Objective To apply a non-invasive and feasible method for the quantification of local wall shear stress (WSS) in vivo using magnetic resonance imaging. Methods The fight common carotid artery of a young healthy male volunteer was examined using cine phase-contrast MR sequence. The cross- sectional area, average flow velocity, maximum velocity and flow rate were obtained. Three dimensional paraboloid model was applied to measure WSS value at common carotid artery. Results The mean/peak WSS was (0.75±0.41)N/m2 for the common carotid artery; The mean (range) velocity was (23.4± 12.0) cm/s; The mean (range) luminal vessel area was (32.2±2.9) mm2; The blood flow rate was (7.8±4. 6) ml/s; Conclusion WSS's magnitude, distribution and changes can be determined by MR imaging combining with the three-dimensional paraboloid method.

English training is important for young doctors＇ career development in general hospital.The stagewise English training mode of Beijing Tiantan Hospital of Capital Medical University was introduced.By summarizing the experience of five years trial,viewpoints were brought forward that hospital English training in radiological department of general hospital should adopt a stagewise mode,create an English communication atmosphere,show the special feature of department and combine with clinical daily work.

Objective To study the effect of age on the hemodynamics of common carotid artery. Methods 47 healthy volunteers werestudied. Wall shear stress (WSS) values localized at common carotid artery 2 cm below the bifurcation were calculated with cine phase-contrastMR imaging combined three-dimensional paraboloid (3DP) model. On the spatial distribution, common carotid artery wall was dividedinto 24 equal parts. Calculate the mean WSS in a cardiac cycle on each part, and choose the minimal WSS value. Then the effects of age onthe average WSS and minimal WSS were observed. Results Total 94 common carotid arteries of 47 health volunteers were examined, inwhich 9 carotid arteries in 9 volunteers were excluded because of uninterpretable high-resolution MRI findings or volunteer's intolerance forthe detection. In the remaining 85 common carotid arteries, the average WSS and the minimal WSS during a cardiac cycle on the spatial distributionwere (7.45±2.12) dyne/cm2 and (5.98±1.93) dyne/cm2 respectively. Both average WSS and minimal WSS were negative correlatedwith age (P<0.05). Conclusion With the age increased, mean WSS and minimal WSS on the spatial distribution of common carotid arterydecreased.

Objective To evaluate the shear stiffness of brain by MR elastography (MRE) in healthy Chinese volunteers and to assess the association between the cerebral shear stiffness and age. Methods Brain MRE studies were performed on 105 healthy volunteers. The shear stiffness of brain parencham was measured by local frequency estimation (LFE) algorithm. The differences of the shear stiffness between white matter(WM) and grey matter(GM) were analyzed by independent sample t test; the differences of brain parenchyma shear stiffness between male and female were estimated by independent sample t test. Spearman test was used to analyze the correlation between age and the shear stiffness of parenchyma; the volunteers were divided into two groups (age ≤ 40 and age > 40) and the correlation between age and shear stiffness of parencbyma in each group were analyzed separately. Results The shear stiffness of whiter matter [(23.1±5.7) kPa] was higher than that of grey matter[(11.3±2.6) kPa], and the difference was significant (t = 19.34, P < 0.01). In male, the shear stiffness of WM and GM was (23.4±5.8) kPa and (11.4±2.8) kPa respectively; while in female, it was (22.8±5.6) kPa and (11.1±2.5) kPa respectively. No sex differences were found in the stiffness of white matter or gray matter (t = - 0.534, - 0.606, P > 0.05). An age-dependent trend was observed in the stiffness of grey matter(r =0.315, P < 0.01),while not in whiter matter (r = 0.183, P > 0.05). When the shear stiffness of subjects no more than 40 years old was analysed, the age-dependent trend of shear stiffness was found both in white matter and gray matter(r = 0.251,0.235, P < 0.05); While in subjects over 40 years old, the age-dependent rend of shear stiffness was not found in white matter or gray matter(r = 0.181, - 0.001, P > 0.05). Conclusions The shear stiffness of WM is significantly higher than that of GM. No obvious sex difference was found in the stiffness of brain parenchyma. The shear stiffness of GM increases with age; the age-related increase of shear stiffness of WM was only found in subjects under 40 years old.

time (r = 0. 070, -0.003, -0. 195,0. 177,P 0.05). Conclusions Compared with omnivore's, the shear stiffness of brain parenehyma was lower in vegetarians. The shear stiffness of brain parenchyma may be affected by the diet.

