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Objective:To investigate the feasibility of tube potential of 80 kV combined with personalized contrast agent protocol in carotid artery CT angiography (CTA).Methods:A total of 136 consecutive patients undergoing neck CTA were prospectively enrolled in this study. The patients were randomly divided into Groups A, B, C and D. Tube potential of 100 kV and 15 s contrast agent injection protocol was used for Group A (53 cases) as conventional group, while tube voltage of 80 kV and 10 s contrast agent injection protocol was used for Groups B, C and D as experimental groups, with the contrast agent dosages of 20, 25 and 30 ml used according to the body weights of ≤50 kg(Group B, 20 cases), 50-70 kg (Group C, 38 cases), and 70-90 kg (Group D, 25 cases), respectively. The subjective and objective evaluation results of image quality and the effective doses were compared among the four groups.Results:The effective doses in Groups B, C and D were 1.54±0.91, 1.89±1.08 and 2.14±1.27 mSv, respectively, significantly lower than that in Group A [(5.66±0.56) mSv] ( F=169.34, P<0.05). The image quality of four groups met the requirements of clinical diagnosis. No significant differences were found in subjective evaluation and diagnostic efficacy of the four groups ( P>0.05). The CT number of carotid artery, signal-to-noise ratio and contrast-to-noise ratio of the neck region were significantly lower in Groups B, C and D compared with Group A ( F=14.9, 12.94, 14.43, P<0.05). The CT numbers of target carotid vessel were all higher than 250 HU. Conclusions:The scanning protocol of low tube potential (80 kV) combined with 10 s contrast agent injection protocol could not only reduce the doses of radiation and contrast agent, but also preserve the diagnosis effect. Thus, this scanning protocol was feasible and valuable in clinical application.
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Objective We performed a diffusion tensor imaging (DTI) study to explore the value of mode of anisotropy (MO) and other DTI-derived indices in assessing white matter fiber damage with mild to moderate Alzheimer disease (AD) patients. Methods This study was a prospective study. From February 2015 to February 2018, 33 patients with mild to moderate AD according to criteria were prospectively recruited as AD group at the First Affiliated Hospital of Wenzhou Medical University. Twenty healthy age-, sex-matched volunteers were recruited as normoal conctrast (NC) group. All subjects were performed by conventional brain MRI and DTI scans. The MO, anisotropic fraction (FA), mean diffusivity (MD), radial diffusivity (RD) and axial diffusivity (AxD) of white matter fibers were obtained from DTI images after TBSS post-processing. The statistical analyses of DTI indices between AD group and NC group were carried out in Functional MRI Software Library software. Results As compared with NC group, we found 1 cluster with significant decrease FA and increase RD in AD group, the affected fibers involving bilateral anterior thalamic radiation, corticospinal tract, cingulate gyrus, hippocampus, inferior fronto-occipital fasciculus, inferior longitudinal fasciculus, uncinated fasciculus, superior longitudinal fasciculus (P<0.05). The MD value increase(P<0.1) was found to coincide with the decrease of FA and the increase of RD, while no significant increase or decrease in P<0.05. Three clusters of MO increases (P<0.05) accompanying with increases of AxD were found in left anterior limb of internal capsule, bilateral posterior limb of internal capsule, posterior forceps, left centrum semiovale and parietal lobe. Two clusters of MO decreases (P<0.05) accompanying with decreases of FA and increases of RD were found in fornix, forceps, external capsule, centrum semiovale and left frontal lobe. Conclusions The combination of MO with DTI routine tensor indices (FA, RD, MD, AxD) can further reveal the microstructural damage of white matter fibers in AD, especially to crossing-fibers. The abnormalities of MO combined with FA, RD and MD reveal the degeneration of both bundles of crossing-fibers,and the abnormalities of MO combined with AxD reveal that the white matter damage was mainly caused by axon damage of one bundle of cross fibers.
