Objective To assess the value of dual-source computed tomography angiography (DSCTA)in detecting intracranial aneurysms by comparing with conventional and three-dimensional DSA.Methods In this study,95 patients with subarachnoid hemorrhage(SAH)underwent both DSCTA and DSA examination.The detection rate,size,and ratio of the neck to the dome(N/D ratio)of the aneurysrns were evaluated.Statistical analysis was performed using a paired sample Student's t-test for the comparisons of the value of N/D and 2 Related Samples test for long axis.Results A total of 67 aneurysms in 63 patients at DSA and 64 aneurysms in 60 patients at DSCTA were detected,respectively;whereas no aneurysm was detected in 32 patients at DSA.Compared with DSA,the overall sensitivity.specificity,positive predictive value,and negative predictive value of DSCTA on a per-aneurysm basis were 94.2%,100.0%,100.0%,and 91.4%,respectively.For the aneurysms larger than 3 mm,the sensitivity and specificity of DSCTA in detecting intracranial aneurysms were equal to those of DSA:For aneurysms smaller than 3 mm,however,the sensitivity and specificity of DSCTA is 80.0% and 100.0%.The N/D ratio for DSA and DSC:TA was 0.46±0.14 and 0.51±0.18.respectively,and the median of long axis was 4.9 mm and 4.8 mm.respectively.There was no significant difierence in the N/D ratio(t=3.20;P＞0.05)and the long axis(Z=-1.309;P＞0.05)between DSA and DSCT.Condusions Compared with conventional and three-dimensional digital subtraction angiography,DSCTA has high sensitivity and specificity in the detection of intracranial aneurysms,especially for detection of snlall aneurysnm(＜3 mm).It can be used as a routine screening technique.

Objective To assess the clinical value of dual-energy intracranial CT angiography (CTA).Methods Forty-one patients suspected of intracranial vascular diseases underwent dual-energy intracranial CT angiography, and 41 patients who underwent conventional subtraction CT were enrolled as the control group.Image quality of intracranial and skull base vessels and radiation dose between dual-energy CTA and conventional subtraction CTA were compared using two independent sample nonparametrie test and independent-samples t test, respectively.Prevalence and size of lesions detected by dual-energy CTA and digital subtraction CTA were compared using paired-samples t test and Spearman correlative analysis. Results The percentage of image quality scored 5 was 70.7% (29/41) for dual-energy CTA and 75.6% (31/41) for conventional subtraction CTA.There was no significant difference between the two groups(Z= -0.455, P=0.650).Image quality of vessels at the skull base in conventional subtraction CTA was superior to that in dual-energy CTA, especially for the petrosal and syphon segment (Z=-4.087, P= 0.000).Radiation exposure of dual energy CTA and conventional CTA were (396.54±17.43) and (1090.95±114.29) mGy · cm respectively.Radiation exposure was decreased by 64% (t=-38.52, P=0.000) by dual energy CTA compared with conventional subtraction CTA.Out of the 41 patients,19 patients were diagnosed as intracranial aneurysm, 2 patients as arteriovenous malformation (AVM), 3 patients with Moya-moya's disease, and the remaining 17 patients with negative results.Nine patients with intracranial aneurysm, 2 patients with AVM, 3 patients with Moya-moya's disease, and 2 patients with negative findings underwent DSA or operation, with concordant findings from both techniques.Diameter of aneurysm neck, long axis and minor axis by dual-energy CTA was (2.90±1.61), (5.23±1.68) and (3.83±1.69) nun, respectively; Diameter of aneurysm neck, long axis and minor axis by DSA was (2.95±1.71), (5.10±1.60) ,(3.83±1.65) nan,respectively.There was no significant difference for the diameters of aneurysm between dual energy CTA and DSA ((t=-0.734,1.936,0.12.5 respectively, P=0.482,0.085,0.903 respectively), and good correlation was found between diameter measurements using the two techniques(r=0.964,0.976,0.973, respectively, all P=0.000) Conclusions Compared with conventional subtraction CTA, dual energy CTA has good image quality for intracranial vessels; however, image quality of the skull base vessels is worse, especially for the petrosal and syphon segment.Dual energy CTA has decreased radiation dose and a high diagnostic accuracy, being a practical imaging madality for diagnosis of intracranial vascular lesions.

