Posttreatment CT and MR Imaging in Head and neck ca.pptx

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1. Posttreatment CT and MR Imaging in Head and Neck Cancer Dr. Anjali Deshmukh Junior resident Department of Radiology

2. In patients with head and neck cancer, posttreatment imaging can be complicated and difficult to interpret because of the complexity of the surgical procedures performed and the postirradiation changes. The posttreatment imaging findings in patients with head and neck cancer can be divided into four groups: Altered anatomy secondary to surgical reconstruction Tumor recurrence Potential postsurgical complications Possible postirradiation changes.

3. Imaging findings of early reactions to radiation therapy are- Thickening of the skin and platysma R eticulation of the subcutaneous fat , edema and fluid in the retropharyngeal space I ncreased enhancement of the major salivary glands T hickening and increased enhancement of the pharyngeal walls T hickening of the laryngeal structures

4. Late reactions to radiation therapy are- Atrophy of the salivary glands T hickening of the pharyngeal constrictor muscle, platysma, and skin

5. Normal appearance after neck dissection for right cervical lymph node metastases

6. Serous retention

7. Fistula and abscess after radiation and surgery

8. Tumor Recurrence The most common locations for tumor recurrence are in the operative bed and at the margins of the surgical site. Tumor recurrence is identified as a slightly expansile lesion in the operative bed or as progressive thickening of soft tissues deep to the flap. CT demonstrates recurrence as an infiltrating slightly hyperattenuating mass with enhancement, with or without bone destruction. MR imaging demonstrates tumor recurrence as an infiltrative mass with inter- mediate T1-weighted signal intensity, intermediate to high T2-weighted signal intensity, and enhancement.

9. DD- vascuralized scar Retraction and decreased signal intensity on T2-weighted MR images at the follow-up examination are suggestive of fibrosis. In addition, diffusion weighted MR imaging has been reported to be a useful tool to differentiate tumor recurrence from normal postoperative changes and fibrosis.

10. C ervical lymph node metastases occur in predictable patterns. Carcinomas in the oral cavity frequently -level I, II, and III nodes. Oropharynx and supraglottic larynx -level II, III, and IV nodes . Carcinomas involving the nasopharynx, hypopharynx and the base of tongue - level II, III, IV, and V nodes T hyroid cancer- level III, IV, and VI nodes are commonly involved. Bilateral lymph node metastases are frequently seen for carcinomas of the nasopharynx, oropharynx, base of the tongue, and supraglottic larynx.

11. Mucosal necrosis M ay cause substantial pain and interferes with the patient’s ability to chew and swallow. The risk - greatest during the first 6–12 months after radiation therapy. Imaging - L ack of mucosal enhancement, with or without ulceration . - Pockets of gas identified adjacent to the lesion should raise suspicion for tissue necrosis.

12. Osseous complications Osteoradionecrosis- c ondition in which irradiated bone becomes devitalized and exposed through the overlying skin or mucosa, persisting without healing for at least 3 months. Sites- Skull base, temporal bone, mandible, maxilla, and hyoid bone. Of these, the mandible is the most common site of osteoradionecrosis because of its superficial location and relatively poor blood supply.

13. C hronic focal pain, swelling, and facial deformation. Although these imaging findings mimic those of tumor recurrence, the presence of an associated soft-tissue mass favors a diagnosis of tumor recurrence. The identification of cortical defects remote from the primary tumor site can also help in the diagnosis of osteoradionecros is. CT - focal lytic area with cortical destruction, sequestra formation, and loss of the trabeculation pattern MR- images of osteoradionecrosis show abnormal signal intensity in the bone marrow, with cortical destruction.

14. F ocal lytic area with cortical destruction and a pathologic fracture in the right mandibular ramus

15. Vascular complications Accelerated atherosclerosis and thrombosis of the internal jugular vein or carotid artery, Formation of a pseudoaneurysm of the internal carotid artery (rare)

16. Radiation Induced lung disease Radiation therapy for patients with head and neck cancer often includes the apical aspect of the thorax, to encompass the supraclavicular nodes and level IV nodal areas. Radiation pneumonitis (1–3 months after completion of radiation therapy, Radiation fibrosis (occurs within 6–12 months after radiation therapy and can progress for as long as 2 years before stability occur) Dyspnea, cough and fever.

17. Radiation Pneumonitis G round-glass attenuation or consolidation or both

18. Radiation fibrosis well defined area of volume loss scarring and traction bronchiectasis

19. Radiation induced brain necrosis Ring enhancing mass with variable edema

20. Radiation induced neoplasm The diagnostic criteria of postirradiation osteosarcoma include a lesion centered in irradiated bone without a primary malignant osteoblastic lesion, arising after a latency period of at least 3 years after the completion of radiation therapy . Meningioma, sarcoma (osteosarcoma, malignant fibrous histiocytoma), osteochondroma, schwannoma, osteoblastoma, squamous cell carcinoma, and lymphoma

21. Posttreatment Surveillance Imaging I deally the baseline imaging examination should be performed at the time when most postoperative changes have resolved and when tumor recurrence rarely occurs. Between 4 and 8 weeks after treatment. Surveillance, including clinical examination is frequently performed every 3–4 months in the first 2 years, every 4–6 months in years 2–5, and then annually thereafter. Surveillance protocol should include not only the diagnosis of tumor recurrence, but the possible identification of a second primary malignancy, such as lung cancer and other upper aerodigestive tract cancers.

22. Thank you