Use Of Texture Analysis Research Articles

Texture analysis of CT images in the characterization of oral cancers involving buccal mucosa

The aim of this study was to investigate the usefulness of texture analysis in the characterization of oral cancers involving the buccal mucosa and to assess its effectiveness in differentiating between the various grades of the tumour. Contrast enhanced CT examination was carried out in 21 patients with carcinoma of the buccal mucosa who had consented to retrospective analysis during a research study that was approved by the institutional review board. Two regions of interest (ROIs) were created, one at the site of the lesion and the other at the contralateral normal side. Texture analysis measures of fractal dimension (FD), lacunarity and grey level co-occurrence matrix (GLCM) were computed for each ROI. The numeric data from the two ROIs were compared and were correlated with the tumour grade as confirmed by biopsy. The difference between the mean FD and GLCM parameters of the lesion vs the normal ROI were statistically significant (p < 0.05); no significant difference was observed between the three grades of tumour for any of the parameters (p > 0.05). Texture analysis on CT images is a potential method in the characterization of oral cancers involving the buccal mucosa and deserves further investigation as a predictor of tumour aggression.

Palaeoclimatic changes in the NW Iberian ­Peninsula during the last 3000 years inferred from ­diagenetic ­proxies in the Ría de Muros sedimentary record

The Ria de Muros is the northernmost of the 4 Rias Baixas and, like the others, is subject to seasonal upwelling. The high organic carbon content of its sediments (average 2.4%) is due to the consequent high primary production together with significant continental input from river discharge and runoff. This high organic carbon content not only favours early diagenesis, but does so to an extent that depends on the relative proportions of labile marine organic carbon and refractory terres- trial organic carbon. Thus, changes in early diagenesis reflected in the mineralogy and/or composi- tion of the Ria's sediments can throw light on the degree of oceanic influence in the Ria, and hence on changes in the circulation and ventilation of its water masses and/or the climate on shore. In this study of sediment cores taken in the outer Ria de Muros, the combined use of textural analysis, mag- netic properties (magnetic susceptibility (κ), ratio of anhysteretic to isothermal remanent magnetisa- tion (ARM:IRM), and median destructive field (MDF)) and geochemical parameters (total concentra- tions of diagenetically stable and mobile elements in sediment and pore water) allowed the identification of a current redox front and 2 palaeosedimentary redox fronts in the sediment record. These fronts originated during periods of high marine/terrestrial organic matter ratio (as inferred from the ratio of total organic carbon to total nitrogen (TOC:TN) and δ 13 C). Sedimentation rates calcu- lated from 14 C dating results identify these periods as known periods of increased upwelling and reduced continental input due to colder, drier climate in the NW Iberian Peninsula, namely the Little Ice Age, the Dark Ages, and first cold period of the Upper Holocene.

MRI Texture Analysis in Multiple Sclerosis: Toward a Clinical Analysis Protocol

Magnetic resonance imaging (MRI)-based texture analysis has been shown to be effective in classifying multiple sclerosis lesions. Regarding the clinical use of texture analysis in multiple sclerosis, our intention was to show which parts of the analysis are sensitive to slight changes in textural data acquisition and which steps tolerate interference. The MRI datasets of 38 multiple sclerosis patients were used in this study. Three imaging sequences were compared in quantitative analyses, including a comparison of anatomical levels of interest, variance between sequential slices and two methods of region of interest drawing. We focused on the classification of white matter and multiple sclerosis lesions in determining the discriminatory power of textural parameters. Analyses were run with MaZda software for texture analysis, and statistical tests were performed for raw parameters. MRI texture analysis based on statistical, autoregressive-model and wavelet-derived texture parameters provided an excellent distinction between the image regions corresponding to multiple sclerosis plaques and white matter or normal-appearing white matter with high accuracy (nonlinear discriminant analysis 96%-100%). There were no significant differences in the classification results between imaging sequences or between anatomical levels. Standardized regions of interest were tolerant of changes within an anatomical level when intra-tissue variance was tested. The MRI texture analysis protocol with fixed imaging sequence and anatomical levels of interest shows promise as a robust quantitative clinical means for evaluating multiple sclerosis lesions.

The Effects of Lactose, Microcrystalline Cellulose and Dicalcium Phosphate on Swelling and Erosion of Compressed HPMC Matrix Tablets: Texture Analyzer.

