Apparatus, system and method for the detection and quantification of conductance of right-to-left cardiac shunts

A method for estimating a total number of microbubbles contained within a known volume of contrast agent being injected into a vein of a patient to quantify a conductance of a right-to-left cardiac shunt after adjusting a number of detected embolic tracks, NET, based on the total number of microbubbles contained within the injected contrast agent the method comprising the steps of:

• a. preparing microbubble containing contrast agent (45) by repeatedly and cyclically exchanging a mixture of saline, air and blood between a first syringe (47) and a second syringe (41) wherein initially the first syringe containing the saline/air/blood mixture is fully and rapidly expelled by an operator into the empty second syringe and then the process is immediately reversed and the saline/air/blood mixture is rapidly expelled back into the first syringe representing one complete agitation cycle, this agitation cycle being repeated for at least six complete cycles to affect the agitation required to create the total number of microbubbles;
• b. positioning an optically transparent microbubble counting cell (44) external to the patient along a pathway between the contrast agent containing first syringe and a venous access needle (48) placed in the vein of the patient;
• c. attaching an image sensor (130) having a field of view to the optically transparent microbubble counting cell, the image sensor communicating with a controller;
• d. injecting the contrast agent into an interior chamber of the optically transparent microbubble counting cell located between the contrast agent containing first syringe and the venous access needle;
• e. imaging the microbubbles within a predefined microbubble counting zone (146) occupying a known volume within the microbubble counting cell (44) as seen in the field of view of the image sensor attached to the microbubble counting cell (44) to capture an image of a layer of injected contrast agent within the microbubble counting zone (146) within the microbubble counting cell (44) as the contrast agent is injected through the venous access needle (48) and into the patient;
• f. counting a number of microbubbles within the microbubble counting zone of the microbubble counting cell, NCOUNT, by an automated image analysis in the controller of a recorded image of microbubbles within microbubble counting zone (146) acquired by the image sensor (130);
• and
• g. estimating the total number of microbubbles within the known volume of injected contrast agent, NBUBBLES, injected through the venous access needle (48) and into the vein (5) of the patient by multiplying the number of microbubbles counted within the microbubble counting zone in step in [f], NCOUNT, by the ratio of the known volume of the injected contrast agent (45) injected into the vein of the patient divided to the known volume of the microbubble counting zone (146).