Evaluating dopamine transporter activity with 99mTc-TRODAT-1 SPECT in drug-naive Tourette's adults.
OBJECTIVE
Findings on imaging of dopamine transporter (DAT) activity in patients with Tourette's syndrome remain inconclusive. The present study was carried out to observe DAT activity in patients with well-controlled Tourette's syndrome by using (99m)Tc-TRODAT-1 single photon emission computerized tomography (SPECT).


METHODS
Six drug-naive patients with Tourette's syndrome (mean age+/-SD, 21.2+/-1.5 years) were recruited. All met the criteria for Tourette's syndrome established in the DSM-IV. Seventeen age-matched and sex-matched healthy subjects served as the controls. Brain SPECT were acquired 165-195 min after administrating 740 MBq of (99m)Tc-TRODAT-1, using a double-headed camera equipped with ultra-high-resolution fan-beam collimators. The specific uptake ratio was calculated by subtracting the mean counts per pixel in the occipital cortex from the mean counts per pixel in the striatum, putamen or caudate nucleus and by dividing the result by the mean counts per pixel in the occipital cortex. Tic-severity scores were also measured and correlated with the specific uptake ratios.


RESULTS
No significant difference in DAT activity between patients with Tourette's syndrome and control subjects was found in the striatum and its sub-regions. Tic-severity scores were also not correlated with specific uptake ratios measured from the striatum and its sub-regions.


CONCLUSIONS
In conjunction with previous findings, our results suggested that functional abnormality of the dopamine system in patients with Tourette's syndrome might be evident only in its early stage. Adaptation to tic symptoms might play a role in regulating the neural system.
Yeh
Chin-Bin
CB
Department of Psychiatry, National Defense Medical Center, Taipei, Taiwan, ROC.
Lee
Chiang-Hsuan
CH
Chou
Yuan-Hwa
YH
Chang
Chia-Jung
CJ
Ma
Kuo-Hsing
KH
Huang
Wen-Sheng
WS
D000328:Adult; D001921:Brain / Q000473:pathology; D016022:Case-Control Studies; D004298:Dopamine / Q000378:metabolism; D050483:Dopamine Plasma Membrane Transport Proteins / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D009474:Neurons / Q000378:metabolism; D015609:Organotechnetium Compounds / Q000494:pharmacology*; D019275:Radiopharmaceuticals / Q000494:pharmacology*; D015899:Tomography, Emission-Computed, Single-Photon / Q000295:instrumentation* / Q000379:methods*; D005879:Tourette Syndrome / Q000175:diagnosis* / Q000473:pathology*; D014326:Tropanes / Q000494:pharmacology*
D050483:Dopamine Plasma Membrane Transport Proteins; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; D014326:Tropanes; C104196:technetium Tc 99m TRODAT-1; D004298:Dopamine