Cranial bone flap fixation clamps: compatibility at MR imaging.

Abstract

Metallic cranial bone flap fixation clamps were tested for compatibility at 1.5-T magnetic resonance (MR) imaging with standardized techniques. There was no magnetic field attraction, heating was minor, and artifacts involved a relatively small signal void. These data indicate that bone flap fixation clamps will not present risks to patients undergoing MR imaging procedures with MR systems of 1.5 T or less.

Rivet-like titanium clamp fixation of cranial bone flaps during open magnetic resonance-guided neurosurgery

“…Like mini-plates, burr-holes can be covered using larger clamps of 16 mm diameter. According to the findings of Shellock & Shellock 17 MRI of the brain will not substantially be affected by the presence of titanium bone flap clamps. On the basis of cross-sectional areas, the fast spoiled gradient sequences produced the largest artefacts, followed by T1-weighted fast SE sequences.…”

“…The predominant safety concern is that the implant may not be moved. 17,[23][24][25][26][27] Movement of metallic implants is the result of a translational force, which is proportional to the strength of the magnetic field, and a torque force, which attemps to align or rotate the object parallel to the static magnetic field. 23,28,29 Translational force causes the highest potential risk to a patient and occurs at the position in the MRI system where the inhomogeneous magnetic fields are the greatest, close to the entrance and at the exit of the magnets bore.…”

“…However, gradient-echo pulse sequences may produce slightly larger artefacts that limit the diagnostic capacity, if the pathological condition is located within a few millimeters to the clamp. 17 Therefore, alternative pulse sequences can be used to minimize metal-related artefacts associated with gradient-echo MRI. 27,30 Metallic bone flap fixation clamps made from titanium alloy do not represent a hazard to patients undergoing MRI at 1.5 T or less.…”

“…They will not present risks to patients undergoing MRI procedures with MR systems of 1.5 T or less. 17 The fixation system itself and its surgical application during MRI-guided neurosurgical procedures in a vertical open MR scanner is described.…”

A new method for surgical repair of impression fractures of the cranial vault and frontal sinus with rivet-like titanium clamps

“…The CT and MRI compatibility of titanium clamps and miniplates due to artifacts is absolutely identical [8]. Experiments in a 1.5 T MR tomograph with titanium clamps revealed no magnetic field attraction and that heating was minor and artifacts involved a relatively small signal void [14]. Table 2 compares the advantages and disadvantages of titanium clamps and miniplates.…”