Abstract
Introduction
Dopamine transporter scan (DaT scan) nuclear imaging can be a useful tool in the diagnostic work up of conditions such as Parkinson’s disease (PD) where the underlying physiology of the disease involves striatal dopamine transporter loss. Selective serotonin reuptake inhibitors (SSRIs) bind with high affinity to the dopamine transporter, competing with test compound, ioflupane. There is inconsistent guidance on stopping SSRIs prior to DAT scan due to lack of robust evidence. However, case studies suggest the interaction may result in false positive results. We investigated potential SSRI related false positive DaT scan results in view of developing a local guideline.
Methods
DaT Scan reports of patients attending two district general hospitals in South Wales over a one year period were retrospectively analysed and cross-referenced with their diagnosis and drug history on Welsh Clinical Portal (WCP).
Results
Seventy two patient records were analysed. Mean age was 73 and 64% were male. Eight patients (11%) were taking an SSRI at the time of their DaT scan. Patients taking SSRIs were not more likely to have a positive DaT scan result than patients not on SSRIs (7/8 and 40/64 respectively, p = 0.598). Those taking SSRIs were also not more likely to have a clinical diagnosis of PD than those not taking SSRIs (5/8 and 27/64 respectively, p=0.451).
Conclusion
In our evaluation SSRIs did not increase the likelihood of false positive DaT scan results. As absence of evidence is due to few and small number studies, we employ a pragmatic approach of considering stopping or continuing SSRIs prior to DaT on a case-by-case basis and interpreting results in context, with consideration of repeat scan off SSRI if appropriate.