[Influence of sequence type on the extent of the susceptibility artifact in MRI--a shoulder specimen study after suture anchor repair].
OBJECTIVE
To compare the extent of susceptibility artifacts after metallic suture anchor implantation by analyzing 14 different MRI sequences.


METHODS
A metallic suture anchor was implanted in the central area of three glenoid porcine specimens. The specimens were imaged with a 1.5 T scanner using a protocol of 14 standard sequences including gradient echo, spin echo and turbo spin echo sequences with and without fat-saturation. Artifact size was measured for each specimen and sequence. The resulting mean artifact areas were determined for each type of sequence and the mean values of the three specimens compared.


RESULTS
Gradient echo-sequences produced significantly larger artifact areas than the spin echo and turbo spin echo sequences, whereby the artifacts of the 3D-gradient echo sequences were smaller than the artifacts of the 2D-gradient echo sequences. A turbo spin echo sequence with a high readout band width and a short effective echo time showed the best results. For the conventional spin echo sequence, a reduction in the echo time did not significantly decrease the artifact size. Spectral fat-saturation did not affect the area of the susceptibility artifact compared to the non-saturated sequence.


CONCLUSIONS
Gradient echo sequences should not be used after metallic suture anchor repair. Turbo spin echo sequences showed a decrease in the artifact size compared to conventional spin echo sequences and should be performed with a short effective echo time and a high band width. Spectral fat- saturation did not increase the artifact size significantly.
Herold
T
T
Institut für Röntgendiagnostik, Klinikum der Universität Regensburg. thomas.herold@klinik.uni-regensburg.de
Caro
W C
WC
Heers
G
G
Perlick
L
L
Grifka
J
J
Feuerbach
S
S
Nitz
W
W
Lenhart
M
M
D000818:Animals; D016477:Artifacts; D017352:Echo-Planar Imaging; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008670:Metals; D012782:Shoulder; D013537:Sutures; D013552:Swine
D008670:Metals