Jang Gyu Cha MD, Presenter: Nothing to Disclose

Wook Jin, Abstract Co-Author: Nothing to Disclose

Moonjung Hwang, Abstract Co-Author: Research support, General Electric Company

Min Hee Lee MD, Abstract Co-Author: Nothing to Disclose

Jai Soung Park, Abstract Co-Author: Nothing to Disclose

Seong Jin Park MD, PhD, Abstract Co-Author: Nothing to Disclose

To prospectively compare the effectiveness of iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL) T2 and contrast enhanced T1-weighted imaging(CE-T1WI) with a conventional MR imaging protocol for minimizing metallic artifact in a phantom and postoperative spines with metallic hardware.

All imagings were performed on a 1.5T MR system with a dedicated spinal coil. Fat saturated(FS) coronal T1 and T2 -weighted MR images with and without IDEAL were obtained through seven metal phantoms (titanium alloy pedicle screw) immersed in an oil bath containing cylindrical tubes filled with 1/250 diluted gadolinium contrast. MR imaging of spine was performed with axial FS-T2 and CE-T1 WI with and without IDEAL technique in 22 lumbar levels of 19 patients ( M:F=8:11; age range: 36-77 years, mean: 59.3 years ). Qualitative study was made by two musculoskeletal radiologists in terms of visualization of paravertebral muscle and spinal canal region, uniformity of fat saturation and noise. The paired images were rated on a five-point scale. For quantitative study by using phantoms, short and long-axis length of metallic artifact were measured by using profile of signal intensity. Statistical analysis was performed by using paired T-test for comparison of MR images with and without IDEAL. Interobserver agreement was assessed with the weighted κ statistic.

In the phantom, metallic artifact size was markedly decreased on the IDEAL CE-T1 and T2 WI. (P < .001). In the clinical study, IDEAL CE-T1 and T2 WI resulted in significantly improved visualization of the spinal canal (P < .001), spinal muscles(P < .05), uniformity fat saturation (P < .001)and noise (P < .05) by two reviewers. Interobserver agreements were fair to excellent.

IDEAL CE-T1 and T2 WI effectively reduces the degree of tissue-obscuring artifact produced by spinal fixation hardware and improves image quality compared with the conventional sequences.

The reduction of image artifact achieved with IDEAL technique enhances visualization of the spine and surrounding structures in postoperative spine, which subsequently may affect patient management.

Cha, J, Jin, W, Hwang, M, Lee, M, Park, J, Park, S, Usefulness of  IDEAL Contrast-enhanced T1- and T2-weighted Imaging in Reducing Metallic Artifact in Postoperative Spines: A Phantom and Clinical Study.  Radiological Society of North America 2010 Scientific Assembly and Annual Meeting, November 28 - December 3, 2010 ,Chicago IL. http://archive.rsna.org/2010/9000005.html