Coregistration of endoluminal data points with values of a luminal-flow-related index
Apparatus and methods are described for use with an endoluminal data-acquisition device configured to be moved through a lumen of a subject's body, and a two-dimensional angiographic image of the lumen. A value of a luminal-flow-related index of the subject is determined non-invasively at a plurality of locations along the lumen, at least partially by performing image processing on the angiographic image. While the endoluminal data-acquisition device is being moved through the lumen, a set of endoluminal data points of the lumen at a plurality of locations within the lumen is acquired, using the endoluminal data-acquisition device. It is determined that respective endoluminal data points correspond to respective locations along the lumen, and, in response thereto, it is determined that respective endoluminal data points correspond to respective values of the luminal flow-related index. Other applications are also described.
1. A system, comprising:
a processor in communication with an extraluminal imaging device and an endoluminal data-acquisition device, wherein the extraluminal imaging device is configured to acquire at least one two-dimensional x-ray angiographic image of a blood vessel, wherein the endoluminal data-acquisition device is configured to be moved through the blood vessel and to obtain endoluminal data points of the blood vessel, and wherein the processor is configured to:
determine, using a single imaging modality, first values of a diameter of the blood vessel at a first plurality of locations along the blood vessel by performing image processing on the at least one two-dimensional x-ray angiographic image, wherein the single imaging modality comprises x-ray angiography;
determine, using the single imaging modality, a flow-related parameter of the blood vessel based on the determined values of the diameter of the blood vessel, wherein the flow-related parameter comprises at least one of blood velocity or blood pressure;
determine one or more values of a pressure ratio of the blood vessel at the first plurality of locations along the blood vessel based on the determined flow-related parameter;
determine, from the endoluminal data points, second values of the diameter of the blood vessel at a second plurality of locations within the blood vessel at which the endoluminal data points were obtained;
determine that one or more endoluminal data points correspond to respective locations of the first plurality of locations of the blood vessel by correlating the second values of the diameter of the blood vessel determined from the endoluminal data points with the first values of the diameter determined using image processing on the at least one two-dimensional x-ray angiographic image;
based on the determined correspondence of the one or more endoluminal data points to the respective locations along the blood vessel, co-register the one or more endoluminal data points to the one or more values of the pressure ratio; and
generate, on a display in communication with the processor, an output indicating the determined one or more values of the pressure ratio and the co-registered one or more endoluminal data points.
2. The system of claim 1 , wherein the one or more values of the pressure ratio comprises one or more values of a fractional flow reserve of the blood vessel at the first plurality of locations along the blood vessel.
3. The system of claim 1 , wherein the one or more values of the pressure ratio comprises one or more values of an instantaneous wave-free ratio of the blood vessel at the first plurality of locations along the blood vessel.
4. The system of claim 1 , wherein the processor is configured to generate the output by generating an output indicating that the one or more endoluminal data points correspond to the one or more values of the pressure ratio.
5. The system of claim 4 , wherein the endoluminal data-acquisition device is configured to obtain a set of endoluminal images, and wherein the processor is configured to generate the output by generating an output indicating that a given endoluminal image corresponds to a given value of the pressure ratio.
6. The system of claim 4 , wherein the endoluminal data-acquisition device is configured to obtain a set of endoluminal functional data points, and wherein the processor is configured to generate the output by generating an output indicating that a given endoluminal functional data point corresponds to a given value of the pressure ratio.
7. The system according to claim 1 , wherein the processor is configured to:
determine a second flow-related parameter by performing image processing on the at least one two-dimensional x-ray angiographic image to derive third values of the diameter of the blood vessel at the first plurality of locations along the blood vessel at a time when the blood vessel was healthy; and
determine the one or more values of the pressure ratio based on a relationship between the flow-related parameter and the second flow-related parameter,
wherein the processor is configured to determine that respective endoluminal data points correspond to the respective locations along the blood vessel by correlating the second values of the diameter derived from the endoluminal data points with the first values of the diameter derived from the at least one two-dimensional x-ray angiographic image at the time when the blood vessel is stenosed.
8. The system according to claim 1 , wherein the processor is configured to:
determine a second flow-related parameter by performing image processing on the at least one two-dimensional x-ray angiographic image to derive third values of the diameter of the blood vessel at a proximal location of the blood vessel different from the first plurality of locations along the blood vessel; and
determine the one or more values of the pressure ratio based on a relationship between the flow-related parameter and the second flow-related parameter.
9. A method for evaluating blood flow, comprising:
obtaining, by an extraluminal imaging device, at least one two-dimensional x-ray angiographic image of a blood vessel;
determining, by a processor in communication with the extraluminal imaging device and using a single imaging modality, first values of a diameter of the blood vessel at a first plurality of locations along the blood vessel by performing image processing on the at least one two-dimensional x-ray angiographic image, wherein the single imaging modality comprises x-ray angiography;
determining, by the processor and using the single imaging modality, a flow-related parameter of the blood vessel based on the determined first values of the diameter of the blood vessel, wherein the flow-related parameter comprises at least one of blood velocity or blood pressure;
determining, by the processor, one or more values of a pressure ratio of the blood vessel at the first plurality of locations along the blood vessel based on the determined flow-related parameter;
obtaining, by an endoluminal data-acquisition device in communication with the processor, endoluminal data points of the blood vessel at a second plurality of locations within the blood vessel while being moved through the blood vessel,
determining, from the endoluminal data points, second values of a diameter of the blood vessel at the second plurality of locations within the blood vessel at which the endoluminal data points were acquired;
determining that one or more endoluminal data points correspond to respective locations of the first plurality of locations along the blood vessel by correlating the second values of the diameter determined from the endoluminal data points with the first values of the diameter determined using image processing on the at least one two-dimensional x-ray angiographic image;
based on the determined correspondence of the one or more endoluminal data points to the respective locations along the blood vessel, co-registering the one or more endoluminal data points to the one or more values of the pressure ratio; and
generating, on a display in communication with the processor, an output indicating the determined one or more values of the pressure ratio and the co-registered one or more endoluminal data points.
10. The method of claim 9 , wherein the one or more values of the pressure ratio comprises one or more values of a fractional flow reserve of the blood vessel at the first plurality of locations along the blood vessel.
11. The method of claim 9 , wherein the one or more values of the pressure ratio comprises one or more values of an instantaneous wave-free ratio of the blood vessel at the first plurality of locations along the blood vessel.
12. The method of claim 9 , wherein obtaining the endoluminal data points of the blood vessel comprises obtaining a set of endoluminal images, and wherein generating the output comprises generating an output indicating that a given endoluminal image corresponds to a given value of the pressure ratio.
13. The method of claim 9 , wherein acquiring the endoluminal data points of the blood vessel comprises obtaining a set of endoluminal functional data points, and wherein generating the output comprises generating an output indicating that a given endoluminal functional data point corresponds to a given value of the pressure ratio.