Test-retest reproducibility of extrastriatal binding with123I-FP-CIT SPECT in healthy male subjects.
123I-labeled 2β-carbomethoxy-3β-(4-iodophenyl)-N-(3-fluoropropyl) nortropane (123I-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 the123I-FP-CIT specific uptake ratio (SUR) in extrastriatal regions. We investigated test-retest reproducibility of123I-FP-CIT binding in the striatum, the midbrain, and cortical regions in eight healthy male subjects. All subjects underwent two123I-FP-CIT SPECT scans, and SUR was calculated using the cerebellum as the reference. We found good test-retest reproducibility of123I-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 that123I-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 that123I-FP-CIT could be used for analyzing SERT in regions with relatively low SERT expression (e.g., temporal or frontal cortices).
Department of Psychiatry, Nara Medical University, Kashihara, Japan.
Kiwamu
K
Matsuoka
Department of Psychiatry, Nara Medical University, Kashihara, Japan. Electronic address: ejm86rp@yahoo.co.jp.
Fumihiko
F
Yasuno
Department of Radiation Oncology, Nara Medical University, Kashihara, Japan.
Takayuki
T
Shinkai
Department of Radiology, Nara Medical University, Kashihara, Japan.
Toshiteru
T
Miyasaka
Department of Psychiatry, Nara Medical University, Kashihara, Japan.
Masato
M
Takahashi
Department of Psychiatry, Nara Medical University, Kashihara, Japan.
Kuniaki
K
Kiuchi
Department of Psychiatry, Nara Medical University, Kashihara, Japan.
Jun
J
Kosaka
Department of Psychiatry, National Hospital Organization Yamato Mental Medical Center, Yamatokoriyama, Japan.
Makoto
M
Inoue
Department of Radiology, Nara Medical University, Kashihara, Japan.
Kimihiko
K
Kichikawa
Department of Radiation Oncology, Nara Medical University, Kashihara, Japan.
Masatoshi
M
Hasegawa
Department of Psychiatry, Nara Medical University, Kashihara, Japan.
Toshifumi
T
Kishimoto
D000328:Adult; D002531:Cerebellum / Q000000981:diagnostic imaging* / Q000378:metabolism; D003342:Corpus Striatum / Q000000981:diagnostic imaging* / Q000378:metabolism; D050483:Dopamine Plasma Membrane Transport Proteins / Q000378:metabolism*; D064368:Healthy Volunteers; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007457:Iodine Radioisotopes; D008297:Male; D008636:Mesencephalon / Q000000981:diagnostic imaging* / Q000378:metabolism; D008875:Middle Aged; D019275:Radiopharmaceuticals / Q000378:metabolism; D015203:Reproducibility of Results; D050486:Serotonin Plasma Membrane Transport Proteins / Q000378:metabolism*; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*; D014326:Tropanes
D050483:Dopamine Plasma Membrane Transport Proteins; D007457:Iodine Radioisotopes; D019275:Radiopharmaceuticals; D050486:Serotonin Plasma Membrane Transport Proteins; D014326:Tropanes; C087552:2-carbomethoxy-8-(3-fluoropropyl)-3-(4-iodophenyl)tropane
(123)I-FP-CIT; Cortex; Midbrain; Reproducibility; SPECT; Serotonin transporter