Time-resolved magnetic resonance angiography and flow-sensitive 4-dimensional magnetic resonance imaging at 3 Tesla for blood flow and wall shear stress analysis

• Published in: The Journal of thoracic and cardiovascular surgery Vol. 136; no. 2; pp. 400 - 407
• Main Authors: Frydrychowicz, Alex, MD, Berger, Alexander, Russe, Maximilan F, Stalder, Aurélien F., MS, Harloff, Andreas, MD, Dittrich, Sven, MD, Hennig, Jürgen, PhD, Langer, Mathias, MD, MBA, Markl, Michael, PhD
• Format: Journal Article
• Language: English
• Published: Philadelphia, PA Elsevier Inc 01.08.2008; AATS/WTSA; Elsevier
• Subjects: Adolescent; Adult; Aged; Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Aorta - physiology; Aorta - physiopathology; Aortic Valve Stenosis - physiopathology; Aortic Valve Stenosis - surgery; Biological and medical sciences; Blood Flow Velocity; Cardiology. Vascular system; Cardiothoracic Surgery; Cardiovascular system; Contrast Media; Female; Humans; Imaging, Three-Dimensional; Investigative techniques, diagnostic techniques (general aspects); Magnetic Resonance Angiography; Male; Medical sciences; Pneumology; Radiodiagnosis. Nmr imagery. Nmr spectrometry; Shear Strength; 3 dimensional; 4 dimensional; magnetic resonance imaging; OSI; oscillatory shear index; 26; MRI; CE-MRA; AAo; 4D; 3D; DAo; T; WSS; descending aorta; wall shear stress; Tesla; contrast-enhanced magnetic resonance angiography; ascending aorta; Wall; Analysis; Shear stress; Medical imagery; Anesthesia; Time; Circulatory system; Hemodynamics; NMR angiography; Cardiology; Nuclear magnetic resonance imaging; Blood flow
• ISSN: 0022-5223; 1097-685X
• DOI: 10.1016/j.jtcvs.2008.02.062

Objectives In light of the ongoing discussion about flow-mediated arterial remodeling, it was the aim of this report to demonstrate the detailed assessment of 3-dimensional vascular hemodynamics by high-field magnetic resonance imaging in healthy volunteers and to illustrate its potential in comparison with results in a patient with stenosis. Materials and Methods All examinations consisted of flow-sensitive 4-dimensional magnetic resonance imaging at 3 Tesla. Retrospective blood flow visualization and segmental quantification of wall shear stress and oscillatory shear index were performed. The results from 11 healthy individuals were compared with a 13-year-old patient with aortic stenosis who received a combined protocol with time-resolved 3-dimensional magnetic resonance angiography before and 5 and 9 months after intervention. Results Evaluation of normal blood flow characteristics demonstrated predominantly right-handed helical flow in the ascending aorta. Vortex formation was observed in 1 of 11 volunteers. Consistently high segmental wall shear stress was found along the circumference of the ascending aorta (average wall shear stress = 0.191 ± 0.06 N/m2 ) and descending aorta (average 0.191 ± 0.06 N/m2 ). Compared with volunteers, the patient revealed substantial flow changes proximal and distal to the stenosis. Blood flow alterations in the ascending aorta were also observed associated with changes in velocities and wall shear stress that gradually normalized after intervention. Conclusion Flow-sensitive 4-dimensional magnetic resonance imaging at 3 Tesla can provide deeper insights into hemodynamic alterations in the diagnosis and follow-up of aortic pathologies. These findings indicate the potential of the methodology for the evaluation of effects of localized pathologies on the entire vascular system, which will have to be confirmed in future studies.