Slikovno diagnosticiranje je pomembno pri odkrivanju in opredelitvi prirojenih nepravilnosti sečil, na katere posumimo že v sklopu prenatalnega diagnosticiranja, takoj po rojstvu ali kasneje v ...življenju. Slikovno diagnosticiranje pomaga tudi pri določanju tveganja kronične ledvične bolezni v otroštvu, saj je potrebno spremljanje otrok, da zmanjšamo oziroma odložimo razvoj kronične ledvične bolezni.
Gliomi so najpogostejši primarni možganski tumorji. Po novih smernicah jih razlikujemo na podlagi molekularnih markerjev, kar daje pomembno podlago za razvoj zdravljenja po meri bolnika. Tipizacija ...tumorjev je lahko invazivna s pomočjo biopsije in neinvazivna. Slednja v zadnjem času pridobiva veliko vlogo zaradi razvoja radiogenomike, ki proučuje povezavo med slikovnimi fenotipi tumorjev in genomiko. Magnetnoresonančna ocena tumorjev, pri kateri uporabljamo številne standardne in funkcionalne sekvence, omogoča neinvazivno tipizacijo tumorjev glede na specifične morfološke značilnosti posameznih vrst tumorjev s posameznimi molekularnimi markerji. Po pregledu obstoječe literature so avtorji v članku opisali slikovne značilnosti treh tumorskih genotipov, in sicer mutacije izocitratne dehidrogenaze, kodelecije 1p19q in metilacije promotorja metilgvanin metiltansferaze. Kljub hitremu razvoju radiogenomike primanjkuje obširnih študij z dovolj velikimi in standardiziranimi vzorci bolnikov, ki bi podale zanesljivejše rezultate.
Prikazujemo primer bolnice, ki je bila zaradi raka dojke obojestransko operirana. V drugem primeru je šlo za invazivni lobularni karcinom (ILC). Pri bolnici smo pred operacijo opravili preiskavo dojk ...z magnetno resonanco (MR), ki je pokazala večji obseg bolezni od pričakovanega. Pri bolnicah z ILC predoperativna preiskava z MR pri 28 % spremeni načrtovano operacijo. Preiskavo dojk z MR opravljamo tudi za odkrivanje karcinomov v predelih dojk, kjer mamografija in UZ sprememb ne pojasnita povsem, za odkrivanje primarnega tumorja ob pozitivnih pazdušnih bezgavkah, za oceno odgovora na kemoterapijo, za odkrivanje ruptur pri silikonskih vsadkih in za iskanje prostih silikonskih delcev ob rupturi. MR-preiskava dojk se uporablja tudi kot ena od presejalnih metod za odkrivanje raka dojk pri ženskah s povečanim tveganjem.
Protein NMR Spectroscopy Cavanagh, John; Skelton, Nicholas J; Fairbrother, Wayne J ...
2006, 2010-07-21
eBook
Protein NMR Spectroscopy combines a comprehensive theoretical treatment of NMR spectroscopy with an extensive exposition of the experimental techniques applicable to proteins and other biological ...macromolecules in solution. Beginning with simple theoretical models and experimental techniques, Protein NMR Spectroscopy develops the complete repertoire of theoretical principles and experimental techniques necessary for understanding and implementing the most sophisticated NMR experiments.Important new techniques and applications of NMR spectroscopy have emerged since the first edition of this extremely successful book was published in 1996. The second edition includes new sections describing measurement and use of residual dipolar coupling constants for structure determination, TROSY and deuterium labeling for application to large macromolecules, and experimental techniques for characterizing conformational dynamics. In addition, the treatments of instrumentation and signal acquisition, field gradients, multidimensional spectroscopy, and structure calculation are updated and enhanced. Protein NMR Spectroscopy is written as a graduate-level textbook and will be of interest to biochemists, chemists, biophysicists, and structural biologists who utilize NMR spectroscopy or who wish to understand the latest developments in this field.
· Provides an understanding of the theoretical principles important for biological NMR spectroscopy· Demonstrates how to implement, optimize and troubleshoot modern multi-dimensional NMR experiments· Allows for the capability of designing effective experimental protocols for investigations of protein structures and dynamics· Includes a comprehensive set of example NMR spectra of ubiquitin provides a reference for validation of experimental methods
Fifty patients with proven multiple myeloma (MM) underwent magnetic resonance (MR) examination of entire spine in sagittal view using T1-weighted image (T1), T2-weighted image (T2), and T2-weighted ...gradient echo (GE). In 18 patients, the myelomatous foci were hyperintensive in GE and T2 and hypointensive in T1. They corresponded with osteolytic lesions in computed tomography (CT) scan. In another 16 patients with MM, the hyperintensive vertebral foci demonstrated by GE, corresponded with unhomogenic pattern of the vertebral bone marrow in T1 and T2, and insignificant computed tomography (CT) scan. Needle biopsy confirmed histologically the diagnosis MM of involved vertebra in all of them. The vertebral bone marrow had lower signal intensity in GE, which ensured a good contrast between the myelomata and the uninvolved bone marrow. Practically GE enabled the radiologic diagnosis of the spine in 16 patients. It also can prevent a diagnostic pitfall when a fatty focus is suspicious for myeloma in T2 and its demonstration in T1 is poor. Fatty foci were demonstrated in a control group, which included 20 elderly patients who had no history of malignancy. The fatty foci had lower signal intensity in GE and different from the hyperintensive myelomata. Gadolinium diethylene triamine pentaocetic acid (Gd-DTPA) which was administered intravenously in three patients with spinal MM offered no advantage and obscured the lesions.
