Silent MRA of intracranial arteries: follow-up of aneurysms treated with coils

Intracranial aneurysms are currently treated with endovascular techniques like
coiling and stenting. After treatment, imaging is required to demonstrate that
the aneurysm has been excluded from the circulation. Current imaging strategies
include TOF MRA as the first modality for evaluation. Spin dephasing and
saturation constitute major limitations of 3D TOF-MRA; these might influence
the detection and evaluation of residual aneurysmal pouches. Contrast-enhanced
MRA (CE-MRA) has been used to increase signal intensity in residual pouches;
however, venous enhancement often degrades image quality

Recently a new sequence is developed. Silent MR techniques based on zero TE
technology have the advantage of reducing acoustic noise during acquisition,
which improves patient comfort and cooperation. The question still to be
answered is whether image quality and accuracy is affected by this new
approach. The zero TE approach in combination with endpoints following a spiral
path might also provide additional features for optimization of image quality.
For evaluation of intracranial arteries and of atherosclerotic disease in the
carotid bifurcation, Zero TE MRI and MRA might reduce motion and flow artifacts
which normally hamper accurate evaluation.

TOF MRA is dependent on flow, which may mean that recanalisation of a coiled
aneurysm is not visualised with this protocol. Spin dephasing due to circular
flow in aneurysmal remnants is absent in the zero TE approach. CEMRA requires
the injection of contrast agents. Both sequences produce acoustic noise. Silent
MRA with ASL preparation might replace TOF MRA and CEMRA in the follow-up of
patients with coiled aneurysms.

The proposed studies will demonstrate what the additional value is of the
Silent MRI in the visualization in patients treated with coils. The studies
will make clear whether the next phase, clinical use of the sequences, is
warranted.

Test the optimized MRI sequences/technology against commercially-available,
clinical MRI
sequences in terms of image quality, signal-to-noise ratio (SNR),
contrast-to-noise ratio
(CNR), speed, and accuracy/reproducibility of extracted quantitative parameters

Observational diagnostic study.

1. Nature and extent of the burden and risks associated with participation,
benefit and group relatedness: Burden: MRI extension for maximum 40 minutes and
exposure to acoustic noise.