Feasibility of tracking involuntary head movement for MRI using a coil as a magnetic dipole in a time-varying gradient.

Accurate tracking involuntary head movements is fairly a challenging problem in MR imaging of the brain. Though there are few techniques available to monitor the head movement of the subject for a prospective motion correction, it is still an unsolved problem in MRI. In this theoretical study, we aim to describe an analytical investigation to track head movement inside an MR scanner by calculating the change in induced voltage in the head-mounted coils during the execution of time-varying gradients. We derive an expression to calculate the change in induced voltage in a coil placed in a time-varying gradient. We also derive a general equation to investigate the changes in the induced voltage in a set of coils mounted onto the head for the planar position and orientation of the coils. Each coil is considered as a magnetic dipole with location and sensitivity vectors. The changes of the vectors can track the head movement in the MR scanner by measuring the changes in the induced voltage in the coils. The dipole concept is valid for a wide range of coils. The changes in induced voltage in the coils are linear due to small changes in pose of the head. Movement parameters are estimated from the induced voltage changes. If the random noise voltage is less than 100 µV, it does not significantly affect movement parameters because the change in induced voltage in the coils dominates over the small noise voltage. This method and array of the coils may provide a real-life solution to the long-standing problem of head motion during MRI.

Simultaneous EEG-fMRI: evaluating the effect of the cabling configuration on the gradient artefact.

EEG recordings made in combined EEG-fMRI studies are corrupted by gradient artefacts (GAs) resulting from the interaction of the EEG system with the time-varying magnetic field gradients used in MRI. The dominant contribution to the GA arises from interaction with the leads of the EEG cap and the human head, but artefacts are also produced in the cables used to connect the EEG cap to the amplifier. The aim of this study is to measure the effects of the connecting cable configuration on the characteristics of the GA. We measured the GA produced on two different cable configurations (a ribbon cable and a cable consisting of wires that are twisted together to form a cylindrical bundle) by gradient pulses applied on three orthogonal axes and also characterized the effect of each cable configuration on the GA generated by a multi-slice echo planar imaging sequence, as employed in typical EEG-fMRI studies. The results demonstrate that the cabling that connects the EEG cap to the amplifier can make a significant contribution to the GA recorded during EEG-fMRI studies. In particular, we demonstrate that the GA generated by a ribbon cable is larger than that produced using a twisted cable arrangement and that changes in the GA resulting from variation in the cable position are also greater for the ribbon cable.

Maternal mortality, birth with a health professional and distance to obstetric care in Indonesia and Bangladesh.

OBJECTIVE: To examine the relationship between distance to a health facility, consulting a health professional and maternal mortality. METHODS: Retrospective cohort study in Matlab, Bangladesh (1987-2005), to collect data on all pregnancies, births and deaths. In Java, Indonesia (2004-2005), an informant-based approach identified maternal deaths and a population-based survey sampled women who survived birth. Logistic regression was used to examine the influence of distance to a health facility and uptake of a health professional on odds of dying. RESULTS: Maternal mortality was 320 per 100 000 births (95% CI: 290, 353) in Indonesia and 318 per 100 000 (95% CI: 272, 369) in Bangladesh. Women who lived further from health centres in both countries were less likely to have their births attended by health professionals than those who lived closer. For women who were assisted by a health professional, the odds of dying increased with increasing distance from a health centre [odds ratio per km; Indonesia: 1.07 (95% CI: 1.02-1.11), Bangladesh: 1.47 (95% CI: 1.22-1.78)]. There was no evidence for an association between distance to a health centre and maternal death for women who were not assisted by a health professional. CONCLUSIONS: Even in settings where health services are relatively close to women's homes, distance to a health facility affects maternal mortality for women giving birth with a health professional. Women may only seek professional care in an emergency and may be unable to reach timely care when living far away from a health centre.

Occurrence and determinants of postpartum maternal morbidities and disabilities among women in Matlab, Bangladesh.

