Effectiveness of the 10-valent pneumococcal conjugate vaccine against radiographic pneumonia among children in rural Bangladesh: A case-control study

BackgroundPneumococcal conjugate vaccine (PCV) effectiveness against radiographic pneumonia in South Asia is unknown. Bangladesh introduced PCV10 in 2015 using a three dose primary series (3 + 0). We sought to measure PCV10 effectiveness for two or more vaccine doses on radiographic pneumonia among vaccine-eligible children in rural Bangladesh.MethodsWe conducted a matched case-control study over two years from 2015 to 2017 using clinic and community controls in three subdistricts of Sylhet, Bangladesh. Cases were vaccine eligible 3–35 month olds at Upazila Health Complex outpatient clinics with World Health Organization-defined radiographic primary endpoint pneumonia (radiographic pneumonia). Clinic controls were matched to cases within a one week time window by age, sex, and clinic and had an illness unlikely to be Streptococcus pneumoniae; community controls were healthy and similarly matched within a one week time window by age and sex, and distance from the clinic. We estimated adjusted vaccine effectiveness (aVE) using conditional logistic regression.ResultsWe matched 1262 cases with 2707 clinic and 2461 community controls. Overall, aVE using clinic controls was 21.4% (95% confidence interval, −0.2%, 38.4%) for ≥2 PCV10 doses and among 3–11 month olds was 47.3% (10.5%, 69.0%) for three doses. aVE increased with higher numbers of doses in clinic control sets (p = 0.007). In contrast, aVE using community controls was 7.6% (95% confidence interval, −22.2%, 30.0%) for ≥2 doses. We found vaccine introduction in the study area faster and less variable than expected with 75% coverage on average, which reduced power. Information bias may also have affected community controls.ConclusionsClinic control analyses show PCV10 prevented radiographic pneumonia in Bangladesh, especially among younger children receiving three doses. While both analyses were underpowered, community control enrollment – compared to clinic controls – was more difficult in a complex, pluralistic healthcare system. Future studies in comparable settings may consider alternative study designs.     

The effect of different statistical approaches on image quality data obtained from radiological examinations

IntroductionSelection of optimal image acquisition protocols in medical imaging remains a grey area, the superimposed use of the Likert scale in radiological image quality evaluations creates an additional challenge for the statistical analysis of image quality data.Using a simulation study, we have trialled a novel approach to analysing radiological image quality Likert scale data.MethodsA simulation study was undertaken where simulated datasets were generated based on the distribution of Likert scale values according to varying image acquisition protocols from a real dataset. Simulated Likert scale values were pooled in four different ways; the mean, median, mode and the summation of patient Likert scale values of which the total was assigned a categorical Likert scale value. Estimates of bias, MAPE and RMSPE were then calculated for all four pooling approaches to determine which method most accurately represented an expert's opinion.ResultsWhen compared to an expert's opinion, the method of summation and categorisation of Likert scale values was most accurate 49 times out of the 114 (43.0%) tests. The mean 28 times out of 114 (24.6%), the median 23 times out of 114 (20.2%) and the mode 17 times out of 114 (14.9%).ConclusionWe conclude that our method of summation and categorisation of Likert scale values is most often the best representation of the simulated data compared to the expert's opinion.Implications for practiceThere is scope to reproduce this simulation study with multiple observers to reflect clinical reality more accurately with the dynamic nature of multiple observers. This also prompts future investigation into other anatomical areas, to see if the same methods produce similar results.     

Analysis of radiation exposure data from common radiological procedures in Dutch hospitals

