Hex formatting within powershell object

I'm trying to get hex output. This code:

    get-wmiobject -class "Win32_LoggedOnUser" -namespace "root\CIMV2" -Property * | `
      Select @{Name="Antecedent";Expression={$_.Antecedent.Split('=').replace("`"","")[2]}}, `
      @{Name="Dependent";Expression={$_.Dependent.Split("`"")[1]}}

Will generate two columns, login name and logonID as follows:

Antecedent      Dependent
----------      ----------
SYSTEM          999      
LOCAL SERVICE   997      
NETWORK SERVICE 996      
<user>          347528   
<user>          6842494  
<user>          46198354 
<user>          46171169 
DWM-2           223575   
DWM-2           223551  

Event Viewer uses the hex representation of the logonID, for example 'SYSTEM 'would be represented by 0x3e7 vs 999, or in PowerShell

 ps> '{0:x}' -f 999

I'm trying to match up with that.

I'm trying to do something along these lines:

    get-wmiobject -class "Win32_LoggedOnUser" -namespace "root\CIMV2" -Property * | `
      Select @{Name="Antecedent";Expression={$_.Antecedent.Split('=').replace("`"","")[2]}}, `
      @{Name="Dependent";Expression={'{0:x}' -f $_.Dependent.Split("`"")[1]}}

But no luck so far.