AbstractOBJECTIVE:To test the spatial accuracy of coordinates generated from magnetic resonance imaging (MRI) scans, using the Brown-Roberts-Wells head frame and localizer system (Radionics, Inc., Burlington, MA).METHODS:An anthropomorphic head phantom, consisting of a two-dimensional lattice of acrylic spheres (4-mm diameter) spaced 10 mm apart and embedded in a brain tissue-mimicking gelatin-agar gel, was constructed. The intersphere distances for the target lattice positions in MRI and computed tomographic scan sets were compared. The data sets were fused, and differences in fiducial marker and intraphantom target positions were measured.RESULTS:Intersphere distances were identical for the MRI and computed tomographic scan sets (10 ± 0.1 mm). Differences in fiducial marker positions [maximal lateral difference, 0.97 mm; mean absolute lateral difference, 0.69 ± 0.22 mm; maximal anteroposterior (AP) difference, 1.99 mm; mean absolute AP difference, 1.29 ± 0.67 mm] were correlated with differences in intraphantom target positions (maximal lateral difference, 0.83 mm; mean absolute lateral difference, 0.28 ± 0.24 mm; maximal AP difference, -1.97 mm; mean absolute AP difference, 1.63 ± 25 mm; maximal vertical difference, -0.73 mm; mean absolute vertical difference, 0.34 ± 0.21 mm). This suggested that improper fiducial rod identification and the subsequent transformation to stereotactic coordinate space were the greatest sources of spatial uncertainty.CONCLUSION:With computed tomographic data as the standard, these differences resulted in maximal and minimal composite uncertainties of 2.06 and 1.17 mm, respectively. The measured uncertainties exceed recommended standards for radiosurgery but allow the possible use of MRI-based stereotactic treatment planning for certain intracranial lesions, if the errors are corrected using appropriate software. Clinicians must recognize that error magnitudes vary for different systems, and they should perform systematic, scheduled, institutional error analyses as part of their ongoing quality assurance processes. This phantom provides one tool for measuring suchvariances.
Neurosurgery – Oxford University Press
Published: Dec 1, 1999
It’s your single place to instantly
discover and read the research
that matters to you.
Enjoy affordable access to
over 12 million articles from more than
10,000 peer-reviewed journals.
All for just $49/month
Read as many articles as you need. Full articles with original layout, charts and figures. Read online, from anywhere.
Keep up with your field with Personalized Recommendations and Follow Journals to get automatic updates.
It’s easy to organize your research with our built-in tools.
Read from thousands of the leading scholarly journals from SpringerNature, Elsevier, Wiley-Blackwell, Oxford University Press and more.
All the latest content is available, no embargo periods.
“Hi guys, I cannot tell you how much I love this resource. Incredible. I really believe you've hit the nail on the head with this site in regards to solving the research-purchase issue.”Daniel C.
“Whoa! It’s like Spotify but for academic articles.”@Phil_Robichaud
“I must say, @deepdyve is a fabulous solution to the independent researcher's problem of #access to #information.”@deepthiw
“My last article couldn't be possible without the platform @deepdyve that makes journal papers cheaper.”@JoseServera