NeuroGrafix accused Brainlab of infringing its U.S. Patent No. 5,560,360, which covers methods of imaging neural tissue to distinguish anisotropic nerve tracts in which water can diffuse along the length of the nerve tract but not perpendicularly to the nerve tract. A number of method claims were asserted, including a single independent claim. Brainlab sought summary judgment of non-infringement based in part on its chosen interpretation of two claim limitations – exposing a region that includes a selected structure that includes both anisotropic and non-anisotropic tissue to a magnetic polarizing field, and generating a data set that distinguishes the two structures. Brainlab contended that it cannot target the required “selected structure” because until the data is obtained, one cannot know where the anisotropic structure is, arguing that the ‘360 patent is directed to improved imaging of peripheral nerves, and that therefore the “select structure” must be limited to peripheral nerves, which Brainlab’s accused product does not track. Brainlab also asserted that its accused product does not distinguish anisotropic structure from non-anisotropic structure as required by the claims, because it does not permit the user to enter an FA Threshold value of zero, which would correspond to tissue that does not exhibit diffusion anisotropy. Judge Stearns determined that, while the motivation described for the invention was the improvement of peripheral nerve imaging, this motivation standing alone is insufficient to limit the scope of the claims. He cited language in the specification that referred to distinguishing anisotropic tissue from other structures that do not exhibit anisotrophy as referring to distinguishing tissue that had levels of anisotrophy low enough to be insignificant for imaging purposes as opposed to having an absolute absence of anisotrophy. He also criticized Brainlab’s attempt to draw limitations from dependent claims into the independent claim, the opposite of the principle of claim differentiation.
Despite ruling in NeuroGrafix’s favor on the disputed claim terms, Judge Stearns ultimately granted summary judgment of non-infringement to Brainlab. NeuroGrafix’s allegations were that Brainlab induces infringement, with the direct infringement occurring when the user images the pyramidal tract in the brain. Judge Stearns found that, depending on the purpose of the physician in imaging a patient, the accused product is capable of both infringing and non-infringing uses. Mere capability of infringement, however, is insufficient to establish liability, and NeuroGrafix could point to no record evidence that any physician had ever actually used the product in a manner that would infringe. Judge Stearns distinguished cases where direct infringement could be inferred by instructions that not only described the infringing mode, but taught or encouraged it; the marketing material for the accused product did note the possibility of delineating the pyramidal tract, but did not teach the particular settings to achieve this. Accordingly, Brainlab’s motion for summary judgment of non-infringement was allowed.