CT Perfusion Imaging And Fine Needle Aspiration Cytology Of Applied Research In Diagnosing Salivary Gland Tumors

Objective: To assess clinical utility of CT perfusion imaging using 64-slice spiral CT (SCT) and fine needle aspiration cytology in the diagnosis of salivary gland tumor.Methods: Total 36 patients of salivary gland tumor (26 cases in parotid gland, 8 cases in submandibular gland , 1 case in sublingual gland and 1 case in palatine gland; 23 benigns and 13 malignants) underwent CT scan. Fine needle aspiration cytology was done before surgery with 10～20ml syringe. The model of needle was 7. Fastened the tumor with the left hand and sticked the tumor with the syringe by the right hand after generally disinfected on the puncture part. Then aspirated pathological tissue from the different direction under pressure. When we aspirated enough pathological tissues, we wiped out the negative pressure then withdrew the needle. The aspiration smears were divided into two or four parts. When they dryed, they were fixed with methanol and generally did Wright staining. To observe the outcome under the light microscope. At first, plain CT scan was performed to localize central slices of tumor, then perfusion imaging of neoplasms was undergone with cine mode on 64-slice SCT, slice thick 5mm×8i. Bolus injection was done by using 50ml nonionic contrast agent(Ultravist300, including I 300g/ml), at a flow rate of 4ml/s with a power injection, 5～15 seconds delay, and data acquisition lasted for 50 seconds. These data were processed on a GE AW 4.22 workstation using perfusion 3 software package, and perfusion parameter, including blood flow(BF), blood volume(BV), mean transit time(MTT) and permeability surface(PS) of tumor tissue were measured by the central volume principle(CVP) and deconvolution method(DM) and statistically analyzed . The surgical and pathological outcomes were collected for comparison.Results: 1 The values of BF, BV and PS of the malignant tumors[217.9±9.97 0.01ml/(g·min),29.86±2.81 0.01ml/g,34.01±2.34 0.01ml/(g·min)] were higher than those of benign tumors[139.35±6.950.01ml/(g·min),15.02±1.73 0.01ml/g,24.30±2.29 0.01ml/(g·min)]significantly. The values of BF, BV and PS between benign and malignant tumors were statistically significant(P<0.05) and the values of MTT was not statistically significant(P>0.05).2 The sensitivity, specificity and coincidence rates of CT perfusion imaging were 92.3%(12/13), 87.0%(20/23) and 88.9%(32/36) respectively.3 There were 13 cases of 36 patients who eventually were diagnosed as malignant salivary gland tumors. The sensitivity, specificity and coincidence rates of fine needle aspiration cytology were 84.6%(11/13), 95.7%(22/23) and 91.7%(33/36) respectively.4 The negative cases of fine needle aspiration cytology can be correctly identified as malignant by CT perfusion imaging.Conclusions: CT perfusion imaging can provide salivary gland tumors with information of microcirculation perfusion. It will contribute to the identification of benign and malignant tumors,paralled with fine needle aspiration cytology, can greatly improve the accuracy of salivary gland tumors .