Biomedical sciences instrumentation
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This study introduces a 3-D segmentation method together with a graphical user interface (GUI) as means to effectively automate the process of segmentation with the ultimate objective of integrating and visualizing diffusion tensor imaging (DTI) with magnetic resonance imaging (MRI) in a fully automated 3-D brain imaging system. A secondary objective is to reduce significantly the segmentation time required to extract key landmarks of the brain in contrast to the manual process currently used at many hospital settings. The results provided will prove this important assertion. ⋯ The average speed of segmentation was just 35 seconds, a reduction of over 20 times of what is required for manual segmentation. In order to create a highly integrated interface, the segmentation results serve as input to a registration algorithm we are currently investigating and whose preliminary results support the significance of relying on an effective segmentation process. T1-weighted 3D Gradient Echo MR and DT images from 16 patients at Miami Children's Hospital were used for evaluation purposes.
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Translational and rotational accelerations from blunt head impact can induce excessive brain strain and cause traumatic brain injuries. However, it is not clear which acceleration plays a major role in the mechanism. ⋯ Results indicated that rotational acceleration contributes more than 90% of total strain, and translational acceleration produces minimal strain. Therefore, the rotational component is a more important biomechanical metric in this study.
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Clinical Trial
Reliability of respiratory tidal volume estimation by means of ambulatory inductive plethysmography.
Ambulatory monitoring of ventilatory parameters in everyday life, field research and clinical situations may offer new insights into respiratory functioning in health and disease. Recent technological advances that employ ambulatory inductive plethysmography could make monitoring of respiration outside the clinic and laboratory feasible. Inductive plethysmography provides a method for nonintrusive assessment of both timing (e.g. respiration rate) and volumetric parameters (e.g. tidal volume and minute ventilation), by which tidal volume is initially calibrated to direct measures of volume. ⋯ Furthermore, reliability estimates were high and consistent across respiratory measures (typically r's = 0.7-0.8). These results suggest the validity of ambulatory inductive plethysmographic measurement of respiration, at least under relatively sedentary conditions. Findings also point to the stability of individual differences in respiratory parameters over consecutive weeks.
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The purpose of this study is to develop injury risk functions that predict zygoma fracture based on baseball type and impact velocity. Zygoma fracture strength data from published experiments were mapped with the force exerted by a baseball on the orbit as a function of ball velocity. Using a normal distribution, zygoma fracture risk functions were developed. ⋯ The experimental results validated the zygoma risk functions at the lower and upper levels. The injuries observed in the post test analysis included fractures of the zygomatic arch, frontal process and the maxilla, zygoma suture, with combinations of these creating comminuted, tripod fractures of the zygoma. Tests with a softer baseball did result in injury but these had fewer resulting zygoma bone fragments and occurred at velocities 50% higher than the major league ball.
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Facial bone fractures in the military can result from direct loading of night vision goggles on the orbital region. Facial fracture research has shown that increasing the area over which the load is applied increases the load tolerance. The purpose of this study is to apply this concept to reducing the risk of facial bone fracture from night vision goggle impacts. ⋯ Two impacts to the male subject with a custom face shield resulted in peak loads of 4554 N and 5101 N with no injury. The final impact to the male subject had a peak load of 2010 N with complete orbital fracture due to the absence of a countermeasure. From these tests it is shown that facial fracture risk from night vision goggle impact can be reduced using a contoured rigid face shield.