OBJECTIVES This study aimed to demonstrate the feasibility of multidetector row computed tomography (CT) for assessment of diastolic function in comparison with 2-dimensional (2D) echocardiography... Show moreOBJECTIVES This study aimed to demonstrate the feasibility of multidetector row computed tomography (CT) for assessment of diastolic function in comparison with 2-dimensional (2D) echocardiography using tissue Doppler imaging (TDI). BACKGROUND Diastolic left ventricular (LV) function plays an important role in patients with cardiovascular disease. 2D echocardiography using TDI has been used most commonly to evaluate diastolic LV function. Although the role of cardiac CT imaging for evaluation of coronary atherosclerosis has been explored extensively, its feasibility to evaluate diastolic function has not been studied. METHODS Patients who had undergone 64-multidetector row CT and 2D echocardiography with TDI were enrolled. Diastolic function was evaluated using early (E) and late (A) transmitral peak velocity (cm/s) and peak mitral septal tissue velocity (Ea; cm/s). Peak transmitral velocity (cm/s) was calculated by dividing peak diastolic transmitral flow (ml/s) by the corresponding mitral valve area (cm(2)). Mitral septal tissue velocity was calculated from changes in LV length per cardiac phase. Subsequently, the estimation of LV filling pressures (E/Ea) was determined. RESULTS Seventy patients (46 men; mean age 55 +/- 11 years) who had undergone cardiac CT and 2D echocardiography with TDI were included. Good correlations were observed between cardiac CT and 2D echocardiography for assessment of E (r = 0.73; p < 0.01), E/A (r = 0.87; p < 0.01), Ea (r = 0.82; p < 0.01), and E/Ea (r = 0.81; p < 0.01). Moreover, a good diagnostic accuracy (79%) was found for detection of diastolic dysfunction using cardiac CT. Finally, the study showed a low intraobserver and interobserver variability for assessment of diastolic function on cardiac CT. CONCLUSIONS Cardiac CT imaging showed good correlations for transmitral velocity, mitral septal tissue velocity, and estimation of LV filling pressures when compared with 2D echocardiography. Additionally, cardiac CT and 2D echocardiography were comparable for assessment of diastolic dysfunction. Accordingly, cardiac CT may provide information on diastolic dysfunction. (J Am Coll Cardiol Img 2011;4:246-56) (C) 2011 by the American College of Cardiology Foundation Show less
The introductory chapter provides an overview of various aspects related to quantitative analysis of cardiovascular MR (CMR) imaging studies. Subsequently, the thesis describes several automated... Show moreThe introductory chapter provides an overview of various aspects related to quantitative analysis of cardiovascular MR (CMR) imaging studies. Subsequently, the thesis describes several automated methods for quantitative assessment of left ventricular function from CMR imaging studies. Several novel computer algorithms are introduced and validated for automated segmentation of short-axis CMR images and validated by comparing functional results derived from automated segmentation with results derived from manually traced contours. In addition an automated method is presented for assessment of flow through the aorta based on Phase-Contrast flow velocity mapping MRI. Finally a method is presented for accurate assessment of the thickness of the left ventricular myocardium taking advantage of the three-dimensional nature of MRI. Show less
Brandts, A.; Bertini, M.; Dijk, E.J. van; Delgado, V.; Marsan, N.A.; Geest, R.J. van der; ... ; Westenberg, J.J.M. 2011
Purpose: To compare parameters describing left ventricular (LV) diastolic function obtained with three-dimensional (3D) three-directional velocity-encoded (VE) MRI with retrospective valve tracking... Show morePurpose: To compare parameters describing left ventricular (LV) diastolic function obtained with three-dimensional (3D) three-directional velocity-encoded (VE) MRI with retrospective valve tracking and two-dimensional (2D) one-directional VE MRI in patients with ischemic heart failure. Second, to compare classification of LV diastolic function, and in particular for discriminating restrictive filling patterns, with both MRI