Palatal lesions: discriminative value of conventional MRI and diffusion weighted imaging

Abstract

Objective: To evaluate and compare the ability of conventional MRI, diffusion-weighted imaging (DWI) and a combination of both MRI techniques to differentiate malignant and benign palatal lesions. Methods: A retrospective review of MRI findings was performed in patients with pathologically confirmed palatal lesions between January 2012 and December 2014. Each lesion was evaluated with conventional MRI characteristics, including enhancement, inner texture, margin, adjacent soft-tissue involvement and cervical lymph node, and/or apparent diffusion coefficient (ADC) value. Statistical analyses were performed to assess the differential performance of each parameter separately and together. Results: A total of 42 patients (24 males, 18 females; age: 54.9 6 16.4 years) were investigated. The optimal cut-off ADC value to distinguish malignant from benign lesions was 1.02 3 10 23 mm 2 s 21 , with a sensitivity of 87.5% and a specificity of 75.0%. Conventional MRI showed a sensitivity of 87.1% and a specificity of 63.6%. Combination of conventional MRI and ADC scores increased sensitivity to 100% and specificity to 75.0%. The AUCs did not differ significantly between conventional MRI alone, DWI alone and integration of both. Conclusion: Additional DWI does not substantially improve differential ability of conventional MRI. However, combining ADC values with conventional MRI improves both sensitivity and specificity, which is of worth to be further validated in prospective studies with larger sample sizes. Advances in knowledge: Combination of conventional MRI and ADC scores could increase the ability to differentiate malignant from benign palatal lesions, with a sensitivity of 100% and specificity of 75.0%, although without statistical significance. INTRODUCTIONThe palate separates the oral from the nasal cavity and is anatomically composed of soft and hard parts. The hard palate is composed of mucosal surface and minor salivary glands located between the mucosal surface and the underlying bone. The soft palate is formed by squamous mucosa and muscle fibers, and contains a smaller number of minor salivary glands compared with the hard part. Palatal lesions include a variety of pathological types, 1 and squamous cell carcinoma (SCC) is the most common malignancy. Tumours of the minor salivary glands are the most common type of submucosal masses, and malignant tumours account for approximately half of them.2 Various types of mesenchymal tumours, such as fibromas, lipomas, schwannomas, neurofibromas, haemangiomas and lymphangiomas, also involve the palate.

Differentiation between benign and malignant palatal tumors using conventional MRI: a retrospective analysis of 130 cases

“…Conventional magnetic resonance imaging (MRI) plays an important role in delineating the extent of palatal lesions and identifying perineural spread as well as spread to lymph nodes because of its superior soft tissue resolution, 1,7 thereby complementing clinical examination. Although diffusion weighted imaging (DWI) and other advanced MR approaches have been used to assess palatal tumors, 8,9 Yuan et al 9 noted that DWI did not dramatically improve the ability of conventional MRI to differentiate between benign and malignant palatal lesions, indicating that routine MRI remains the mainstay imaging modality in the palate.…”

Diffusion‐weighted magnetic resonance imaging in the palatal tumors: Usefulness of apparent diffusion coefficient value for characterization of benign and malignant tumors

“…Ishii et al 2 showed that the internal echo pattern on the ultrasonogram of a palatal tumor was found to reflect the pathologic structure of the tumor. On DWI, Yuan et al 4 showed that the optimal cut‐off ADC value to distinguish malignant from benign lesions was 1.02 × 10 −3 mm 2 s −1 , with a sensitivity of 87.5% and a specificity of 75.0%. In this study, the mean ADC value of squamous cell carcinoma (1.10 ± 0.11 × 10 −3 mm 2 s −1 ) was significantly lower than that of pleomorphic adenoma (1.49 ± 0.41 × 10 −3 mm 2 s −1 , P = .046) and another benign tumor (1.85 ± 0.40 × 10 −3 mm 2 s −1 , P = .000).…”

“…We consider that our results were preliminary study, and further research is necessary to validate these results. Yuan et al 4 showed DWI in 42 patients with palatal lesions. Oda et al 8 indicated DWI in 57 oral and maxillofacial lesions.…”

“…However, it is very difficult to make a correct diagnosis of a palatal salivary gland tumor by physical examination 2 . In recent years, computed tomography (CT) 3 and magnetic resonance imaging (MRI) 4 can be useful techniques for the preoperative evaluation of palatal lesions.…”

Diffusion-weighted MRI for differentiation between sialadenitis and pleomorphic adenoma

“…5 In general, lesions and tumours with high cellularity or cellular swelling tend to present lower apparent diffusion coefficients (ADCs). Accordingly, ADC values have been reported to be lower in malignant tumours, as compared with benign tumours, [6][7][8] and inflammatory lesions. 9 For alterations of the salivary glands, MRI might be decisive for the diagnosis and can also contribute to defining the stage of the disease.…”