David Rotger, Petia Radeva, & O. Rodriguez. (2006). Vessel Tortuosity Extraction from IVUS Images.
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David Rotger, Petia Radeva, E Fernandez-Nofrerias, & J. Mauri. (2007). Blood Detection In IVUS Longitudinal Cuts Using AdaBoost With a Novel Feature Stability Criterion. In Artificial Intelligence Research and Development. Proceedings of the 10th International Conference of the ACIA (Vol. 163, 197–204).
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David Rotger, Petia Radeva, E Fernandez-Nofrerias, & J. Mauri. (2007). Blood Detection in IVUS Images for 3D Volume of Lumen Changes Measurement Due to Different Drugs Administration. In Computer Analysis of Images and Patterns, 12th International Conference (Vol. 4673, 285–292). LNCS.
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Maya Dimitrova, Ch. Roumenin, Siya Lozanova, David Rotger, & Petia Radeva. (2007). An Interface System Based on Multimodal Principle for Cardiological Diagnosis Assistance. In International Conference On Computer Systems And Technologies (Vol. IIIB.4, 1–6).
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Joel Barajas, Karla Lizbeth Caballero, & Petia Radeva. (2007). Cardiac Phase Extraction in IVUS Sequences Using 1-D Gabor Filters. In Engineering in Medicine and Biology Society, 29th Annual International Conference of the IEEE (343–36).
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Karla Lizbeth Caballero, Joel Barajas, & Petia Radeva. (2007). Using Reconstructed IVUS Images for Coronary Plaque Classification. In Engineering in Medicine and Biology Society, 29th Annual International Conference of the IEEE (2167–2170).
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S. Tanimoto, N. Bruining, David Rotger, Petia Radeva, J. Ligthart, R.T. van Domburg, et al. (2008). Late Stent Recoil of the Bioabsorbable Everolimus Eluting Coronary Stent and its Relationship with Stent Struts Distribution and Plaque Morphology. Journal of the American College of Cardiology, vol. 52(20):1616–1620.
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E. Provenzi, Carlo Gatta, M. Fierro, & A. Rizzi. (2008). A Spatially Variant White-Patch and Gray-World Method for Color Image Enhancement Driven by Local Constant. TPAMI - IEEE Transactions on Pattern Analysis and Machine Intelligence, 1757–1770.
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C. Malagelada, Fosca De Iorio, Fernando Azpiroz, Anna Accarino, Santiago Segui, Petia Radeva, et al. (2008). New Insight Into Intestinal Motor Function via Noninvasive Endoluminal Image Analysis. Gastroenterology, 1155–1162.
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C. Butakoff, Simone Balocco, F.M. Sukno, C. Hoogendoorn, C. Tobon-Gomez, G. Avegliano, et al. (2016). Left-ventricular Epi- and Endocardium Extraction from 3D Ultrasound Images Using an Automatically Constructed 3D ASM. CMBBE - Computer Methods in Biomechanics and Biomedical Engineering: Imaging and Visualization, 4(5), 265–280.
Abstract: In this paper, we propose an automatic method for constructing an active shape model (ASM) to segment the complete cardiac left ventricle in 3D ultrasound (3DUS) images, which avoids costly manual landmarking. The automatic construction of the ASM has already been addressed in the literature; however, the direct application of these methods to 3DUS is hampered by a high level of noise and artefacts. Therefore, we propose to construct the ASM by fusing the multidetector computed tomography data, to learn the shape, with the artificially generated 3DUS, in order to learn the neighbourhood of the boundaries. Our artificial images were generated by two approaches: a faster one that does not take into account the geometry of the transducer, and a more comprehensive one, implemented in Field II toolbox. The segmentation accuracy of our ASM was evaluated on 20 patients with left-ventricular asynchrony, demonstrating plausibility of the approach.
Keywords: ASM; cardiac segmentation; statistical model; shape model; 3D ultrasound; cardiac segmentation
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Carlo Gatta, Juan Diego Gomez, Francesco Ciompi, O. Rodriguez-Leor, & Petia Radeva. (2009). Toward robust myocardial blush grade estimation in contrast angiography. In 4th Iberian Conference on Pattern Recognition and Image Analysis (Vol. 5524, 249–256). LNCS. Springer Berlin Heidelberg.
Abstract: The assessment of Myocardial Blush Grade after primary angioplasty is a precious diagnostic tool to understand if the patient needs further medication or the use of specifics drugs. Unfortunately, the assessment of MBG is difficult for non highly specialized staff. Experimental data show that there is poor correlation between MBG assessment of low and high specialized staff, thus reducing its applicability. This paper proposes a method able to achieve an objective measure of MBG, or a set of parameters that correlates with the MBG. The method tracks the blush area starting from just one single frame tagged by the physician. As a consequence, the blush area is kept isolated from contaminating phenomena such as diaphragm and arteries movements. We also present a method to extract four parameters that are expected to correlate with the MBG. Preliminary results show that the method is capable of extracting interesting information regarding the behavior of the myocardial perfusion.
