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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 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 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 investigate MRI signal features and MRI appearances of patients with advanced stage in polyacrylamide hydrophilic gel injection for facial plasty.Methods In this study,MRI of 11 cases with 23 polyacrylamide hydrophilic gel injection of facial plasty for 6 to 10 years were retrospectively reviewed.All images were acquired with GE 3.0T MR imaging unit.MR sequences,including FSE T1WI,FSE FS T2WI,and STIR were applied with 8-channel brain coil.MRIs sliced through the maxillofacial region in the transverse,coronal and sagittal planes.Results In 11 cases of 23 polyacrylamide hydrophilic gel injection,there were different degrees of capsule rupture and induration in 6 polyacrylamide hydrophilic gel injection,and the images showed sporadic callosities such as subcutaneous nodules and nodules in glands or muscles ; hydrogel migration in 8 polyacrylamide hydrophilic gel injection.Secondary deformity occured in 80 ％ cases,in which the most cases were induced by hydrogel migration.Conclusions Magnetic resonance imaging can make clear of the type of rupture and the distribution leakage of polyacrylamide hydrophilic gel for facial plasty and it is an ideal approach for advanced patients with polyacrylamide hydrophilic gel injection for follow-up.