Differentiating benign and malignant salivary gland tumours: diagnostic criteria and the accuracy of dynamic contrast-enhanced MRI with high temporal resolution

Abstract

The authors Phong Dai Lam and Ami Kuribayashi equally contributed to this work.Objective: To determine the optimal diagnostic criterion of dynamic contrast-enhanced MRI (DCE-MRI) for predicting salivary gland malignancy using a dynamic sequence with high temporal resolution, as well as the accuracy of this technique. Methods: The DCE-MRI findings of 98 salivary gland tumours (74 benign and 24 malignant) were reviewed. MR images were sequentially obtained at 5-s intervals for 370 s. Two parameters, peak time and washout ratio (WR) were determined from the time-signal intensity curve. The optimal thresholds of these parameters for differentiating benign and malignant tumours were determined, along with the diagnostic accuracy of the criterion using these thresholds. Results: A peak time of 150 s and a WR of 30% were identified as optimal thresholds. As the criterion for malignancy, the combination of peak time ,150 s and WR ,30% provided a sensitivity of 79% (19/24), specificity of 95% (70/74) and an overall accuracy of 91% (89/98). Three of the five false-negative cases were malignant lymphomas of the parotid gland. Conclusion: Peak time ,150 s with WR ,30% comprised the optimal diagnostic criterion in predicting salivary gland malignancy, providing a sensitivity of 79% and specificity of 95%. The use of high temporal resolution might improve the accuracy of DCE-MRI. Advances in knowledge: Although several studies have reported the usefulness of DCE-MRI in the differential diagnosis of salivary gland tumours, the specific diagnostic criteria employed have differed widely. We determined the optimal criterion and its accuracy using a dynamic sequence with high temporal resolution.

Parotid gland lesions: separate and combined diagnostic value of conventional MRI, diffusion-weighted imaging and dynamic contrast-enhanced MRI

“…Significant differences were found in the mean ADC values between Warthin tumours and pleomorphic adenomas, as well as between Warthin tumours and benign lesions. 17 Motoori et al 26 reported higher ADC values in pleomorphic adenomas than malignant tumours. An ADC cut-off value of 1.315 3 10 23 mm 2 s 21 had sensitivity and specificity of 82.1% and 81.2%, respectively, for distinguishing between pleomorphic adenomas and malignant tumours.…”

Delayed enhancement in differential diagnosis of salivary gland neoplasm

“…and malignant parotid lesions (4,(13)(14)(15)(16). However, recent studies have demonstrated a comparable high sensitivity and specificity between these imaging modalities (7,17,18).…”

Feasibility of a novel classification for parotid gland cytology: A retrospective review of 512 cytology reports taken from 4 United Kingdom general hospitals

“…Table summarizes how imaging was utilized in this study. There is evidence to suggest that contrast enhanced MRI has comparable diagnostic accuracy to FNAC in differentiating benign from malignant disease . Traditionally, cross‐sectional imaging (ideally MRI) is considered in patients who have clinical or sonographic features of malignancy and lesions with deep lobe extension; it may also have a role in Sal 3 and Sal 4 lesions.…”