Patients with Mild Cognitive Impairment (MCI) have an increased risk of Alzheimer's disease (AD). Early identification of underlying neurodegenerative processes is essential to provide treatment ...before the disease is well established in the brain. Here we used longitudinal data from the ADNI database to investigate prediction of a trajectory towards AD in a group of patients defined as MCI at a baseline examination. One group remained stable over time (sMCI, n = 357) and one converted to AD (cAD, n = 321). By running two independent classification methods within a machine learning framework, with cognitive function, hippocampal volume and genetic APOE status as features, we obtained a cross-validation classification accuracy of about 70%. This level of accuracy was confirmed across different classification methods and validation procedures. Moreover, the sets of misclassified subjects had a large overlap between the two models. Impaired memory function was consistently found to be one of the core symptoms of MCI patients on a trajectory towards AD. The prediction above chance level shown in the present study should inspire further work to develop tools that can aid clinicians in making prognostic decisions.
The drift in the stock price and the occurring of the transaction costs in the stock market can significantly affect the profitability of the investment in the stock. in the article the model of the ...market is described with the stock price drift and two sources of the transaction costs: bid-ask spread and market impact. in the considered model, the trading strategy which maximizes the expected amount of money received from selling the shares of the stock of the market participant subject to the constraint of the constant trading velocity is explicitly determined. The numerical example is also included.
Susceptibility weighted imaging (SWI) is a novel MRI sequence which demonstrates the susceptibility differences between adjacent tissues and it is promising to be a sequence useful in the assessment ...of brain tumors vascularity. The aim of our study was to demonstrate usefulness of SWI in evaluation of intratumoral vessels in comparison to CET1 sequence in a standardized, objective manner.
10 patients with supratentorial brain tumors were included in the study. All of them underwent conventional MRI examination with a 1,5 T scanner. SWI sequence was additionally performed using the following parameters: TR 49 ms,TE 40 ms. We used authors' personal computer software - Vessels View, to assess the vessels number.
Comparison of SWI and CET1 sequences was performed using our program. Analysis of all 26 ROIs demonstrated predominance of SWI in the amount of white pixels (vessel cross-sectional) and a similar number of elongated structures (blood vessels).
To conclude, the results of this study are encouraging; they confirm the added value of SWI as an appropriate and useful sequence in the process of evaluation of intratumoral vascularity. Using our program significantly improved visualization of blood vessels in cerebral tumors. The Vessel View application assists radiologists in demonstrating the vessels and facilitates distinguishing them from adjacent tissues in the image.
In the paper hedging of the European option in a discrete time financial market with proportional transaction costs is studied. It is shown that for a certain class of options the set of portfolios ...which allow to hedge an option in a discrete time model with a bounded set of possible changes in a stock price is the same as the set of such portfolios, under assumption that the stock price evolution is given by a suitable CRR model. PUBLICATION ABSTRACT
Magnetic resonance imaging has achieved an increasingly important role in the clinical work-up of renal diseases such chronic kidney disease (CKD). A large panel of parameters have been proposed to ...diagnose CKD among them total kidney volume (TKV) which recently qualified as biomarker. Volume estimation in renal MRI is based on image segmentation of the kidney and/or its compartments. Beyond volume estimation renal segmentation supports also the quantification of other MR based parameters such as perfusion or filtration. The aim of the present article is to discuss the recent existing literature on renal image segmentation techniques and show today's limitations of the proposed techniques that might hinder clinical translation. We also provide pointers to open source software related to renal image segmentation.
Liquidity is an important characteristic of a stock traded on thestock exchange. The expected value of transaction costs, which takes intoaccount the transaction's volume and duration, may be a ...consideredas an important measure of a liquidity of a traded stock. In this paper theformulas for expected transaction cost, caused by bid-ask spread and marketimpact are presented. Moreover, in this article, the problem of determininga duration of a transaction of a stock sale which minimizes the transactioncost and takes into account the forecast of the expected stock price on thestock exchange, is considered
Possibilities of constructing an anatomically correct and accurate geometric model of brain blood vessels basing on clinical 1.5T magnetic resonance images are explored. A high-resolution ToF MR ...image (0.49 mm 3 voxel) was used to build a reference geometric model of selected real-brain arteries. This model was STL-described and 3D printed using a photopolymer material. The printed phantom was submerged in water and scanned using a low-resolution clinical MR system (0.33×0.33×2.2 mm). Level-set segmentation of the obtained T2 images showed significant staircase effect. After T2 image resampling to 0.33mm 3 voxel size, the model walls become smoother, but thin branches were still missing. A Frangi filtering-based, smooth centerline-radius vessel branches description was then developed to achieve their correct reconstruction with subvoxel accuracy. Challenges of MRI acquisition of 3D printed models are discussed.
On extracting skeletons from binary 3D images Zasinski, Piotr; Kocinski, Marek; Materka, Andrzej
2017 International Conference on Systems, Signals and Image Processing (IWSSIP)
Conference Proceeding
This paper explores the subject of extracting skeletons from 3D binary images. It draws attention to the flaws found in the available skeletonization implementations. The most popular algorithm ...devised by Lee, Kashyap and Chu is analyzed. It is shown that despite good results, some aspects of said algorithm can be further improved upon. An own implementation, with some modifications is made and compared against the existing ones.
The aim of this article is to analyse the major sources of transaction costs in financial markets, in particular to find the amounts of such costs on the Warsaw Stock Exchange (WSE). Sources of ...transaction costs are considered: commissions, bid-ask spread and market impact. The commissions are only briefly described since they are explicitly stated and easily measured. More attention is paid to the bid-ask spread which is one of the main causes of trading costs. It is shown that the investor who wants to outperform the Polish market should usually expect a much higher bid-ask spread than it follows from the officially used calculations. Then it is demonstrated how historical spreads can be used in predicting their future values. This seems to be important from the practical point of view, since forecasting trading costs is a compelling task for financial managers. Next, market impact and market impact costs are considered. The practical method of measuring these is applied and discussed.
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