11 research outputs found

    Smart Flow for the evaluation of the hemodialysis arteriovenous fistula

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    Background: Smart Flow is an innovative tool available on the Carestream Touch Prime Ultrasound machines, which provides automated blood flow measurement and shows the vectors that form the blood flow in the vessel. We compared the use of Smart Flow with traditional Duplex Doppler Ultrasound to evaluate blood flow of arteriovenous fistulas in prevalent hemodialysis patients. Methods: A total of 31 chronic patients on hemodialysis were enrolled. Blood flow was measured on the brachial artery with Smart Flow and duplex Doppler ultrasound. In a subset of 26 patients, a video of the juxta-anastomotic efferent vein was recorded and analyzed to calculate an index of flow turbulence. Results: We enrolled 21 males and 10 females aged 68.52 ± 11.64 years at the time of evaluation with an average arteriovenous fistulas vintage of 50.23 ± 47.42 months and followed them up for 18.03 ± 5.18 months. Smart Flow and Duplex Doppler Ultrasound blood flow measurements positively correlated (p < 0.0001) in the same patient but Smart Flow gave higher blood flow values (995.0 vs 730.3 mL/min, p < 0.0001), and the Duplex Doppler Ultrasound blood flow standard deviation was similar to Smart Flow (125.4 vs 114.4 mL/min, p < 0.0001). The time needed to evaluate arteriovenous fistulas with Smart Flow was significantly shorter than Duplex Doppler Ultrasound (67.58 ± 19.89 vs 146.3 ± 26.35 s, p < 0.0001). No correlation was found between blood flow turbulence and the subsequent access failure. Conclusion: Smart Flow is reliable, reproducible, and faster than traditional duplex ultrasound. However, the additional information given by the Smart Flow technique does not seem to add any further benefits in terms of prediction of the access failure

    Vivid visual mental imagery in the absence of the primary visual cortex

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    The role of the primary visual cortex in visual mental imagery has provided significant debate in the imagery literature. Functional neuroimaging studies show considerable variation depending on task and technique. Patient studies can be difficult to interpret due to the diverse nature of cortical damage. The type of cortical damage in patient SBR is exceedingly rare as it is restricted to the gray matter of the calcarine sulcus. In this study, we show that in spite of his near-complete cortical blindness, SBR exhibits vivid visual mental imagery both behaviorally and when measured with functional magnetic resonance imaging. The pattern of cortical activation to visual mental imagery in SBR is indistinguishable from individual sighted subjects, in contrast to the visual perceptual responses, which are greatly attenuated

    Crossed Aphasia. I: A Case-Study with Purely Deep Lesion

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    In this paper, we describe the case of a right-handed man, MR, who after right thalamic haemorrhage presented subtranscortical aphasia. Of the disturbances generally associated with standard left hemisphere functions, the patient presented acalculia but not apraxia. Among the functions attributed to the standard right hemisphere, MR showed impairment in affective language and presented unilateral neglect and a strong position preference

    Generating Visual Mental Images - Deficit After Brain-damage

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    This is the first non-retrospective neuropsychological group study using a componential task analysis for the study of imagery. Seventy unilaterally brain damaged patients were tested on a series of tasks with the intent of isolating genuine deficits of the image generation process. The main finding is that the image generation seems to be more frequently disturbed after a left posterior damage. Suggestions are provided for further investigations
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