A full radiology report typically contains several sections, similar to a progress note. The "HISTORY" section discusses the medical history and possibly indications for the imaging. Here, r/o means neither "has been ruled out" nor "should be ruled out in the future". It means the patient has such and such a history and this imaging test was done in order ...
URTI is a common abbreviation for upper respiratoty tract infection and
GE for gastroenteritis, which refers to infection of the stomach and intestine, which is usually associated with diarrhea.
An example of the usage of URTI and GE in a PubMed article. This source should not be used to make any conclusions about the cause.
Minim (unit): Part of the Apothecary system. It is rarely used anymore(some countries and areas still use the apothecary system) and is a alternative to the drop(which was formerly the smallest unit of the apothecary system).
The minim (abbreviated min, ♏ or Mx, a symbol for minim in the
apothecaries' system.svg) is a unit of volume in both the imperial ...
I finally found the symbol on page 5 of the quick reference guide (http://nippyventilator.com/wp-content/uploads/2015/07/NIPPY-Junior-Quick-Reference-Guide.pdf) for the ventilator. It is just an indicator that the disconnect alarm has been set to low sensitivity.