Einar Heiberg

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2003 Index IEEE Transactions on Visualization and Computer Graphics Vol. 9

Abstract This index covers all technical items-papers, correspondence, reviews, etc.-that appeare... more Abstract This index covers all technical items-papers, correspondence, reviews, etc.-that appeared in this periodical during the year, and items from previous years that were commented upon or corrected in this year. Departments and other items may also be covered if they have been judged to have archival value. The Author Index contains the primary entry for each item, listed under the first author&amp;#x27;s name. The primary entry includes the coauthors&amp;#x27; names, the title of the paper or other item, and its location, specified by the ...

Author index Volume 25

1017 Computer-assisted calculation of myocardial infarct size shortens the evaluation time of contrast enhanced cardiac MRI

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Intracardiac cardiovascular magnetic resonance velocity mapping: comparison of kt BLAST and SENSE accelerated 4D acquisitions with 2D-flow at 1.5 T and 3 T

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Validation of an algorithm for left ventricular segmentation in 150 patients shows potential for further development towards fully automatic segmentation

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Infarct size is overestimated by contrast-enhanced CMR in the acute phase but not at 7 days when compared with histopathology

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An improved segmentation algorithm for quantification of myocardial infarction in contrast enhanced CMR images-validated in ex-vivo studies

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These abstracts have been selected for VIEWING only as ePosters and in print. ePosters will be available on Screen A & B throughout the meeting, Print Posters at the times indicated below. Please refer to the PROGRAM for more details

Validation and Development of a New Automatic Algorithm for Time-Resolved Segmentation of the Left Ventricle in Magnetic Resonance Imaging

Introduction. Manual delineation of the left ventricle is clinical standard for quantification of... more Introduction. Manual delineation of the left ventricle is clinical standard for quantification of cardiovascular magnetic resonance images despite being time consuming and observer dependent. Previous automatic methods generally do not account for one major contributor to stroke volume, the long-axis motion. Therefore, the aim of this study was to develop and validate an automatic algorithm for time-resolved segmentation covering the whole left ventricle, including basal slices affected by long-axis motion. Methods. Ninety subjects imaged with a cine balanced steady state free precession sequence were included in the study (training set = 40, test set = 50). Manual delineation was reference standard and second observer analysis was performed in a subset ( = 25). The automatic algorithm uses deformable model with expectation-maximization, followed by automatic removal of papillary muscles and detection of the outflow tract. Results. The mean differences between automatic segmentation and manual delineation were EDV −11 mL, ESV 1 mL, EF −3%, and LVM 4 g in the test set. Conclusions. The automatic LV segmentation algorithm reached accuracy comparable to interobserver for manual delineation, thereby bringing automatic segmentation one step closer to clinical routine. The algorithm and all images with manual delineations are available for benchmarking.

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A new validated T2* analysis method with certainty estimates for cardiac and liver iron load determination

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Whole-heart 4D flow can be acquired with preserved quality without respiratory gating facilitating clinical use

A novel tool for phase contrast MR-derived pulse wave velocity measurement-validation against applanation tonometry and phantom studies

Vortex ring mixing in the left ventricle of the human heart

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Rationale and design of the'MITOCARE'Study: a phase II, multicenter, randomized, double-blind, placebo-controlled study to assess the safety and efficacy of TRO40303 for the reduction of reperfusion injury in patients undergoing percutaneous coronary intervention for acute myocardial infarction

Vortex ring formation in the left ventricle of the heart: analysis by 4D flow MRI and Lagrangian coherent structures

Recent studies suggest that vortex ring formation during left ventricular (LV) rapid filling is a... more Recent studies suggest that vortex ring formation during left ventricular (LV) rapid filling is an optimized mechanism for blood transport, and that the volume of the vortex ring is an important measure. However, due to lack of quantitative methods, the volume of the vortex ring has not previously been studied. Lagrangian Coherent Structures (LCS) is a new flow analysis method, which enables in vivo quantification of vortex ring volume. Therefore, we aimed to investigate if vortex ring volume in the human LV can be reliably quantified using LCS and magnetic resonance velocity mapping (4D PC-MR). Flow velocities were measured using 4D PC-MR in nine healthy volunteers and four patients with dilated ischemic cardiomyopathy. LV LCS were computed from flow velocities and manually delineated in all subjects. Vortex volume in the healthy volunteers was 51 ± 6% of the left ventricular volume, and 21 ± 5% in the patients. Interobserver variability was -1 ± 13% and interstudy variability was -2 ± 12%. Compared to idealized flow experiments, the vortex rings showed additional complexity and asymmetry, related to endocardial trabeculation and papillary muscles. In conclusion, LCS and 4D PC-MR enables measurement of vortex ring volume during rapid filling of the LV.

