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Flow‐sensitive 4D MRI of the thoracic aorta: Comparison of image quality, quantitative flow, and wall parameters at 1.5 T and 3 T
Author(s) -
Strecker Christoph,
Harloff Andreas,
Wallis Wolf,
Markl Michael
Publication year - 2012
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.23735
Subject(s) - cardiac cycle , medicine , image quality , magnetic resonance imaging , blood flow , lumen (anatomy) , aorta , thoracic aorta , magnetic resonance angiography , hemodynamics , nuclear medicine , flow velocity , biomedical engineering , radiology , cardiology , image (mathematics) , computer science , artificial intelligence , relaxation (psychology)
Purpose: To evaluate the effect of field strength on flow‐sensitive 4D magnetic resonance imaging (MRI) of the thoracic aorta. A volunteer study at 1.5 T and 3 T was conducted to compare phase‐contrast MR angiography (MRA) and 3D flow visualization quality as well as quantification of aortic hemodynamics. Materials and Methods: Ten healthy volunteers were examined by flow‐sensitive 4D MRI at both 1.5 T and 3 T MRI with identical imaging parameters (TE/TR = 6/5.1 msec, spatial/temporal resolution ≈2 mm/40.8 msec). Analysis included assessment of image quality of derived aortic 3D phase contrast (PC) angiography and 3D flow visualization (semiquantitative grading on a 0–2 scale, two blinded observers) and quantification of blood flow velocities, net flow per cardiac cycle, wall shear stress (WSS), and velocity noise. Results: Quality of 3D blood flow visualization (average grading = 1.8 ± 0.4 at 3 T vs. 1.1 ± 0.7 at 1.5 T) and the depiction of aortic lumen geometry by 3D PC‐MRA (1.7 ± 0.5 vs. 1.2 ± 0.6) were significantly ( P < 0.01) improved at 3 T while velocity noise was significantly higher ( P < 0.01) at 1.5 T. Velocity quantification resulted in minimally altered (0.05 m/s, 3 mL/cycle and 0.01 N/m 2 ) but not statistically different ( P = 0.40, P = 0.39, and P = 0.82) systolic peak velocities, net flow, and WSS for 1.5 T compared to 3 T. Conclusion: Flow‐sensitive 4D MRI at 3 T provided improved image quality without additional artifacts related to higher fields. Imaging at 1.5 T MRI, which is more widely available, was also feasible and provided information on aortic 3D hemodynamics of moderate quality with identical performance regarding quantitative analysis. J. Magn. Reson. Imaging 2012;36:1097–1103. © 2012 Wiley Periodicals, Inc.