Magnetic Resonance Imaging Near Orthopaedic Hardware

Over one million total joint replacement surgeries were performed in the US in 2013 alone, and this number is expected to more than double by 2030. Traditional imaging techniques for post-operative evaluation of implanted devices, such as radiography, computerized tomography or ultrasound utilize ionizing radiation, suffer from beam hardening artifact, or lack the inherent high contrast necessary to adequately evaluate soft tissues around the implants, respectively. Magnetic resonance imaging (MRI), due to its ability to generate multi-planar, high contrast images without the use of ionizing radiation is ideal for evaluating peri-prosthetic soft tissues but has traditionally suffered from in-plane and through-plane data misregistration due to the magnetic susceptibility of implanted materials. A recent renaissance in the interest of imaging near arthroplasty and implanted orthopaedic hardware has led to the development of new techniques which help to mitigate the effects of magnetic susceptibility. This paper will describe the challenges of performing imaging near implanted orthopaedic hardware, how to generate clinically interpretable images when imaging near implanted devices, and how the images may be interpreted for clinical use. We will also describe current developments of utilizing MRI to evaluate implanted orthopaedic hardware.