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Motion-Robust Super-resolution Magnetic Resonance Imaging

Tutorial at ISBI2013

MOTIVATION

Technical innovations overcoming the limitations of existing medical imaging technology will enable improved diagnosis, monitoring and therapeutic intervention assessment in medicine. Ultimately, it will offer better clinical care for patients. Magnetic resonance imaging (MRI) is a non-invasive imaging modality that generates a unique range of contrast to evaluate many organs, structures, and anomalies in vivo. The use of MRI, however, has been limited mainly by two factors: the relatively low spatial resolution achievable and its sensitivity to motion. .2

The sensitivity to motion makes it highly challenging to acquire good quality scans when imaging newborns, children and non-cooperative patients. In clinical practice, sedation and anesthesia can be used but lead to significantly increased risks, burden and costs. Poorly cooperative subjects for which there is no clear direct benefit justifying the sedation cannot generally be imaged. Novel developments in research are necessary to enable high quality scans in presence of motion.

 Motion robust fetal imaging

The other major limitation of MRI is its spatial resolution which is often chosen relatively low in a compromise to achieve high signal-to-noise ratio (SNR). Acquisition of high spatial resolution MRI with high SNR requires that the patient or the organ remains completely still in the scanner for an extensive period of time. High resolution in-vivo MRI is strongly challenged by the susceptibility of MRI to motion. The problems of motion and resolution in MRI are inter-connected: motion robust imaging enables longer acquisitions to improve the resolution, while resolution enhancement techniques can be used to image at conventional resolution with faster scans, reducing the impact of motion.

Extensive research has been carried out for motion compensation and also for resolution enhancement in MRI; however, these problems have rarely been considered together. The recent literature suggests that images of moving subjects and moving organs may be obtained at high spatial resolutions using integrated motion-robust super-resolution reconstruction. Motion-robust super-resolution MRI can reduce the risk and the cost of MRI by reducing the rate of sedation and repeated acquisitions and may significantly increase the capability and capacity of MRI in clinical evaluation as well as in research studies. This motivates a tutorial that will expose the recent developments in the field.

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