Metallic artifacts on MR images of the postoperative spine: reduction with fast spin-echo techniques.

Tartaglino, L M; Flanders, Adam E.; Vinitski, Simon; Friedman, David P.

doi:10.1148/radiology.190.2.8284417

Cited by 126 publications

(62 citation statements)

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“…In these regions, spins with different frequencies predominate and lead to signal losses and image distortion. 4,15,19 Moreover, all metals, including nonmagnetic ones, may act as electrical conductors, causing an additional effect. 2 This problem is of particular importance when the diagnostic aim is to assess implant positioning, implant shape, and the implant-bone interface.…”

Section: Implants and Mr Artifactmentioning

confidence: 99%

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Postoperative magnetic resonance imaging artifact with cobalt-chromium versus titanium spinal instrumentation

Ahmad¹,

Sidani

Fourzali

et al. 2013

SPI

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Object Cobalt-chromium alloy (CoCr) rods haves some preferred biomechanical properties over titanium rods for spinal fixation. The use of CoCr rods in spinal fusion is relatively new, and there is no study in the existing world literature assessing the artifact caused by these rods in patients undergoing postoperative MRI. The purpose of this study is to compare the amount of imaging artifact caused by these implants and to assess its impact on the visualization of neighboring neural structures. Methods This study investigated MR images in patients who underwent implantation of thoracolumbar instrumentation using 5.5-mm-diameter CoCr rods between November 2009 and March 2011 and images obtained in a comparison group of patients who had 5.5-mm titanium rods implanted during the same time period. Axial measurements of the artifact created by the rods between the screw heads were compared between the groups. Two blinded board-certified radiologists performed the measurements independently. They scored the visualization of the spinal canal using a subjective scoring system of 1–3, with 1 representing very good visualization and 2 and 3 representing reduced (good or suboptimal, respectively) visualization as a result of rod-related artifact. All measurements and scores were independently provided for T1-weighted and T2-weighted fast spin echo sequences (1.5-T magnet, 5-mm slice thickness). Results A total of 40 levels from the CoCr group (6 patients) and 30 levels from the titanium group (9 patients) were included in the analysis. Visualization of the canal at all levels was rated a score of 1 (very good) by both evaluators for both the CoCr and titanium groups. The average artifact on T1-weighted images measured 11.8 ± 1.8 mm for the CoCr group and 8.5 ± 1.2 mm for the titanium group (p < 0.01). The corresponding measurements on T2-weighted images were 11.0 ± 2.3 mm and 8.3 ± 1.7 mm (p < 0.01), respectively. In a mixed regression model, the mean artifact measurement for the CoCr group was, on average, 3.5 mm larger than for the control group. There was no significant difference between the measurements of the 2 evaluators (p = 0.99). Conclusions The artifact caused by CoCr rods is approximately 3.5 mm larger than that caused by titanium rods on axial T1- and T2-weighted MRI. However, artifact from either CoCr or titanium was not found to interfere with the evaluation of the spinal canal and surrounding neural elements.

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Section: Implants and Mr Artifactmentioning

confidence: 99%

“…10,15,19,20,22,23 Some alloys, such as stainless steel, produce significant artifact, and the MR images can be practically useless for interpretation. Others, such as titanium alloys, produce acceptable artifact and allow acceptable image quality in most instances.…”

mentioning

confidence: 99%

Postoperative magnetic resonance imaging artifact with cobalt-chromium versus titanium spinal instrumentation

Ahmad¹,

Sidani

Fourzali

et al. 2013

SPI

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“…FSE imaging sequences employ multiple sequential refocusing 180°pulses in acquiring multiple lines of information (K-space data) within a single repetition time (TR): it refocuses spins at a faster interval than with conventional spin echo imaging, causing a small reduction in diffusion-related signal loss. This effect may be increased further, resulting in artifact reduction, with the [16,29,30]. FSE also reduces artifact arising from malrotation [31], which is a relatively small contributor to signal loss around metal.…”

Section: Pulse Sequence Selectionmentioning

confidence: 99%

Metal-related artifacts in instrumented spine. Techniques for reducing artifacts in CT and MRI: state of the art

et al. 2009

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The projectional nature of radiogram limits its amount of information about the instrumented spine. MRI and CT imaging can be more helpful, using cross-sectional view. However, the presence of metal-related artifacts at both conventional CT and MRI imaging can obscure relevant anatomy and disease. We reviewed the literature about overcoming artifacts from metallic orthopaedic implants at high-field strength MRI imaging and multi-detector CT. The evolution of multichannel CT has made available new techniques that can help minimizing the severe beam-hardening artifacts. The presence of artifacts at CT from metal hardware is related to image reconstruction algorithm (filter), tube current (in mA), X-ray kilovolt peak, pitch, hardware composition, geometry (shape), and location. MRI imaging has been used safely in patients with orthopaedic metallic implants because most of these implants do not have ferromagnetic properties and have been fixed into position. However, on MRI imaging metallic implants may produce geometric distortion, the so-called susceptibility artifact. In conclusion, although 140 kV and high milliamperage second exposures are recommended for imaging patients with hardware, caution should always be exercised, particularly in children, young adults, and patients undergoing multiple examinations. MRI artifacts can be minimized by positioning optimally and correctly the examined anatomy part with metallic implants in the magnet and by choosing fast spin-echo sequences, and in some cases also STIR sequences, with an anterior to posterior frequencyencoding direction and the smallest voxel size.

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“…Wang et al report that it is possible to obtain high-quality MR scans with minimal metal artifact in both the T1-and T2-weighted modes by using appropriate settings [16]. Fast spin echo imaging, in particular, decreases the metallic artifacts [12,15].…”

Section: Discussionmentioning

confidence: 99%

MR imaging for early complications of transpedicular screw fixation

Çolak

Kutlay

Demircan

et al. 1999

European Spine Journal

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Metallic artifacts on MR images of the postoperative spine: reduction with fast spin-echo techniques.

Abstract: FSE imaging, especially when performed with shorter echo spacing, increases the amount of T2-weighted information in the presence of metallic artifact because it decreases magnetic susceptibility effects.

Cited by 126 publications

References 0 publications

Postoperative magnetic resonance imaging artifact with cobalt-chromium versus titanium spinal instrumentation

Postoperative magnetic resonance imaging artifact with cobalt-chromium versus titanium spinal instrumentation

Metal-related artifacts in instrumented spine. Techniques for reducing artifacts in CT and MRI: state of the art

MR imaging for early complications of transpedicular screw fixation

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