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Objective:To investigate the effect of different scanning modes, detector width and location in detector on high and low contrast resolution of wide-detector CT image.Methods:The Catphan600 phantom with high and low contrast resolution modules was scanned with GE Revolution CT at the same CTDI vol. The scans were performed with the detector widths of 40, 80 and 160 mm for sequential scanning mode and with the detector width/pitch combinations of 40 mm/0.516, 40 mm/0.984, 80 mm/0.508 and 80 mm/0.992 for spiral scanning mode. The resolution modules were placed at the adjacent region between two sequential scans, central and foot side edge in the longitudinal scanning range seperately. The subjective evaluation of the high and low contrast resolution was performed by two radiologists. Results:The high contrast resolution was 8 LP/cm at adjacent region between two sequential scans with the detector width of 80 mm or 160 mm in sequential scanning mode, and at the pitch of 0.5 in spiral scanning mode, while it was 7 LP/cm for the rest of detector combinations. The distinguishable diameter was 3 mm at 1% low contrast resolution at foot side edge with the detector widths of 80 mm or 160 mm in the sequential scanning mode, and it was 2 mm for all the other conditions. The distinguishable diameter was 2 mm at 1% low contrast resolution with the detector width of 40 mm and pitch 0.516 in the spiral scanning mode and it was worse with the wider detector and larger pitch.Conclusions:For the wide-detector CT, scanning mode, detector width, location in detector and pitches will affect the high and low contrast resolution to some degree. Appropriate selection should be done according to actual needs in clinical practice.
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Objective:To investigate the uncertainty of the dose measurements of superficial organs and the image noise in CT scanning.Methods:GE Revolution CT was used to perform 20 repeated scans on the isolated skull specimen in sequential and helical mode. The chest phantom was scanned for 45 times with the pitch 1.0 and the collimation 80 mm for two scanners (GE Revolution CT, Philips Brilliance iCT) and 40 mm for the Siemens Somatom Definition Flash CT. The volume CT dose index (CTDI vol) was maintained during the above scannings. A dosimeter was used to measure the dose at the position of the right eye lens of the specimen and the center of right breast of the chest phantom. The position of dosimeter sensor remained unchanged. The standard deviation of CT values (image noise) in the air region of cross-sectional images at the center of the sensor reconstructed with lung/soft tissue algorithms were measured. The mean values ( Av), standard deviations ( SD), coefficients of variation ( CV) and relative ranges ( RR) of the dosimetric values and the standard deviations of CT values of 3, 5, 10, 20, 30 and 45 scans were calculated. Pearson and Spearman correlation analysis were used to evaluate the correlation between the dosimetric values and the standard deviations of CT values. Results:The measured dosimetric values of the skull specimen were almost unchanged in the sequential scannings. The relative range of dose in helical mode was 10.67%. The relative ranges of the measured values of the three CT scanners for 45 scans reached 43.83%, 25.31%, and 14.32%. The standard deviations of CT values of the lung/soft tissue images varied greatly and the differences were not completely related to the dosimetric values.Conclusions:The dosimetric values of superficial organs were stable in the sequential scanning mode. The dose measurements of superficial organs and the image noise changed greatly in helical scanning mode.
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Objective:To investigate the effect of organ dose modulation (ODM) technique on reducing the breast radiation dose in chest CT scanning.Methods:In the phantom test, the PBU-2 adult chest module was used. The clinical chest scan protocol was used and three sets of scans performed on the chest module： (1) ODM off group, ODM was not used; (2) ODM part group, ODM was applied only in the breast region； (3) ODM all group, ODM was applied in the whole scan scope. Other scan parameters were same for the three groups, with smart mA applied. The volume CT dose index (CTDI vol) was recorded for all three groups. A long rod ionization chamber was placed in a fixed position in front of the right breast area to measure the breast skin dose (D). The contrast noise ratio (CNR) and the figure of merit (FOM) were measured respectively. In clinical research, 72 female patients who underwent chest CT scanning in Beijing Tongren Hospital Capital Medical University from August to November 2018 were retrospectively recruited. According to the application of ODM, the patients were divided into ODM off group (without ODM, 36 cases) and ODM part group (ODM applied in the breast region, 36 cases). The CTDI vol and the dose length product (DLP) were recorded. CNR, noise of images were measured and calculated, respectively. The image quality was evaluated by subjective evaluation scores. The one way ANOVA analysis was used in comparing the difference of CNR among the 3 groups in module test. As for clinical cases, the independent samples t test was used to compare the difference in CTDI vol, DLP, CNR and the noise between two groups; and the rank-sum test was used for comparison in image quality subjective evaluation. Results:In module test, the radiation dose was highest in ODM off group, and lowest in ODM all group. The CTDI vol were (6.90±0.02), (6.26±0.02) and (5.99±0.02) mGy, and the D values were (9.17±1.01), (8.01±0.92) and (7.58±0.87) mGy for ODM off group, ODM part group and ODM all group respectively. The CNR values of images with soft tissue algorithm reconstruction were highest in ODM off group and lowest in ODM all group, while no statistically significant difference was displayed ( P>0.05). The CNR values of the images with lung algorithm reconstruction showed the same trend, with statistically significant difference among the three groups ( F=154.732, P=0.006). The FOM of the lung and soft tissue algorithm images was maximized when the ODM was partially applied. As for clinical cases, compared with ODM off group, the dose of ODM part group showed significantly decreased, with CTDI vol decreased by 16.12% ( t=2.604, P=0.011), and the DLP decreased by 16.85% ( t=3.293, P=0.002). No significant difference was found in CNR, noise and subjective score by two doctors between two groups ( P>0.05). Conclusion:The application of ODM in chest CT imaging can reduce the radiation dose of breast with simultaneously maintaining the image quality.