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Objective To assess the influence on radiation dose and image quality of bronchial artery CT angiography for hemoptysis patients with high heart rate and free respiratory with single-cardiac dynamic volumetric scanning using 320-row CT.Methods During October 2016 and May 2017,totally 151 hemoptysis patients with heart rate ≥ 65 bmp and free-breathing were scanned for bronchial artery imaging with prospective ECG-gating 320-detector row dynamic volume CT.The patients were randomly divided into two groups,group A(81 cases) and group B(70 cases).Default multi-cardiac cycle scanning style was used for group A to generate multi-sector images A 1 which were reconstructed corresponding single-sector images A2.Single-cardiac periodic scanning was used to get single-sector images for group B.The effective doses (E) of two scanning types,the quantitative parameters of image quality [vascular CT value,image noise (SD),signal-to-noise ratio (SNR),contrast-to-noise ratio (CNR)] and subjective scoring of group B and A1,A2 were compared.The detection accuracy of the systemic artery-pulmonary circulation shunts was evaluated by ROC curve against digital subtraction angiography (DSA).The measurement data was analyzed by independent sample t test while the grade data was tested by independent sample nonparametric test.Results The median value of radiation dose in group B was significantly lower than that of group A (1.42 mSv vs.3.06 mSv,Z=-8.724,P＜0.05).There were no statistically significant differences in quantitative parameters and subjective scoring points of image quality between group B and group A2 (P＞ 0.05).The median subjective scoring points of group B was 4,which was better than that of group A1 (Z =-10.584,P＜ 0.05).The differences of SD,SNR,CNR betweengroup B and group A1 were statistically significant(t =-0.983,7.898,7.695,P＜0.05),and group B had higher SD,SNR and CNR.There was no significant difference in the mean CT values of the aorta and pulmonary artery between the two groups (P ＞ 0.05).The detection accuracy of the systemic arterypulmonary circulation shunts was moderately high in group B and group A2.The area under the ROC curve (AUC) was 0.891 and 0.864,respectively (Z=7.210,7.430,P＜0.05).The accuracy of group A1 was poor.The area under the ROC curve was 0.626 (Z=2.434,P＜0.05).The sensitivity of group B and groupA2 were 80％ and 76.2％,respectively (P＜0.05),and 28.6％ of group A1 (P＜0.05).Conclusions The 320-row single-cardiac periodic dynamic volume CT can effectively improve the image quality and the detection accuracy of the systemic-pulmonary circulation on CT,and reduce the radiation dose of the bronchial artery CT angiography.
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Objective To investigate the radiation dose to phantoms of thick dense breasts (compression thickness ＞ 65 mm) and the influence of Molybdenum-Rhodium (Mo-Rh) and Wolfram Rhodium (W-Rh)) target-filter combination on image quality in full field digital mammography (FFDM).Methods An aluminium plate was placed on polymethyl methacrylate (PMMA) plates to simulate dense breasts.Two of 68 mm in-depth phantoms were used to simulate photography condition of thick dense breasts with 0.1 and 0.2 mm aluminium plates respectively.The two phantoms were exposed automatically,half-automatically and manually.The parameters were recorded for each exposure including the target-filter(T-F),tube voltage (kV),tube current (mAs),average glandular dose (AGD),entrance surface dose (ESD) and the image quality figure inverse (IQFInv).Pearson correlation and regression was used to analyze the influence of AGD on IQFInv.Paired sample t-test was used to analyze the influence of different target-filters on IQFInv and AGD.Results AGD had a positive correlation with IQFInv (r =0.806-0.953,P ＜ 0.05).For the phantom of 0.1 mm aluminium,when the tube current was fixed at 100 mAs or the tube voltage was fixed at 28 kVp,AGD and IQFInv had statistically significant difference for two target-filters(t =3.162-8.028,P ＜0.05).For the phantom with 0.2 mm aluminium,when the tube current was fixed at 100 mAs under different tube voltage,AGD and IQFInv had statistically significant difference for two target-filters(t =4.768-8.028,P ＜ 0.05);when tube voltage was fixed at 28 kVp under different tube current,AGD had statistically significant difference for two target-filters(t =7.730,P ＜ 0.05),while there was no statistical difference in IQFInv(P ＞ 0.05).In addition,when tube current was 100 mAs,IQFInv had statistically significant difference for two phantoms in W-Rh(t =2.345,P ＜ 0.05).Conclusions W-Rh target-filter combination can achieve lower radiation dose under the guarantee of the image quality compared with Mo-Rh target-filter combination.At the same tube current,W-Rh target-filter combination can provide a better image quality under a relatively high tube voltage.
