Objective To evaluate the clinical value of low-dose scan with 1 6-slice spiral CT in follow-up of the adult patients with secondary active pulmonary tuberculosis.Methods 130 patients with secondary active pulmonary tuberculosis were enrolled CT scans in the study.Routine dose (120 mA)and the following low-dose (1 5-40 mA)scanning was used with the same tube voltage of 120Kv and other factors.Image quality,imaging characteristics of the lesions,CT dose index and dose length product of two scans were evaluated.Meanwhile,the effective dose,quantitative measurement and evaluation of differences were analyzed.Results Between the routine scan and low-dose one,no significant difference in image quality was found(P = 0.121 0).No significant differences were found between two scans in 7 imaging features including ground-glass appearance,tree-in-bud sign,consolidation, cavity,bronchiectasis,bronchial stenosis and intralesional calcification (P >0.05).The X-ray radiation dose was decreased signifi-cantly with low-dose CT.Conclusion Low-dose spiral CT shows more advances in detection of secondary active pulmonary tubercu-losis as good as the conventional doses CT,and is used in the follow-up of the pulmonary tuberculosis.

Objective To explore the value of CT venography (CTV) in diagnosis of cerebral venous sinus thrombosis (CVST) . Methods 16 patients with CVST were examined by CTV. 2D and 3D vascular images were reconstructed through workstation. Results Filling-defect was seen as "empty triangle sign" on the axial image.Multiple CVST were displayed in 11 patients,among them,8 cases involved superior sagittal sinus,3 cases involved lateral sinus. Single CVST was displayed in 5 patients,2 cases involved superior sagittal simes,2 cases involved straight sinus,1 case involved inferior sagittal sinus. The irregular narrowing or occlusion of the sinus and dilation of the branch of vein were observed in all 16 patients on 2D or 3D images. Hydrocephalus, cerebral infarction and cerebral hemorrhage were seen in 11 cases, 6 cases and 4 cases respectively. Conclusion CTV is a sensitive and distinctive technique in diagnosing CVST.

Objective To explore the fibrotic stroma characteristics of orthotopic liver cancer in rat and the relationship with MR delayed contrast enhancement.Methods 4 Wistar rats with orthotopic liver cancer underwent conventional triphasal and longer-de-layed contrast-enhancement MR scanning.12 HCC specimens obtained from the four Wistar rats were sliced and stained with HE, picric-sirius red,Verhoeff Van-Gieson elastic fiber,Gordon-Sweets reticular fiber and anti-α-SMA immunohistochemical staining.The relationshp between intratumoral fibrotic stroma and MR delayed phases of the 1 2 tumors were analyzed.Results Collagen fiber was expressed mainly in tumor fibrous septum.Elastic fiber distributed in tumor fibrous septum and the artery wall.Reticular fiber dis-tributed in fibrous septum of the regenerative nodules,portal area and tumor psuedocapsule.Integrated optical density (IOD)value of collagen fiber,elastic fiber and reticular fiber analyzed by Image-pro Plus6.0 were 0.102±0.020,0.063±0.018 and 0.109±0.032, respectively.As a result,the amount of collagen and elastic fibers were statistically different (P<0.01),and so were reticular fibers and elastic fibers (P<0.01).And there was a positive correlation between collagen fiber and MR delayed contrast enhancement (P<0.05).Conclusion MR delayed contrast enhancement of hepatic cancer in rat is closely associated with the collagen fiber,thus this fiber in liver cancer can be evaluated noninvasively by MRI.

Objective To investigate the potential of AFP-targeted ultrasmall superparamagnetic particles of iron oxide (USPIO) molecular probe in specific detection of hepatocellular carcinoma (HCC) with MRI.Methods The targeted probe was synthesized by conjugating AFP antibody with modified USPIO.Two groups treated with AFP-USPIO and USPIO were set up in the study.The HepG2 cells were incubated with AFP-USPIO or USPIO (100 μg/ml) respectively with the dosage of 50 μ1,100 μl or 150 μl for 4 hours,followed by MR imaging in vitro.The signal-noise ratio (SNR) of the cells on T2-weighted image (T2WI) was measured.The rat models with orthotopic HCC were divided into two groups with 5 rats for each group at random.Pre-and post-contrast enhanced (after 1 hour) MR imaging were performed with caudal vein injection at a dosage of 20μg/ml.The contrast noise ratio (CNR) on T2WI and the difference of CNR between pre-and post-enhancement or between both groups were calculated.The relationship of SNR or CNR with the iron particles in cells or tumors was confirmed by Prussian blue iron staining.Results Cytology experiment showed the SNR in both groups was decreased with the increase of the dosage of AFP-USPIO or USPIO,indicating statistically significantdifference in SNR among three different doseage groups (P＜0.05).Prussian blue iron staining showed that the iron particles in cells were increased with the increase of AFP-USPIO dosage,and was negatively correlated with SNR (P=0.00,r=-0.926).However,the iron particles were less in cells in USPIO group.The CNRs of liver tumors in Wistar rat of pre-and post-AFP-USPIO injection were 2.05±0.88 and 0.96±0.31 respectively,indicating a significant difference (P=0.028,t=3.380).However,the CNRs in USPIO group,2.25±1.50 and 2.57±1.49,showed no statistical difference (P=0.275,t=1.263).The CNR after enhancement also had a statistical difference between both groups(P=0.042,t=3.487).Pathological results confirmed more iron particles in tumor tissues in AFP-USPIO group,whereas less in USPIO group.Conclusion AFP-USPIO molecular probes can initiatively target to the HepG2 cells and the liver cancer of rat models expressing AFP,which may help to achieve the specificity of MR imaging in the diagnosis of HCC.

