Meeting Banner
Abstract #4250

Retrospective Distortion Correction Using the ADNI Phantom to Salvage Unusable Exams

Bogdan Dzyubak1, Jeffrey L. Gunter1, Edward Brian Welch2, Ron J. Killiany3, Clifford R. Jack1, Matt A. Bernstein1

1Radiology, Mayo Clinic, Rochester, MN, United States; 2Philips Healthcare, Highland Heights, OH, United States; 3Boston University School of Medicine, Boston, MA, United States

During the Alzheimers Disease Neuroimaging Initiative (ADNI) multicenter study, a laser alignment light was mis-calibrated on one scanner, leading to a displacement error in the isocenter location used during image reconstruction. Consequently, the standard gradient distortion correction was inaccurate and the resulting data were unusable for longitudinally tracking brain changes. Off-line processing was used to remove the aberrant distortion correction from ADNI phantom data, then those images were shifted by a variable displacement, and finally the images were re-corrected for gradient distortion. The actual displacement error was determined by this method and the subject data could be re-corrected and salvaged.