MRI and CT Fusion in Stereotactic Electroencephalography (SEEG).

Epilepsy is a neurological disorder characterized by spontaneous recurrent seizures. While 20% to 30% of epilepsy cases are untreatable with Anti-Epileptic Drugs, some of these cases can be addressed through surgical intervention. The success of such interventions greatly depends on accurately locating the epileptogenic tissue, a task achieved using diagnostic techniques like Stereotactic Electroencephalography (SEEG). SEEG utilizes multi-modal fusion to aid in electrode localization, using pre-surgical resonance and post-surgical computer tomography images as inputs. To ensure the absence of artifacts or misregistrations in the resultant images, a fusion method that accounts for electrode presence is required. We proposed an image fusion method in SEEG that incorporates electrode segmentation from computed tomography as a sampling mask during registration to address the fusion problem in SEEG. The method was validated using eight image pairs from the Retrospective Image Registration Evaluation Project (RIRE). After establishing a reference registration for the MRI and identifying eight points, we assessed the method's efficacy by comparing the Euclidean distances between these reference points and those derived using registration with a sampling mask. The results showed that the proposed method yielded a similar average error to the registration without a sampling mask, but reduced the dispersion of the error, with a standard deviation of 0.86 when a mask was used and 5.25 when no mask was used.

Proceso para la fusión de neuroimágenes de Tomografía por Emisión de Positrones y Resonancia Magnética / Process for the fusion of Positron Emission Tomography and Magnetic Resonance neuroimaging

En radiología se utilizan varias técnicas imagenológicas para el diagnóstico de enfermedades y la asistencia en intervenciones quirúrgicas con el objetivo de determinar la ubicación y dimensión exacta de un tumor cerebral. Técnicas como la Tomografía por Emisión de Positrones y la Resonancia Magnética permiten determinar la naturaleza maligna o benigna de un tumor cerebral y estudiar las estructuras del cerebro con neuroimágenes de alta resolución. Investigadores a nivel internacional han utilizado diferentes técnicas para la fusión de la Tomografía por Emisión de Positrones y Resonancia Magnética al permitir la observación de las características fisiológicas en correlación con las estructuras anatómicas. La presente investigación tiene como objetivo elaborar un proceso para la fusión de neuroimágenes de Tomografía por Emisión de Positrones y Resonancia Magnética. Para ello se definieron 5 actividades en el proceso y los algoritmos a utilizar en cada una, lo cual propició identificar los más eficientes para aumentar la calidad en el proceso de fusión. Como resultado se obtuvo un proceso de fusión de neuroimágenes basado en un esquema híbrido Wavelet y Curvelet que garantiza obtener imágenes fusionadas de alta calidad(AU)

In radiology, various imaging techniques are used for the diagnosis of diseases and assistance in surgical interventions with the aim of determining the exact location and dimension of a brain tumor. Techniques such as Positron Emission Tomography and Magnetic Resonance can determine the malignant or benign nature of a brain tumor and study brain structures with high-resolution neuroimaging. International researchers have used different techniques for the fusion of Positron Emission Tomography and Magnetic Resonance, allowing the observation of physiological characteristics in correlation with anatomical structures. The present research aims to develop a process for the fusion of neuroimaging of Positron Emission Tomography and Magnetic Resonance Imaging. Five activities were defined in the process and the algorithms to be used in each one, which led identifying the most efficient ones to increase the quality in the fusion process. As a result, a neuroimaging fusion process was obtained based on a hybrid Wavelet and Curvelet scheme that guarantees high quality merged images(AU)

Nuevas tecnologías de imágenes para el diagnóstico y tratamiento de los aneurismas de aorta complejos / New Imaging Technologies for the Diagnosis and Treatment of Complex Aortic Aneurysms

RESUMEN La tecnología en imágenes desempeña un papel fundamental como guía en el tratamiento endovascular del aneurisma de aorta, especialmente en la aorta compleja toracoabdominal. Las salas quirúrgicas combinan imágenes de alta calidad con un entorno estéril y funcional, lo que permite, además de mejores resultados, una reducción del contraste a utilizar y la exposición a la radiación de pacientes y operadores. Esta presentación tiene como objetivo describir el uso actual de dicha tecnología, combinando angiotomografía y tomografía computarizada de haz cónico intraoperatoria, la "fusión"de imágenes y la ecografía intravascular, para guiar procedimientos y así mejorar la tasa de éxito intraoperatorio y reducir la necesidad de reintervenciones. Por otro lado, se describe un procedimiento para crear plantillas personalizadas 3D con las imágenes de alta definición de la anatomía arterial del paciente, que sirven como guías específicas para confeccionar en quirófano endoprótesis fenestradas. Estas plantillas de fenestración personalizadas podrían ampliar el número de pacientes con aneurismas complejos tratados en forma mínimamente invasiva.

