Time-of-Flight MR Angiography Targeted to Coiled Intracranial Aneurysms Is More Sensitive to Residual Flow than Is Digital Subtraction Angiography
Naoaki Yamadaa,
Katsuhiko Hayashib,
Kenichi Muraob,
Masahiro Higashia and
Koji Iiharab
a Department of Radiology and Nuclear Medicine, National Cardiovascular Center, Osaka, Japan
b Department of Neurosurgery, National Cardiovascular Center, Osaka, Japan
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FIG 1. A thin-neck remnant invisible with initial DSA.
A, Oblique DSA image at the end of coil placement shows no flow in the aneurysm at left internal carotid artery (complete obliteration).
B and C, MRA images 3 days after coil placement. Closely targeted MIP to the aneurysm in a projection similar to that of the DSA (B) and MRA source image (C) show a neck remnant that is thin and relatively deep (arrows).
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FIG 2. A thick-neck remnant visualized with follow-up DSA images obtained 8 months after initial images.
A, DSA image shows a neck remnant.
B and C, Closely targeted MIP (B) and source image (C) of MRA show a neck remnant (arrows) that is thick and larger than that visualized with DSA.
D, Black-blood image obtained by using 3D turbo spin-echo shows no signal intensity in the aneurysm (arrow) and arteries.
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FIG 3. Signal intensity void in parent artery and susceptibility artifact immediately after coil placement.
A, DSA shows an aneurysm at basilar artery–superior cerebellar artery bifurcation at the end of coil placement. Neck remnant (arrowhead) and protrusion of a coil into the basilar artery (arrow) are observed.
B, Targeted MIP of MRA image obtained 3 days after coil placement shows neck remnant more clearly than does DSA image (arrowhead). Signal intensity loss in the basilar artery (arrow) is due to coil protrusion. Signal intensity loss in left posterior cerebral artery (asterisk) is due to susceptibility artifact of the clip in another aneurysm at the left internal carotid–posterior communicating artery bifurcation.
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