Sohns, Jan Martin

[["dc.bibliographiccitation.firstpage","1066"],["dc.bibliographiccitation.issue","10"],["dc.bibliographiccitation.journal","Clinical Radiology"],["dc.bibliographiccitation.lastpage","1071"],["dc.bibliographiccitation.volume","69"],["dc.contributor.author","Fasshauer, Martin"],["dc.contributor.author","Joseph, Arun A."],["dc.contributor.author","Kowallick, Johannes Tammo"],["dc.contributor.author","Unterberg-Buchwald, Christine"],["dc.contributor.author","Merboldt, Klaus-Dietmar"],["dc.contributor.author","Voit, Dirk"],["dc.contributor.author","Steinmetz, M."],["dc.contributor.author","Staab, Wieland"],["dc.contributor.author","Schaetz, S."],["dc.contributor.author","Zhang, S."],["dc.contributor.author","Frahm, Jens"],["dc.contributor.author","Lotz, Joachim"],["dc.contributor.author","Sohns, J. M."],["dc.date.accessioned","2018-11-07T09:34:30Z"],["dc.date.available","2018-11-07T09:34:30Z"],["dc.date.issued","2014"],["dc.description.abstract","AIM: To evaluate the potential of real-time phase-contrast flow magnetic resonance imaging (MRI) at 40 ms resolution for the simultaneous determination of blood flow in the ascending aorta (AA) and superior vena cava (SVC) in response to reduced intrathoracic pressure (Mueller manoeuvre). MATERIALS AND METHODS: Through-plane flow was assessed in 20 healthy young subjects using real-time phase-contrast MRI based on highly undersampled radial fast low-angle shot (FLASH) with image reconstruction by regularized non-linear inversion. Haemodynamic alterations (three repetitions per subject = 60 events) were evaluated during normal breathing (10 s), inhalation with nearly closed epiglottis (10 s), and recovery (20 s). RESULTS: Relative to normal breathing and despite interindividual differences, reduced intrathoracic pressure by at least 30 mmHg significantly decreased the initial peak mean velocity (averaged across the lumen) in the AA by -24 +/- 9% and increased the velocity in the SVC by +28 +/- 25% (p < 0.0001, n = 23 successful events). Respective changes in flow volume per heartbeat were -25 +/- 9% in the AA and +49 +/- 44% in the SVC (p < 0.0001, n = 23). Flow parameters returned to baseline during sustained pressure reduction, while the heart rate was elevated by 10% (p < 0.0001) after the start (n = 24) and end (n = 17) of the manoeuvre. CONCLUSIONS: Real-time flow MRI during low intrathoracic pressure non-invasively revealed quantitative haemodynamic adjustments in both the AA and SVC. (C) 2014 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved."],["dc.description.sponsorship","DFG [LO 1773/1]"],["dc.identifier.doi","10.1016/j.crad.2014.06.004"],["dc.identifier.isi","000342881800013"],["dc.identifier.pmid","25060931"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/32184"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","W B Saunders Co Ltd"],["dc.relation.issn","1365-229X"],["dc.relation.issn","0009-9260"],["dc.title","Real-time phase-contrast flow MRI of haemodynamic changes in the ascending aorta and superior vena cava during Mueller manoeuvre"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","1"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","The Open Medical Imaging Journal"],["dc.bibliographiccitation.lastpage","5"],["dc.bibliographiccitation.volume","8"],["dc.contributor.author","Frahm, Jens"],["dc.contributor.author","Schätz, Sebastian"],["dc.contributor.author","Untenberger, Markus"],["dc.contributor.author","Zhang, Shuo"],["dc.contributor.author","Voit, Dirk"],["dc.contributor.author","Merboldt, Klaus-Dietmar"],["dc.contributor.author","Sohns, Jan Martin"],["dc.contributor.author","Lotz, Joachim"],["dc.contributor.author","Uecker, Martin"],["dc.date.accessioned","2017-09-07T11:54:24Z"],["dc.date.available","2017-09-07T11:54:24Z"],["dc.date.issued","2014"],["dc.identifier.doi","10.2174/1874347101408010001"],["dc.identifier.gro","3145160"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/2865"],["dc.notes.intern","Crossref Import"],["dc.notes.status","public"],["dc.publisher","Bentham Science Publishers Ltd."],["dc.relation.issn","1874-3471"],["dc.title","On the Temporal Fidelity of Nonlinear Inverse Reconstructions for Real- Time MRI – The Motion Challenge"],["dc.type","journal_article"],["dc.type.internalPublication","unknown"],["dc.type.peerReviewed","no"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","20140401"],["dc.bibliographiccitation.issue","1042"],["dc.bibliographiccitation.journal","British Journal of Radiology"],["dc.bibliographiccitation.volume","87"],["dc.contributor.author","Kowallick, Johannes Tammo"],["dc.contributor.author","Joseph, Arun A."],["dc.contributor.author","Unterberg-Buchwald, Christine"],["dc.contributor.author","Fasshauer, Martin"],["dc.contributor.author","van Wijk, K."],["dc.contributor.author","Merboldt, Klaus-Dietmar"],["dc.contributor.author","Voit, Dirk"],["dc.contributor.author","Frahm, Jens"],["dc.contributor.author","Lotz, Joachim"],["dc.contributor.author","Sohns, J. M."],["dc.date.accessioned","2018-11-07T09:34:40Z"],["dc.date.available","2018-11-07T09:34:40Z"],["dc.date.issued","2014"],["dc.description.abstract","Objective: Real-time phase-contrast flow MRI at high spatiotemporal resolution was applied to simultaneously evaluate haemodynamic functions in the ascending aorta (AA) and superior vena cava (SVC) during elevated intrathoracic pressure (Valsalva manoeuvre). Methods: Real-time phase-contrast flow MRI at 3 T was based on highly undersampled radial gradient-echo acquisitions and phase-sensitive image reconstructions by regularized non-linear inversion. Dynamic alterations of flow parameters were obtained for 19 subjects at 40-ms temporal resolution, 1.33-mm in-plane resolution and 6-mm section thickness. Real-time measurements were performed during normal breathing (10 s), increased intrathoracic pressure (10 s) and recovery (20 s). Results: Real-time measurements were technically successful in all volunteers. During the Valsalva manoeuvre (late strain) and relative to values during normal breathing, the mean peak flow velocity and flow volume decreased significantly in both vessels (p < 0.001) followed by a return to normal parameters within the first 10 s of recovery in the AA. By contrast, flow in the SVC presented with a brief (1-2 heartbeats) but strong overshoot of both the peak velocity and blood volume immediately after pressure release followed by rapid normalization. Conclusion: Real-time phase-contrast flow MRI may assess cardiac haemodynamics non-invasively, in multiple vessels, across the entire luminal area and at high temporal and spatial resolution. Advances in knowledge: Future clinical applications of this technique promise new insights into haemodynamic alterations associated with pre-clinical congestive heart failure or diastolic dysfunction, especially in cases where echocardiography is technically compromised."],["dc.description.sponsorship","DFG [LO 1773/1-1]"],["dc.identifier.doi","10.1259/bjr.20140401"],["dc.identifier.isi","000342620300018"],["dc.identifier.pmid","25074791"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/32222"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","British Inst Radiology"],["dc.relation.issn","1748-880X"],["dc.relation.issn","0007-1285"],["dc.title","Real-time phase-contrast flow MRI of the ascending aorta and superior vena cava as a function of intrathoracic pressure (Valsalva manoeuvre)"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.issue","S1"],["dc.bibliographiccitation.journal","Journal of Cardiovascular Magnetic Resonance"],["dc.bibliographiccitation.volume","15"],["dc.contributor.author","Sohns, Jan Martin"],["dc.contributor.author","Unterberg-Buchwald, Christina"],["dc.contributor.author","Kowallick, Johannes Tammo"],["dc.contributor.author","Steinmetz, Michael"],["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","Frahm, Jens"],["dc.contributor.author","Lotz, Joachim"],["dc.date.accessioned","2020-05-13T13:46:13Z"],["dc.date.available","2020-05-13T13:46:13Z"],["dc.date.issued","2013"],["dc.description.abstract","Background A high resolution real-time phase-contrast MRI flow technique was used to measure flow dynamics in the ascending aorta as well as superior vena cava. MRI technique based on undersampled radial fast low-angle shot acquisitions with phase-sensitive image reconstructions by regularized nonlinear inversion. Normal flow values as well as flow measurements during physiologic stress tests like Valsalva (increased intrathoracic pressure) and Mueller (decreased intrathoracic pressure, reverse of Valsalva maneuver) were obtained in healthy volunteers. Methods Blood flow was measured in the ascending aorta and superior vena cava using a single scan plane perpendicular to the ascending aorta at the level of the right pulmonary artery. In-plane resolution of 1.8 mm, section thickness of 6 mm at a real-time resolution of 48 ms was achieved by TR 3.44 ms; TE 2.76 ms; flip angle, 10 degrees and seven radial spokes per image. Scans were done in a clinical 3T scanner. ECG was co-registered for documentation only. Realtime scans were done for 20 seconds in normal measurements, 30 seconds for physiologic and stress maneuvers - 10 seconds normal breathing, 10 seconds applied stress, 10 seconds recovery time. Image analysis was done using a specifically modified prototype software Qflow by Medis, NL. Results Realtime measurements were successful in all cases. We observed a decrease of blood-flow during Valsalva and Mueller maneuver in the ascending aorta. At the beginning of the maneuver, the blood flow increased under both increased and reduced intrathoracic pressure, followed by a continuous period of nearly 20 sec of decreased flow. A reactive hyperdynamic flow response was detected after restarting regular breathing. Conclusions High resolution real-time MRI flow measurements are able to resolve detailed physiological blood flow changes during Vasalva and Mueller maneuvers with high reliability. The results are in consistence with published echocardiography studies on Valsalva and Mueller maneuvers. Free breathing and patient's movement did not disturb the scan and image quality with this new technique. This technique might provide new insights into pathophysiologic changes associated for example with preclinical congestive heart failure."],["dc.identifier.doi","10.1186/1532-429X-15-S1-E17"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/65378"],["dc.language.iso","en"],["dc.relation.issn","1532-429X"],["dc.title","Real-time cardiac phase contrast MRI blood flow including Valsalva and Mueller maneuver. Initial experiences"],["dc.type","journal_article"],["dc.type.internalPublication","unknown"],["dspace.entity.type","Publication"]]