Techniques for reducing metal artifacts in magnetic resonance imaging (MRI) of orthopaedic implants have seen tremendous improvement in the last decade. Extensions of these technologies to other applications, including brain imaging, remain under-developed. As a result, MRI contrasts essential for neuroimaging ? such as T2-FLAIR weighting, weighting, diffusion weighting, and angiography ? have not been actively explored. At the same time, intra-cranial implants or devices which are safe to image have proliferated, and a growing number of neuroimaging exams include metal artifacts which render them non-diagnostic. It is the goal of this work to develop and optimize metal artifact reduced acquisitions for the deployment of a fully-functioning neuroimaging clinical exam. The ?rst aim of the proposed work seeks to develop acquisitions and reconstructions for MRI contrasts which are needed for neuroimaging exams, and are not yet available. Currently available contrasts include T1-weighting, T2-weighting, and in a preliminary format, diffusion-weighting. For application to neuroimaging, similar metal artifact reduction principles will be leveraged to yield T2-FLAIR, -weighted, and angiographic acquisitions. Novel principles necessary for the development of the new proposed acquisitions have recently been demonstrated within the context of projects targeting orthpaedic implants. In this proposal, these new developments will be translated to address neuroimaging-speci?c applications.
The second aim of the proposed study seeks to evaluate existing and new metal artifact reduction acquisi- tions for diagnostic performance in neuroimaging exams. Several quantitative metric comparisons between the conventional and proposed neurological MRI exams will be performed. Compared metrics will include artifact volume, signal to noise, and contrast to noise. Finally, the diagnostic performance of the newly proposed metal artifact mitigated neurological MRI exam will be evaluated in a randomized reader study. Completion of the proposed work could yield foundational technology necessary for a complete metal artifact reduced neurological MRI examination. Within the current study, this technology will be developed and tested to the point of appropriateness for future clinical trials to assess its performance as a primary diagnostic tool. Ultimately, this work will lead to the availability of new diagnostic neurological MRI exams in patients where current technologies yield non-diagnostic MRI data.
This proposal will bring advanced MRI capabilities to patients with cranial metallic implants who need diagnostic neurological imaging. Compared to the current standard of care methods using computed tomography imaging methods, patients with ventricular shunts, aneurysm coils, arterial ?ow diverters, dental appliances, cochlear implants, and other metallic implants in their heads, metal artifact reduced MRI offers no risks of ionizing ra- diation and improved contrast within brain tissues of interest. The proposed neuroimaging-focused translation and development of novel MRI principles, originally developed for imaging around orthopaedic implants, offers transformative potential for patients with neurological disorders and implants in or near their skulls.
