Kowallick, Johannes Tammo

[["dc.bibliographiccitation.firstpage","206"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","Journal of magnetic resonance imaging : JMRI"],["dc.bibliographiccitation.lastpage","213"],["dc.bibliographiccitation.volume","40"],["dc.contributor.author","Joseph, Arun"],["dc.contributor.author","Kowallick, Johannes T."],["dc.contributor.author","Merboldt, Klaus-Dietmar"],["dc.contributor.author","Voit, Dirk"],["dc.contributor.author","Schaetz, Sebastian"],["dc.contributor.author","Zhang, Shuo"],["dc.contributor.author","Sohns, Jan M."],["dc.contributor.author","Lotz, Joachim"],["dc.contributor.author","Frahm, Jens"],["dc.date.accessioned","2019-07-09T11:41:30Z"],["dc.date.available","2019-07-09T11:41:30Z"],["dc.date.issued","2014-07-01"],["dc.description.abstract","PURPOSE: To evaluate a novel real-time phase-contrast magnetic resonance imaging (MRI) technique for the assessment of through-plane flow in the ascending aorta. MATERIALS AND METHODS: Real-time MRI was based on a radial fast low-angle shot (FLASH) sequence with about 30-fold undersampling and image reconstruction by regularized nonlinear inversion. Phase-contrast maps were obtained from two (interleaved or sequential) acquisitions with and without a bipolar velocity-encoding gradient. Blood flow in the ascending aorta was studied in 10 healthy volunteers at 3 T by both real-time MRI (15 sec during free breathing) and electrocardiogram (ECG)-synchronized cine MRI (with and without breath holding). Flow velocities and stroke volumes were evaluated using standard postprocessing software. RESULTS: The total acquisition time for a pair of phase-contrast images was 40.0 msec (TR/TE = 2.86/1.93 msec, 10° flip angle, 7 spokes per image) for a nominal in-plane resolution of 1.3 mm and a section thickness of 6 mm. Quantitative evaluations of spatially averaged flow velocities and stroke volumes were comparable for real-time and cine methods when real-time MRI data were averaged across heartbeats. For individual heartbeats real-time phase-contrast MRI resulted in higher peak velocities for values above 120 cm s(-1). CONCLUSION: Real-time phase-contrast MRI of blood flow in the human aorta yields functional parameters for individual heartbeats. When averaged across heartbeats real-time flow velocities and stroke volumes are comparable to values obtained by conventional cine MRI."],["dc.identifier.doi","10.1002/jmri.24328"],["dc.identifier.fs","605197"],["dc.identifier.pmid","24123295"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/12139"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/58445"],["dc.language.iso","en"],["dc.notes.intern","Merged from goescholar"],["dc.relation.issn","1522-2586"],["dc.rights","CC BY-NC 4.0"],["dc.rights.uri","https://creativecommons.org/licenses/by-nc/4.0"],["dc.subject.mesh","Adult"],["dc.subject.mesh","Algorithms"],["dc.subject.mesh","Aorta"],["dc.subject.mesh","Blood Flow Velocity"],["dc.subject.mesh","Computer Systems"],["dc.subject.mesh","Humans"],["dc.subject.mesh","Image Enhancement"],["dc.subject.mesh","Image Interpretation, Computer-Assisted"],["dc.subject.mesh","Magnetic Resonance Angiography"],["dc.subject.mesh","Magnetic Resonance Imaging, Cine"],["dc.subject.mesh","Male"],["dc.subject.mesh","Reproducibility of Results"],["dc.subject.mesh","Rheology"],["dc.subject.mesh","Sensitivity and Specificity"],["dc.subject.mesh","Young Adult"],["dc.title","Real-time flow MRI of the aorta at a resolution of 40 msec."],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.issue","S1"],["dc.bibliographiccitation.journal","Journal of Cardiovascular Magnetic Resonance"],["dc.bibliographiccitation.volume","15"],["dc.contributor.author","Lotz, Joachim"],["dc.contributor.author","Sohns, Jan Martin"],["dc.contributor.author","Steinmetz, Michael"],["dc.contributor.author","Kowallick, Johannes Tammo"],["dc.contributor.author","Schulte, Christina"],["dc.contributor.author","Staab, Wieland"],["dc.contributor.author","Joseph, Arun A."],["dc.contributor.author","Merboldt, Klaus-Dietmar"],["dc.contributor.author","Voit, Dirk"],["dc.contributor.author","Zhang, Shuo"],["dc.contributor.author","Uecker, Martin"],["dc.contributor.author","Unterberg-Buchwald, Christina"],["dc.contributor.author","Hasenfuss, Gerd"],["dc.contributor.author","Frahm, Jens"],["dc.date.accessioned","2020-05-13T13:46:20Z"],["dc.date.available","2020-05-13T13:46:20Z"],["dc.date.issued","2013"],["dc.description.abstract","Background A new MRI technology for real-time MRI at high temporal and high spatial resolution was applied to CMR. First clinical applications cover dynamic imaging of wall motion and volume changes during cardiac arrhythmias as well as quantitative flow measurements under physiologic stress maneuvers. Methods A recently introduced real-time MRI method based on undersampled radial FLASH sequences with image reconstruction by regularized nonlinear inversion was applied to CMR. Anatomical imaging in real time was performed at 34 ms temporal resolution (30 fps) using 1.5 mm in-plane resolution and 6 mm slice thickness. Real-time quantitative flow measurements employed two acquisitions at 20 ms resolution, yielding a temporal resolution of 40 ms (25 fps) at 1.3 mm in-plane resolution and 6 mm slice thickness. Healthy volunteers as well as patients with arrhythmia were examined in a clinical 3T MR scanner. The image series were analyzed using a modified standard software capable of dealing with 100 to 900 images per slice position. The ECG signal was co-registered for documentation and ease of image analysis. Results The new high-resolution real-time MRI technique was used to analyze the beat-to-beat variability of patients with arrhythmia and to define ejection fractions in normal and arrhythmic episodes. Quantitative flow measurements were obtained in all major intrathoracic vessels during free breathing. Specific measurements during increased (Valsalva maneouver) and reduced intrathoracic pressure (Mueller maneouver) were obtained in healthy volunteers to document cardiovascular response to physiologic stressors. Regional wall motion, ventricular volumes, myocardial mass and ejection fraction were derived including standard deviations based on temporal variability of the heart cycle. Suitable software strategies for the analysis of the large datasets are indispensible to bring real-time CMR into clinical routine. Conclusions Real-time CMR with high temporal and high spatial resolution emerges as a promising tool for future clinical studies."],["dc.identifier.doi","10.1186/1532-429X-15-S1-E99"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/8915"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/65379"],["dc.language.iso","en"],["dc.notes.intern","Merged from goescholar"],["dc.relation.issn","1532-429X"],["dc.rights","Goescholar"],["dc.rights.uri","https://goescholar.uni-goettingen.de/licenses"],["dc.title","High resolution real-time CMR of function and flow: initial clinical results"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]