scholarly journals Enhanced diffuse optical tomographic reconstruction using concurrent ultrasound information

Author(s):  
G. Di Sciacca ◽  
L. Di Sieno ◽  
A. Farina ◽  
P. Lanka ◽  
E. Venturini ◽  
...  

Multimodal imaging is an active branch of research as it has the potential to improve common medical imaging techniques. Diffuse optical tomography (DOT) is an example of a low resolution, functional imaging modality that typically has very low resolution due to the ill-posedness of its underlying inverse problem. Combining the functional information of DOT with a high resolution structural imaging modality has been studied widely. In particular, the combination of DOT with ultrasound (US) could serve as a useful tool for clinicians for the formulation of accurate diagnosis of breast lesions. In this paper, we propose a novel method for US-guided DOT reconstruction using a portable time-domain measurement system. B-mode US imaging is used to retrieve morphological information on the probed tissues by means of a semi-automatical segmentation procedure based on active contour fitting. A two-dimensional to three-dimensional extrapolation procedure, based on the concept of distance transform, is then applied to generate a three-dimensional edge-weighting prior for the regularization of DOT. The reconstruction procedure has been tested on experimental data obtained on specifically designed dual-modality silicon phantoms. Results show a substantial quantification improvement upon the application of the implemented technique. This article is part of the theme issue ‘Synergistic tomographic image reconstruction: part 2’.

2014 ◽  
Vol 22 (3) ◽  
Author(s):  
Caifang Wang

Abstract.Diffuse optical tomography (DOT) is an optical imaging modality, which provides the spatial distribution of the optical parameters inside a random medium. A propagation back-propagation method named EM-like reconstruction method for stationary DOT problem has been proposed yet. This method is really time consuming. Hence the ordered-subsets (OS) technique for this reconstruction method is studied in this paper. The boundary measurements of DOT are grouped into nonoverlapping and overlapping ordered sequence of subsets with random partition, sequential partition and periodic partition, respectively. The performance of OS methods is compared with the standard EM-like reconstruction method with two-dimensional and three-dimensional numerical experiments. The numerical experiments indicate that reconstruction of nonoverlapping subsets with periodic partition, overlapping subsets with periodic partition and standard EM-like method provide very similar acceptable reconstruction results. However, reconstruction of nonoverlapping subsets with periodic partition spends a minimum of time to get proper results.


2016 ◽  
Vol 8 (3) ◽  
pp. 151-156
Author(s):  
Javier Elías Fernández

El foramen mentoniano accesorio es un orificio adicional al foramen mentoniano que se localiza en la cara anterolateral externa del cuerpo mandibular y que se conecta con el conducto dentario inferior.  Su ubicación es posteroinferior al foramen mentoniano.  De acuerdo a su clasificación también se lo conoce como foramen mental doble, foramen mental adicional, foramen mental múltiple, foramen mental accesorio o foramen mandibular bucal suplementario. Su frecuencia de aparición varía del 1% al 10 %, cuando son unilaterales y del 0,47% al 1,2% cuando son bilaterales.  El  foramen mentoniano accesorio es una rara variante anatómica de poca frecuencia pero de gran relevancia clínico-quirúrgica ya que está asociado a un paquete vasculonervioso por lo cual es necesario su diagnóstico radiográfico ya sea por métodos convencionales o por alta resolución para evitar posibles complicaciones en los diferentes procedimientos odontológicos. Se presenta un caso de foramen mentoniano accesorio de un paciente remitido al Servicio de Radiología de la Facultad de Odontología de la UNC. La tomografía computada constituye el estudio por imágenes de excelencia ante la presunción de un foramen accesorio ya que los diferentes cortes tomográficos y la reconstrucción 3D nos permiten localizarlo de manera precisa e inequívoca. Constituye generalmente un hallazgo radiográfico o se observa durante procedimientos quirúrgicos al quedar al descubierto por el desplazamiento de los tejidos blandos. Cuando se localiza antes de cualquier procedimiento odontológico se deben tomar todos los recaudos necesarios para evitar daño del paquete vasculonervioso y futuras complicaciones como hemorragias o parestesias, principalmente en prácticas como la colocación de implantes dentales o las apicectomías. Accessory mental foramen (AMF) is defined as any openings in addition to mental foramen, with connection to the mandibular canal in the anterolateral aspect of mandible. According to its classification, an AMF is known as double mental foramen, additional mental foramen, multiple mental foramen, supplementary mandibular buccal foramen. The accessory mental foramen is a radiological finding or is detected during surgical procedures. Its prevalence ranges from 1.4 to 10% when it is unilateral and ranges from 0,47% to 1,2% when it is bilateral. Accessory mental foramen is an important and rare anatomical variation associated with a neurovascular bundle. Its prevalence is low. The diagnosis by conventional radiological methods or three-dimensional radiographic imaging techniques is effective to avoid complications in dental procedures. An accessory mental foramen case of a male patient referred to the Department of Radiology at the National University of Córdoba School of Dentistry is reported. The computed tomography is the most accurate imaging modality for the identification of an accessory foramen through multiplanar reformatted images and three dimensional images. When the existence of AMF is identified before dental procedures, appropriate actions should be taken to avoid damages of the neurovascular bundle and eventual complications such as hemorrhage and paresthesia principally in procedures like dental implant insertion or periapical surgery.


