Global cortical atrophy scale
The global cortical atrophy (GCA) scale, also known as the Pasquier scale, is a qualitative rating system developed to assess cerebral atrophy, especially in the context of neurodegenerative diseases. It evaluates atrophy in 13 brain regions assessed separately in each hemisphere and resulting in a final score that is the sum of all regions 1.
The thirteen brain regions evaluated are:
- sulcal dilatation
- frontal (right and left)
- parieto-occipital (right and left)
- temporal (right and left)
- ventricular dilatation
- frontal (right and left)
- parieto-occipital (right and left)
- temporal (right and left)
- third ventricle
The score for each region can range from 0 to 3 accordingly to the following criteria:
- 0: normal volume/no ventricular enlargement
- 1: opening of sulci/mild ventricular enlargement
- 2: volume loss of gyri/moderate ventricular enlargement
- 3: 'knife blade' atrophy/severe ventricular enlargement
After the original publication, other studies have proposed a simplification of the Pasquier scale to provide a more general impression of atrophy throughout the brain, making it easier and more accepted 2. It is important to note that this tool is only a component part of a larger diagnostic assessment in neurodegenerative diseases (for a broad discussion, please refer on neurodegenerative MRI brain (an approach)).
History and etymology
The scale was described in 1997 by Florence Pasquier, a French neurologist, as a tool to quantify atrophy in patients after stroke 1.
Related Radiopaedia articles
Neurodegenerative diseases
Neurodegenerative diseases are legion and their classification just as protean. A useful approach is to divide them according to underlying pathological process, although even using this schema, there is much overlap and thus resulting confusion.
-
neurodegenerative MRI brain (an approach)
- measurements and ratios
- midbrain to pons area ratio (for PSP)
- Magnetic Resonance Parkinsonism Index (MRPI) (for PSP)
- frontal horn width to intercaudate distance ratio (FH/CC) (for Huntington disease)
- intercaudate distance to inner table width ratio (CC/IT) (for Huntington disease)
- signs
- hummingbird sign (of PSP)
- Mickey Mouse sign (of PSP)
- morning glory sign (of PSP)
- hot cross bun sign (of MSA-C)
- hockey stick sign (of Creutzfeldt-Jakob disease)
- pulvinar sign (of Creutzfeldt-Jakob disease)
- scoring systems
- measurements and ratios
-
neurodegenerative diseases
-
synucleinopathies
- diseases with Lewy bodies
-
multiple systemic atrophy (MSA)
- Shy-Drager syndrome
- MSA-P (striatonigral degeneration)
- olivopontocerebellar atrophy (MSA-C)
-
tauopathies
-
Alzheimer disease
- typical/classical Alzheimer disease
- variant (e.g. posterior cortical atrophy)
- chronic traumatic encephalopathy (CTE)
- corticobasal degeneration
- frontotemporal lobar degeneration (FTLD) (not all are tau)
- Pick disease
- progressive supranuclear palsy (PSP)
-
Alzheimer disease
- amyloidoses
- TDP-43 proteinopathies
- spinocerebellar ataxias
- Huntington disease
- hereditary spastic paraplegia
- clinically unclassifiable parkinsonism (CUP)
- Unverricht-Lundborg disease
-
prion diseases (not always included as neurodegenerative)
- Creutzfeldt-Jakob disease (sporadic, variant, familial, and iatrogenic)
- fatal familial insomnia
- Gerstmann-Straussler-Scheinker disease
- kuru
- variably protease-sensitive prionopathy
-
synucleinopathies