医学超声图像三域滤波去噪算法

针对视频格式的医学超声图像序列,提出了一种同时利用空间域、灰度域和时间域的相关信息的三域滤波算法。首先对每一帧图像,充分利用空间域和灰度域的相关信息构建自适应邻域,接着进行空间域和灰度域加权滤波,最后利用相邻帧之间的时域相关性进行时域加权滤波。三个域的滤波均采用高斯核函数加权,从而减小了滤波结果对阈值选取的敏感度,提高了算法的稳定性。实验结果表明,三域滤波算法能有效地抑制图像中的噪声,并保留边缘细节,有利于图像的特征提取、识别和分析。     

Increased risk of leukaemia in patients with juvenile chronic arthritis treated with chlorambucil

Two cases of acute leukaemia have developed in a group of 77 patients treated with chlorambucil (Chl) because of severe juvenile chronic arthritis. The total follow-up from the beginning of Chl treatment in these patients was 560 years, indicating a highly increased risk of leukaemia. Despite favourable results, especially in patients with secondary amyloidosis, Chl should only be used in selected cases.     

Prevalence and aetiology of neurological impairment in extremely low birthweight infants

Objective : To determine the prevalence and perinatal predictors of cerebral palsy, intellectual impairment, visual impairment and deafness in a cohort of extremely low birthweight (ELBW) infants at two years of age.
Methodology : The study population comprised 199 of the 224 (89%) ELBW infants managed at the Mater's Mothers Hospital, Brisbane, between July 1977 and February 1990 and who survived to two years. The prevalence of cerebral palsy, intellectual impairment, blindness and deafness was measured by clinical, psychometric and audiological assessment and the association with 24 risk factors examined.
Results : Cerebral palsy occurred in 20 children (10%). Risk of cerebral palsy was associated with ventricular dilatation, intraventricular haemorrhage, necrotizing enterocolitis and multiple birth, though only ventricular dilatation (OR 4.41; 95% Cl 1.32-14.8) remained significant in the adjusted analysis. Intellectual impairment occurred in 20 children (10%) and was independently associated with ventricular dilatation (OR 15.0; 95% Cl 2.2-102.8), ventilation F _iO₂ >80% (OR 3.4; 95% Cl 1.01-11.5), vaginal delivery (OR 3.5; 95% Cl 1.09-11.4) and male sex (OR 6.1; 95% Cl 1.67-22.3). No perinatal predictor was statistically associated with risk of deafness. Retinopathy of prematurity (OR 36.9; 95% Cl 2.8-495.5) was associated with risk of later visual impairment.
Conclusions : Intellectual impairment was associated with a broad range of perinatal variables. Cerebral palsy was associated with fewer variables, all of which were also associated with intellectual impairment. Neurologic injury was associated with male sex and multiple birth, which are not biological insults themselves, but may be markers of susceptibility to injury.     

Abnormal anatomy of the lumbosacral region imaged by magnetic resonance in children with anorectal malformations

OBJECTIVE: To investigate the frequency of lumbosacral anomalies, the association with urogenital abnormalities, and the correlation with defaecation pattern by magnetic resonance imaging (MRI). METHODS: A prospective analysis was performed of routine MRI in patients with anorectal malformations. Between 1990 and 1994, MRI was performed in 43 such patients: 31 boys and 12 girls. Twenty four had a high anorectal malformation, 16 had a low anorectal malformation, and three had Currarino's triad. MRI was performed before reconstruction in 26, and postoperatively in 17. Urogenital anomalies were found in 21. RESULTS: Abnormalities of the spinal cord and spine were found with MRI in 20 patients (46.5%); caudal regression syndrome in 10, tethered cord in two, a combination of both in three, and other spinal anomalies in five. These anomalies were found in 30% of the patients with low anorectal malformations, and in 50% with high anorectal malformations. In patients with urogenital malformations, MRI more often showed spinal anomalies (13/21, 62%) than in patients without (7/22, 32%). In high anorectal malformations, defaecation was more often a problem in patients with spinal anomalies (12/15, 80%) than in patients without (2/8, 25%). CONCLUSIONS: Spinal anomalies in the lumbosacral region were found with MRI in 46.5% of patients with anorectal malformations. Since presence of these anomalies seems to be related to clinical outcome, MRI should be performed routinely in all such patients.     