Objective To evaluate the value of dual energy CT with Lung Vessels application in diagnosing pulmonary embolism (PE) of children.Methods Forty-seven patients with nephrotic syndrome and aged ≤ 18 years old (32 male,15 female,mean age 15 years) underwent dual-energy CT pulmonary angiography (CTPA).Two radiologists recorded the presence or absence of emboli and counted the clots on a per-patient and per-lobe basis with Lung Vessels,respectively.With conventional CTPA as reference standard,sensitivity,specificity,positive predictive value (PPV),negative predictive value (NPV) of Lung Vessels application to detect PE were computed for two readers.Inter-reader agreement was also calculated.Results Conventional CTPA detected 51 clots in 35 lung lobes in 13 patients,giving PE incidence was 27.6％ (13/47) for this cohort.On a per-patient basis,readers 1 and 2 detected 25 and 21 patients with PE with Lung Vessels,corresponding to sensitivities,specificities,PPVs,and NPVs of 100.0％ (13/13),58.6％ (17/29),43.3％ (13/30),100.0％ (17/17) and 100.0％ (13/13),76.5％ (21/29),50.0％ (13/26),100.0％ (21/21),respectively.On a per-lung lobe basis,readers 1 and 2 detected 74 and 63 clots with Lung Vessels,respectively,corresponding to sensitivities,specificities,PPVs,and NPVs of 94.3％ (33/35),79.5％ (159/200),44.6％ (33/74),98.7％ (159/161) and 97.1％ (34/36),85.5％ (171/200),54.0％ (34/63),98.8％ (171/173),respectively.On a per-clot basis,134 and 105 clots were detected with Lung Vessels application,corresponding to sensitivities,specificities,PPVs,and NPVs for DECT of 96.1％ (49/51),64.9％ (159/245),36.3％ (49/135),98.7％ (159/161) and94.1％ (48/51),75.0％ (171/228),45.7％ (48/105),98.3％ (171/174)for readers 1 and 2,respectively.Excellent or good inter-reader agreement was observed on a per-patient,per-lobe and per-clot basis (Kappa =0.828,0.859,0.695 ; all P ＜ 0.01).Conclusions Dual-energyCT with Lung Vessels application has a high sensitivity and negative predictive value for PE detection in children.More clots are detected with Lung Vessels application than conventional CTPA,which deserve further investigation.

Objective To assess the feasibility, safety, and efficacy of balloon disruption of thrombus by using a deflated balloon catheter combined with intraarterial thrombolysis for the treatment of acute middle cerebral artery(MCA) occlusion. Methods Five consecutive patients with acute MCA occlusion underwent balloon disruption combined with intra-arterial thrombolysis. The microballoon was inflated in the distal carotid artery and then deflated and advanced just distal to the occlusion site in the MCA. Thereafter, intra-arterial thrombolysis of the MCA was applied and the maximum dosage of urokinase was 500,000 U. Results Complete recanalization was achieved in 3 patients and partial recanalization in 2. All patients got favourable clinical outcome. There was no major intracerebral hemorrhage. Conclusion The penetration of the MCA with a deflated balloon catheter combined with an intra-arterial thrombolysis may be a safe and effective treatment for acute ischemic stroke.

Objective To study the potential of functional MRI (fMRI) during passive finger extension (FE) for predicting the motor function recovery of hemiplegic stroke survivors.Methods Nineteen survivors of a 1st cerebral infarction in the non-M1 cortex with complete paralysis on one side were selected for study.Within 1 week after the stroke,fMRI was performed while one of the patient's paralyzed fingers was passively flexed and extended.fMRI signals were acquired from the sensorimotor cortex (SMC),the supplementary motor area (SMA) and the premotor area (PM).Fugl-Meyer (FM) scores of arm motor function were recorded one week,one month and three months after the stroke.Results The early fMRI results were used to classify cortex activation performances as type Ⅰ (activation mainly on the affected side,but SMC and SMA activated bilaterally),type Ⅱ (activation of the SMC and SMA only on the affected side) or type Ⅲ (only activation of the SMC on the affected side).At one week after stroke the average FM scores of the three groups were not significantly different.At one month the three average FM scores were 47.1 ± 5.5 points,36 ±6.7 points and 11.2 ± 3.1 points,for groups Ⅰ,Ⅱ and Ⅲ respectively,each significantly different from the others.At three months the average FM ratings of groups Ⅰ (61.1 ± 3.8 points) and Ⅱ (59 ± 5.2 points) were not significantly different,but both were significantly higher than the average score of group Ⅲ (10.8 ± 5.6 points).Conclusion The early stage fMRI characteristics of hemiplegic patients can be used for predicting motor outcomes.

