彩色多普勒超声帧差伪像的成因与特征探讨

本文目的在于探讨超声帧差伪像的形成原因与声像图特征。通过分析医用超声诊断仪器所采用的设计模型与人体组织声学特性之间存在的矛盾、探头振元数与物理通道数之间的匹配关系、2D图像与彩色多普勒图像在显示屏上的“实时”复合方式,揭示出在图像复合显示过程中,因帧频不同而导致的人体解剖结构与血流信号在时间、空间上“错位”而导致的伪像,阐明它具有的必然性、复合性、隐蔽性、低关注度特点,为仪器设计开发和超声医生在工作中及时识别帧差伪像,减少误诊,提供思路。     

Single whole‐leg compression ultrasound for exclusion of deep vein thrombosis in symptomatic ambulatory patients: a prospective observational cohort study

International guidance has recently recommended serial proximal compression ultrasound (CUS) as first line imaging for suspected deep vein thrombosis (DVT). Single whole‐leg CUS is a routine alternative diagnostic strategy that can reduce repeated attendances and identify alternative pathology. We conducted a prospective observational cohort study. Consecutive ambulatory, adult patients with suspected DVT and negative or inconclusive whole‐leg CUS had anticoagulation withheld and were followed for 3 months. The primary outcome was a predefined clinically relevant adverse event rate. Secondary outcomes included technical failure, alternative diagnoses and all cause mortality. 212 patients agreed to participate and completed follow up. One patient was subsequently diagnosed with an isolated distal DVT. The adverse event rate was thus 1/212, 0·47% (95% confidence interval [CI] 0·08–2·62). Technical imaging failure occurred in 11·3% of cases (95% CI 7·7–16·3). Several potential predictors of an inconclusive result were identified on multivariate analysis. 150 (70·8%) patients were provided with a documented alternative diagnosis. Patients who have anticoagulation withheld following a negative or inconclusive whole‐leg CUS for suspected DVT have a low rate of adverse events. Technical failure remains an issue: several factors were significantly associated with inconclusive results and may warrant an alternative diagnostic approach.     

Ultrasound Examination to Visualize and Trace Sinus Tracts of Endodontic Origin

IntroductionThe detection of a tooth with a sinus tract (ST) of endodontic origin and its pathway are conventionally assessed with a periapical radiograph and a gutta-percha cone introduced into its stoma. The aim of this study was to evaluate the possibility to detect STs and trace their route using ultrasound real-time examination.MethodsTwo calibrated examiners performed echography on 10 patients who had a lesion of apical periodontitis (AP) and ST and 10 patients in the control group with AP without an ST recruited in 2 endodontic practices. They also traced the pattern of the STs with a computer program. The images were then submitted to 2 calibrated and blinded observers who were asked to describe the presence of AP and ST and to trace it with the same program. The data obtained were compared with the clinical and radiographic diagnosis of ST. For sensitivity, specificity, accuracy, and positive and negative predictive values, the receiver operating characteristic curve and Fisher exact test were used (P < .05).ResultsInterobserver agreement was high as was the diagnostic accuracy of the ultrasound examination of STs (mean value = 97.5%), and the Fisher exact test showed statistical significance (P < .05). High sensitivity and a negative predictive value and 100% specificity and a positive predictive value were also obtained. The application of the 3-dimensional mode further enabled the reconstructions of the more complex paths, and the implementation with color power Doppler disclosed the vascularity surrounding the STs.ConclusionsThe ultrasound examination is a technique feasible to describe and trace the STs of endodontic origin.     

血液透析患者脑血流动力学变化与认知功能损伤相关性临床研究

目的探讨维持性血液透析(MHD)患者脑血流动力学变化与认知功能损伤的关系。方法对2017年5月至6月在北京世纪坛医院94例MHD患者,根据蒙特利尔认知评估量表(MoCA)评估分为认知功能损伤(CI)组与认知功能正常(NC)组。采用经颅多普勒超声(TCD)进行脑血流动力学检查。比较两组患者之间相关指标,采用二分类Logistic回归方法分析CI与TCD指标的关系。结果 94例患者中,CI组59例,NC组35例,CI患病率为62.8%。CI组年龄、女性患者比例、透析龄及心脏病患病比例均高于NC组,受教育程度低于NC组(P<0.05)。CI组大脑中动脉(MCA)及大脑前动脉(ACA)的平均血流速(Vm)均低于NC组,MCA及ACA的搏动指数(PI)均高于NC组(P<0.05)。Logistic回归结果显示,年龄、心脏病史、MCA-Vm及MCA-PI是MHD患者CI发生的相关危险因素(P<0.05)。结论MHD患者颅内动脉平均血流速度降低,其中MCA-Vm越低,MCA-PI越高,患者发生认知功能损伤的风险越大。     

高血容量血液稀释对老年患者围术期血流动力学的影响

目的:观察高血容量血液稀释(hypervolemic hemodilution,HHD)对老年患者围术期血流动力学的影响。方法:选取20名无心脏病史的麻醉手术患者;10名患者65周岁,10名55周岁。所有入试患者在术前接受相同的HHD处理(60 g/L羟乙基淀粉静脉输注,15 ml/kg)。在血液稀释后不同时间使用经食管多普勒超声监测(transesophageal Doppler monitoring,TDM)患者的血流动力学变化,同时监测患者血细胞比容(Hct)、血红蛋白、血气及心电变化。结果:所有患者手术期间均未发生任何并发症。两组患者间的一般资料、生化检查数据、Hct、血气等均无统计学差异。HHD后对照组(55周岁)的心排出量(cardiac output,CO)升高,老年组(65周岁)降低。对照组的心率(heart rate,HR)下降和心搏指数(stroke index,SI)升高(P0.05),而老年组HR无明显改变,SI轻微下降。血液稀释后对照组患者的外周血管阻力值有明显下降(P0.05),而老年患者出现了升高的趋势。结论:无心脏病史的老年患者并不能很好耐受术前急性高容量血液稀释。HHD可以导致由SI下降所致的CO下降。