Legal wrangling puts rights to diffusion tensor imaging in spotlight

November 5, 2010
Greg Freiherr

A California neurosurgeon has launched what could turn into an epic legal battle over the rights to use diffusion tensor imaging, an MR technology that lately has begun to catch on as a diagnostic and neurosurgical planning tool.

A California neurosurgeon has launched what could turn into an epic legal battle over the rights to use diffusion tensor imaging, an MR technology that lately has begun to catch on as a diagnostic and neurosurgical planning tool.

Claiming that he holds the exclusive license to this technology, and that all users are violating that license, Dr. Aaron Filler has filed suit against the Regents of the University of California and Siemens Healthcare.

If successful, the two suits could set precedents, allowing Filler and his company, NeuroGrafix, to sue any university in any state in the union and any vendor whose products involve diffusion tensor imaging (DTI).

And Filler’s argument is not just with vendors and universities. Anyone using diffusion tensor imaging or neurography is infringing the patent, Filler contends.

“They should arrange for a license or a lease arrangement,” he said.

The rights associated with the patent, US patent 5,560,360, specifically address MR neurography. But Filler claims other techniques that visualize neural tracts in the brain or muscle fibers in the heart, particularly DTI, are covered.

Filler may be over-reaching, if claims made by Dr. Peter Basser are correct. Basser says he and two other scientists invented diffusion tensor imaging. Their patent, issued July 23, 1996, describes a method for “measuring the effective diffusion tensor for spin labeled particles and generating images therefrom.” More than two years before the patent was issued, Basser and colleagues mentioned in the patent, James Mattiello and Denis LeBihan, wrote a paper entitled “MR Diffusion Tensor Spectroscopy and Imaging.” Published in January 1994, the article describes “a new NMR imaging modality – MR diffusion tensor imaging.”

“Neurography and DTI are really different inventions,” said Basser, Ph.D., a senior investigator and director of the Program on Pediatric Imaging and Tissue Sciences at the National Institute of Child Health and Human Development. “As far as I can tell, neurography is just a technique that (Filler) and his colleagues developed to make nerves more visible. DTI involves a way of reporting information contained in the diffusion tensor, defining quantities and intrinsic properties of tissue that is very useful in making (neural) maps.”

Setting aside the dispute over the DTI patent, there are questions about Filler’s right to litigate his latest lawsuit. The University of California – as part of the state of California – is legally protected under sovereign immunity, which allows states to seize property, if its seizure is for the public benefit.

To battle the UC Regents, Filler has come up with a novel twist on a legal argument called “Inverse Condemnation.” He contends that California has not employed due process nor has it provided fair compensation for the seizure of rights to the technology covered by the neurography patent. The outcome could have far flung repercussions.

The 50 states are immune from patent litigation, because they cannot be forced to appear in court to answer charges of infringement, according to Filler. But Inverse Condemnation should trump sovereign immunity, he said, clearing the way for litigation against any U.S. universities.

Filler has similar ambitions in regard to the radiology industry. If successful against Siemens, he expects other vendors will line up to pay for past and future use of DTI.

“Once a particular patent is proven, such as the MRI patent held by Dr. (Raymond) Damadian, once he battled it out with GE, he got settlements from the other entities,” he said.

Filler’s efforts are being fueled by a $900,000 out-of-court settlement from his former research colleague Dr. Jay Tsuruda and Oak Tree Medical Center in Pasadena, CA, for infringement of the neurography patent. Ironically, Tsuruda is on the patent with Filler as co-inventor. According to Filler, however, the two men signed their rights over to the University of Washington in Seattle, which later licensed the patent exclusively to Filler’s firm.

“I think that (the settlement) was very helpful, because it showed that this a viable patent,” Filler said. “I think they thought at first that this patent would not be valid, but as they got into it further they realized that it was not a case that they could win.”

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