Comparing the In Vivo Diagnostic Accuracy of Digital Periapical Radiography with Cone-beam Computed Tomography for the Detection of Vertical Root Fracture

Introduction

The purpose of this study was to determine whether there is a difference in the in vivo diagnostic accuracy of digital radiography (DR) and cone-beam computed tomography (CBCT) imaging in the detection of vertical root fracture (VRF). The presence/absence of VRF was confirmed by visual inspection of the extracted root surface and was the reference standard against which both imaging modalities were compared.

Methods

Twenty-one unsalvageable teeth from 20 patients that had been radiographed and scanned with CBCT imaging were included in the study. The teeth were atraumatically extracted and visually inspected under a microscope to confirm the presence/absence of fracture. The widest point of each fracture was recorded using an optical coherence tomography scanner in order to quantify the size of fractures. Images were viewed under standardized conditions by 13 examiners and repeated 2 weeks later to assess their consistency.

Results

DR and CBCT imaging showed similarly poor sensitivity of 0.16 and 0.27, respectively. Both imaging modalities had similarly high specificity of 0.92 and 0.83, respectively. There was no statistical difference between the diagnostic accuracy of either imaging modality. Fracture width did not affect the detection rate of either imaging modality. Receiver operating characteristic analysis revealed mean A_z values of 0.535 and 0.552 for DR and CBCT imaging, respectively.

Conclusions

Both DR and CBCT imaging have significant limitations when detecting vertical root fractures.     

Evaluation of two oxygen analyzers by computerized data acquisition and processing

Monitoring of inspired oxygen concentration during anesthesia with nitrous oxide is becoming accepted as essential. This type of monitoring demands accurate monitors that respond rapidly. We evaluated two such devices for their response patterns to rapid changes in oxygen concentration, a galvanic or “fuel cell” unit and a polarographic device. Data were stored after analog-to-digital conversion. The response patterns to stepwise changes in nitrous oxide and oxygen mixtures were recorded at flow rates ranging from 2 to 10 L/min. Both units responded accurately to all changes in the absolute oxygen concentration; the polarographic unit was, on average, twice as fast. Responsiveness to nitrous oxide was low (<0.4% at 100% nitrous oxide), and the stability of the signals was good. The 90% response time (T₉₀) was consistent for any stepwise increase or decrease in oxygen concentration between 0, 21, 33, 50, and 100%. After a step change from 0 to 100% oxygen at a gas flow rate of 10 L/min, the T₉₀ was 5.8 seconds in the polarographic device and 11.4 seconds in the galvanic device (p<0.01). After a decrease from 100 to 0% oxygen, the T₉₀ was 0.6 second longer in both monitors. Comparing flow rates of 2 L/min with 10 L/min, the T₉₀ was delayed by 1.1 and 2.3 seconds for an increase, and by 1.4 and 2.9 seconds for a decrease in oxygen concentration. Experimental data suggest that both sensors respond adequately during routine clinical use. The faster response of the polarographic device is probably of limited clinical relevance, but it may aid in calibration.     

原发性小肠肿瘤142例诊治分析

目的 探讨小肠肿瘤的临床病理特点，提高对本病的诊治水平。方法 对1968年1月至2001年9月本院收治的142例小肠肿瘤的临床资料进行回顾性分析。结果 142例小肠肿瘤中，良性43例，恶性99例。良性以平滑肌瘤为多，占53.5％（23／43）；恶性以腺癌和淋巴瘤为多，分别占45.4%（45／99）和34．3％（34／99）。腹痛、腹部肿块、肠梗阻及便血是小肠肿瘤的四大常见临床表现。本组术前确诊37例，仅占26.1%。十二指肠镜、CT和B超对十二指肠肿瘤有较高的诊断率、小肠造影、DSA对诊断空回肠肿瘤有一定的作用。结论 小肠肿瘤临床表现无特异性，术前诊断较困难，临床上要提高警惕。     

Human inhalable antibody fragments neutralizing SARS-CoV-2 variants for COVID-19 therapy

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尺骨冠状突骨折合并肘关节后脱位有限元模型的建立与分析

目的：建立尺骨冠状突骨折合并肘关节后脱位的有限元模型,并对肘关节后脱位在关节稳定性方面的影响进行数字化研究。方法：建立正常肘关节-前臂（IEJF）有限元模型与尺骨冠状突骨折肘关节-前臂（FUCF）有限元模型。采用压缩、屈曲两组生理荷载（每组3种幅值）,进行计算、验证和应力分析。结果：建立了结构完整的IEJF与FUCF有限元模型,并对模型进行验证,情况与临床实际符合。计算得出FUCF有限元模型较IEJF有限元模型桡骨头出现了严重的应力集中现象,不同压缩荷载作用下的肘关节纵向压缩位移与不同屈曲力矩导致的屈曲角都有所增加。结论：尺骨冠状突骨折及肘关节后脱位对肘关节-前臂纵向不稳有一定程度的影响。本研究所构建的肘关节-前臂有限元模型对尺骨冠状突骨折合并肘关节后脱位的临床稳定性评估研究及手术治疗方案的制定具有一定的参考价值。     

Monitoring Treatment Response and Metastatic Relapse in Advanced Bladder Cancer by Liquid Biopsy Analysis

Of the patients undergoing radical cystectomy, 20–80% experience relapse. Minimally invasive methods for early detection of metastatic relapse after cystectomy and for monitoring ongoing therapy are urgently needed to improve individualised follow-up and treatment. Therefore, we evaluated the use of circulating tumour DNA (ctDNA) in plasma and urine to detect metastatic relapse after cystectomy and measure treatment efficacy. We exome sequenced tumour and germline DNA from patients with muscle-invasive bladder cancer and monitored ctDNA in 370 liquid biopsies throughout the disease courses by 84 personalised digital droplet polymerase chain reaction assays targeting 61 genes. Patients were prospectively recruited between 2013 and 2017. Patients with metastatic relapse had significantly higher ctDNA levels compared with disease-free patients (p < 0.001). The median positive lead time between ctDNA detection in plasma and diagnosis of relapse was 101 d after cystectomy (range 0–932 d). Early detection of metastatic relapse and treatment response using liquid biopsies represents a novel, highly sensitive tool for monitoring patients, supporting clinicians, and guiding treatment decisions.