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Objective To investigate the radiation dose delivered to the patients with dense breasts and the influence of photographic conditions on image quality in full field digital mammography (FFDM).Methods (1) Clinical test:we analyzed the compression thickness of breasts,Target-filter(T-F),voltage current (kV),tube current (mAs),average glandular dose (AGD) and entrance surface dose (ESE) of 100 patients (a total of 370 images,277 images of Molybdenum-Rhodium(Mo-Rh)and 93 images of Wolfram-Rhodium (W-Rh)) who underwent examinations in mode of automatic exposure by FFDM with dense breasts.(2) Phantom experiments:placed the Aluminium plate on different thickness of polymethyl methacrylate (PMMA) plates to simulate the dense breasts.68 mm phantom was used to simulate photographic condition of W-Rh and 58 mm to Mo-Rh.The two groups of dense phantom were exposed automatically and manually.The parameters were recorded for each exposure including the compression thickness of breasts,T-F,kV,mAs,AGD,ESE,the calculation of the ratio between ESE and AGD (ESE/AGD).The image quality figure inverse (IQFInv) was obtained by software.To the clinical test,used multiple factors of variance to analyze the influence of compression thickness and mAs on AGD and ESE,Pearson correlation and regression to analyze the influence of compression thickness on ESE/AGD.To the phantom experiments,used Pearson correlation to analyze the influence of kV and mAs on AGD,ESE and ESE/AGD,single factor of variance to analyze the influence of kV and mAs on IQFInv.Results (1) Clinical test:to Mo-Rh and W-Rh,with the increase of compression thickness,ESE/AGD was increased significantly.Compression thickness had linear relationship with ESE/AGD.Pearson correlation coefficients of W-Rh and Mo-Rh were 0.956 and 0.980,respectively(P＜0.01).The effects of compression thickness and mAs on AGD and ESE were statistically significant (P＜0.05) in the two groups.(2)Phantom experiments:adjusted exposure parameters to the two dense phantoms of W-Rh and Mo-Rh.With the increase of mAs and kV,IQFInv was increased in W-Rh and Mo-Rh.Different mAs and kV were statistically significant (P＜0.05) on IQFInv,mAs and kV had positive correlation with ESE and AGD (P＜0.05),mAs and kV had different correlation with ESE/AGD in the two dense phantoms.Conclusions In mode of automatic exposure by FFDM,choosing W-Rh can achieve relatively high image quality and lower radiation dose.According to the results of phantom experiments,adjusting kV and mAs properly in manual exposure can reduce AGD and ESE effectively and ensure the quality of the image.
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Objective To discuss the influence of the change in ceiling-mounted shield positions on the radiation doses to the first and second operators during percutaneous coronary intervention.Methods In this study,the entrance surface dose (ESD) rates were measured for the first and second operators at 125 cm and 155 cm height on different ceiling-mounted shield positions separately through transradial approach.Measurements were repeated 20 times for each position and T test was used for statistical analysis of dose rate arithmetic mean values.Results For the first operator,the effective dose values were obtained only on left foot position.The ESD rate values at ceiling-mounted shield position close to patient were higher than that close to operators (t125 =46.9,t155 =4.1,P ＜0.05).For the second operator,the ESD rate values on his foot position,right foot position,left anterior oblique position and right anterior oblique position at ceiling-mounted shield position close to the operator,were higher than that close to the patient separately (t125 =11.9,24.4,11.2,2.7,t155 =16.1,2.8,14.4,28.8,P ＜ 0.05).The ESD rate values on head position,left foot position,left head position at ceiling-mounted shield position close to the operator,were lower than that close to the patient (t125 =-4.3,-2.4,-80.4,t155 =-10.2,-6.7,-152.6,P ＜ 0.05).Conclusions The change in the ceiling-mounted shield positions gave rise to change in radiation dose to the operators.The changes in radiation doses caused by the changes in ceiling-mounted shield positions are different in various angiographic positions.Ceiling-mounted shield should be used in a reasonable way in agreement with different positions in percutaneous coronary intervention so as to effectively reduce operators radiation dose.
