Fig. 3. 60-year-old male with squamous cell carcinoma of right pyriform sinus (T3N1M0) after definitive concurrent chemoradiation therapy.

Pretreatment (A, B) and post treatment (C, D) axial T2-weighted images (T2WIs) and contrast-enhanced fat-suppressed T1-weighted images (CE FS T1WIs) demonstrate homogeneously enhanced superior cervical sympathetic ganglia (CSG, thin arrows on A-D) on either side lateral to longus capitis muscle (arrowheads on A) and posterior to internal carotid artery (empty arrows on A). Note that there is typical intraganglionic hypointensity at center of superior CSGs both on T2WI and CE FS T1WI. Superior CSGs become enlarged in anterior to posterior dimensions along with diffuse radiation-induced change in retropharyngeal space, pharyngeal wall, and bilateral cervical level II.