Diagnostic Reliability of DaTscan in Movement Disorders (P03.125)

Objective: To analyze accuracy and reliability of visual assessment of I-123 ioflupane DaTscan (GE Healthcare, Princeton, NJ) in the diagnosis of movement disorders and to propose a rating scale for image interpretation. Background Since approval by the Food and Drug Administration (FDA), DaTscan has been increasingly used in the evaluation of patients with parkinsonism. Visual assessment, a mainly descriptive technique based on Benamer9s criteria (Benamer, Mov Disord 2000; 15:503-10) for grading abnormal patterns of striatal radiotracer uptake, remains the main interpretation method of the images. The diagnostic accuracy of DaTscan since its FDA approval has not been previously reported. Design/Methods: 9 raters experienced in movement disorders or nuclear medicine, blinded to the clinical diagnosis, interpreted 21 DaTscans individually and in consensus. Raters interpreted scans according to Benamer9s criteria and commented on asymmetry of striatal uptake. The consensus interpretation was compared to clinical diagnosis: Parkinson9s disease (PD) (N=14), essential tremor (ET) (N=1), healthy controls (N=6). The mean symptom duration among PD patients was 4.0 years (SD ±2.22, range 1- 9 years), mean UPDRS III score was 15.15; (SD ±13.46, range 1-42). The sensitivity, specificity, positive and negative predictive values of the consensus, and the inter-rater reliability of individual visual interpretations were calculated. Results: Sensitivity of identifying abnormal scans was 1.0 for consensus review. Specificity was 0.714, negative predictive value 1.0, positive predictive value 0.875. Two subjects had false-positive images (1 healthy control, 1 ET). Inter-rater reliability was 0.948 for identifying abnormal scans, 0.896 for grading abnormal scans, 0.790 for detecting asymmetry of decreased uptake. Conclusions: Visual assessment of DaTscan images has high sensitivity and inter-rater reliability in detecting abnormal scans, but its clinical utility may be enhanced by reliable recognition of altered patterns of striatal uptake. A new rating scale for visual assessment is proposed that may increase reliability of the image interpretation. Disclosure: Dr. Waln has nothing to disclose. Dr. Jimenez-Shahed has received personal compensation for activities with Teva Neuroscienece, Allergan, Inc., Merz Pharma, Medtronic, Inc., and Lundbeck Research USA, Inc. Dr. Wendt has nothing to disclose. Dr. York has nothing to disclose. Dr. Baizabal Carvallo has nothing to disclose. Dr. Mehanna has nothing to disclose. Dr. Patel has nothing to disclose. Dr. Patel has nothing to disclose. Dr. Hunter has received personal compensation for activities with Lundbeck Research USA, Inc. as a consultant. Dr. Van has nothing to disclose. Dr. Jankovic has received personal compensation for activities with Allergan, Inc., Chelsea Therapeutics, Serono Inc., Merz Pharma, Lundbeck Research USA, Inc, Teva Neuroscience as a consultant. Dr. Jankovic has received personal compensation in an editorial capacity for Medlink: Neurology in Clinical Practice. Dr. Jankovic has received research support from Allergan, Inc, Allon Therapeutics, Ceregene, Inc., Chelsea Therapeutics; Diana Helis Henry Medical Research Foundation, Serono Inc., Huntington9s Disease Society of America, Huntington Study Group, Impax Pharmaceuticals, Ipsen Limited, Lundbeck Research USA, Inc.