The burden of maternal ill-health includes not only the levels of maternal mortality and complications during pregnancy and around the time of delivery but also extends to the standard postpartum period of 42 days with consequences of obstetric complications and poor management at delivery. There is a dearth of reliable data on these postpartum maternal morbidities and disabilities in developing countries, and more research is warranted to investigate these and further strengthen the existing safe motherhood programmes to respond to these conditions. This study aims at identifying the consequences of pregnancy and delivery in the postpartum period, their association with acute obstetric complications, the sociodemographic characteristics of women, mode and place of delivery, nutritional status of the mother, and outcomes of birth. From among women who delivered between 2007 and 2008 in the icddr,b service area in Matlab, we prospectively recruited all women identified with complicated births (n=295); a perinatal mortality (n=182); and caesarean-section delivery without any maternal indication (n=147). A random sample of 538 women with uncomplicated births, who delivered at home or in a facility, was taken as the control. All subjects were clinically examined at 6-9 weeks for postpartum morbidities and disabilities. Postpartum women who had suffered obstetric complications during birth and delivered in a hospital were more likely to suffer from hypertension [adjusted odds ratio (AOR)=3.44; 95% confidence interval (CI)=1.14-10.36], haemorrhoids (AOR=1.73; 95% CI=1.11-3.09), and moderate to severe anaemia (AOR=7.11; 95% CI=2.03-4.88) than women with uncomplicated normal deliveries. Yet, women who had complicated births were less likely to have perineal tears (AOR=0.05; 95% CI=0.02-0.14) and genital prolapse (AOR=0.22; 95% CI=0.06-0.76) than those with uncomplicated normal deliveries. Genital infections were more common amongst women experiencing a perinatal death than those with uncomplicated normal births (AOR=1.92; 95% CI=1.18-3.14). Perineal tears were significantly higher (AOR=3.53; 95% CI=2.32-5.37) among those who had delivery at home than those giving birth in a hospital. Any woman may suffer a postpartum morbidity or disability. The increased likelihood of having hypertension, haemorrhoids, or anaemia among women with obstetric complications at birth needs specific intervention. A higher quality of maternal healthcare services generally might alleviate the suffering from perineal tears and prolapse amongst those with a normal uncomplicated delivery.

Assessment of non-marital sexual behaviours of men in Bangladesh: a methodological experiment using a modified confidential ballot-box method.

This study assessed the effectiveness of a modified ballot-box method (MBBM) in eliciting non-marital sexual behaviours compared with face-to-face interview (FTFI). A cross-sectional survey collected data from men aged 18-49 years in Bangladesh using a multistage cluster sampling method. In total, 3499 and 3623 respondents were interviewed by MBBM and FTFI, respectively. In the MBBM, pre-recorded questions were administered using a portable audio-cassette player with two pairs of headphones used concurrently by the respondent and the interviewer. Overall, 18% of the respondents had non-marital sexual exposure in the past year. The MBBM elicited higher responses of non-marital sex (adjusted odds ratio (aOR) 1.3, 95% confidence interval [CI]: 1.1, 1.5) compared with FTFI. The interview methods did not, however, revealed significant differences in response to condom-use rates and the number of non-marital sexual partners. The MBBM is more effective than the FTFI method in eliciting higher responses rates of non-marital sexual contacts and may be recommended for reliable estimates of sexual behaviours.

Inequity in maternal health-care services: evidence from home-based skilled-birth-attendant programmes in Bangladesh.

OBJECTIVE: To explore use-inequity in maternal health-care services in home-based skilled-birth-attendant (SBA) programme areas in Bangladesh. METHODS: Data from a community survey, conducted from February to May 2006, were analysed to examine inequities in use of SBAs, caesarean sections for deliveries and postnatal care services according to key socioeconomic factors. FINDINGS: Of 2164 deliveries, 35% had an SBA, 22.8% were in health facilities and 10.8% were by caesarean section. Rates of uptake of antenatal and postnatal care were 93% and 28%, respectively. There were substantial use-inequities in maternal health by asset quintiles, distance, and area of residence, and education of both the woman and her husband. However, not all inequities were the same. After adjusting for other determinants, the differences in the use of maternal health-care services for poor and rich people remained substantial [adjusted odds ratio (OR) 2.51 (95% confidence interval, CI: 1.68-3.76) for skilled attendance; OR 2.58 (95% CI: 1.28-5.19) for use of caesarean sections and OR 1.53 (95% CI: 1.05-2.25) for use of postnatal care services]. Complications during pregnancy influenced use of SBAs, caesarean-section delivery and postnatal care services. The number of antenatal care visits was a significant predictor for use of SBAs and postnatal care, but not for caesarean sections. CONCLUSION: Use of maternity care services was higher in the study areas than national averages, but a tremendous use-inequity persists. Interventions to overcome financial barriers are recommended to address inequity in maternal health. A greater focus is needed on the implementation and evaluation of maternal-health interventions for poor people.

