Test-retest reproducibility of extrastriatal binding with 123 I-FP-CIT SPECT in healthy male subjects

• Published in: Psychiatry research. Neuroimaging Vol. 258; pp. 10 - 15
• Main Authors: Matsuoka, Kiwamu, Yasuno, Fumihiko, Shinkai, Takayuki, Miyasaka, Toshiteru, Takahashi, Masato, Kiuchi, Kuniaki, Kosaka, Jun, Inoue, Makoto, Kichikawa, Kimihiko, Hasegawa, Masatoshi, Kishimoto, Toshifumi
• Format: Journal Article
• Language: English
• Published: Netherlands 30.12.2016
• Subjects: Adult; Cerebellum - diagnostic imaging; Cerebellum - metabolism; Corpus Striatum - diagnostic imaging; Corpus Striatum - metabolism; Dopamine Plasma Membrane Transport Proteins - metabolism; Healthy Volunteers; Humans; Image Processing, Computer-Assisted; Iodine Radioisotopes; Male; Mesencephalon - diagnostic imaging; Mesencephalon - metabolism; Middle Aged; Radiopharmaceuticals - metabolism; Reproducibility of Results; Serotonin Plasma Membrane Transport Proteins - metabolism; Tomography, Emission-Computed, Single-Photon - methods; Tropanes; I-FP-CIT; Midbrain; Serotonin transporter; Reproducibility; SPECT; Cortex
• ISSN: 0925-4927; 1872-7506
• DOI: 10.1016/j.pscychresns.2016.10.007

I-labeled 2β-carbomethoxy-3β-(4-iodophenyl)-N-(3-fluoropropyl) nortropane ( I-FP-CIT) is used to assess striatal dopamine transporter (DAT) expression, but it can also quantify extrastriatal serotonin transporter (SERT) expressions. While FP-CIT uptake in extrastriatal regions has been quantified, no information exists on the reproducibility of the I-FP-CIT specific uptake ratio (SUR) in extrastriatal regions. We investigated test-retest reproducibility of I-FP-CIT binding in the striatum, the midbrain, and cortical regions in eight healthy male subjects. All subjects underwent two I-FP-CIT SPECT scans, and SUR was calculated using the cerebellum as the reference. We found good test-retest reproducibility of I-FP-CIT SUR in the midbrain, and in the lateral frontal/temporal cortex and combined cortical regions. The overall variability and intraclass correlation of SUR were, respectively, 4.9-7.8% and 0.90-0.96 in striatal regions, 8.6% and 0.79 in the midbrain, and 3.6-9.1% and 0.84-0.95 in the lateral frontal/temporal cortex and combined cortical regions. Our results provide evidence that I-FP-CIT SPECT is a valid technique for analyzing striatal DAT, as well as extrastriatal SERT in areas such as the SERT-enriched midbrain. In addition, our data suggest that I-FP-CIT could be used for analyzing SERT in regions with relatively low SERT expression (e.g., temporal or frontal cortices).