Advanced MRI Sequences (Diffusion and Perfusion): Its Value in Parotid Tumors

Abstract

Introduction: Tumors of salivary glands constitute 3% of neoplasms of the body. Clinical signs and symptoms usually occur in tumors at advance stages. Dynamic-contrast-enhanced and diffusion-weighted MR sequences have been described as useful diagnostic tools in other locations. Our goal is to evaluate the utility of these techniques for parotid tumors. Material and methods:We retrospectively reviewed the Parotid tumors operated by our department whit Dynamic-contrast-enhanced and diffusion-weighted MR sequences between 2012 and 2015. We correlate the results with the final histopathological diagnosis.Results: From 44 parotid tumors studied, Warthin tumors were the most common (43%). They showed high enhancement and high washout in perfusion series, so as low ADC values. Pleomorphic adenomas (41%) are hyperintense tumors in T2, with moderate constant enhancement in perfusion and high Apparent Diffusion Coefficient values. It is not possible to establish consistent results for malignant tumors given their underrepresentation in this sample. Conclusion:Advanced MRI techniques contribute to the differential diagnosis of parotid tumors. Perfusion is useful in diagnosis of Warthin tumors and Pleomorphic adenomas. There is greater overlap in other tumors, for which diffusion-weighted MR sequences can help in discriminating malignancies. Both malignancies and Warthins show low Apparent Diffusion Coefficient values.

RETRACTED ARTICLE: The diagnostic value of combined dynamic contrast-enhanced MRI (DCE-MRI) and diffusion-weighted imaging (DWI) in characterization of parotid gland tumors

“…However, there is still overlap between benign and malignant tumors in terms of imaging appearance on conventional MRI. In the last years, the role of functional MRI (DWI and DCE-MRI) have been assessed in head and neck neoplasms to overcome the overlap in imaging appearance of benign and malignant tumors on conventional MRI [1].…”

“…Salivary gland tumors (SGTs) account for nearly 3% of tumors that occur in the maxillofacial region; about 80% of all SGTs are found in the parotid gland with an incidence of malignancy within the parotid gland tumors about 20%. Proper preoperative diagnosis of these tumors is essential for adequate surgical planning [1]. Clinical assessment has a limited role in diagnosing malignant parotid tumors.…”

“…Several imaging modalities such as ultrasonography and computed tomography (CT) may aid in diagnosis of parotid gland tumors, but now magnetic resonance imaging (MRI) is considered to be the imaging modality of choice in preoperative diagnosis of parotid gland tumors and differentiating benign from malignant ones [1]. MRI gives information on the exact location, extent of the lesion, relation to the surroundings structures, and allows assessment of perineural spread and bone invasion.…”

Cross-sectional imaging and cytologic investigations in the preoperative diagnosis of parotid gland tumors – an updated literature review

“…A large number of studies have been able to differentiate between benign and malignant parotid tumors using DWI-MRI [1,10,15,26,27,[29][30][31][32][33], but other studies failed to demonstrate an accurate diagnosis [20,22].…”

“…In most studies, differentiation of PMA from WT, as well as PMA from malignant tumors was successful based on ADC values [15,17,20,25,26,32,34]. Other authors did not obtain significant results regarding the differentiation of WTs from malignant tumors due to the overlap of their ADCs values [25,29,30,32,34]. However, differentiation of WTs from malignant ones, based on ADC maps, was possible in some studies [32,[35][36][37].…”