Published ahead of print on November 1, 2007
doi: 10.3174/ajnr.A0796
Monitoring Serial Change in the Lumen and Outer Wall of Vertebrobasilar Aneurysms
L. Boussela,b,
M. Wintermarkb,
A. Martinb,
B. Dispensac,
R. VanTijena,
J. Leachd,
V. Rayza,
G. Acevedo-Boltona,
M. Lawtone,
R. Higashidab,
W.S. Smithf,
W.L. Youngc and
D. Salonera,b,d,e
a Radiology Service, VA Medical Center, San Francisco, Calif
b Departments of Radiology, University of California San Francisco, San Francisco, Calif
c Anesthesia and Perioperative Care, University of California San Francisco, San Francisco, Calif
d Bioengineering, University of California San Francisco, San Francisco, Calif
e Surgery, University of California San Francisco, San Francisco, Calif
f Neurology, University of California San Francisco, San Francisco, Calif
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Fig 1. MRA study from a patient with a large aneurysm (arrow) of the basilar trunk. Left, Maximum intensity projection in a paracoronal plane. Right, Axial multiplanar reconstruction through the basilar artery (arrow). Also noted are the carotid arteries (arrowheads).
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Fig 2. Steady-state bFFE axial image obtained from the same patient and same plane as on the right of Fig 1. Left, Full FOV image. Right, Magnified image of the aneurysm showing the manual contour used to delineate the outer wall.
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Fig 3. Lumenal and outer wall surfaces for another patient with aneurysmal basilar disease. Left, Surface shaded depiction of the lumen obtained from CE-MRA (blue for the extra-aneurysmal part of lumen and green for intra-aneurysmal part). Right, Surface shaded depiction of the outer wall obtained from bFFE images (red).
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Fig 4. Patient with a fusiform aneurysm of the distal basilar artery. Left, Registration of the lumen of the baseline study (blue) and the most recent study (red). Consistency of threshold across studies is ensured by requiring volume preservation in a reference segment of the carotid artery (black arrow). A detail of this registration by using a mesh display is shown on the right side showing the asymmetrical increase of the lumen volume of the aneurysm.
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Fig 5. The difference between outer wall and inner wall volumes is plotted as a function of outer wall volume. The volume of the aneurysm region that is not circulating increases with increasing aneurysm size.
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Fig 6. Changes of the inner and outer walls of aneurysms over time. Left, Plot of change in lumen shows that the lumenal wall of the aneurysm can either increase or decrease. The substantial decrease in lumen size for patient 3 is related to a partial thrombosis of the lumen between the 2 first time points. Right, Plot of changes in outer wall over time shows that changes are highly variable between individuals. Outer wall volumes either remain essentially unchanged (±5%) or increase over time.
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Fig 7. Plot of the ratio of lumen-to-outer-wall volume over time. Relative evolution of the 2 components (lumen and thrombus) of the aneurysms is variable from 1 patient to another.
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Fig 8. Bland-Altman plot representation of outer wall volume measured from bFFE and T1-weighted TSE sequence. Solid line shows the mean difference and dotted lines the 95% confidence interval of the mean.
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