Progress towards in vitro quantitative imaging of human femur using compound quantitative ultrasonic tomography

The objective of this study is to make cross-sectional ultrasonic quantitative tomography of the diaphysis of long bones. Ultrasonic propagation in bones is affected by the severe mismatch between the acoustic properties of this biological solid and those of the surrounding soft medium, namely, the soft tissues in vivo or water in vitro. Bone imaging is then a nonlinear inverse-scattering problem. In this paper, we showed that in vitro quantitative images of sound velocities in a human femur cross section could be reconstructed by combining ultrasonic reflection tomography (URT), which provides images of the macroscopic structure of the bone, and ultrasonic transmission tomography (UTT), which provides quantitative images of the sound velocity. For the shape, we developed an image-processing tool to extract the external and internal boundaries and cortical thickness measurements. For velocity mapping, we used a wavelet analysis tool adapted to ultrasound, which allowed us to detect precisely the time of flight from the transmitted signals. A brief review of the ultrasonic tomography that we developed using correction algorithms of the wavepaths and compensation procedures are presented. Also shown are the first results of our analyses on models and specimens of long bone using our new iterative quantitative protocol.     

Socio-cultural and problematic context of AIDS prevention in Africa: some observations drawn from the case of the Mossi society in Burkina Faso

On September 30, 1988, Burkina Faso had only 26 reported cases of AIDS. By March 20, 1992, there were 1263 reported cases. Burkina Faso officials focus on AIDS prevention. Heterosexual transmission of HIV predominates in Africa. There are observable behaviors, practices, and beliefs of the Mossi society in Burkina Faso which expose people to HIV or facilitate its transmission. The Mossi is a hierarchical society with the chief having absolute power. The head of the family has absolute power over the women and children. Polygamy is common. The Mossi describe their past as an earthly paradise with no AIDS. This magnificent past allows a faulty perception of one's risk. The cultural tradition of a widow marrying her husband's younger brother appears to be a risk for HIV transmission. This custom is forced on the widow because in the Mossi society a woman with no husband is nothing. If a man dies of AIDS and has infected some or all of his wives, the younger brother(s) will in turn become infected. On the other hand, a younger brother may be HIV infected and, upon marrying his deceased brother's wife or wives, he infects her or them. Uncircumcised males and females are stigmatized and marginalized in the Mossi society. Nonsterilized instruments are used to perform genital mutilations and are used on several persons. Traditional vaccinations by cutaneous scarification and treatment of sores and cutaneomucous lesions are other possible ways HIV may be transmitted among the Mossi. Preparing the cadaver is done without gloves and, in cases of AIDS, exposes the preparers to open lesions. Serious obstacles to HIV prevention campaigns are erroneous beliefs about the modes of HIV transmission, the acculturated fatalistic attitude among youth that one contracts AIDS whether or not one takes precautions, and the attitude that AIDS comes from elsewhere.     

Adaptive reconstruction of phased array MR imagery.

An adaptive implementation of the spatial matched filter and its application to the reconstruction of phased array MR imagery is described. Locally relevant array correlation statistics for the NMR signal and noise processes are derived directly from the set of complex individual coil images, in the form of sample correlation matrices. Eigen-analysis yields an optimal filter vector for the estimated signal and noise array correlation statistics. The technique enables near-optimal reconstruction of multicoil MR imagery without a-priori knowledge of the individual coil field maps or noise correlation structure. Experimental results indicate SNR performance approaching that of the optimal matched filter. Compared to the sum-of-squares technique, the RMS noise level in dark image regions is reduced by as much as the square root of N, where N is the number of coils in the array. The technique is also effective in suppressing localized motion and flow artifacts.     

Non‐invasive assessment of liver fibrosis by stiffness measurement in patients with chronic hepatitis B

