Artefact on MRA following aneurysm clipping: an in vitro study and prospective comparison with conventional angiography.
Using both an experimental model and clinical cases, we looked at the artefact produced by Aesculap titanium-alloy aneurysm clips on MRA. Experimentally, the volume affected by artefact was 50 % less when the clip was imaged lying parallel to the main ferromagnetic field than when lying perpendicular to it. Clinically, MRA was prospectively compared with digital subtraction angiography (DSA) in nine patients who had undergone aneurysm clipping. One patient with a non-diagnostic MRA due to movement artefact was excluded. In all other cases there was an area of signal loss surrounding the clips, obscuring the immediately adjacent vessel segments. There was good demonstration of the adjacent bifurcations in five cases and the contralateral circulation was seen well in all patients. In three cases in which the adjacent bifurcations were not seen, considerable vasospasm was suggested by MRA and confirmed with DSA. In one patient an unclipped contralateral ophthalmic artery aneurysm was identified using both modalities. In this series there were no adverse events relating to clips in either static or time-varying magnetic fields.
Grieve
J P
JP
University Department of Neurosurgery, Institute of Neurology, Queen Square, London WC1N 3BG, UK.
Stacey
R
R
Moore
E
E
Kitchen
N D
ND
Jäger
H R
HR
D000328:Adult; D000368:Aged; D015901:Angiography, Digital Subtraction; D016477:Artifacts; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D002532:Intracranial Aneurysm / Q000175:diagnosis / Q000601:surgery*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D019047:Phantoms, Imaging; D011183:Postoperative Complications / Q000175:diagnosis*; D011446:Prospective Studies; D013345:Subarachnoid Hemorrhage / Q000175:diagnosis / Q000601:surgery; D013525:Surgical Instruments; D014025:Titanium
D014025:Titanium