Automated three dimensional aortic root measurement and modeling
An ultrasound system for planning a surgical implantation of a prosthetic aortic valve produces three dimensional images of the aortic root region of a patient. An electronic model of an aortic root is accessed and fitted to the aortic root in a three dimensional ultrasound image. Preferably the aortic root model exhibits closed contour cross-sections which are fitted to the endothelial lining of the aortic root in the ultrasound image. A medial axis of the fitted model is identified and radii measured from the medical axis to the border of the fitted model. The radii are joined to identify a surface forming a mesh model fitted to the aortic root anatomy of the patient. The shape and dimensions of the fitted model may be used to fabricate a custom prosthetic valve for aortic valve replacement.
1. An ultrasound system which is used to plan a surgical procedure with an implantable device in an aortic root, comprising:
an ultrasound probe adapted to scan a volumetric region including an aortic root;
an image generator coupled to the ultrasound probe and configured to produce a three dimensional ultrasonic image of the aortic root;
electronic circuitry comprising a 3D shape processor that is configured to:
receive the three dimensional ultrasonic image of the aortic root and a three dimensional anatomical model of the aortic root, electronically stored in memory on the ultrasound system;
fit closed contour cross-sections of the anatomical model to a shape of the aortic root in the three dimensional ultrasonic image to adjust a shape of the anatomical model to fit the aortic root in the three dimensional image;
produce a scaled model of the aortic root;
locate a medial axis of the scaled model by determining a center point of each closed contour cross-section of the scaled model, wherein the determining the center point comprises locating a plurality of circles or polygons around an interior of the closed contour cross-section and averaging the centers of the plurality of circles or polygons to yield the center point of each closed contour cross-section;
produce measurements of the closed contour cross-sections at a plurality of locations along the medial axis of the scaled model of the aortic root;
produce a histogram of the measurements; and
determine at least one peak of the histogram;
a display coupled to the image generator and the 3D shape processor and configured to display the three dimensional ultrasonic image of the aortic root; and
an output at which data corresponding to the measurements of closed contour cross-sections at the plurality of locations along the medial axis of the scaled model of the aortic root and the at least one peak is provided to produce a custom implantable device.
2. The ultrasound system of claim 1 , wherein the closed contour cross-sections of the scaled model are produced for key anatomical landmarks of the aortic root.
3. The ultrasound system of claim 2 , wherein the three dimensional anatomical model exhibits a plurality of elliptical cross-sections along the medial axis at locations corresponding to anatomical landmarks of an aortic root.
4. The ultrasound system of claim 3 , wherein the elliptical cross-sections corresponding to anatomical landmarks of the aortic root are fitted to an endothelial lining in the three dimensional ultrasonic image of the aortic root.
5. The ultrasound system of claim 4 , wherein the elliptical cross-sections are fitted to the endothelial lining by recognizing a gradient in the three dimensional ultrasonic image.
6. The ultrasound system of claim 1 , wherein the closed contour cross-sections of the scaled model are circles or ellipses or both, and the measurements are radial measurements.
7. The ultrasound system of claim 1 , wherein the 3D shape processor is further configured to make radial measurements from the medial axis to a border of the anatomical model.
8. The ultrasound system of claim 7 , wherein the 3D shape processor is further configured to identify a three dimensional surface of the anatomical model from the radial measurements.
9. The ultrasound system of claim 8 , wherein the three dimensional surface further comprises a mesh model of the aortic root of the three dimensional ultrasonic image.
10. The ultrasound system of claim 9 , wherein the mesh model is provided at the output to produce the custom implantable device.
11. The ultrasound system of claim 1 , wherein the three dimensional anatomical model is stored and the 3D shape processor is located on a workstation separate from the ultrasound probe and image generator.
12. The ultrasound system of claim 1 , wherein the custom implantable device is a prosthetic aortic valve replacement.
13. The ultrasound system of claim 1 , wherein the measurements of the closed contour cross-sections at a plurality of locations along the medial axis of the scaled model of the aortic root are found for different phases of a heart cycle.
14. The ultrasound system of claim 1 , wherein the display is further configured to display the histogram.
15. The ultrasound system of claim 1 , wherein the at least one peak of the histogram corresponds to a measurement at a location of a key anatomical landmark.