Pitfalls in quantitative contrast echocardiography: the steps to quantitation of perfusion.
Wiencek JG, Feinstein SB, Walker R, Aronson S. Pitfalls in quantitative contrast echocardiography: the steps to quantitation of perfusion. J Am Soc Echocardiogr. 1993 Jul-Aug; 6(4):395-416.