Current Issue : July - September Volume : 2014 Issue Number : 3 Articles : 6 Articles
Background: Use of ultrasound in brain tumor surgery is common. The difference in attenuation between brain\nand isotonic saline may cause artifacts that degrade the ultrasound images, potentially affecting resection grades\nand safety. Our research group has developed an acoustic coupling fluid that attenuates ultrasound energy like the\nnormal brain. We aimed to test in animals if the newly developed acoustic coupling fluid may have harmful effects.\nMethods: Eight rats were included for intraparenchymal injection into the brain, and if no adverse reactions were\ndetected, 6 pigs were to be included with injection of the coupling fluid into the subarachnoid space. Animal\nbehavior, EEG registrations, histopathology and immunohistochemistry were used in assessment.\nResults: In total, 14 animals were included, 8 rats and 6 pigs. We did not detect any clinical adverse effects, seizure\nactivity on EEG or histopathological signs of tissue damage.\nConclusion: The novel acoustic coupling fluid intended for brain tumor surgery appears safe in rats and pigs under\nthe tested circumstances....
Background: Objective physical assessment of patients with lumbar spondylosis involves plain film radiographs\n(PFR) viewing and interpretation by the radiologists. Physiotherapists also routinely assess PFR within the scope\nof their practice. However, studies appraising the level of agreement of physiotherapistsââ?¬â?¢ PFR interpretation with\nradiologists are not common in Ghana.\nMethod: Forty-one (41) physiotherapists took part in the cross-sectional survey. An assessment guide was developed\nfrom findings of the interpretation of three PFR of patients with lumbar spondylosis by a radiologist. The three PFR were\nselected from a pool of different radiographs based on clarity, common visible pathological features, coverage body\nsegments and short post production period. Physiotherapists were required to view the same PFR after which they\nwere assessed with the assessment guide according to the number of features identified correctly or incorrectly. The\nscore range on the assessment form was 0ââ?¬â??24, interpreted as follow: 0ââ?¬â??8 points (low), 9ââ?¬â??16 points (moderate) and\n17ââ?¬â??24 points (high) levels of agreement. Data were analyzed using one sample t-test and fisherââ?¬â?¢s exact test at a = 0.05.\nResults: The mean score of interpretation for the physiotherapists was 12.7 Ã?± 2.6 points compared to the radiologistââ?¬â?¢s\ninterpretation of 24 points (assessment guide). The physiotherapistsââ?¬â?¢ levels were found to be significantly associated\nwith their academic qualification (p = 0.006) and sex (p = 0.001). However, their levels of agreement were not\nsignificantly associated with their age group (p = 0.098), work settings (p = 0.171), experience (p = 0.666), preferred PFR\nview (p = 0.088) and continuing education (p = 0.069).\nConclusions: The physiotherapistsââ?¬â?¢ skills fall short of expectation for interpreting PFR of patients with lumbar\nspondylosis. The levels of agreement with radiologistââ?¬â?¢s interpretation have no link with year of clinial practice,\nage, work settings and continuing education. Thus, routine PFR viewing techniques should be made a priority\nin physiotherapistsââ?¬â?¢ continuing professional education....
Background: Assessing heterogeneity in lung images can be an important diagnosis tool. We present a novel and\nobjective method for assessing lung damage in a rat model of emphysema. We combined a three-dimensional\n(3D) computer graphics methodââ?¬â??octree decompositionââ?¬â??with a geostatistics-based approach for assessing spatial\nrelationshipsââ?¬â??the variogramââ?¬â??to evaluate disease in 3D computed tomography (CT) image volumes.\nMethods: Male, Sprague-Dawley rats were dosed intratracheally with saline (control), or with elastase dissolved\nin saline to either the whole lung (for mild, global disease) or a single lobe (for severe, local disease). Gated 3D\nmicro-CT images were acquired on the lungs of all rats at end expiration. Images were masked, and octree\ndecomposition was performed on the images to reduce the lungs to homogeneous blocks of 2 Ã?â?? 2 Ã?â?? 2, 4 Ã?â?? 4 Ã?â?? 4,\nand 8 Ã?â?? 8 Ã?â?? 8 voxels. To focus on lung parenchyma, small blocks were ignored because they primarily defined\nboundaries and vascular features, and the spatial variance between all pairs of the 8 Ã?â?? 8 Ã?â?? 8 blocks was calculated\nas the square of the difference of signal intensity. Variogramsââ?¬â??graphs of distance vs. varianceââ?¬â??were constructed,\nand results of a least-squares-fit were compared. The robustness of the approach was tested on images prepared\nwith various filtering protocols. Statistical assessment of the similarity of the three control rats was made with a\nKruskal-Wallis rank sum test. A Mann-Whitney-Wilcoxon rank sum test was used to measure statistical distinction\nbetween individuals. For comparison with the variogram results, the coefficient of variation and the emphysema\nindex were also calculated for all rats.\nResults: Variogram analysis showed that the control rats were statistically indistinct (p = 0.12), but there were\nsignificant differences between control, mild global disease, and severe local disease groups (p < 0.0001). A\nheterogeneity index was calculated to describe the difference of an individual variogram from the control average.\nThis metric also showed clear separation between dose groups. The coefficient of variation and the emphysema\nindex, on the other hand, did not separate groups....
