MRS and diffusion tensor image in mild traumatic brain injuries

Objective:To analyze characters of magnetic resonance spectroscopy(MRS) and diffusion tensor imaging(DTI) in the diagnosis of mild trauma brain injuries(MTBI) in frontal lobe and to compare with conventional magnetic resonance imaging(MRI).Methods:A total of 21 patients were selected,who all aged 12-51 years old and had injury within 24 hours.Computer tomography (CT) and the Glasgow Coma Scale were used to evaluate the degree of injury.All patients were diagnosed as MTBI,and 19 had conventional MRI,MRS and DTI.The major parameters of MRS were Probe-P sequence,TE= 144 or 35 ms,and both single voxel spectrum and chemical shift imging were included.The major parameters of DTI were diffusion directions =15,b value = 1000 s/mm^2. Frational anisotropic(FA) map and average ADC map were obtained to evaluate DTI result. Positive deletion ratio was observed and the imaging changes were compared between injured side and normal side.Results:All 21 patients had CT scan and Glasgow scale.A total of 19 patients had conventional MRI.DTI and MRS.Results of CT and conventional MRI showed no significant abnormality in lobe,and Glasgow scale showed mild type.MRS result showed significant decrease in N-acetyl aspartate(NAA) and NAA/creatine(Cr) in 13 cases(68.4%) (P【0.001),and increase in lactic acid(Lac) in 7 cases(36.8%).FA mapping of the frontal lobe displayed significant changes in 7 cases(36.8%),with 5 out of the 7 cases having increase in FA value.And there was no significant difference in average ADC.Conclusions:MRS and DTI might be more sensible than other methods,such as CT and conventional MRI in diagnosis of MTBI.The particular changes were reduced NAA and increased Lac for MRS.and increased FA values for DTI.

Prevalence and Spectrum of Complex Congenital Heart Disease in the Neonatal Intensive Care Unit at High Altitude in China

Background:Previous studies from high altitudes have reported significantly higher prevalence of congenital heart disease(CHD),consisting almost solely of simple CHD.Little is known about the occurrence of complex CHD.Neonates with complex CHD are likely admitted to NICU.We examined the prevalence and spectrum of complex CHD in NICU in order to depict a truer picture of CHD at high altitude.Methods:We reviewed charts of 4,214 neonates admitted to NICU in Qinghai province(average altitude 3,000 m).Echocardiography was performed in 1,943 babies when CHD was suspected based on clinical examinations.Results:CHD was diagnosed in 1,093(56.3%of echoed babies).Mild CHD in 96.8%(1058 babies).Moderate CHD in 0.8%(9)included 1(0.1%)large secundum atrial septal defect,3(0.3%)moderate pulmonary stenosis,2(0.2%)aortic stenosis and 3(0.3%)partial anomalous pulmonary venous connection.Severe CHD in 2.4%(26)included 6(0.5%)complete atrioventricular septal defect,5(0.5%)complete transposition of the great arteries,5(0.5%)hypoplastic right heart,3(0.3%)hypoplastic left heart,3(0.3%)double outlet right ventricle,3(0.3%)tetralogy of Fallot,2(0.2%)truncus arteriosus,2(0.2%)total anomalous pulmonary venous connection,2(0.2%)severe aortic stenosis,2(0.2%)interrupted aortic arch and 2(0.2%)severe pulmonary stenosis and 1(0.1%)single-ventricle abnormality.At two-years follow-up in 737(67.4%)patients,18(90%)with severe CHD and 38(5.3%)with mild and moderate CHD died,and 15 underwent cardiac surgery with 1 early death.Conclusions:At high altitude,a wide spectrum of CHD exists,with many heretofore unreported complex CHD.There is urgent need for routine echocardiography and early interventions in newborns particularly in NICU.

Numerical Investigation on Flow and Heat Transfer Performance of Supercritical Carbon Dioxide Based on Variable Turbulent Prandtlnumber Model

Flow and heat transfer characteristic of supercritical carbon dioxide(SCO_(2))are numerically investigated in the horizontal and vertical tubes.TWL turbulent Prandtl number model could well describe the behavior of SCO_(2) affected by the buoyancy.Under the cooling condition,the heat transfer performance of SCO_(2) along the upward direction is best and that along the downward direction is worst when bulk fluid temperatures are below the pseudocritical temperature.Reducing the ratio of heat flux to mass flux could decrease the difference of convective heat transfer coefficient in three flow directions.Under the heating condition,heat transfer deterioration only occurs in vertical upward and horizontal flow directions.Heat transfer deterioration of SCO_(2) could be delayed by increasing the mass flux and the deterioration degree is weakened in the second half of tube along the vertical upward flow direction.Compared with the straight tube,the corrugated tube shows better comprehensive thermal performance.