Clinical Implementation of MRI of Joint Arthroplasty

Abstract

MRI near TJA is effective with appropriate imaging protocols and standardized safety precautions. Strict adherence to MR Conditional labeling may preclude broad use of MRI for TJA assessment.

Multispectral diffusion‐weighted imaging near metal implants

“…The safety of 2D-FSE and 3D-MSI techniques for assessing total joint replacements has been established in large-cohort clinical studies (29). In the experiments reported here, the reported local specific absorption rate values for 2D-MSI PROPELLER DSB DWI were at or below the levels reported for conventional 2D-FSE techniques acquired in the same exams.…”

Advanced MRI Techniques for the Hip Joint: Focus on the Postoperative Hip

“…The challenge of arthroplasty imaging is that the magnetic susceptibility generated from the metal prosthesis alters the regional static magnetic field, thereby changing local precessional frequencies [2]. This results in field inhomogeneities that distort regional anatomy and reallocate signal from its proper position to overlie like frequency spins, generating areas of signal pileup around areas of signal loss [3, 4], with resultant misregistration artifacts in both the slice selection and readout directions during signal encoding [2, 5].…”

“…This results in field inhomogeneities that distort regional anatomy and reallocate signal from its proper position to overlie like frequency spins, generating areas of signal pileup around areas of signal loss [3, 4], with resultant misregistration artifacts in both the slice selection and readout directions during signal encoding [2, 5]. Metallic implants also accelerate proton dephasing, which degrades the periprosthetic signal [6].…”

“…In addition, because susceptibility artifact is inversely proportional to the magnetic field frequency-encoding and slice select gradient strengths, increasing the gradient amplitudes will decrease susceptibility artifact. Consequently, using a wider receiver bandwidth and a smaller voxel size, which minimizes variation and dephasing within a single voxel, will increase the frequency-encoding and slice select gradient amplitudes, thereby decreasing distortion and improving spatial resolution [2–4]. Moreover, adjusting the direction of the frequency-encoding gradient to run along the long axis of the arthroplasty will diminish susceptibility artifact even further [6].…”

Using Nuclear Medicine Imaging Wisely in Diagnosing Infectious Diseases

“…Recent metal suppression techniques such as multiacquisition with variable-resonance image combination or slice encoding for metal artifact correction have been used by specific producers of MRI machines and have greatly reduced the artifact abnormalities seen with older MRI machines, allowing for greater resolution and improved diagnosis of hardware failure with or without infection [20, 21]. However, not all imaging centers and hospitals have adopted such techniques, and nuclear medicine modalities may provide an option that is equally or more accurate.…”