diagnostic value of magnetic resonance spectroscopy in differentiation of benign and malignat salivary gland tumors in compari-son with pathology results

Abstract

Background: Differentiation between benign and malignant parotid tumors before surgery is important because it can change the therapeutic planning for patients. In this study we evaluated the role of Magnetic resonance spectroscopy (MRS) in differentiation of benign from malignant parotid tumors. Materials and Methods: 40 patients entered with salivary gland tumor especially parotid) that candidated for surgery in this study. Patients selected in Amiralam hospital and did MRI in Imam Khomeini hospital. In this study, on these patients Magnetic resonance spectroscopy (MRS) was performed at 135 and 270 Time of Echo, and the choline/creatine ratio was determined. Regarding to the cytological results, patient divided to warthin, benign and malignant tumors and ROC curves used to determine the best cut off points. Results: 40 patients entered in this study, 25 had benign non warthin tumors, 9 malignant tumors and 6 warthin tumors. In differentiation benign from malignant tumors TE136 was stronger. The best cut off point of Choline to Creatine ratio in TE: 136 was 1.92 with sensitivity 81 % and specificity 89% and in TE 270 was 1.76 with Sensitivity 89% and specificity 71%.  Choline/creatine ratio <1.25 can rule out the malignancy with sensitivity of 92% and ratio > 1.76 strongly suggest malignancy (with10% specificity). MRS was not able to differentiate benign non warthin from warthin tumors. Conclusion: According to this study, Choline/ creatine ratio in MRSpectroscopy can be helpful as noninvasive method in differentiation of benign from malignant tumors.