Temat: tomography - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Comparing methods of image reconstruction in electrical impedance tomography
Autorzy:: Rymarczyk, T.
Filipowicz, S.F.
Sikora, J.
Tematy:: impedance tomography
electrical impedance tomography
EIT; Pokaż więcej
Wydawca:: Politechnika Poznańska. Wydawnictwo Politechniki Poznańskiej
Powiązania:: https://bibliotekanauki.pl/articles/97630.pdf Link otwiera się w nowym oknie
Opis:: The problem of the image reconstruction in Electrical Impedance Tomography (EIT) is a highly ill-posed inverse problem. There are mainly two categories of image reconstruction algorithms, the direct algorithm and the iterative algorithm which was used in this publication. This paper presents the applications of the level set function for identification the unknown shape of an interface motivated by Electrical Impedance Tomography (EIT) by using a several level set algorithms. The conductivity values in different regions are determined by the finite element method. The applications were based on the level set method, the variational level set algorithm and the Mumford-Shah algorithm to solve the inverse problem.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Comparison of volumetric reconstructions obtained from CT and micro-CT scans of the petrous bone
Autorzy:: Brzegowy, Paweł
Skrzat, Janusz
Walocha, Jerzy
Spulber, Alexandru
Wroński, Sebastian
Tarasiuk, Jacek
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

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Skocz do pozycji: 3.

Tytuł:: The Role of FDG Positron Emission Tomography/Contrast--Enhanced Computed Tomography in Preoperative Staging and Postoperative Follow-up in Rectal Cancer Surgery
Autorzy:: Omarov, Nail
Uymaz, Derya Salim
Kulle, Cemil Burak
Ozkan, Zeynep Gozde
Azamat, Sena
Keskin, Metin
Bulut, Mehmet Turker
Tematy:: computed tomography
magnetic resonance imaging
positron emission tomography-computed tomography
rectal cancer; Pokaż więcej
Wydawca:: Index Copernicus International
Powiązania:: https://bibliotekanauki.pl/articles/58555723.pdf Link otwiera się w nowym oknie
Opis:: Introduction: F-18 fluorodeoxyglucose (F18-FDG) positron emission tomography-computed tomography (PET/CT) is a valuable functional imaging modality for the clinical diagnosis which provides physiological information based on the altered tissue metabolism. Aim: This study aims to investigate the effectiveness of F-18 fluorodeoxyglucose (F18-FDG) positron emission tomography-computed tomography (PET/CT) in preoperative staging and postoperative local recurrence and distant metastases in patients with rectal cancer. Material and methods: The imaging of 726 patients with rectal cancer who were operated on at Istanbul University, Istanbul School of Medicine and had F18-FDG PET/CT, CT, and magnetic resonance imaging (MRI) scans between September 2005 and October 2016 were retrospectively analyzed. Of these patients, 170 who had pre- and postoperative PET/CT scans, had their CT scans included in the study. The sensitivity and specificity of PET/CT in preoperative staging and detection of postoperative local recurrence and distant metastases were analyzed. Results: Of the patients, 101 were males and 69 were females with a median age of 62.27 (range, 31 to 89) years. The sensitivity and specificity of preoperative PET/CT in detecting liver metastases were 100% (confidence interval [CI]: 66.37–100%) and 94.2% (CI: 89.72–100%), respectively (Cohen’s kappa [κ]: 1.00; P < 0.001). The sensitivity and specificity of postoperative PET/ CT in diagnosing liver metastases were 100% (CI: 88.06–100%) and 98% (CI: 9–100%), respectively (Cohen’s κ: 1.00; P < 0.001). The sensitivity and specificity of preoperative PET/CT in detecting lung metastases were 100% (CI: 66.37–100%) and 91.8% (CI: 89.72–100%), respectively (Cohen’s κ: 1.00; P < 0.001). The sensitivity and specificity of postoperative PET/CT in detecting lung metastases were 100% (CI: 91.4–100%) and 96% (CI: 95.8–100%), respectively (Cohen’s κ: 1.00; P < 0.001). The sensitivity and specificity of PET/CT in preoperative staging of pathological pelvic lymph nodes were 100% (CI: 63.06–100%) and 94.29% (CI: 80.84–99.3%), respectively (Cohen’s κ: 0.860; P < 0.001). The sensitivity and specificity of postoperative PET/CT in detecting local recurrences were 100% (CI: 78.2–100%) and 76.74% (CI: 61.37–88.24%), respectively (Cohen’s κ: 0.219; P < 0.08). Results: Given the fact that PET/CT can detect all primary rectal cancer in preoperative staging, it can be effectively used in selected cases, particularly in those suspected of local and advanced disease and with metastases (T3N0, T3N1, and/or T4N1). Due to a relatively low specificity in detecting local recurrences postoperatively, PET/CT can be combined with further modalities.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Tomografia spektralna
