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Torsten Almén

The idea for a new x-ray contrast medium

”I don't remember what day it was,” says retired Professor of Radiology Torsten Almén in Malmö. ”But it was probably some time in 1964 that I got the idea. I was performing an angiography at the old radiology department at MAS (Malmö General Hospital, now Malmö University Hospital). I rinsed the catheter while it was inside the patient's artery in the groin. When I rinsed with 0.9% saline solution no pain was felt in the patient's leg, but when I injected the x-ray contrast medium it really hurt.”

Almén then recalled that saline solution was called ”physiologic” because 0.9 percent sodium chloride in water has the same osmotic pressure as extracellular fluid. Could it be so simple that the contrast medium caused pain because of its extremely high osmotic pressure? It was so concentrated that it had the consistency of syrup. Almén knew from personal experience swimming underwater that a high saline concentration could be irritating. On summer vacations, swimming off the west coast of Sweden in Bohuslän, he definitely experienced burning of the eyes. But the water didn't hurt at home, outside Ystad, where the water was brackish and not at all as salty as in Bohuslän.

In x-ray diagnostics, radiologists sometimes need contrast media. They contain iodine, which enables them to absorb the x-rays. Blood vessels by themselves are usually not at all visible in the x-ray picture, but when filled with contrast medium they appear clearly. Injecting contrast media has therefore become an important part of diagnosing vascular diseases such as atherosclerosis and blood clots.

Almén realized that the best way to test the concept would be to produce a contrast medium that did not have the same high osmotic pressure.  This required more iodine in each molecule and that the substance did not dissociate while in solution – it had to be ”non-ionized.”

But the Swedish pharmaceutical industry wasn't interested!

Almén contacted a few Swedish pharmaceutical companies but was turned down – their experts had no faith in the concept. At that time Almén was tired of the Swedish tax system, which had refused to allow him to deduct travel expenses for attending a conference. He contacted a Norwegian company and after ironing out a few wrinkles he had a meeting with research director Hugo Holtermann at the Norwegian company Nyegaard; the rest is history.

The company was just about to start developing a new series of contrast media and decided to invest in Almén's idea, even though his molecules were "impossible" according to accepted chemical laws. But it worked and in 1969 the first nonionic contrast medium, Amipaque, was ready for use with spinal anesthesia. Other new contrast media were then manufactured and Nyegaard soon became the predominant producer of contrast media in the world and profited greatly because of the new contrast media.

Nevertheless, Malmö (and Sweden) benefitted from Almén's invention. Nyegaard located a rather large research department at Medeon in Malmö. Torsten Almén, 74, still works there.Nyegaard was bought up a few times and is now owned by General Electric. Meanwhile, happy pensioner Torsten Almén is still chipper and practices playing his oboe from time to time.

Text: Håkan Westling


Portrait Torsten Almén. Photo.

Torsten Almén