Study Patients

The study population was obtained from a historical cohort of 97 consecutive patients who were diagnosed with head and neck cancer by pathology examination and undergone definite treatment including surgery, radiation therapy, or chemoradiation therapy at Asan Medical Center, a 2700-bed academic tertiary referral hospital in Seoul, Korea, between March, 2013 and July, 2014 (Figure ​(Figure1).1). Of these, 52 patients had a radiologically measureable enhancing mass (>1 cm) or asymmetric soft-tissue thickening at primary site on posttreatment follow-up MRI including DCE-MRI.²² Patients were excluded if they had any of the following criteria: poor image quality due to artifact or no final diagnosis (local recurrence or posttreatment change) either by histology or clinicoradiologic follow-up. Local recurrence was defined as histological (biopsy or surgery) confirmation of a tumor or an increase in the size of the mass. We defined increase in size as at least 20% increase in maximum diameter of enhancing lesion mass at the primary site on follow-up clinical or imaging examinations. Posttreatment change was defined as the absence of any new mass or increase in size of any preexisting enhancing lesion at the primary site during a follow-up period of at least 1 year or histological (biopsy or surgery) confirmation of posttreatment change. Finally, 24 patients were included in this study.

Patients flow diagram.