1. Unidad Avanzada de Investigación y Diagnostico Ecográfico y Renal, Clínica Puerto Ordaz, Puerto Ordaz, Venezuela
2. U.O.C. di Nefrologia e Dialisi, Ospedale Sant’Anna, Azienda Ospedaliera Sant’Anna, Como, Italy
3. Department of Health Sciences, University of Milan, Milan, Italy
4. Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, AB, Canada
5. Department of Radiology, Emory University, Atlanta, GA, USA