A New Era of Clinical Dopamine Transporter Imaging Using ¹²³I-FP-CIT

Brain ¹²³I-FP-CIT SPECT images. Transaxial slices at striatal level. (A) Normal ¹²³I-FP-CIT uptake, which is often described as comma shaped, is seen in healthy subject. (B) Striatal uptake is decreased in patient with PD. Reduction is more prominent in putamen than in caudate nucleus.

Superior spatial resolution of brain ¹⁸F-FP-CIT PET images. Superior spatial resolution of brain PET enables us to see caudate nucleus and putamen separately, and to analyze small brain structures such as in brain stem area. Another advantage of ¹⁸F-FP-CIT PET is that it can be acquired 2–3 h after injection.

Variety of diseases mimicking idiopathic PD.

Differential diagnosis of parkinsonism using brain ¹⁸F-FP-CIT PET. Brain PET/CT images of ¹⁸F-FP-CIT uptake at level of striatum demonstrate different DAT density in different conditions. DAT density is decreased in PD patient (B), whereas DAT density is normal in healthy subject (A) and in patients with drug-induced parkinsonism (C) and essential tremor (D). DAT imaging is useful for differential diagnosis of various causes of parkinsonism. Clinical diagnosis of parkinsonism is quite often straightforward, obviating additional tests, but when overlap and incomplete syndromes are present, improvements in diagnostic accuracy may be possible using DAT imaging.

Differential diagnosis of dementia using brain ¹²³F-FP-CIT SPECT. The 2 most common forms of dementia, Alzheimer disease (AD) and DLB, share clinical features and are often difficult to differentiate. ¹⁸F-FDG PET is useful when typical bilateral temporoparietal hypometabolism is seen in AD and occipital hypometabolism is seen in DLB, as demonstrated in these images; however, that is not always case. With DAT imaging, for example, using ¹²³I-FP-CIT, these 2 disorders can be more easily distinguished. Striatal dopaminergic deficit occurs in DLB but not in AD.