techniques versus Doppler echocardiography. Materials and Methods: The 3D and 2D VE ME! early (E) and atrial (A) peak flow rate indices, determined from transmitral waveform analyses, were compared. Also, net forward flow volume per cycle and transmitral regurgitation fraction were determined. Agreement in classifying diastolic filling patterns between 3D and 2D VE MRI versus Doppler echocardiography was evaluated using kappa statistics. Results: The 3D three-directional VE MRI with retrospective valve tracking was statistically significantly different from 2D one-directional VE MRI for net forward flow volume and regurgitation fraction through the mitral valve and all parameters describing the diastolic waveform filling pattern, except for the E deceleration time and E/A filling ratio. Kappa-agreement between 3D three-directional VE MRI with retrospective valve tracking and echocardiography for classifying diastolic filling patterns was superior to 2D one-directional VE MRI and echocardiography (i.e., kappa = 0.91 versus kappa = 0.79, respectively). Conclusion: The 3D three-directional VE MRI with retrospective valve tracking better describes LV diastolic function as compared to 2D one-directional VE MRI in patients with ischemic heart failure. Show less
Background. 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... Show moreBackground. 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. Methods. A total of 52 patients with ischemic cardiomyopathy and LV aneurysm underwent a comprehensive analysis with two-dimensional echocardiography, RT3DE, and MRI. Results. 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). Conclusions. 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. (Ann Thorac Surg 2011;91:113-22) (C) 2011 by The Society of Thoracic Surgeons Show less
Wijnmaalen, A.P.; Geest, R.J. van der; Taxis, C.F.B.V. van; Siebelink, H.M.J.; Kroft, L.J.M.; Bax, J.J.; ... ; Zeppenfeld, K. 2011
Aims Substrate-based ablation of ventricular tachycardia (VT) relies on electroanatomical voltage mapping (EAVM). Integration of scar information from contrast-enhanced magnetic resonance imaging ... Show moreAims Substrate-based ablation of ventricular tachycardia (VT) relies on electroanatomical voltage mapping (EAVM). Integration of scar information from contrast-enhanced magnetic resonance imaging (CE-MRI) with EAVM may provide supplementary information. This study assessed the relation between electrogram voltages and CE-MRI scar characteristics using real-time integration and reversed registration. Methods and results Fifteen patients without implantable cardiac defibrillator (14 males, 64 +/- 9 years) referred for VT ablation after myocardial infarction underwent CE-MRI. Contours of the CE-MRI were used to create three-dimensional surface meshes of the left ventricle (LV), aortic root, and left main stem (LM). Real-time integration of CE-MRI-derived scar meshes with EAVM of the LV and aortic root was performed using the LM and the CARTO surface registration algorithm. Merging of CE-MRI meshes with EAVM was successful with a registration error of 3.8 +/- 0.6 mm. After the procedure, voltage amplitudes of each mapping point were superimposed on the corresponding CE-MRI location using the reversed registration matrix. Infarcts on CE-MRI were categorized by transmurality and signal intensity. Local bipolar and unipolar voltages decreased with increasing scar transmurality and were influenced by scar heterogeneity. Ventricular tachycardia reentry circuit isthmus sites were correlated to CE-MRI scar location. In three patients, VT isthmus sites were located in scar areas not identified by EAVM. Conclusion Integration of MRI-derived scar maps with EAVM during VT ablation is feasible and accurate. Contrast-enhanced magnetic resonance imaging identifies non-transmural scars and infarct grey zones not detected by EAVM according to the currently used voltage criteria and may provide important supplementary substrate information in selected patients. Show less
Wijnmaalen, A.P.; Geest, R.J. van der; Taxis, C.F.B.V. van; Siebelink, H.M.J.; Kroft, L.J.M.; Bax, J.J.; ... ; Zeppenfeld, K. 2011