ABSTRACT Imaging technology plays a key guiding role in the endovascular treatment of aortic aneurysms, especially in the complex thoracoabdominal aorta. The operating rooms combine high quality imaging with a sterile and functional environment, allowing for better outcomes, a reduction of the contrast agent to be used and of patients' and operators' exposure to radiation. The aim of this presentation is to describe the current use of imaging technology, combining intraoperative cone beam computed tomography (CBCT) and computed tomography angiography (CTA), image "fusion" and intravascular ultrasound, to guide the procedures and improve the intraoperative success rate, and to reduce the need for reinterventions. Furthermore, a procedure to create custom 3D templates with high definition images of the patient's arterial anatomy is described, which serve as specific guides for making fenestrated stent-grafts in the operating room. These custom fenestration templates could increase the number of patients with complex aneurysms treated with a minimally invasive approach.

Análisis y selección de técnicas para la fusión de imágenes PET/CT basado en software / Analysis and selection of techniques for the fusion of PET/CT imaging based on software

Técnicas como la Tomografía por Emisión de Positrones y la Tomografía Computarizada permiten determinar la naturaleza maligna o benigna de un tumor y estudiar las estructuras anatómicas del cuerpo con imágenes de alta resolución, respectivamente. Investigadores a nivel internacional han utilizado diferentes técnicas para la fusión de la Tomografía por Emisión de Positrones y la Tomografía Computarizada porque permite observar las funciones metabólicas en correlación con las estructuras anatómicas. La presente investigación se propone realizar un análisis y selección de algoritmos que propicien la fusión de neuroimágenes, basado en la precisión de los mismos. De esta forma contribuir al desarrollo de software para la fusión sin necesidad de adquirir los costosos equipos de adquisición de imágenes de alto rendimiento, los cuales son costosos. Para el estudio se aplicaron los métodos Análisis documental, Histórico lógico e Inductivo deductivo. Se analizaron e identificaron las mejores variantes de algoritmos y técnicas para la fusión según la literatura reportada. A partir del análisis de estas técnicas se identifica como mejor variante el esquema de fusión basado en Wavelet para la fusión de las imágenes. Para el corregistro se propone la interpolación Bicúbica. Como transformada discreta de Wavelet se evidencia el uso de la de Haar. Además, la investigación propició desarrollar el esquema de fusión basado en las técnicas anteriores. A partir del análisis realizado se constataron las aplicaciones y utilidad de las técnicas de fusión como sustitución a los altos costos de adquisición de escáneres multifunción PET/CT para Cuba(AU)

Techniques such as Positron Emission Tomography and Computed Tomography allow to determine the malignant or benign nature of a tumor and to study the anatomical structures of the body with high resolution images, respectively. International researchers have used different techniques for the fusion of Positron Emission Tomography and Computed Tomography because it allows observing metabolic functions in correlation with anatomical structures. The present investigation proposes to carry out an analysis and selection of algorithms that favor the fusion of neuroimaging, based on their precision. In this way, contribute to the development of fusion software without the need to purchase expensive high-performance imaging equipment, which is expensive. For the study the documentary analysis, logical historical and deductive inductive methods were applied. The best algorithm variants and techniques for fusion were analyzed and identified according to the reported literature. From the analysis of these techniques, the Wavelet-based fusion scheme for image fusion is identified as the best variant. Bicubic interpolation is proposed for co-registration. As a discrete Wavelet transform, the use of Haar's is evidenced. In addition, the research led to the development of the fusion scheme based on the previous techniques. From the analysis carried out, the applications and usefulness of fusion techniques were verified as a substitute for the high costs of acquiring PET / CT multifunction scanners for Cuba(AU)

Dataset of thermal and visible aerial images for multi-modal and multi-spectral image registration and fusion.

This article presents a dataset of thermal and visible aerial images of the same flat scene at Melendez campus of Universidad del Valle, Cali, Colombia. The images were acquired using an UAV equipped with either a thermal or a visible camera. The dataset is useful for testing techniques for the improvement, registration and fusion of multi-modal and multi-spectral images. The dataset consists of 30 visible images and their metadata, 80 thermal images and their metadata, and a visible georeferenced orthoimage. The metadata related to every image contains the WGS84 coordinates for allocating the images. Also, the homography matrices between every image and the orthoimage are included in the dataset. The images and homographies are compatible with the well-known assessment protocol for detection and description proposed by Mikolajczyk and Schmid [1].

Spatial Compounding of 3-D Fetal Brain Ultrasound Using Probabilistic Maps.