Background: The need for new non‐invasive tools to assess liver fibrosis in chronic liver diseases has been largely advocated. Liver stiffness measurement (LSM) using transient elastography (FibroScan^®, Echosens^?) has been shown to be correlated to liver fibrosis in various chronic liver diseases. This study aims to assess its diagnosis accuracy in patients with chronic hepatitis B. Patients and methods: We prospectively enrolled 202 patients with chronic hepatitis B in a multicentre study. Patients underwent liver biopsy (LB) and LSM. METAVIR and Ishak liver fibrosis stages were assessed by two pathologists. Results: LSM or LB was considered unreliable in 29 patients. Statistical analysis was conducted in 173 patients. LSM was significantly (P<0.001) correlated with METAVIR (r=0.65) and Ishak fibrosis stage (0.65). The area under receiver‐operating characteristic curves were 0.81 (95% confidence intervals, 0.73–0.86) for F≥2, 0.93 (0.88–0.96) for F≥3 and 0.93 (0.82–0.98) for F=4. Optimal LSM cut‐off values were 7.2 and 11.0 kPa for F≥2 and F=4, respectively, by maximizing the sum D of sensitivity and specificity, and 7.2 and 18.2 kPa by maximizing the diagnosis accuracy. Conclusion: In conclusion, LSM appears to be reliable for detection of significant fibrosis or cirrhosis in HBV patients and cut‐off values are only slightly different from those observed in HCV patients.     

Process evaluation improves delivery of a nutrition‐sensitive agriculture programme in Burkina Faso

Evidence is emerging from rigorous evaluations about the effectiveness of nutrition‐sensitive agriculture programmes in improving nutritional outcomes. Additional evidence can elucidate how different programme components and pathways contribute and can be optimized for impact. The International Food Policy Research Institute, with Helen Keller International, designed a comprehensive framework to evaluate the delivery, utilization, and impact of Helen Keller International's enhanced homestead food production programme in Burkina Faso. After 18 months of implementation, a process evaluation was conducted to examine programme impact pathways, using key informant and semistructured interviews with implementing agents and beneficiaries, and with residents of control communities. Data were analyzed by International Food Policy Research Institute and reviewed with project managers and partners through multiple workshops to identify opportunities to strengthen implementation. Findings illuminated gaps between intended and actual delivery schemes, including input constraints, knowledge gaps among community agents in agriculture and young child nutrition practices, and lower than expected activity by community volunteers. In response, staff developed measures to overcome water constraints and expand vegetable and poultry production, retrained volunteers in certain techniques of food production and counselling for nutrition behaviour change, added small incentives to motivate volunteers, and shaped both immediate and long‐term changes to the programme model. Working closely with International Food Policy Research Institute on the evaluation activities also expanded the repertoire of research methods and skills of Helen Keller International staff. Process evaluation can strengthen programme delivery, utilization, and design. Collaboration between researchers and implementers can improve programme effectiveness, project staff capacity, and advance delivery science.     

Patient-reported outcomes with direct-acting antivirals for the treatment of chronic hepatitis C: current knowledge and outstanding issues

Introduction: Patient-reported outcomes (PROs) play a key role in the evaluation of direct-acting antivirals (DAA) for the treatment of chronic hepatitis C (CHC). The main PROs of particular interest in CHC include quality of life (QoL), fatigue and its functional repercussions, work productivity, adherence to treatment, and risk behaviors.

Areas covered: This study summarizes the body of knowledge regarding PROs in CHC with DAA-based therapy. Outstanding related issues are presented and discussed.

Expert commentary: Current knowledge on PROs with CHC mainly relies on clinical trial data. All-oral DAA regimens are associated with minimal QoL impairment and symptom burden, rapid recovery once treatment has ended, and improvement in PROs for a non-negligible proportion of treated patients, especially HCV clearers. Further research is needed to analyze both long-term changes in PROs, and PROs in specific populations including people who use drugs, comorbid patients and patients at risk of reinfection.     

The tip of the iceberg: evidence of seasonality in institutional maternal mortality and implications for health resources management in Burkina Faso

AIMS: The aims of this study were to investigate seasonal patterns of institutional maternal deaths and complications, and to test for an association with malaria seasons, rainfall, and household income. METHODS: A systematic case review of hospital records in the Boucle du Mouhoun health region (Burkina Faso) was conducted over a 2-year period. A statistical smoothing procedure (T4253H) and Freedman's test were used to investigate seasonality and association with malaria, rainfall or household income variations. RESULTS: The data consistently showed the greatest rates of maternal deaths, eclampsia and haemorrhage cases during the dry season, which is the low malaria transmission season, and the period of the year when households have most money available and the lowest opportunity cost of travelling to seek medical attention, suggesting that financial and geographical barriers may be major underlying factors. CONCLUSIONS: The management both of health resources in hospital and of referral systems should accommodate cyclical variations in the presentation of maternal complications. Effective mechanisms are needed to help reduce the significant barriers to uptake faced by women and their families at particular times of the year.