Imaging Hodgkin and non-Hodgkin lymphoma in the head and neck.

Hodgkin (HL) and non-Hodgkin lymphoma (NHL) involving the head and neck have many overlapping imaging features. Definitive diagnosis depends on histology, but imaging trends may help distinguish lymphoma from other common pathologic entities in the head and neck. CT is useful for staging and assessing bony involvement, whereas MR imaging is performed for soft tissue detail in extranodal disease, especially when there is transpatial disease or intracranial or intraspinal extension. Positron emission tomography has become an important part of staging and surveillance imaging and is particularly useful to distinguish posttreatment fibrosis and residual tumor.