Myocardial perfusion imaging with contrast ultrasound – state of the art – Thomas R.Porter, Feng Xie J Am Coll Cardiol Imag 2010, Vol3, No2, 176-187 Long – term prognostic value of dipyridamole stress myocardial contrast echocardiography Paulina Wejner-Mik et al., European Journal of Echocardiography (2011) 12, 762 – 766