Obstetric deaths in Bangladesh, 1996-1997.

OBJECTIVES: The purpose of this study was to measure and to describe obstetric deaths in Bangladesh. METHODS: We reviewed hospital records and interviewed health workers in clinic sites and field workers who cared for pregnant women. RESULTS: We obtained case reports of 28998 deaths of women aged 10-50, of which 8562 (29.5%) were maternal deaths. Most (7086, 82.8%) of these deaths were due to obstetric causes. The most common causes of direct obstetric death were eclampsia (34.3%), hemorrhage (27.9%), and obstructed and/or prolonged labor (11.3%). National direct obstetric death rate was estimated to be 16.9 per 100,000 women. CONCLUSIONS: Efforts to reduce fertility in Bangladesh have led to an estimated 49% reduction in the maternal mortality rate per 1000 women during the past 18 years. Variations in maternal mortality suggest the need to develop local strategies to improve obstetric care.

Injury-related deaths among women aged 10-50 years in Bangladesh, 1996-97.

BACKGROUND: Few studies have examined injury-related deaths among women in Bangladesh. We did a case-finding study to identify causes and the impact of intentional and unintentional injury-related deaths among women aged 10-50 years in Bangladesh. METHODS: Between 1996 and 1997, health care and other service providers at 4751 health facilities throughout Bangladesh were interviewed about their knowledge of deaths among women aged 10-50 years. In addition, at all public facilities providing inpatient service, medical records of women who died during the study period were reviewed. The reported circumstances surrounding each death were carefully reviewed to attribute the most likely cause of death. FINDINGS: 28,998 deaths among women aged 10-50 years were identified in our study, and, of these, 6610 (23%) were thought to be caused by intentional or unintentional injuries. About half (3317) of the injury deaths were attributable to suicide, 352 (5%) to homicide, 1100 (17%) to accidental injuries, and the intent was unknown for 1841 (28%) deaths. The unadjusted rate of suicides were higher in the Khulna administrative division (27.0 per 100,000) than the other four administrative divisions of Bangladesh (range 3.5-11.3 per 100,000). Poisoning (n=3971) was the commonest cause of injury-related death--60% of all injury deaths (6610) and 14% of all deaths (28,998). Other common causes of injury deaths in order of frequency were hanging or suffocation, road traffic accidents, burns, drowning, physical assault, firearm or sharp instrument injury, and snake or animal bite. INTERPRETATION: Intentional and unintentional injuries are a major cause of death among women aged 10-50 years in Bangladesh. Strategies to reduce injury-related deaths among women need to be devised.

Community-based self-reported symptoms of antepartum morbidities; the health burden and care-seeking patterns of rural Bangladeshi women.

In Bangladesh there is a dearth on information relating to complications during pregnancy. We followed up 1,019 pregnant women in rural Bangladesh sampled from all the 4 old administrative divisions of the country. Trained female interviewers visited households of the pregnant women at four-week intervals and interviewed them for their current pregnancy-related complications. Out of a total of 3,812 antepartum visits the percentage of reported symptoms of bleeding, fits and convulsions, excessive vomiting, fever >3 days, urinary problems, palpitations and symptomatic anemia were 0.3, 0.7, 1.4, 4.0, 26.8, 46.5 and 78.3 respectively. Morbidities were considered to cause a health burden if they imposed constraints in daily activities of the pregnant women and they were weighted according to intensity of the constraint. For each morbidity, the mean intensity of burden per episode and the population burden per 1,000 person months of observation of all the women were calculated. For common sustaining morbidities like symptomatic anemia and urinary problems the population burden was much heavier than that for more serious but rare morbidities like bleeding and convulsions. Among the visits in which the women had any symptoms, the percentages of care-seeking for less frequently reported morbidities such as fits and convulsions, bleeding, fever >3 days, excessive vomiting were about 74, 50, 34 and 33% respectively, whereas those for more commonly reported complications such as urinary problems, symptomatic anemia and palpitations were less than 20%. Care for these morbidities was mostly sought from untrained providers.