Artifact meaning medical3/6/2023 ![]() ![]() Most published data on aSAH use the Glasgow Outcome Scale (GOS) and modified Rankin Scale (mRS) that place patients with mild disabilities in a 'Good Recovery' category. Recent advances in aneurysmal subarachnoid hemorrhage (aSAH) management have led to consistent improvement in survival, with case fatality rates decreasing 0.9% every year without a rebound increase in the proportion of survivors with severe disabilities. These findings provide a reference for designing functional and structural neuroimaging studies of recovery in aSAH patients after clip placement. White matter pathways near clip artifacts can be reconstructed and visualized. ConclusionsĪdvanced 3T MR can successfully image brain tissue around implanted titanium aneurysm clips at different spatial ranges depending on sequence type. In both patients, reconstructed white matter pathways of the uncinate fasciculus and inferior fronto-occipital fasciculus were clearly visible within 2 mm of the artifact border. Inter-rater reliability was high (r = 0.9626, p < 0.0001), and reconstruction of white matter connectivity characteristics increased with distance from the artifact border. ResultsĪrtifact volume varied by MR sequence for length (p = 0.007) and volume (p < 0.001) ratios: it was smallest for structural images, larger for DW-MRI acquisitions, and largest on fMRI images. Tractography pathways were reconstructed from DW-MRI at varying distances from the artifacts using deterministic methods. Artifact volumes were quantified by artifact/clip length and artifact/brain volume ratios and analyzed by two-way (scan-by-rater) ANOVAs. Intensity-based planimetric contouring was performed on aligned image volumes to define each artifact. T1- and T2-weighted structural, BOLD-fMRI, and DW-MRI scans were acquired at 3T in two patients with titanium alloy clips in ACOM and left ACA respectively. To characterize the effect of these artifacts on image quality, we sought to: 1) quantify extent of image artifact in SAH patients with implanted aneurysm clips across a range of MR sequences typically used in studies of volumetry, blood oxygen level dependent signal change (BOLD-fMRI), and diffusion-weighted imaging (DW-MRI) and 2) to explore the ability to reconstruct white matter pathways in these patients. The application of advanced 3T MRI imaging techniques to study recovery after subarachnoid hemorrhage (SAH) is complicated by the presence of image artifacts produced by implanted aneurysm clips. ![]()
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