AAN: DaTscan SPECT on display for diagnosis of dopamine disorders

Data from multiple clinical trials for DaTscan (I-123 FP-CIT Ioflupane) using SPECT shows that the exam is very sensitive for detecting striatal dopaminergic deficits, according to a presentation during the American Academy of Neurology being held April 26 through May 3 in Philadelphia.

Dopamine disorder in this area of the brain is an essential trait of Parkinson’s tremor and dementia with Lewy bodies. For all four presented clinical trials, sensitivity of DaTscan for determining dopamine deficiency was gauged at 91.9 percent and specificity 83.6 percent. Blind assessment by independent readers revealed the sensitivity and specificity to be 88.7 percent and 91.2 percent, respectively.

Presenter Donald Grosset, MD, consultant neurologist at the Institute of Neurological Sciences in Glasgow, Scotland, as well as an honorary professor of neurology at the University of Glasgow, took some time out from the conference to speak with Molecular Imaging.

In the case of movement disorders, DaTscan SPECT can tell Parkinson’s tremor from other forms of tremor because of the dopamine deficiency associated with Parkinsonism.

“To be more specific, the presynaptic dopamine system is abnormal in these cases,” explained Grosset. “We have patients who look very similar in terms of their clinical history and examination, but they have the more benign tremor of essential tremor. This is the first hearing of evidence for the presence or absence of dopamine deficiency.”

In term of dementias, Alzheimer’s and vascular dementia do not portray any dopamine disorder. However, dementia with Lewy bodies does. “In patients where there is clinical uncertainty between these diagnoses, we can do this scan, which can tell us whether or not we are dealing with dopamine deficiency disorder,” said Grosset.

Dopamine replacement therapy is currently available to treat dopamine deficiency, particularly for Parkinson’s patients. The emergence of a scan for these diseases could help in the treatment selection process.

“If they have dopamine deficiency disorder, we can then introduce dopamine replacement therapy and anti-Parkinson’s therapy,” he added. “If they do not, then we do not go down that treatment avenue.”