Architectural distortion (AD) is a common cause of false-negatives in mammograms. This lesion usually consists of a central retraction of the connective tissue and a spiculated pattern radiating from it. This pattern is difficult to detect due the complex superposition of breast tissue. This paper presents a novel AD characterization by representing the linear saliency in mammography Regions of Interest (ROI) as a graph composed of nodes corresponding to locations along the ROI boundary and edges with a weight proportional to the line intensity integrals along the path connecting any pair of nodes. A set of eigenvectors from the adjacency matrix is then used to extract discriminant coefficients that represent those nodes with higher salient lines. A dimensionality reduction is further accomplished by selecting the pair of nodes with major contribution for each of the computed eigenvectors. The set of main salient lines is then assembled as a feature vector that inputs a conventional Support Vector Machine (SVM). Experimental results with two benchmark databases, the mini-MIAS and DDSM databases, demonstrate that the proposed linear saliency domain method (LSD) performs well in terms of accuracy. The approach was evaluated with a set of 246 RoI extracted from the DDSM (123 normal tissues and 123 AD) and a set of 38 ROI from the mini-MIAS collections (19 normal tissues and 19 AD) respectively. The classification results showed respectively for both databases an accuracy rate of 89 % and 87 %, a sensitivity rate of 85 % and 95 %, and a specificity rate of 93 % and 84 %. Likewise, the area under curve (A ) of the Receiver Operating Characteristic (ROC) curve was 0.93 for both databases.
Diffusion Weighted (DW) imaging have proven to be useful in brain architectural analyses and in research about the brain tract organization and neuronal connectivity. However, the clinical use of DW images is currently limited by a series of acquisition artifacts, such as the partial volume effect (PVE), that affect the spatial resolution, and therefore, the sensitivity of further DW imaging analysis. In this paper, a new superresolution method is presented, given the redundancy present in this kind of images. The proposed method uses local information and a multiscale Shearlet transformation to represent the directional features and the spectral content of the DW images. A comparison of this proposal with a classical image interpolation method demonstrates an improvement of about 3 dB in the PSNR measure and 4.5% in the SSIM metric.
Acute leukemia is usually diagnosed when a test of peripheral blood shows at least 20% of abnormal immature cells (blasts), a figure even lower in case of recurrent cytogenetic abnormalities. Blast identification is crucial for White Blood Cell (WBC) Counting, which depends on both identifying the cell type and characterizing the cellular morphology, processes susceptible of inter‐ and intraobserver variability. The present work introduces an image combined‐descriptor to detect blasts and determine their probable lineage. This strategy uses an Intra‐nucleus Mosaic pattern (InMop) descriptor that captures subtle nuclei differences within WBCs, and Haralick's statistics which quantify the local structure of both nucleus and cytoplasm. The InMop captures WBC inner‐nucleus structure by applying a multiscale Shearlet decomposition over a repetitive pattern (mosaic) of automatically‐segmented nuclei. As a complement, Haralick's statistics characterize the local structure of the whole cell from an intensity co‐occurrence matrix representation. Both InMoP and Haralick‐based descriptors are calculated using the b‐channel from Lab color‐space. The combined‐descriptor is assessed by differentiating blasts from non‐leukemic cells with support vector machine (SVM) classifiers and different transformation kernels, in two public and independent databases. The first database‐D1 (n=260) is composed of healthy and Acute Lymphoid Leukemia (ALL) single cell images, and second database‐D2 contains Acute Myeloid Leukemia (AML) blasts (n=3,294) and non‐blast (n=15,071) cell images. In a first experiment, blasts vs non‐blast differentiation is performed by training with a subset of D2 (n=6,588) and testing in D1 (n=260), obtaining a training AUC of 0.991±0.002 and AUC=0.782 for the independent validation. A second experiment automatically differentiates AML blasts (260 images from D2) from ALL blasts (260 images from D1), with an AUC of 0.93. In a third experiment, state‐of‐the‐art strategies, VGG16 and RESNEXT convolutional neural networks (CNN), separate blast from non‐blast cells in both databases. The VGG16 showed an AUC of 0.673 and the RESNEXT of 0.75. Reported metrics for all the experiments are area under the ROC curve (AUC), accuracy and F1‐score.This article is protected by copyright. All rights reserved.
Leukemia diagnosis and therapy planning are both based on classifying peripheral blood images, under a high inter/intra observer variability scenario. In such applications, automatic image processing and classification strategies have obtained outstanding recognition results, however they are fully dependent on the quality of the annotated data. Unlike supervised classification approaches which built upon label-transformations, the herein presented methodology introduces an unsupervised White Blood Cell characterization in the latent space of a Variational Autoencoder (VAE). The latent space is constructed upon 128 parameters from 64 gaussian distributions and then a k-means clustering may retrieve leukemia diagnostic meaningful cell groups. The whole procedure is twofold assessed: 1) evaluation of the 128 dimension VAE latent space for differentiating cells with higher diagnostic value (blast cells) from other peripheral blood components under multiple supervised classification strategies, and 2) quantification of VAE-parameter clustering capacity to unsupervised separation of blast and non-blast cells. Obtained accuracies of each experiment, 0.888 and 0.757 respectively, suggest that the presented strategy successfully characterizes white blood cells and provides a representation space where subtle cell differences can be objectively measured.
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