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Objective To analyze crossed cerebellar diaschisis(CCD) after subacute phase of spontaneous cerebral hemorrhage(SPSCH)and it's relevant factors with whole-brain CT perfusion(CTP) imaging. Methods Eighty-six patients diagnosed with unilateral SPSCH by CT were prospectively enrolled in our study from July 2015 to October 2016. Whole-brain CTP was performed in each patient.Cerebral blood flow(CBF), cerebral blood volume(CBV), mean transit time(MTT)and time-to-peak(TTP) inipsilateral and contralateral cerebellum were manually measured.The asymmetric indexs(AIs) were also calculated. Moreover, the volume of hematoma, the maximumarea of peri-hematomahypoperfusionin CBF and clinical factors(age, gender, time intervals from symptom onset)were analyzed,and NIHSS scores were used to evaluate the neurological status before patient admission, inspection, and discharge.CCD was rated positive when a unilateral supratentorial hematomawas appeared and an accompanying perfusion decrease was showed in the contralateral cerebellum on at least two sequential slices of CTP maps.All the individuals were divided into two groups including CCD-positive groupand CCD-negative group. The perfusion parameters (CBF, CBV, MTT, and TTP)between the contralateral and ipsilateral cerebellum were analyzed by the two-tailed paired t-test in CCD-positive group. The differences in the perfusion and clinical variables between the two groups were analyzed by the independent sample t-test and the Chi-squared test. Therelationships between the AI values and clinical or radiologic variables were assessed with Pearson correlation test. Results We found 35 CCD positive cases and 51 negative cases in the 86 patients.In CCD-positive groups, the perfusion values of cerebellumipsilateral and contralateral to the hematomawere as follows:CBF were (40.88±11.23) vs. (33.91±9.96) ml·100 g-1·min-1, CBV were (3.30±1.18) vs. (2.75±1.13) ml/100 g and TTP were (22.09±3.98) vs. (22.88±4.15) s, respectively, and there was statistical significance (t=10.231,8.223,-2.883,P0.05)was found in hematoma location,hematoma volume, supratentorialhypoperfusion area and NIHSS scores(at admission, inspection)between CCD-positive and negative groups.The AICBF and AITTP showed linear correlation with time intervals in CCD-positive patients(P<0.05). Conclusions CCD is a common phenomenon in patients with SPSCH.Of all the perfusion parameters,CBF abnormalities are more common.The severity of CCD has a certain correlation with time intervals.There is no significant correlation between CCD and the clinical or radiological data(age, NIHSS scores,hematoma volume, and supratentorial hypoperfusion area).
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Objective To evaluate the reliability of CT perfusion parameter values of the normal hepatic segments and neoplasms, obtained with deconvolution (DC) and maximum slope (MS) algorithms. Methods Perfusion parameter values of 111 ROIs in 62 normal hepatic segments and 49 neoplasms derived from 62 CT perfusion studies performed with 320 multi-slice CT, were retrospectively analyzed by two experienced radiologists. BF,BV and PI according to DC and MS algorithms were compared with t paired test, Pearson correlation and Bland-Altman agreement analysis. Interobserver agreement for all perfusion parameters was calculated using intraclass correlation coefficients (ICC). Results Interobserver agreement measured with ICC was very good for all perfusion parameters (≥0.95). BFdc and BVdc exceeded the BFms and BVms in normal hepatic segments and neoplasms (P0.05). Both pairs of perfusion measurements significantly correlated with each other(r>0.9, P<0.01),but the agreement of BF, BV and PI according to DC and MS algorithms was not good. Conclusions CT perfusion values such as BF,BV and PI obtained by DC and MS algorithms correlated significantly with each other, but with poor agreement.
