Imaging the treated oral cavity and oropharynx

Imaging of the post-treatment neck

Post-treatment imaging of the neck is complex. It is important to have an understanding of the expected treatment related appearances as well as the possible complications. Common findings after radiation therapy include generalised soft-tissue oedema and thickening of the skin and platysma muscle. There are a number of complications of radiation that may be seen on imaging, including osteoradionecrosis, chondronecrosis, and accelerated atherosclerosis. Surgical procedures are variable depending on the primary tumour site and extent. The use of flap reconstructions can further complicate the imaging appearances. Any new nodule of enhancement or bone/cartilage erosion should raise concern for tumour recurrence. It is also important to assess for nodal recurrence. A standardised approach to reporting may help to increase accuracy and guide treatment decisions.

Detection of cutaneous invasion by malignant head and neck tumors with MDCT

OBJECTIVE

Cutaneous invasion by direct infiltration and metastasis, in malignant head and neck tumors, has a distinct impact on therapeutic options, especially surgical procedures, curative intent, and overall prognosis. Therefore, the purpose of this study was to determine the diagnostic accuracy of MDCT in detecting cutaneous invasion by malignant head and neck tumors.

MATERIALS AND METHODS

Nineteen patients with malignant head and neck tumors and clinical suspicion of cutaneous invasion routinely underwent contrast-enhanced 16-row MDCT (Philips MDCT MX 8000) of the region of interest in the axial plane before surgical intervention. The following parameters were used: 16mmx0.75mm detector collimation; 3mm reconstructed slice thickness; 1.5mm increment; 0.75s rotation speed; 120kV, 200mAs; and 100ml non-ionic contrast agent, i.v., with a flow of 2.0ml/s and a scan delay of 50s. The studies were reconstructed with a soft tissue algorithm (W400, L100 HU), and coronal and sagittal planes were also reconstructed. The axial images were retrospectively reviewed in consensus by two radiologists for the evidence of cutaneous invasion blinded to the histological results. The MDCT results were correlated with histology that was obtained by punch biopsy or surgery.

RESULTS

MDCT correctly revealed 11 of 11 cases with cutaneous invasion, and correctly excluded 4 of 8 cases without cutaneous invasion. The diagnostic accuracy of MDCT in detecting cutaneous invasion showed a sensitivity of 100%, a specificity of 50%, and an overall accuracy of 79%.

CONCLUSION

MDCT reconstructed with a soft tissue algorithm has a good sensitivity and moderate overall accuracy in detecting cutaneous invasion by malignant head and neck tumors.