A new method to address the problem of shadowing in fetal brain ultrasound volumes is presented. The proposed approach is based on the spatial composition of multiple 3-D fetal head projections using the weighted Euclidean norm as an operator. A support vector machine, which is trained with optimal textural features, was used to assign weighting according to the posterior probabilities of brain tissue and shadows. Both phantom and real fetal head ultrasound volumes were compounded using previously reported operators and compared with the proposed composition method to validate it. The quantitative evaluations revealed increases in signal-to-noise ratio ≤35% and in contrast-to-noise ratio ≤135% using real data. Qualitative comparisons made by obstetricians indicated that this novel method adequately recovers brain tissue and improves the visibility of the main cerebral structures. This may prove useful both for fetal monitoring and in the diagnosis of brain defects. Overall this new approach outperforms spatial composition methods previously reported.

Wavelet-Based Visible and Infrared Image Fusion: A Comparative Study.

This paper evaluates different wavelet-based cross-spectral image fusion strategies adopted to merge visible and infrared images. The objective is to find the best setup independently of the evaluation metric used to measure the performance. Quantitative performance results are obtained with state of the art approaches together with adaptations proposed in the current work. The options evaluated in the current work result from the combination of different setups in the wavelet image decomposition stage together with different fusion strategies for the final merging stage that generates the resulting representation. Most of the approaches evaluate results according to the application for which they are intended for. Sometimes a human observer is selected to judge the quality of the obtained results. In the current work, quantitative values are considered in order to find correlations between setups and performance of obtained results; these correlations can be used to define a criteria for selecting the best fusion strategy for a given pair of cross-spectral images. The whole procedure is evaluated with a large set of correctly registered visible and infrared image pairs, including both Near InfraRed (NIR) and Long Wave InfraRed (LWIR).

Presentación atípica de una metástasis ósea del pulmón / Présentation atypique d'une métastase osseuse de poumon / Unusual occurrence of osseous metastasis of the lung

Se presenta un paciente masculino de 49 años con antecedentes de Neoplasia de pulmón el cual acude por dolor y aumento de volumen en el miembro inferior izquierdo. Los estudios imaginológicos (radiografías, tomografía computarizada, gammagrafía) sugerían una miositis osificante del tercio medio de la diáfisis femoral izquierda, debido al compromiso de partes blandas, ya que es poco frecuente visualizarlo como una metástasis, pero el diagnóstico histopatológico fue el de una lesión metastásica(AU)

Here is the case of a 49 years-old male patient with a history of lung neoplasia that went to the doctor's because of pain and inflammation of his left leg. Imaging studies including X-rays, CT and scintigraphy indicated ossifying myositis in the medial third of the left femoral diaphysis due to compromised soft tissues, but the histopathological diagnosis showed a metastatic injure(AU)

Un patient âgé de 49 ans, avec des antécédents de néoplasie de poumon, est vu en consultation due à une douleur et à un grossissement du membre inférieur gauche. L'imagerie (radiographie, tomographie axiale informatisée, scintigraphie) a suggéré une myosite ossifiante au niveau du tiers moyen de la diaphyse fémorale gauche due à une lésion des parties molles. Puisque la métastase est difficile à distinguer, un test histologique a confirmé la lésion métastatique(AU)

Planificación neuroquirúrgica con software osirix. presentación de 3 casos y descripción de la técnica utilizada / Neurosurgical planning with osirix software. presentation of 3 cases and description of the technique used

Objetivo: conocer la individualidad anatómica es clave para reducir el trauma quirúrgico y obtener un mejor resultado. Actualmente, el avance en las neuroimágenes ha objetivado esa individualidad anatómica, permitiendo planificar la intervención quirúrgica. Con este objetivo, presentamos nuestra experiencia con el software Osirix. Descripción de la técnica: se presentan 3 casos ejemplificadores. Caso 1: paciente con meningioma de la convexidad parasagital izquierda en área premotora; Caso 2: paciente con macroadenoma hipofisario, operada previamente por vía transeptoesfenoidal en otra institución con una resección parcial; Caso 3: paciente con lesiones bilaterales en pedúnculos cerebelosos medios. Se realizó la planificación prequirúrgica con el software OsiriX, fusionando y reconstruyendo en 3D las imágenes de TC e IRM, para analizar relaciones anatómicas, medir distancias, coordenadas y trayectorias, entre otras funciones. Discusión: el software OsiriX de acceso libre y gratuito permite al cirujano, mediante la fusión y reconstrucción en 3D de imágenes, analizar la anatomía individual del paciente y planificar de forma rápida, simple, segura y económica cirugías de alta complejidad. En el Caso 1 se pudieron analizar las relaciones del tumor con las estructuras adyacentes para minimizar el abordaje. En el Caso 2, el software permitió comprender la anatomía post-operatoria previa del paciente, para determinar la trayectoria del abordaje transnasal endoscópico y la necesidad de ampliar su exposición, logrando la resección tumoral completa. En el Caso 3 permitió obtener las coordenadas estereotáxicas y trayectoria de una lesión sin representación tomográfica. Conclusión: en caso de no contar con costosos sistemas de neuronavegación o estereotáxia, el software OsiriX es una alternativa a la hora de planificar la cirugía, con el objetivo de disminuir el trauma y la morbilidad operatorias.

