Treatment monitoring of paranasal tumors is crucial, given the high rate of local and regional relapses that impairs the overall prognosis of patients. Magnetic resonance imaging (MRI) is the technique of choice to detect changes in the submucosa and deep spaces of the suprahyoid neck, inaccessible at clinical and endoscopic assessment. Correct interpretation of MRI requires detailed knowledge of the treatment applied and of the changes treatments are supposed to produce on macroscopic anatomy and tissue signals. Once such background of information is obtained, detection of recurrences is a less challenging task.