Objective To investigate the diagnostic value of CTP-SI in acute stroke less than 9 hours.Methods In present study."one-stop shop"CT examination were performed in 34 patients with symptoms of acute stroke in le88 than 9 hours.We divided patients into two groups according to with and without delayed perfusion on CTP-SI.and compared ASPECTS (Alberta Stroke Program Early CT Score Study)scores on non-contrast CT(NCCT),arterial phase CTP-SI,venous phase CTP-SI with follow-up imaging.The ASPECTS were analyzed on arterial phase CTP-SI and veIlous phase CTP-SI using Wilcoxon rank-sum test.then compared with the follow up imaging ASPECTS using multiple linear regression.Results The median(min-max)scores of ASPECTS on NCCT,arterial phase CTP-SI,venous phase CTP-SI and follow-up imaging were 9.0(6.0-10.0),6.5(1.0-8.0),8.0(3.0-10.0)and 7.0(0-10.0)in group with delayed perfusion,respectively,and 9.0(1.0-10.0),8.5(1.0-10.0),8.5(1.0-10.0)and 8.0 (0～10.0)in group without delayed perfusion respectively.ASPECTs scores measured on arterial phase CTP-SI did not differ from venous phase CTP-SI in group without delayed perfusion ( Z = - 1.00, P =0.317), while there was significant difference in group with delayed perfusion (Z = -3.08, P = 0.002 ).There were significant correlation with ASPECTS scores measured on NCCT, arterial phase CTP-SI and venous phase CTP-SI to follow-up imaging ASPECTS (r =0.899,0.926,0.928,P ＜0.01 ) in group without delayed perfusion; ASPECTS measured in venous phase CTP-SI showed the best correlation to follow-up imaging ASPECTS (r = 0.762, P = 0.004) in group with delayed perfusion.Multiple linear regression showed that the correlation in only venous phase CTP-SI with foUow-up imaging ASPECTS was statistically significant:in group without delayed perfusion, Beta = 0.966, P ＜ 0.001 ; in group with delayed perfusion,Beta = 0.765, P = 0.004. Conclusion Presence of delayed porfusion in CTP-SI is quite important in identifying ischemic penumbra, which plays a critical role in imaging-guided thrombolytie therapy.

OBJECTIVETo assess the value of detecting the compositional features of carotid atherosclerotic plaques by 3.0T high resolution magnetic resonance imaging (MRI) in patients with coronary artery disease (CAD).

METHODSConsecutive 104 patients with coronary atherosclerosis confirmed by coronary angiography were prospectively recruited from January 2013 to January 2015 in Tiantan hospital. All patients were imaged with 3.0T high resolution MRI system. After exclusion patients with poor image quality, 97 patients were divided into 3 groups according to the degree of coronary artery stenosis: coronary atherosclerosis group (coronary stenosis between 1%-49%, n=16); single-vessel lesion group (single vessel lesion with stenosis between 50%-100%, n=48); multi-vessel lesion group (two or three vessel lesions with stenosis between 50%-100% or left main stem disease, n=33). The prevalence of total carotid plaque, calcified plaque, lipid-rich necrotic core, intra-plaque hemorrhage, plaque ulcer and rupture were compared among 3 groups.

RESULTSThe prevalence of total carotid plaque (81.3%(13/16), 72.9%(35/48), and 93.9%(31/33)) and calcified plaque (50.0%(8/16), 35.4%(17/48), and 42.4%(14/33)) were similar among the 3 groups (both P>0.05). The prevalence of carotid lipid-rich necrotic core in coronary atherosclerosis group was significantly lower than in single-vessel lesion group (18.8%(3/16) vs. 64.6%(31/48), P<0.01) and multi-vessel lesion group(18.8%(3/16) vs. 69.7%(23/33), P<0.01), but there was no significant difference between single-vessel lesion group and multi-vessel lesion group(P>0.05). Intra-plaque hemorrhage was detected in 2 patients of multi-vessel lesion group. There was no plaque ulcer or rupture in this cohort.

CONCLUSIONCarotid plaque features are associated with the severity of coronary atherosclerosis in CAD patients.

OBJECTIVE: To assess the practical and health economical values of non-invasive prenatal test (NIPT) in Changsha Municipal Public Welfare Program. METHODS: A retrospective analysis was carried out on 149 165 women undergoing NIPT test from April 9, 2018 to December 31, 2019. For pregnant women with high risks, invasive prenatal diagnosis and follow-up of pregnancy outcome were conducted. The cost-benefit of NIPT for Down syndrome was analyzed. RESULTS: NIPT was carried out for 149 165 pregnant women and succeeded in 148 749 cases (99.72%), for which outcome were available in 148 538 (99.86%). 90% of pregnant women from the region accepted the screening with NIPT. 415 (0.27%) were diagnosed as high risk. Among these, 381 (91.81%) accepted amniocentesis, which led to the diagnosis of 212 cases of trisomy 21 (PPV=85.14%), 41 cases with trisomy 18 (PPV=48.81%) and 10 cases with trisomy 13 (PPV=20.83%). The sensitivity and specificity of NIPT for trisomy 21, trisomy 18 and trisomy 13 were (97.70%, 99.98%), (97.62%, 9.97%) and (100%, 99.97%), respectively. In addition, 213 and 30 cases were diagnosed with sex chromosomal aneuploidies (PPV=46.2%) and other autosomal anomalies (PPV=16.57%), respectively. For Down syndrome screening, the cost and benefit of the project was 120.79 million yuan and 1,056.95 million yuan, respectively. The cost-benefit ratio was 1: 8.75, and safety index was 0.0035. CONCLUSION NIPT is a highly accurate screening test for trisomy 21, which was followed by trisomy 18 and sex chromosomal aneuploidies, while it was less accurate for other autosomal aneuploidies. The application of NIPT screening has a high health economical value.
Aneuploidy ; Cost-Benefit Analysis ; Female ; Humans ; Noninvasive Prenatal Testing ; Pregnancy ; Retrospective Studies ; Trisomy 18 Syndrome/genetics*

