基于PC平台的扩展视野超声成像

扩展视野超声成像技术可以利用常规超声成像系统获得观察视野更大的图像,使得医生能够全面了解被成像部位的解剖结构,从而得出更客观和准确的诊断结果.本文给出一种基于PC平台的扩展视野超声成像系统及图像配准和拼接的快速算法.实验证明此算法不仅有较好的成像精度,并且有望实现实时成像.     

Effect of Training on Qualitative Mammographic Density Assessment

PurposeThe aim of this study was to evaluate the accuracy of visual mammographic breast density assessment and determine if training can improve this assessment, to compare the accuracy of qualitative density assessment before and after training with a quantitative assessment tool, and to evaluate agreement between qualitative and quantitative density assessment methods.MethodsConsecutive screening mammograms performed over a 4-month period were visually assessed by two study breast radiologists (the leads), who selected 200 cases equally distributed among the four BI-RADS density categories. These 200 cases were shown to 20 other breast radiologists (the readers) before and after viewing a training module on visual density assessment. Agreement between reader assessment and lead radiologist assessment was calculated for both reading sessions. Quantitative volumetric density of the 200 mammograms, determined using a commercially available tool, was compared with both sets of reader assessment and with lead radiologist assessment.ResultsCompared with lead radiologist assessment, reader accuracy of breast density assessment increased from 65% before training to 72% after training (odds ratio, 1.41; P < .0001). Training specifically improved assignment to BI-RADS categories 1 (P < .0001) and 4 (P < .10). Compared with quantitative assessment, reader accuracy showed statistically nonsignificant improvement with training (odds ratio, 1.1; P = .26). Substantial agreement between qualitative and quantitative breast density assessment was demonstrated (κ = 0.78).ConclusionsTraining may improve the accuracy of mammographic breast density assessment. Substantial agreement between qualitative and quantitative breast density assessment exists.     

Fluorescence guided resection (FGR): A primer for oncology

Curative treatment for most cancer patients requires surgical removal of the tumor. Often though, residual disease is left behind negatively impacting tumor control and survival. Florescent Guided resection (FGR) is one type of Image Guided Surgery that offers the potential to improve outcomes for these patients. Currently, during FGR, a probe is preoperatively applied and allowed to concentrate in the tumor bed. At surgery appropriate light is applied to generate fluorescence which allows the surgeon to better visualize tumor extent. This improved visualization has translated both into enhanced rates for resection but also diminished rates of morbidity as less normal tissue need be removed to achieve negative margins. This paper will summarize the theory and practise of FGR as currently applied in clinical oncology including select outcomes and limitations of technique and technology.     

Outcomes of bisphosphonate therapy in kidney transplant recipients: a systematic review and meta‐analysis

Mineral and bone disorders that precede kidney transplantation are exacerbated in the post‐transplant setting by tertiary hyperparathyroidism and immunosuppressive regimens. Bone mineral density (BMD) decreases following transplantation, leading to increased fracture risk. The effect of bisphosphonates on fracture is unknown. The aim of this study was to update estimates of change in BMD and fracture rates in bisphosphonate‐treated kidney transplant recipients through meta‐analysis. Studies comparing bisphosphonate therapy to standard of care were included if follow‐up duration was more than 6 months. We performed random‐effects meta‐analysis to determine the effect of bisphosphonates on lumbar spine and femoral neck BMD and fracture rates. Bisphosphonates improved femoral neck and lumbar spine BMD compared with controls (0.055 g/cm², 95% CI 0.012–0.099 and 0.053 g/cm², 95% CI 0.032–0.074, respectively) without adversely affecting serum creatinine or calcium. This corresponded to an unweighted improvement in BMD of 6.0% and 7.4%, respectively. There was no difference in fracture incidence in the two groups. Bisphosphonate therapy in kidney transplant recipients is associated with a statistically significant improvement in BMD at the lumbar spine and femoral neck. There was no difference in fracture incidence. Bisphosphonates did not adversely affect allograft dysfunction or serum calcium levels.     

强骨抗萎方增强尾吊大鼠承重骨骨矿密度

目的 研究中药复方-强骨抗萎方(QGKWP)对尾吊大鼠骨代谢的影响.方法 21只雄性SD大鼠随机分为对照组(Con),尾吊组(TS)和强骨抗萎方处理组(QGKWP),分别填喂2.5 mL生理盐水或30mg/g中药复方,早晚各1次.每周利用双能X射线吸收测定法检测其骨密度.实验28天后,取血清测定碱性磷酸酶(ALP)、骨碱性磷酸酶(BALP)、骨γ碳氧谷氨酸蛋白(BGLAP)和脱氧吡啶(DPD).同时检测承重骨力学性能、骨干重和骨灰重.免疫组化检测骨Ⅰ型胶原(type Ⅰ collagen),骨钙素(osteocalcin)和骨桥蛋白(osteopontin)含量.结果 与尾吊组相比,强骨抗萎方组股骨、胫骨和腰椎骨密度显著升高,血清ALP和BGLAP表达增加.QGKWP还能明显升高尾吊大鼠股骨Ⅰ型胶原和骨桥蛋白的表达.结论 强骨抗萎方可部分逆转由尾吊引起的失重效应,在对抗骨丢失方面有潜在应用价值.     