This paper reviews the use of texture analysis in studying the performance of hydrophilic matrices of highly soluble drugs and different types of excipients (i.e. water-soluble, water-insoluble and swellable, and water insoluble and non-swellable). Tablets were prepared by direct compression, and their swelling and erosion in presence of these different excipients were assessed with the help of volumetric, gravimetric, morphological, and rheological studies. Dissolution test was performed using USP 26 apparatus 2 modified by insertion of a sieve to prevent sticking of the tablets to the bottom of the vessel and allow them to swell 3-dimensionally. Loading 15% of the highly soluble drug in formulations containing 65% lactose showed the most pronounced swelling and erosion and the best sustained drug release, compared to matrices containing microcrystalline cellulose and dicalcium phosphate. The correlation between front movement, mass erosion and solute transport in relation to excipient type on progression of probe displacement and total work was examined throughout texture analysis studies. The formulation containing the soluble excipient lactose showed better swelling and erosion properties compared to formulations containing the swellable and insoluble excipients. In conclusion, it could be said that based on the distinct conventional dosage forms insertion of particular excipients in hydrophilic controlled release tablets containing water soluble drug, the finger print information of drug release profile could be obtained. To study the release profile from hydroxy propyl methyl cellulose K 15M matrices with different types of excpients, diltiazem hydrochloride was used as a model soluble drug.

Segmentation of Myocardial Boundaries in Tagged Cardiac MRI Using Active Contours: A Gradient‐Based Approach Integrating Texture Analysis

The noninvasive assessment of cardiac function is of first importance for the diagnosis of cardiovascular diseases. Among all medical scanners only a few enables radiologists to evaluate the local cardiac motion. Tagged cardiac MRI is one of them. This protocol generates on Short-Axis (SA) sequences a dark grid which is deformed in accordance with the cardiac motion. Tracking the grid allows specialists a local estimation of cardiac geometrical parameters within myocardium. The work described in this paper aims to automate the myocardial contours detection in order to optimize the detection and the tracking of the grid of tags within myocardium. The method we have developed for endocardial and epicardial contours detection is based on the use of texture analysis and active contours models. Texture analysis allows us to define energy maps more efficient than those usually used in active contours methods where attractor is often based on gradient and which were useless in our case of study, for quality of tagged cardiac MRI is very poor.

Usefulness of Texture Analysis for Computerized Classification of Breast Lesions on Mammograms

This work presents the usefulness of texture features in the classification of breast lesions in 5,518 images of regions of interest, which were obtained from the Digital Database for Screening Mammography that included microcalcifications, masses, and normal cases. Sixteen texture features were used, i.e., 13 were based on the spatial gray-level dependence matrix and 3 on the wavelet transform. The nonparametric K-NN classifier was used in the classification stage. The results obtained from receiver operating characteristic analysis indicated that the texture features can be used for separating normal regions and lesions with masses and microcalcifications, yielding the area under the curve (AUC) values of 0.957 and 0.859, respectively. However, the texture features were not very effective for distinguishing between malignant and benign lesions because the AUC was 0.617 for masses and 0.607 for microcalcifications. The study showed that the texture features can be used for the detection of suspicious regions in mammograms.

Use of texture analysis to determine compaction force of powders

A correlation between compaction of powders and texture analysis was studied, using the Texture Analyser-XT2, with the back extrusion A/BE probe to find the necessary force (in grams) to compact the samples. The particle/granules size distribution of the samples, the particle size and the bulk densities were determined to correlate all these physical properties. It was established a relationship between physical properties and the processing of the powder samples. Eleven Brazilian chocolate drink powders were analyzed. The results of compaction force of the samples varied from 532.12 g to 16399.30 g, depending on their ingredients, particle size distribution and type of process. The particle size average of the samples varied from 0.126 to 0.628 mm and the bulk densities, from 0.28 to 0.94 g/mL, showing the differences among the chocolate drink powders.

Use of texture analysis to study hydrophilic solvent effects on the mechanical properties of hard gelatin capsules

The aim of this work was to explore texture analysis for quantitative evaluation of the effect of hydrophilic solvent systems used as capsule fills on the mechanical properties of hard gelatin capsules. For this purpose, a texture analyzer (Stable Micro Systems, model TA.XT Plus) equipped with a capsule separating rod fixture was used. The tests were conducted in a tension mode. Elastic stiffness, tensile force and elongation at break were determined from the experimental stress–strain curve in order to quantitatively describe both brittleness and softening of capsules. In this paper, it has been demonstrated that the effect of various hydrophilic solvent (i.e. propylene glycol (PG), polyethylene glycol 400 (PEG 400), ethanol) mixtures on the mechanical properties of hard gelatin capsules can be easily monitored using texture analysis. Significant counteractive effects between PG and PEG 400 or ethanol on the integrity of capsule shells were discovered in this study. Texture analysis is found to be a convenient tool for studying formulation compatibility. It can be invaluable in early screening studies of liquid filled hard gelatin capsules.

On the Use of Texture Analysis and Orientation Stereology to Investigate Polycrystalline Materials

This paper focus on the use of orientation stereology to understand polycrystalline materials behavior. First some cautions or limits by using this approach are considered. Examples related to phase transformation, plastic deformation or crack propagation are then presented.