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Objective To evaluate the clinical value of 320-detector CT in interventional treatment of bronchial artery hemoptysis. Methods CTA and DSA images of 30 patients with bronchial artery hemoptysis were retrospectively analyzed.Spatial anatomical characters of the bronchial arteries,such as the type of branches,origin and opening positions of the bronchial arteries were observed and recorded.Results In 30 patients,6 bronchial arteries distribution patterns were found,and the most common type was R1 L1 (43.3%).83 bronchial arteries were identified using CTA,including 38 on the right and 45 on the left.The right bronchial arteries mainly originated from the intercostal artery (52.6%),while the left bronchial arteries mainly from the descending aorta and aortic arch (82.2%).The opening positions of right and left bronchial arteries were mainly located at the right wall of the descending aorta (78.9%),and anterior wall of the descending aorta (62.2%),respectively.When the cacarina of trachea was used as the reference position,the left and right bronchial arteries were mainly located in the range of above 2 cm to below 1 cm from tracheal bifurcation, accounting for 80% and 89.5%,respectively.Compared with DSA,the sensitivity and specificity of CTA were 97.5% and 100%, respectively.Conclusion 320-detector CT can be used to clearly display the distribution patterns,origin and opening positions of bronchial arteries,and especially to find bronchial arteries with ectopic origin.It is possible to apply 320-detector CT in preoperative routine examination and postoperative evaluation of massive hemoptysis.
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Objective To discuss the effect of the bedside shielding protection on the first and second operators against position radiation in percutaneous coronary intervention.Methods The surface entrance dosage rate for the first and second operators at 125 cm height with and without radiation protection shielding (provided separately) were measured.The t-test was used for statistical analysis of arithmetic mean values of dosage rates.And the effect of bedside shielding protection was calculated.Results The position radiation dosage rate at which the first operator exposed was significantly higher than that for the second in the case of no bedside protection (t =97.1-2 263.0,P ＜ 0.05),whereas the dosage rate at which the first operator (except for the left foot position) exposed was significantly lower than that for the second in the case of no bedside protection (t =-80.9-275.1,P ＜ 0.05).The shielding effect of bedside protection on the first and second operators was in the range of 92.26％-99.36％ and 27.83％-97.90％,respectively.Conclusions The bedside protection may effectively reduce position radiation dose to patients and the use of bedside protection changed the trends in the dose distribution in operators' standing region.Attention should be focused on the radiation protection of the second operators in daily work by making full use of bedside protection.
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Objective To study the effects of two different methods of high-pressure injections on imaging quality of synchronous left axillary artery and vein by using volume CT.Methods Forty seven patients who underwent left axillary vein and artery CTA examination study were analyzed retrospectively according to the contrast agent injection scheme and was divided into two groups A and B.Group A of 25 patients used protocol A,adopted clinical routine delay scanning method,via right elbow vein inject contrast medium.Group B of 22 patients used protocol B,adopted artery delayed imaging combined with vein direct imaging method,via right elbow vein,left radial vein inject contrast agent,respectively.Both values of CT and contrast to noise ratio (CNR) of two groups were compared,objective image quality was compared by two blinded readers.Mann Whiteny U test was used.Results The median of CT values for left axillary artery in group A was 151.9 HU.The median of CNR values for left axillary artery in group A was 7.4.The median of CT values for left axillary vein in group A was 116.0 HU.The median of CNR values for left axillary vein in group A was 3.83.The median of CT values for left axillary artery in group B was 348.8 HU.The median of CNR values for left axillary artery in group B was 25.3.The median of CT values for left axillary vein in group B was 497.0 HU.The median of CNR values for left axillary vein in group B was 35.4.Both values of CT and CNR in two groups showed significant difference (Z=-5.735,-5.799,-5.863 and-5.863,P＜0.01).All of the median scores in group B were greater than in group A(P＜0.01).Conclusion The enhancement effect of protocol B in the left axillary arteriovenous synchronous imaging is significantly higher than those of protocol A,and demonstrates clear image quality and clearer anatomic relationship.
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Objective To evaluate the feasibility of optimized scan protocol in whole-brain perfusion imaging with 320-MDCT scanner.Methods Twenty healthy volunteers were randomly divided into control group (13 patients) and test group (7 patients).The standard perfusion scan protocol (collecting 19 volumes)was applied in control group.The optimized perfusion CT scan protocol(collecting ll volumes)formulated by reducing scanning phases reasonably and changing the collection intervals was applied in test group.The regions of interest(ROI) with area of(20 ± 2)mm2 were located in the bilateral frontal white matter,parietal white matter,centrum semiovate,basal ganglia,occipital lobe and cerebellum.Bilateral perfusion values from ROI were measured,including cerebral blood volume(CBV),mean transit time (TTP),cerebral blood flow (CBF),mean transit time (MTT) and delay time (DT).Results Dose length product (DLP)and effective dose (ED)in optimized protocol were decreased 42.02％ as compared to control group.Every relative perfusion value of both sides from both groups were not statistically significant (P ＞ 0.05).Every relative perfusion parameters from individual territory in both groups showed no significant differences (P ＞ 0.05).Conclusions Using the optimized scan protocol,we could obtain the same whole-brain perfusion values could be obtained with the default standard protocol and less radiation dose.
