Background: The application of advanced 3T MRI imaging techniques to study recovery after subarachnoid\r\nhemorrhage (SAH) is complicated by the presence of image artifacts produced by implanted aneurysm clips. To\r\ncharacterize the effect of these artifacts on image quality, we sought to: 1) quantify extent of image artifact in SAH\r\npatients with implanted aneurysm clips across a range of MR sequences typically used in studies of volumetry,\r\nblood oxygen level dependent signal change (BOLD-fMRI), and diffusion-weighted imaging (DW-MRI) and 2) to\r\nexplore the ability to reconstruct white matter pathways in these patients.\r\nMethods: T1- and T2-weighted structural, BOLD-fMRI, and DW-MRI scans were acquired at 3T in two patients with\r\ntitanium alloy clips in ACOM and left ACA respectively. Intensity-based planimetric contouring was performed on\r\naligned image volumes to define each artifact. Artifact volumes were quantified by artifact/clip length and artifact/\r\nbrain volume ratios and analyzed by two-way (scan-by-rater) ANOVAs. Tractography pathways were reconstructed\r\nfrom DW-MRI at varying distances from the artifacts using deterministic methods.\r\nResults: Artifact volume varied by MR sequence for length (p = 0.007) and volume (p < 0.001) ratios: it was\r\nsmallest for structural images, larger for DW-MRI acquisitions, and largest on fMRI images. Inter-rater reliability was\r\nhigh (r = 0.9626, p < 0.0001), and reconstruction of white matter connectivity characteristics increased with\r\ndistance from the artifact border. In both patients, reconstructed white matter pathways of the uncinate fasciculus\r\nand inferior fronto-occipital fasciculus were clearly visible within 2 mm of the artifact border.\r\nConclusions: Advanced 3T MR can successfully image brain tissue around implanted titanium aneurysm clips at\r\ndifferent spatial ranges depending on sequence type. White matter pathways near clip artifacts can be\r\nreconstructed and visualized. These findings provide a reference for designing functional and structural\r\nneuroimaging studies of recovery in aSAH patients after clip placement.
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