The nasal cilia scan used to show whether the tiny hairs in the nose were functioning properly and clearing away mucus. The scanner tracked the movement of a radioactive droplet in the nose. But the result was rarely clear. And on top of that: 'One sneeze, and the scan failed.'
Entire carpets of millions of microscopic nasal cilia, as pediatric pulmonologist Jolt Roukema from Radboudumc puts it, 'do the wave fifteen times a second.' With those wave-like movements, they transport mucus toward the throat at a speed of about eight millimeters per minute. That mucus is full of dust and pathogens and can then be swallowed or coughed up. The result: a perfectly clean nose five times an hour.
But in some people, these cilia do not work properly from birth. How do you find that out? 'In the past, we did a nasal cilium scan', says Martin Engels, the retired lab technician who supervised scans at Radboudumc for forty years. 'The patient received a tiny droplet of mildly radioactive fluid in the nose. Using a scanner, we could measure the radioactivity and track whether the cilia were moving the droplet neatly toward the throat.'
For this scan, the patient had to sit completely still for twenty minutes. Since the scan was almost always performed on children, this often proved to be a challenge. Engels: 'And on top of that: one sneeze, and the scan failed. So it often didn’t go well.'
Congenital abnormality
'But even when the scan was performed correctly, it unfortunately wasn’t always useful, let alone conclusive', says Roukema. 'If you saw the droplet move neatly and quickly, you could conclude that the cilia were functioning properly, and a cilia-related issue became much less likely. But if the droplet didn’t move, you still didn’t know what was going on.'
If the cilia move poorly or not at all, that does not automatically mean there is an inherited, and therefore congenital, abnormality underneath—such as primary ciliary dyskinesia. It could also be that someone simply has a cold, or recently had one. A virus apparently also reduces ciliary movement, and this effect can last for several weeks.
Cross-section of the upper layer of the nasal mucosa. The microscopic hairs on top of the cells neatly clean the nose five times an hour.
Moving cilia under the microscope
By now, the nasal cilia scan has been replaced with other tests. It starts with a consultation and physical examination: people with cilia problems often suffer from coughing, colds and ear infections. Then comes a breath test, because in cilia-related issues the exhaled air often shows abnormalities. A genetic test is also important, as mutations in as many as 55 different genes can cause abnormal cilia. Genetic research now provides answers for about seventy percent of people with a congenital cilia disorder. Sometimes a biopsy of the nasal mucosa is needed at a specialized center, where the ciliated cells end up under a microscope for a detailed video recording of their movements.
Still, according to Roukema, a single test rarely provides one hundred percent certainty, and a combination is almost always necessary. If the diagnosis remains difficult, Roukema sometimes thinks back to the nasal cilia scan. 'A low-burden scan that could rule out problems quite well—I didn’t think that scan was so bad.'
Image above: Martin Engels, now retired, worked as a radiographer and supervised scans at Radboudumc for forty years. Here he stands next to the gamma camera that was also used to perform the nasal cilia scan. Photographer Jan van Teeffelen, 1989.
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Annemarie Eek
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