120 research outputs found

    The value of diffusion-weighted imaging in assessing the ADC changes of tissues adjacent to breast carcinoma

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    <p>Abstract</p> <p>Background</p> <p>To define a threshold value of apparent diffusion coefficient (ADC) with which malignant breast lesions can be distinguished from benign lesions, and to evaluate the ADC change of peri-tumor tissue in breast carcinoma by echo planar-diffusion weighted imaging (EPI-DWI).</p> <p>Methods</p> <p>57 breast lesions were scanned by routine MRI and EPI-DWI. The ADC values were compared between malignant and benign lesions. The sensitivity and specificity of EPI-DWI and the threshold ADC value were evaluated by Receiver Operating Characteristic curve (ROC). The ADC values of malignant lesion and layered peri-tumor tissues (from innermost layer 1 to outermost layer 4 with 5 mm every layer) in different directions were compared and the ADC values among different layers were compared.</p> <p>Results</p> <p>The ADC value of 35 malignant lesions was statistically lower than that of 22 benign lesions (P < 0.05). In ROC curve, the threshold value was 1.24 +/- 0.25*10E-3 mm<sup>2</sup>/s (b = 500) or 1.20 +/- 0.25*10E-3 mm<sup>2</sup>/s (b = 1000). The ADC value of malignant lesions was statistically lower than that of peri-tumor tissues in different directions (P < 0.05). For peri-tumor tissues, the ADC values increased gradually from layer 1 to layer 4 and there was a significant difference between the ADC values of layer 1 and layer 2 (P < 0.05); while from layer 2 outwards, there was no statistical difference among different layers.</p> <p>Conclusion</p> <p>ADC value was a sensitive and specific parameter that could help to differentiate benign and malignant breast lesions. ADC changes in tissues adjacent to breast carcinoma could be detected by EPI-DWI, which made EPI-DWI a promising method for helping to determine surgical scope of breast carcinoma.</p

    The significance of radiographic and ultrasonographic findings in the management of necrotising enterocolitis - results from a survey

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    Necrotising Enterocolitis (NEC) remains a potentially devastating emergency in neonates, predominantly the premature. Ever since it was first described in the 60's, imaging has played a great role in definition, staging, and monitoring of the disease. The radiographic image can change before the clinical condition, but typical signs are often transient and may be missing even in severe NEC [1-4]. These circumstances have led to the recommendation of frequent imaging and to the insight that the clinical decisions cannot rely solely on radiological signs [5-7]. Ultrasound (US) as a possibility to enhance sensitivity and diagnostic accuracy was first described in the mid 80's [8, 9] and was included in a diagnostic algorithm suggested by in 1994 [6], but despite great effort to develop and validate the method, its role in the management of NEC has not yet been established [7, 10, 11]. Meanwhile, in order to improve interobserver agreement and diagnostic accuracy of AR, the radiographic signs of NEC have also been systematized into the DAAS scale [12]. Imaging, as an adjunct to clinical assessment [11], is crucial in the diagnosis and management of NEC. The purpose of this survey was to investigate current views and routines, as described by involved specialists, and identify areas in need of further study and discussion.Finns en kompletteranade e-poster, B-0513, med DOI: 10.1594/ecr2017/B-0513Länk till muntlig presentation: http://ecronline.myesr.org/ecr2017/?p=recording&amp;t=recorded&amp;lecture=the-significance-of-radiographic-and-ultrasonographic-findings-in-the-management-of-necrotising-enterocolitis-results-from-a-survey-1</p

    The role of imaging in the management of necrotising enterocolitis : a multispecialist survey and a review of the literature

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    Objectives To investigate current practices and perceptions of imaging in necrotising enterocolitis (NEC) according to involved specialists, put them in the context of current literature, and identify needs for further investigation. Methods Two hundred two neonatologists, paediatric surgeons, and radiologists answered a web-based questionnaire about imaging in NEC at their hospitals. The results were descriptively analysed, using proportion estimates with 95% confidence intervals. Results There was over 90% agreement on the value of imaging for confirmation of the diagnosis, surveillance, and guidance in decisions on surgery as well as on abdominal radiography as the first-choice modality and the most important radiographic signs. More variation was observed regarding some indications for surgery and the use of some ultrasonographic signs. Fifty-eight per cent stated that ultrasound was used for NEC at their hospital. Examination frequency, often once daily or more but with considerable variations, and projections used in AR were usually decided individually rather than according to fixed schedules. Predicting the need of surgery was regarded more important than formal staging. Conclusion Despite great agreement on the purposes of imaging in NEC and the most important radiographic signs of the disease, there was considerable diversity in routines, especially regarding examination frequency and the use of ultrasound. Apart from continuing validation of ultrasound, important objectives for future studies include definition of the supplementary roles of both imaging modalities in relation to other diagnostic parameters and evaluation of various imaging routines in relation to timing of surgery, complications, and mortality rate

    Vliv substituci na vlastnosti supravodicu typu Bi-Sr-Ca-Cu-O

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    Available from STL Prague, CZ / NTK - National Technical LibrarySIGLECZCzech Republi

    Eu-DOPED La1-xYxAlO₃: IMPACT Of Y/La RATIO ON OPTICAL PROPERTIES

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    YAlO₃ and LaAlO₃ are both important oxides used as matrices in optical applications. Their mutual solid solubility is kinetically dependent, especially in a polycrystalline form. In this work, we prepared La1-xYxAlO₃ (x = 0-0.65) samples doped with 5 at% of Eu3+ in the A-site. The samples were prepared by Spark Plasma Sintering from powders synthetised by a reverse co-precipitation method. The single-phase samples were obtained up to a composition of La0.7Y0.25Eu0.05AlO₃; with a higher yttrium doping level, a mixture of Y-rich and La-rich perovskite-type phases was present. The La/Y substitution had an influence on a shift in the top of the valence band which influenced the excitation spectra. In photoluminescence and radioluminescence measurements, the Eu3+ local site symmetry changes were manifested by the change in intensity and fine splitting of the ⁵D0⟶⁷FJ (J = 1, 2, 3, 4, 5) emission bands. The increasing content of Y3+ caused a slight acceleration of the PL decay of the Eu3+ photoluminescence and an increase in the integral intensity of radioluminescence spectra
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