Vascular Wall Imaging of Unruptured Cerebral Aneurysms with a Hybrid of Opposite-Contrast MR Angiography.
OBJECTIVE
Inflammation and degeneration of the intracranial saccular aneurysm wall play a major role in aneurysm formation, development and subsequent rupture. The aim of this study was to characterize the walls of unruptured intracranial aneurysms by using a hybrid of opposite-contrast MRA at 3T.


METHODS
Fourteen consecutive patients with 17 unruptured intracranial aneurysms who initially underwent clipping surgery were prospectively evaluated. All aneurysms were scanned preoperatively by using a hybrid of opposite-contrast MRA in 3T high-resolution MR imaging. We classified intraoperative findings of atherosclerotic plaques in the aneurysms into 3 grades: grade A (major plaques), grade B (minor plaques), and grade C (no plaques). The contrast ratio of the high-intensity area was also measured relative to the background low-intensity area inside the carotid artery.


RESULTS
Findings from preoperative plaque imaging of the aneurysm corresponded to the intraoperative findings in 15 of 16 aneurysms (excluding 1 that was impossible to visualize in its entirety due to anatomic reasons). Overall sensitivity and specificity of the hybrid of opposite-contrast MRA were 88.9% and 100%, respectively. During the operation, 4 aneurysms were classified as grade A; 5, as grade B; and 7, as grade C. The means of the contrast ratio for grades A, B, and C were 0.72 ± 0.03, 0.34 ± 0.30, and -0.02 ± 0.09, respectively.


CONCLUSIONS
The hybrid of opposite-contrast MRA can detect visible atherosclerotic plaques in the unruptured aneurysm wall, and the contrast ratio in intracranial aneurysms correlated with their presence and extent. A study including a larger series is needed to validate the diagnostic potential of this imaging technique.
From the Department of Neurosurgery (T.M., T.O., K.S., N.I., K.K.), Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan Department of Neurosurgery (T.M.), University Hospital Essen, Essen, Germany teruteru728@hiroshima-u.ac.jp.
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T
Matsushige
Department of Diagnostic Radiology (Y.A., K.A.), Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan.
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Y
Akiyama
From the Department of Neurosurgery (T.M., T.O., K.S., N.I., K.K.), Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan.
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Okazaki
From the Department of Neurosurgery (T.M., T.O., K.S., N.I., K.K.), Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan.
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Shinagawa
From the Department of Neurosurgery (T.M., T.O., K.S., N.I., K.K.), Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan.
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Ichinose
Department of Diagnostic Radiology (Y.A., K.A.), Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan.
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Awai
From the Department of Neurosurgery (T.M., T.O., K.S., N.I., K.K.), Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan.
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Kurisu
D000328:Adult; D000368:Aged; D017536:Carotid Artery, Common / Q000000981:diagnostic imaging; D002533:Cerebral Angiography / Q000379:methods*; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D002532:Intracranial Aneurysm / Q000000981:diagnostic imaging*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D058226:Plaque, Atherosclerotic / Q000000981:diagnostic imaging