儿童1型糖尿病应用动态血糖监测系统的效能分析

目的评价动态血糖监测系统(CGMS)在儿童1型糖尿病血糖监测中的效能。方法应用CGMS监测17例1型糖尿病患儿的血糖,与指血血糖值比较,应用相关分析、血糖误差分析表格(EGA)等方法评价其效能。结果在总体、高、正常血糖水平,相匹配的CGMS血糖值与指血血糖值相关系数分别为0.96、0.92、0.94(P均<0.01);在低血糖水平,两者相关性下降(r=0.73,P<0.01)。CGMS血糖值在指血血糖值±20%和±30%范围的总体比例为88.5%、93.8%;在高、正常、低血糖水平,CGMS血糖值在指血血糖值±20%和±30%范围的比率分别为94.1%、96.5%,81.8%、90.3%,50.0%、80.0%。结论CGMS的血糖监测结果与血糖仪一致,能较准确地监测儿童1型糖尿病患儿的血糖情况,更全面地反映患儿的血糖波动特征。     

A mixture of experts network structure for modelling Doppler ultrasound blood flow signals

Mixture of experts (ME) is a modular neural network architecture for supervised learning. This paper illustrates the use of ME network structure to guide modelling Doppler ultrasound blood flow signals. Expectation-Maximization (EM) algorithm was used for training the ME so that the learning process is decoupled in a manner that fits well with the modular structure. The ophthalmic and internal carotid arterial Doppler signals were decomposed into time-frequency representations using discrete wavelet transform and statistical features were calculated to depict their distribution. The ME network structures were implemented for diagnosis of ophthalmic and internal carotid arterial disorders using the statistical features as inputs. To improve diagnostic accuracy, the outputs of expert networks were combined by a gating network simultaneously trained in order to stochastically select the expert that is performing the best at solving the problem. The ME network structure achieved accuracy rates which were higher than that of the stand-alone neural network models.     

三维适形放射治疗位置与剂量精度的验证

目的:验证三维适形放射治疗位置与剂量精度.方法:采用胶片法和电离室法,对所使用的治疗计划系统和加速器距离精度、靶中心位置精度及等中心吸收剂量进行实测验证.结果:治疗计划系统所显示图像的距离精度＜1%,靶中心位置精度＜2mm,等中心吸收剂量精度＜1%.结论:所验证的三维适形放疗位置与剂量精度符合临床要求,验证方法可行.     

Reproducibility of the interpretation of hysterosalpingography in the diagnosis of tubal pathology

The aim of the study was to estimate the inter- and intra-observerreproducibility of the interpretation of hystero-salpingography(HSG) in the diagnosis of tubal pathology, and associate reproducibilitywith diagnostic accuracy. Four observers evaluated 143 HSGstwice, on proximal tubal obstruction, distal tubal obstruction,hydrosalpinx and peritubal adhesions. Diagnostic laparoscopywith chro-mopertubation was considered to be the reference strategy.Reproducibility (inter- and intra-observer agreement) was expressedin terms of K-values. Accuracy was expressed in terms of sensitivity,specificity and likelihood ratios. K-values for reproducibilitybetween observers were almost perfect for proximal obstruction,substantial for distal obstruction and hydrosalpinx, and moderatefor adhesions. K-values for reproducibility within observerswere almost perfect for proximal obstruction and substantialfor distal obstruction, hydrosalpinx and adhesions. HSG hada high specificity for proximal obstruction, but a low sensitivity.Distal obstruction, absence of hydrosalpinx and adhesions hada poor accuracy. The likelihood ratio for the presence of hydrosalpinxwas high. In conclusion, proximal tuba! obstruction detectedon HSG changes the pre-test probability of proximal tubal obstructionfrom 16 to 50%. Proximal tubal patency detected on HSG changesthe pre-test probability of proximal tubal patency from 16 to9%. It is unlikely that a lack of reproducibility of the interpretationof proximal tuba! patency is responsible for the low sensitivity;alternative explanations are artefacts occurring while performingHSG or an imperfect reference strategy diagnostic laparoscopy.HSG is of limited use in diagnosing distal tubal obstructionand hydrosalpinx, and has no value in the detection of peritubaladhesions.     

