DECREASED MYOCARDIAL I-123 MIBG UPTAKE IN PARKINSONS-DISEASE

We studied myocardial I-123-metaiodobenzylguanidine (MIBG) accumulatio n in 12 patients with Parkinson's disease (PD). MIBG is an analog of n orepinephrine (NE) and a tracer for sympathetic neuron integrity and f unction. MIBG uptake of the myocardium was significantly lower in PD t han in controls. The heart to mediastinum ratio (H/M) was calculated b y using the average count per pixel for the heart and mediastinum. In PD, H/M was lower than in controls (P<0.0001), while the washout ratio of the heart was higher (P<0.001). A decrease in myocardial accumulat ion of MIBG was observed in the early stage of PD, This suggests that the measurement of MIBG may help the diagnosis of early PD, and the ca usative factor underlying in PD may be operating the NE neuron as well as dopamine neuron.