IntroductionIn the Netherlands, Diagnostic Reference Levels (DRLs) have not been based on a national survey as proposed by ICRP. Instead, local exposure data, expert judgment and the international scientific literature were used as sources. This study investigated whether the current DRLs are reasonable for Dutch radiological practice.MethodsA national project was set up, in which radiography students carried out dose measurements in hospitals supervised by medical physicists. The project ran from 2014 to 2017 and dose values were analysed for a trend over time. In the absence of such a trend, the joint yearly data sets were considered a single data set and were analysed together. In this way the national project mimicked a national survey.ResultsFor six out of eleven radiological procedures enough data was collected for further analysis. In the first step of the analysis no trend was found over time for any of these procedures. In the second step the joint analysis lead to suggestions for five new DRL values that are far below the current ones. The new DRLs are based on the 75 percentile values of the distributions of all dose data per procedure.ConclusionThe results show that the current DRLs are too high for five of the six procedures that have been analysed. For the other five procedures more data needs to be collected. Moreover, the mean weights of the patients are higher than expected. This introduces bias when these are not recorded and the mean weight is assumed to be 77 kg.Implications for practiceThe current checking of doses for compliance with the DRLs needs to be changed. Both the procedure (regarding weights) and the values of the DRLs should be updated.     

Concerns for medical radiation programs in Australian universities

The Australian higher education system is in a state of great change. The Federal education minister, Dr Brendan Nelson, has indicated that he intends to continue introducing far-reaching reforms that will impact significantly on how universities conduct teaching and research. The future allocation of government funding for university programs, including those in medical radiation, will have a significant effect on how those programs are delivered and could even determine whether programs remain viable. There will be a financial imperative for academic departments to strengthen research activity and to obtain funding from non-government sources, such as full-fee paying students, in order to generate enough income to cover program delivery. Medical radiation education in Australia is also facing many other challenges. Some of these are longstanding, such as the high cost of medical radiation program delivery, poor levels of research activity and difficulty in recruiting and retaining academic staff. Other problems have arisen recently, such as increased competition for students and a critical shortage of available training placements in clinical practice. The aim of this paper is to raise and explore these issues from a university perspective.     

肝动脉化疗栓塞术治疗中晚期肝癌的疗效评价

目的评价应用碘化油及四氧化三铁（Fe3O4）微球栓塞治疗原发性巨块型肝癌的临床疗效。方法回顾分析行超选择插管栓塞原发性巨块型肝癌246例,分两组,以碘化油6-27 ml＋Fe3O4250μm,丝裂霉素（10 mg）,5-Fu 250 mg混悬液栓塞,主干应用明胶海绵栓塞126例,选择同期常规剂量碘化油及明胶海绵治疗巨块型肝病120例作为对照组,碘化油用量6-27 ml,分析两组术前后病灶大小变化,近期有效率及生存率。结果碘化油及Fe3O4组近期有效率明显高于碘化油组,碘化油及Fe3O4组1、2、3年生存率分别为89.3%、42.7%、31.2%,而碘化油组分别为53.8%、14.9%、12.6%。结论碘化油及Fe3O4微球治疗巨块型肝癌较碘化油栓塞组疗效有明显提高,可视为治疗巨块型中晚期肝病的有效方法。     

计算机X线摄影图像的静止滤线栅伪影分析

目的通过分析计算机X线摄影（CR）系统的采样频率和栅密度频率，提出尽可能有效避免滤线栅伪影出现的抑制方法。方法实际测试不同栅密度的滤线栅与不同规格的成像板（IP）匹配使用，得到不同效果的图像；模拟2种信号频率（即2种栅密度的滤线栅），采用3种采样频率[6、8、10图像空间分辨率（pixels／mm）]，得到不同的模拟图像效果。结果通过对比分析模拟图和实际图像，发现在采样频率正好等于信号频率的2倍时，可以得到正确的信号频率，图像清晰，无混淆现象。栅密度〈4LP／mm时，可较好地与14in×14in、10in×12in（1in=2．54cm）IP匹配使用。结论CR系统与普通IP匹配使用合适的采样频率和栅密度频率，可以有效避免滤线栅伪影出现。     

气管与主支气管肿瘤的影像诊断（附32例报告）

作者对３２例经病理证实的气管与主支气管良、恶性肿瘤的影像学表现进行分析，归纳为３型：腔内型、壁增厚型和腔内外型。后２种类型提示恶性，而无蒂的腔内型表现者不能鉴别良，恶性。作者还评价了常规体层、ＣＴ及ＭＲＩ诊断气管与主支气管肿瘤的优、缺点，讨论了影像诊断的作用。