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Objective To compare the difference of entrance dose between CR and amorphous silocon DR system in chest imaging, and to discuss their optimum exposure dose. Methods For CR and DR, different entrance dose was measured by dosimeter in chest phantom. The value of IQFinv was analyzed by CDRAD2. 0 software. Image quality difference between CR and DR was assessed by group t-test. The relationship between image quality and entrance dose was tested by using Pearson correlation analysis. The best IQFinv values in CR and DR system were achieved via ROC curve analysis, and the exposure dose was then calculated. Results There were direct correlation values between entrance dose and the value of IQFinv in CR and DR system, respectively( r =0. 893 ,0. 848 ,P < 0. 01 ) . The linear regression equation for DR was IQFinv =0. 0050 +3. 359, and for CR was IQFinv =0. 005D + I. 651 , where D was entrance dose. The difference of IQFinv value between CR and DR was significant(t = 5. 455 ,P < 0. 05). The best IQFinv value of the two groups from ROC analysis was 3.55. Conclusions With the entrance dose increased, the detection ability of contrast-detail was elevated in the two digital radiography systems. With equal entrance dose, the detection ability of DR in contrast-detail was superior to CR. With equal image quality, DR obviously decreased the radiation dose to the patients.
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Objective To evaluate the diagnostic value of multi-slice thrce-dimensional computed tomographic angiography(MS-CTA) with volume rendering(VR) for Moyamoya disease.Methods MS-CTA of 25 patients with Moyamoya disease verified by DSA were restrospectively analyzed.Source images were got by GE Lightspeed pro scanner.VR was adopted to reconstruct 3D images in all cases.Results Of 25 CT precontrast,13,12 cases showed infarction and hemorrhage respectively,while 11 cases had dialated vessels in thalamus-basal ganglia region on CT.Accuracy of stenosis or occlusion of the bifurcation of ICA, proximal portion of the ACA or MCA was 88.0% (22/25) by MS-CTA.MS-CTA overestimated the degree of stenosis,MS-CTA misdiagnosed 3 cases(12.0%)with stenosis to occlusion.MS-CTA showed fewer small Moyamoya vessels than DSA.MS-CTA only demonstrated 6 cases(25.0%)with collateral vessels.Conclusion CT is still the conventional method for detecting secondary lesions to Moyamoya disease.CT and MS-CTA can accurately diagnose Moyamoya disease.
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Objective To evaluate the value of spiral CT volume reconstruetion(VR) technique in high complex anal fistula fistulography. Methods To analyze retrospectively internal openings and secondary tracts of 35 eases with high complex anal fistula verified by operation and follow-up above 3 months with VR,and compared with operation and outcome of follow-up. Results In 35 eases with high complex anal fistula, for detection of the presence of internal openings ,VR has a sensitivity of 72.7% ,a specificity of 100% ,a accuracy of 74.3% ,a positive predictive value of 100% ,and a negative predictive value of 18.1%. Secondary tracts have a sensitivity of 93.8% ,a specificity of 100.0% ,a accuracy of 94.6% ,a positive predictive value of 100.0% ,and a negative predictive value of 72.7%. Conclusion VR can demonstrate the 3D shape of fistula and is reliable in the diagnosis of internal openings and sec-ondary ducts, and is very valuable in the analysis of high complex anal fistula fistulography.
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According to the characteristics of our hospital,we establish a PACS/RIS system by adopting individual adaptive compartments and design,and study the net connection methods,key technique as well as the application value of the PACS/RIS system.As a result,PACS/RIS system enables the interchange of images among different models,brings about the centralized storage,the transference and process of remote images,and accomplishes the digitalization of registration and reporting.It optimizes the work flow for the radiography department.