Gaseous ultrasound contrast media and method for selecting gases for use as ultrasound contrast media

Abstract

Disclosed herein are agents for enhancing the contrast in an ultrasound image. These agents are extremely small bubbles, or “microbubbles,” comprised of specially selected gases. The microbubbles described herein exhibit long life spans in solution and may be produced at a size small enough to traverse the lungs, thus enabling improved ultrasound imaging of the cardiovascular system and other vital organs. Also disclosed herein is a method for selecting gases from which contrast agents may be produced. The method is based on calculations using inherent physical properties of gases and describes a means to associate the properties of a gas with the time for dissolution of microbubbles comprised of the gas.

1 - 14 . (canceled)  
   
   
       15 . A biocompatible ultrasound contrast agent comprising microbubbles of a gas selected from the group consisting of perfluoropropane and other perfluorcarbons with a Q coefficient equal to or greater than 13, 154, where the Q coefficient represents the time for complete dissolution of a microbubble of said gas compared to the time for complete dissolution of a microbubble of air in the same solution.  
   
   
       16 . A biocompatible ultrasound contrast agent according to  claim 15   comprising microbubbles of perfluoropropane.    
   
   
       17 . A biocompatible ultrasound contrast agent according to  claim 15   comprising microbubbles of a perfluorocarbon gas with a Q coefficient of about 13, 154.    
   
   
       18 . A biocompatible ultrasound contrast agent according to  claim 15   comprising microbubbles of a gas selected from the group of perfluorocarbon gases with a Q coefficient greater than 13, 154.    
   
   
       19 . A biocompatible ultrasound contrast agent according to  claim 15   wherein said microbubbles are of a size sufficiently small so as to pass through capillaries of 8 micron diameter.    
   
   
       20 . A biocompatible ultrasound contrast agent according to  claim 15   wherein said microbubbles are suspended in a biocompatible aqueous formulation.    
   
   
       21 . A biocompatible ultrasound contrast agent according to  claim 15   further comprising a surfactant.    
   
   
       22 . A method of ultrasound imaging of a subject, comprising 
 providing to a subject an ultrasound contrast agent comprising microbubbles of a gas selected from the group consisting of perfluoropropane and other Perfluorocarbons with a Q coefficient equal to or greater than 13, 154, where the Q coefficient represents the tiem for complete dissolution of a microbubble of air in the same solution, and performing an ultrasound scan on said subject.    
   
   
       23 . A method according to  claim 22  in which the ultrasound contrast 
 agent comprises a collection of microbubbles.    
   
   
       24 . A method according to  claim 22  in which the ultrasound contrast 
 agent comprises free gas microbubbles.    
   
   
       25 . A method according to  claim 22  in which the ultrasound contrast 
 agent further comprises a surfactant.    
   
   
       26 . A method according to  claim 24  in which the ultrasound contrast 
 agent further comprises a surfactant.    
   
   
       27 . A method according to  claim 22  in which the ultrasound contrast 
 agent comprises microbubbles of a gas selected from the group of perfluorcarbon gases with a Q coefficient greater than 13, 154.    
   
   
       28 . A method according to  claim 22  in which the subject is a human.  
   
   
       29 . A method of ultrasound imaging of a subject, comprising providing 
 to said subject an ultrasound contrast agent comprising gaseous perfluorohexane and performing an ultrasound scan on said subject.    
   
   
       30 . A method according to  claim 29  in which the ultrasound contrast 
 agent comprises a collection of microbubbles.    
   
   
       31 . A method according to  claim 29  in which the ultrasound contrast 
 agent comprises free gas microbubbles.    
   
   
       32 . A method according to  claim 29  in which the ultrasound contrast 
 agent further comprises a surfactant.    
   
   
       33 . A method according to  claim 31  in which the ultrasound contrast 
 agent further comprises a surfactant.    
   
   
       34 . A method according to  claim 29  in which the subject is a human.