1. A method for determining a displacement map between first and second data frames containing RF data values comprising:
indexing the RF data values for the first and second frames with a sample resolution and a display resolution;
creating at least one axial reference line of RF data values having a plurality of positions indexed at the display resolution in the first RF frame;
using a block-matching algorithm with reference blocks centered on the axial reference line positions, determining the best axial displacement estimations for the axial reference line positions in the second RF frame;
storing the axial displacement estimation values for each axial reference line position; and
defining an axial reference line position as a transition point, wherein when adjacent axial reference line positions have different values, the axial reference line position having the greater value is a transition point.
2. The method according to claim 1 wherein display resolution is a multiple of sampling resolution.
3. The method according to claim 2 wherein a displacement estimation is obtained using a block-matching algorithm between a reference block located in the first RF data frame and a plurality of candidate blocks located in the second RF data frame.
4. The method according to claim 3 further comprising:
performing a displacement estimation at a lateral location adjacent to a transition point;
performing lateral tracking comprising:
if the displacement estimation for the adjacent lateral location equals the transition point value, performing additional displacement estimations for adjacent axial locations until a displacement estimation for an adjacent axial location is less than the transition point value;
if the displacement estimation for the adjacent axial location is greater than the transition point value, performing additional displacement estimations for adjacent axial locations until a displacement estimation for an adjacent axial location is less than the transition point value;
if the displacement estimation for the adjacent axial location is less than the transition point value, performing additional displacement estimations for adjacent opposite axial locations until a displacement estimation for an adjacent axial location is the same as the transition point value;
determining the axial location displacement estimation value that is the same as the transition point value prior to the axial location that is less than the transition point value is a trajectory point;
using the determined trajectory point, repeating lateral tracking to determine a next trajectory point until there are no more lateral locations to consider; and
assembling a displacement map corresponding to a transition point from the plurality of corresponding trajectory points.
5. The method according to claim 4 further comprising, proceeding to a next higher indexed transition point.
6. The method according to claim 5 further comprising for each transition point, assembling a corresponding displacement map.
7. The method according to claim 6 further comprising assembling one displacement map from all transition point displacement maps.
8. The method according to claim 7 wherein areas on the one displacement map between two transition point maps are assigned the transition point value of the transition point having the lesser value.
9. A system for determining a displacement map between first and second data frames containing RF data values comprising:
means for indexing the RF data values for the first and second frames with a sample resolution and a display resolution;
means for creating at least one axial reference line of RF data values having a plurality of positions indexed at the display resolution in the first RF frame;
using a block-matching algorithm with reference blocks centered on the axial reference line positions, means for determining the best axial displacement estimations for the axial reference line positions in the second RF frame;
means for storing the axial displacement estimation values for each axial reference line position; and
means for defining an axial reference line position as a transition point, wherein when adjacent axial reference line positions have different values, the axial reference line position having the greater value is a transition point.
10. The system according to claim 9 wherein display resolution is a multiple of sampling resolution.
11. The system according to claim 10 wherein a displacement estimation is obtained using a block-matching algorithm between a reference block located in the first RF data frame and a plurality of candidate blocks located in the second RF data frame.
12. The system according to claim 11 further comprising:
means for performing a displacement estimation at a lateral location adjacent to a transition point;
means for performing lateral tracking comprising:
if the displacement estimation for the adjacent lateral location equals the transition point value, means for performing additional displacement estimations for adjacent axial locations until a displacement estimation for an adjacent axial location is less than the transition point value;
if the displacement estimation for the adjacent axial location is greater than the transition point value, means for performing additional displacement estimations for adjacent axial locations until a displacement estimation for an adjacent axial location is less than the transition point value;
if the displacement estimation for the adjacent axial location is less than the transition point value, means for performing additional displacement estimations for adjacent opposite axial locations until a displacement estimation for an adjacent axial location is the same as the transition point value;
means for determining the axial location displacement estimation value that is the same as the transition point value prior to the axial location that is less than the transition point value is a trajectory point;
using the determined trajectory point, means for repeating lateral tracking to determine a next trajectory point until there are no more lateral locations to consider; and
means for assembling a displacement map corresponding to a transition point from the plurality of corresponding trajectory points.
13. The system according to claim 12 further comprising, means for proceeding to a next higher indexed transition point.
14. The system according to claim 13 further comprising for each transition point, means for assembling a corresponding displacement map.
15. The system according to claim 14 further comprising means for assembling one displacement map from all transition point displacement maps.
16. The system according to claim 15 wherein areas on the one displacement map between two transition point maps are assigned the transition point value of the transition point having the lesser value.
