Federal Circuit Affirms PTAB Decision Finding Unpatentable Challenged Claims Of Medical-Imaging Patent
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  • Federal Circuit Affirms PTAB Decision Finding Unpatentable Challenged Claims Of Medical-Imaging Patent


    On February 20, 2024, the U.S. Court of Appeals for the Federal Circuit (“CAFC”) issued an opinion affirming the decision of the Patent Trial and Appeal Board (“Board”) finding unpatentable the challenged claims of a medical-imaging patent directed to using a headset to view three-dimensional images of a patient. D3D Technologies, Inc. v. Microsoft Corp., __ F.4th __ (Fed. Cir. Feb. 20, 2024).

    U.S. Patent No. 9,349,183, owned by D3D Technologies, Inc. (“D3D”), discloses methods for using two-dimensional image slices captured by medical-imaging equipment (such as an MRI machine or a CT scanner) to generate images for a user’s right and left eyes. The images are displayed to the user’s individual eyes in a headset. Because each eye will see the image from a different angle, the brain interprets the left-eye viewing angle’s image and right-eye viewing angle’s image together to give depth perception, which creates the effect of a three-dimensional image.

    Microsoft petitioned for inter partes review of the ‘183 patent. The Board instituted the IPR and subsequently found all of the challenged claims unpatentable on several different grounds.

    On appeal, the CAFC addressed D3D’s arguments relating to the Board’s claim construction of the phrase “convergence point,” as well as the Board’s obviousness findings with respect to the combination of two prior art references, “Murphy” and “Guang.” In light of the CAFC’s findings with respect to these two issues, as discussed below, the CAFC declined to reach any of D3D’s other arguments on appeal.

    The “convergence point” limitation provides: “wherein a convergence point of said image for said left eye and said image for said right eye is shifted to provide a different perspective of the volume of interest to said user….”

    With respect to the claim construction of “convergence point,” the Board determined in relevant part that the limitation does not require a shifting of the convergence point to occur while holding left and right viewpoints unaltered. D3D disagreed with this finding because it believed that the viewpoints must remain unaltered.

    On appeal, the CAFC noted that the limitation is silent as to whether the left- and right-eye viewpoints remain the same after the convergence point has been shifted. And further, the CAFC explained that, although claim 1 earlier recites “selecting a viewpoint for a left eye,” “selecting a viewpoint for a right eye,” and “displaying” an image for the left and right eyes “based on said initial viewing angle, said view point … and said volume of interest,” nothing in this language requires or even suggests that the viewpoint thereafter remain unchanged once the convergence point is shifted. Given that lack of suggestion or requirement in the claims, and the fact that D3D did not point to any supporting language in the specification or persuasive expert testimony, the CAFC affirmed the Board’s construction and declined to read in the limitation that the viewpoints must remain unaltered.

    With respect to the Board’s determination that Murphy and Guang render obvious the challenged claims, D3D’s argument hinged in large part on its claim construction position that the viewpoints must remain unaltered. With that position in mind, D3D argued that the combination of Murphy and Guang would use new viewpoints for the left and right eye images, and therefore would not render the challenged claims unpatentable.

    On appeal, the CAFC agreed with the Board that Murphy allows surgeons to move their eyes to the part of the image they want to enhance, and that Guang teaches shifting the convergence point by describing dynamic adjustment of an eye convergence point for stereo display. The CAFC further agreed that the Board properly credited the testimony of Microsoft’s expert, Dr. Zyda, as consistent with these teachings. And the CAFC noted that, even under D3D’s construction, the Board remained persuaded that the prior art meets the claim requirements. Accordingly, the CAFC found the Board’s findings with respect to Murphy and Guang supported by substantial evidence and affirmed the finding of unpatentability.

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