Objective To analyze the correlation between smoking and occurrence of intracranial artery stenosis.Methods From June 2015 to May 2016,a total of 10 711 inpatients with transient ischemic attack (TIA) or ischemic stroke from 20 basel hospitals of nationwide were enrolled using a cross-sectional study,76 patients with unknown smoking and smoking cessation years were excluded.Finally,a total of 10 635 patients were enrolled.Transcranial color coded sonography and/or transcranial Doppler were used evaluate the intracranial artery stenosis lesions.The basic risk factors for cerebrovascular disease (age,sex,smoking and smoking years,whether smoking cessation and years,hypertension,diabetes,hyperlipidemia,atrial fibrillation,and family history of stroke) were recorded.According to the different smoking years,the smoking years were divided into five groups:non-smoking,smoking time ≤10-year,11 to 20-year,21 to 30-year,and >30-year groups for trend chi square test.According to the different smoking cessation years in the smokers,the smoking cessation years were divided into four groups:non-cessation,cessation time 1 to 10-year,11 to 20-year,and >20-year groups for trend chi square test.The effects of different smoking years and different smoking cessation years on the occurrence of intracranial arterial stenosis were analyzed.Results The incidence of intracranial artery stenosis in the smokers (40.4%[1 433/3 547]) was significantly higher than that in the non-smoking patients (29.4%[2 085/7 088]).There was significant difference (χ2=128.850,P<0.01),and the incidence of cerebral infarction in the smokers (91.6%[3 250/3 547]) was significantly higher than the non-smokers (85.0%[6 027/7 088]).There was significant difference (χ2=92.328,P<0.01).Smoking was an independent risk factor for intracranial artery stenosis (OR,1.603;95%CI 1.456-1.765;P<0.01).With the increase of smoking years,the detection rate of intracranial arterial stenosis increased gradually (trend χ2=115.437,P<0.01).Whether giving up smoking had no significant effect on the incidence of intracranial artery stenosis in patients with ≥20 years of smoking (trend χ2=1.043,P=0.307).Conclusions Smoking is an independent risk factor for affecting intracranial artery stenosis;the risk of disease increases with the number of smoking years.Long-term smokers (≥20 years) cannot reduce the effect on intracranial artery stenosis,even if they give up smoking.

Objective To investigate the effect of serum lipid level on carotid artery stenosis in patients with ischemic cerebrovascular disease.Methods Using a multi-center cross-sectional study,10 711 consecutive inpatients with transient ischemic attack (TIA) or ischemic stroke diagnosed clearly in 20 stroke screening and prevention project base hospitals from June 2015 to May 2016 were enrolled.According to the results of carotid ultrasonography,1 560 patients with extracranial carotid artery stenosis rate≥50% screened were enrolled in the study.They were divided into a severe stenosis group (70%-99%) and a mild-moderate stenosis group (<70%).The distribution of total cholesterol (TC),triacylglycerol (TG),low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) levels in both groups of carotid stenosis patients were analyzed,and the quantitative classification was based on the normal range of serum lipids.The distributions of serum lipid levels in different grades in patients of both groups were compared with the non-parameter test.Results The incidence of dyslipidemia in the severe stenosis group was higher than that in the mild and moderate stenosis group.There was no significant difference between the two groups (54.4%[319/586]vs.48.3%[470/974],P<0.05).Dyslipidemia was an independent risk factor for severe carotid artery stenosis (OR,1.27,95% CI 1.24-1.30,P<0.01).The TC and LDL-C levels in patients of the severe stenosis group were significantly higher than those in the mild-moderate stenosis group (TC:3.98[3.31,4.82]mmol/L vs.3.91[3.31,4.53]mmol/L,LDL-C:2.48[1.86,3.14]vs.2.30[1.79,2.80];all P<0.01).With the increase of TC and LDL-C levels,there was significant differences between the severe stenosis group and the mild-moderate stenosis group (all P<0.05),and the proportions of TC >5.80 mmol/L (7.3%[43/586]vs.0.4%[4/974]) and LDL-C>3.12 mmol/L (26.3%[154/586]vs.10.0%[97/974]) in patients of the severe stenosis group were higher than those in the mild-moderate stenosis group (26.3%[154/586]vs.10.0%[97/974]).Conclusion The high LDL-C and TC levels may increase the incidence of severe carotid artery stenosis or occlusion.