SPECT/PET Image of the Year Shows Parathyroid Disease in Greater Detail

Researchers selected this image from more than 1,500 studies presented over the course of four days during SNM's 57th annual meeting in June 2010 in Salt Lake City (UT, USA).

"Each year, SNM chooses an image that exemplifies the most cutting-edge molecular imaging research today, as well as illustrates the potential of molecular imaging to provide physicians with a critical component for the detection and diagnosis of disease,” said Michael M. Graham, Ph.D., M.D., immediate past-president of SNM. "This year's Image of the Year provides an example of a novel imaging presentation, using a combination of single photon emission computed tomography [SPECT] with high-resolution CT angiography, which pinpoints the abnormally functioning parathyroid adenoma and the arteries feeding it. With this information, physicians may be able determine the exact location and size of the abnormal gland and plan minimally invasive surgery that reduces operative time, thus improving patient care.”

The SNM Image of the Year shows the potential of fusion of high-resolution three-dimensional (3D) anatomy with functional SPECT images to provide critical information to help physicians to diagnose and treat hyperparathyroidism, an endocrine disease that occurs when the parathyroid glands develop a small adenoma, a benign tumor that produces too much hormone and causes high levels of calcium in the blood. It is usually treated by invasive, exploratory surgery. Using fusion images, physicians can obtain detailed information about the anatomical localization, blood supply, and metabolism of the overactive parathyroid adenoma.

In this study, researchers, from Hokko Memorial Hospital (Sapporo, Japan), scanned 31 patients with symptoms of primary hyperparathyroidism using a nuclear medicine technique called MIBI (methoxyisobutyl isonitrile), combined with SPECT and multidetector computed tomography (MDCT). Researchers obtained thin-slice multiplanar reconstruction images of the neck using a 64-row MDCT with contrast enhancement.

When the enlarged gland was successfully identified, volume-rendered images of the thyroid and parathyroid with feeding arteries were generated. Then, two- and three-dimensional fusion images were also obtained using dedicated workstations. The diagnostic value of three-dimensional SPECT/CT fusion images was compared with those by MIBI SPECT alone and by ultrasound. The study revealed that the hybrid molecular imaging technique was more effective than single modality scanning alone.

A total of 34 glands were identified by surgery. SPECT/CT fusion image, MIBI SPECT, and ultrasound identified 32 (94%), 27 (79%), and 27 (79%) adenomas, respectively. The fusion imaging technique identified five glands that were missed by ultrasound and MIBI SPECT. The fusion images successfully revealed feeding arteries in 29 adenomas. With the use of fusion images for navigation, preliminary results in eight patients showed that operation time is decreased by approximately 82% compared to studies performed without fusion images.

According to the U.S. National Institutes of Health (Bethesda, MD, USA), approximately 100,000 Americans develop hyperparathyroidism each year. Women outnumber men two to one, and risk increases with age. In women 60 years and older, two out of 1,000 will develop hyperparathyroidism each year.

SNM is an international scientific and medical organization dedicated to raising public awareness about what molecular imaging is and how it can help provide patients with the best health care possible. SNM members specialize in molecular imaging, a vital element of today's medical practice that adds an additional level to diagnosis, changing the way common and debilitating diseases are understood and treated.

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