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Updated: May 26, 2026
The Helsinki Rat Microsurgical Sidewall Aneurysm Model
Published on: October 12, 2014
Temporal evolution of susceptibility artifacts from coiled aneurysms on MR angiography: an in vivo canine study
G Spilberg1, S L Carniato, R M King
1Department of Radiology, New England Center for Stroke Research, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA.
Background And Purpose:
Intracranial aneurysms treated by coiling have a risk for recurrence, requiring surveillance imaging. MRA has emerged as an attractive technique for postcoiling aneurysm imaging. Previous research has evaluated MR imaging artifacts of the coil mass in vitro. Our aim in this study was to evaluate MR imaging artifacts of coiled aneurysms in vivo with time.
Materials And Methods:
Four sidewall aneurysms were created in each of 4 dogs. Aneurysms were embolized receiving only 1 type of coils. After embolization, the animals were transferred to MR imaging, which included axial 3D TOF MRA (TEs, 3.5, 5, and 6.9 ms), phase-contrast MRA, and coronal CE-MRA. MR imaging studies were repeated at 1, 4, 6, 8, 14, and 28 weeks. We calculated an OEF: OEF = V(A)/V(CM), where the numerator represents the volume of the MR imaging artifacts and the denominator is the true volume of the coil mass measured by 3D RA.
Results:
OEFs were largest immediately after embolization and showed a gradual decay until approximately 4 weeks, when there was stabilization of the size of the artifacts. By 4 weeks, there was mild coil compaction (average coil mass volume decrease of 7.8%); however, the OEFs decreased by 25% after 4 weeks (P < .001).
Conclusions:
MR imaging susceptibility artifacts change with time, being maximal in the postembolization setting and decaying until 4 weeks. The clinical implications of this study are that baseline MRA for comparison with future imaging should be acquired at a minimum of 1 week after the procedure.
Insights
MR imaging artifacts from aneurysm coiling decrease over time, stabilizing by 4 weeks. Baseline MRA for surveillance should be obtained at least 1 week post-procedure to account for these changes.
Area of Science:
- Neurosurgery
- Radiology
- Biomedical Engineering
Background:
- Intracranial aneurysms treated with coiling require surveillance imaging due to recurrence risk.
- Magnetic Resonance Angiography (MRA) is a key imaging technique for post-coiling assessment.
- In vitro studies have evaluated MR imaging artifacts from coil masses, but in vivo data is limited.
Purpose of the Study:
- To evaluate the temporal changes of MR imaging artifacts from coiled intracranial aneurysms in vivo.
- To determine the optimal timing for baseline MRA acquisition after aneurysm coiling.
Main Methods:
- Four dogs underwent embolization of created sidewall aneurysms using a single type of coil.
- Post-embolization MR imaging included 3D Time-of-Flight MRA, phase-contrast MRA, and contrast-enhanced MRA.
- Imaging studies were repeated at intervals from 1 to 28 weeks, with artifact volume (V(A)) and coil mass volume (V(CM)) calculated to determine the artifact over extent (OEF).
Main Results:
- Artifact over extent (OEF) was maximal immediately after embolization and gradually decreased, stabilizing by 4 weeks.
- Coil mass volume decreased by an average of 7.8% by 4 weeks.
- OEF significantly decreased by 25% after 4 weeks (P < .001).
Conclusions:
- MR imaging susceptibility artifacts associated with aneurysm coiling diminish over time, reaching a stable state by 4 weeks.
- The largest artifacts occur in the immediate post-embolization period.
- Baseline MRA for comparison with future surveillance imaging should be performed at a minimum of 1 week after the coiling procedure.
