Respiratory motion prediction by using the adaptive neuro fuzzy inference system (ANFIS)

The quality of radiation therapy delivered for treating cancer patients is related to set-up errors and organ motion. Due to the margins needed to ensure adequate target coverage, many breast cancer patients have been shown to develop late side effects such as pneumonitis and cardiac damage. Breathing-adapted radiation therapy offers the potential for precise radiation dose delivery to a moving target and thereby reduces the side effects substantially. However, the basic requirement for breathing-adapted radiation therapy is to track and predict the target as precisely as possible. Recent studies have addressed the problem of organ motion prediction by using different methods including artificial neural network and model based approaches. In this study, we propose to use a hybrid intelligent system called ANFIS (the adaptive neuro fuzzy inference system) for predicting respiratory motion in breast cancer patients. In ANFIS, we combine both the learning capabilities of a neural network and reasoning capabilities of fuzzy logic in order to give enhanced prediction capabilities, as compared to using a single methodology alone. After training ANFIS and checking for prediction accuracy on 11 breast cancer patients, it was found that the RMSE (root-mean-square error) can be reduced to sub-millimetre accuracy over a period of 20 s provided the patient is assisted with coaching. The average RMSE for the un-coached patients was 35% of the respiratory amplitude and for the coached patients 6% of the respiratory amplitude.     

Long-term effect of intravenous thrombolytic therapy in acute stroke: responder analysis versus uniform analysis of excellent outcome

BACKGROUND: Knowledge regarding functional improvement over time and long-term outcome after intravenous thrombolysis in acute ischaemic stroke is limited. The aim of this study was to compare a uniform assessment of outcome with an assessment taking the baseline stroke severity into account (responder analysis). METHODS: Fifty-seven patients were assessed with the modified Rankin Scale at 3, 6 and 12 months and a comparison was made between a uniform assessment and a responder analysis of excellent outcome. RESULTS: Between 3 and 12 months, 74% of the patients had a stable functional outcome and 22% improved. Excellent outcome at 12 months was similar in the uniform analysis (37%) and the responder analysis (35%). The individual patients having an excellent outcome differed, however, using the two methods. Using a responder analysis the number of patients with excellent outcome decreased in mild stroke patients by 40%, but increased in severe stroke patients by 43%. CONCLUSIONS: Short-term outcome is sustained at 12 months, but major improvement does not occur between 3 and 12 months. A responder analysis of long-term excellent outcome provided a balanced measure of outcome reflecting the drug-related potential of improvement in all stroke severity subgroups, whereas a uniform analysis provided a measure of outcome mainly in mild stroke patients. These results suggest that a responder analysis should be considered for the assessment of outcome after treatment for acute stroke.     

Cesarean section: is pretransfusion testing for red cell alloantibodies necessary?

BACKGROUND: Routine pretransfusion testing for red cell alloantibodies (RBCab) in cesarean patients is standard practice in many obstetric centers. The objective of the present study was to evaluate the usefulness of this test. METHOD: A retrospective study was conducted using computerized registers to extract data on blood transfusions and the occurrence of RBCab in cesarean patients. RESULTS: A total of 4434 admissions for cesarean section were identified. Only 10 patients (0.23%) had clinically significant RBCab, which had not been previously detected. Blood transfusions were required in relation to 147 cesarean sections (3.3%). A number of preoperative conditions, traditionally believed to be risk factors for preoperative and postpartum hemorrhage, occurred more frequently in transfused patients than in nontransfused. The probability of a cesarean patient having a previously undetected clinically significant RBCab and receiving a blood transfusion during admission for delivery was estimated to be 9.0 x 10(-5) (1 in 11 050 cesarean sections). Analyses of the time relationships between cesarean sections and initiation of blood transfusions indicated that most often there would be enough time for postoperative antibody screening and/or cross matching if the routine pretransfusion testing was omitted. CONCLUSION: These findings suggest that routine pretransfusion testing in cesarean patients can be omitted.     

Intraoperative and intermediate-term angiographic results of coronary artery bypass surgery with Symmetry proximal anastomotic device

OBJECTIVE: The objective of this study was to investigate the patency in saphenous vein coronary bypass grafts in which the proximal anastomoses were performed with automatic connector devices or with a traditional suture technique. METHODS: Forty-six patients underwent coronary artery bypass grafting without cardiopulmonary bypass by using one thoracic graft and one or more saphenous vein grafts. Grafts were attached to the aorta with a Symmetry connector (St Jude Medical, Inc, St Paul, Minn) in 23 patients, and partial occlusion of the aorta and sutured anastomoses were used in 23 other patients. Grafts were studied intraoperatively with transit time flowmetry and angiography and revised if necessary. Angiography was repeated after 3 to 5 months. RESULTS: Intraoperative graft patency did not differ between the 2 groups. Follow-up angiography demonstrated excellent thoracic graft patency. Vein graft patency decreased to 50% in the Symmetry group, whereas it was 90% in the suture group ( P = .01). Twenty-five percent of the Symmetry grafts had significant stenosis in the connector. CONCLUSION: Saphenous vein grafts anastomosed to aorta with the Symmetry proximal connector have low intermediate patency compared with those with traditionally sutured anastomoses. We do not recommend the routine use of this device in coronary artery bypass operations.     