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Objective According to the assessment results of Norton Scale at admission, to evaluate the prognostic of Norton Scale on postoperative complications after total hip arthroplasty (THA) in elderly patients, and to guide clinical practice. Methods A prospective study was conducted. Selected the quasi for THA in elderly patients as the research object. The patients were divided into low Norton group(total scale score≤14 points, 28 cases) and high Norton (total scale score≥15 points, 125 cases) according to the Norton Score. Postoperative complications after THA between the two groups were compared. Results The postoperative complications of wound infection, urinary tract infection, urinary retention, bedsore and deep vein thrombosis after THA was 32.1％(9/28), 17.9％(5/28), 10.7％(3/28), 10.7％(3/28), 14.3％(4/28) in low Norton group and 2.4％(3/125), 1.6％(2/125), 1.6％(2/125), 0.8％(1/125), 1.6％(2/125) in high Norton group, and there was significant difference (P<0.05). Logistic regression analysis showed that low Norton were independently associated with postoperative complications (P<0.05), the probability model of judgment after total hip replacement surgery complications accuracy was 86.9％, sensitivity was 96.5％, specificity was 60.0％. Conclusions In addition to predicting pressure ulcer risk, the Norton Scale may be used to predict the incidence of postoperative complications in elderly patients with THA.
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A sensitive and selective method was developed for the separation and characterization of related substances (RSs) in EVT-401 by hyphenated LC–MS techniques. Complete separation of the RSs was achieved with an Inertsil ODS-SP column (250 mm×4.6 mm, 5 μm) by linear gradient elution using a mobile phase consisting of 0.2% formic acid solution, methanol and acetonitrile. EVT-401 was found to be susceptible to acid, alkaline and oxidative stresses, while relatively stable under photolytic and thermal dry stress conditions. Fourteen RSs including six process-related substances and eight degradation products were detected and identified in EVT-401 with positive ESI high-resolution TOF-MS analysis of their parent ions and the corresponding product mass spectra elucidation, and some of them were further verified by chemical synthesis and NMR spectroscopy. The specific LC–MS method developed for separation, identification and characterization of RSs is valuable for EVT-401 manufacturing process optimization and quality control.
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Objective To study the impact on the radiation dose,organ doses of eye lens and thyroid and image quality with different scanning modes in head and neck CT scan.Methods The simulation phantom of head and neck was scanned by using fixed scanning condition (120 kV and 200 mAs),as well as the combinations of automatic tube current modulation (CARE Dose 4D),automatic tube voltage modulation technique (CARE kV) and partial angle scanning mode (X-CARE) respectively.Six kinds of scanning modes were adopted,including 120 kV +200 mAs,120 kV + 200 mAs + X-CARE,CARE Dose 4D + 120 kV,CARE Dose 4D + 120 kV + X-CARE,CARE Dose 4D + CARE kV,CARE Dose 4D + CARE kV + X-CARE.Two thermolumineseece dosimeters (TLDs) were exposed at the skin surface positions of eye lens and thyroid,and the values measured with two TLDs were averaged.The CT dose index volume (CTDIvol) and dose length product (DLP) for every scan were recorded,and the contrast to noise ratio (CNR) in eye lens section and thyroid section were measured.Results The crgan doses of lens and thyroid were 19.8 and 26 mGy at 120 kV and 200 mAs,as well as 13.3 and 22.2 mGv at X-CARE mode.Compared with the manual selection of 120 kV,the combination of CARE kV and CARE Dose 4D made the values of CTDIvol drop from 13.1 to 10.1 mGy,the doses of eye lens and thyroid from 16.6 and 20.8 mGy to 23.7 and 19.9 mGy respectively,while the image quality reducedsignificantly.Compared with CARE Dose 4D + 120 kV,the organ doses of eye lens and thyroid were reduced from 20.8 and 23.7 mGy to 9.6 and 15.1 mGy for with additional X-CARE,while CTDIvol dropped from 13.1 to 9.3 mGy.When the combination of CARE Dose 4D + CARE kV + X-CARE was used,CTDIvol and organ doses were reduced to a minimum,when the CNRs of head and neck were also minimized.Conclusions The scanning mode CARE Dose 4D + 120 kV + X-CARE for head and CARE Dose 4D + CARE kV for neck can effectively reduce the radiation dose while keeping good image quality.When requirements for image quality are not high,CARE Dose 4D + CARE kV + X-CARE mode can be selected to reduce the radiation dose significantly.
