Assessment of MRI issues at 3-Tesla for metallic surgical implants: findings applied to 61 additional skin closure staples and vessel ligation clips

Abstract

PurposeMetallic skin closure staples and vessel ligation clips should be tested at 3-Tesla to characterize MRI issues in order to ensure patient safety. Therefore, metallic surgical implants were assessed at 3-Tesla for magnetic field interactions, MRI-related heating, and artifacts.MethodsA skin closure staple (Visistat Skin Stapler, staple, Polytetrafluoroethylene, PTFE, coated 316L/316LVM stainless steel; Teleflex Medical, Durham, NC) and a vessel ligation clip (Hemoclip Traditional, stainless steel; Teleflex Medical, Durham, NC) that represented the largest metallic sizes made from materials with the highest magnetic susceptibilities (i.e., based on material information) among 61 other surgical implants (52 metallic implants, 9 nonmetallic implants) underwent evaluation for magnetic field interactions, MRI-related heating, and artifacts using standardized techniques. MRI-related heating was assessed by placing each implant in a gelled-saline-filled phantom with MRI performed using a transmit/receive RF body coil at an MR system reported, whole body averaged SAR of 2.9-W/kg for 15-min. Artifacts were characterized using T1-weighted, SE and GRE pulse sequences.ResultsEach surgical implant showed minor magnetic field interactions (20- and 27-degrees, which is acceptable from a safety consideration). Heating was not substantial (highest temperature change, ≤ 1.6°C). Artifacts may create issues if the area of interest is in the same area or close to the respective surgical implant.ConclusionsThe results demonstrated that it would be acceptable for patients with these metallic surgical implants to undergo MRI at 3-Tesla or less. Because of the materials and dimensions of the surgical implants that underwent testing, these findings pertain to 61 additional similar implants.

The effect of 3 T MRI on microleakage of amalgam restorations

“…composed of precious (Au, Ag, Pt) and non-precious (Cr, Co, Mo, Ni, Ti) metals, alloys, amalgams, pure gold fillings, are often located in the orofacial region, and in vitro tests have been designed to characterize the properties of these materials to ensure patient safety. 4,[16][17][18][19] Although fixed dental prostheses, amalgam restorations and orthodontic appliances can produce image distortions on MRI scans of the face, they exhibit minimal deflection in a static magnetic field and are thus regarded as safe for MRI. 15 Dental amalgam has been an accepted part of dental treatment for nearly two centuries.…”

In Vitro Magnetic Resonance Imaging Evaluation of Ossicular Implants at 3 T

“…Deflection angles for each ossicular implant were assessed at the point of the highest spatial magnetic gradient for the 3-T MR system (26Y28). The highest ''patient accessible'' spatial gradient magnetic field for the 3-T MR scanner used in this investigation is 720 G/cm and occurs at an off-axis position that is 74 cm from isocenter of the MR system (26,27,29). The maximum deflection angle from the vertical direction to the nearest 1 degree was measured 3 times for each ossicular implant, and an average value was calculated (26Y28).…”

“…In consideration of the materials and dimensions of the implants that underwent testing, these findings pertain to many other similar ossicular implants from the same manufacturer that have smaller sizes and are made from materials with lower magnetic susceptibilities (25), thus expanding the MRI information for many other devices. This same strategy of MRI testing for implants has been successfully applied to aneurysm clips and hemostatic clips (26,27).…”

Polymer film-nanoparticle composites as new multimodality, non-migrating breast biopsy markers

“…While titanium markers elicit small MRI susceptibility artefacts that may serve as biopsy site identifiers if sufficient in size, artefacts caused by stainless steel markers may be unacceptably large, potentially obscuring pathologically relevant areas surrounding the biopsy site [9][10][11]. The latter case is likely to become increasingly problematic as higher fieldstrength magnets are introduced into more clinical institutions [12][13][14]. Furthermore, US visibility of these metal markers is limited.…”