AIMS Substrate-based ablation of ventricular tachycardia (VT) relies on electroanatomical voltage mapping (EAVM). Integration of scar information from contrast-enhanced magnetic resonance imaging ... Show moreAIMS Substrate-based ablation of ventricular tachycardia (VT) relies on electroanatomical voltage mapping (EAVM). Integration of scar information from contrast-enhanced magnetic resonance imaging (CE-MRI) with EAVM may provide supplementary information. This study assessed the relation between electrogram voltages and CE-MRI scar characteristics using real-time integration and reversed registration. METHODS AND RESULTS Fifteen patients without implantable cardiac defibrillator (14 males, 64 ± 9 years) referred for VT ablation after myocardial infarction underwent CE-MRI. Contours of the CE-MRI were used to create three-dimensional surface meshes of the left ventricle (LV), aortic root, and left main stem (LM). Real-time integration of CE-MRI-derived scar meshes with EAVM of the LV and aortic root was performed using the LM and the CARTO surface registration algorithm. Merging of CE-MRI meshes with EAVM was successful with a registration error of 3.8 ± 0.6 mm. After the procedure, voltage amplitudes of each mapping point were superimposed on the corresponding CE-MRI location using the reversed registration matrix. Infarcts on CE-MRI were categorized by transmurality and signal intensity. Local bipolar and unipolar voltages decreased with increasing scar transmurality and were influenced by scar heterogeneity. Ventricular tachycardia reentry circuit isthmus sites were correlated to CE-MRI scar location. In three patients, VT isthmus sites were located in scar areas not identified by EAVM. CONCLUSION Integration of MRI-derived scar maps with EAVM during VT ablation is feasible and accurate. Contrast-enhanced magnetic resonance imaging identifies non-transmural scars and infarct grey zones not detected by EAVM according to the currently used voltage criteria and may provide important supplementary substrate information in selected patients. Show less
Kirisli, H.A.; Schaap, M.; Klein, S.; Papadopoulou, S.L.; Bonardi, M.; Chen, C.H.; ... ; Niessen, W.J. 2010
Purpose: Computed tomography angiography (CTA) is increasingly used for the diagnosis of coronary artery disease (CAD). However, CTA is not commonly used for the assessment of ventricular and... Show morePurpose: Computed tomography angiography (CTA) is increasingly used for the diagnosis of coronary artery disease (CAD). However, CTA is not commonly used for the assessment of ventricular and atrial function, although functional information extracted from CTA data is expected to improve the diagnostic value of the examination. In clinical practice, the extraction of ventricular and atrial functional information, such as stroke volume and ejection fraction, requires accurate delineation of cardiac chambers. In this paper, we investigated the accuracy and robustness of cardiac chamber delineation using a multiatlas based segmentation method on multicenter and multivendor CTA data. Methods: A fully automatic multiatlas based method for segmenting the whole heart (i.e., the outer surface of the pericardium) and cardiac chambers from CTA data is presented and evaluated. In the segmentation approach, eight atlas images are registered to a new patient's CTA scan. The eight corresponding manually labeled images are then propagated and combined using a per voxel majority voting procedure, to obtain a cardiac segmentation. Results: The method was evaluated on a multicenter/multivendor database, consisting of (1) a set of 1380 Siemens scans from 795 patients and (2) a set of 60 multivendor scans (Siemens, Philips, and GE) from different patients, acquired in six different institutions worldwide. A leave-one-out 3D quantitative validation was carried out on the eight atlas images; we obtained a mean surface-to-surface error of 0.94 +/- 1.12 mm and an average Dice coefficient of 0.93 was achieved. A 2D quantitative evaluation was performed on the 60 multivendor data sets. Here, we observed a mean surface-to-surface error of 1.26 +/- 1.25 mm and an average Dice coefficient of 0.91 was achieved. In addition to this quantitative evaluation, a large-scale 2D and 3D qualitative evaluation was performed on 1380 and 140 images, respectively. Experts evaluated that 49% of the 1380 images were very accurately segmented (below 1 mm error) and that 29% were accurately segmented (error between 1 and 3 mm), which demonstrates the robustness of the presented method. Conclusions: A fully automatic method for whole heart and cardiac chamber segmentation was presented and evaluated using multicenter/multivendor CTA data. The accuracy and robustness of the method were demonstrated by successfully applying the method to 1420 multicenter/multivendor data sets. (C) 2010 American Association of Physicists in Medicine. [DOI: 10.1118/1.3512795] Show less
