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Quantifying metal‐induced susceptibility artifacts of the instrumented spine at 1.5T using fast‐spin echo and 3D‐multispectral MRI
Author(s) -
Kaushik S. Sivaram,
Karr Robin,
Runquist Matthew,
Marszalkowski Cathy,
Sharma Abhishiek,
Rand Scott D.,
Maiman Dennis,
Koch Kevin M.
Publication year - 2017
Publication title -
journal of magnetic resonance imaging
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.563
H-Index - 160
eISSN - 1522-2586
pISSN - 1053-1807
DOI - 10.1002/jmri.25321
Subject(s) - multispectral image , fast spin echo , spine (molecular biology) , nuclear magnetic resonance , medicine , magnetic resonance imaging , radiology , physics , geology , remote sensing , biology , microbiology and biotechnology
Purpose To evaluate magnetic resonance imaging (MRI) artifacts near metallic spinal instrumentation using both conventional metal artifact reduction sequences (MARS) and 3D multispectral imaging sequences (3D‐MSI). Materials and Methods Both MARS and 3D‐MSI images were acquired in 10 subjects with titanium spinal hardware on a 1.5T GE 450W scanner. Clinical computed tomography (CT) images were used to measure the volume of the implant using seed‐based region growing. Using 30–40 landmarks, the MARS and 3D‐MSI images were coregistered to the CT images. Three independent users manually segmented the artifact volume from both MR sequences. For five L‐spine subjects, one user independently segmented the nerve root in both MARS and 3D‐MSI images. Results For all 10 subjects, the measured artifact volume for the 3D‐MSI images closely matched that of the CT implant volume (absolute error: 4.3 ± 2.0 cm 3 ). The MARS artifact volume was ∼8‐fold higher than that of the 3D‐MSI images (30.7 ± 20.2, P = 0.002). The average nerve root volume for the MARS images was 24 ± 7.3% lower than the 3D‐MSI images ( P = 0.06). Conclusion Compared to 3D‐MSI images, the higher‐resolution MARS images may help study features farther away from the implant surface. However, the MARS images retained substantial artifacts in the slice‐dimension that result in a larger artifact volume. These artifacts have the potential to obscure physiologically relevant features, and can be mitigated with 3D‐MSI sequences. Hence, MR study protocols may benefit with the inclusion both MARS and 3D‐MSI sequences to accurately study pathology near the spine. Level of Evidence: 2 J. Magn. Reson. Imaging 2017;45:51–58.