The use of textural analysis to locate features in geophysical data

Textural analysis is a powerful tool, but it is rarely applied to geophysical potential field data because the results are often noisy and ambiguous. New texture filters (based on grey-level co-occurrence matrices (GLCMs)) have been specifically designed for gravity and magnetic data, and are useful for the detection of subtle monopolar and dipolar geophysical anomalies. The method uses two GLCM kernels simultaneously; in the first kernel the GLCM vectors are oriented along the contour lines of the feature to be located, and in the second the vectors are oriented in the ‘uphill’ direction, i.e. orthogonal to those of the first kernel. The ratio of the GLCM texture amplitudes from the two kernels then yields a maximum when the kernel is centred over an example of the feature within the data. The method has general application and is not limited to potential fields. It works with any type of target, as long as an example is available. Applications to both synthetic data and real data (from South Africa and Australia) are demonstrated.

Improving Artificial Neural Networks Using Texture Analysis and Decision Trees for the Classification of Land Cover

The purpose of this research was to improve artificial neural network (ANN) classification of land cover using texture analysis and decision trees. Three variants on ANN-based classifiers were applied to Landsat-7 data of southwestern Ohio for an Anderson Level-II land-cover classification: (1) the use of a customized architecture for each land-cover class; (2) the use of texture analysis for urban classes; and (3) the use of a decision tree (DT) classifier to refine the ANN output. An accuracy assessment was performed on the final ANN classification and compared to the USGS National Land Cover Data (NLCD). Overall accuracy of the ANN was 85%, compared to 69% for the NLCD. Producer accuracies for the ANN ranged from 64% to 96% compared to 29 to 86% for the NLCD. User accuracies for the ANN ranged from 71 to 99% compared to 36-87% for the NLCD. The ANN methodology will be used to classify the state of Ohio and could potentially be used on a national scale.

Texture evaluation of RADARSAT imagery for wetland mapping

Wetland studies have shown that single-date radar satellite images produce poor land cover classification results, whereas the results obtained from multi-date radar images are comparable with those obtained from optical satellite images. In some cases however, only single-date data are available. Therefore, improving the classification accuracy of single-date radar images is valuable because they provide a reliable alternative to optical images, whose accessibility is limited due to the presence of cloud. This paper evaluates the use of texture analysis on the single-date radar satellite imagery for wetland classification. A single-date RADARSAT image is used to classify the wetland and other land cover types in Walpole Island, Ontario, Canada. The grey-level co-occurrence matrix (GLCM) is employed for texture measurement, and a maximum likelihood supervised classifier is used for classification. Considerations are given to the combination of texture features and GLCM input parameters, such as window size, inter-pixel distance, and inter-pixel angle. The results of this study indicate that texture analysis of a single-date RADARSAT image greatly improved the wetland classification accuracy. Selecting the suitable combination of texture features and using the appropriate input parameters to generate these texture features are crucial to obtaining the best results.

The use of texture analysis to assess the structural strength of hoof horn of dairy cows

The quality of hoof horn is related to 3 factors: architecture of the Stratum corneum (number of tubules and inter-tubular space), cellular factors (type of keratinization, orientation of keratin fibres) and inter-cellular factors (amount and chemical composition of the inter-cellular substance (Pellman et al., 1993). Kempson and Logue (1993) related poor hoof horn quality at 1 month before calving to the occurrence of moderate to severe solar haemorrhage at 10 to 20 weeks after calving. The objective of this experiment was to develop the use of texture analysis as a method to measure the structural strength of hoof sole tissue and assess the influence of sample width and bruising on structural strength.

The use of reticulated foam in texture test objects for magnetic resonance imaging

The use of texture analysis in magnetic resonance imaging requires the availability of texture test objects for use in standardisation of in vivo measurement. A series of such objects of varying texture has been developed using reticulated foam, which has an open pore structure. The texture properties of these foams have been compared with in vivo brain and the ability of texture analysis to discriminate the different porosities of foam and brain (white matter) demonstrated.

The effects of alginate molecular structure and formulation variables on the physical characteristics of alginate raft systems

A study has been conducted in order to assess the effects of alginate molecular structure and formulation variables on alginate raft strength and dimensions. In addition, the use of texture analysis as a novel means of characterising alginate raft systems has been investigated. Five alginates of known molecular composition were used (LFR 5/60, LF 120M, LF 10/40RB, LF 20/200 and LF 200DL), while two gas-forming agents (sodium and potassium bicarbonate) and two divalent cationic salts (calcium carbonate and zinc carbonate) were studied. The effects of acid strength on raft formation was also investigated. It was noted that the inclusion of divalent cations and the use of the lowest molecular weight alginate sample (LFR 5/60) increased the volume of the resulting rafts. Texture analysis measurements allowed both the maximum breaking strength and the work involved during the rupture process to be quantified. Inclusion of divalent cations (particularly calcium) increased the raft strength, while inclusion of potassium carbonate resulted in stronger rafts than did sodium carbonate. Alginates with higher guluronic acid contents resulted in stronger rafts, with the exception of LFR 5/60 which yielded weaker rafts despite the high G ratio, probably as a result of the lower molecular weight of this material. Raft volume and strength increased with decreasing pH of the raft forming media.

