Improved MR imaging for patients with metallic implants

Pediatric oncology patients with large metallic prostheses were imaged with one of two MR imaging techniques: 1) the "tilted view-angle" technique, 2) or a higher readout bandwidth technique. The tilted view-angle method uses an additional gradient in the slice selection direction during readout. Th e high bandwidth technique increases the readout bandwidth and shortens the echo time (TE). High bandwidth and short echo times were implemented in bo th T-1-weighted (T1W) turbo spin echo and turbo short tau inversion recover y (STIR) sequences. Both imaging techniques reduced the size of metal-induc ed image artifacts. The tilted view-angle method reduced the artifact to a greater degree but had inherent shortcomings. The reformatted images were b lurred and shifted. The area of interest was often moved outside of the fie ld of view, unless parameters were adjusted on the basis of a pre-scan calc ulation. The high readout bandwidth, short echo technique required no speci al preparation and reduced metal artifacts without image blurring. The comb ination of high-bandwidth, shorter echo turbo STIR and T1W turbo spin echo sequences with subtraction of pre- from post-contrast images allowed effect ive fat suppression without local field inhomogeneity affects. This greatly improved our ability to evaluate suspected disease near metallic implants in pediatric cancer patients. (C) 2000 Elsevier Science Inc. All rights res erved.