379 research outputs found

    Imaging cardio-vascular infection

    Get PDF

    Imaging cardio-vascular infection

    Get PDF

    Imaging cardio-vascular infection

    Get PDF

    The clinical application of PET/CT: a contemporary review

    Get PDF
    The combination of positron emission tomography (PET) scanners and x-ray computed tomography (CT) scanners into a single PET/CT scanner has resulted in vast improvements in the diagnosis of disease, particularly in the field of oncology. A decade on from the publication of the details of the first PET/CT scanner, we review the technology and applications of the modality. We examine the design aspects of combining two different imaging types into a single scanner, and the artefacts produced such as attenuation correction, motion and CT truncation artefacts. The article also provides a discussion and literature review of the applications of PET/CT to date, covering detection of tumours, radiotherapy treatment planning, patient management, and applications external to the field of oncology

    Data and knowledge engineering for medical image and sensor data

    Get PDF

    Fusion and Analysis of Multidimensional Medical Image Data

    Get PDF
    Analýza medicínských obrazů je předmětem základního výzkumu již řadu let. Za tu dobu bylo v této oblasti publikováno mnoho výzkumných prací zabývajících se dílčími částmi jako je rekonstrukce obrazů, restaurace, segmentace, klasifikace, registrace (lícování) a fúze. Kromě obecného úvodu, pojednává tato disertační práce o dvou medicínsky orientovaných tématech, jež byla formulována ve spolupráci s Philips Netherland BV, divizí Philips Healthcare. První téma je zaměřeno na oblast zpracování obrazů subtrakční angiografie dolních končetin člověka získaných pomocí výpočetní X-Ray tomografie (CT). Subtrakční angiografie je obvykle využívaná při podezření na periferní cévní onemocnění (PAOD) nebo při akutním poškození dolních končetin jako jsou fraktury apod. Současné komerční metody nejsou dostatečně spolehlivé už v předzpracování, jako je například odstranění pacientského stolu, pokrývky, dlahy, apod. Spolehlivost a přesnost identifikace cév v subtrahovaných datech vedoucích v blízkosti kostí je v důsledku Partial Volume artefaktu rovněž nízká. Automatické odstranění kalcifikací nebo detekce malých cév doplňujících nezbytnou informaci o náhradním zásobení dolních končetin krví v případě přerušení hlavních zásobujících cév v současné době rovněž nesplňují kritéria pro plně automatické zpracování. Proto hlavním cílem týkající se tohoto tématu bylo vyvinout automatický systém, který by mohl současné nedostatky v CTSA vyšetření odstranit. Druhé téma je orientováno na identifikaci patologických změn na páteři člověka v CT obrazech se zaměřením na osteolytické a osteoblastické léze u jednotlivých obratlů. Tyto změny obvykle nastávají v důsledků postižení metastazujícím procesem rakovinového onemocnění. Pro detekci patologických změn je pak potřeba identifikace a segmentace jednotlivých obratlů. Přesnost analýzy jednotlivých lézí však závisí rovněž na správné identifikaci těla a zadních segmentů u jednotlivých obratlů a na segmentaci trabekulárního centra obratlů, tj. odstranění kortikální kosti. Během léčby mohou být pacienti skenováni vícekrát, obvykle s několika-mesíčním odstupem. Hodnocení případného vývoje již detekovaných patologických změn pak logicky vychází ze správné detekce patologií v jednotlivých obratlech korespondujících si v jednotlivých akvizicích. Jelikož jsou příslušné obratle v jednotlivých akvizicích obvykle na různé pozici, jejich fúze, vedoucí k analýze časového vývoje detekovaných patologií, je komplikovaná. Požadovaným výsledkem v tomto tématu je vytvoření komplexního systému pro detekci patologických změn v páteři, především osteoblastických a osteolytických lézí. Takový systém tedy musí umožnovat jak segmentaci jednotlivých obratlů, jejich automatické rozdělení na hlavní části a odstranění kortikální kosti, tak také detekci patologických změn a jejich hodnocení. Ačkoliv je tato disertační práce v obou výše zmíněných tématech primárně zaměřena na experimentální část zpracování medicínských obrazů, zabývá se všemi nezbytnými kroky, jako je předzpracování, registrace, dodatečné zpracování a hodnocení výsledků, vedoucími k možné aplikovatelnosti obou systému v klinické praxi. Jelikož oba systémy byly řešeny v rámci týmové spolupráce jako celek, u obou témat jsou pro některé konkrétní kroky uvedeny odkazy na doktorskou práci Miloše Malínského.Analysis of medical images has been subject of basic research for many years. Many research papers have been published in the field related to image analysis and focused on partial aspects such as reconstruction, restoration, segmentation and classification, registration (spatial alignment) and fusion. Besides the introduction of related general concepts used in medical image processing, this thesis deals with two specific medical problems formulated in cooperation with Philips Netherland BV, Philips Healthcare division. The first topic is focused on subtraction angiography in patients’ lower legs utilizing image data from X-Ray computed tomography (CT). CT subtraction angiography (CTSA) is typically used for indication of the Peripheral Artery Occlusive Disease (PAOD) and for examination of acute injuries of lower legs such as acute fractures, etc. Current methods in clinical praxis are not sufficient regarding the pre-processing such as masking of patient desk, cover, splint, etc. The subtraction of blood vessels adjacent to neighboring bones in lower legs is of low accuracy due to the Partial Volume artifact. Masking of calcifications and detection of tiny blood vessels complementing necessary information about the alternative blood supply in lower legs in case of obstruction in main arteries is also not reliable for fully automated process presently. Therefore, the main aim regarding this topic was to develop an automated framework that could overcome current shortcomings in CTSA examination. The second topic is oriented on the identification and evaluation of pathologic changes in human spine, focusing on osteolytic and osteoblastic lesions in individual vertebrae in CT images. Such changes occur typically as a consequence of metastasizing process of cancerous disease. For the detection of pathologic changes, an identification and segmentation of individual vertebrae is necessary. Moreover, the analysis of individual lesions in vertebrae depends also on correct identification of vertebral body and posterior segments of each vertebra, and on segmentation of their trabecular centers. Patients are typically examined more than once during their therapy. Then, the evaluation of possible tumorous progression is based on accurate detection of pathologies in individual vertebrae in the base-line and corresponding follow-up images. Since the corresponding vertebrae are in mutually different positions in the follow-up images, their fusion leading to the analysis of the lesion progression is complicated. The main aim regarding this topic is to develop a complex framework for detection of pathologic lesions on spine, with the main focus on osteoblastic and osteolystic lesions. Such system has to provide not only reliable segmentation of individual vertebrae and detection of their main regions but also the masking of their cortical bone, detection of their pathologic changes and their evaluation. Although this dissertation thesis is primarily oriented at the experimental part of medical image processing considering both the above mentioned topics, it deals with all necessary processing steps, i.e. preprocessing, image registration, post-processing and evaluation of results, leading to the future use of both frameworks in clinical practice. Since both frameworks were developed in a team, there are some chapters referring to the dissertation thesis of Milos Malinsky.

