PT  - JOURNAL ARTICLE
AU  - S.-C. Hung
AU  - C.-C. Wu
AU  - C.-J. Lin
AU  - W.-Y. Guo
AU  - C.-B. Luo
AU  - F.-C. Chang
AU  - C.-Y. Chang
TI  - Artifact Reduction of Different Metallic Implants in Flat Detector C-Arm CT
AID  - 10.3174/ajnr.A3851
DP  - 2014 Jan 23
TA  - American Journal of Neuroradiology
4099  - http://www.ajnr.org/content/early/2014/01/23/ajnr.A3851.short
4100  - http://www.ajnr.org/content/early/2014/01/23/ajnr.A3851.full
AB  - BACKGROUND AND PURPOSE: Flat detector CT has been increasingly used as a follow-up examination after endovascular intervention. Metal artifact reduction has been successfully demonstrated in coil mass cases, but only in a small series. We attempted to objectively and subjectively evaluate the feasibility of metal artifact reduction with various metallic objects and coil lengths. MATERIALS AND METHODS: We retrospectively reprocessed the flat detector CT data of 28 patients (15 men, 13 women; mean age, 55.6 years) after they underwent endovascular treatment (20 coiling ± stent placement, 6 liquid embolizers) or shunt drainage (n = 2) between January 2009 and November 2011 by using a metal artifact reduction correction algorithm. We measured CT value ranges and noise by using region-of-interest methods, and 2 experienced neuroradiologists rated the degrees of improved imaging quality and artifact reduction by comparing uncorrected and corrected images. RESULTS: After we applied the metal artifact reduction algorithm, the CT value ranges and the noise were substantially reduced (1815.3 ± 793.7 versus 231.7 ± 95.9 and 319.9 ± 136.6 versus 45.9 ± 14.0; both P < .001) regardless of the types of metallic objects and various sizes of coil masses. The rater study achieved an overall improvement of imaging quality and artifact reduction (85.7% and 78.6% of cases by 2 raters, respectively), with the greatest improvement in the coiling group, moderate improvement in the liquid embolizers, and the smallest improvement in ventricular shunting (overall agreement, 0.857). CONCLUSIONS: The metal artifact reduction algorithm substantially reduced artifacts and improved the objective image quality in every studied case. It also allowed improved diagnostic confidence in most cases. Abbreviations CCFcarotid cavernous fistulaFDCTflat detector CTMARmetal artifact reductionHUHounsfield unit