CT Scans and Coffee Don't Mix

Caffeine can cloud image, researchers report

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TUESDAY, June 28, 2005 (HealthDay News) -- Headed for a CT scan? If so, new research suggests it might be best to do without that cup of coffee beforehand.

Researchers at St. Louis University School of Medicine found that caffeine just before a CT scan or positron emission tomography (PET) imaging can obscure scan results.

The study authors noted that most scans to detect or evaluate malignancies are performed using imaging tracers called radiopharmaceuticals, with a tracer called FDG (fluorodeoxyglucucose) being the most common. These tracers go to the heart and provide an image of the heart's function during the scan.

The study found that drinking coffee causes the heart to beat faster and more FDG to appear in the heart region, obscuring the view during the scan. The same thing happens when people exercise before a scan, the researchers added.

This increase of FDG in the heart makes it more difficult to see lesions close to the heart, the study authors said. By avoiding caffeine and exercise before a scan, a patient can improve the likelihood of an accurate scan.

The findings were presented at the recent annual meeting of the Society of Nuclear Medicine in Toronto.

More information

The Society of Nuclear Medicine has more about PET.

SOURCE: Saint Louis University, news release, June 2005

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