Systems and method of delivering fluids to a patient of varying concentration

Abstract

A method for injection of an imaging contrast into a patient, includes: a. in a first phase, injecting a fluid having a first concentration of contrast agent for a first period of time; and b. in a second phase, injecting a fluid having a second concentration of contrast agent for a second period of time. The osmolarity of the second phase is higher than the osmolarity of the first phase. In several embodiments in which the contrast agent of the first phase is of the same composition as the contrast agent of the second phase, the second concentration can be higher than the first concentration. The first phase can, for example, precede the second phase. The method can further include: c. in a third phase, subsequent to the second phase, injecting a fluid having a third concentration of contrast agent for a third period of time. The osmolarity of the third phase is lower than the osmolarity of the second phase. In embodiments in which the composition of the contrast agent of the third phase is the same as the composition of the contrast agent of the second phase, the third concentration can be lower than the second concentration. The fluid injected in the first phase can, for example, be closer to the osmolarity of blood that the fluid injected in the second phase and can even be generally iso-osmolar to blood plasma (for example, within 20% or even 10% or less of the osmolarity of blood plasma of the patient). Likewise, the fluid injected in the third phase can be closer to the osmolarity of blood plasma that the fluid injected in the second phase and can even be generally iso-osmolar to blood.

1 - 50 . (canceled) 
     
     
         51 . A method for injection of an imaging contrast into a patient, comprising:
 a. in a first phase, injecting a fluid having a first concentration of contrast agent for a first period of time, wherein the first concentration of contrast agent includes contrast;   b. in a second phase, subsequent to the first phase, injecting a fluid having a second concentration of contrast agent for a second period of time, the second concentration being higher than the first concentration of contrast agent; and   c. in a third phase, subsequent to the second phase, injecting a fluid having a third concentration of contrast agent for a third period of time, the third concentration being lower than the second concentration of contrast agent, wherein the third concentration of contrast agent includes contrast,   wherein each of the first phase, the second phase, and the third phase proceed according to a set of injection parameters, including at least one of injection flow rate, injection volume, and injection duration, determined in advance of the first phase.   
     
     
         52 . The method of claim  1  wherein the fluid injected in the first phase is generally iso-osmolar to blood plasma. 
     
     
         53 . The method of claim  1  wherein the fluid injected in the first phase has a viscosity that is approximately equal to the viscosity of a physiological saline solution or of blood plasma. 
     
     
         54 . The method of claim  1  wherein the fluid injected in the first phase has a lower viscosity than the fluid injected in the second phase. 
     
     
         55 . The method of claim  2  wherein the fluid injected in the first phase has an osmolarity within 20% of the osmolarity of the patient's blood. 
     
     
         56 . The method of claim  2  wherein the fluid injected in the first phase has an osmolarity within 10% of the osmolarity of the patient's blood. 
     
     
         57 . The method of claim  2  wherein the fluid injected in the third phase is generally iso-osmolar to blood plasma. 
     
     
         58 . The method of claim  7  wherein the osmolarity of the third phase is within 20% of the osmolarity of the patient's blood. 
     
     
         59 . The method of claim  7  wherein the osmolarity of the third phase is within 10% of the osmolarity of the patient's blood. 
     
     
         60 . The method of claim  5  wherein the osmolarity of the third phase is within 20% of the osmolarity of the patient's blood. 
     
     
         61 . The method of claim  6  wherein the osmolarity of the third phase is within 20% of the osmolarity of the patient's blood. 
     
     
         62 . The method of claim  5  wherein the osmolarity of the third phase is within 10% of the osmolarity of the patient's blood. 
     
     
         63 . The method of claim  6  wherein the osmolarity of the third phase is within 10% of the osmolarity of the patient's blood. 
     
     
         64 . The method of claim  1  wherein the first concentration and the third concentration are approximately equal. 
     
     
         65 . The method of claim  1  wherein the fluid injected in the third phase has a lower viscosity than the fluid injected in the second phase. 
     
     
         66 . The method of claim  1  wherein the fluid injected in the third phase has a viscosity that is approximately equal to the viscosity of a physiological saline solution or of blood plasma. 
     
     
         67 . The method of claim  1  wherein the fluid in the first phase and the fluid in the third phase are delivered from a first source and the fluid in the second phase is delivered from a second source. 
     
     
         68 . The method of claim  1  wherein contrast agent in the first phase is of a different composition than the composition of contrast agent of the second phase or of the composition of contrast agent of the third phase. 
     
     
         69 . The method of claim  1  wherein contrast agent in the third phase is of a different composition than contrast agent of the second phase or of a different composition than contrast agent of the first phase. 
     
     
         70 . The method of claim  1 , wherein a first source of a diluent fluid is provided and a second source of a second fluid having a concentration of contrast agent is provided, the fluid in the first phase being formed by mixing the diluent fluid and the second fluid and the fluid in the third phase being formed by mixing the diluent fluid and the second fluid.