional VE MR imaging (r = 0.80, P < .01 for MV flow; r = 0.22, P = .55 for TV flow) and between MV flow and TV flow (r = 0.34, P = .34). In patients (mean regurgitation fractions of 13% and 10% for MV flow and TV flow, respectively), correlation between MV flow and TV flow for 3D three-directional VE MR imaging was strong (r = 0.97, P < .01). Use of 3D three-directional VE MR imaging enables accurate MV and TV flow quantification, even in patients with valve regurgitation.
    Radiology 10/2008; 249(3):792-800. · 6.34 Impact Factor