An example of airway infection / pharyngitis complicated with spread into the deep neck spaces, namely into the retropharyngeal space which can act as conduit of infection to spread into the mediastinum. This florid example also shows inflammatory change in the anterior cervical tissues which is a common and easier route of infection.

Our center uses a 100 second delay for CT necks.  However, to help differentiate between phlegmon and abscess either a repeat examination after a few minutes or diffusion MRI sequences can be useful.