Biofeedback training in chronic constipation

Twenty nine patients, aged 5-16 years, were studied to evaluate whether biofeedback training is effective in treating children with chronic constipation and encopresis; the clinical outcome at six weeks and 12 months was also evaluated. Patients received on average five biofeedback training sessions. The existence of external anal contraction or decreased rectal sensation in 16 (55%) and eight (27%) of the children, respectively was identified on manometry. After biofeedback training, 26 (90%) of the patients learned to relax the external anal sphincter; 18 (63%) normalised rectal sensation. The training resulted in a significant increase in defecation frequency and a significant decrease in encopresis. At six weeks, 16 (55%) of the patients were clinically symptom free. At follow up after 12 months the results were sustained. Only three patients showed a relapse within six months, of whom two were successfully treated with one extra training session. Biofeedback training might be a useful therapeutical approach in children with chronic constipation and encopresis.     

Three independent factors predicted adherence in a randomized controlled trial of resistance exercise training among prostate cancer survivors

OBJECTIVE: To examine predictors of adherence in a randomized controlled trial of resistance exercise training (RET) in prostate cancer survivors receiving androgen deprivation therapy. STUDY DESIGN AND SETTING: A randomized controlled trial conducted at fitness centers in Ottawa and Edmonton, Canada. Prostate cancer survivors (n=155) completed measures of social cognitive variables, quality of life (QOL), behavior, and fitness before being randomized to either an exercise (n=82) or control (n=73) group. The exercise group was asked to perform supervised RET three times per week for 12 weeks. RESULTS: The exercise group attended 28.2 of the 36 (78.3%) RET sessions. Univariate analyses revealed eight different significant (Ps <.05) predictors of exercise adherence including exercise stage of change, intention, age, QOL, fatigue, subjective norm, leg-press test, and perceived behavioral control. A multivariate analysis indicated that there were three independent predictors of adherence that explained 20.4% of the variance: exercise stage of change (beta=0.26; P=.013), age (beta=-0.22; P=.037), and intention (beta=0.19; P=.073). CONCLUSION: Exercise adherence in the trial was very good but not optimal. Adherence was predicted by variables from many different categories including social cognitive, QOL, behavioral, fitness, and demographic. These findings may have important implications for maximizing adherence during clinical trials of exercise in prostate cancer survivors.     

Predictors of adherence and contamination in a randomized trial of exercise in colorectal cancer survivors

The purpose of this study was to examine predictors of exercise adherence (i.e. exercise in the intervention group) and exercise contamination (i.e. exercise in the control group) in a randomized controlled trial of home-based exercise in colorectal cancer survivors. At baseline, 102 participants completed measures of the theory of planned behavior, personality, past exercise, exercise stage of change, physical fitness, and medical/demographics and then were randomly assigned in a 2:1 ratio to an exercise (n=69) or control (n=33) group. Exercise was monitored weekly for 16 weeks using self-reports by telephone. Ninety-three (91%) participants completed the trial. Adherence was 76% in the exercise group and contamination was 52% in the control group. Hierarchical stepwise regression analyses indicated that baseline exercise stage of change (beta=0.35; p=0.001), employment status (beta=-0.28; p=0.010), treatment protocol (beta=-0.26; p=0.018), and perceived behavioral control (beta=0.20; p=0.055) explained 39.6% of the variance in exercise adherence. Intentions (beta=0.36; p=0.049) and baseline exercise stage of change (beta=0.30; p=0.095) explained 29.9% of the variance in exercise contamination. These findings may have implications for conducting clinical trials of exercise in colorectal cancer survivors and for promoting exercise to colorectal cancer survivors outside of clinical trials.     

Thermal burn fatalities in the workplace,United States, 1992 to 1999

The purpose of this study was to present the epidemiology of thermal burn fatalities in the workplace in the United States between 1992 and 1999. Data on fatal thermal burn injuries in the United States between 1992 through 1999 were obtained from the Bureau of Labor Statistics Census of Fatal Occupational Injuries. Between 1992 and 1999, 1,189 fatal thermal burns occurred in the workplace (0.11 deaths/100,000 workers per year). Mortality increased with age, with those over 65 years of age having the greatest rate of death (0.20/100,000). Workers in the mining industry and transportation and public utilities had the highest rates of fatal thermal burns. Occupational categories with the highest rates included "extractive occupations" (eg, miners, explosives workers) and "transportation and material movers" (eg, truck drivers). The specific occupations with the highest rates were airplane pilots and navigators, furnace, kiln, and oven operators, and firefighters. Most decedents were operating vehicles or involved in "other transportation operations" at the time of the incident. The majority of injurious incidents occurred on "industrial premises" or the "street and highway." Efforts to prevent fatal occupational thermal burn injuries should focus on older workers and those in occupations with frequent exposure to potential sources of thermal injury. Further study of nonfatal thermal burns in the workplace is needed because patterns of fatal burn injury may not reflect patterns of occupational burn injury overall.