Fully Automated Quantification of the Striatal Uptake Ratio of [^99mTc]-TRODAT with SPECT Imaging: Evaluation of the Diagnostic Performance in Parkinson’s Disease and the Temporal Regression of Striatal Tracer Uptake

Figure 5

The relationship between the onset duration and the uptake ratio. Each data point represents the SRR mean of that particular year of clinical duration, and the error bars represent the SD. A quadratic function, shown as the solid curve, was used to fit the data points. The was 0.8446. Based on this quadratic function and the mean SRR of 2.02 in the healthy controls, a preclinical duration of 11.3 years was estimated with curve extrapolation.