To keep your code robust and clean, use a single extension function, like this:
Public Module Extensions
<Extension()>
Public Function HasColumn(r As SqlDataReader, columnName As String) As Boolean
Return If(String.IsNullOrEmpty(columnName) OrElse r.FieldCount = 0, False, Enumerable.Range(0, r.FieldCount).Select(Function(i) r.GetName(i)).Contains(columnName, StringComparer.OrdinalIgnoreCase))
End Function
End Module