Objective: To investigate the natural course of carotid plaque progression in transient ischemic attack/stroke patients by using serial multisequence magnetic resonance imaging (MRI). Materials and... Show moreObjective: To investigate the natural course of carotid plaque progression in transient ischemic attack/stroke patients by using serial multisequence magnetic resonance imaging (MRI). Materials and Methods: Forty transient ischemic attack/stroke patients with ipsilateral <70% carotid stenosis underwent MRI of the plaque ipsilateral to the symptomatic side at baseline and after 1 year. The MRI protocol consisted of T1-weighted turbo field-echo, time-of-flight, T2-weighted turbo spin-echo (TSE), and pre- and postgadopentetate dimeglumine-enhanced T1-weighted TSE images. For each plaque, carotid lumen volume, wall volume, total vessel volume (=carotid lumen volume + wall volume), the presence of a lipid-rich necrotic core (LRNC), fibrous cap (FC) status, and the presence of intraplaque hemorrhage (IPH) were assessed at both time points. Results: Over a 1-year period, mean carotid lumen volume decreased with 4.8% +/- 2.0% (+/- standard error) (P = 0.013). Mean wall volume increased with 11.2% +/- 2.2% (P < 0.001). Total vessel volume did not significantly change (P = 0.147). At baseline, there were 18 plaques with a LRNC, which also had a LRNC at 1-year follow-up. No plaque without a LRNC at baseline developed a LRNC during the follow-up period. All plaques with a LRNC had a thin and/or ruptured FC at both time points. Twelve patients had IPH both at baseline and at follow-up. In one patient, IPH disappeared, whereas in another patient, new IPH appeared at follow-up. The presence of IPH and a LRNC with a thin and/or ruptured FC were not significantly associated with plaque progression (P > 0.05). Conclusions: In symptomatic patients with an ipsilateral carotid plaque causing <70% stenosis, we found evidence for inward plaque remodeling over a 1-year period. Overall, the presence/absence of IPH, a LRNC, and FC status did not change over 1 year. Show less
Westenberg, J.J.M.; Roos, A. de; Grotenhuis, H.B.; Steendijk, P.; Hendriksen, D.; Boogaard, P.J. van den; ... ; Reiber, J.H.C. 2010
Purpose: To evaluate the accuracy and reproducibility of aortic pulse wave velocity (PWV) assessment by in-plane velocity-encoded magnetic resonance imaging (MRI). Materials and Methods: In 14... Show morePurpose: To evaluate the accuracy and reproducibility of aortic pulse wave velocity (PWV) assessment by in-plane velocity-encoded magnetic resonance imaging (MRI). Materials and Methods: In 14 patients selected for cardiac catheterization on suspicion of coronary artery disease and 15 healthy volunteers, PWV was assessed with multislice two-directional in-plane velocity-encoded MRI (PWVi.p.) and compared with conventionally assessed PWV from multisite one-directional through-plane velocity-encoded MRI (PWVt.p.). In patients, PWV was also obtained from intraarterially acquired pressure-time curves (PWVpressure), which is considered the gold standard reference method. In volunteers, PWVi.p. and PWVt.p. were obtained in duplicate in the same examination to test reproducibility. Results: In patients, PWVi.p. showed stronger correlation and similar variation with PWVpressure than PWVt.p.). (Pearson correlation r = 0.75 vs. r = 0.58, and coefficient of variation [COV] = 10% vs. COV = 12%, respectively). In volunteers, repeated PWVi.p. assessment showed stronger correlation and less variation than repeated PWVt.p. (proximal aorta: r = 0.97 and COV = 10% vs. r = 0.69 and COV = 17%; distal aorta: r = 0.94 and COV = 12% vs. r = 0.90 and COV = 16%; total aorta: r = 0.97 and COV = 7% vs. r = 0.90 and COV = 13%). Conclusion: PWVi.p. is an improvement over conventional PWVt.p. by showing higher agreement as compared to the gold standard (PWVpressure) and higher reproducibility for repeated MRI assessment. Show less
