Age, Gender, and Diagnostic Performance of Ioflupane I123 Injection (DaTscan™) Brain Imaging in Patients with Movement Disorders and/or Dementia

Background: Although numerous studies have established the sensitivity and specificity of Ioflupane I123 Injection (ioflupane ( 123 I), ( 123 I) FP-CIT, DaTscan TM , or DaTSCAN TM ) imaging in patients with movement disorders or dementia, no studies have examined the effects of gender and age on diagnostic performance. Methods: We pooled data from four clinical trials in which patients with a movement disorder or dementia and healthy volunteers were administered ioflupane ( 123 I). Panels of 3-5 blinded experts and/or on-site nuclear medicine physicians rated the images as normal or abnormal. Results were compared with expert clinical diagnosis (reference standard) to determine sensitivity and specificity. Subgroup and multiple logistic regression model (MLRM) analyses were performed to evaluate the effect of gender and age (two groups: <65 vs. ≥65 yrs and <75 vs. ≥75 yrs) on sensitivity and specificity. Results: There were 421 males and 305 females in the intent-to-diagnose population. Sensitivity was higher for males with parkinsonian syndrome (PS) (93.3% vs. 87.6%; P=0.0029), whereas specificity was higher for females (96.4% vs. 89.5%; P=0.0126). Sensitivity was higher in the younger age groups (<65 yrs, 91.0% vs. ≥65 yrs, 86.8%; P=0.0240 and <75 yrs, 90.7% vs. ≥75 yrs, 78.4%, P < 0.0001). Specificity was higher in subjects <65 yrs (94.0% vs. 89.7% for ≥65 yrs, P=0.0384). Analysis using the 75 yrs cutoff showed no differences. When MLRM was used, all covariates (disease state, age, gender, reader type, and follow-up duration) were significant predictors of the model effect on sensitivity. For specificity, only disease state and reader type were significant predictors. Conclusions: Sensitivity and specificity of ioflupane ( 123 I) imaging was high in all age and gender subgroups, though statistically significant differences were observed with a slightly reduced, though still diagnostically useful, sensitivity above 75 yrs. This reduced sensitivity may be due to increased frequency of mixed pathologies in older people, which makes the clinical diagnosis (reference standard) less optimal. In PS, sensitivity was higher in males, whereas specificity was higher in females. MLRM analysis demonstrated that all tested covariates (including gender and age) were significant predictors for sensitivity, but not for specificity.