OCTOBER 2012

SMRT HOMESTUDIES: A PHYSICS PRESENTATION

Anne M. Sawyer, B.S., R.T. (R)(MR)
Editor, SMRT Home Studies
 “ . . . the term ‘gradient echo sequence’ is somewhat unspecific, as even images acquired with the most common sequences employing the gradient echo for data acquisition can significantly differ in signal, contrast, artifact behavior, and sensitivity to, eg, flow. This is due to the different use of sequence timing and basic sequence building blocks such as spoiler gradients or specific radiofrequency (RF) pulse phase patterns.”
We are pleased to present the SMRT Educational Seminars, Volume 15, Number 3: “MR Physics: Gradient Echo & Parallel Imaging.” This is the 57th accredited home study developed by the SMRT, exclusively for SMRT members. The accreditation is conducted by the SMRT acting as a RCEEM (Recognized Continuing Education Evaluation Mechanism) for the ARRT. Category A credits are assigned to each home study, which can be used to maintain one’s ARRT advanced registry. SMRT home studies are also accredited for AIR (Australian Institute of Radiography), NZIMRT (New Zealand Institute of Radiation Technology) and CPD Now (The College of Radiographers, United Kingdom) continuing professional development (CPD) activities.

Two articles have been selected for this SMRT home study. The first article is an inclusive review of gradient echo MR imaging from the basics to recent updates in rapid imaging. The second article is a thorough yet straightforward discussion of parallel imaging including an in-depth explanation of the methods utilizing multiple array RF coils and k-space traversal in order to reduce scan time.

As stated by the authors of the first article, “ . . . the term ‘gradient echo sequence’ is somewhat unspecific, as even images acquired with the most common sequences employing the gradient echo for data acquisition can significantly differ in signal, contrast, artifact behavior, and sensitivity to, eg, flow. This is due to the different use of sequence timing and basic sequence building blocks such as spoiler gradients or specific radiofrequency (RF) pulse phase patterns.” In our never-ending pursuit of faster imaging, gradient echo MR sequences continue to develop and advance in ways that require additional education and training for the technologist and radiographer to effectively utilize in clinical and research imaging.

The authors of the second article maintain “ . . . the primary disadvantage of MRI is that it requires a relatively long time to capture all of the data needed to make an image as compared to computed tomography (CT) or ultrasound.” And, “The advent of parallel imaging has changed the way MRI is used in the clinic. Parallel imaging is a robust way to accelerate MRI data acquisition.” As with so many MRI techniques, it is necessary for us as technologists and radiographers to understand the design and implementation of the sequences in order to use them successfully including the elimination of sequence-specific artifacts.

Many thanks to Nancy Hill Beluk from Pittsburgh, Pennsylvania, USA, for acting as our Expert Reviewer for this home study issue; and the accompanying quiz that provides the assigned continuing education credits. Thanks also to Heidi Berns, M.S., R.T.(R)(MR), FSMRT, Chair of the SMRT RCEEM Ad-hoc committee from Coralville, Iowa, USA and all those who participate on this committee by reviewing the home studies for accreditation. Finally, thanks to Jennifer Olson, Associate Executive Director, Mary Keydash, Publications Director, and the entire staff in the Berkeley, California, USA office of the ISMRM and SMRT for their insight and long hours spent supporting these educations symposia.

We would also like to thank John Wilkie and all of the individuals at Invivo Corporation (Philips Healthcare) who generously support our home studies program. Their continuing investment advances technologist and radiographer knowledge and brings quality continuing education to the SMRT membership worldwide.