17. A method for performing elasticity imaging between first and second data frames comprising:
estimating displacements between the first and second data frames for positions along at least one axial reference line in a region of interest in the first data frame;
defining transition points for positions on the at least one axial reference line;
tracking the transition points laterally through the region of interest;
assembling displacement maps from trajectories for each transition point;
assembling one displacement map from all transition point displacement maps; and
between transition point displacement maps, assigning the area a value belonging to the transition point having the lesser value.
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 medical device system, comprising:
an implantable medical device having a fixation member operatively coupled to said housing having an engaged state configured to engage tissue of a patient, said medical device being magnetically attractable;
a catheter having a lumen and a distal portion configured for insertion in a proximity of said implantable medical device; and
a magnetic element being configured to pass through said lumen of said catheter and to magnetically engage said implantable medical device when inserted toward said distal portion of said catheter.
2. The medical device system as in claim 1 wherein a magnetic attraction between said magnetic element and said implantable medical device is sufficient to extract said implantable medical device as said magnetic element is extracted.
3. The medical device system as in claim 2 wherein said magnetic attraction between said magnetic element and said implantable medical device is at least four Newtons.
4. The medical device system as in claim 2 wherein said fixation member is at least one tine having a fixation force securing said at least one tine to said tissue of said patient and wherein said magnetic attraction between said magnetic element and said implantable medical device is greater than said fixation force.
5. The medical device system as in claim 1 wherein said fixation member has an engaged state engaged with said tissue of said patient while implanted and an unengaged state unengaged with said tissue of said patient and wherein said fixation member changes from said engaged state to said unengaged state by operation of said magnetic element.
6. The medical device system as in claim 1 wherein said fixation member is located proximate a distal portion of said implantable medical device.
7. The medical device system as in claim 6 wherein a proximal portion of said implantable medical device is magnetically attractable to said magnetic element.
8. The medical device system as in claim 1 further comprising a snare having a distal portion and configured for insertion, said snare having a mechanical engaging member proximate said distal portion of said snare, said snare being configured to pass through said catheter and mechanically engage said implantable medical device.
9. The medical device system as in claim 8 wherein said snare is configured to pass through said catheter and mechanically engage said implantable medical device while said magnetic element has magnetically engaged said implantable medical device.
10. The medical device system as in claim 9 wherein, when said magnetic element is magnetically engaged with said implantable medical device, said magnetic element provides, at least in part, a physical guide for said snare to mechanically engage said implantable medical device.
11. The medical device system as in claim 8 wherein said fixation member comprises at least one tine having a fixation force securing said at least one tine to said tissue of said patient and wherein said mechanical engaging member mechanically engages said implantable medical device proximate said second portion of said implantable medical device with a connection force greater than said fixation force of said at least one tine.
12. The medical device system as in claim 8 wherein said mechanical engaging member comprises a lasso.
13. The medical device system as in claim 1 wherein said fixation member is located proximate a first end of said implantable medical device and wherein said implantable medical device further comprises a magnetic component positioned proximate a second end of said implantable medical device opposite said first end providing said magnetic attraction.
14. The medical device system of claim 13 wherein said magnetic component of said implantable medical device comprises a magnet.
15. The medical device system of claim 1 wherein said catheter and said magnetic element are configured to be inserted transvenously.
16. A medical device extraction system for a implantable medical device having a fixation member operatively coupled to said housing having an engaged state configured to engage tissue of a patient, said medical device being magnetically attractable, comprising:
a catheter having a lumen and a distal portion configured for insertion in a proximity of said implantable medical device; and
a magnetic element being configured to pass through said lumen of said catheter and to magnetically engage said implantable medical device when inserted toward said distal portion of said catheter.
17. The medical device extraction system of claim 16 wherein said medical device extraction system is configured to disengage said fixation member of said implantable medical device from said tissue of said patient and extract said implantable medical device from said patient.
18. The medical device system as in claim 16 wherein said snare is configured to pass through said catheter and mechanically engage said implantable medical device while said magnetic element has magnetically engaged said implantable medical device.
19. The medical device extraction system as in claim 16 wherein a magnetic attraction between said magnetic element and said implantable medical device is sufficient to extract said implantable medical device as said magnetic element is extracted.
20. The medical device extraction system as in claim 19 wherein said magnetic attraction between said magnetic element and said implantable medical device is at least four Newtons.
21. The medical device extraction system as in claim 19 wherein said fixation member is at least one tine having a fixation force securing said at least one tine to said tissue of said patient and wherein said magnetic attraction between said magnetic element and said implantable medical device is greater than said fixation force.
