Published in:
01-04-2012 | Original article
Interobserver variability, and visual and quantitative parameters of 123I-FP-CIT SPECT (DaTSCAN) studies
Published in: Annals of Nuclear Medicine | Issue 3/2012
Login to get accessAbstract
Objective
To evaluate the degree of interobserver agreement in the visual interpretation of 123I-FP-CIT studies and to investigate for potential associations between visual and semi-quantitative parameters.
Methods
Eighty-nine 123I-FP-CIT studies were blindly reviewed by 3 independent observers: a consultant, a resident doctor and a radiographer. They classified every study as either “normal” or “abnormal” and assigned visual 123I-FP-CIT uptake scores (2: normal, 1: reduced and 0: no uptake) in basal ganglia nuclei (right and left putamina and caudate nuclei) on every scan. Striatal 123I-FP-CIT binding ratios were calculated using crescent-ROI software. The interobserver agreement for the interpretation of studies and for visual score assignment was evaluated by means of κ statistics. We investigated for associations of binding ratios with visual scores and clinical parameters; patients’ clinical diagnoses served as the reference standard.
Results
There was excellent interobserver agreement (κ 0.89–0.93) in classifying studies as “normal” or “abnormal” and fine agreement in assignment of visual scores (κ 0.71–0.80 for putamina and 0.50–0.79 for caudate nuclei). Nuclei with scores of 1 and 0 showed significantly reduced binding ratios (about 30 and 50%, respectively) compared with the nuclei scored as 2. ROC analysis indicated the optimal cutoff point of striatal binding ratio at 3.8 (sensitivity 98.5%, specificity 95%) for the detection of parkinsonian syndromes. Striatal binding ratios were negatively associated with age in normal subjects and disease duration in Parkinson’s disease patients.
Conclusion
Visual interpretation of 123I-FP-CIT studies showed very good interobserver agreement. We found significant associations among visual, semi-quantitative and clinical parameters.