Objective To explore diagnostic value of MR perfusion weighted imaging(PWI)on complications and tumor recurrence in hypopharyngeal and laryngeal cancer after operation and radiotherapy. Methods MR PWI was performed in 31 patients with hypopharyngeal and laryngeal cancer who suffer from tumor recurrence, granulation or infection after operation and radiotherapy. Blood flow (BF), blood volume(BV), mean transit time(MTT) and time to peak (TTP) values were measured in the lesions. Analysis of variance and pair-wise comparison of q test were used for statistical analysis. Results Eleven cases with tumor recurrence,11 case with granulation tissues, 9 cases with infection were confirmed by pathological examinations. Average BF, BV, MTT and TTP values of recurrent tumors were (145.1 ± 29.3)ml · 100 g-1 · min-1,(14.2 ± 3.2)ml · 100 g-1,(5.4 ± 0.6)s,(13.7 ± 1.3)s respectively;Average BF, BV MTT and TTP values of granulation tissues were(109.1±27.4)ml·100 g-1·min-1,(11.1±1.7)ml·100 g-1,(7.7±1.0)s, (19.8 ± 2.1)s respectively;Average BF, BV, MTT and TTP values of infectious tissues were(86.9 ± 7.7)ml · 100 g-1·min-1,(8.8±1.0)ml·100 g-1,(8.0±0.9)s,(19.7±1.3)s respectively. Average BF and BV values of the recurrent tumors group were higher than those of the granulation(q=4.89, 4.64 respectively,P<0.01)and infection group(q=7.52,7.71 respectively,P<0.01)respectively. Average BV values of granulation group was higher than that of the infection group(q=3.31,P<0.05), Average MTT and TTP values of recurrent tumor group were lower than those of the granulation (q=9.38, 12.48 respectively,P<0.01)and infection group(q=9.77, 11.53 respectively,P<0.05). There were no significant difference in average BF, MTT and TTP between the granulation and infection group. Conclusion MR PWI can be helpful in the diagnosis of complications and tumor recurrence in hypopharyngeal and laryngeal cancer after operation and radiotherapy.

Objective To investigate the significance of modified gold nanocages ( GNCs ) in photothermal therapy and radiosensitivity enhancement for murine mammary carcinoma 4T1 cells.Methods A molecule probe, CD44-PEG-GNCs, was constructed on the basis of GNCs.Inductively coupled plasma mass spectrometry ( ICP-MS) and transmission electron microscopy ( TEM) were used to analyze Au uptake by 4T1 cells.The cell counting kit-8( CCK-8) assay was used to determine the impact of the probe on the viability of 4T1 cells.The CCK-8 assay and the Hoechst/PI double staining were used to evaluate the photothermal killing effects of near infrared laser (NIR).The colony forming assay and the Hoechst/PI double staining were used to measure the viability of 4T1 cells after irradiation with 6 MV of X-ray.Results ICP-MS and TEM showed that 4T1 cells had an uptake of a large number of GNCs, in which the number of CD44-PEG-GNCs taken up by 4T1 was 3-4 times larger than that of PEG-GNCs.The cell toxicity assay revealed that in a certain range of concentration, GNCs showed little effect on the viability of 4T1 cells, which was reduced to 81.2%in 48 hours.The CCK-8 assay, the Hoechst/PI double staining, and the colony forming assay showed that after NIR irradiation and radiotherapy, large-scale apoptosis was induced in CD44-PEG-GNCs-contained tumor cells by photothermal therapy combined with radiotherapy, which had substantially better outcomes than other groups.Conclusions The GNC-based molecular probe actively targets 4T1 cells with little cytotoxicity, indicating that it enhances the sensitivity of tumor towards photothermal therapy and radiotherapy.

