C# - Get Local User By SID?

I want to get a local windows user by SID: I found this code

[ADSI]("WinNT://$Env:Computername/<SID=S-1-5-18>")

[URL]

I deduced from it, I could do it in (VB) .NET with this:

Dim strURL As String = "WinNT://" + strComputerName + "/<SID=" + strSID + ">"
Dim de As DirectoryServices.DirectoryEntry = New DirectoryServices.DirectoryEntry(strURL)
de.Properties("whatever").Value.ToString()

However, this doesn't work.Anybody knows how I can do this WITHOUT looping over all users (which requires to convert from byte[] to string first, and then compare [case insensitive] a lot of strings, which makes it slow).