On imaging reports, mastoiditis can span clinical entities ranging from a benign incidental finding of mastoid effusion to fulminant coalescent mastoiditis. This range of entities has different levels of medical urgency and appropriate therapy. Differentiating among possibilities requires consideration of the entire clinical picture. A review of the images themselves, often in conversation with the interpreting radiologist or otolaryngology consultant, is helpful in resolving the ambiguity created when encountering the nonspecific term mastoiditis.