CT findings of osteoradionecrosis of the mandible

Transcription

1 CT findings of osteoradionecrosis of the mandible Poster No.: C-2569 Congress: ECR 2015 Type: Educational Exhibit Authors: J. Abreu e Silva, M. J. Magalhães, N. Costa, S. Ramos Alves, M. V. P. P. Gouvea; Porto/PT Keywords: DOI: Cancer, Education, CT, Bones /ecr2015/C-2569 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 12

2 Learning objectives Discuss the clinical features and the risk factors for osteoradionecrosis of the mandible. Describe the CT imaging features of mandibular osteoradionecrosis. Background Epidemiology and Risk Factors Osteoradionecrosis of the mandible (ORNM) is a serious complication of radiation therapy to the head and neck. The incidence of osteoradionecrosis varies widely in the literature ranging from 1% to 37%. Although ORNM occurs typically in the first three years after radiotherapy, patients probably remain at indefinite risk. The cause of osteoradionecrosis is radiation induced tissue damage. This damage is compounded by the fact that the mandible is essentially an end-artery system supplied by the inferior alveolar artery. Risks for osteoradionecrosis related to the radiation therapy include total radiation dose, photon energy, brachytherapy, field size, fractionation. Osteoradionecrosis is unlikely to occur if the radiation dose is below 60 Gy, delivered by standard fractions, but has a higher likelihood of occurrence if the dose is higher than Gy. Other risk factors include periodontitis, poor oral hygiene, alcohol and tobacco use, dental extractions, tumor size, location and stage, proximity of tumor to bone, and preirradiation bone surgery. Clinical presentation Page 2 of 12

3 Mandibular ORN is defined as an area of exposed bone through an opening in the overlying skin or mucosa, persisting as a non-healing region for a period of #3 months. This may present clinically with symptoms such as pain, swelling, malocclusion, dysphagia, orocutaneous fistula, trismus, or facial disfiguration. Findings and procedure details Because the diagnosis of ORNM can often essentially be based on clinical grounds, radiology is used for confirmation and evaluation of the extent of the bone involvement. The localization and extent of the bone destruction can be better evaluated with CT. Radiological investigations may also be useful to monitor the progress of conservative treatment, if instituted. Major diagnostic concern in a suspected case of ORN is to exclude tumour recurrence. Since a soft-tissue abnormality may be misinterpreted as tumor recurrence, correlation should be made with the typical osseous findings of mandibular osteoradionecrosis on CT scans. At CT, ORN may present as loss of osseous trabeculae in the spongiosa. It can manifest as osteolytic lesions and/or cortical erosions, involving the vestibular or lingual surface (Figures 1 to 4). When there is bicortical involvement in severe cases, pathological fractures occur (Figures 5 to 7). Bone sequestrum (Figure 8) may be seen as sclerotic fragments in the involved region of the mandible that are separated from the adjacent cortex. The osseous changes of ORN can be associated with adjacent soft-tissue changes. In fact, enhancement can occur in the adjacent soft tissues; however, identifying the aforementioned signs of osteoradionecrosis can lead to the correct diagnosis. Diffuse enhancement of the adjacent masseter and pterygoid muscles has been described. The main differential diagnosis is cancer invasion of the mandible (Figure 9), namely in cases of relapse. Page 3 of 12

4 Images for this section: Fig. 1: Axial CT images (bone window) demonstrates multiple lytic areas involving the mandible with associated cortical erosions (arrows in b), in a patient with oropharyngeal cancer post-rt. There is also subtle periosteal reaction in the posterior right horizontal ramus (in a). Features are suggestive of ORN. Page 4 of 12

5 Fig. 2: Axial CT image (bone window) of patient having received RT for tongue malignancy. It reveals unicortical erosion (arrow) involving the lingual cortex of the right horizontal ramus of the mandible with endomedular lytic lesion associated. Page 5 of 12

6 Fig. 3: Axial CT image (bone window) of a patient with a history of tongue cancer treated with surgery and RT shows morphostructural alteration of the left body and horizontal ramus of the mandible, mainly lytic, suggestive of ORN. Page 6 of 12

7 Fig. 5: Axial CT images (bone window) of a patient having received RT for pharyngolaryngeal malignancy. It shows advanced ORN changes in the mandible in the form of loss of osseous trabeculae in the spongiosa with lytic areas and cortical erosions, resulting in bone fragmentation with pathologic fractures. Page 7 of 12

8 Fig. 6: Axial CT images (bone window) of a patient having received RT for oral cavity malignancy reveals advanced ORN changes in the mandible. There is a diffuse altered bone structure in the form of mixed lytic sclerotic areas and associated bicortical erosions. A pathological fracture is seen in the left hemi-mandible in the transition body-horizontal ramus. Page 8 of 12

9 Fig. 4: Axial CT images of a patient with a right submandibular gland malignancy treated with surgery and RT. In the right submandibular area a cutaneous fistula is seen (arrow in a), RT treatment sequela. Deeply, the right ascending ramus of the mandible shows homogeneous periosteal thickening and vestibular osteolytic lesions (arrows in c and b, respectively), in relation to ORN. Fig. 8: Coronal (a) and axial (b) CT images (bone window) showing sequestrum (arrow) in the form of a bone fragment separated from the involved cortex by an erosion. Page 9 of 12

10 Fig. 7: CT axial imaging (bone window) of a patient with a previous mouth floor carcinoma submitted to surgery with parcial right mandibulectomy and reconstruction with bone graft and also to RT. Note the ORN findings in the left native hemimandible. Page 10 of 12

11 Fig. 9: Axial CT images of a patient with previous tongue cancer, with a second neoplasia in the gengiva of the left inferior alveolar ridge, with direct invasion of the mandible. Page 11 of 12

12 Conclusion ORN is a dreaded complication of head and neck RT. CT imaging plays an important role in the diagnosis of mandibular osteoradionecrosis as well as in the exclusion of local tumor recurrence. Personal information References 1. Debnam JM. Imaging of the Head and Neck following Radiation Treatment. Patholog Res Int. 2011;2011: Chrcanovic, B., Reher, P., Sousa, A. et al. Osteoradionecrosis of the jaws-a current overview-part 1: physiopathology and risk and predisposing factors. Oral Maxillofac Surg. 2010; 14: Offiah C, Hall E. Post-treatment imaging appearances in head and neck cancer patients. Clin Radiol Jan;66(1): Hermans R. Posttreatment imaging in head and neck cancer. Eur J Radiol Jun;66(3): Hermans R; Fossion E; Ioannides C; Van den Bogaert W; Gherkiere J; Baert AL. CT findings in osteoradionecrosis of the mandible. Skeletal Radiol 1996; 25: Becker M; Schroth G; Zbären P; Delavelle J; Greiner R; Vock P. et al. Longterm Changes Induced by High-Dose Irradiation of the Head and Neck Region: Imaging Findings. RadioGraphics 1997; 17: Hermans R. Imaging of mandibular osteoradionecrosis. Neuroimag Clin N Am 2003; 13: Radiation-induced Changes in Bone Mitchel M, Logan PM. RadioGraphics 1998; 18: Page 12 of 12