Mariya S Pravdivtseva1, Franziska Gaidzik2, Philipp Berg2, Carson Hoffman3, Leonardo A Rivera-Rivera3, Rafael Medero4, Lindsay Bodart3, Alejandro Roldan-Alzate4, Michael A Speidel3, Kevin M Johnson3, Oliver Wieben3, Olav Jansen5, Jan-Bernd Hövener1, Naomi Larsen5. 1. Section Biomedical Imaging, Molecular Imaging North Competence Center (MOIN CC), Department of Radiology and Neuroradiology, University Medical Center Schleswig-Holstein (UKSH), Kiel University, Kiel, Germany. 2. Laboratory of Fluid Dynamics and Technical Flows, Forschungscampus STIMULATE, University of Magdeburg, Magdeburg, Germany. 3. Department of Medical Physics and Medicine, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA. 4. Department of Mechanical Engineering and Radiology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA. 5. Department of Radiology and Neuroradiology, University Medical Center Schleswig-Holstein, Kiel, Germany.
Abstract
BACKGROUND: Vessel-wall enhancement (VWE) on black-blood MRI (BB MRI) has been proposed as an imaging marker for a higher risk of rupture and associated with wall inflammation. Whether VWE is causally linked to inflammation or rather induced by flow phenomena has been a subject of debate. PURPOSE: To study the effects of slow flow, spatial resolution, and motion-sensitized driven equilibrium (MSDE) preparation on signal intensities in BB MRI of patient-specific aneurysm flow models. STUDY TYPE: Prospective. SUBJECTS/FLOW ANEURYSM MODEL/VIRTUAL VESSELS: Aneurysm flow models based on 3D rotational angiography datasets of three patients with intracranial aneurysms were 3D printed and perfused at two different flow rates, with and without Gd-containing contrast agent. FIELD STRENGTH/SEQUENCE: Variable refocusing flip angle 3D fast-spin echo sequence at 3 T with and without MSDE with three voxel sizes ((0.5 mm)3 , (0.7 mm)3 , and (0.9 mm)3 ); time-resolved with phase-contrast velocity-encoding 3D spoiled gradient echo sequence (4D flow MRI). ASSESSMENT: Three independent observers performed a qualitative visual assessment of flow patterns and signal enhancement. Quantitative analysis included voxel-wise evaluation of signal intensities and magnitude velocity distributions in the aneurysm. STATISTICAL TESTS: Kruskal-Wallis test, potential regressions. RESULTS: A hyperintense signal in the lumen and adjacent to the aneurysm walls on BB MRI was colocalized with slow flow. Signal intensities increased by a factor of 2.56 ± 0.68 (P < 0.01) after administering Gd contrast. After Gd contrast administration, the signal was suppressed most in conjunction with high flows and with MSDE (2.41 ± 2.07 for slow flow without MSDE, and 0.87 ± 0.99 for high flow with MSDE). A clear result was not achieved by modifying the spatial resolution . DATA CONCLUSIONS: Slow-flow phenomena contribute substantially to aneurysm enhancement and vary with MRI parameters. This should be considered in the clinical setting when assessing VWE in patients with an unruptured aneurysm. EVIDENCE LEVEL: 2 TECHNICAL EFFICACY: Stage 2.
BACKGROUND: Vessel-wall enhancement (VWE) on black-blood MRI (BB MRI) has been proposed as an imaging marker for a higher risk of rupture and associated with wall inflammation. Whether VWE is causally linked to inflammation or rather induced by flow phenomena has been a subject of debate. PURPOSE: To study the effects of slow flow, spatial resolution, and motion-sensitized driven equilibrium (MSDE) preparation on signal intensities in BB MRI of patient-specific aneurysm flow models. STUDY TYPE: Prospective. SUBJECTS/FLOW ANEURYSM MODEL/VIRTUAL VESSELS: Aneurysm flow models based on 3D rotational angiography datasets of three patients with intracranial aneurysms were 3D printed and perfused at two different flow rates, with and without Gd-containing contrast agent. FIELD STRENGTH/SEQUENCE: Variable refocusing flip angle 3D fast-spin echo sequence at 3 T with and without MSDE with three voxel sizes ((0.5 mm)3 , (0.7 mm)3 , and (0.9 mm)3 ); time-resolved with phase-contrast velocity-encoding 3D spoiled gradient echo sequence (4D flow MRI). ASSESSMENT: Three independent observers performed a qualitative visual assessment of flow patterns and signal enhancement. Quantitative analysis included voxel-wise evaluation of signal intensities and magnitude velocity distributions in the aneurysm. STATISTICAL TESTS: Kruskal-Wallis test, potential regressions. RESULTS: A hyperintense signal in the lumen and adjacent to the aneurysm walls on BB MRI was colocalized with slow flow. Signal intensities increased by a factor of 2.56 ± 0.68 (P < 0.01) after administering Gd contrast. After Gd contrast administration, the signal was suppressed most in conjunction with high flows and with MSDE (2.41 ± 2.07 for slow flow without MSDE, and 0.87 ± 0.99 for high flow with MSDE). A clear result was not achieved by modifying the spatial resolution . DATA CONCLUSIONS: Slow-flow phenomena contribute substantially to aneurysm enhancement and vary with MRI parameters. This should be considered in the clinical setting when assessing VWE in patients with an unruptured aneurysm. EVIDENCE LEVEL: 2 TECHNICAL EFFICACY: Stage 2.
Authors: Raghav R Mattay; Jose F Saucedo; Vance T Lehman; Jiayu Xiao; Emmanuel C Obusez; Scott B Raymond; Zhaoyang Fan; Jae W Song Journal: Semin Ultrasound CT MR Date: 2021-08-01 Impact factor: 1.641