Objective: To describe further changes in DaT scan utilization and its influence on management following our initial experience.  

Background: We previously reported our DaT scan experience for the first 175 patients and showed: 1) high scan utilization rate and scan utilization variability amongst clinicians (5 to 33 per 100 new patients); 2) surprisingly low pre-scan diagnostic accuracy rate (i.e. compatibility percentage of the working diagnosis to scan results)– 57% for neurodegenerative parkinsonism, 65% for non-neurodegenerative parkinsonism, 79% for essential tremor (ET), and 47% for psychogenic movement disorder; and, 3) high treatment discrepancy rate (i.e. the percentage of inconsistency of treatment with scan results) especially among  patients with normal scans  (24% continued on  anti-parkinson medication).

Methods: We conducted a retrospective review of the next set of consecutive patients, evaluated by movement disorder neurologists, who received a DaT scan from November 2012 to May 2014.  

Results: A total of 200 (out of 240) scans performed during the 19-month period were included in our analysis.  The rates of scan utilization decreased to 0 to 13 per 100 new patients, although utilization variability remained wide.  Clinicians’ pre-scan diagnostic accuracy improved (i.e. when neurodegenerative parkinsonism was suspected (N=97), the scan was abnormal in 73.2% of the cases.; when non-neurodegenerative parkinsonism was suspected (N=40), the scan was normal in 80% of cases; this included psychogenic movement disorders (N=19) with a normal scan in 79%; and, when ET was the pre-scan diagnosis (N=28), the scan was normal in 86%).  Treatment discrepancy reduced especially with normal scan results (i.e. only to 7% ofpatients with a normal scan remained on PD medications). 

Conclusions: While scan utilization rates among specialists reduced over time, utilization variability remained wide and treatment became more concordant with DaT scan results. Surprisingly, with continued experience using DaT scans, our clinicians’ pre-scan diagnostic accuracy improved over time. 

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MDS Abstracts - https://www.mdsabstracts.org/abstract/evolution-in-dopamine-transporter-dat-scan-utilization-patterns-and-its-effect-on-treatment-decisions-results-of-the-next-200-scans/