Artikel
Magnetic resonance imaging of thrombosed unruptured intracranial aneurysms at 7 Tesla
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Autoren
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Toshinori Matsushige
- Klinik für Neurochirurgie, Universitätsklinik Essen, Germany; Department of Neurosurgery, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan; Erwin L. Hahn Institute for Magnetic Resonance Imaging, Universität Duisburg-Essen, Germany
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Philipp Dammann
- Klinik für Neurochirurgie, Universitätsklinik Essen, Germany; Erwin L. Hahn Institute for Magnetic Resonance Imaging, Universität Duisburg-Essen, Germany
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Harald H. Quick
- Erwin L. Hahn Institute for Magnetic Resonance Imaging, Universität Duisburg-Essen, Germany; High Field and Hybrid MR Imaging, Universität Duisburg-Essen, Germany
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Michael Forsting
- Institut für Diagnostische und Interventionelle Radiologie und Neuroradiologie, Universitätsklinik Essen, Germany
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Ulrich Sure
- Klinik für Neurochirurgie, Universitätsklinik Essen, Germany
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Karsten H. Wrede
- Klinik für Neurochirurgie, Universitätsklinik Essen, Germany; Erwin L. Hahn Institute for Magnetic Resonance Imaging, Universität Duisburg-Essen, Germany
| Veröffentlicht: | 8. Juni 2016 |
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Gliederung
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Objective: The pathophysiology of formation, growth and rupture of thrombosed intracranial aneurysms supposedly differs from non-thrombosed aneurysms. This in-vivo 7 Tesla MRI study visualizes thrombosed unruptured intracranial aneurysms (UIA) with special focus on the aneurysm wall microstructure.
Method: Twelve patients with 13 thrombosed UIAs were prospectively evaluated using an ultra-high-field 7 Tesla whole-body MRI system. Acquired MRI sequences included: time-of-flight (TOF) magnetic resonance angiography (MRA), magnetization prepared rapid gradient echo (MPRAGE) and susceptibility weighted imaging (SWI). Gadolinium enhancement was used in 8 patients with 9 aneurysms. Three aneurysms were available for histopathological examination. Two experienced raters assessed the aneurysm and wall microstructures and perifocal edema in consensus reading.
Results: The study group comprised 7 male and 5 female patients with an average age of 58.5 (standard error of the mean (SEM) 3.0, range 44 - 80). Aneurysm locations included: 4 at internal carotid artery, 5 at middle cerebral artery, 2 at distal anterior cerebral artery, 1 at posterior cerebral artery and 1 at basilar artery. The mean diameter of aneurysms and parent artery were 24.9 mm (SEM 2.1, range 11.1 - 37.9 mm). Thrombosed aneurysm wall had low signal intensity in all acquired sequences. Contrast ratios between aneurysm wall and surrounding brain parenchyma in TOF, MPRAGE, and SWI were 0.46, 0.20 and 0.83, respectively (p < 0.05). All thrombosed aneurysms showed a triple-layered wall microstructure furthest away from the aneurysm base. Wall enhancement was present in all aneurysms (n = 9) after intravenous Gadolinium contrast media administration. Five of these showed a double ring wall enhancement (outer and inner layer) and 4 were depicted with a single ring enhancement (only inner layer). Aneurysms with double ring enhancement had additional perifocal edema formation. Three histopathological studies suggested development of vasa vasorum in adventitia corresponding to outer aneurysm wall enhancement. Contrast enhancement of inner aneurysm wall might be explained by neovascularization in a layer interfacing between aneurysm wall and intraluminal thrombus.
Conclusions: High-resolution in-vivo 7 Tesla MRI can visualize thrombosed UIAs in excellent image quality and depict the triple-layered wall microstructure. Two different wall enhancement patterns of thrombosed UIAs were identified.
