Devices, Systems and Methods for Determining Sizes of Vessels

1 . A device for determining a cross sectional size of a vessel, the device comprising:

an elongated body having a longitudinal axis extending from a proximal end to a distal end, the body having a lumen along the longitudinal axis and enabling introduction of the distal end into a lumen of a vessel;

a first excitation electrode and a second excitation electrode along the longitudinal axis, both located in respective grooves near the distal end; and

a first detection electrode and a second detection electrode located in respective grooves along the longitudinal axis and in between the first and second excitation electrodes;

wherein at least one of the first and second excitation electrodes is in communication with a current source, thereby enabling a supply of electrical current to the vessel, thereby enabling measurement of two or more conductance values in the blood vessel by the detection electrodes, and thereby enabling calculation of parallel tissue conductance in the vessel, whereby tissue conductance is the inverse of resistance to current flow, which depends on the cross sectional area of the blood vessel.

2 . The device of claim 1 , wherein the conductance measurement takes into account an offset created in measured conductance by the presence of a stent in the cross sectional area that is being measured.

3 . The device of claim 1 , further comprising:

a data acquisition and processing system that receives conductance data from the detection electrodes and determines the conductance of the lumen.

4 . The device of claim 1 , further comprising:

a suction/infusion port located near the distal end, wherein said suction/infusion port is in communication with said lumen, thereby enabling injection of two or more solutions into the lumen.

5 . The device of claim 4 , wherein the solution comprises an NaCl solution.

6 . The device of claim 4 , wherein the lumen is in communication with a source of a solution to be injected therethrough and through the suction/infusion port into the lumen.

7 . A device for determining a cross sectional area of a vessel, the device comprising:

an elongated body having a lumen therethrough along its longitudinal length;

a pair of excitation electrodes located in respective grooves on the elongated body; and

a pair of detection electrodes located in respective grooves located in between the pair of excitation electrodes such that a distance between one detection electrode and its adjacent excitation electrode is equal to the distance between the other detection electrode and its adjacent excitation electrode;

wherein at least one excitation electrode is in communication with a current source, thereby enabling a supply of electrical current to a lumen of a vessel, and enabling measurement of two or more conductance values at the lumen by the detection electrodes, resulting in an assessment of the cross sectional area of the blood vessel.

8 . A catheter for determining a cross sectional area of a vessel, the device comprising:

an elongated body having a lumen therethrough along its longitudinal length;

a pair of excitation electrodes located in respective grooves on the elongated body; and

a pair of detection electrodes located in respective grooves between the pair of excitation electrodes such that a distance between one detection electrode and its adjacent excitation electrode is equal to the distance between the other detection electrode and its adjacent excitation electrode;

wherein when two solutions of differing conductive concentrations are introduced to a lumen of a vessel through the lumen of the elongated body at different times, two conductance measurements are made by the detection electrodes, resulting in a calculation of parallel tissue conductance at the lumen to determine cross sectional area.

9 . The catheter of claim 8 , wherein the detection and excitation electrodes have insulated electrical wire connections that run through the lumen of the elongated body.

10 . The catheter of claim 8 , wherein the detection and excitation electrodes have electrical wire connections that are embedded within the elongated body such that each wire is insulated from the other wires.

11 . A catheter for determining a cross sectional area of a vessel, the device comprising:

an elongated body having a proximal end and a distal end and a lumen therethrough;

a second body that terminates at the elongated body at a point between the proximal end and the distal end, and having a lumen that joins the lumen of the elongated body;

a pair of excitation electrodes located in respective grooves at a distal end of the elongated body; and

a pair of detection electrodes located in respective grooves between the pair of excitation electrodes;

wherein when two solutions of differing conductive concentrations are introduced to a lumen of a blood vessel, located near the distal end of the elongated body, through the lumen of the second body, two conductance measurements are made by the detection electrodes, resulting in a calculation of parallel tissue conductance at the lumen to determine cross sectional area of the blood vessel.

12 . The catheter of claim 11 , wherein the detection and excitation electrodes have insulated electrical wire connections that run through the lumen and proximal end of the elongated body.

13 . The catheter of claim 11 , wherein the detection and excitation electrodes have electrical wire connections that are embedded within the elongated body such that each wire is insulated from the other wires.

14 . The catheter of claim 11 , further comprising a guide wire positioned through the proximal end of the elongated body, through the lumen of the elongated body and out of the distal end of the elongated body.

15 . A catheter system for determining a cross sectional area of a vessel as determined by resistance to flow of electrical currents through the lumen, the system comprising:

an elongate wire having a longitudinal axis with a proximal end and a distal end;

a catheter comprising an elongate tube extending from a proximal tube end to a distal tube end, the tube having a lumen and surrounding the wire coaxially;

a first excitation electrode and a second excitation electrode each located in respective grooves along the longitudinal axis of the wire near the distal wire end; and

a first detection electrode and a second detection electrode in respective grooves along the longitudinal axis of the wire and in between the first and second excitation electrodes,

wherein at least one of the first and second excitation electrodes is in communication with a current source, thereby enabling a supply of electrical current to a lumen of a vessel, thereby enabling measurement of two or more conductance values at the lumen by the detection electrodes, and thereby enabling calculation of tissue conductance at the lumen, whereby tissue conductance is the inverse of resistance to current flow, which depends on the cross sectional area of the vessel.

16 . The system of claim 15 , wherein the wire comprises a pressure wire.

17 . The system of claim 15 , wherein the wire comprises a guide wire.

18 . The system of claim 15 , wherein the catheter comprises a guide catheter.

19 . The system of claim 15 , wherein the wire and the catheter are dimensioned so that a first solution can be infused through the tube lumen.

20 . A system for measuring cross sectional area of a blood vessel, the system comprising:

a catheter assembly;

a solution delivery source for injecting a solution through the catheter assembly and into a plaque site;

a current source; and

a data acquisition and processing system that receives conductance data from the catheter assembly and determines a cross sectional area of a lumen of a vessel, whereby the conductance is the inverse of resistance to current flow, which depends on the cross sectional area of the blood vessel.

21 . The system of claim 20 , wherein the catheter assembly comprises:

an elongate wire having a longitudinal axis extending from a proximal wire end to a distal wire end;

a catheter comprising an elongate tube extending from a proximal tube end to a distal tube end, said tube having a lumen along its longitudinal axis, said tube surrounding the wire coaxially;

a first excitation impedance electrode and a second excitation impedance electrode each in respective grooves along the longitudinal axis of the wire, both located near the distal wire end; and

a first detection impedance electrode and a second detection impedance electrode each in respective grooves along the longitudinal axis of the wire, both located in between the first and second excitation electrodes.

22 . A method for determining a cross sectional area of a vessel, the method comprising:

introducing a catheter into a lumen of the vessel;

providing electrical current flow to the lumen through the catheter;

injecting a first solution of a first compound having a first concentration into the lumen;

measuring a first conductance value at the plaque site;

injecting a second solution of a second compound having a second concentration into the lumen, wherein the second concentration does not equal the first concentration;

measuring a second conductance value at the lumen; and

determining the cross sectional area of the vessel based on the first and second conductance values and the conductivity values of the first and second compounds.