The Role of Quantification Values in the Visual Interpretation of Dopamine Transporter PET Images

This study aimed to identify the quantified uptake values that can aid the visual interpretation of dopamine transporter (DAT) PET images.

A total of 155 patients (82 men, 73 women; mean age 67.7 y) who underwent [ 18 F]-N-(3-fluoropropyl)-2β-carboxymethoxy-3β-(4-iodophenyl) nortropane ( 18 F-FP-CIT) PET scans for suspected Parkinson disease were included. Visual assessments classified 18 F-FP-CIT uptake in the basal ganglia [caudate nucleus (CN) and putamen] as normal or abnormal, including the evaluation of asymmetry. The quantitative evaluation involved calculating the SUVR by dividing the basal ganglia SUV by the cerebellum SUV and determining the asymmetric index (AI). This study explored the relationship between these quantification values and visual interpretation, focusing on assessing asymmetric and normal uptake patterns.

Visual analysis indicated that 39.7% (123/310) of CN and 75.8% (235/310) of putamen exhibited abnormal 18 F-FP-CIT uptake. Significant differences in the SUVR and AI values were observed between the visually normal and abnormal groups ( P < 0.001 for both the CN and putamen). The SUVR demonstrated excellent diagnostic accuracy for visual normal uptake patterns in the putamen (AUC = 0.950, 93.2% sensitivity, and 89.3% specificity at a cutoff of 3.91) and CN (AUC = 0.932, 87.0% sensitivity, and 87.7% specificity at a cutoff of 2.73). The AI was also significant in evaluating visual asymmetry (AUC = 0.670, P = 0.004 for the CN; AUC = 0.855, P < 0.001 for the putamen).

Our quantitative measures provide valuable support for the visual interpretation of 18 F-FP-CIT PET images.