The putaminal abnormalities on 3.0T magnetic resonance imaging: can they separate parkinsonism-predominant multiple system atrophy from Parkinson's disease?

Background: The putaminal abnormalities detected on 1.5T magnetic resonance imaging (MRI), such as putaminal atrophy, slit-like hyperintense rim, and hypointensity in the putamen on T2-weighted (T2W) imaging are important signs on differentiating multiple system atrophy with parkinsonism (MSA-P) from Parkinson's disease (PD). However, the putaminal abnormalities may have different manifestations on 3.0T from those on 1.5 T. Purpose: To investigate the diagnostic value of putaminal abnormalities on 3.0T MRI for differentiating MSA-P from PD. Material and Methods: The study included a MSA-P group (9 men, 9 women), a PD group (12 men, 14 women), and a control group (11 men, 13 women). All subjects were examined with 3.0T MRI using the conventional protocol. Putaminal atrophy, T2-hypointensity in the dorsolateral putamenat, and a slit-like hyperintense rim on the lateral putamen were evaluated in each subject. Results: There were no significant differences in the slit-like hyperintense rim (P=0.782) or T2-hypointensity in the dorsolateral putamen (P=0.338) among the three groups. Bilateral putaminal atrophy was found in 44.4% (8 of 18) of the MSA-P patients, in only 7.7% (2 of 26) of the PD patients, and in none of the controls. The proportion of subjects with putaminal atrophy was significantly higher in the MAS-P group (P=0.008) and control group (P<0.001). The specificity and sensitivity of putaminal atrophy for distinguishing MSA-P from PD was 92.3% and 44.4%, respectively. Conclusion: The signal changes in the putamen on T2W imaging on 3.0T MRI, including slit-like hyperintense rim and putaminal hypointensity, are not specific signs for MSA-P. Putaminal atrophy is highly specific for differentiating MSA-P from PD and healthy controls, but its insufficient sensitivity limits its diagnostic value.