ABSTRACT
Orthopedic hardware should not be considered a contraindication to computed tomography
(CT) or magnetic resonance (MR) imaging. The hardware alloy, the geometry of the hardware,
and the orientation of the hardware all affect the magnitude of image artifacts. For
commonly encountered alloys, the severity of image artifacts is similar for CT and
MR. Cobalt chrome or stainless steel hardware produces the most artifacts; titanium
hardware produces the least. In general, image artifacts are most severe adjacent
to the hardware. CT image artifacts are related to incomplete X-ray projection data
resulting in streaks. These can be mitigated by increasing scan technique and using
a smoother reconstruction filter. Hardware with a rectangular cross-sectional shape
such as a fixation plate will cause more artifacts than a radially symmetrical device
such as an intramedullary nail. Image artifacts at MR are caused by the hardware magnetic
susceptibility and the induction of eddy currents within the metal. A turbo spin-echo
sequence yields the best results. The use of larger image matrices, thinner slices,
and a wide receiver bandwidth are recommended parameter adjustments when imaging patients
with hardware. This article discusses how hardware-related artifacts can be minimized
by altering scan technique and image reconstruction.
KEYWORDS
Tomography - X-ray computed - magnetic resonance imaging - joint prostheses - orthopedic
fixation devices
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Kenneth A BuckwalterM.D.
Department of Radiology, Indiana University Hospital
550 N. University Blvd., Rm. 0663, Indianapolis, IN 46202
Email: kbuckwal@iupui.edu
