Brain activation during silent word generation evaluated with functional MRI.

This is a study of word generation during functional MRI (fMRI). Eleven normal healthy subjects were instructed to generate words covertly, (i.e., silently) that began with particular letters. Images were acquired on a conventional 1.5T scanner at three contiguous axial planes encompassing language-related areas of the temporal and frontal lobe. The data were analyzed at the level of a Talairach box, after individually fitting the proportional Talairach grid system to each slice. The main variable of interest was the number of activated pixels within a Talairach box. Boxes with a significant increase in the proportion of activated pixels were located in three regions of the left neocortex: (1) Brodmann areas 44 and 45 in the dorsolateral frontal cortex (Broca's area), (2) areas 21 and 37 in the temporal cortex, (3) and the striate/extrastriate cortex (areas 17 & 18). The results are discussed in terms of a cognitive model of word generation and are compared, in detail, with the results of prior relevant imaging studies.

Interactive MR imaging-guided biopsy and aspiration with a modified clinical C-arm system.

OBJECTIVE: This investigation was performed to test the hypotheses that interactive guidance of MR image acquisition during needle-directed procedures using a clinical 0.2-T C-arm open MR imaging system integrated with a frameless optically linked stereotaxy system is feasible, and that procedure times can be sufficiently short to be well tolerated by the patient. SUBJECTS AND METHODS: One hundred six MR-guided procedures were performed in 86 patients (ranging in age from 5 months to 88 years) using a clinical C-arm imaging system supplemented with an in-room RF-shielded liquid crystal display monitor, a frameless stereotaxy system, rapid gradient-echo sequences for needle guidance, and MR-compatible monitoring and surgical lighting equipment. We performed 50 biopsies and aspirations of the head and neck in 37 patients, 23 biopsies of musculoskeletal lesions in 22 patients, 16 biopsies of abdominal sites in 10 patients, six biopsies of the thoracolumbar spine or sacrum in six patients, and 11 shoulder joint injections for MR arthrography in 11 patients, in addition to 38 MR arthrographic injections on the same imaging system described in a previous report. Tissue sampling included fine-needle aspiration (n = 90) and cutting needle core biopsy (n = 41). Thirty-five patients underwent both procedures. Procedures were evaluated for success of needle placement, procedure time, and complications. RESULTS: Needle placement was successful in all cases, and no complications occurred. Tissue was sufficient for pathologic diagnosis for all but eight patients. Passes per patient averaged 2.1. For fine-needle aspiration, instrument time averaged 7 min 42 sec per pass, cutting needle core biopsy averaged 6 min 24 sec, and shoulder injection averaged 8 min. CONCLUSION: MR imaging guidance for needle procedures on a clinical 0.2-T C-arm system with supplemental interventional accessories is feasible, with relatively rapid needle placement.

Treatment and outcomes in adolescents with schizophrenia.

The pharmacologic treatment and assessment of outcomes in adolescents with schizophrenia have been inadequately addressed. Structural brain imaging and brain function studies both point to a continuity between adolescent and adult stages of schizophrenia. Because the teenage population seems to be less tolerant of physical side effects, the advent of atypical antipsychotic medications may offer increased safety and efficacy. Studies support the notion that adolescent illness is associated with a more severe form of schizophrenia and that length of illness before treatment is correlated with long-term outcome. As a consequence, the authors recommend assertive pharmacologic intervention in adolescents with schizophrenia and future research focused on the issues of treatment and outcome in teenagers suffering a psychotic disorder.

Cortical localization of human sustained attention: detection with functional MR using a visual vigilance paradigm.