    CT Scanning

    Get PDF
    Since its introduction in 1972, X-ray computed tomography (CT) has evolved into an essential diagnostic imaging tool for a continually increasing variety of clinical applications. The goal of this book was not simply to summarize currently available CT imaging techniques but also to provide clinical perspectives, advances in hybrid technologies, new applications other than medicine and an outlook on future developments. Major experts in this growing field contributed to this book, which is geared to radiologists, orthopedic surgeons, engineers, and clinical and basic researchers. We believe that CT scanning is an effective and essential tools in treatment planning, basic understanding of physiology, and and tackling the ever-increasing challenge of diagnosis in our society

    Multiclass Bone Segmentation of PET/CT Scans for Automatic SUV Extraction

    Get PDF
    In this thesis I present an automated framework for segmentation of bone structures from dual modality PET/CT scans and further extraction of SUV measurements. The first stage of this framework consists of a variant of the 3D U-Net architecture for segmentation of three bone structures: vertebral body, pelvis, and sternum. The dataset for this model consists of annotated slices from the CT scans retrieved from the study of post-HCST patients and the 18F-FLT radiotracer, which are undersampled volumes due to the low-dose radiation used during the scanning. The mean Dice scores obtained by the proposed model are 0.9162, 0.9163, and 0.8721 for the vertebral body, pelvis, and sternum class respectively. The next step of the proposed framework consists of identifying the individual vertebrae, which is a particularly difficult task due to the low resolution of the CT scans in the axial dimension. To address this issue, I present an iterative algorithm for instance segmentation of vertebral bodies, based on anatomical priors of the spine for detecting the starting point of a vertebra. The spatial information contained in the CT and PET scans is used to translate the resulting masks to the PET image space and extract SUV measurements. I then present a CNN model based on the DenseNet architecture that, for the first time, classifies the spatial distribution of SUV within the marrow cavities of the vertebral bodies as normal engraftment or possible relapse. With an AUC of 0.931 and an accuracy of 92% obtained on real patient data, this method shows good potential as a future automated tool to assist in monitoring the recovery process of HSCT patients

    Interplay between spinal cord and cerebral cortex metabolism in amyotrophic lateral sclerosis

    Get PDF
    Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder, characterized by a degeneration of upper and lower motor neurons leading to a progressive muscular paralysis. Although median survival most often averages 3\u20134 years, the large variability of its course (Calvo et al., 2017) raises an urgent need to develop biomarkers able to characterize the mechanisms underlying disease progression and to improve the diagnostic yield of clinical and neuro-physiological evaluation. Most studies in this setting focused on cortical response to ALS. Among these approaches, brain PET studies with 18F-\ufb02uorodeoxyglucose (FDG) already reported a signi\ufb01cant reduction in glucose metabolism (Pagani et al., 2014) in motor and premotor cortex (Kiernan et al., 1994; Abrahams et al., 1996, 2005). By contrast, involvement of the spinal cord has been characterized in relatively lower detail, mostly because of the anatomical features of this structure that limit the standardization of its evaluation. Consequently, a large uncertainty still exists about the mechanisms underlying ALS-induced damage in the spinal cord and its relationship with cortical impairment. We recently reported the potential of the Hough transform in delineating spinal cord structure and metabolic activity in a population of ALS patients subjected to FDG PET/CT (Marini et al., 2016). Speci\ufb01cally, this classical pattern recognition approach for the automatic identi\ufb01cation of straight lines in the image has been recently extended to the recognition of more complex shapes. This computational 3D approach enabled the extraction of spinal cord metabolic information from whole body images and per- mitted us to document increased glucose consumption, possibly representing a potential and independent prognostic marker (Marini et al., 2016). In the present study, we simultaneously analysed brain and spinal cord FDG uptake in a series of prospectively recruited patients submitted to brain and wholebody PET/CT
    corecore