Right ventricular volumes and ejection fraction by MR imaging and stereology: comparison with standard image analysis method

The purpose of this study was to examine the accuracy of the stereological method for estimating right ventricular parameters on cine MR images. The end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV), and ejection fraction (EF) were estimated in 19 consecutive patients with suspected or known coronary artery disease employing the stereological point counting method. Stereological measurements were performed with different grids of test points. The RV parameters were also derived by the standard method based on the manual adjustment of automatically obtained endocardial contours. The statistical difference and agreement between the two methods was found. Measurement reproducibility of both methods was determined. The counting of about 100 test points on all MR images provided EDV and ESV with a mean coefficient of error of 7.0 ± 1.3% and 7.4 ± 2.1%, respectively. The volume estimation precision was not significantly improved by counting more points (EDV: P = 0.058; ESV:P = 0.333). Stereological estimations were not significantly different from those by the standard method (EDV: P = 0.093; ESV: P = 0.072; SV: P = 0.291; EF: P = 0.300). The 95% limits of agreement between the two methods were clinically acceptable (EDV: -12.1 cm(3) , 18.9 cm(3) ; ESV: -6.4 cm(3) , 10.4 cm(3) ; SV: -10.5 cm(3) , 13.5 cm(3) ; EF: -7.5%, 6.3%). The repeatability of stereological estimations was better than that of the standard method (coefficient of variability: 3.4-5.3% versus 4.0-7.1%). The measurement time with stereolgy was less than 4 min. The stereological method may be considered as an improvement over the standard method due to its accuracy and repeatability.     

Spanish Medical Interpreters’ Management of Challenges in End of Life Discussions

ObjectiveProfessional medical interpreters facilitate patient understanding of illness, prognosis, and treatment options. Facilitating end of life discussions can be challenging. Our objective was to better understand the challenges professional medical interpreters face and how they affect the accuracy of provider-patient communication during discussions of end of life.MethodsWe conducted semi-structured interviews with professional Spanish medical interpreters. We asked about their experiences interpreting end of life discussions, including questions about values, professional and emotional challenges interpreting these conversations, and how those challenges might impact accuracy. We used a grounded theory, constant comparative method to analyze the data. Participants completed a short demographic questionnaire.ResultsSeventeen Spanish language interpreters participated. Participants described intensive attention to communication accuracy during end of life discussions, even when discussions caused emotional or professional distress. Professional strains such as rapid discussion tempo contributed to unintentional alterations in discussion content. Perceived non-empathic behaviors of providers contributed to rare, intentional alterations in discussion flow and content.ConclusionWe found that despite challenges, Spanish language interpreters focus intensively on accurate interpretation in discussions of end of life.Practice ImplicationsProvider training on how to best work with interpreters in these important conversations could support accurate and empathetic interpretation.     

Diagnostic accuracy of VIDISCA-NGS in patients with suspected central nervous system infections

ObjectivesConfirming the diagnosis in viral central nervous system (CNS) infections can be difficult with the currently available diagnostic tools. Virus discovery cDNA-amplified fragment length polymorphism next-generation sequencing (VIDISCA-NGS) is a promising viral metagenomic technique that enables the detection of all viruses in a single assay. We performed a retrospective study on the diagnostic accuracy of VIDISCA-NGS in cerebrospinal fluid (CSF) of individuals with suspected CNS infections.MethodsConsecutive adult patients presenting to the Emergency Department or inpatients, who underwent a lumbar puncture for the suspicion of a CNS infection, were included if they were diagnosed with a viral CNS infection, or if a viral CNS infection was initially suspected but eventually a different diagnosis was made. A quantitative PCR panel of the most common causative viruses was performed on CSF of these patients as reference standard and compared with the results of VIDISCA-NGS, the index test.ResultsWe included 38 individuals with viral CNS infections and 35 presenting with suspected CNS infection for whom an alternative aetiology was finally established. Overall sensitivity and specificity were 52% (95% CI 31%–73%) and 100% (95% CI 91%–100%), respectively. One enterovirus, detected by VIDISCA-NGS, was only identified by quantitative PCR upon retesting. Additional viruses identified by VIDISCA-NGS consisted of GB virus C, human papillomavirus, human mastadenovirus C, Merkel cell polyoma virus and anelloviruses.ConclusionIn patients for whom routine diagnostics do not yield a causative pathogen, VIDISCA-NGS can be of additional value as it can detect a broader range of viruses, but it does not perform well enough to replace quantitativePCR.     

