Pigmented neurons in the substantia nigra pars compacta (SNc) and locus coeruleus (LC) show decreased numbers differentially in Parkinson's disease (PD) and multiple system atrophy (MSA). Recent reports have described that fast spin-echo T1-weighted magnetic resonance imaging (MRI) by a 3-tesla machine can visualize neuromelanin-related contrast of the noradrenergic and dopaminergic neurons respectively in the LC and the SNc. Using neuromelanin MRI at 3 T, we investigated possible alterations of these catecholaminergic neurons in 32 PD and 9 MSA patients, and compared the results with those of 23 normal volunteers. The contrast ratio of the LC and SNc was decreased in MSA and PD patients, most prominently in the LC in MSA patients. The contrast ratio of the SNc was correlated with the Hoehn-Yahr stage of PD and the severity of neuroradiological abnormalities in MSA. These results indicate a potential diagnostic value of neuromelanin MRI to distinguish MSA patients from normal and PD patients.

Some patients with Parkinson's disease (PD) develop peri-lead brain edema after deep brain stimulation (DBS) surgery. The influence of edema on neurological function is not well characterized. We investigated the relationship of brain edema after DBS surgery with motor and cognitive function. Thirteen patients with PD (6 males and 7 females; mean age: 61.2 years) who underwent bilateral subthalamic nucleus (STN) DBS surgery were included. All patients underwent magnetic resonance imaging (MRI) examination on day 6 post-DBS surgery. The volume of edema was measured either in the frontal white matter or STN on fluid attenuated inversion recovery (FLAIR) images. We examined the relationship between these volumes and changes in cognitive and motor function. Patients were divided into those with frontal subcortical edema (FE) ≥3,000 mm³ (FE + group; n = 7) and <3,000 mm³ (FE–group; n = 6). In the FE + group, the postoperative Mini-Mental State Examination score worsened by 2.4 points after one week compared with that immediately before surgery, while that in the FE-group worsened only by 0.2 points (p = 0.038). On comparing patients with peri-STN edema (SE) ≥1,000 mm³ (SE + group; n = 3) and those with SE < 1,000 mm³ (SE-group; n = 10) showed that frequency of DBS tuning in the early postoperative period of the SE + group was lesser than that in the SE-group. Development of FE after DBS surgery was related to transient cognitive decline. On the other hand, SE seemed associated with altered motor function and reduces the requirement for tuning in the initial period after DBS implantation.