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Carlo Gatta, & Petia Radeva. (2009). Bilateral Enhancers. In 16th IEEE International Conference on Image Processing (pp. 3161–3165).
Abstract: Ten years ago the concept of bilateral filtering (BF) became popular in the image processing community. The core of the idea is to blend the effect of a spatial filter, as e.g. the Gaussian filter, with the effect of a filter that acts on image values. The two filters acts on orthogonal domains of a picture: the 2D lattice of the image support and the intensity (or color) domain. The BF approach is an intuitive way to blend these two filters giving rise to algorithms that perform difficult tasks requiring a relatively simple design. In this paper we extend the concept of BF, proposing the bilateral enhancers (BE). We show how to design proper functions to obtain an edge-preserving smoothing and a selective sharpening. Moreover, we show that the proposed algorithm can perform edge-preserving smoothing and selective sharpening simultaneously in a single filtering.
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Oscar Camara, Estanislao Oubel, Gemma Piella, Simone Balocco, Mathieu De Craene, & Alejandro F. Frangi. (2009). Multi-sequence Registration of Cine, Tagged and Delay-Enhancement MRI with Shift Correction and Steerable Pyramid-Based Detagging. In 5th International Conference on Functional Imaging and Modeling of the Heart (Vol. 5528, 330–338). LNCS. Springer Berlin Heidelberg.
Abstract: In this work, we present a registration framework for cardiac cine MRI (cMRI), tagged (tMRI) and delay-enhancement MRI (deMRI), where the two main issues to find an accurate alignment between these images have been taking into account: the presence of tags in tMRI and respiration artifacts in all sequences. A steerable pyramid image decomposition has been used for detagging purposes since it is suitable to extract high-order oriented structures by directional adaptive filtering. Shift correction of cMRI is achieved by firstly maximizing the similarity between the Long Axis and Short Axis cMRI. Subsequently, these shift-corrected images are used as target images in a rigid registration procedure with their corresponding tMRI/deMRI in order to correct their shift. The proposed registration framework has been evaluated by 840 registration tests, considerably improving the alignment of the MR images (mean RMS error of 2.04mm vs. 5.44mm).
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David Rotger, Petia Radeva, & N. Bruining. (2010). Automatic Detection of Bioabsorbable Coronary Stents in IVUS Images using a Cascade of Classifiers. TITB - IEEE Transactions on Information Technology in Biomedicine, 14(2), 535 – 537.
Abstract: Bioabsorbable drug-eluting coronary stents present a very promising improvement to the common metallic ones solving some of the most important problems of stent implantation: the late restenosis. These stents made of poly-L-lactic acid cause a very subtle acoustic shadow (compared to the metallic ones) making difficult the automatic detection and measurements in images. In this paper, we propose a novel approach based on a cascade of GentleBoost classifiers to detect the stent struts using structural features to code the information of the different subregions of the struts. A stochastic gradient descent method is applied to optimize the overall performance of the detector. Validation results of struts detection are very encouraging with an average F-measure of 81%.
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Simone Balocco, O. Basset, G. Courbebaisse, E. Boni, Alejandro F. Frangi, P. Tortoli, et al. (2010). Estimation Of Viscoelastic Properties Of Vessel Walls Using a Computational Model and Doppler Ultrasound. PMB - Physics in Medicine and Biology, 55(12), 3557–3575.
Abstract: Human arteries affected by atherosclerosis are characterized by altered wall viscoelastic properties. The possibility of noninvasively assessing arterial viscoelasticity in vivo would significantly contribute to the early diagnosis and prevention of this disease. This paper presents a noniterative technique to estimate the viscoelastic parameters of a vascular wall Zener model. The approach requires the simultaneous measurement of flow variations and wall displacements, which can be provided by suitable ultrasound Doppler instruments. Viscoelastic parameters are estimated by fitting the theoretical constitutive equations to the experimental measurements using an ARMA parameter approach. The accuracy and sensitivity of the proposed method are tested using reference data generated by numerical simulations of arterial pulsation in which the physiological conditions and the viscoelastic parameters of the model can be suitably varied. The estimated values quantitatively agree with the reference values, showing that the only parameter affected by changing the physiological conditions is viscosity, whose relative error was about 27% even when a poor signal-to-noise ratio is simulated. Finally, the feasibility of the method is illustrated through three measurements made at different flow regimes on a cylindrical vessel phantom, yielding a parameter mean estimation error of 25%.
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