To determine the accuracy of DAT-SPECT imaging in assessing presynaptic dopaminergic denervation in the setting of medications that may interfere with scan results. 

Parkinson’s disease (PD) is characterized pathologically by early loss of dopaminergic neurons, resulting in cardinal motor features of bradykinesia, rigidity, and tremor. In practice, DAT-SPECT (ioflupane [123I] SPECT) imaging is approved as a diagnostic tool for the evaluation of suspected Parkinsonian syndromes, but the FDA approved package insert lists 16 potential medications that may interfere with the image obtained. The clinical impact of these medications upon DAT-SPECT imaging results has not been established, nor is it a universal practice to stop these drugs when ordering a DaTscan. 

This is a retrospective chart review of all patients at a single center who underwent DAT-SPECT imaging while taking “contraindicated” medications between December 2012 to December 2022. This was accomplished by reviewing scan results as being consistent or inconsistent with a diagnosis of PD and then comparing the initial diagnosis with a clinical follow-up to assess whether the scan results match the clinical outcomes. Sensitivity, specificity, positive predictive value, and negative predictive value were calculated for each drug.

A total of 1224 charts were screened, and 153 (12.5%) charts met the inclusion criteria. Bupropion (32%, n=49) and sertraline (26%, n=40) were the most common contraindicated medications. The false positive rate was 9.2%.  

This retrospective analysis supports the concern that certain medications may interfere with DaTscan results and that some patients remain on these medications while obtaining DaTscans, leading to potential for false positive results.  Further analysis will provide a more specific characterization of the correlation between drug interactions and DaTscan results, including dosages, time on medication, and duration of follow up.