The significance of CT scan or MRI in the evaluation of salivary gland tumors.

Imaging modalities such as CT scan or MRI are frequently employed for the diagnosis of neoplastic lesions in the salivary glands. To evaluate the efficacy of the CT scan and the MRI in differentiating malignant neoplasm from benign lesions, 120 CT scans and 31 MRIs were retrospectively analyzed from 147 patients with salivary gland masses. All images were analyzed focusing on the presence of several relevant features. The pathologic results were matched with radiological features and also tabulated with radiological assessment. For the CT scans, the contour and margin of the lesion and tissue plane obliteration were found to be statistically significant indicators for malignant neoplasms. Among 69 CT scans interpreted as 'benign' by a radiologist, five cases (7%) were histologically diagnosed as 'malignant'. On the other hand, 20 out of 51 CT scans (39%) were misinterpreted as 'malignant'. For MRI, two out of 14 cases (14%) were radiologically misdiagnosed as 'benign' and six out of 17 patients (35%) as 'malignant'. In conclusion, whereas both the CT and MRI showed a similar level of accuracy in evaluation of salivary gland tumors, they showed a considerable tendency of misdiagnosis, especially by interpreting benign tumors as 'malignant'.