2021 ◽  
Vol 11 (3) ◽  
pp. 1028-1036
Author(s):  
Ziqiang Zhou

Ultrasound imaging technology can not only show neck tear the degree and extent of disease, to help make the correct diagnosis, can also be used to assess shoulder neck inflammation after surgery to repair a shoulder muscle neck tissue integrity and healing. Ultrasound imaging with high-resolution, real-time operation, low cost, etc. gradually become shoulder neck inflammatory disease preferred imaging modality. The sensitivity and specificity for three-dimensional ultrasound imaging of shoulder neck inflammation were 78% and 93% in this study. The full-thickness inflammation sensitivity and specificity were 50% and 95%. The sensitivity and specificity of inflammation were 57% and 87%, respectively. This study shows that the diagnostic accuracy of 3D ultrasound imaging in shoulder and neck inflammation and surrounding tissue lesions is close to that of MRI. Three-dimensional appearance of new technologies such as ultrasound imaging will further improve ultrasound imaging techniques in shoulder neck inflammation application in the diagnosis and treatment assessment.


2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Gisele C. Pereira ◽  
Melanie Traughber ◽  
Raymond F. Muzic

The use of ionizing radiation for cancer treatment has undergone extraordinary development during the past hundred years. The advancement of medical imaging has been critical in helping to achieve this change. The invention of computed tomography (CT) was pivotal in the development of treatment planning. Despite some disadvantages, CT remains the only three-dimensional imaging modality used for dose calculation. Newer image modalities, such as magnetic resonance (MR) imaging and positron emission tomography (PET), are also used secondarily in the treatment-planning process. MR, with its better tissue contrast and resolution than those of CT, improves tumor definition compared with CT planning alone. PET also provides metabolic information to supplement the CT and MR anatomical information. With emerging molecular imaging techniques, the ability to visualize and characterize tumors with regard to their metabolic profile, active pathways, and genetic markers, both across different tumors and within individual, heterogeneous tumors, will inform clinicians regarding the treatment options most likely to benefit a patient and to detect at the earliest time possible if and where a chosen therapy is working. In the post-human-genome era, multimodality scanners such as PET/CT and PET/MR will provide optimal tumor targeting information.


Author(s):  
Charalampos Tsoumpas ◽  
Jakob Sauer Jørgensen ◽  
Christoph Kolbitsch ◽  
Kris Thielemans

This special issue is the second part of a themed issue that focuses on synergistic tomographic image reconstruction and includes a range of contributions in multiple disciplines and application areas. The primary subject of study lies within inverse problems which are tackled with various methods including statistical and computational approaches. This volume covers algorithms and methods for a wide range of imaging techniques such as spectral X-ray computed tomography (CT), positron emission tomography combined with CT or magnetic resonance imaging, bioluminescence imaging and fluorescence-mediated imaging as well as diffuse optical tomography combined with ultrasound. Some of the articles demonstrate their utility on real-world challenges, either medical applications (e.g. motion compensation for imaging patients) or applications in material sciences (e.g. material decomposition and characterization). One of the desired outcomes of the special issues is to bring together different scientific communities which do not usually interact as they do not share the same platforms such as journals and conferences. This article is part of the theme issue ‘Synergistic tomographic image reconstruction: part 2’.


2016 ◽  
Vol 18 (1) ◽  
pp. 96 ◽  
Author(s):  
Zeno Spârchez ◽  
Tudor Mocan ◽  
Pompilia Radu ◽  
Ofelia Anton ◽  
Nicolae Bolog

Abstract. The last decades have known continuous development of therapeutic strategies in hepatocellular carcinoma (HCC). Unfortunately the disease it still not diagnosed until it is already at an intermediate or even an advanced disease. In these circumstances transarterial chemoembolization (TACE) is considered an effective treatment for HCC. The most important independent prognostic factor of both disease free survival and overall survival is the presence of complete necrosis. Therefore, treatment outcomes are dictated by the proper use of radiological imaging. Current guidelines recommend contrast enhanced computer tomography (CECT) as the standard imaging technique for evaluating the therapeutic response in patients with HCC after TACE. One of the most important disadvantage of CECT is the overestimation of tumor response. As an attempt to overcome this limitation contrast enhanced ultrasound (CEUS) has gained particular attention as an imaging modality in HCC patients after TACE. Of all available imaging modalities, CEUS performs better in the early and very early assessment of TACE especially after lipiodol TACE. As any other imaging techniques CEUS has disadvantages especially in hypovascular tumors or in cases of tumor multiplicity. Not far from now the current limitations of CEUS will be overcome by the new CEUS techniques that are already tested in clinical practice such as dynamic CEUS with quantification, three-dimensional CEUS or fusion techniques.


