Apparatus and methods for mapping a sequence of images to a roadmap image
Apparatus and methods are described including a processor ( 20 ) configured to receive first and second sets of extraluminal images of a lumen, the second set being acquired while an endoluminal device is being moved through the lumen. The processor designates at least one of the first set of images as a roadmap image, and designates, within the lumen in the roadmap image, a roadmap pathway ( 42 ). A plurality of features ( 44, 46, 48, 50 ) that are visible within at least some of the second set of extraluminal images are identified, and an arrangement of three or more of the features within the image are compared to a shape of at least a portion of the roadmap pathway. Based upon the comparing, the identified features are mapped to locations along the roadmap pathway within the roadmap image. Other applications are also described.
1. A method for mapping extraluminal images to a roadmap image, comprising:
obtaining, by one or more extraluminal imaging devices, a set of angiographic images of a vessel while contrast agent is present in the vessel;
designating, by a processor in communication with the one or more extraluminal imaging devices, at least one image from the set of angiographic images as a roadmap image;
generating, by the processor, a pathway in the roadmap image, the pathway representative of a shape of the vessel;
obtaining, by the one or more extraluminal imaging devices, a set of fluoroscopic images of the vessel;
identifying, by the processor, three or more features in each image of the set of fluoroscopic images, wherein the three or more features represent radiopaque portions of an endoluminal device positioned within the vessel;
determining an arrangement of the three or more features, wherein the arrangement of the three or more features is defined by a first vector corresponding to a first pair of the three or more features and a second vector corresponding to a different, second pair of the three or more features;
transforming the fluoroscopic images based on a comparison of the pathway and the arrangement of the three or more features, wherein transforming includes mapping, by the processor, the three or more features to corresponding locations on the pathway generated by the processor such that the arrangement of the three or more features is fit to the shape of the vessel; and
outputting, to a display in communication with the processor, a mapped set of images based on the mapping.
2. The method of claim 1 , further comprising:
classifying each of the three or more features as a feature type,
wherein transforming the fluoroscopic images comprises determining a transformation between the three or more features and the pathway, and
wherein an extent of the transformation is restricted based on the feature type.
3. The method of claim 2 , wherein determining the transformation comprises computing a minimized deformation of the three or more features.
4. The method of claim 3 , wherein computing the minimized deformation of the three or more features comprises using a relationship between locations of the three or more features and a plurality of corresponding locations along the pathway.
5. The method of claim 1 , further comprising obtaining, by a first endoluminal data-acquisition device, a first set of endoluminal data points at a plurality of locations in the vessel,
wherein obtaining the set of fluoroscopic images of the vessel comprises obtaining the set of fluoroscopic images while the vessel is undergoing changes in location and shape that vary in accordance with a cycle.
6. The method of claim 5 , further comprising:
determining a plurality of local calibration factors associated with portions of the roadmap image, wherein the local calibration factors are determined based on the mapping of the three or more features to the pathway;
co-registering the first set of endoluminal data points to respective locations within the roadmap image, by:
identifying a starting location of the first endoluminal data-acquisition device in the roadmap image; and
determining a distance from the starting location at which respective endoluminal data points were acquired, wherein the distance is determined based on:
a speed at which the first endoluminal data-acquisition device is moved through the vessel;
a frame rate at which the first set of endoluminal data points were acquired; and
the local calibration factors associated with the respective portion of the roadmap image.
7. The method of claim 6 , further comprising:
obtaining, by a second endoluminal data-acquisition device, a second set of endoluminal data points at a plurality of locations in the vessel; and
co-registering the second set of endoluminal data points to the first set of endoluminal data points by co-registering the second set of endoluminal data points to respective locations within the roadmap image.
8. The method of claim 5 , further comprising determining locations of the first endoluminal data-acquisition device in respective fluoroscopic images of the set of fluoroscopic images based on the mapping of the three or more features to the pathway.
9. The method of claim 8 , further comprising co-registering the first set of endoluminal data points to respective locations within the roadmap image.
10. The method of claim 5 , wherein the first endoluminal data-acquisition device comprises an endoluminal imaging device configured to acquire a plurality of endoluminal images while the endoluminal imaging device is moved through the vessel,
wherein the first set of endoluminal data points comprise the endoluminal images, and
wherein co-registering the first set of endoluminal data points to respective locations in the roadmap image comprises co-registering endoluminal images to the respective locations within the roadmap image.
11. The method of claim 5 , wherein the first endoluminal data-acquisition device is configured to acquire functional endoluminal data points of the vessel while the first endoluminal data-acquisition device is moved through the vessel, and
wherein co-registering respective endoluminal data points to respective locations in the roadmap image comprises co-registering the functional endoluminal data points to the respective locations within the roadmap image.
12. The method of claim 5 , wherein generating the output comprises generating a stack of endoluminal data points in which relative positions of the endoluminal data points within the stack correspond to relative locations of the endoluminal data points in the roadmap image.
13. The method of claim 12 , further comprising:
determining a parameter of a portion of the vessel that corresponds to a portion of the stack of endoluminal data points, wherein the parameter is determined based upon the co-registering of the endoluminal data points to the respective locations of the roadmap image; and
generating the output based on the determined parameter.
14. The method of claim 13 , further comprising:
receiving a user selection indicating a selected location in the stack of endoluminal data points,
wherein generating the output comprises generating an indication of a location on the roadmap image that corresponds to the selected location in the stack of endoluminal data points.
15. The method of claim 5 , further comprising:
receiving a user selection indicating a selected endoluminal data point,
wherein generating the output comprises generating an indication of a location on the roadmap image that corresponds to the selected endoluminal data point.
16. The method of claim 5 , further comprising:
receiving a user selection indicating a selected location on the roadmap image,
wherein generating the output comprises generating an indication of a location on the roadmap image that corresponds to the selected location.
17. The method of claim 1 , wherein the radiopaque portions of the endoluminal device comprise a first radiopaque marker disposed on the endoluminal device at a first location and a second radiopaque marker disposed on the endoluminal device at a second location distal of the first location.
18. The method of claim 1 , wherein the arrangement of the three or more features is further defined by an angle between the first vector the second vector.
19. The method of claim 1 , wherein the arrangement of the three or more features is further defined by a first distance corresponding to the first vector and a second distance corresponding to the second vector.
20. The method of claim 17 , wherein the endoluminal device comprises a stent or a balloon, wherein the first radiopaque marker is disposed on a proximal end of the stent or the balloon, and wherein the second radiopaque marker is disposed on a distal end of the stent or the balloon.
21. The method of claim 17 , wherein the first pair of the three or more features represents the first radiopaque marker and the second radiopaque marker.
22. The method of claim 1 , further comprising:
classifying a region of the pathway as corresponding to a first feature type; and
classifying a feature of the three or more features as corresponding to a different, second feature type,
wherein transforming the fluoroscopic images comprises determining a transformation between the three or more features and the pathway, and
wherein an extent of the transformation is restricted such that the feature of the three or more features is prevented from being mapped to the region of the pathway within the mapped set of images.
23. The method of claim 2 , further comprising:
determining a dimension associated with one or more of the three or more features based on the classifying,
wherein the extent of the transformation is restricted such that a mapped dimension associated with the one or more of the three or more features on the pathway within the mapped set of images is within a threshold of the dimension.
24. The method of claim 2 , wherein the extent of the transformation is restricted such that an order of appearance of the three or more features is maintained on the pathway within the mapped set of images.