Clinical utility of DaTscan in clinically uncertain parkinsonian syndromes: a systematic review and meta‑analysis.
J P Rissardo, J Patino, A L Fornari Caprara et al.
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In 30 seconds
This systematic review and meta-analysis assessed how often DaTscan (123I-ioflupane SPECT) was followed by a diagnostic change in patients with clinically uncertain parkinsonian syndromes. Across 75 observations comprising 2,232 patients, the pooled proportion with diagnostic revision was 0.32 (95 % CI 0.26-0.38; I 2 = 80 %). Changes were most frequent when vascular parkinsonism was initially suspected (0.53; 95 % CI 0.37-0.69) and when drug-induced parkinsonism was suspected (0.38; 95 % CI 0.28-0.49).
Key findings
- Diagnostic revision after DaTscan occurred in a pooled 0.32 of patients (95 % CI 0.26-0.38; I 2 = 80 %).
- Revision was most frequent with initial suspicion of vascular parkinsonism: 0.53 (95 % CI 0.37-0.69; I2 = 55 %).
- For suspected drug-induced parkinsonism, the revision proportion was 0.38 (95 % CI 0.28-0.49; I2 = 38 %).
- Revisions were also reported for initial diagnoses of functional movement disorder (0.35), essential tremor (0.27), and Parkinson's disease (0.22).
Why it matters
Diagnostic uncertainty can complicate assessment of parkinsonian syndromes, particularly when distinguishing degenerative from non-degenerative causes. The pooled findings indicate that DaTscan is often associated with a change in diagnosis, especially in patients initially thought to have vascular or drug-induced parkinsonism. This helps characterize its potential value as an adjunct to clinical assessment, while the substantial heterogeneity in the overall estimate warrants caution.
What to keep in mind
The pooled estimate showed substantial heterogeneity (I 2 = 80 %), and the included studies reported diagnostic change rather than establishing improved patient outcomes.