Semiquantitative analysis using standardized uptake value in ¹²³I-FP-CIT SPECT/CT

Area of Science:

• Nuclear Medicine
• Radiochemistry
• Neurology

Background:

• 123I-FP-CIT SPECT/CT is used to assess presynaptic dopaminergic deficits in neurodegenerative diseases.
• Standardized Uptake Value (SUV) and Specific Binding Ratio (SBR) are quantitative parameters used in SPECT imaging.
• Evaluating semiquantitative SUV methods against SBR is crucial for accurate diagnosis.

Purpose of the Study:

• To compare the diagnostic potential of semiquantitative Standardized Uptake Value (SUV) with Specific Binding Ratio (SBR) in 123I-FP-CIT SPECT/CT.
• To assess the accuracy of SUV measurements in a phantom study.
• To determine the efficacy of SUV-based parameters versus SBR in differentiating neurodegenerative diseases.

Main Methods:

• A phantom study validated SUV measurement accuracy.
• 52 patients with neurodegenerative diseases underwent 123I-FP-CIT SPECT/CT.
• SBR, various SUV metrics (max, peak, mean, ratio), and striatum-to-background SUV ratio (SUVratio) were calculated and compared with SBR using Pearson's correlation and diagnostic accuracy metrics.

Main Results:

• Phantom study showed SUV errors <10%.
• SUVratio demonstrated the strongest correlation with SBR (r=0.877, p<0.001).
• SBR outperformed SUVratio in diagnosing neurodegenerative diseases (accuracy: 92.3% vs 88.5%), with higher sensitivity (92.5% vs 85.0%) and comparable specificity (91.7% vs 100%).

Conclusions:

• Specific Binding Ratio (SBR) is a reliable parameter for aiding the differential diagnosis of neurodegenerative diseases.
• While SUV is technically acceptable, it may not offer superior clinical utility compared to SBR in 123I-FP-CIT SPECT/CT.
• SBR remains the preferred method for assessing presynaptic dopaminergic deficits with 123I-FP-CIT SPECT/CT.