Maarten Van Leeuwen MD, PhD, PRESENTER: Nothing to Disclose

Abstract: HTML Purpose: The appropriate surgical therapy of parotid tumours is defined by the pathological nature of the tumor and by its location relative to the facial nerve. A study was performed to assess the additional value of ultrasound (US) and magnetic resonance imaging (MRI) to physical examination and fine needle aspiration (FNA) in the pre-operative evaluation of parotid gland tumours. Methods and Materials: Prospectively, 82 patients with parotid tumours were included in whom eventually 61 benign and 21 malignant tumours were found; 74 patients underwent resection. On physical examination the tumor was judged as superficial to, deep to, or involving the facial nerve. In 80 patients FNA was performed. On US and MRI various imaging characteristics and the presumed histological diagnosis were assessed. Tumor location relative to the expected course of the facial nerve was defined on US by taking the retromandibular vein (RV) or mastoid-mandible line as landmarks. On MRI, the FN-line, between mandibular angle and posterior part of the digastric muscle, and the U-line, between RV and posterior arch of the cervical vertebra, were used as landmarks to indicate the expected course of the facial nerve. The results were compared to the definite histology and the location of the facial nerve relative to the tumor during surgery. Results: Of the individual MRI imaging characteristics, incomplete demarcation from normal parotid tissue demonstrated the highest positive predictive value (PPV 0.48) for malignancy. Using all imaging features, MRI demonstrated a PPV for malignancy of 0.7. On US, irregular margin, inhomogeniety, and extraglandular extension yielded the highest PPV for malignancy of only 0.33. Using all imaging features, US demonstrated a PPV for malignancy of 0.38. Superficial location relative to the facial nerve was well predicted on physical examination (PPV 0.8), slighly better on MRI (FN-line: PPV 0.83, U-line PPV 0.87) and worse on US (PPV 0.7). PPV for prediction of tumours involving, or deep to, the facial nerve; both with a higher chance for post-operative facial nerve paresis, was 1.0 for palpation, 0.82 for MRI, and 0.55 on US. Cytology, obtained at FNA, rightly predicted the malignant or benign nature of the tumour in all 80 cases. Conclusion: FNA is the only accurate test to classify a parotid gland tumour as benign or malignant. Palpation and MRI are superior to US in predicting facial nerve involvement. There is no role for ultrasound for locating or characterizing parotid tumours.       Questions about this event email: m.s.vanleeuwen@azu.nl

Van Leeuwen MD, PhD, M, What Is the Added Value of Ultrasound and MRI to Physical Examination and FNA in the Pre-operative Evaluation of Parotid Tumours?.  Radiological Society of North America 2003 Scientific Assembly and Annual Meeting, November 30 - December 5, 2003 ,Chicago IL. http://archive.rsna.org/2003/3105066.html