Pancreatic cancer is a commonly malignant gastrointestinal tumor with an significantly increasing incidence.Those patients without nonspecific symptoms at early stage had mostly lost the opportunity of surgical therapy when pancreatic cancer was detected at advanced stage,and its prognosis is poor.Therefore,it is rather important to improve the early diagnosis of pancreatic cancer.In recent years,proteomics is developing rapidly.Proteomics technologies have been widely used in clinical research.Using proteomics technology screening pancreatic cancer tumor markers becomes the research focus,thus we try to find a kind of or a group of pancreatic tumor markers,so as to improve the diagnosis of pancreatic cancer.

Objective To evaluate the clinical values of dual energy lung perfusion using dual-source CT. Methods Fifty-four patients who underwent chest contrast-enhanced CT were included in this study from May to August in 2007. Dual energy CT scanning was performed in all patients. The patients were divided into four groups: normal group, exudation lesion group, mass lesion group, and pulmonary embolism group. Imaging appearances of dual energy CT perfusion in four groups were analyzed. Results Dual energy CT showed symmetrical homogeneous perfusion in healthy subjects (n = 14), exudation lesions (n =10) appeared as low perfusion, In mass lesions (n =27), peripheral masses presented as local perfusion defect, central masses appeared as segmental perfusion defect because of the involvement of hilar vessels,and pulmonary embolism (n = 3) appeared as perfusion defect in corresponding pulmonary segment.Conclusion Dual energy CT scanning can be used to show the pulmonary perfusion status and assess the pulmonary perfusion abnormalities in central lung cancer and pulmonary embolism.

ObjectiveTo investigate the feasibility and accuracy of dual energy CT (DECT) in detecting acute myocardial ischemic reperfusion injury in a swine model.Methods Acute myocardial ischemic reperfusion injury model was made by ligaturing the left anterior descending coronary artery (LAD)or the first diagonal artery ( D1 ) of swine heart,the first-pass contrast enhanced DECT was performed.And then pigs were sacrificed,and the hearts were removed,triphenyhetrazolium chloride staining was performed.The CT numbers of non-ischemic and ischemic regions were measured.In the short axis of the left ventricle,the ventricular wall was divided into 17 segments for analysis,segments with myocardial perfusion defect in DECT myocardial iodine maps,DECT ( 140,100 kV,weighted average 120 kV) were determined and compared with histopathology.The sensitivity,specificity and inter-modality agreement of DECT in detecting myocardial injury were calculated.One-way ANOVA test was used to analyze the differences between the CT number and weight of infracted myocardium measured on DECT at 140,100 kV,weighted average 120 kV in ischemic and normal regions.ResultsPartial sparse or defective perfusion in the apical anterior and septal wall were demonstrated in DECT myocardial iodine maps.The CT number of injured myocardium was significantly lower than that of normal myocardium at 140,100 kV,weighted average 120 kV.The sensitivity,specificity of DECT myocardial iodine maps were 85.2％ (23/27),86.2％ (94/109),and Kappa value was 0.62,the sensitivity,specificity at 140 kV were 88.9％ (24/27),92.7％ (101/109),and Kappa value was 0.76,the sensitivity,specificity at 100 kV were 85.2％(23/27),89.0％ (97/109),and Kappa value was 0.67,the sensitivity,specificity at weighted average 120 kV were 88.9％ (24/27),91.7％ ( 100/109),and Kappa value was 0.74.There were no significant differences between the weight of infracted myocardium measured on DECT at 140,100 kV,weighted average 120 kV and histopathological results ( F =0.419,P =0.741 ).ConclusionDECT myocardial iodine maps can detect acute myocardial ischemic reperfusion injury in a swine model and have a good correlation with histopathology.

