Open AccessQuantification of metal‐induced susceptibility artifacts associated with ultrahigh‐field magnetic resonance imaging of spinal implants
Author(s) -
Chiba Yusuke,
Murakami Hideki,
Sasaki Makoto,
Endo Hirooki,
Yamabe Daisuke,
Kinno Daichi,
Doita Minoru
Publication year - 2019
Publication title -
jor spine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.125
0ISSN - 2572-1143
DOI - 10.1002/jsp2.1064
Subject(s) - artifact (error) , magnetic resonance imaging , spin echo , materials science , biomedical engineering , titanium , rod , titanium alloy , nuclear magnetic resonance , gradient echo , nuclear medicine , medicine , radiology , alloy , physics , alternative medicine , pathology , metallurgy , composite material , neuroscience , biology
Reports on spinal‐implant metallic artifacts in 7‐T magnetic resonance imaging (MRI) are lacking. Thus, we investigated the magnitude of metal artifacts derived from spinal implants in 7‐T MRI and analyzed the differences obtained with spinal rods manufactured from pure titanium, titanium alloy, and cobalt‐chrome (5.5‐mm and 6.0‐mm diameters and 50‐mm length). Following the American Society for Testing and Materials guidelines, we measured the artifact size and artifact volume ratio of each rod during image acquisition using 7‐T MRI scanners with three‐dimensional (3D) T1‐weighted and 3D T2* spoiled gradient echo (GRE), 3D T2‐weighted fast spin echo, zero echo time (ZTE), and diffusion‐weighted imaging sequences. Pure titanium and titanium alloy rods yielded significantly smaller artifacts than did cobalt‐chrome rods, with no significant difference between pure titanium and titanium alloy rods. The artifact sizes of the 5.5‐mm and 6.0‐mm diameter rods were similar. The artifact magnitude increased in the following sequence order: ZTE, 3D T2 fast spin echo, 3D T1 spoiled GRE, 3D T2* spoiled GRE, and diffusion‐weighted imaging. Artifacts obtained using the spin echo method were smaller than those obtained with the GRE method. Because the echo time in ZTE is extremely short, the occurrence of artifacts because of image distortion and signal loss caused by differences in magnetic susceptibility is minimal, resulting in the smallest artifacts. ZTE can be a clinically useful method for the postoperative evaluation of patients after instrumentation surgery, even with 7‐T MRI.