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Quantification and visualization of cardiovascular 4D velocity mapping accelerated with parallel imaging or kt BLAST: head to head comparison and validation at 1.5 T …

Journal of …, 2011

BackgroundThree-dimensional time-resolved (4D) phase-contrast (PC) CMR can visualize and quantify... more BackgroundThree-dimensional time-resolved (4D) phase-contrast (PC) CMR can visualize and quantify cardiovascular flow but is hampered by long acquisition times. Acceleration with SENSE or k-t BLAST are two possibilities but results on validation are lacking, especially at 3 T. The aim of this study was therefore to validate quantitative in vivo cardiac 4D-acquisitions accelerated with parallel imaging and k-t BLAST at 1.5 T and 3 T with 2D-flow as the reference and to investigate if field strengths and type of acceleration have major effects on intracardiac flow visualization.MethodsThe local ethical committee approved the study. 13 healthy volunteers were scanned at both 1.5 T and 3 T in random order with 2D-flow of the aorta and main pulmonary artery and two 4D-flow sequences of the heart accelerated with SENSE and k-t BLAST respectively. 2D-image planes were reconstructed at the aortic and pulmonary outflow. Flow curves were calculated and peak flows and stroke volumes (SV) compared to the results from 2D-flow acquisitions. Intra-cardiac flow was visualized using particle tracing and image quality based on the flow patterns of the particles was graded using a four-point scale.ResultsGood accuracy of SV quantification was found using 3 T 4D-SENSE (r2 = 0.86, -0.7 ± 7.6%) and although a larger bias was found on 1.5 T (r2 = 0.71, -3.6 ± 14.8%), the difference was not significant (p = 0.46). Accuracy of 4D k-t BLAST for SV was lower (p < 0.01) on 1.5 T (r2 = 0.65, -15.6 ± 13.7%) compared to 3 T (r2 = 0.64, -4.6 ± 10.0%). Peak flow was lower with 4D-SENSE at both 3 T and 1.5 T compared to 2D-flow (p < 0.01) and even lower with 4D k-t BLAST at both scanners (p < 0.01). Intracardiac flow visualization did not differ between 1.5 T and 3 T (p = 0.09) or between 4D-SENSE or 4D k-t BLAST (p = 0.85).ConclusionsThe present study showed that quantitative 4D flow accelerated with SENSE has good accuracy at 3 T and compares favourably to 1.5 T. 4D flow accelerated with k-t BLAST underestimate flow velocities and thereby yield too high bias for intra-cardiac quantitative in vivo use at the present time. For intra-cardiac 4D-flow visualization, however, 1.5 T and 3 T as well as SENSE or k-t BLAST can be used with similar quality.

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Development of an automated method for display of ischemic myocardium from simulated electrocardiograms

Journal of …, 2009

Development of an automated method for display of ischemic myocardium from simulated electrocardi... more

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Rapid short-duration hypothermia with cold saline and endovascular cooling before reperfusion reduces microvascular obstruction and myocardial infarct size

BMC cardiovascular …, 2008

The aim of this study was to evaluate the combination of a rapid intravenous infusion of cold sal... more

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Development and validation of a new automatic algorithm for quantification of left ventricular volumes and function in gated myocardial perfusion SPECT using cardiac …

Journal of Nuclear …, 2011

Background. By gating image acquisition in myocardial perfusion SPECT (MPS) to ECG, left ventricu... more Background. By gating image acquisition in myocardial perfusion SPECT (MPS) to ECG, left ventricular (LV) volumes and function can be determined. Several previous studies have shown that existing MPS software packages underestimate LV volumes compared to cardiac magnetic resonance (CMR). The aim of this study was therefore to develop a new LV segmentation algorithm for gated MPS using CMR as reference standard.

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Feasibility of patient specific aortic blood flow CFD simulation

… Image Computing and …, 2006

Patient specific modelling of the blood flow through the human aorta is performed using computati... more Patient specific modelling of the blood flow through the human aorta is performed using computational fluid dynamics (CFD) and magnetic resonance imaging (MRI). Velocity patterns are compared between computer simulations and measurements. The workflow includes several steps: MRI measurement to obtain both geometry and velocity, an automatic levelset segmentation followed by meshing of the geometrical model and CFD setup to perform the simulations follwed by the actual simulations. The computational results agree well with the measured data.

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