The Study On 16-Slice Spiral CT Perfusion Imaging And Its Correlation With Angiogenesis Of Solitary Pulmonary Mass

Purpose The research is to evaluate the clinical value of CT perfusion imaging(CTPI)in differentiating solitary pulmonary mass.The correlation of the parameters and time-density curve(TDC)of CTPI and microvessel density(MVD)and vascular endothelial growth factor(VEGF)in solitary pulmonary mass by using 16-slice spiral CT and the feasibility on assessing angiogenesis of solitary pulmonary mass in vivo by CTPI were also discussed. Materials and Methods(1)Fifty-two patients(34 men,18 women;age range,13～75 years;mean age,52.8years;size range,1.9 - 6.5 cm;mean size of the lesions,3.8cm.)with solitary pulmonary mass who were detected by radiographing or plain CT scanning were chosen to perform 16-slice spiral CT perfusion scanning.Among them,39 performed operation within ten days after scanning,12 performed thoracoscopy or fiberoptic bronchoscopy.Histology/Cytology revealed 38 lung cancer(16 squamous cell cancer;18 adencarcinoma;2 adenosquamous carcinoma and 2 small-cell carcinoma),7 inflammatory solitary mass(3 inflammatory pseudotumor;2 granuloma;2 lung abscess),the benign solitary mass were 7 cases(6 tuberculoma;1 pulmonary sclerosing hemangioma).(2)All patients first underwent unenhanced CT scanning with SIMENSE Sensation 16 CT scanner.Then four adjacent sections locating the center of the lesion were chosen to be the target sections and CT perfusion scanning in first pass phase(FPP)was performed by the "Toggling-Table" technology.The section thickness was 3mm for lesions less than 3cm and 6mm for lesions largerer than 3cm.For perfusion scanning,following parameters:120KV,80mA, cine full,0.5second scan time per circle,non-ionic agent(350 mg I/ml)40 ml, infusion rate of 4.0ml/sec,scanning started at 6 seconds after the beginning of injection and acquisition time of 30 seconds were used.(3)All perfusion images were transferred into Volume Wizard workstation.①Data analysis was performed with body-perfusion,then the computer could automatically create color maps of blood flow(BF),relative blood volume (rBV),time of top peak(TTP),and permeability(Pm)and parameter values of region of interest(ROI);②Data analysis was performed with DynEva,the time-density curves(TDC)of ROI were created automatically and the parameter value of peak Hu(PH)was recorded,then the perfusion value(PV)of ROI was calculated using the maximum-slope method.(4)Pathologic types of specimens were determined by hematoxylin and eosin(HE)staining.The expressions of CD34 and VEGF in 39 cases were detected by LSAB immunohistochemistry staining,then the MVD counting was performed and the expressions of VEGF was recorded.Results(1)PH,PV and rBV from both the malignant and the inflammatory were higher than those of the benign(P＜0.05),BF and Pm from both the malignant and the inflammatory were significantly higher than those of the benign (P＜0.01).No statistically significant differences in PH,PV,BF and rBV were found between the malignant and the inflammatory(P＞0.05),but Pm of the malignant was higher than that of the inflammatory(P＜0.05).TTP of the benign was higher than that of the malignant and the inflammatory,but there was no statistically difference in TTP between the malignant and the inflammatory or between the inflammatory and the benign(P＞0.05).(2)Youden's index was used to evaluate the diagnostic value of all the parameters of CTPI in FPP.The value of PH,PV,rBV,BF and Pm were 27.8%,44.4%,50%,64.3%and 75.2%,respectively.The value of BF combined Pm(82.4%)was the hightest.(3)MVD and VEGF of the malignant and the inflammatory were higher than that of the benign(P＜0.05),while no statistically significant difference was found between the malignant and the inflammatory(P＞0.05).The malignant lesion had scatted microvessels with unintegral wall and with irregular morphology,VEGF was mainly distributed in cytoplasm and membrane of cell,some demonstrated positive staining in the basal lamina or extracellular stroma;the inflammatory lesion had scatted microvessels with integral wall and with regular morphology,the expression of VEGF was weak positive;the benign lesion had a small quantity of microvessels,the expression of VEGF was negative mostly.There was positive correlation between MVD and VEGF (r=0.504,P＜0.01)(4)PH,PV and rBV were positively correlated with MVD and VEGF (P＜0.05),BF and Pm were significantly correlated with MVD and VEGF.But TTP were not related to MVD and VEGF(P＞0.05).(5)There were statistical differences in the distribution of the TDC types among the three groups(P＜0.05).The TDCs from the malignant rose at the beginning but then dropped slightly or showed no dropping,the location of the peak was delayed to aorta(Type A).Most of the TDCs of the benign leveled off with a rather low summit(Type C).Some TDCs of the inflammatory presented fast-up-fast-down with a rather high summit and the location of the peak was advanced to aorta(Type B),some presented Type A.No statistically difference in MVD and VEGF was found between Type A and Type B(P＞0.05),but there was statistically difference in MVD and VEGF between Type A and Type C or between Type B and Type C(P＜0.05).Conclusions(1)PH,PV,BF,rBV and Pm can contribute to the discrimination of the benign from the malignant and the inflammatory,especially BF combined Pm is great value for the differential diagnosis of solitary pulmonary mass.The combination of a number of perfusion indexes is more valuable than single indexe in diagnosis.The combination of BF and Pm is suggested as the quantitative index in the differential diagnosis.(2)Except TTP,the other CT perfusion indexes were respectively correlated with MVD and VEGF very well,BF and Pm were significantly correlated with MVD and VEGF.(3)To some extent,TDC can reflect the blood supply and angiogenesis of solitary pulmonary mass.But the contribution to differentiating between the malignant and the benign is limited.(4)16-Slice Spiral CT Perfusion Imaging can reflect the angiogenesis state of solitary pulmonary mass very well and provide its quantitative perfusion information exactly,thus it offers an effective method to assess the angiogenesis state of pulmonary mass in vivo.