Google Spreadsheets Regex Case Insensitive（Regexreplace）

I'm trying to create a case insensitive regex query in Google Spreadsheets with the regexreplace function. Is that possible? I've tried the \i flag and got a #REF error saying the expression was invalid: =regexreplace("Test","t\i","") gives an error when I would hope to get "es" as the final result.I'm trying to create a case insensitive regex q