Stephanie Wiesemann1,2, Sebastian Schmitter3, Aylin Demir1, Marcel Prothmann1, Carsten Schwenke4, Ashish Chawla5, Florian von Knobelsdorff-Brenkenhoff1,6, Andreas Greiser7, Ning Jin8, Emilie Bollache9, Michael Markl10, Jeanette Schulz-Menger1,2. 1. Department of Cardiology and Nephrology, Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max-Delbrueck Center for Molecular Medicine and HELIOS Hospital Berlin Buch, Berlin, Germany. 2. DZHK (German Center for Cardiovascular Research), partner site Berlin, Berlin, Germany. 3. Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany. 4. SCO:SSIS Statistical Consulting, Berlin, Germany. 5. Khoo Teck Puat Hospital, Yishun Central, Singapore, Singapore. 6. Clinic Agatharied, Department of Cardiology, Ludwig-Maximilians-University Munich, Hausham, Germany. 7. Siemens Healthcare, Erlangen, Germany. 8. Siemens Medical Solutions, Columbus, Ohio, USA. 9. Sorbonne Université, CNRS, INSERM, Laboratoire d'Imagerie Biomédicale, LIB, Paris, France. 10. Department of Radiology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois, USA.
Abstract
PURPOSE: 4D flow magnetic resonance imaging (4D-MRI) allows time-resolved visualization of blood flow patterns, quantification of volumes, velocities, and advanced parameters, such as wall shear stress (WSS). As 4D-MRI enters the clinical arena, standardization and awareness of confounders are important. Our aim was to evaluate the equivalence of 4D flow-derived aortic hemodynamics in healthy volunteers using different sequences and field strengths. METHODS: 4D-MRI was acquired in 10 healthy volunteers at 1.5T using three different prototype sequences, at 3T and at 7T (Siemens Healthineers). After evaluation of diagnostic quality in three segments (ascending-, descending aorta, aortic arch), peak velocity, flow volumes, and WSS were investigated. Equivalence limits for comparison of field strengths/sequences were based on the limits of Bland-Altman analyses of the intraobserver variability. RESULTS: Non-diagnostic quality was found in 10/144 segments, 9/10 were obtained at 7T. Apart for the comparison of forward flow between sequence 1 and 3, the differences in measurements between field strengths/sequences exceeded the range of agreement. Significant differences were found between field strengths/sequences for forward flow (1.5T vs. 3T, 3T vs. 7T, sequence 1 vs. 3, 2 vs. 3 [P < .001]), WSS (1.5T vs. 3T [P < .05], sequence 1 vs. 2, 1 vs. 3, 2 vs. 3 [P < .001]), and peak velocity (1.5T vs. 7T, sequence 1 vs. 3 [P > .001]). All parameters at all field strengths/with all sequences correlated moderately to strongly (r ≥ 0.5). CONCLUSION: Data from all sequences could be acquired and resulting images showed sufficient quality for further analysis. However, the variability of the measurements of peak velocity, flow volumes, and WSS was higher when comparing field strengths/sequences as the equivalence limits defined by the intraobserver assessments.
PURPOSE: 4D flow magnetic resonance imaging (4D-MRI) allows time-resolved visualization of blood flow patterns, quantification of volumes, velocities, and advanced parameters, such as wall shear stress (WSS). As 4D-MRI enters the clinical arena, standardization and awareness of confounders are important. Our aim was to evaluate the equivalence of 4D flow-derived aortic hemodynamics in healthy volunteers using different sequences and field strengths. METHODS: 4D-MRI was acquired in 10 healthy volunteers at 1.5T using three different prototype sequences, at 3T and at 7T (Siemens Healthineers). After evaluation of diagnostic quality in three segments (ascending-, descending aorta, aortic arch), peak velocity, flow volumes, and WSS were investigated. Equivalence limits for comparison of field strengths/sequences were based on the limits of Bland-Altman analyses of the intraobserver variability. RESULTS: Non-diagnostic quality was found in 10/144 segments, 9/10 were obtained at 7T. Apart for the comparison of forward flow between sequence 1 and 3, the differences in measurements between field strengths/sequences exceeded the range of agreement. Significant differences were found between field strengths/sequences for forward flow (1.5T vs. 3T, 3T vs. 7T, sequence 1 vs. 3, 2 vs. 3 [P < .001]), WSS (1.5T vs. 3T [P < .05], sequence 1 vs. 2, 1 vs. 3, 2 vs. 3 [P < .001]), and peak velocity (1.5T vs. 7T, sequence 1 vs. 3 [P > .001]). All parameters at all field strengths/with all sequences correlated moderately to strongly (r ≥ 0.5). CONCLUSION: Data from all sequences could be acquired and resulting images showed sufficient quality for further analysis. However, the variability of the measurements of peak velocity, flow volumes, and WSS was higher when comparing field strengths/sequences as the equivalence limits defined by the intraobserver assessments.
Authors: Ahmet Demirkiran; Pim van Ooij; Jos J M Westenberg; Mark B M Hofman; Hans C van Assen; Linda J Schoonmade; Usman Asim; Carmen P S Blanken; Aart J Nederveen; Albert C van Rossum; Marco J W Götte Journal: Eur Heart J Cardiovasc Imaging Date: 2022-01-24 Impact factor: 6.875