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Intracranial circulation: pulse-sequence considerations in three- dimensional (volume) MR angiography 总被引:2,自引:0,他引:2
The technique and feasibility of magnetic resonance (MR) angiography of intracranial vessels were studied in 35 healthy volunteers. Variations in image orientation, repetition time (TR), and flip angle were evaluated to determine their effects on flow-related enhancement. Gradient modifications--including echo time (TE), motion compensation, bandwidth, and field of view--were also studied in an effort to reduce motion-induced phase shifts. Results indicated that a FISP (fast imaging with steady precession) sequence with a TR of 50 msec, TE of 15 msec, velocity compensation in the read and section-select directions, acceleration compensation in the read direction, anisotropic volume, and a 1.25-mm partition thickness produced three-dimensional angiographic MR images that were accurate and reproducible in the depiction of the major intracranial vessels. Difficulties with field of view, persistent signal void secondary to higher-order motion, and spatial resolution remain major problems requiring additional study. 相似文献
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Denis Nissim-Sabat William H. Farr Kathleen McCune Melanie Stith 《Community mental health journal》1986,22(2):160-165
This study represents the first of a two-stage project. The first phase of the study examined the funding sources for the 40 Community Services Boards in Virginia. Data provided from the Department of Mental Health and Mental Retardation in Virginia examined fee collections which are comprised of direct client, commercial insurance, Medicaid and Medicare. An analysis of quarterly reports from 1982 to 1984 revealed that Medicaid collections have decreased significantly, while commercial insurance reimbursements have increased significantly. These results, although limited to data from Virginia, point to the need to examine if these shifts are occurring nation-wide, and to determine if the shift toward commercial insurance is impacting upon the delivery of services in Community Mental Health Centers. 相似文献
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Ralls PW; Johnson MB; Kanel G; Dobalian DM; Colletti PM; Boswell WD Jr; Radin DR; Halls JM 《Radiology》1986,161(2):451-454
FM sonography - a signal-processing technique that uses frequency and phase information as well as amplitude data - shows promise in evaluation of patients with diffuse liver disease. In a prospective blinded review of 37 patients with biopsy-proved liver disease and 42 healthy volunteers, FM sonography was clearly superior to traditional amplitude-based (AM) sonography in distinguishing healthy from diseased subjects. Statistically significant differences were seen in accuracy (FM, 98.7%; AM, 84.8%), sensitivity (FM, 97.3%; AM, 70.3%), and negative predictive value (FM, 97.7%; AM, 78.8%). Our data also suggest that current FM sonographic techniques cannot differentiate among histologic findings associated with different hepatic parenchymal abnormalities. It is unclear, therefore, whether FM imaging can reduce the numbers of patients who require biopsy for diagnosis or the frequency of biopsy procedures in patients with known disease. 相似文献
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Objective . To describe the importance of migraine in Santiago, Chile, by analyzing its prevalence, clinical features and impact by age, gender and socioeconomic status. Methods . In 1993, a representative sample of 1,540 adults of the province of Santiago were interviewed using a standard questionnaire. A total of 1,385 (89.9%) subjects responded to the survey. Initially, a designated member of each household responded to the questionnaire. Subsequently, each household member with headaches was asked to respond to questions about severity, frequency, location, duration, associated symptoms and impact in work and social activities of their most frequent headaches. Migraine diagnoses were determined in accordance with the International Headache Society (IHS) criteria of 1988. Results. Recurrent headaches in the past year were found in 516 (36.82%) respondents, 145 (28.1%) males and 371 (71.9%) females. Total prevalence of migraine was found to be 7.3% (95%, CI 5.9–8.6); 11.9% (95% CI 9.6–14.2) in females and 2.0% (95% CI 0.9–3.0) in males. Overall, migraine constituted 19.6% (101/516) of all headaches reported in this sample. The prevalence did not vary significantly by age groups or socioeconomic status (SES). Migraine with aura had an overall prevalence of 3.5% (CI 0.8–7.1), and was significantly more frequent in females. In 60–70% of cases the attacks lasted 2–6 h and the frequency was 3.3 and 3.4 per month in females and males respectively. Both males and females reported significantly high percentages of attacks during work. Conclusions . Migraine prevalence in a sample of adults of Santiago is similar to that reported in previous studies using IHS criteria. Women of all socioeconomic levels are at an increased risk. 相似文献
