Salivary gland tumors: Evaluation with two-phase helical CT

PURPOSE: To evaluate two-phase helical computed tomography (CT)in the chara cterization of salivary gland tumors. MATERIALS AND METHODS: Sixty-four patients with major salivary gland tumors underwent two-phase helical CT. the histopathologic diagnosis was Obtained by means of surgical resection or biopsy in all patients. After the inject ion of 90 mL of contrast material at a rate of 3 mL/sec, helical CT scans w ere obtained at early and delayed phases with scanning delays of 30 and 120 seconds, respectively The attenuation change and enhancement patterns in t he tumors were assessed. The attenuation change in the tumor also was asses sed quantitatively as the ratio of the CT number (in Hounsfield units) at d elayed phase scanning to that at early phase scanning. RESULTS: There were 35 pleomorphic adenomas, nine Warthin tumors, and 20 ma lignant tumors. Two-phase helical CT showed increase in attenuation in 30 ( 86%) pleomorphic adenomas, decrease in eight(89%)Warthin tumors, and increa se in 11 (55%) and no change in eight (40%) malignant tumors at delayed pha se scanning. A multinodular enhancement pattern was found in only 12,(34%) pleomorphic: adenomas. The ratio of CT numbers was significantly different between Warthin tumors and pleomorphic adenomas and between Warthin tumors and malignant tumors. CONCLUSION: The analysis of enhancement patterns by using two-phase helical CT will be helpful in the differential diagnosis of salivary;gland tumors.