Comparison of manual and automatic segmentation methods for brain structures in the presence of space-occupying lesions: a multi-expert study.

The purpose of this work was to characterize expert variation in segmentation of intracranial structures pertinent to radiation therapy, and to assess a registration-driven atlas-based segmentation algorithm in that context. Eight experts were recruited to segment the brainstem, optic chiasm, optic nerves, and eyes, of 20 patients who underwent therapy for large space-occupying tumors. Performance variability was assessed through three geometric measures: volume, Dice similarity coefficient, and Euclidean distance. In addition, two simulated ground truth segmentations were calculated via the simultaneous truth and performance level estimation algorithm and a novel application of probability maps. The experts and automatic system were found to generate structures of similar volume, though the experts exhibited higher variation with respect to tubular structures. No difference was found between the mean Dice similarity coefficient (DSC) of the automatic and expert delineations as a group at a 5% significance level over all cases and organs. The larger structures of the brainstem and eyes exhibited mean DSC of approximately 0.8-0.9, whereas the tubular chiasm and nerves were lower, approximately 0.4-0.5. Similarly low DSCs have been reported previously without the context of several experts and patient volumes. This study, however, provides evidence that experts are similarly challenged. The average maximum distances (maximum inside, maximum outside) from a simulated ground truth ranged from (-4.3, +5.4) mm for the automatic system to (-3.9, +7.5) mm for the experts considered as a group. Over all the structures in a rank of true positive rates at a 2 mm threshold from the simulated ground truth, the automatic system ranked second of the nine raters. This work underscores the need for large scale studies utilizing statistically robust numbers of patients and experts in evaluating quality of automatic algorithms.

Policy reform dilemmas in promoting employment of persons with severe mental illness.

Recent evaluations by the U.S. General Accounting Office and the National Alliance for the Mentally Ill of reemployment efforts of the federal-state vocational rehabilitation program found that services offered by state vocational rehabilitation agencies do not produce long-term earnings for clients with emotional or physical disabilities. This paper examines reasons for these poor outcomes and the implications of recent policy reform recommendations. Congress must decide whether to take action at the federal level to upgrade programs affecting persons with severe mental illnesses or to continue to rely on state decision making. The federal-state program largely wastes an estimated $490 million annually on time-limited services to consumers with mental illnesses. Rechanneled into a variety of innovative and more appropriate integrated services models, the money could buy stable annual vocational rehabilitation funding for 62,000 to 90,000 consumers with severe mental illnesses. Larger macrosystem problems involve the dynamics of the labor market that limit job opportunities and the powerful work disincentives for consumers with severe disabilities now inherent in Social Security Disability Insurance, Supplemental Security Income, Medicare, and Medicaid.

Recovery of staphylococcal enterotoxin F from the breast milk of a woman with toxic-shock syndrome.

At 22 hr after an uncomplicated delivery of a healthy full-term infant, a 26-year-old woman developed toxic-shock syndrome (TSS). A vaginal culture yielded a coagulase-positive Staphylococcus that produced staphylococcal enterotoxin F (SEF) but no other enterotoxins. Breast milk specimens obtained on postpartum days 5, 8, and 11 contained 3.0, 2.5, and 2.0 ng of SEF/ml, respectively. Sera obtained from the mother on postpartum days 4 and 38 had titers (by radioimmunoassay) of antibody to SEF of 1:5 and less than 1:5, a result demonstrating a persisting lack of antibody to SEF after the first episode of TSS; the infant's serum titer of antibody to SEF on day 38 was also less than 1:5. Further longitudinal monitoring of SEF and antibody to SEF in breast milk from this patient is presented. This case is the first isolation of SEF from a body fluid obtained from a patient with TSS further strengthens the association between SEF and TSS.

Rehabilitating the severely disabled: the foreign experience.

This paper sets forth a model for examining the relationships between fourteen policy and politicoeconomic variables, and the social benefits and costs of rehabilitation. Based on discussions in early 1977 with scholars, ministry officials, trade unionists, and politicians in several northwestern European countries, as well as on documentation relating to the rapid growth of disability expenditures and the factors thought to influence it, some "lessons" are presented for policymakers in the United States and other countries. In general, current trends are seen as depressing the post-service earnings of individual rehabilitants, limiting the stabilizing effects of rehabilitation on labor market turnover, and increasing available time for unpaid work in the home and elsewhere. Unequal intergovernmental cost sharing in the provision of benefits and services, it is argued, seems likely to promote inefficient allocation of scarce rehabilitation resources with negative consequences for goal attainment. The high rates of inflation which prevail in the United States and in many northwestern European countries are causing the immediate costs of providing rehabilitation services to rise and simultaneously increasing the opportunity costs of spending for rehabilitation. The net effect of these cost increases is a reduction in the overall benefit/cost ratio that results from investments in rehabilitation. A number of predictions are made about how the United States will shape its disability and rehabilitation policies in the course of the next twenty years.