Purpose: The purpose of this study was to determine the clinical value of applying Tc-99m TRODAT-1 single photon emission computed tomography (SPECT) of the dopamine transporter to evaluate disease severity in young patients with symptomatic or asymptomatic Wilson disease (WD).
Materials and methods: The evaluation of Tc-99m TRODAT-1 SPECT was performed in 18 patients with symptomatic WD, 13 patients with asymptomatic WD, and, as controls, 12 normal volunteers matched for age and gender. The neurologic symptoms of symptomatic patients were evaluated by an experienced neurologist. The ratios of specific striatal Tc-99m TRODAT-1 binding [with the cerebellum (CB) as the reference region] were calculated as striatum (ST)/CB and compared among the 3 groups. Using correlation analysis, the ratios for the WD patients were compared with clinical data on the severity of neurologic symptoms.
Results: Significant differences of ST/CB ratios were found among the 3 groups (Sym vs. Nor, P = 0.000; Asym vs. Nor, P = 0.036; Sym vs. Asym, P = 0.011, respectively). In 23 patients (18 with symptomatic WD, 5 with asymptomatic WD), the posterior putamina showed more remarkable deformation and decreased radiotracer uptake. The ST/CB ratios correlated negatively with the severity of neurologic symptoms (r = -0.80, P < 0.01).
Conclusions: The decreased striatal Tc-99m TRODAT-1 uptake found in young WD patients, including symptomatic WD and some asymptomatic WD, as detected with SPECT, seems to indicate presynaptic damage of the dopaminergic nerve terminals. The decrease in radiotracer uptake was more prominent in the posterior putamina than in the caudate heads. The Tc-99m TRODAT-1 SPECT method can be used effectively for evaluating disease severity in WD.