Clinical Research Of Perfusion Imaging Using 64-slice SCT In Diagnosis Of Salivary Gland Tumor

Objective: 1 To investigate the perfusion characteristics of the normal salivary gland and tumor tissue and to examine the relationship between changes in perfusion and histologic changes of salivary gland tumor. 2 To assess clinical utility of CT perfusion imaging using 64-slice spiral CT (SCT) in the diagnosis of salivary gland tumor. .Methods: Total 33 patients of salivary gland tumor (23cases in parotid gland, 8 cases in submandibular gland , 1 case in sublingual gland and 1 case in palatine gland; 15 benigns and 18 malignants)underwent CT scan. 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 second 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 and the contralateral normal salivary gland tissues 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 Salivary gland tumor of the values of BF,BV, MTTand PS of the tumors( 174.58 ml·100g^-1·min^-1,21.54±7.99 ml·100g^-1,12.93±1.22 s,28.36±5.43 ml·100g^-1·min^-1)were obviously higher than those of the normal salivary gland tissues(30.84±6.81 ml·100g^-1·min^-1,4.22±1.97 ml·100g^-1,10.49±1.91s,7.45±1.49 ml·100g^-1·min^-1).The values of BF,BV,MTT and PS between Salivary gland tumor and the normal salivary gland tissues were statistically significant(P﹤0.01) .The values of BF,BV and PS of the malignant tumors(213.14±17.91 ml·100g^-1·min^-1,28.41±4.64 ml·100g^-1,31.94±4.65ml·100g^-1·min^-1) were higher than those of benign tumors( 142.45±27.02 ml·100g^-1·min^-1,15.82±5.11 ml·100g^-1,25.38±4.13 ml·100g^-1·min^-1)significantly. The values of BF,BV,MTT and PS between benign and malignant tumors were statistically significant(p<0.01) and the values of MTT was not statistically significant(P>0.05). 2 If the threshold of BF>210 ml·100g^-1·min^-1 or PS>30 ml·100g^-1·min^-1 or BF>210 ml·100g^-1·min^-1 and PS>30 ml·100g^-1·min^-1 ,the sensitivity of PCT in estimating the potential malignancy of the tumors were 73.3,94.4%,81.8%,specificity were 73.3%,83.3%,78.8%,accuracy were 81.8%,94.4%,81.8% respectively.3 Pseudocolour perfusion imaging were direct and convenient for qualitative diagnosis of salivary gland tumor, and perfusion values were needed for quantitative analysis.Conclusions:CT perfusion imaging is an accurate means for analyzing blood perfusion state in salivary tumors in vivo and it has an important clinical utility in differentiating benign and malignant tumors of the salivary gland .