Advantages of contrast-enhanced CT combined with DCE-MRI in identifying malignant parotid tumor.

Objective: To study the value of single and combined application of contrast-enhanced computerized tomography (CT) and dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) in diagnosing parotid tumors.

Methods: In this retrospective study, 82 patients with parotid gland mass who received contrast-enhanced CT and DCE-MRI detection in The First People's Hospital of Huzhou from March 2018 to March 2022 were selected as study subjects. The nature of the parotid tumor was pathologically examined following the surgery. According to the pathological diagnosis results, these patients were divided into a benign group (n=59) and a malignant group (n=23). All patients underwent contrast-enhanced CT and DCE-MRI examinations. The diagnostic accuracy rates of contrast-enhanced CT, DCE-MRI and the joint application were compared. The CT or MRI images of benign and malignant parotid tumors were compared. The correlation of parotid cancer with the imaging features was analyzed. Diagnostic efficiency of contrast-enhanced CT, DCE-MRI and joint application for parotid cancer was assessed by receiver operating characteristic curve.

Results: In terms of diagnostic accuracy, there was a significant difference between contrast-enhanced CT combined with DCE-MRI and contrast-enhanced CT alone (95.12% vs. 81.71%, P<0.001), and between the joint application and DCE-MRI alone (95.12% vs. 86.58%, P=0.004). Results of contrast-enhanced CT revealed statistical differences in tumor boundary, tumor size, calcification and cystic degeneration between benign and malignant tumors (P<0.05), but no obvious difference in lymph node enlargement between the two groups. MRI results showed that there were differences in the DCE-MRI time-signal intensity curve and ADC value between benign and malignant tumors (P<0.05). Correlation analysis results showed that the malignant tumor was negatively correlated with tumor boundary, calcification, cystic degeneration and ADC values, and it was positively correlated with DCE-MRI time-signal intensity curve and tumor size (P<0.05). Analysis of diagnostic efficacy showed that contrast-enhanced CT combined with DCE-MRI were significantly better than contrast-enhanced CT alone in terms of sensitivity and specificity (P<0.05). Moreover, the sensitivity of the joint application was also higher than that of MRI alone, while no obvious difference was found for specificity between joint application and MRI alone. The areas under the curve of contrast-enhanced CT combined with DCE-MRI in diagnosing malignant parotid tumor was remarkably greater than that of CT or MRI alone (P<0.05).

Conclusion: Contrast-enhanced CT combined with DCE-MRI can significantly improve the diagnostic accuracy, sensitivity and specificity for malignant parotid tumor, and the joint application was able to point out the direction of targeted surgical treatment plans.