1. Center for Ultrasound Molecular Imaging and Therapeutics, Department of Medicine & Heart and Vascular Institute, University of Pittsburgh School of Medicine and University of Pittsburgh Medical Center (UPMC), Pittsburgh, Pennsylvania 15261, USA
2. Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, USA
3. McGowan Institute for Regenerative Medicine, University of Pittsburgh and UPMC, Pittsburgh, Pennsylvania 15219, USA