BME MD/PhD candidate recognized by OSU's Graduate School

The Department of Biomedical Engineering wishes to congratulate MD/PhD candidate Travis Sharkey-Toppen and his advisor Dr. Subha V. Raman on being awarded the University’s Presidential Fellowship.  This fellowship is the most competitive and prestigious scholarly recognition awarded to students by the Graduate School.  It recognizes outstanding scholarship and research ability and provides awardees the opportunity to devote full time to their dissertation research.  Below is the abstract from Travis’ research proposal.

Travis Sharkey-Toppen’s Research Abstract

Plaque buildup, or atherosclerosis, affects the carotid arteries that supply the brain, and is the underlying disease causing 87% of all strokes. Severe blockage (stenosis) alone can significantly reduce blood flow to the brain; just as often, plaques with moderate stenosis may unexpectedly rupture with obstruction ensuing from clot formation. Too often, carotid atherosclerosis goes undetected until after an event. Surgery can remove the plaque, but is currently reserved for patients with obvious symptoms and severe stenosis. In patients with severe stenosis who have already had a stroke, surgery can reduce the risk of another event. However, the 5-year risk of stroke is as high as 12.4% in patients who lack recognizable symptoms and do not have sufficient stenosis to meet current surgical guidelines. Strategies to characterize plaque beyond the current paradigm of solely measuring stenosis severity could help detect such at-risk patients and ideally prevent their atherosclerotic events.

 Our team has pioneered in vivo characterization of iron in carotid plaque using magnetic resonance imaging (MRI). Using a MRI parameter that varies with the local magnetic field in tissues called T2*, we have been able to distinguish symptom-producing from non-symptom producing plaques in patients with carotid atherosclerosis. However, self-reported symptoms are insensitive to the burden of cerebral infarction (e.g. subclinical strokes) by neuroimaging. Ultrasound imaging is more widely available especially for screening, but cannot characterize tissue composition to the extent needed for patients with more advanced disease. Computed tomography (CT) reliably detects calcified plaque, but prior work indicates that calcium poorly predicts individual plaque events whereas iron may be a better marker of plaque instability. Thus, this state-of-the-art proposal addresses two important knowledge gaps. First, we will demonstrate that carotid artery plaque T2* is abnormal in patients with vs. those without signs of downstream injury by brain MRI. Second, we will demonstrate using MRI and CT imaging that iron, not calcium, is responsible for intraplaque T2* changes.  Together, these results will help further develop noncontrast MRI as a biomarker that helps clinical decision-making for at-risk patients.