Zadnjih godina mnoge grupe turista različita kova kucaju na samostanska vrata sa željom da se informiraju i razgovaraju o samostanskom životu. Iz kojih razloga? Vodi li ih znatiželja, želja da ...kritiziraju, ili da nešto novo nauče? Događa se to možda zato što ih progoni tjeskoba?
Despite their wide-spread use, only limited information is available on the comparative test-retest reliability of task-based functional and resting state magnetic resonance imaging measures of blood ...oxygen level dependence (tb-fMRI and rs-fMRI) and cerebral blood flow (CBF) using arterial spin labeling. This information is critical to designing properly powered longitudinal studies. Here we comprehensively quantified and compared the test-retest reliability and reproducibility performance of 8 commonly applied fMRI tasks, 6 rs-fMRI metrics and CBF in 30 healthy volunteers. We find large variability in test-retest reliability performance across the different tb-fMRI paradigms and rs-fMRI metrics, ranging from poor to excellent. A larger extent of activation in tb-fMRI is linked to higher between-subject reliability of the respective task suggesting that differences in the amount of activation may be used as a first reliability estimate of novel tb-fMRI paradigms. For rs-fMRI, a good reliability of local activity estimates is paralleled by poor performance of global connectivity metrics. Evaluated CBF measures provide in general a good to excellent test-reliability matching or surpassing the best performing tb-fMRI and rs-fMRI metrics. This comprehensive effort allows for direct comparisons of test-retest reliability between the evaluated MRI domains and measures to aid the design of future tb-fMRI, rs-fMRI and CBF studies.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Compressed sensing magnetic resonance imaging (CS-MRI) enables fast acquisition, which is highly desirable for numerous clinical applications. This can not only reduce the scanning cost and ease ...patient burden, but also potentially reduce motion artefacts and the effect of contrast washout, thus yielding better image quality. Different from parallel imaging-based fast MRI, which utilizes multiple coils to simultaneously receive MR signals, CS-MRI breaks the Nyquist-Shannon sampling barrier to reconstruct MRI images with much less required raw data. This paper provides a deep learning-based strategy for reconstruction of CS-MRI, and bridges a substantial gap between conventional non-learning methods working only on data from a single image, and prior knowledge from large training data sets. In particular, a novel conditional Generative Adversarial Networks-based model (DAGAN)-based model is proposed to reconstruct CS-MRI. In our DAGAN architecture, we have designed a refinement learning method to stabilize our U-Net based generator, which provides an end-to-end network to reduce aliasing artefacts. To better preserve texture and edges in the reconstruction, we have coupled the adversarial loss with an innovative content loss. In addition, we incorporate frequency-domain information to enforce similarity in both the image and frequency domains. We have performed comprehensive comparison studies with both conventional CS-MRI reconstruction methods and newly investigated deep learning approaches. Compared with these methods, our DAGAN method provides superior reconstruction with preserved perceptual image details. Furthermore, each image is reconstructed in about 5 ms, which is suitable for real-time processing.
Resting-state functional magnetic resonance imaging (rfMRI) allows one to study functional connectivity in the brain by acquiring fMRI data while subjects lie inactive in the MRI scanner, and taking ...advantage of the fact that functionally related brain regions spontaneously co-activate. rfMRI is one of the two primary data modalities being acquired for the Human Connectome Project (the other being diffusion MRI). A key objective is to generate a detailed in vivo mapping of functional connectivity in a large cohort of healthy adults (over 1000 subjects), and to make these datasets freely available for use by the neuroimaging community. In each subject we acquire a total of 1h of whole-brain rfMRI data at 3T, with a spatial resolution of 2×2×2mm and a temporal resolution of 0.7s, capitalizing on recent developments in slice-accelerated echo-planar imaging. We will also scan a subset of the cohort at higher field strength and resolution. In this paper we outline the work behind, and rationale for, decisions taken regarding the rfMRI data acquisition protocol and pre-processing pipelines, and present some initial results showing data quality and example functional connectivity analyses.
•The Human Connectome Project is mapping brain connectivity in vivo in detail.•Resting-state fMRI (rfMRI) is a major modality in the Human Connectome Project.•We describe rfMRI acquisition and analysis protocols for the HCP.
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