Résumé
@#Objective To explore the clinical value of 3D artistic spin labeling technology in evaluating early perfusion changes of leukaraiosis.Methods Ninety patients and 30 healthy volunteers with different degrees of LA who were examined by magnetic resonance imaging were collected from January 2018 to April 2020.According to the Fazekas scale,they were divided into LA0,LA1,LA2 and LA3 group,30 cases were included in each group.CBF values of cortical watershed and subcortical watershed were measured according to cerebral blood flow pseudocolor image,and cerebral perfusion differences in anterior,posterior,radial crown and semicircular center of cortical watershed in different LA grades were evaluated,and the characteristics of early hemodynamic changes of LA were analyzed.Results The CBF values of LA2,LA3 were significantly lower than that of LA0.There was no significant difference between LA1 and LA0 (P>0.05),however,the CBF in subcortical watershed was slightly lower than LA0 (P<0.05).Conclusion 3D ASL perfusion imaging technology can be used to quantify the CBF in the watershed area,and can be used to monitor the state of cerebral perfusion in LA patients.The CBF response in the subcortical watershed area is more sensitive,which can be used to evaluate the early cerebral hemodynamic changes in LA.
Résumé
BACKGROUND: Currently, acid etching and bonding technology have been widely used in clinical stomatology. Data have indicated that the main content of inorganic elements (calcium and phosphorus) has a certain difference between the dental enamel and dentin of the young and adult permanent teeth. OBJECTIVE:To measure the content of main inorganic elements, calcium and phosphorus, in the dental enamel and dentin from young and adult permanent teeth with spectrophotometry and ethylene diamine tetraacetie acid titration method. METHODS:Each 20 adult and young permanent teethin vitrowere selected. Plaster stone and water was mixed; when it was nearly dried, the teeth were verticaly cast in the mixture and the tooth surface was exposed. The models were cut into the slices using syj-200 precision cutting machine, and then the slices were put into nitric acid and dissolved through heater to prepare standard solution. At last, the concentrations of calcium and phosphorus in the hard tissue of both young and adult permanent teeth were measured with spectrophotometric method and titration method. RESULTS AND CONCLUSION:The content of calcium and phosphorus and calcium/phosphorus ratio in the hard tissue of young permanent teeth were less than those of adult permanent teeth (P < 0.05), reflecting that the organic matter content was more than that in adult permanent teeth, but their mineralized degree was inferior to that of adult permanent teeth (P < 0.05). These findings indicate that the young permanent teeth are more acid proof than the adult permanent teeth; therefore, the acid etching time can be properly prolonged for young permanent teeth in clinical treatment, in order to achieve better effects.