Dopamine transporter distribution in patients with Parkinson disease of different stages detected using single-photon emission computed tomography brain imaging

Abstract

Background Literatures have reported that the density changes of dopamine transporter is negatively correlated with the severity degree and grading of disease condition of Parkinson disease (PD). However, the distribution of dopamine transporter in each nucleus of corpora striatum at each period is still unclear. Objective To observe the radioactive uptake distribution of dopamine transporter in bilateral corpora striata of patients with different stages of PD using single photon emission computed tomography (SPECT), and make a comparison with healthy controls. Design Case-control analysis. Setting Department of Imageology, Second Hospital Affiliated to Guangzhou University of Chinese Medicine. Participants Thirty patients with PD admitted to Second Hospital Affiliated to Guangzhou University of Traditional Chinese Medicine between January and December 2005 were recruited. The involved patients, 19 male and 11 female, were aged from 36 to 80 years and with disease course of 2.5 months to 10 years. They all met the clinical diagnosis criteria of Britain Parkinson's disease Association Think Tank; Following Hoehn-Yahr grading: grade I: unilateral morbidity; grade II: bilateral morbidity, but without balance disorder; grade III: bilateral morbidity, accompanied with early posture balance disorder; grade IV: severe morbidity, needs more help; grade V: without help, only in bed or wheelchair. There were 11 patients with mild PD (grade I–II), 9 patients with moderate PD (grade III) and 10 patients with advanced PD (grade IV–V). Meanwhile, 6 healthy persons were selected as normal controls. Informed consents were obtained from all the subjects. Methods Twenty-four hours after withdrawal of PD drugs, 30 patients with PD and 6 healthy controls took kalium perchloricum 400 mg orally. After lying down for 30 minutes, all the subjects were intravenously injected with 740 MBq 99Tc m-TRODAT-1 (Jiangsu Institute of Atomic Medicine, Batch No. 20040310) at elbow part. Following injection, image was collected using scanner for single photon emission computed tomography (ADAC Company, USA). Matrix was 64×64, each detecting head revolved 180°, 1 frame/60 s. Sixty-four frames were collected with double detecting heads, 50 K/frame. Faultages with clearest image of corpora striatum were selected. Regions of interest (ROI) of caudate nucleus, anterior and posterior putamen and thalamic region in bilateral corpora striata were radioactively counted, and mean value of radioactive counting of ROI was used as the mean value of pixel in each region of bilateral corpora striata. Main outcome measures Comparison of radioactive uptake in each region of brain between healthy persons and patients with PD. Results Thirty patients with PD and six healthy persons who received body examination participated in the final result. Comparison of radioactive uptake in each region between healthy persons and patients with PD: ▪In the healthy persons, high-density radioactive uptake was found in bilateral corpora striata; Structures of caudate nucleus, anterior and posterior putamen, and thalamus were clear with eudipleural radioactive distribution, and the background of peripheral brain tissue was very low. ▪Radioactive intakes in opposite anterior and posterior putamen of patients with mild PD were significantly inferior to those in homolateral ones(70.45±3.35,87.64±2.65, t =15.82, P < 0.05). Structures of bilateral caudate nucleus and thalamus were clear with eudipleural radioactive distribution ( P > 0.05). ▪ Radioactive intakes in anterior and posterior putamen and thalamus of patients with moderate PD were significantly reduced as compared with healthy persons. There were significant differences in mean radioactive counting of ROI between patients with PD and healthy persons ( t =5.20, P < 0.05; t =3.95, P < 0.05); The structure of opposite caudate nucleus was not very clear, radioactive distribution of opposite caudate nucleus was significantly reduced as compared with homolateral one (81.11±4.25,104.56±3.64, t = 14.65, P < 0.05). ▪As for patients with advanced PD, the structure of bilateral corpora striata was not clear, radioactive intake was significantly reduced and peripheral background was heightened, even higher than the distribution of the whole corpora striatum. Conclusion SPECT DAT imaging of brain can show the distribution of radioactive uptake in each region of bilateral corpora striata of patients with different stages of PD, which is helpful to diagnose and evaluate the severity of PD.