Objective To investigate the potential value of VEGF-C targeted ultrasmall superparamagnetic particles of iron oxide (USPIO)molecular probe in specific detection of hepatocellular carcinoma (HCC)in a rat model using MRI.Methods The targeted probe was synthesized by conjugating VEGF-C antibody with amino modified USPIO.Cell counting kit-8 assay was conducted to as-certain the probe’s effect on the growth of HepG2 cells.Rat models with HCC were divided into two groups (targeted group with VEGF-C-USPlO and a contrast with USPIO)with 3 rats for each group at random.Pre-and post-contrast enhanced MR imaging with different time points of 0.5,1 and 1.5h was performed with an injection into caudal vein.The signal intensities of the tumor on T2 WI and T2 * WI were measured,and the differences of the signal intensities between pre-and post-enhancements or between both groups were analyzed.The iron particles within the tumors in two groups were confirmed by Prussian blue iron staining.The ex-pression of VEGF-C in HCC was proved by immunohistochemistry.Results The signal intensities of HCC on T2 WI and T2 * WI af-ter VEGF-C-USPI0 injection were decreased obviously with a minimum value at 1 h ,indicating a significant difference (P <0.05). However,those in USPIO group were decreased less without statistical differences (P >0.05).Statistical differences in signal inten-sity on T2 * WI after enhancement between both groups were also showed (P <0.05).Prussian blue staining results showed more iron particles within the tumor tissues in VEGF-C-USPI0 group,whereas less ones in USPIO group.Immunohistochemical results showed that VEGF-C was over expressed in cytoplasm and membrane.Conclusion VEGF-C-USPI0 molecular probes can initiatively target to the liver cancer in rat models with expressed VEGF-C,which may help to achieve the specific MR imaging of HCC,indica-ting a potential of the metastasis.

Objective:To study the differences in angiogenesis and its maturation between the periphery and center. of hepatocellular carcinoma (HCC). Methods:Thirty-one cases proved surgically and pathologically were selected. After surgery, two sections were gotten from the tumor periphery and center. Continuous slices were stained with immunohistochemistry of five antibodies against VEGF, Flk-1, PCNA.The expressions of VEGF,Flk-1, and PCNA, and some vascular parameters were counted including the number, mean area, total area, circumference, diameter, distance between adjacent vessels(DAV), variety index of microvessel and mature vessels. The arterioles , veinlets, mature vessel index and mean perfused fraction (mPF)were also calculated. The differences of the vascular parameters above between the periphery and center were analyzed. Results: The differences in the number, diameter, and variety index of microvessel, the number and total area of mature vessel, the arterioles and the ratio of arteriole or veinlet, mature vessel index and mPF were statistical differences between the periphery and center of the tumor (P

Objective: To evaluate the liver function status in patients with obstructive jaundice using in vivo 31-phosphorus magnetic resonance spectroscopy (31P-MRS). Methods:31P-MRS scan with a single voxel on hepatic parenchyma was carried out in 31 patients with obstructive jaundice and in 40 healthy controls. Intracellular pH value (pHi), and some metabolic parameters including phosphomonoester (PME), phosphodiester (PDE), inorganic phosphate (Pi), ?-ATP, ?-ATP, ?-ATP, lower energetic phosphate (LEP), and the ratios of PME/ATP, Pi/ATP, PME/PDE, PME/Pi, PDE/Pi and PDE/ATP were calculated. Serum markers of liver function including AST, ALT, TBIL, DBIL, IBIL, TP, ALB, GLO, A/G, ALP and GGT were also recorded. The relationship between themwas analyzed. Results: 31P-MRS showed an increase in PME, PDE, PME/ATP, PME/Pi, PDE/ATP and LEP in jaundice patients compared with controls (P

Objective To evaluate the value of 16-slice spiral computed tomography angiography(16SCTA) and reconstruction technique in the diagnosis of vascular diseases. Methods Using 0.75 mm collimation,1mm slice thickness and 0.5mm repitition,16SCTA was performed in 100 patients with suspected vascular diseases.Reconstruction methods were multiple planar reconstruction(MPR),maximum intensity projection(MIP) and volume rendering technique(VRT). Results 65 patients were proved by pathology or DSA in 100 vascular diseases,which included cerebral aneurysm(n=8),brain arteriovenous malformation(AVM,n=2),pulmonary AVM(n=6),pulmonary artery embolism with thrombus of the lower limb vein(n=9),pulmonary sequestration(n=4),coronary artery soft plaque and / or calcification(n=20),aortic aneurysm(n=12),renal artery stenosis(n=3),superior mesenteric artery thrombus(n=2),femoral artery stenosis(n=1),soft tissue hemangioma(n=33).Three reconstruction techniques showed the size,shape and extent of the lesion and displayed the lesion in any directions.VRT could display three-dimensionally the lesion.MPR and MIP could show the thrombus of lesion,MIP and VRT could display the calcification of lesion. Conclusion Application of every 16 SCTA reconstruction technique can display clearly lesion and replace DSA in diagnosis of vascular diseases,and provides another reliable diagnostic method for patients and has clinical importance for treatment.