1. A method of treating an occluded blood vessel, the method comprising:
sensing the impedance at a plurality of locations around the circumference of the blood vessel at least two different frequencies to identify vascular occlusive material, and distinguish vascular occlusive material from the vessel wall.
2. The method of claim 1 further comprising applying ablative energy to the identified vascular occlusive material.
3. The method of claim 2 further comprising moving an electrode toward a location where vascular occlusive material has been identified, and applying ablative energy to the vascular occlusive material at the location.
4. The method of claim 1 wherein sensing the impedance at least two frequencies is done simultaneously.
5. The method of claim 1 wherein sensing the impedance at least two frequencies is done contemporaneously.
6. The method of claim 1 wherein sensing the impedance at least two frequencies is done within 10 ms.
7. The method of claim 1 wherein the impedance is sensed between two electrodes disposed in the blood vessel.
8. The method of claim 1 wherein the impedance is sensed between an electrode in the blood vessel and an electrode outside of the blood vessel.
9. The method of claim 1 wherein the two frequencies are sufficiently different to yield different impedance measurements for the living tissue of the vessel.
10. The method of claim 9 wherein the two frequencies include about 10 kHz and 100 kHz.
11. A method of treating an occluded blood vessel, the method comprising:
positioning a medical device in the blood vessel, the medical device having a plurality of electrodes around its circumference; and
sensing the impedance at a plurality of locations around the circumference of the blood vessel with the plurality of electrodes at least two different frequencies to identify vascular occlusive material, and distinguish vascular occlusive material from the vessel wall.
12. The method of claim 11 further comprising applying ablative energy to the identified vascular occlusive material.
13. The method of claim 11 further comprising using at least one of the electrodes on the medical device to apply ablative energy to the identified vascular occlusive material.
14. The method of claim 11 wherein sensing the impedance at least two frequencies is done simultaneously.
15. The method of claim 11 wherein sensing the impedance at least two frequencies is done contemporaneously.
16. The method of claim 11 wherein sensing the impedance at least two frequencies is done within 10 ms.
17. The method of claim 11 wherein the impedance is sensed between two electrodes disposed in the blood vessel.
18. The method of claim 17 wherein the two electrodes are disposed on the same medical device.
19. The method of claim 17 wherein the two electrodes are disposed on different medical devices.
20. The method of claim 11 wherein the impedance is sensed between an electrode in the blood vessel and an electrode outside of the blood vessel.
21. The method of claim 11 wherein the two frequencies are sufficiently different to yield different impedance measurements for the living tissue of the vessel.
22. The method of claim 11 wherein the two frequencies include about 10 kHz and 100 kHz.
23. A method of identifying vascular occlusive material in a vessel, comprising rotating and axially moving a electrode device through the vessel and measuring the impedance at points along the length of the device at least two frequencies, to distinguish between vascular occlusive material and vessel wall.
24. The method of claim 23 further comprising making a three dimensional map of the location of vascular occlusive material based upon the impedance measurements.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A seal assembly for insertion between two relatively rotatable members between which a wash fluid is present, and comprising a first rigid shield having an annular sealing member of an elastomeric material, and a second rigid shield mounted facing the first rigid shield and having respective sliding surfaces for a first and a second annular sealing lip of the annular sealing member; wherein the rigid shields have an L-shaped radial section, and the first and second annular sealing lips project from a flange portion of the first rigid shield towards a flange portion and a sleeve portion, respectively, of the second rigid shield to exert axial sealing pressure and radial sealing pressure, respectively, on said sliding surfaces; and
wherein the first annular sealing lip has a radial seat facing the opposite way to the second annular sealing lip and housing a toroidal spring, which exerts a radial thrust on the first annular sealing lip eccentrically with respect to an elastic hinge defined by a root portion common to the first and second annular sealing lips, and having a center of rotation located along a first line extending through a V-shaped sealing edge of the first annular sealing lip and forming a 20\xb0 to 60\xb0 angle with a radial plane; wherein said first and said second annular sealing lips extend obliquely with respect to said sliding surfaces from said common root portion, and in opposite directions substantially along a second line parallel to said first line extending through the sealing edge of the first annular sealing lip; wherein said root portion is defined between a first and a second annular recess of the annular sealing member, which are opposite each other, have a U-shaped cross-section, and are defined by respective rounded bottom walls having their convexities facing each other, and which are substantially aligned along said first line.
2. The seal assembly as claimed in claim 1, wherein said second annular sealing lip has a V-shaped sealing edge perpendicular to the V-shaped sealing edge of the first annular sealing lip and defined by a radially inner, undulated, circumferential groove.
3. The seal assembly as claimed in claim 2, wherein said second annular sealing lip cooperates with said respective sliding surface of the second rigid shield with an interference fit; said undulated groove defining the V-shaped sealing edge of the second annular sealing lip, being designed to produce a hydrodynamic effect which reduces friction of the sealing edge on the sliding surface.
4. The seal assembly as claimed in claim 1, wherein said annular sealing member extends along the flange portion of the first rigid shield, and covers a sleeve portion of the first rigid shield to define a static sealing member radially outwards on the sleeve portion of the first rigid shield.
5. The seal assembly as claimed in claim 1, wherein said first and said second annular recesses are substantially perpendicular to each other at their respective bottom walls; the first annular recess being substantially perpendicular to an axis of symmetry of the annular sealing member, and the second annular recess being substantially parallel to said axis of symmetry.
6. A method comprising the steps of:
inserting a seal assembly as claimed in claim 1 between two relatively rotatable members between which a wash fluid is present;
mounting said first annular sealing lip to face an environment occupied by a wash fluid which comes into contact with said first annular sealing lip on the side facing said radial seat of the toroidal spring, and with said first annular recess; and
mounting said second annular sealing lip to face a rolling bearing of a drive shaft of a drum, so as to contact lubricating grease at least on the side facing said second annular recess.
7. The method as claimed in claim 6, further comprising:
mounting said second annular sealing lip to contact a respective sliding surface of the second rigid shield with an interference; and
producing, by means of an undulated groove defining a V-shaped sealing edge of the second annular sealing lip, a hydrodynamic effect which reduces friction of the sealing edge on the sliding surface.