Comparison of digital systems and conventional dental film for the detection of approximal enamel caries

Objectives

The aims of this study were (1) to compare the accuracy of the detection of approximal enamel caries lesions using three intraoral storage phosphor plate digital systems and one conventional film-based radiographic system; and (2) to determine whether there is a correlation between the histological and radiographic measurements of enamel caries.

Methods

160 approximal surfaces were radiographed under standardized conditions using three storage phosphor stimulable systems (DenOptix and Digora FMX with white and blue plates), and one film system (Insight film). 17 observers scored the images for the presence and depth of caries using a 4-point scale. The presence of caries was validated histologically (gold standard). Two-way analysis of variance was used to test the differences in sensitivity, specificity and overall accuracy (TP + TN). The data from the radiographic and histological measurements were statistically analysed by Spearman’s rank correlation coefficient.

Results

Two-way analysis of variance and the post hoc t-test demonstrated that Digora (white plate) had higher specificity and overall accuracy values than DenOptix (P = 0.021); there was no statistically significant difference among the other imaging modalities (P > 0.05). There was no significant correlation between the histological depth measurements and the radiographic measurements from Digora (blue plate) (P = 0.43), Digora (white plate) (P = 0.15), DenOptix (P = 0.17) and Insight film (P = 0.06).

Conclusions

The results suggest that (1) the performance of the three storage phosphor image plate systems was similar to that of the Insight film for detection of approximal enamel caries, and (2) the increase in histological depth of enamel caries was not significantly correlated with radiographic measurements.     

An analysis of eccentric photo refraction

The optics of eccentric photo refraction are analysed. The variation of photo refractive lunula area with refractive error, pupil size, flash eccentricity and camera aperture were calculated using a model eye. Measurements from photographs of paraxial (eccentric) photo refraction of model eyes show that a good agreement exists between theory and experiment over a range of refractive errors from — 10 D to +10 D. Calculations were also made for a standard reduced eye. The optimal set-up for measuring refractive error accurately over a wide range of refractive states is discussed, as are the problems which arise from non-central fixation.     

Pulmonary histiocytosis X: comparison of radiographic and CT findings

The authors retrospectively evaluated radiographs, computed tomographic (CT) scans, and results of pulmonary function tests (when available) for 17 patients with biopsy-proved pulmonary histiocytosis X. In 11 patients, high-resolution CT was used. In 12 patients, CT demonstrated cystic air spaces, usually less than 10 mm in diameter. In three of these 12, cysts were the only abnormality, but in six others, nodules (usually less than 5 mm in diameter) were also present. Two patients had only nodules and one, only emphysema. CT showed that many lesions that appeared reticular on plain radiographs were actually cysts. CT showed no central or peripheral concentration of lesions, but it did reveal that many small nodules were distributed in the centers of secondary lobules around small airways. CT findings correlated better with the diffusing capacity (rho = -0.71) than did the plain radiographic findings (rho = -0.57). Thus, CT was better than radiography at showing the morphology and distribution of lung abnormalities.     

不同孔径纳米羟基磷灰石人工骨修复兔桡骨缺损效果比较

目的:纳米级的羟基磷灰石材料与人体内组织成分更为相似,具有更佳的生物性能。评价不同孔径的多孔纳米羟基磷灰石人工骨的骨缺损修复能力,从而筛选出适合的孔径以达到骨传导功能与生物力学性能的良好统一。方法:实验于2005-10/2006-10在深圳市第二人民医院中心实验室完成。①实验材料:纳米羟基磷灰石人工骨以硝酸钙和磷酸二氢铵为原料,采用溶胶-絮凝法制备粉体,运用压力成型、木模成型和浸渍成型分别制得孔隙分布均匀的孔径分别为50～150μm、100～250μm和300～500μm的多孔纳米羟基磷灰石人工骨。②实验动物:雄性新西兰大白兔60只随机分为植入50～150μm孔径材料组、植入100～250μm孔径材料组、植入300～500μm孔径材料组、空白对照组,每组15只。实验过程中对动物处置符合动物伦理学要求。③实验方法:制备双侧桡骨骨缺损动物模型,然后用3种不同孔径的纳米羟基磷灰石人工骨材料植入骨缺损处进行修复,空白对照组不植入任何材料。④实验评估:术后4,8和12周分别行大体标本观察、X射线片观察、扫描电镜观察及生物力学测试,比较各组材料修复骨缺损的能力。结果:实验动物均进入结果分析。①X射线片检查结果:术后4周、8周、12周,植入100～250μm孔径材料组X射线评分高于植入50～150μm,300～500μm孔径材料组,差异有显著性意义(P<0.05)。②生物力学检测结果:术后4周、8周、12周,植入100～250μm孔径材料组生物力学强度高于植入50～150μm,300～500μm孔径材料组,差异有显著性意义(P<0.05)。③扫描电镜观察结果:植入100～250μm孔径材料组成骨效果明显优于植入50～150μm,300～500μm孔径材料组和空白对照组。结论:纳米羟基磷灰石人工骨具有良好的成骨能力,但其骨修复能力受孔径因素的影响,孔径100～250μm的纳米羟基磷灰石人工骨材料成骨能力较好。     

Inflammatory bowel disease and the X chromosome

A review of documented cases demonstrates a significant association of Turner's syndrome with Crohn's disease and ulcerative colitis; this association relates particularly to genetic constitutions comprising an abnormal rather than an absent X chromosome. The karyotype 46XiXq, in pure or mosaic form, appears to be a significant susceptibility factor for inflammatory bowel disease. This karyotype often gives rise to relatively weak phenotypic characteristics of Turner's syndrome, which may be overlooked in short females with inflammatory bowel disease. The association of inflammatory bowel disease with Turner's syndrome may reflect the presence on the X chromosome of genes involved in disease pathogenesis. Linkage analysis studies, involving microsatellite markers on the X chromosome, are being performed.      

Reducing overdiagnosis by polygenic risk-stratified screening: findings from the Finnish section of the ERSPC

Background:

We derived estimates of overdiagnosis by polygenic risk groups and examined whether polygenic risk-stratified screening for prostate cancer reduces overdiagnosis.

Methods:

We calculated the polygenic risk score based on genotypes of 66 known prostate cancer loci for 4967 men from the Finnish section of the European Randomised Study of Screening for Prostate Cancer. We stratified the 72 072 men in the trial into those with polygenic risk below and above the median. Using a maximum likelihood method based on interval cancers, we estimated the mean sojourn time (MST) and episode sensitivity. For each polygenic risk group, we estimated the proportion of screen-detected cancers that are likely to be overdiagnosed from the difference between the observed and expected number of screen-detected cancers.

Results:

Of the prostate cancers, 74% occurred among men with polygenic risk above population median. The sensitivity was 0.55 (95% confidence interval (CI) 0.45–0.65) and MST 6.3 (95% CI 4.2–8.3) years. The overall overdiagnosis was 42% (95% CI 37–52) of the screen-detected cancers, with 58% (95% CI 54–65) in men with the lower and 37% (95% CI 31–47) in those with higher polygenic risk.

Conclusion:

Targeting screening to men at higher polygenic risk could reduce the proportion of cancers overdiagnosed.