The use of texture analysis to study the time course of chromatolysis

Image analysis of the textural feature entropy of the Nissl substance was used to monitor the time course of chromatolysis in regenerating hypoglossal motoneurons and degenerating facial motoneurons 4–112 days after hypoglossal–facial anastomosis in rats. Changes in the Nissl substance were detected that were not obvious on the basis of subjective judgement of the light-microscopical appearance of the neurons. Chromatolysis started 4 days post operation (dpo) and was not reversed at 112 dpo in both nuclei. The increase of chromatolysis was 14–28 dpo faster in the regenerating hypoglossal neurons than in degenerating facial neurons. Maximal chromatolysis was measured at 56–70 dpo in both nuclei. Afterwards chromatolysis persisted at a significantly higher level in the degenerating facial motoneuron pool. In conclusion, chromatolysis is a very long persisting reaction. In the beginning chromatolysis is faster and greater in regenerating rather than in degenerating neurons. In contrast, passing the maximal reaction, chromatolysis is maintained at a higher level in degenerating motoneurons. Image analysis of textural features is a suitable and reliable tool to monitor the time course of neuronal cell body changes. The presented quantitative method could be applied in any neurobiological study influencing the regeneration or degeneration of motoneurons.

Use of Texture Analysis for the Characterisation of Cu - 30 at.% Ni Droplets Solidified at Selected Undercoolings

Use of Texture Analysis for the Characterisation of Cu - 30 at.% Ni Droplets Solidified at Selected Undercoolings

The use of texture analysis to delineate suspicious masses in mammography

In mammography, national breast screening programmes have lead to a large increase in the number of mammograms needing to be studied by radiologists. Lesion indicators can be pointlike as in microcalcifications or extended as in stellate (spiculate) lesions or regular masses. Texture analysis has been proposed as a promising method for studying radiographic images in relation to the quantitation of extended objects. Filters have been designed, which may be used to segment or classify an image using textural features, and these have been reported as being of value in automatic mammographic glandular tissue classification. The work reported here suggests the incorporation of additional steps of image processing in an attempt to improve the performance of these filters in the quantitation of lesions. By deriving approximate outlines, which are used to identify suspicious regions, the investigation illustrates the properties of one of the filters. After applying the method to a small prediagnosed database of stellate lesions and regular masses, the results show that the filter is able to outline the malignant masses in all cases presented. The erroneous areas extracted are small for the initial part of the work, which deals with 256*256 pixel image extracts, though slightly larger in some cases when the whole mammogram is considered. Simple methods for the removal of these artefacts are proposed. For each non-suspicious case studied, the sum of any false positive areas is statistically insignificant when compared with the regions correctly outlined in the prediagnosed instances.

Trabecular texture analysis of CT images in the relationship with spinal fracture.

To evaluate age-related changes in trabecular texture and bone mineral density (BMD) and to determine the usefulness of texture analysis in the assessment of the risk of fracture. The vertebral trabecular BMD was measured in 209 women aged 18-86 years. Run length analysis was applied to computed tomographic images obtained with 2-mm section thickness. The width of the trabecula (T-texture) and the width of the intertrabecular space (I-texture) were calculated. I-texture significantly increased with age in women 50 years of age or older (P < .0001). Women with fracture had significantly lower BMD (P < .0001 at 60-69 years, P < .05 at 70-79 years) and significantly higher I-texture (P < .05 at 60-69 years, P < .01 at 70-79 years). For fracture risk, BMD had the highest sensitivity and I-texture had the highest specificity in women aged 60-69 years; I-texture had the highest sensitivity and specificity in women aged 70-79 years. Texture analysis was helpful in the assessment of fracture risk, especially in elderly women.

The use of texture analysis for the discrimination of Nissl substance in neurons

Structural changes induced by cordotomy in the Nissl substance of identifiable spinal motoneurons innervating the white musculature of the European eel were quantified with the use of texture features calculated from digitized images. Data were evaluated and the motoneurons classified by using multivariate analysis. The study shows that there are differences in the structural organization of the Nissl substance of motoneurons taken from control and cordotomized fishes. Distinction could only be made by using texture features, as visual examination of the motoneurons did not reveal any alteration of the studied cellular substance. Reorganization of the Nissl substance might be the result of a changed protein metabolism or a changed neuronal activity pattern consequent upon cordotomy. The method employs quick and simple techniques and could be useful in several other neurobiological studies.