MRI Near Metal

The presence of metal can be a serious problem in MRI, because (1) Magnetic metals can experience a force in the scanner, (2) Long wires (such as in pacemakers) can result in induced currents and heating from the RF magnetic field and (3) Metals cause the static (B0) magnetic field to be inhomogeneous, causing severe image degradation.

The first two of these problems are a DANGER to the patient, and are cause to not do an MRI. The third is not dangerous, but can result in severely distorted images using conventional MRI.

Metallic implants are increasingly common in medicine, including dental fillings, stents, joint replacements, spinal fixation, and many more. However, complications can arise when implants are used, and there are not always good methods for imaging to assess these complications.

We are addressing the inhomogeneity problem by developing distortion-free MR imaging near MR-safe implants. Using additional encoding, it is possible to dramatically improve the images, as shown in this example of a person with metal screws in his knee.   Although these methods are now being made commercially available, we continue to improve the speed, flexibility and resolution of MRI near metal.

Relevant Publications