ABSTRACT
In the present study 20 patients with the clinical diagnosis of idiopathic parkinson disease are included. All patients were subjected to [1] full clinical examination and MRI study of the brain with a special focus on the mid-brain and the basal ganglia. Based on the duration of the parkinsonian symptomatology and the clinical response to levodopa treatment, patients were classified into two main groups. Group [A] is characterized by short duration of the parkinsonian symptomatology and a good sustained response to levodopa treatment, while group [B] was characterized by a longer duration of the parkinsonian symptomatology and a fluctuant response to levodopa treatment. MRI demonstrated important structural changes at the level of the substantia nigra and the red nucleus in both groups, while structural changes at the level of the basal ganglia [putaminal hypointensity on the T2 weighted images] were demonstrated only in group [B] patients. The significance of the MRI findings, their probable aetiology and pathogenesis, their value in explaining the pattern of clinical levodopa responsiveness and their implications in the management of parkinson disease will be discussed