Gupta, V.; Hendriks, E.A.; Milles, J.; Geest, R.J. van der; Jerosch-Herold, M.; Reiber, J.H.C.; Lelieveldt, B.P.F. 2010
Rationale and Objectives: Derivation of diagnostically relevant parameters from first-pass myocardial perfusion magnetic resonance images involves the tedious and time-consuming manual segmentation... Show moreRationale and Objectives: Derivation of diagnostically relevant parameters from first-pass myocardial perfusion magnetic resonance images involves the tedious and time-consuming manual segmentation of the myocardium in a large number of images. To reduce the manual interaction and expedite the perfusion analysis, we propose an automatic registration and segmentation method for the derivation of perfusion linked parameters. Materials and Methods: A complete automation was accomplished by first registering misaligned images using a method based on independent component analysis, and then using the registered data to automatically segment the myocardium with active appearance models. We used 18 perfusion studies (100 images per study) for validation in which the automatically obtained (AO) contours were compared with expert drawn contours on the basis of point-to-curve error, Dice index, and relative perfusion upslope in the myocardium. Results: Visual inspection revealed successful segmentation in 15 out of 18 studies. Comparison of the AO contours with expert drawn contours yielded 2.23 0.53 mm and 0.91 +/- 0.02 as point-to-curve error and Dice index, respectively. The average difference between manually and automatically obtained relative upslope parameters was found to be statistically insignificant (P = .37). Moreover, the analysis time per slice was reduced from 20 minutes (manual) to 1.5 minutes (automatic), Conclusion: We proposed an automatic method that significantly reduced the time required for analysis of first-pass cardiac magnetic resonance perfusion images. The robustness and accuracy of the proposed method were demonstrated by the high spatial correspondence and statistically insignificant difference in perfusion parameters, when AO contours were compared with expert drawn contours. Show less
Background: Calcitonin gene-related peptide (CGRP) plays a fundamental role in the pathophysiology of neurovascular headaches. CGRP infusion causes headache and dilation of cranial vessels. However... Show moreBackground: Calcitonin gene-related peptide (CGRP) plays a fundamental role in the pathophysiology of neurovascular headaches. CGRP infusion causes headache and dilation of cranial vessels. However, it is unknown to what extent CGRP-induced vasodilation contributes to immediate head pain and whether the migraine-specific abortive drug sumatriptan, a 5-hydroxytryptamine 1B/1D agonist, inhibits CGRP-induced immediate vasodilation and headache. Methods: We performed a double-blind, randomized, placebo-controlled, crossover study in 18 healthy volunteers. We recorded circumference changes of the middle meningeal artery (MMA) and middle cerebral artery (MCA) using magnetic resonance angiography before and after infusion (20 minutes) of 1.5 mu g/min human alpha CGRP or placebo (isotonic saline) as well as after a 6-mg sumatriptan subcutaneous injection. Results: Compared with placebo, CGRP caused significant dilation of MMA (p = 0.006) and no dilation of MCA (p = 0.69). Sumatriptan caused a marked contraction of MMA (15%-25.2%) and marginal contraction of MCA (3.9% to 5.3%). Explorative analysis revealed that sumatriptan had a more selective action on MMA compared with MCA on the CGRP day (p < 0.0001) and on the placebo day (p = 0.007). Conclusion: These data suggest that exogenous CGRP dilates extracranial vessels and not intracranial, and that sumatriptan exerts part of its antinociceptive action by constricting MMA and not MCA. Classification of evidence: This study provides Class I evidence that IV GCRP causes dilation of the MMA but not the MCA in healthy volunteers, and that sumatriptan reverses the dilation of the MMA caused by CGRP. Neurology (R) 2010;75:1520-1526 Show less
