Artifacts seen during CT pelvimetry: implications for digital systems with scanning beams

During computed tomography (CT) pelvimetry of two pregnant women, bony abnormalities of the fetuses were noted on the scout images that were not confirmed at delivery. To explore the cause of these artifacts, specimen long bones were manipulated in various ways during CT scout imaging. Artifacts like those seen during in vivo imaging were found to be caused by motion of the object. The CT scout view is an example of an image produced by a digital system that uses a scanning beam. This type of digital system is being used for several types of body imaging including screening for scoliosis and chest radiography. Attention to motion artifacts should decrease diagnostic errors and aid further development of these systems.     

Cerebral blood flow relationships associated with a difficult tone recognition task in trained normal volunteers

Tone recognition is partially subserved by neural activity in the right frontal and primary auditory cortices. First we determined the brain areas associated with tone perception and recognition. This study then examined how regional cerebral blood flow (rCBF) in these and other brain regions correlates with the behavioral characteristics of a difficult tone recognition task. rCBF changes were assessed using H2(15)O positron emission tomography. Subtraction procedures were used to localize significant change regions and correlational analyses were applied to determine how response times (RT) predicted rCBF patterns. Twelve trained normal volunteers were studied in three conditions: REST, sensory motor control (SMC) and decision (DEC). The SMC-REST contrast revealed bilateral activation of primary auditory cortices, cerebellum and bilateral inferior frontal gyri. DEC-SMC produced significant clusters in the right middle and inferior frontal gyri, insula and claustrum; the anterior cingulate gyrus and supplementary motor area; the left insula/claustrum; and the left cerebellum. Correlational analyses, RT versus rCBF from DEC scans, showed a positive correlation in right inferior and middle frontal cortex; rCBF in bilateral auditory cortices and cerebellum exhibited significant negative correlations with RT These changes suggest that neural activity in the right frontal, superior temporal and cerebellar regions shifts back and forth in magnitude depending on whether tone recognition RT is relatively fast or slow, during a difficult, accurate assessment.      

糖尿病与重症牙周病相关的证据

数据来源：检索MEDLINE数据库从1970年1月至2003年10月出版的所有文献．并手工检索参考文献中的相关文献。纳入标准：以人为对象的临床试验或观察性研究，且以英语发表的文献。数据提取和合成：由3位作者分别提取数据，意见不同则由讨论解决。记录一系列指标：菌斑指数（PI）、牙石指数、牙龈指数（GI）、探诊出血指数（BOP）、牙周探诊深度（PPD）、临床附着丧失（CAL）、牙龈退缩、牙周指数和骨丧失指数。用血液中糖化血红蛋白百分浓度显示糖尿病控制与否。评估各牙周参数的整体差异，并应用固定效应模型或随机效应模型计算相应的95％CI。用Q检验进行同质性检验。用漏斗图检测发表偏倚。结果：18个横断面对照研究、3个前瞻性队列研究和2个临床试验的基线资料入选。