MRI brainstem studies – 2 main PSP types and PD

The two main types of PSP — Richardson’s syndrome and PSP-parkinsonism — are very different. I remember being in support group meetings early on, when the evidence of these two types wasn’t yet published, and wondering if the person sitting next to me was dealing with PSP at all! (“How can your parent not have cognitive impairment?”)

It’s great to have studies now that look in detail at the pathologic, radiologic, and clinical differences in these two main types. RS is easier to diagnose because it’s very different from Parkinson’s Disease or Alzheimer’s Disease; it is called “classic PSP.” PSP-P is much harder to diagnose accurately because it looks so much like Parkinson’s Disease or Multiple System Atrophy.

An Italian study was published this week that looks at MRI measurements of brainstem structures in RS (10 patients), PSP-P (10 patients), and Parkinson’s Disease (25 patients). Using certain measurements, MRIs could be used to differentiate RS from PD but the accuracy of differentiating PSP-P from PD was not as high. The authors say that the such MRI measurements “can, at least partially, contribute to the identification of patients with PSPP versus those with PD.”

The search continues for something to differentiate PSP-Parkinsonism from Parkinson’s Disease and MSA….

I’ve copied the abstract below.


Movement Disorders. 2010 Dec 15. [Epub ahead of print]

MRI measurements of brainstem structures in patients with Richardson’s syndrome, progressive supranuclear palsy-parkinsonism, and Parkinson’s disease.

Longoni G, Agosta F, Kostic VS, Stojkovic T, Pagani E, Stošic-Opincal T, Filippi M.
Neuroimaging Research Unit, Institute of Experimental Neurology, Division of Neuroscience, Scientific Institute and University Ospedale San Raffaele, Milan, Italy.

We investigated the diagnostic accuracy of brainstem MRI measurements in patients with different progressive supranuclear palsy (PSP) syndromes and Parkinson’s disease (PD).

Using 3D T1-weighted images, midbrain, and pons areas, as well as superior (SCP) and middle cerebellar peduncle (MCP) widths were measured in 10 patients with Richardson’s syndrome (PSP-RS), 10 patients with PSP-parkinsonism (PSP-P), 25 patients with PD, and 24 healthy controls.

The ratio between pons and midbrain areas (pons/midbrain), that between MCP and SCP widths (MCP/SCP), and the MR parkinsonism index ([pons/midbrain]*[MCP/SCP]) were calculated.

The pons/midbrain and the MR parkinsonism index allowed to differentiate PSP-RS from PD with high sensitivity (90%, 100%), specificity (96%, 92%), and accuracy (94%, 97%).

Only the pons/midbrain was found to distinguish PSP-P from PD, but with a lower diagnostic accuracy (sensitivity = 60%, specificity = 96%, accuracy = 86%).

Compared to PSP-RS, PSP-P experience a relatively less severe involvement of infratentorial brain.

The pons/midbrain looks as a promising measure in the differentiation of individual PSP-P from PD patients.

© 2010 Movement Disorder Society.

PubMed ID#: 21162106 (see for this abstract only)