2018 ◽  
Vol 25 (6) ◽  
pp. 1819-1826 ◽  
Author(s):  
Haiyan Yu ◽  
Sihao Xia ◽  
Chenxi Wei ◽  
Yuwei Mao ◽  
Daniel Larsson ◽  
...  

Novel developments in X-ray sources, optics and detectors have significantly advanced the capability of X-ray microscopy at the nanoscale. Depending on the imaging modality and the photon energy, state-of-the-art X-ray microscopes are routinely operated at a spatial resolution of tens of nanometres for hard X-rays or ∼10 nm for soft X-rays. The improvement in spatial resolution, however, has led to challenges in the tomographic reconstruction due to the fact that the imperfections of the mechanical system become clearly detectable in the projection images. Without proper registration of the projection images, a severe point spread function will be introduced into the tomographic reconstructions, causing the reduction of the three-dimensional (3D) spatial resolution as well as the enhancement of image artifacts. Here the development of a method that iteratively performs registration of the experimentally measured projection images to those that are numerically calculated by reprojecting the 3D matrix in the corresponding viewing angles is shown. Multiple algorithms are implemented to conduct the registration, which corrects the translational and/or the rotational errors. A sequence that offers a superior performance is presented and discussed. Going beyond the visual assessment of the reconstruction results, the morphological quantification of a battery electrode particle that has gone through substantial cycling is investigated. The results show that the presented method has led to a better quality tomographic reconstruction, which, subsequently, promotes the fidelity in the quantification of the sample morphology.


2021 ◽  
Vol 11 (22) ◽  
pp. 10549
Author(s):  
Vasileios Panis ◽  
Erwan Donal

Cardiac imaging techniques include a variety of distinct applications with which we can visualize cardiac function non-invasively. Through different applications of physical entities such as sound waves, X-rays, magnetic fields, and nuclear energy, along with highly sophisticated computer hardware and software, it is now possible to reconstruct the dynamic aspect of cardiac function in many forms, from static images to high-definition videos and real-time three-dimensional projections. In this review, we will describe the fundamental principles of the most widely used techniques and, more specifically, which imaging modality and on what occasion we should use them in order to analyze different aspects of cardiac function.


Biomedicines ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 1918
Author(s):  
Katharina S. Keuenhof ◽  
Anoop Kavirayani ◽  
Susanne Reier ◽  
Stefan H. Geyer ◽  
Wolfgang J. Weninger ◽  
...  

High-resolution episcopic microscopy (HREM) is a three-dimensional (3D) episcopic imaging modality based on the acquisition of two-dimensional (2D) images from the cut surface of a block of tissue embedded in resin. Such images, acquired serially through the entire length/depth of the tissue block, are aligned and stacked for 3D reconstruction. HREM has proven to be specifically advantageous when integrated in correlative multimodal imaging (CMI) pipelines. CMI creates a composite and zoomable view of exactly the same specimen and region of interest by (sequentially) correlating two or more modalities. CMI combines complementary modalities to gain holistic structural, functional, and chemical information of the entire sample and place molecular details into their overall spatiotemporal multiscale context. HREM has an advantage over in vivo 3D imaging techniques on account of better histomorphologic resolution while simultaneously providing volume data. HREM also has certain advantages over ex vivo light microscopy modalities. The latter can provide better cellular resolution but usually covers a limited area or volume of tissue, with limited 3D structural context. HREM has predominantly filled a niche in the phenotyping of embryos and characterisation of anatomic developmental abnormalities in various species. Under the umbrella of CMI, when combined with histopathology in a mutually complementary manner, HREM could find wider application in additional nonclinical and translational areas. HREM, being a modified histology technique, could also be incorporated into specialised preclinical pathology workflows. This review will highlight HREM as a versatile imaging platform in CMI approaches and present its benefits and limitations.


2021 ◽  
Vol 1 (3) ◽  
pp. 286-305
Author(s):  
John Moir ◽  
Saira Khanna ◽  
Dimitra Skondra

Diabetes mellitus (DM), a disorder rapidly growing in prevalence, is linked to the retinal microvasculature complication diabetic retinopathy (DR). As one of the leading global causes of vision impairment and loss, imaging techniques to detect and monitor DR must continue to improve in order to address this growing burden. Optical coherence tomography angiography (OCTA) is a nascent imaging modality that generates three-dimensional visualizations of the retinal and choroidal microvasculature. Compared to fluorescein angiography, the gold-standard imaging modality for retinal vessels, OCTA offers the advantages of being non-invasive, quick, and able to resolve the multiple plexuses within the retina. Quantitative OCTA studies have explored parameters such as vessel density (VD), foveal avascular zone (FAZ), acircularity index, vessel tortuosity (VT), and fractal dimension (FD) amongst DR patients. This review synthesizes the main trends emerging from quantitative OCTA-based studies of DR and interrogates them within the context of DR pathophysiology. We offer a glimpse into how analysis techniques have shifted in the years since OCTA came into existence, while speculating on its future role in clinical practice.


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