Minimizing the Long-term Effects of Ionizing Radiation in Pediatric Computed Tomography Examinations.

PURPOSE: To identify methods for minimizing the effects of ionizing radiation from pediatric computed tomography (CT) examinations, including the education of medical staff, imaging staff, and patients, and dose-reduction techniques that provide the best patient care and highest image quality at the lowest possible dose. METHODS: A literature search was conducted for peer-reviewed journal articles and Web-based information from professional organizations that discuss ionizing radiation in CT examinations and its effects on adult or pediatric patients. RESULTS AND DISCUSSION: The literature indicates that dose-reduction methods, such as using appropriate technical factors and shielding, are beneficial in acquiring the best image quality for proper diagnosis at the lowest dose possible to the patient. In addition, a radiologist review of examination requisitions can help eliminate duplicate orders and unnecessary examinations, along with providing recommendations for alternative examinations that do not use radiation such as ultrasonography and magnetic resonance imaging. Education for referring physicians and other medical professionals on the importance of alternative examinations and dose-reduction methods is essential to ensure they provide adequate education to pediatric patients and their families. CONCLUSION: Patient education and radiation safety are top priorities for imaging professionals. Radiation exposure to pediatric patients should be minimized through the use of shielding, appropriate CT parameters, other dose-reduction methods, and education. Further research is needed in these areas to ensure optimal patient care.

Evidence that better outcome of psychosis in women is reversed with increasing age of onset: a population-based 5-year follow-up study.

BACKGROUND: Female gender and later onset of psychosis are both associated with better outcome. However whether their effects are independent, is not known. METHOD: In 379 incident cases of psychoses, from an epidemiologically defined catchment area, admixture analysis was employed to generate age of onset classes. Five year course and outcome measured across clinical and social domains were used as dependent variables in regression analyses, to estimate associations of outcomes with gender, age of onset and gender by age of onset interaction. RESULTS: Three age of onset classes were identified: early (14-41 years), late (42-64 years) and very late onset psychosis (65-94 years). Overall, women had better outcomes, including milder delusions, fewer negative symptoms, less deterioration from baseline functioning, fewer hospital readmissions and shorter psychotic episodes. Later age of onset was also associated with better outcome, although in the very late onset class the results were mixed. There was a statistically significant gender by age of onset interaction (in the ratio scale) within this sample with men displaying poorer outcome in the early/late onset class, whereas women tended to have a worse outcome in the very late onset class. CONCLUSIONS: The favourable outcome in women becomes reversed in old age, suggesting gender-age-related differences in the distribution of aetiological factors for psychosis.

Do symptom dimensions or categorical diagnoses best discriminate between known risk factors for psychosis?

OBJECTIVE: To describe symptom dimensions of psychosis using detailed psychopathological information from epidemiologically defined incident cases which include the full spectrum of functional psychosis across all age ranges. Then, assess the comparative usefulness of the dimensional and categorical representations of psychosis in discriminating between demographic and pre-morbid risk factors. METHOD: A total of 464 incident cases of psychosis assessed with OPCRIT (Operational Checklist for Psychotic Symptoms) were included in an exploratory factor analysis. Using Regression analyses we modelled the associations of the dimensional and categorical representations of psychosis with antecedent validating variables and compared the subsequent models using the likelihood ratio test. RESULTS: Factor analysis produced five-symptom dimensions, manic, disorganisation, depressive, delusional and auditory hallucinatory symptoms, explaining 58% of the total variance. Different dimensions were differentially associated with the pre-morbid risk factors. Neither the dimensional nor the categorical representations on their own were sufficient to explain associations with the antecedent validating variables. CONCLUSION: Neither the dimensional or the diagnostic representation of psychosis was superior in discriminating between known risk factors, combining dimensional measures with categorical diagnoses will probably be more informative in determining the causes and correlates of psychosis.

Long-term course of cognitive impairment in schizophrenia.

The aim of this study was to examine the long-term course of cognitive impairment in people with schizophrenia. Forty-three people with schizophrenia were followed up over an average of 33 years along with a control group of 12 matched individuals free from psychosis. Cognitive function was assessed at baseline and follow-up. The participants with schizophrenia were found to show impairment in verbal and non-verbal intelligence at baseline compared with estimated premorbid scores, this was not found in the control group. At follow-up there was a significant decline in non-verbal intelligence over time in participants with schizophrenia compared with controls (P=0.007). This differential change over time was not seen in verbal intelligence (P= 0.318).

Summer birth and deficit schizophrenia in Dumfries and Galloway, southwestern Scotland.

OBJECTIVE: An association between deficit schizophrenia and summer birth has previously been reported. Confirmation of a separate risk factor for this group of patients is potentially important, but the number of subjects with deficit schizophrenia in previous reports has been small. This analysis used data from an epidemiological study of incident cases of psychosis to test the hypothesis that deficit schizophrenia is associated with summer birth. METHOD: Data were drawn from records for the first year of clinical contact for all new patients coming into treatment for psychosis in the region of Dumfries and Galloway, Scotland, from 1979 to 1998. Patients with schizophrenia were classified as having deficit (N=65) or nondeficit (N=277) schizophrenia. Time of birth in the deficit and nondeficit groups was compared, and time of birth in the deficit group was compared with that for all births in Dumfries and Galloway during the study period. RESULTS: The deficit schizophrenia group had an excess of summer births, compared to both the nondeficit schizophrenia group and all births in Dumfries and Galloway. The difference between the deficit and nondeficit schizophrenia groups remained significant after accounting for demographic characteristics and symptoms of disorganization and hallucinations plus delusions. A measure of negative symptoms (as opposed to deficit schizophrenia) was a weaker predictor of summer birth. CONCLUSIONS: This study confirmed an association between deficit schizophrenia and summer birth in the nontropical regions of the Northern Hemisphere. The existence of a risk factor for deficit but not nondeficit schizophrenia is also consistent with other evidence that the pathophysiology of deficit schizophrenia differs from that for other types of the disorder.