Respiration resolved imaging with continuous stable state 2D acquisition using linear frequency SWEEP.

PURPOSE: To investigate the potential of continuous radiofrequency (RF) shifting (SWEEP) as a technique for creating densely sampled data while maintaining a stable signal state for dynamic imaging. METHODS: We present a method where a continuous stable state of magnetization is swept smoothly across the anatomy of interest, creating an efficient approach to dense multiple 2D slice imaging. This is achieved by introducing a linear frequency offset to successive RF pulses shifting the excited slice by a fraction of the slice thickness with each successive repeat times (TR). Simulations and in vivo imaging were performed to assess how this affects the measured signal. Free breathing, respiration resolved 4D volumes in fetal/placental imaging is explored as potential application of this method. RESULTS: The SWEEP method maintained a stable signal state over a full acquisition reducing artifacts from unstable magnetization. Simulations demonstrated that the effects of SWEEP on slice profiles was of the same order as that produced by physiological motion observed with conventional methods. Respiration resolved 4D data acquired with this method shows reduced respiration artifacts and resilience to non-rigid and non-cyclic motion. CONCLUSIONS: The SWEEP method is presented as a technique for improved acquisition efficiency of densely sampled short-TR 2D sequences. Using conventional slice excitation the number of RF pulses required to enter a true steady state is excessively high when using short-TR 2D acquisitions, SWEEP circumvents this limitation by creating a stable signal state that is preserved between slices.

Whole body fat: content and distribution.

Obesity and its co-morbidities, including type II diabetes, insulin resistance and cardiovascular diseases, have become one of the biggest health issues of present times. The impact of obesity goes well beyond the individual and is so far-reaching that, if it continues unabated, it will cause havoc with the economies of most countries. In order to be able to fully understand the relationship between increased adiposity (obesity) and its co-morbidity, it has been necessary to develop proper methodology to accurately and reproducibly determine both body fat content and distribution, including ectopic fat depots. Magnetic Resonance Imaging (MRI) and Spectroscopy (MRS) have recently emerged as the gold-standard for accomplishing this task. Here, we will review the use of different MRI techniques currently being used to determine body fat content and distribution. We also discuss the pros and cons of MRS to determine ectopic fat depots in liver, muscle, pancreas and heart and compare these to emerging MRI techniques currently being put forward to create ectopic fat maps. Finally, we will discuss how MRI/MRS techniques are helping in changing the perception of what is healthy and what is normal and desirable body-fat content and distribution.

Motion-compensation techniques in neonatal and fetal MR imaging.

SUMMARY: Fetal and neonatal MR imaging is increasingly used as a complementary diagnostic tool to sonography. MR imaging is an ideal technique for imaging fetuses and neonates because of the absence of ionizing radiation, the superior contrast of soft tissues compared with sonography, the availability of different contrast options, and the increased FOV. Motion in the normally mobile fetus and the unsettled, sleeping, or sedated neonate during a long acquisition will decrease image quality in the form of motion artifacts, hamper image interpretation, and often necessitate a repeat MR imaging to establish a diagnosis. This article reviews current techniques of motion compensation in fetal and neonatal MR imaging, including the following: 1) motion-prevention strategies (such as adequate patient preparation, patient coaching, and sedation, when required), 2) motion-artifacts minimization methods (such as fast imaging protocols, data undersampling, and motion-resistant sequences), and 3) motion-detection/correction schemes (such as navigators and self-navigated sequences, external motion-tracking devices, and postprocessing approaches) and their application in fetal and neonatal brain MR imaging. Additionally some background on the repertoire of motion of the fetal and neonatal patient and the resulting artifacts will be presented, as well as insights into future developments and emerging techniques of motion compensation.

The demographic impact of Partition in the Punjab in 1947.

We use data from the 1931, 1941, and 1951 censuses of India and the 1951 census of Pakistan to examine the demographic consequences of Partition in the Punjab in 1947. Had growth rates for the period 1931-41 for the Punjab as a whole continued to 1951, the population of the Punjab would have been 2.9 million larger than that recorded in 1951. Population losses from migration and mortality above age 20 were approximately 2.7 million greater between 1941 and 1951 than would have been predicted by loss rates between 1931 and 1941. We estimate a net Partition-related population movement out of the combined Punjab of about 400,000. We conclude from several lines of analysis that Partition-related population losses in the Punjab, either from deaths or unrecorded migration, were in the range 2.3-3.2 million. Partition was also marked by a dramatic religious homogenization at the district level.

Perinatal mortality in high risk pregnancy: a prospective study of preventable factors.

The present study was undertaken to identify the preventable factors operative in high fetal and neonatal losses. Over a period of one year, of total of 1,600 consecutive deliveries, 1,107 were considered to be at-risk: there were 33 fetal and 31 early neonatal deaths with an overall perinatal mortality rate of 40/1,000 births. Perinatal mortality was higher in mothers who had received inadequate antenatal care and/or with bad obstetric history. Major maternal and obstetric factors associated with a high PMR were: advancing maternal age and parity, antepartum hemorrhage, diabetes, anemia, instrument and vaginal breech delivery. Overall cesarean section rate was 16.9%. Infants with a gestational age of less than 37 weeks and/or of birth weight of less than 2,500 g contributed for 56.2% and 68.7% of the total perinatal losses respectively. PMR was three fold higher among twins compared with singleton births. Identifiable causes of perinatal deaths observed were: asphyxia (31%), congenital anomalies (18.7%), sepsis (18.7%) and low birth weight (25%). It would appear that preventable factors are operative in over two third of the cases of perinatal loss and better maternal health, obstetric and neonatal care can improve the perinatal outcome in majority of the cases.

Community care for patients with schizophrenia one year after hospital discharge.

OBJECTIVES: To document the circumstances and care of patients with schizophrenia who had recently been discharged from local psychiatric inpatient services, and to establish the extent to which misgivings about community care might be justified. DESIGN: Cross sectional surveys with review of case notes. Follow up interviews with questionnaires administered one year after discharge. SETTING: Two inner London districts (West Lambeth and Lewisham) with high levels of social deprivation and at different stages of developing community services. PATIENTS: 90 and 50 patients in the two services respectively, aged 18 to 65, who satisfied the Research Diagnostic Criteria for schizophrenia and who were discharged from inpatient services. MAIN OUTCOME MEASURES: Diagnosis elicited by present state examination, global social disability rating, use of services during the three months before interview. RESULTS: 89 of the 140 patients (64%) had been ill for five or more years, yet few were former long stay inpatients. 55% (50/91; 95% confidence interval 45% to 65%) of those interviewed had current psychotic mental states and 22% (27/124; 16% to 31%) were functioning socially at very poor or severely maladjusted levels. 86% (107/124) were unemployed. The majority of patients had seen a mental health or social service professional, yet only 16% (20/124) were in specialised accomodation (excluding hospitals) and only 23% (17/73) of those eligible had used day care. Small numbers of people had experienced homelessness (two) or imprisonment (four over six months). CONCLUSIONS: Many schizophrenic patients leaving local psychiatric inpatient care have active symptomatology and profound social disabilities. Community care was characterised by high rates of contact with service professionals but little supported accommodation or day activity. This group of clients may require dedicated provision, which would actively encourage them to use services protected from the demands of those with less severe illness.