In 1983, Pettigrew undertook a position as clinical research scientist at Picker International, Inc., where he began work in developing nuclear magnetic resonance imaging, later called MRI, specifically for the heart. Picker was the first company to manufacture an
MRI scanner, and Pettigrew helped develop their technology for cardiovascular imaging. Of the first 10 Picker MRI scanners installed worldwide, Pettigrew co-developed, along with A.V. Lakshminarayanan, and installed the cardiac imaging software on all of these systems. These included the first units at the
Mayo Clinic, Wake Forrest University, and the
NIH Clinical Center and several systems in Europe. In 1984, Pettigrew received a fellowship from the
Robert Wood Johnson Foundation (RWJF) in their Harold Amos Medical Faculty Development Program, created to help achieve more appropriate representation and inclusion of minority scientists and scholars in academia. As an RWJF fellow, he moved to
Emory University School of Medicine in the Department of Radiology and continued his work in developing non-invasive cardiovascular imaging employing nuclear medicine and MRI. At Emory, he partnered with scientists at
Philips Medical Systems to develop the first industrial cardiovascular MRI software package (Philips Cardiac Package, 1988). In 1989, when the
Radiological Society of North America (RSNA) held its Diamond Jubilee 75th Anniversary meeting, then hailed as the largest medical meeting in the world, Pettigrew delivered the invited keynote, the Eugene Pendergrass New Horizons Lecture. This talk, titled
Four Dimensional Cardiac MRI: Diagnostic Procedure of the Future, predicted the advanced medial technological approach being realized and built upon today. In the 1990s, through appointments as professor in the Department of Cardiology at the Emory University School of Medicine, where he directed the Emory Center for Magnetic Resonance Research, and in the Department of Bioengineering at the
Georgia Institute of Technology, his research continued to focus on applying MRI to the diagnosis of a variety of cardiac disorders, quantifying heart-wall function, imaging coronary arteries, and in quantifying blood flow across heart valves and in vessels, including congenital heart anomalies. ==Transition to NIH==