Prediction of fusion and importance of radiological variables for the outcome of anterior cervical decompression and fusion

In a prospective randomised study with a 2-year follow-up, 103 patients were randomised to anterior cervical decompression and fusion (ACDF) with a cervical carbon-fibre intervertebral fusion cage (CIFC) or the Cloward procedure (CP). The purpose of the present study was to report predictors for fusion and also to investigate the importance of radiological variables for the clinical outcome. Gender, age, smoking habits, disc height, segmental kyphosis and type of surgical procedure were used as independent (before surgery) variables in a multiple regression model. Male gender, one-level surgery and CP treatment were significant predictors of fusion and explained 14% of the variability of fusion status at follow-up. Number of levels operated on, however, did not influence the clinical outcome. Fifty-two per cent of the women and 17% of the men in the CIFC group, and 25% of the women and 8% of the men in the CP group, had pseudarthrosis. Although patients with a healed fusion had significantly less pain intensity than patients with pseudarthrosis, radiological variables explained only 4% of the variability of pain at follow-up. Apart from a significant correlation between preoperative kyphosis and neck disability index at follow-up, no significant correlation between either postoperative kyphosis or preoperative or postoperative disc height and clinical outcome was found. Neither degree of segmental kyphosis nor disc height was different between patients with healed fusion and pseudarthrosis. One can conclude that male gender and type of surgery were significant predictors for a healed fusion and that pseudarthrosis affected outcome. In contrast to the commonly held view based mainly on theoretical considerations, no effect on clinical outcome could be demonstrated for segmental kyphosis and disc height at follow-up. Overall, the study shows that the importance of radiological factors as predictors for fusion as well as clinical outcome is limited.     

Feasibility of color doppler tissue velocity imaging for assessment of regional timing of left ventricular longitudinal movement

OBJECTIVE--The feasibility of color Doppler tissue velocity imaging (c-TVI) with a high time resolution of 10 ms for simultaneous measurement of the temporal characteristics of regional left ventricular (LV) tissue velocities at different LV sites was examined. Methods and results--In 20 subjects with structurally normal hearts, inter- and intraobserver agreement and the beat-to-beat variation were tested in c-TVI profiles from basal and mid-LV segments of the interventricular septum (IS) and of the lateral free wall (LFW). For peak tissue velocities a mean error of less than 1 cm/s was demonstrated. For systolic regional LV velocity time difference, the mean error was +/- 5 ms, with the best agreement when sampling from basal LV sites. For diastolic regional LV velocity time differences, the mean error was +/- 12 ms. The longitudinal LV movement pattern demonstrated a pattern of incremental tissue velocity from basal to mid-LV, and from IS to LFW sites. Conclusion--The c-TVI method has acceptable inter- and intraobserver agreement and is sufficiently accurate to disclose regional time aspects of LV contraction and relaxation.     

Median raphe mediates estrogenic effects to the hippocampus in female rats

Subcortical regions such as the medial septum-diagonal band of Broca and supramammillary area have been shown to mediate indirect oestrogenic effects on hippocampal morphology and function. Here, the role of the median raphe (MR), a serotonergic subcortical structure, is studied. To this end, 17beta-estradiol-filled 30-gauge cannulae were implanted into the MR of female ovariectomized rats; cholesterol-filled cannulae served as controls. After seven days, using unbiased electron microscopic stereological calculations and semiquantitative analysis, the spine synapse density and surface density of glial fibrillary acidic protein-positive astrocyte processes, respectively, were determined in the stratum radiatum of the CA1 region of the hippocampus. Changes in the serotonergic innervation of the hippocampal CA1 region were determined by immunohistochemistry and subsequent morphometric analysis. In the stratum radiatum of the CA1 region, local estradiol application into the MR resulted in a 47% increase in spine synapse density. Simultaneously, the density of glial fibrillary acidic protein-positive fibers decreased by 16%. The density of serotonin (5-HT) innervation of the strata lacunosum moleculare and radiatum of the CA1 region of the hippocampus was reduced in response to estradiol, as shown by a decrease in the length of fibers (27.6 and 48.3% decrease, respectively) and the number of large varicosities (32.5 and 38.8% decrease, respectively). These observations suggest a major role of the MR in mediating oestrogenic effects on the hippocampus and an involvement of the serotonergic system.