22. The medical device extraction system as in claim 16 wherein said fixation member has an engaged state engaged with said tissue of said patient while implanted and an unengaged state unengaged with said tissue of said patient and wherein said fixation member changes from said engaged state to said unengaged state by operation of said magnetic element.
23. The medical device extraction system as in claim 16 wherein said fixation member is located proximate a distal portion of said implantable medical device.
24. The medical device extraction system as in claim 23 wherein a proximal portion of said implantable medical device is magnetically attractable to said magnetic element.
25. The medical device extraction system as in claim 16 further comprising a snare having a distal portion and configured for insertion, said snare having a mechanical engaging member proximate said distal portion of said snare, said snare being configured to pass through said catheter and mechanically engage said implantable medical device.
26. The medical device system as in claim 25 wherein said snare is configured to pass through said catheter and mechanically engage said implantable medical device while said magnetic element has magnetically engaged said implantable medical device.
27. The medical device system as in claim 26 wherein, when said magnetic element is magnetically engaged with said implantable medical device, said magnetic element provides, at least in part, a physical guide for said snare to mechanically engage said implantable medical device.
28. The medical device extraction system as in claim 25 wherein said fixation member comprises at least one tine having a fixation force and wherein said mechanical engaging member mechanically engages said implantable medical device proximate said second portion of said implantable medical device with a connection force greater than said fixation force of said at least one tine.
29. The medical device system as in claim 25 wherein said mechanical engaging member comprises a lasso.
30. The medical device extraction system as in claim 16 wherein said fixation member is located proximate a first end of said implantable medical device and wherein said implantable medical device further comprises a magnetic component positioned proximate a second end of said implantable medical device opposite said first end providing said magnetic attraction.
31. The medical device extraction system of claim 30 wherein said magnetic component of said implantable medical device comprises a magnet.
32. The medical device extraction system of claim 16 wherein said catheter and said magnetic element are configured to be inserted transvenously.
33. A method of extracting a magnetically attractable implantable medical device having a fixation member operatively coupled to said housing having an engaged state configured to engage tissue of a patient, comprising the steps of:
inserting a catheter having a lumen and a distal portion in proximity of said implantable medical device; and
inserting a magnetic element through said lumen of said catheter;
magnetically engaging said implantable medical device when said magnetic element is inserted toward said distal portion of said catheter; and
removing said implantable medical device by extracting said magnetic element.
34. The method as in claim 33 further comprising the step, after said magnetically engaging step, of disengaging said fixation member of said implantable medical device from said tissue of said patient.
35. The method as in claim 34 wherein said removing step is accomplished with said magnetic attraction between said magnetic element and said implantable medical device being sufficient to hold said implantable medical device as said magnetic element is extracted.
36. The method as in claim 35 wherein said magnetic attraction between said magnetic element and said implantable medical device is at least four Newtons.
37. The method as in claim 35 wherein said fixation member is at least one tine having a fixation force securing said at least one tine to said tissue of said patient and wherein said magnetic attraction between said magnetic element and said implantable medical device is greater than said fixation force.
38. The method as in claim 33 wherein said fixation member has an engaged state engaged with said tissue of said patient while implanted and an unengaged state unengaged with said tissue of said patient and further comprising the step of changing said fixation member from said engaged state to said unengaged state by operation of said magnetic element.
39. The method as in claim 33 wherein said fixation member is located proximate a distal portion of said implantable medical device.
40. The method as in claim 39 wherein a proximal portion of said implantable medical device is magnetically attractable to said magnetic element.
41. The method as in claim 33 further comprising the step, after said magnetically engaging step, of second mechanically engaging said implantable medical device with a snare inserted through said lumen of said catheter.
42. The method as in claim 41 wherein second mechanically engaging step when said magnetic element is magnetically engaged with said implantable medical device, said magnetic element provides, at least in part, a physical guide for said snare to mechanically engage said implantable medical device
43. The method as in claim 41 wherein said fixation member comprises at least one tine having a fixation force and implantable medical device is mechanically engaged proximate said second portion of said implantable medical device with a connection force greater than said fixation force of said at least one tine.
44. The medical device system as in claim 41 wherein said second mechanically engaging step comprises engaging said implantable medical device with a lasso.
45. The method as in claim 33 wherein said fixation member is located proximate a first end of said implantable medical device and wherein said implantable medical device further comprises a magnetic component positioned proximate a second end of said implantable medical device opposite said first end providing said magnetic attraction.
46. The method of claim 45 wherein said magnetic component of said implantable medical device comprises a magnet.
47. The method of claim 33 wherein said inserting a catheter step, said inserting a magnetic element step and said removing step are transvenous.