PET/CT imaging of striatal dopamine transporters in a newborn piglet model of hypoxic-ischemic brain injury

Objective: To investigate changes of striatal DAT following hypoxic ischemic (HI) brain injury in newborn piglets using ¹¹C-N-2-carbomethoxy-3-(4-fluorophenyl)-tropane (CFT) PET/CT, and to evaluate the value of ¹¹C-CFT PET/CT in brain injury. Methods: Newborn piglets with HI brain injury (n=20) were taken as a model group,and five piglets were used as a control group. Radioligand ¹¹C-CFT (55.5-74.0 MBq) was injected through the jugular vein, and PET/CT imaging was performed to observe the changes of striatal DAT in newborn piglets. The ST/occipital lobe (OC) ratio was calculated. Model group was divided into 0-6 h, 20-24 h, 44-48 h and 68-72 h sub-groups after HI in accordance with the imaging time. The piglets were sacrificed immediately after ¹¹C-CFT PET/CT scanning, and then the brains were removed for pathological analysis. Data analysis was performed with one-way analysis of variance and Pearson linear correlation analysis. Results: After intravenous injection of ¹¹C-CFT, the radioactivity accumulation in cortical, striatum, and cerebellum was shown clearly in the control and model groups. The radioactivity accumulation was lower in the white matter. The radioactivity in cortical and cerebellum exhibited decreased with time, while the striatum was still clear. After HI, the ST/OC activity ratio in the striatum was initially increased, and the ratio of 0-6 h group (1.34 ± 0.04) was statistically significant compared with that of the control group (1.18 ± 0.06; F=4.658, P<0.05), followed by a gradual decrease. ST/OC ratios of other HI subgroups were 1.27 ±0.01, 1.27 ±0.10 and 1.18 ±0.05, respectively. There was a positive correlation between the number of DAT positive neurons ((13 ± 3), (13 ± 4), (8 ±3) and (4 ±4)/high power field) and ¹¹C-CFT ST/OC activity ratios (r=0.844, P<0.05). Conclusion: ¹¹C-CFT PET/CT study can accurately reflect the changes of DAT in the striatum, and the amount of DAT is related to the severity of the ischemic insult in a newborn piglet model of HI. (authors)