How to persist #sections document introspection variable in Power BI

This response might be a bit late. I ended up creating a "lookup" table in PQ with the parameter info, similar to the below. Not ideal as it will not dynamically add/remove parameters when the list changes, but at least it refreshes the values when they are updated and they can be used in DAX. 

let Source = 

Table.FromRecords({
  [Name="Parameter name", Value = #"Parameter Name"], //reference to the parameter,
  [Name="another Parameter name", Value = #"Another Parameter Name"] //reference to the parameter
  })
in
    Source

And then adding a DAX measure, e.g. 

File Content Value = 
var parameterName = "Parameter Name" 
return
LOOKUPVALUE(<tablename>[Value],<tablename>[Name],parameterName)

 Replace <tablename> with the name of the query/table you're referencing.

Also documented here: https://www.linkedin.com/pulse/using-parameters-powerbi-ferry-van-der-vorst-6p1ee/