Article type: Literature Review
Article title: Clinical utility of DaTscan in clinically uncertain parkinsonian syndromes: a systematic review and meta‑analysis
Journal: Journal of Clinical Neuroscience
Year: 2026
Authors: Jamir Pitton Rissardo, Jorge Patino, Ana Letícia Fornari-Caprara, and Andrew McGarry
E-mail: jamirrissardo@gmail.com
ABSTRACT
Background: Clinically uncertain parkinsonian syndromes (CUPS) pose diagnostic challenges, particularly in distinguishing degenerative from non‑degenerative etiologies. DaTscan (123I-ioflupane SPECT) is frequently used to clarify ambiguity, but the magnitude of its diagnostic impact across different initial clinical suspicions remains unclear. Methods: A systematic review of MEDLINE, EMBASE, PsycINFO, and the Cochrane Library was conducted from January 2002 to February 2026, with no language restrictions. Studies reporting a diagnostic change after DaTscan were included. Two reviewers independently performed screening, data extraction, and quality assessment using ROBINS‑I tool. Proportions were pooled using a random‑effects model with Restricted Maximum Likelihood. Exact Clopper–Pearson intervals were calculated. Results: Seventy‑five observations comprising 2,232 patients were included. The pooled proportion of diagnostic revision was 0.32 (95 % CI 0.26–0.38; I2 = 80 %). Diagnostic changes were most frequent among patients initially suspected of vascular parkinsonism (0.53; 95 % CI 0.37–0.69; I2 = 55 %) and drug‑induced parkinsonism (0.38; 95 % CI 0.28–0.49; I2 = 38 %). Revisions also occurred in cases initially labeled as functional movement disorder (0.35; 95 % CI 0.23–0.49; I2 = 0 %), essential tremor (0.27; 95 % CI 0.18–0.38; I2 = 62 %), and Parkinson’s disease (0.22; 95 % CI 0.17–0.33; I2 = 92 %). Conclusions: DaTscan was associated with diagnostic revision in approximately one‑third of patients with CUPS, with the greatest impact in vascular and drug‑induced parkinsonism. These findings support a role for DaTscan as an adjunct to clinical assessment when diagnostic uncertainty persists.
Keywords: CUPS; Parkinsonism; 123I-Ioflupane; DAT; SPECT.
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DOI
Citation
Rissardo JP, Patino J, Fornari Caprara AL, McGarry A. Clinical utility of DaTscan in clinically uncertain parkinsonian syndromes: a systematic review and meta‑analysis. J Clin Neurosci 2026;154:2026:112305. doi: 10.1016/j.jocn.2026.112305.
Figure 1. PRISMA flowchart for the identification of included studies. Automated database filtering refers to database search and record-management functions used during literature retrieval and duplicate removal. No automated study-screening or eligibility-assessment tools were used; all screening decisions were performed independently by two reviewers.
Figure 2. Quality assessment of all eligible studies based on robvis.
Figure 3. Forest plot of pooled proportions of diagnostic change after DaTscan across primary diagnostic categories. Each point represents the study‑level pooled proportion for a diagnostic category, with horizontal bars denoting corresponding 95 % confidence intervals. The diamond at the bottom represents the overall pooled estimate.
Figure 4. Forest plot of diagnostic change proportions for patients initially suspected of ET. Each point represents the study‑level pooled proportion for diagnostic change, with horizontal bars denoting corresponding 95 % confidence intervals. The diamond at the bottom represents the overall pooled estimate.
Figure 5. Forest plot of diagnostic change proportions for patients initially suspected of PD. Each point represents the study‑level pooled proportion for diagnostic change, with horizontal bars denoting corresponding 95 % confidence intervals. The diamond at the bottom represents the overall pooled estimate.