Background: Temperature measurement is a vital part of daily neonatal care. Accurate measurements are important for\ndetecting deviations from normal values for both optimal incubator and radiant warmer functioning. The purpose of\nmonitoring the temperature is to maintain the infant in a thermoneutral environmental zone. This physiological zone is\ndefined as the narrow range of environmental temperatures in which the infant maintains a normal body temperature\nwithout increasing his or her metabolic rate and thus oxygen consumption. Although the temperature measurement\ngold standard is the skin electrode, infrared thermography (IRT) should be considered as an effortless and reliable tool\nfor measuring and mapping human skin temperature distribution and assist in assessing thermoregulatory reflexes.\nMethods: Body surface temperature was recorded under several clinical conditions using an infrared thermography\nimaging technique. Temperature distributions were recorded as real-time video, which was analyzed to evaluate mean\nskin temperatures. Emissivity variations were considered for optimal neonatal IRT correction for which the compensation\nvector was overlaid on the tracking algorithm to improve the temperature reading. Finally, a tracking algorithm was\ndesigned for active follow-up of the defined region of interest over a neonate�s geometry.\nResults: The outcomes obtained from the thermal virtual sensor demonstrate its ability to accurately track different\ngeometric profiles and shapes over the external anatomy of a neonate. Only a small percentage of the motion detection\nattempts failed to fit tracking scenarios due to the lack of a properly matching matrix for the ROI profile over neonate�s\nbody surface.\nConclusions: This paper presents the design and implementation of a virtual temperature sensing application that can\nassist neonatologists in interpreting a neonate�s skin temperature patterns. Regarding the surface temperature, the\ninfluence of different environmental conditions inside the incubator has been confirming....
Background: This work investigates the applicability of a novel clustering approach to the segmentation of\nmammographic digital images. The chaotic map clustering algorithm is used to group together similar subsets of\nimage pixels resulting in a medically meaningful partition of the mammography.\nMethods: The image is divided into pixels subsets characterized by a set of conveniently chosen features and each\nof the corresponding points in the feature space is associated to a map. A mutual coupling strength between the\nmaps depending on the associated distance between feature space points is subsequently introduced. On the\nsystem of maps, the simulated evolution through chaotic dynamics leads to its natural partitioning, which\ncorresponds to a particular segmentation scheme of the initial mammographic image.\nResults: The system provides a high recognition rate for small mass lesions (about 94% correctly segmented inside\nthe breast) and the reproduction of the shape of regions with denser micro-calcifications in about 2/3 of the cases,\nwhile being less effective on identification of larger mass lesions.\nConclusions: We can summarize our analysis by asserting that due to the particularities of the mammographic\nimages, the chaotic map clustering algorithm should not be used as the sole method of segmentation. It is rather\nthe joint use of this method along with other segmentation techniques that could be successfully used for\nincreasing the segmentation performance and for providing extra information for the subsequent analysis stages\nsuch as the classification of the segmented ROI....
Background: Size and shape of the treatment zone after Irreversible electroporation (IRE) can be difficult to depict\ndue to the use of multiple applicators with complex spatial configuration. Exact geometrical definition of the\ntreatment zone, however, is mandatory for acute treatment control since incomplete tumor coverage results in\nlimited oncological outcome. In this study, the ââ?¬Å?Chebyshev Center Conceptââ?¬Â was introduced for CT 3d rendering to\nassess size and position of the maximum treatable tumor at a specific safety margin.\nMethods: In seven pig livers, three different IRE protocols were applied to create treatment zones of different size\nand shape: Protocol 1 (n = 5 IREs), Protocol 2 (n = 5 IREs), and Protocol 3 (n = 5 IREs). Contrast-enhanced CT was\nused to assess the treatment zones. Technique A consisted of a semi-automated software prototype for CT 3d\nrendering with the ââ?¬Å?Chebyshev Center Conceptââ?¬Â implemented (the ââ?¬Å?Chebyshev Centerââ?¬Â is the center of the largest\ninscribed sphere within the treatment zone) with automated definition of parameters for size, shape and position.\nTechnique B consisted of standard CT 3d analysis with manual definition of the same parameters but position.\nResults: For Protocol 1 and 2, short diameter of the treatment zone and diameter of the largest inscribed sphere\nwithin the treatment zone were not significantly different between Technique A and B. For Protocol 3, short\ndiameter of the treatment zone and diameter of the largest inscribed sphere within the treatment zone were\nsignificantly smaller for Technique A compared with Technique B (41.1 Ã?± 13.1 mm versus 53.8 Ã?± 1.1 mm and 39.0 Ã?±\n8.4 mm versus 53.8 Ã?± 1.1 mm; p < 0.05 and p < 0.01). For Protocol 1, 2 and 3, sphericity of the treatment zone was\nsignificantly larger for Technique A compared with B.\nConclusions: Regarding size and shape of the treatment zone after IRE, CT 3d rendering with the ââ?¬Å?Chebyshev\nCenter Conceptââ?¬Â implemented provides significantly different results compared with standard CT 3d analysis. Since\nthe latter overestimates the size of the treatment zone, the ââ?¬Å?Chebyshev Center Conceptââ?¬Â could be used for a more\nobjective acute treatment control....
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