[Quantitative evaluation of 123I-FP-CIT SPECT: validation of a semiautomated method]

Area of Science:

• Nuclear Medicine
• Neurology
• Radiopharmacology

Background:

• 123I-FP-CIT SPECT imaging is used to evaluate nigrostriatal dopaminergic pathways.
• Accurate quantification is crucial for differentiating Parkinson's disease from other parkinsonian syndromes.

Purpose of the Study:

• To establish reference values and normal ranges for 123I-FP-CIT uptake quantification.
• To assess the interobserver variability of the quantification method.

Main Methods:

• Fifty patients underwent 123I-FP-CIT SPECT (25 Parkinson's disease, 25 controls with drug-induced or psychogenic parkinsonism).
• Regions of Interest (ROIs) were applied to SPECT slices to calculate specific (caudate, putamen) and non-specific (occipital) uptake ratios.
• Statistical analysis included mean, standard deviation, range, variation coefficient, and correlation coefficient between two observers.

Main Results:

• The quantification method demonstrated high interobserver reproducibility (variation coefficient 3.24-5.61, correlation coefficient 0.89-0.99).
• Cut-off values were established for the putamen (right: 2.10, left: 2.05) to differentiate Parkinson's disease from controls.
• Cut-off values for the caudate nucleus were not reliably established due to overlapping ratios.

Conclusions:

• The 123I-FP-CIT uptake quantification method is highly reproducible.
• This technique enables the establishment of reference values and normal ranges for SPECT imaging.
• The findings support the utility of this quantitative approach in diagnosing Parkinsonian syndromes.