PET builds case in Parkinson's diagnosis

A functional marker detected with PET scanning may help early diagnosis of Parkinson's disease, according to researchers in the U.S and U.K. Trial results may lead to better understanding of PD's progression and treatment.

Investigators from the University of Pittsburgh and the Imperial College of Medicine in London scanned 41 patients with PD and 16 healthy subjects using PET with F-18 dopa. After gauging F-18 dopa uptake in the locus coeruleus and midbrain raphe, they found evidence of nerve cell degeneration in these areas in PD patients.

"We were able to see changes in these areas for the very first time," said lead author Dr. Robert Y. Moore, codirector of UP's National Parkinson Foundation Center of Excellence.

He presented trial results April 2 at the American Academy of Neurology meeting in Honolulu.

F-18 dopa uptake in the early PD patients' raphe was higher than that of normal individuals, while uptake in the locus coeruleus was similar in both groups. Advanced PD patients, however, showed a lower F-18 dopa uptake than controls in both the locus coeruleus and raphe.

Until now, these changes could be seen only on postmortem examination. This study showed that both degenerative and compensatory changes in PD can be documented in vivo during the course of the disease in monoaminergic nuclei outside the nigrostriatal system using PET.

PET may help develop ways to diagnose PD early and even to identify asymptomatic people who are at risk of developing the disease, Moore said. Nigrostriatal dopaminergic neurons' loss usually begins several years before PD symptoms appear.

A cure for Parkinson's disease is nowhere near. Advances in the field, however, have improved treatment and show promise for the development of neuroprotective therapies, which may help delay the progression of the disease and prevent severe disability from occurring, according to Moore.

"There are several drugs now in FDA phase I and II trials that hold promise for this," he said.

For more from the Diagnostic Imaging archives:

Transcranial ultrasound shows promise for Parkinson's diagnosis
http://www.dimag.com/db_area/onlinenews/2003/2003021901.shtml

Agent improves diagnosis of Parkinson's
http://www.dimag.com/db_area/archives/2003/0302.overread5.di.shtml