The clinical use of 18F-DOPA PET brain in the diagnosis of Parkinson’s disease

Objectives To determine the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 18F-DOPA PET for the diagnosis of Parkinson’s disease (PD) in the clinical setting.

Methods A query of a departmental database was carried out for all patients that underwent L-6-[18F] fluoro-3,4-dihydroxyphenylalnine (18F-DOPA) PET brain scan for motor symptoms suspicious for PD between 2001 and 2007. The patient’s medical records were then assessed for length of follow-up, response to levodopa, clinical course of illness, and laterality of symptoms at time of 18F-DOPA PET. To be eligible in this study the patient had to have at least two years of post-scan clinical follow-up and a diagnosis on or after that time that states whether the patient has PD or not. The eventual diagnosis by the referring Neurologist was used as the gold standard for further analysis. The sensitivity, specificity, PPV, and NPV were then calculated and confidence intervals generated. The confidence interval was calculated using the adjusted-Wald 95% confidence interval method.

Results Twenty-nine patients were found in the initial query, and 2 were excluded (1 uncertain diagnosis, 1 inadequate follow-up). 27 patients (28 scans) remained with 18 males (67%) and 9 female (33%). The median age at scan time was 50.6 years (range: 33-78). Median length of post-scan follow-up was 5.4 years (range: 2-9years). Of the 28 scans, 1 was a false negative, 20 were true positives, 7 were true negatives. There were no false positives. The resultant values are Sensitivity 95.4% (95% CI: 100% -75.3%), Specificity 100% (95% CI: 100%-59.0%), PPV 100% (95% CI 100% -80.7%), and NPV 87.5% (95% CI: 99.5%-50.5%).

Conclusions 18F-DOPA PET appears to be an accurate tool for the diagnosis of PD in the clinic