Clinical findings and imaging features of 67 nasopharyngeal carcinoma patients with postradiation nasopharyngeal necrosis

Abstract

Postradiation nasopharyngeal necrosis is an important late effect of radiotherapy that affects prognosis in patients with nasopharyngeal carcinoma. In the present study, we reviewed the clinical and imaging features of 67 patients with pathologically diagnosed postradiation nasopharyngeal necrosis who were treated at Sun Yat-sen University Cancer Center between June 2006 and January 2010. Their clinical manifestations, endoscopic findings, and imaging features were analyzed. Early nasopharyngeal necrosis was limited to a local site in the nasopharyngeal region, and the tissue defect was not obvious, whereas deep parapharyngeal ulcer or signs of osteoradionecrosis in the basilar region was observed in serious cases. Those with osteoradionecrosis and/or exposed carotid artery had a high mortality. In conclusion, Postradiation nasopharyngeal necrosis has characteristic magnetic resonance imaging appearances, which associate well with clinical findings, but pathologic examination is essential to make the diagnosis.

Diffusion-weighted and PET/MR Imaging after Radiation Therapy for Malignant Head and Neck Tumors

“…Similar to the imaging appearances of most radiation therapy-induced tissue alterations, MR imaging features of soft-tissue necrosis include higher T2 signal intensity and higher ADC values than those of recurrent head and neck SCC (15,31,32,60). After administration of gadolinium contrast agent, necrotic areas show no enhancement (72). Focal FDG uptake around the necrotic area is common because of coexisting inflammation with granulation tissue, and measured SUVs can be high.…”

“…Transmural necrosis of the vessel wall can lead to pseudoaneurysm formation, which harbors risk for carotid rupture. Carotid rupture can occur as a consequence of radiation therapy alone, or it may be precipitated by softtissue necrosis, associated infection, and exposure to saliva (72,73). Stenosis of the carotid arteries is the most common manifestation of radiation therapy-induced arteriopathy in the head and neck.…”

“…MR imaging findings are subtle, and the normally enhancing mucosal line appears discontinuous (72). In more advanced stages, soft-tissue ulcerations are seen at CT and MR imaging as large, well-delineated, "punchedout" defects (Fig 7, Fig E1 [online]) and may lack the characteristic enhancing mucosal layer (32,(71)(72)(73). Tiny air-filled pockets near the ulcerated area and fistula formation are common (13,71,72).…”

“…In more advanced stages, soft-tissue ulcerations are seen at CT and MR imaging as large, well-delineated, "punchedout" defects (Fig 7, Fig E1 [online]) and may lack the characteristic enhancing mucosal layer (32,(71)(72)(73). Tiny air-filled pockets near the ulcerated area and fistula formation are common (13,71,72). Extensive soft-tissue necrosis can extend into the skull base, parapharyngeal space, and carotid space and may lead to life-threatening carotid rupture (73).…”

“…Radiation therapy-induced soft-tissue necrosis is typically seen at the initial tumor site. It is caused by vascular and lymphatic vessel damage that leads to formation of hypoxic hypovascular tissue, and this "fragile" tissue is prone to necrosis and subsequent infection (71)(72)(73). Soft-tissue necrosis in the head and neck is typically associated with laryngeal or pharyngeal ulcer and occasionally with fistula formation (13,71) (Fig 7).…”