ObjectiveTo evaluate the image quality of displaying the pulmonary artery and pulmonary emboli at different tube voltages and find the optimal tube voltage.MethodsSixty-six patients underwent contrast-enhanced dual energy CT pulmonary angiography (CTPA) from August 2007 to February 2010.Data obtained with 80 kVp,weighted average 120 kVp,and 140 kVp were divided into group Ⅰ,Ⅱ,and Ⅲ respectively.CT value of pulmonary artery ( grade 1—4),emboli,and muscles were measured.Corresponding signal to noise ratio (SNR) and contrast to noise ratio (CNR) were calculated.One-way ANOVA analysis and Friedman test were used to analyze statistical significance among these values.Image quality of CTPA from these three groups was assessed.The inter-reader agreement of image quality was performed by kappa test.ResultsCT value of branch 1 to 4 of ptlmonary artery was (446 ± 140) HU,(433±130) HU,(411 ±138) HU,and (392±127) HU in group Ⅰ,(303±91) HU,(290±85) HU,(276±86) HU,and (263 ±85) HU in group Ⅱ,and (244 ±70) HU,(230 ±63) HU,(216 ±72) HU,and (205 ±68) HU in group Ⅲ.There was significant difference for CT values (P ＜0.01) among three groups.CT value of pulmonary artery in 80 kVp images was higher than 140 kyp and 120 Kvp.On quantitative analysis of 37 patients,CNR value of pulmonary clots was 8.3 ± 3.3,8.0 ± 2.9,and 5.6 ± 2.2 in group Ⅰ,Ⅱ,and ⅢⅢ,respectively.CNR values of pulmonary clots in 80 kVp images and 120 kVp images were higher than that in 140 kVp (P ＜0.01 ).There was no statistical difference for image quality of CTPA among the three groups ( P ＞ 0.05 ).Agreement of image quality of CTPA derived from 80 kVp (kappa value =0.789,P ＜0.01 ) was superior to that of 120 kVp (kappa value =0.652,P ＜0.01 ) and 140 kVp ( kappa value = 0.509,P ＜ 0.01 ).Conclusions CT value of pulmonary artery in 80 kVp images was higher than that of weighted average 120 kVp and 140 kVp,and the image quality and CNR was comparable with that of weighted average 120 kVp images.This tube voltage ( 80 kVp) is optimal for CT pulmonary angiography in the evaluation of patients with suspected pulmonary embolism.

Objective To evaluate monoenergetic imaging of dual energy CT in the visualization of metal fixation of factures. Methods In total, 29 patients with factures underwent 36 metal fixations,including 11 external fixations implanting in tibiofibula (n = 11 ) and 25 internal fixations (cervical spine,n=10; lumbar spine, n=4; tibiofibula, n=8; radial bone, n=3). They were recruited into this study.After dual energy CT scan, monoenergetic software was used to post-process with the following 6 photon energies: 40, 70, 100, 130, 160, 190 keV. Two radiologists evaluated and rated the reformatted images with 6 different photon energies and average weighted 120 kV images according to the following 4-score scale. Score 1: nonassessable, with marked artifact; score 2: assessable, moderate artifact; score 3: good,mild artifact, good visualization of bony structures; score 4: excellent, no artifact. Kruskal-Wallis was used to perform statistical analysis of image quality for total fixations, external and internal fixations with various selective kev settings and average weighted 120 kV. Results For total fixations, monoenergetic imaging of dual energy CT has 25 fixations with score 3 and 4, but 120 kV has only 4 fixations with score 3 and 4.Monoenergetic imaging of dual energy CT improved image quality of fractures with metal fixation compared to average weighted 120 kV images ( F = 116. 487, P ＜0. 01 ). Images of 130 kev had the best image quality for external metal fixation (9 fixations with score 3 and 4, F = 60. 902, P ＜ 0. 01), while 70 kev was best for internal metal fixation ( F = 122. 149, P ＜ 0. 01). Conclusions Monoenergetic imaging of dual energy CT improves image quality of fractures with metal fixation. Reformatted images at 70 keV and 130 keV havethe optimal image quality for internal and external metal fixation, respectively.