Wall enhancement of intracranial saccular and fusiform aneurysms may differ in intensity and extension: a pilot study using 7-T high-resolution black-blood MRI
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To evaluate and compare wall enhancement patterns in saccular and fusiform intracranial aneurysms using high-resolution black-blood MRI at 7 T.
Thirty-one patients with 32 unruptured intracranial aneurysms (21 saccular and 11 fusiform) underwent 7-T black-blood MRI. Aneurysm wall enhancement (AWE) was categorized as follows: no wall enhancement (NWE), focal wall enhancement (FWE), and uniform wall enhancement (UWE). The degree of enhancement was scored as follows: 0 (no enhancement), 1 (signal intensity (SI) of the aneurysm wall less than that of the pituitary infundibulum), and 2 (equal to that of the pituitary infundibulum). The chi-squared test was used to compare the AWE pattern and degree between saccular and fusiform aneurysms.
In saccular aneurysms, 12/21 (57%) enhanced. Of these, 9 showed FWE (5 grade 1 and 4 grade 2), and 3 showed UWE (2 grade 1 and 1 grade 2). In fusiform aneurysms, 11/11 (100%) enhanced. Of these, 1 showed FWE and 10 showed UWE. All fusiform aneurysms had grade-2 enhancement. Fusiform aneurysms had more extensive and higher SI AWE than saccular aneurysms (p < 0.01) despite having a similar size (6.9 ± 3.0 mm vs. 8.0 ± 2.9, p = 0.23). For saccular aneurysm, larger aneurysm size was correlated with higher degree of enhancement with Pearson’s r = 0.64 (p = 0.002).
Intracranial fusiform aneurysms had enhancement of higher SI and that covered a more extensive area than saccular aneurysms, which might indicate differences in vessel wall pathology.
• Intracranial aneurysm wall enhancement can be reliably characterized by 7-T black-blood MRI.
• AWE in intracranial fusiform aneurysms presents over a larger surface area and with greater signal intensity as compared with that in saccular aneurysms, which might indicate differences in pathology.
• Stronger signal intensity of AWE correlates with the aneurysm size in saccular aneurysms.
KeywordsMagnetic resonance imaging Gadolinium Saccular aneurysm Fusiform aneurysm Pathology
Aneurysm wall enhancement
Delay alternating with nutation for tailored excitation
Focal wall enhancement
Improved motion-sensitized driven-equilibrium
No wall enhancement
Fast spin echo with variable flip angle trains
Uniform wall enhancement
We sincerely thank all the patients and health care workers who participated in this study.
The authors disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: “National Key R&D Program of China,” grant no. Z161100002616002; “Scientific and Technological Projects of Science and Technology Commission of Beijing,” grant no. 2017YFB1304400.
Compliance with ethical standards
The scientific guarantor of this publication is Youxiang Li.
Conflict of interest
The authors of this manuscript declare no relationships with any companies whose products or services may be related to the subject matter of the article.
Statistics and biometry
One of the authors has significant statistical expertise.
Written informed consent was obtained from all subjects (patients) in this study.
Institutional Review Board approval was obtained.
• Performed at one institution
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