Last month, European medical regulators recommended that anybody who needed an MRI scan should be given a check to ensure their kidneys are healthy if they were to be given General Electric’s Omniscan or two similar contrast agents. And the FDA is conducting its own review.

But Henrik Thomsen isn’t talking about it, even though he heads the department of diagnostic sciences at the University of Copenhagen and is part of a small group of clinicians credited with alerting patients and regulators to the potential risks of Omniscan for renal patients. Why? A talk he gave last year prompted GE Healthcare to sue him for libel, The Times of London writes.

GE has already racked up costs of more than $600,000 pursuing Thomsen, who has authored or co-authored nearly 400 papers and will have to pay GE’s costs if he loses. Campaign groups have warned that vital scientific and medical work is being threatened because of the danger of libel actions. “I believe the lawsuit is an attempt to silence me,” he tells the paper. “It’s dangerous for the patient if we can’t frankly exchange views.”

GE Healthcare appears to have reacted promptly to concerns, the Times writes, but objects to some of Thomsen’s work and decisions by European regulators. GE doesn’t deny an association between Omniscan and Nephrogenic Systemic Fibrosis, but insists a causal link has “not been established,” and that a reporting bias may account for the high number of NSF cases linked to its product.

In the US, docs have been warned of an association. And earlier this month, the FDA said it now believes that Omniscan, Optimark and Magnevist pose higher risks. An FDA advisory panel went further and recommended that Omniscan and Optimark should not be given to patients with severe kidney disease (see here).