Introduction: Principles of echo shifting with a train of observations (PRESTO) sequence has long echo time which emphasizes the effect of T2* relaxation time and contribute to its high sensitivity to the susceptibility change. The aim of our study was to evaluate the ability of 3D-PRESTO sequence in detecting putaminal hypointensity in patients with parkinsonian variant of multiple system atrophy (MSA-P) and in discriminating between MSA-P and Parkinson's disease (PD).
Methods: The signal intensity of the putamen and localization of abnormality were evaluated on 3D-PRESTO, T2*-weighted (T2*W), and T2-weighted (T2W) sequences in ten patients with MSA-P, 14 with PD, and ten controls. The putaminal signal intensity was assessed in all sequences and graded relative to the palladium. Atrophy of the putamen and posterolateral hyperintensity rim on T2W sequence were also evaluated in MSA-P patients.
Results: Putaminal hypointensity was more often seen in MSA-P than PD and controls on 3D-PRESTO sequence (p = 0.002) as well as on T2*W sequence (p = 0.003). 3D-PRESTO sequence could reveal lower intensity better than T2*W sequence in four of ten MSA-P cases. Hemi- or bilateral putaminal hypointensity, atrophy, and posterolateral hyperintensity rim were recognized in 90%, 70%, and 70% of ten MSA-P cases, respectively. Three cases revealed hypointensity on 3D-PRESTO sequence without posterolateral hyperintensity rim. Putaminal signal changes occurred in the posterolateral part with a striking lateral to medial gradient in all nine cases with putaminal hypointensity (nine out of nine, 100%).
Conclusions: 3D-PRESTO sequence appears to be useful for depicting putaminal hypointensity in MSA-P patients and in differentiating MSA-P from PD.