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.