Powershell Running MSTest.exe with multiple tests - how to output only failed tests?

I have a string of all the tests I want to run with MSTest.exe, and I want to output only if there are errors, failed tests and perhaps warnings.

A part of the Powershell script (the ... stands for many more /testcontainer:Test....dll).

# sb is a string builder
$sb = "C:\...\MSTest.exe" /testcontainer:Test....dll ...  /testcontainer:Test...dll 

cmd.exe /c $sb.ToString()

Currently it outputs everything (A lot of "Test passed" for example - which I don't need to see).

I tried looking in the MSTest command line options docs but couldn't find any.

How can I output only the important stuff?