Influence of Spatial Resolution and Compressed SENSE Acceleration Factor on Flow Quantification with 4D Flow MRI at 3 Tesla
Mariya S. Pravdivtseva,
Franziska Gaidzik,
Philipp Berg,
Patricia Ulloa,
Naomi Larsen,
Olav Jansen,
Jan-Bernd Hövener,
Mona Salehi Ravesh
Affiliations
Mariya S. Pravdivtseva
Department of Radiology and Neuroradiology, University Medical Center Schleswig-Holstein (UKSH), Section Biomedical Imaging, Molecular Imaging North Competence Center (MOIN CC), Kiel University, 24105 Kiel, Germany
Franziska Gaidzik
Department of Fluid Dynamics and Technical Flows, Research Campus STIMULATE, Magdeburg University, 39106 Magdeburg, Germany
Philipp Berg
Department of Fluid Dynamics and Technical Flows, Research Campus STIMULATE, Magdeburg University, 39106 Magdeburg, Germany
Patricia Ulloa
Department of Radiology and Neuroradiology, University Medical Center Schleswig-Holstein (UKSH), Section Biomedical Imaging, Molecular Imaging North Competence Center (MOIN CC), Kiel University, 24105 Kiel, Germany
Naomi Larsen
Department of Radiology and Neuroradiology, University Medical Center Schleswig-Holstein (UKSH), Kiel University, 24105 Kiel, Germany
Olav Jansen
Department of Radiology and Neuroradiology, University Medical Center Schleswig-Holstein (UKSH), Kiel University, 24105 Kiel, Germany
Jan-Bernd Hövener
Department of Radiology and Neuroradiology, University Medical Center Schleswig-Holstein (UKSH), Section Biomedical Imaging, Molecular Imaging North Competence Center (MOIN CC), Kiel University, 24105 Kiel, Germany
Mona Salehi Ravesh
Department of Radiology and Neuroradiology, University Medical Center Schleswig-Holstein (UKSH), Section Biomedical Imaging, Molecular Imaging North Competence Center (MOIN CC), Kiel University, 24105 Kiel, Germany
Four-dimensional (4D) flow MRI allows quantifying flow in blood vessels–non invasively and in vivo. The clinical use of 4D flow MRI in small vessels, however, is hampered by long examination times and limited spatial resolution. Compressed SENSE (CS-SENSE) is a technique that can accelerate 4D flow dramatically. Here, we investigated the effect of spatial resolution and CS acceleration on flow measurements by using 4D flow MRI in small vessels in vitro at 3 T. We compared the flow in silicon tubes (inner diameters of 2, 3, 4, and 5 mm) measured with 4D flow MRI, accelerated with four CS factors (CS = 2.5, 4.5, 6.5, and 13) and three voxel sizes (0.5, 1, and 1.5 mm3) to 2D flow MRI and a flow sensor. Additionally, the velocity field in an aneurysm model acquired with 4D flow MRI was compared to the one simulated with computational fluid dynamics (CFD). A strong correlation was observed between flow sensor, 2D flow MRI, and 4D flow MRI (rho > 0.94). The use of fewer than seven voxels per vessel diameter (nROI) resulted in an overestimation of flow in more than 5% of flow measured with 2D flow MRI. A negative correlation (rho = −0.81) between flow error and nROI were found for CS = 2.5 and 4.5. No statistically significant impact of CS factor on differences in flow rates was observed. However, a trend of increased flow error with increased CS factor was observed. In an aneurysm model, the peak velocity and stagnation zone were detected by CFD and all 4D flow MRI variants. The velocity difference error in the aneurysm sac did not exceed 11% for CS = 4.5 in comparison to CS = 2.5 for all spatial resolutions. Therefore, CS factors from 2.5–4.5 can appear suitable to improve spatial or temporal resolution for accurate quantification of flow rate and velocity. We encourage reporting the number of voxels per vessel diameter to standardize 4D flow MRI protocols.
