Nuclear Medicine Test Could Pinpoint Parkinson's Disease Earlier

CINCINNATI—Enabling earlier diagnosis and treatment of Parkinson's disease is the goal of a nuclear medicine test now being offered at UC Health University Hospital.

The test uses a unique imaging agent—known as DaTscan, the first and only radiopharmaceutical approved by the Food and Drug Administration to help physicians evaluate patients with tremors and other warning signs of Parkinson's disease. The chronic and progressive movement disorder has no known cure. The team expects to scan its first patient in early September. 

Developed by GE Healthcare, DaTscan works by combining a drug compound labeled with a commonly used radioactive tracer which is injected into the patient's bloodstream. It then travels to the central nervous system and is absorbed by specific cells in the brain that transmit dopamine.

Nuclear medicine physicians then use a SPECT (single photon emission computed tomography) camera to capture 3D images that show nerve function and dopamine receptor activity in the upper midbrain. Dopamine is a chemical involved in generating and controlling movements and other central nervous system functions. When dopamine is deficient, movements become impaired as is the case in Parkinson's disease.

"We know that symptoms of Parkinson's are caused by loss of nerve cells in the substantia nigra, a region in the upper midbrain. Loss of these cells causes a depletion of dopamine at a higher level in the brain called the striatum," explains Mariano Fernandez-Ulloa, MD, director of nuclear medicine at University Hospital and professor at the UC College of Medicine.  "By scanning the brain using DaTscan we can assess the degree of loss of dopamine function in the striatum, which is typically observed in patients with Parkinson's disease. This diagnostic tool complements other important clinical assessment performed by the neurologist." 

SPECT images are analyzed as a series of "slices" and then fused with other brain imaging tests (magnetic resonance imaging, computed tomography) to create a detailed visual map of nerve function in the brain.

Alberto Espay, MD, says studies indicate that DaTscan can greatly assist in the diagnosis of patients with Parkinson's disease at early stages or with atypical presentations, and for whom diagnostic uncertainty exists.

"Determining the nature of tremors and other movement abnormalities in parkinsonian conditions is at the mercy of a physician's judgment. In many instances, a firm diagnosis of Parkinson's disease is difficult to reach because it can present in so many different ways," explains Espay, a UC Health neurologist with the UC Neuroscience Institute's Gardner Center for Parkinson's Disease and Movement Disorders. Espay is also an associate professor at the UC College of Medicine. "Studies indicate that DaTscan can greatly assist in the diagnosis of patients with Parkinson's disease at early stages or with atypical presentations, and for whom diagnostic uncertainty exists."

"We hope this tool will enhance our ability to distinguish Parkinson's disease from other causes of motor abnormalities that may look like it. It may also prove important for earlier diagnosis, especially as we prepare to examine pharmacological treatments that may slow down the disease,"adds Fredy Revilla, MD, associate professor at the College of Medicine and director of the Gardner Center.

According to the National Institute of Neurologic Disorders and Stroke, more than 1 million people are believed to suffer from Parkinson's disease and 50,000 are diagnosed annually. Common symptoms of the disease include tremors, slow movement or the inability to move, rigid limbs, a shuffling gait and stooped posture. 

For more information on the UC Health movement disorder specialists, visit ucphysicians.com. More information on the Gardner Center is available at ucgardnercenter.com. 

University Hospital accredited by the American College of Radiology (ACR) for all types of diagnostic imaging, including nuclear medicine—an honor UC Health holds exclusively in the Cincinnati area. University Hospital and the physicians affiliated with the Gardner Center have no financial interest in GE Healthcare.