基于电控旋转磁场与非迭代几何算法的电磁跟踪方法仿真研究

目的针对传统电磁跟踪方法存在的依赖磁场模型具体磁感应强度值、迭代算法繁琐的问题,提出一种采用非迭代几何算法的电控旋转磁场跟踪方法,以避免模型误差、简化定位算法。方法采用三轴正交磁场源,通过控制磁场源三轴激励电流强度实现合成最大磁感应强度矢量在空间中遍历旋转,根据矢量指向三轴磁传感器时的旋转角利用非迭代几何算法进行定位,对该方法进行了仿真研究。结果仿真半径为0.3 m时,平均位置误差为0.32 cm,方差为0.02,定位时间为0.54 s。结论基于电控旋转磁场与非迭代几何算法的电磁跟踪方法可以较准确地定位传感器,具有定位速度快、性能稳定的潜在优势,值得进一步优化提高性能以满足介入式微创手术临床实用要求。     

Giant panda (Ailuropoda melanoleuca) sperm morphometry and function after repeated freezing and thawing

This work examines the effects of subsequent cycles of freezing–thawing on giant panda (Ailuropoda melanoleuca) sperm morphometry and function, and assesses whether density‐gradient centrifugation (DGC) can increase the number of freezing–thawing cycles this sperm can withstand. A sperm sample was collected by electroejaculation from a mature giant panda and subjected to five freezing–thawing cycles. Although repeated freezing–thawing negatively affected (P < 0.05) sperm motility and membrane integrity, in both nonselected and DCG‐selected sperm samples, >60% of the sperm cells in both treatments showed acrosome integrity even after the fifth freezing cycle. In fresh semen, the sperm head length was 4.7 μm, the head width 3.6 μm, area 14.3 μm² and perimeter length 14.1 μm. The present results suggest that giant panda sperm trends to be resistant to repeated freezing–thawing, even without DGC selection.     

Metabolic syndrome and its association with obesity and lifestyle factors in Sudanese population

Although modern life style factors affecting health is a crucial problem globally, little information about metabolic syndrome (MetS) is available for the Sudanese population. With this consideration the study was planned to assess the prevalence of MetS among young people of Sudan and their association with obesity and lifestyle factors. Serum lipid profile, blood glucose and clinically established parameters for obesity were assessed in 179 young adult male and 201 females at National Ribat University, Sudan. Relevant statistical test were applied using SPSS software. Based on anthropometric measurements, 137 students were obese. Amongst the 243 non-obese students 5 were under weight, 135 normal weight and 103 were over weight. In the study population, 317 students were normal (83.4%) and 63 students had MetS (16.6%) as defined by ATP III definition of MetS classification. MetS was found only in obese individuals (45.98%) and no case was detected in underweight, normal and overweight individual. The mean of cholesterol level in subjects with MetS was 159 as compared to those without it (149.93). Life style modification as healthy diet, regular exercise and preventive strategies may help reduce MetS, thus improving general health conditions in young individuals of Sudan.     

Effect of Extended 30 μg Ethinyl Estradiol with Continuous Low-Dose Ethinyl Estradiol and Cyclic 20 μg Ethinyl Estradiol Oral Contraception on Adolescent Bone Density: A Randomized Trial

Study ObjectiveTo compare changes in lumbar spine bone mineral density after 12 months of a 91-day extended regimen or 28-day combined oral contraceptive with those in a healthy reference group not using hormonal contraceptives.DesignPhase 2, multicenter, open-label, randomized, controlled study.SettingForty-five academic centers, clinical research centers, and community practices in the United States.ParticipantsEight hundred twenty-nine postmenarcheal adolescent girls aged 12-18 years.InterventionsAdolescents were randomly assigned to 91-day levonorgestrel (LNG)/ethinyl estradiol (EE) extended regimen (84 days of LNG 150 μg/EE 30 μg with 7 days of EE 10 μg [LNG/EE extended regimen]) or 28 days of LNG/EE (21 days of LNG 100 μg/EE 20 μg with 7 days of placebo [LNG/EE 21/7]) for 12 months. A reference group not seeking hormonal contraception was also evaluated.Main Outcome MeasuresThe primary end point was mean percent change in lumbar spine bone mineral density measured using dual-energy x-ray absorptiometry.ResultsOf 1361 adolescents randomized/enrolled, 829 were included in the primary analysis. Mean changes in lumbar spine bone mineral density were +2.26% with LNG/EE extended regimen, +1.45% with LNG/EE 21/7, and +2.50% in the reference group. Noninferiority of the LNG/EE extended regimen compared with the reference group was shown. A statistically significant treatment difference was found between LNG/EE 21/7 and the reference group (1.05%; 95% confidence interval, 0.61%-1.49%) but not between LNG/EE extended regimen and the reference group (0.23%; 95% confidence interval, −0.20% to 0.67%). No new safety signals were noted.ConclusionCompared with the reference group, bone accrual was statistically significantly lower among LNG/EE 21/7 users but not among LNG/EE 30-μg extended regimen users. Additional research is needed to clarify the clinical relevance of these findings.