PURPOSE: Our goal was to determine whether functional MRI on a standard 1.5 T system can localize activation during a visual vigilance sustained attention task and whether this corresponds to results described in a PET investigation of a similar task. METHOD: Sixteen volunteers were studied on a 1.5 T system using a gradient echo technique. A single axial section was oriented within a stereotaxic coordinate space, 40 mm superior to the anterior-posterior commissure line. Images with eyes closed were followed by images during subject concentration on a small dim spot. Motion correction and pixel-by-pixel statistical analysis were performed. Talairach grids were applied for summary statistical analysis and comparison to PET data, with analysis using a series of planned contrasts within a repeated measures analysis of variance. RESULTS: Predominantly right-sided frontal and parietal activation was observed, with statistical significance across subjects in the right frontal lobe (F > or = 5.9, p < or = 0.041). Comparison with previously reported PET data yielded a very similar pattern of activation (F = 13.2; df = 1,8; p = 0.007). CONCLUSION: Activation of the right middle frontal gyrus and right parietal lobe during visual vigilance is detectable across functional imaging modalities.

Training for rural general practice.

OBJECTIVE: To identify requirements for vocational training and continuing education programs in rural general practice. DESIGN: A questionnaire was sent to all 487 rural doctors and 140 metropolitan and 140 provincial city general practitioners (GPs) in Queensland. A sample of medical educators, health professional and consumer representatives and rural doctors was also interviewed. Responses were compared by geographical area, practice characteristics and level of postgraduate training. RESULTS: There are significant differences between rural and urban practice profiles. Rural doctors have to practise a range of clinical skills in an environment with restricted access to health professional support, although the need for advanced training in procedural or other skills depends on the type of rural practice. Rural and urban doctors want more influence in determining continuing medical education (CME) programs. Interactive learning methods were rated as the most effective education methods by both rural and urban GPs. Rural doctors were less likely to consider that they spent enough time on CME. CONCLUSION: Vocational training programs should accommodate various rural career objectives, including those requiring advanced levels of procedural work. There is a significant unmet demand for CME tailored to the needs of individual doctors, both rural and urban, but distance and isolation may make this more critical in rural practice. These issues need to be addressed as training opportunities can contribute to improved retention of the rural medical workforce.

A sampling framework for rural and remote doctors.

A pilot survey by telephone interview, followed by a questionnaire of all rural doctors identified in Queensland, was used develop both a definition of rural practice that distinguishes it from urban general practice and a classification of rural and remote practice which assists in sampling of rural doctors. Questionnaire responses in specific geographic areas were compared using chi-square and Mantel-Haenszel chi-square tests. Several factors were found to differentiate rural from urban general practice consistently, thereby enabling a functional definition of rural practice to be developed. Within the broad group of rural doctors, gradients in practice characteristics were found to differentiate doctors in larger rural centres from those in smaller, more remote communities. These gradients were related to the distance and time of travel from support services. They formed the basis of a complex classification of rural and remote general practice. This functional definition of rural and remote medical practice should be considered by researchers of rural medicine issues when sampling rural and remote doctors. The strategies used in this study could be adapted for use in considering practice characteristics of other rural health professions.

Stability of diluted heparin sodium stored in plastic syringes.

The stability of heparin diluted in 0.9% sodium chloride injection and stored in plastic syringes for a three-week period was studied. Heparin activity was assayed by the activated partial thromboplastin time (APTT) method. Heparin sodium (25,000 units/ml) was diluted to 500 units/ml and stored in 50-ml polypropylene syringes. Concentrations were compared in two brands of syringes stored at room temperature in the dark. In another experiment controlled for order-related assay errors, heparin was stored in one brand by syringe at either 0-4 degrees C or room temperature. There was a statistically decrease in heparin activity over three weeks in both syringes and at both 0-4 degrees C and room temperature. However, the overall drop in activity was only about 8%. Analysis of covariance confirmed significant regression with time at both temperatures. An unexpected finding was that heparin at 500 units/ml consistently assayed higher than this value. A study of the effect of glass and plastic showed that when heparin was diluted into either a glass or plastic container, there was significantly less heparin activity in the glass containers within two hours. One possible explantation for this phenomenon is absorption of heparin to glass surfaces. It was concluded that heparin can be stored in polypropylene syringe for up to three weeks without refrigeration. However, once diluted, heparin should not be stored in glass containers.