Assessing MRI susceptibility artefact through an indicator of image distortion

Susceptibility artefacts in magnetic resonance imaging (MRI) caused by medical devices can result in a severe degradation of the MR image quality. The quantification of susceptibility artefacts is regulated by the ASTM standard which defines a manual method to assess the size of an artefact. This means that the estimated artefact size can be user dependent. To cope with this problem, we propose an algorithm to automatically quantify the size of such susceptibility artefacts. The algorithm is based on the analysis of a 3D surface generated from the 2D MR images. The results obtained by the automatic algorithm were compared to the manual measurements performed by study participants. The results show that the automatic and manual measurements follow the same trend. The clear advantage of the automated algorithm is the absence of the inter- and intra-observer variability. In addition, the algorithm also detects the slice containing the largest artefact which was not the case for the manual measurements.

MR susceptibility artefact associated with the use of Barricade coils for treatment of intracranial aneurysms

Magnetic resonance angiography (MRA) is commonly used to follow up patients after endovascular treatment for intracranial aneurysms. Magnetic resonance artefacts from coil constructs may impair image quality and jeopardise the evaluation of the effectiveness of treatment and review of adjacent vasculature. We present here a technical note on the usage of Barricade coils recently introduced at our institution. The MRA artefacts associated with these coils may make it impossible to ascertain aneurysm closure and anatomy. Hence these patients would need to be recalled for digital subtraction angiograms for a complete neuroradiological follow-up.