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<p><b>OBJECTIVE</b>To investigate the effect of Src kinase inhibitor PP2 on hypoxia/reoxygenation (H/R) injury in rat astrocytes in vitro.</p><p><b>METHODS</b>In vitro cultured rat astrocytes were exposed to hypoxia for 8 h followed by reoxygenation for 24 h with or without pretreatment with PP2 (10 µmol/L) for 24 h before H/R injury. MTT assay and flow cytometry were used to detect the viability and apoptosis of the exposed astrocytes, respectively, and the protein expressions of Src, Bax, and Bcl-2 in the cells were determined using Western blotting.</p><p><b>RESULTS</b>PP2 pretreatment significantly increased the viability and decreased the apoptosis rate of rat astrocytes exposed to H/R injury (P<0.01). Western blotting showed that H/R injury caused increased expression of Src kinase, which was lowered by PP2 pretreatment. The ratio of Bax/bcl-2 in the astrocytes increased after H/R injury, and was significantly decreased by PP2 pretreatment (P<0.01).</p><p><b>CONCLUSION</b>PP2 protects rat astrocytes from H/R injury possibly by inhibiting the expression of Src kinase and activating the anti-apoptotic mechanisms in the cells.</p>
Subject(s)
Animals , Rats , Apoptosis , Astrocytes , Pathology , Cell Hypoxia , Cells, Cultured , Flow Cytometry , Pyrimidines , Pharmacology , src-Family KinasesABSTRACT
Objective To explore the effect of isometric contraction-induced ischemic burden for evoking maximal intrinsic femoral artery collateral circulation. Methods Twenty-four adult New Zealand rabbits weighing (2.0±0.5) kg were subjected to a model of isometric contraction-induced ischemia. An electrode was implanted in the sciatic nerve of the left hind limb for evoking isometric contraction of the gastrocnemius, which blocked local blood flow and induced local ischemia. Femoral artery collateral blood flow (FCBF) was measured using a micro-sphere technique. Results Local blood flow was the lowest at 40% of the maximal isometric contraction (IEmax), and reached plateau at 60% of IEmax. FCBF increased gradually and reached a plateau at 40% of IEmax in the 4th min. After 4 minutes at 40% of IEmax, FCBF had increased to higher than pre-stimulus, peaking in the 2nd minute, and then decreasing gradually to baseline at the 5th minute after reperfusion. It ceased to increase when reperfusion was prolonged to 8 or 10 min. Conclusions The minimal ischemic burden for full obstruction of the femoral artery is 40% of IEmax, and the shortest stimulus duration is 4 min. The maximal FCBF opening duration is no more than 5 min.
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Objective To investigate the effects of tanshinol on the proliferation,apoptosis and NF-?B activation in rat hepatic stellate cells(HSCs) after IL-1? inducement,and to elucidate the anti-fibrotic molecular mechanisms of tanshinol.Methods The rat HSCs was isolated with collagenase in situ liver recirculation perfusion and cultured in vitro.The cells were divided into 5 groups: normal control,IL-1? treatment group(10 ng/ml),and tanshinol group 1,2 and 3.The later 3 groups were pretreated with tanshinol at the concentrations of 0.062 5,0.125 and 0.25 mmol/L respectively followed by 10 ng/ml IL-1? treatment 1 h later.MTT colorimetric assay was used to detect the proliferation of HSCs.AO/EB immunoflurorescence microscopy and combination Annexin-V-FITC/PI double-labelimmunofluorescence with flow cytometer were employed to examine the apoptosis of HSCs.Synthesis and secretion of collagen Ⅲ were detected by the quantitative immunocytochemical assay and ELISA respectively.The amounts of cytoplasm p-I?B? and NF-?B p65,and nuclear NF-?B p65 in HSCs were determined by Western blotting.Immunocytochemical staining and Western blotting were used to observe nuclear translocation of NF-?B p65.Results IL-1? increased the proliferation of HSCs(P