What type of CT examination has been performed ? What is the preliminary diagnosis ?

A 47-year-old woman who had pelvic surgery 5 days earlier presented with sudden onset shortness
of breath and bilateral chest pain. Physical examination showed she was in respiratory distress
and tachycardic. Examination of the chest was essentially normal. Laboratory investigations
showed hypoxia and hypocapnia. A preliminary CXR was unremarkable and a CT examination
was performed