Artifacts from Dental Casting Alloys in Magnetic Resonance                Imaging

Shafiei, Farhad; Honda, Eiichi; Takahashi, Hidekazu; Sasaki, Tomoaki

doi:10.1177/154405910308200806

Cited by 105 publications

(72 citation statements)

References 11 publications

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“…Metallic implants, such as stainless steel, Co-Cr alloys and Ti alloys, become magnetized in the strong magnetic field of the MRI instrument and produce artifacts on the image. 4) The areas that cause the artifacts on images are closely related to the magnetic susceptibility. 5) This susceptibility artifact is caused by metals, such as Ti, Co, and stainless steel, inside the body.…”

Section: Introductionmentioning

confidence: 99%

Magnetic Susceptibility of Zr-Cu Binary Alloys

Hong

Kim

2014

Mater. Trans.

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The objective of this study is to investigate the magnetic susceptibility of Zr-Cu binary alloys for their potential use as biomaterials with nullifying magnetic properties for magnetic resonance imaging diagnosis. The Zr-Cu binary alloys were prepared using the arc-melting process with zirconium strips and oxygen-free copper. This binary alloy has two dominant phases consisting of ¡-Zr and CuZr 2 intermetallic phase. The magnetic susceptibility of the Zr-Cu binary alloys was extremely low, approximately 10 ¹7 ; this level is approximately one order less than that of pure Zr and other commercialized metallic biomaterials. Consequently, Zr-Cu binary alloys have the potential to be used as biomaterials with low magnetic property.

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Section: Introductionmentioning

confidence: 99%

Magnetic Susceptibility of Zr-Cu Binary Alloys

Hong

Kim

2014

Mater. Trans.

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“…23 But, MRI diagnosis is inhibited with the presence of metallic implants in body because they become magnetized in the intense magnetic field of the MRI instrument, which causes artifacts on the image. 23,24 So devices with low magnetic susceptibility (v) are required. Compared to stainless steel, Co-Cr alloy, and titanium, zirconium has lower magnetic susceptibility and is more suitable for surgery performed in an MRI circumstance.…”

Section: Introductionmentioning

confidence: 99%

Microstructure, mechanical property, corrosion behavior, and in vitro biocompatibility of Zr–Mo alloys

et al. 2012

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In this study, the microstructure, mechanical properties, corrosion behaviors, and in vitro biocompatibility of Zr-Mo alloys as a function of Mo content after solution treatment were systemically investigated to assess their potential use in biomedical application. The experimental results indicated that Zr-1Mo alloy mainly consisted of an acicular structure of a 0 phase, while x phase formed in Zr-3Mo alloy. InZr-5Mo alloy, retained b phase and a small amount of precipitated a phase were observed. Only the retained b phase was obtained in Zr-10Mo alloy. Zr-1Mo alloy exhibited the greatest hardness, bending strength, and modulus among all experimental Zr-Mo alloys, while b phase Zr-10Mo alloy had a low modulus.

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“…According to the above-mentioned standard, magnetically induced torque has to be smaller than the product of the maximum device length and device weight, i.e., the mechanical torque T me due to gravity. Several medical products as surgical instruments or prosthetic heart valves have been examined for hazardous torque in the MR environment applying at least the limits in this standard (3)(4)(5)(6)(7)(8)(9)(10)(11)(12).…”

mentioning

confidence: 99%

Eddy‐current induction in extended metallic parts as a source of considerable torsional moment

Graf

Lauer

Schick

2006

Magnetic Resonance Imaging

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Purpose:To examine eddy-current-provoked torque on conductive parts due to current induction from movement through the fringe field of the MR scanner and from gradient switching. Materials and Methods:For both cases, torque was calculated for frames of copper, aluminum, and titanium, inclined to 45°to B 0 (maximum torque case). Conditions were analyzed in which torque from gravity (legal limit, ASTM F2213-02) was exceeded. Experiments were carried out on a 1.5 T and a 3 T scanner for copper and titanium frames and plates (Ϸ50 ϫ 50 mm 2 ). Movement-induced torque was measured at patient table velocity (20 cm/second). Alternating torque from gradient switching was investigated by holding the specimens in different locations in the scanner while executing sequences that exploited the gradient capabilities (40 mT/m). Results:The calculations predicted that movement-induced torque could exceed torque from gravity (depending on the part size, electric resistance, and velocity). Two experiments on moving conductive frames in the fringe fields of the scanners confirmed the calculations. For maximum torque case parameters, gradient-switching-induced torque was calculated to be nearly 100 times greater than the movement-induced torque. Well-conducting metal parts located off center vibrated significantly due to impulse-like fast alternating torque characteristics. Conclusion:Torque on metal parts from movement in the fringe field is weak under standard conditions, but for larger parts the acceptable limit can be reached with a high static field and increased velocity. Vibrations due to gradient switching were confirmed and may explain the sensations occasionally reported by patients with implants.

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Artifacts from Dental Casting Alloys in Magnetic Resonance Imaging

Cited by 105 publications

References 11 publications

Magnetic Susceptibility of Zr-Cu Binary Alloys

Magnetic Susceptibility of Zr-Cu Binary Alloys

Microstructure, mechanical property, corrosion behavior, and in vitro biocompatibility of Zr–Mo alloys

Eddy‐current induction in extended metallic parts as a source of considerable torsional moment

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