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Contraceptive efficacy of the Copper T380A and the Multiload Cu250 IUD in three developing countries
The clinical performance of the Copper T380A (TCu380A) and the Multiload 250 (MLCu250) intrauterine devices (IUDs) were evaluated for 12 months in a group of women who had one of the two IUDs inserted. Results are from a randomized clinical trial conducted at four collaborating research sites located in three developing countries.The gross cumulative life-table pregnancy rate of the TCu380A IUD was significantly lower than the rate with the MLCu250 IUD at 12 months (0.5 and 1.2, respectively,p<0.01). No statistically significant differences between the two study IUDs were found with regard to IUD expulsion or IUD removal due to bleeding/pain, personal reasons, medical reasons, or planned pregnancy. TCu380A IUD users were more likely to report experiencing increased dysmenorrhea (p<0.01) or intermenstrual pelvic pain (p<0.01) than were MLCu250 IUD users. However, few of these users discontinued use of their assigned IUD because of having experienced menstrual bleeding disturbances or intermenstrual pelvic pain.These data indicate that the TCu380A IUD may be a better option than the MLCu250 IUD for women wishing to practice highly effective long-term birth control without having to resort to hormonal methods.
Resumen El resultado clínico de los dispositivos intrauterinos (DIU) Copper T380A y Multiload 250 (MLCu250) se evaluó durante 12 meses en un grupo de mujeres a quienes se había colocado uno de los dos DIU. Los resultados corresponden a un ensayo clínico aleatorizado efectuado en cuatro emplazamientos de investigaciones en colaboración situados en tres países en desarrollo.La tasa bruta acumulativa de embarazo de las tablas de vida del DIU TCu380A fue significativamente inferior a la tasa correspondiente al DIU MLCu250 a los 12 meses (0,5 y 1,2, respectivamente,p<0,01)). No hubo diferencias estadísticamente significativas entre los dos DIU del estudio con respecto a su expulsión o retiro debido a microrragia/dolor, razones personales, razones médicas o embarazo planificado. Era más probable que las usuarias del DIU TCu380A notificaran mayor dismenorrea (p<0,01) o dolor pélvico intermenstrual (p<0,01) que las usuarias del DIU MLCu250. Sin embargo, un número menor de este grupo de usuarias dejó de utilizar el DIU que le había sido asignado por haber experimentado trastornos menstruales de microrragia o dolor pélvico intermenstrual.Estos datos indican que el DIU TCu380A podría ser una mejor opción que el DIU MLCu250 para las mujeres que desean praticar un control de la natalidad a largo plaza altamente eficaz sin tener que recurrir a métodos hormonales.
Resumé Les résultats cliniques des dispositifs intra-utériens (DIU) Copper T38OA (TCu380A) et Multiload 250 (MLCu250) ont été évalués pendant 12 mois chez un groupe de femmes qui portaient l'un ou l'autre de ces dispositifs. Les résultats proviennent d'un essai clinique randomisé, effectué en collaboration par quatre établissements de recherche dans trois pays en développement.Au terme de 12 mois, le taux brut cumulé de grossesses des tables de survie pour le dispositif TCu380A était significativement inférieur au taux correspondant pour le dispositif MLCu250 (0,5 et 1,2 respectivement,p<0,01). Aucune différence statistiquement significative entre les deux dispositifs étudiés n'a été constatée du point de vue de l'expulsion du DIU ou de son retrait pour cause de microrragie/douleurs, pour des raisons personnelles ou médicales ou pour une grossesse planifiée. Les utilisatrices du TCu380A ont plus fréquemment signalé une dysménorrhée (p<0,01) ou des douleurs pelviennes intermenstruelles (p<0,01) que les utilisatrices du MLCu250. Peu nombreuses était cependant cells qui avaient, en raison de perturbations du flux menstruel ou de douleurs pelviennes intermenstruelles, abandonné l'usage du dispositif qui leur avait été assigné.Ces résultats indiquent que le dispositif TCu380A représente peut-être une meilleure solution que le dispositif MLCu250 pour les femmes recherchant à long terme une méthode hautement efficace de régulation des naissances, sans avoir recours aux méthodes hormonales.相似文献
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