Justification and impact of SPECT ¹²³I-FP-CIT use in the differential diagnosis and management of movement disorders (MD) in a national referral hospital.

¹²³I-FP-CIT SPECT is a key tool in the differential diagnosis of movement disorders (MD), but its appropriate indication is essential to optimize resources and avoid unnecessary tests.

Aim: To evaluate the adequacy and impact of ¹²³I-FP-CIT SPECT in the diagnosis and management of MD according to clinical guidelines.

Patients and methods: Retrospective study involving 249 patients with suspected parkinsonism (PK) of uncertain origin. All underwent ¹²³I-FP-CIT SPECT and had a clinical follow-up of exceeding 12 months. Requests were classified based on their adherence to clinical guidelines. Variables analyzed included sex, age, justification for the request, management after SPECT, and final diagnosis.

Results: 91.57% of the requests were appropriate, while 8.43% did not adhere to the guidelines. Diagnosis changed in 48.6% of cases and management in 70.68% after the scan, especially in inconclusive cases and initiation of therapy. General neurologists evaluated more cases and made more appropriate requests (96.3% vs 76.67%; p<0.001). However, MD specialists, despite less appropriate use of the guidelines, achieved a higher number of conclusive diagnoses in complex cases.

Conclusion: ¹²³I-FP-CIT SPECT has significant clinical impact when used in accordance with clinical guidelines, improving the diagnosis and management of MD. Unjustified scans reduce its utility. Collaboration between general neurologists and MD specialists is fundamental; the latter, although showing less adherence to guidelines in requesting the test, achieve a higher number of conclusive diagnoses in complex cases.