Novel point-of-care biomarker combination tests to differentiate acute bacterial from viral respiratory tract infections to guide antibiotic prescribing: a systematic review

BackgroundAcute respiratory tract infections (RTIs) are the most common reason to seek medical care, with many patients receiving inappropriate antibiotics. Novel testing approaches to identify aetiology at the point-of-care are required to accurately guide antibiotic treatment.ObjectiveTo assess the diagnostic accuracy of biomarker combinations to rapidly differentiate between acute bacterial or viral RTI aetiology.Data sourcesMEDLINE, Embase and Web of Science databases were searched to February 2021.Study eligibility criteriaDiagnostic accuracy studies comparing accuracy of point-of-care and rapid diagnostic tests in primary or secondary care, consisting of biomarker combinations, to identify bacterial or viral aetiology of RTI.MethodsRisk of bias was assessed using the QUADAS-2 tool. Sensitivity and specificity of tests reported by more than one study were meta-analysed using a random effects model.ResultsTwenty observational studies (3514 patients) were identified. Eighteen were judged at high risk of bias. For bacterial aetiologies, sensitivity ranged from 61% to 100% and specificity from 18% to 96%. For viral aetiologies, sensitivity ranged from 59% to 97% and specificity from 74% to 100%. Studies evaluating two commercial tests were meta-analysed. For ImmunoXpert, the summary sensitivity and specificity were 85% (95% CI 75%–91%, k = 4) and 86% (95% CI 73%–93%, k = 4) for bacterial infections, and 90% (95% CI 79%–96%, k = 3) and 92% (95% CI 83%–96%, k = 3) for viral infections, respectively. FebriDx had pooled sensitivity and specificity of 84% (95% CI 75%–90%, k = 4) and 93% (95% CI 90%–95%, k = 4) for bacterial infections, and 87% (95% CI 72%–95%; k = 4) and 82% (95% CI 66%–86%, k = 4) for viral infections, respectively.ConclusionCombinations of biomarkers show potential clinical utility in discriminating the aetiology of RTIs. However, the limitations in the evidence base, due to a high proportion of studies with high risk of bias, preclude firm conclusions. Future research should be in primary care and evaluate patient outcomes and cost-effectiveness with experimental study designs.Clinical trialPROSPERO registration number: CRD42020178973.     

鼻咽癌放疗中红外定位系统与锥形束CT的摆位精度比较

目的:量化研究鼻咽癌放射治疗过程中红外定位系统OPS与锥形束CT(CBCT)摆位精度的差异。方法:随机选取南通市肿瘤医院2018年4月~11月收治的鼻咽癌患者21例,使用头颈肩热塑膜固定体位,CT扫描前,在热塑膜上粘贴OPS专用定位球6个。首次治疗时使用千伏级CBCT进行位置验证,并移床校正,记录CBCT移床值和移床后的OPS监测偏差值。选择CBCT肿瘤中心摆位值作为理想放疗摆位参考,对室内激光定位系统的肿瘤中心摆位值和OPS肿瘤中心摆位值进行比较和分析。当摆位误差在2.0 mm内,则被认定与CBCT摆位临床一致。结果:与室内激光定位系统摆位相比,OPS大大提高了鼻咽癌放疗摆位的精度。OPS与CBCT在鼻咽癌放疗摆位一致性结果为:患者左右方向(用x轴表示)95.2%、腹背方向(用y轴表示)71.4%、头脚方向(用z轴表示)100.0%。腹背偏差较大主要是因为放射治疗计划系统选择颈椎骨作为参考点,此时选择CBCT摆位将无法消除颈椎骨弯曲产生的偏差。结论:OPS实现了在鼻咽癌放疗中实时、准确和快速的患者摆位,代替室内激光定位系统大大提高了鼻咽癌放疗摆位精度。在鼻咽癌放疗摆位精度方面,OPS和CBCT表现出较高的一致性,而且在每次放疗中均可使用。