Introduction: understanding of the anatomical individuality is key to reduce surgical trauma and obtain a better outcome. Nowadays, advances in neuroimages allows to analyze this anatomical individuality and so planning surgery. With this objective, we present our experience with the OsiriX software. Technical description: we present three different applications as examples. Case 1: patient with a premotor cortex convexity parasagittal meningioma; Case 2: patient with a nonfunctioning pituitary macroadenoma operated on 2 years ago in another institution, with partial resection by transsphenoidal approach; Case 3: patient with bilateral middle cerebellar peduncles lesions. OsiriX Software was used for surgical planning. Volumetric CT and MRI images were fused and 3D reconstruction images obtained, to analyze anatomical relationships, measure distances, coordinates and trajectories, among other features.Discussion: OsiriX software is a useful, open-source and free software tool that provides surgeons with valuable informations. It allows to study individual patient’s anatomy and plan a surgical approach in a fast, simple, economic and safe way. In Case 1 the software let us analyze the relationship of the tumor with the surrounding structures in order to minimize the approach’s morbidity. In Case 2, to understand the unique anatomic characteristics of an previously operated patient giving us important information regarding pathways and need for extra bone removal, achieving a complete tumor resection by an endoscopic transnasal approach. In Case 3, allowed us to obtain the stereotactic coordinates and trajectory for a not visualizable CT scan lesion.Conclusion: when expensive neuronavigation systems are not available, OsiriX is an alternative for neurosurgical planning, with the aim of reducing trauma and surgical morbidity.

Fusão 3D de imagens de MRI/CT e termografia / 3D image fusion using MRI/CT and infrared images

INTRODUÇÃO: A termografia por imagem infravermelha (IR) é uma técnica para diagnóstico não-invasiva que permite a avaliação e quantificação de variações de temperatura na superfície da pele. Apesar de fornecer informações significativas para auxiliar no diagnóstico médico, esta técnica não permite avaliar det alhes anatômicos da região sendo analisada. Este artigo apresenta uma nova metodologia para realizar a fusão entre diferentes modalidades de imagens, tais como ressonância magnética (MRI) ou tomografia computadorizada por raios X (CT), juntamente com imagens de termografia infravermelha. MÉTODOS: Para a construção do modelo 3D, primeiramente são adquiridas as imagens por ressonância magnética (MRI) ou tomografia computadorizada (CT) e um conjunto de imagens térmicas da região de interesse. Em seguida, realiza-se o registro utilizando as projeções 2D (dos planos tomográficos) com as imagens térmicas. Após o registro, as imagens térmicas são combinadas e projetadas sobre o modelo 3D das imagens de MRI ou CT. RESULTADOS: O resultado é uma imagem 3D que combina informação de duas modalidades de imagens médicas diferentes. A combinação dessas duas modalidades de imagens médicas disponibiliza uma nova técnica de imagem 3D que agrupa informações anatômicas (MRI ou CT) e funcionais (variações de temperatura na superfície do corpo). CONCLUSÃO: Os resultados obtidos até o momento com essa nova metodologia indicam que ela pode auxiliar em diagnósticos médicos.

INTRODUCTION: Infrared (IR) thermal imaging is a non-invasive and diagnostic technique that allows evaluation and quantification based on the temperature changes of the skin surface. It provides significant information for clinical diagnosis; however this technique does not present the anatomical details of the region under inspection. In this work, it is presented an innovative image fusion method between different imaging modalities, such as magnetic resonance images (MRI) or X-ray computed tomography (CT), together with IR thermal images. METHODS: Firstly, in order to build the 3D model, the MRI or CT images and the IR thermal images (from the region of interest) are acquired. Then, based on the tomographic planes (image slices), the 2D projections are generated, and the IR images are registered accordingly. Next, the already registered IR set of images are combined and projected over the 3D MRI or CT model. RESULTS: The result is a 3D fused image that combines the information contents from the two different medical imaging modalities. The combination of these two medical imaging modalities offers a new 3D imaging technique that combines anatomical (MRI or CT) and functional (the body's surface temperature) information. CONCLUSION: The results obtained up to now with this new methodology indicate that it can aid in medical diagnosis.