Taxis, C.F.B.V.H. van; Wijnmaalen, A.P.; Geest, R.J. van der; Schuijf, J.D.; Bax, J.J.; Schalij, M.J.; Zeppenfeld, K. 2010
Background: Magnetic resonance imaging (MRI) is sensitive to early atherosclerotic changes such as positive remodeling in patients with coronary artery disease (CAD). We assessed prevalence,... Show moreBackground: Magnetic resonance imaging (MRI) is sensitive to early atherosclerotic changes such as positive remodeling in patients with coronary artery disease (CAD). We assessed prevalence, quality, and extent of coronary atherosclerosis in a group of healthy subjects compared to patients with confirmed CAD. Methodology: Twenty-two patients with confirmed CAD (15M, 7F, mean age 60.4 +/- 10.4 years) and 26 healthy subjects without history of CAD (11M, 15F, mean age 56.1 +/- 4.4 years) underwent MRI of the right coronary artery (RCA) and vessel wall (MR-CVW) on a clinical 1.5T MR-scanner. Wall thickness measurements of both groups were compared. Principal Findings: Stenoses of the RCA (both < and >= 50% on CAG) were present in all patients. In 21/22 patients, stenoses detected at MRI corresponded to stenoses detected with conventional angiography. In 19/26 asymptomatic subjects, there was visible luminal narrowing in the MR luminography images. Fourteen of these subjects demonstrated corresponding increase in vessel wall thickness. In 4/26 asymptomatic subjects, vessel wall thickening without luminal narrowing was present. Maximum and mean wall thicknesses in patients were significantly higher (2.16 vs 1.92 mm, and 1.38 vs 1.22 mm, both p < 0.05). Conclusions: In this cohort of middle-aged individuals, both patients with stable angina and angiographically proven coronary artery disease, as well as age-matched asymptomatic subjects. exhibited coronary vessel wall thickening detectable with MR coronary vessel wall imaging. Maximum and mean wall thicknesses were significantly higher in patients. The vast majority of asymptomatic subjects had either positive remodeling without luminal narrowing, or non-significant stenosis. Show less
OBJECTIVE:: To investigate the natural course of carotid plaque progression in transient ischemic attack/stroke patients by using serial multisequence magnetic resonance imaging (MRI). MATERIALS... Show moreOBJECTIVE:: To investigate the natural course of carotid plaque progression in transient ischemic attack/stroke patients by using serial multisequence magnetic resonance imaging (MRI). MATERIALS AND METHODS:: Forty transient ischemic attack/stroke patients with ipsilateral <70% carotid stenosis underwent MRI of the plaque ipsilateral to the symptomatic side at baseline and after 1 year. The MRI protocol consisted of T1-weighted turbo field-echo, time-of-flight, T2-weighted turbo spin-echo (TSE), and pre- and postgadopentetate dimeglumine-enhanced T1-weighted TSE images. For each plaque, carotid lumen volume, wall volume, total vessel volume (=carotid lumen volume + wall volume), the presence of a lipid-rich necrotic core (LRNC), fibrous cap (FC) status, and the presence of intraplaque hemorrhage (IPH) were assessed at both time points. RESULTS:: Over a 1-year period, mean carotid lumen volume decreased with 4.8% ± 2.0% (±standard error) (P = 0.013). Mean wall volume increased with 11.2% ± 2.2% (P < 0.001). Total vessel volume did not significantly change (P = 0.147). At baseline, there were 18 plaques with a LRNC, which also had a LRNC at 1-year follow-up. No plaque without a LRNC at baseline developed a LRNC during the follow-up period. All plaques with a LRNC had a thin and/or ruptured FC at both time points. Twelve patients had IPH both at baseline and at follow-up. In one patient, IPH disappeared, whereas in another patient, new IPH appeared at follow-up. The presence of IPH and a LRNC with a thin and/or ruptured FC were not significantly associated with plaque progression (P > 0.05). CONCLUSIONS:: In symptomatic patients with an ipsilateral carotid plaque causing <70% stenosis, we found evidence for inward plaque remodeling over a 1-year period. Overall, the presence/absence of IPH, a LRNC, and FC status did not change over 1 year. Show less