Spectral tomography
Autorzy:: Pawałowski, Bartosz
Paluszyńska, Marta
Charmacińska, Magdalena
Bąk, Olga
Graczyk, Kinga
Świątek, Katarzyna
Wosicki, Maksymilian
Piotrowski, Tomasz
Tematy:: tomografia spektralna
tomografia dwuenergetyczna
tomografia komputerowa
tomografia zliczająca fotony
spectral tomography
dual energy tomography
computed tomography
photon counting tomography; Pokaż więcej
Wydawca:: Indygo Zahir Media
Powiązania:: https://bibliotekanauki.pl/articles/58906530.pdf Link otwiera się w nowym oknie
Opis:: W pracy przedstawiono podstawy fizyczne oraz metody realizacji obrazowania spektralnego w tomografii komputerowej. Opisano różnice między metodami zaimplementowanymi komercyjnie w różnych typach tomografów komputerowych. W oparciu o przegląd literaturowy wymieniono możliwe zastosowania tych metod oraz potencjalne zyski wynikające z ich stosowania w porównaniu z klasycznymi metodami obrazowania tomograficznego.
The study presents the physical basics and methods of performing spectral imaging in computed tomography (CT). The differences between the commercially implemented methods in various CT machines are described. Based on the literature review, possible applications of these methods and potential benefits resulting from their use in comparison with classical methods of CT imaging were listed.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Analysis for Improvement of Doppler Tomography Imaging of Objects Scattering Continuous Ultrasonic Waves
Autorzy:: Świetlik, Tomasz
Opieliński, Krzysztof J.
Tematy:: continuous wave ultrasonic tomography
Doppler tomography
image reconstruction; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czasopisma i Monografie PAN
Powiązania:: https://bibliotekanauki.pl/articles/176449.pdf Link otwiera się w nowym oknie
Opis:: The paper describes an innovative ultrasound imaging method called Doppler Tomography (DT), otherwise known as Continuous Wave Ultrasonic Tomography (CWUT). Thanks to this method, it is possible to image the tissue cross-section in vivo using a simple two-transducer ultrasonic probe and using the Doppler effect. It should be noted that DT significantly differs from the conventional ultrasound Doppler method of measuring blood flow velocity. The main difference is that when measuring blood flow, we receive information with an image of the velocity distribution in a given blood vessel (Nowicki, 1995), while DT allows us to obtain a cross-sectional image of stationary tissue structure. In the conventional method, the probe remains stationary, while in the DT method, the probe moves and the examined tissue remains stationary. This paper presents a method of image reconstruction using the DT method. First, the basic principle of correlation of generated Doppler frequencies with the location of inclusions from which they originate is explained. Then the exact process and algorithm in this method are presented. Finally, the impact of several key parameters on imaging quality is examined. As a result, the conclusions of the research allow to improve the image reconstruction process using the DT method.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Radiation dose associated with multi-detector 64-slice computed tomography brain examinations in Khartoum State, Sudan
Autorzy:: Babikir, Esameldeen
Elmahdi, Ali
Abuzaid, Mohamed M.
Sulieman, Abdelmoneim
Opis:: Background: Radiation exposure due to computed tomography (CT) has become an important issue, as the number of CT examinations has been increasing worldwide. Radiation doses associated with CT are higher in comparison to other imaging procedures. CT-related radiation doses should be monitored and controlled in order to ensure reduction of radiation exposure and optimization of image quality. The aim of this study was to evaluate radiation doses in adult patient who underwent routine CT brain examinations, and to assess how CT scanning protocols affect patient doses in practice. Material/Methods: A total of 118 patients underwent brain CT at two radiology departments equipped with 64-slice CT scanners, Khartoum, Sudan. Patient doses regarding weighted CT dose index (CTDIw) and dose length product (DLP) values were recorded. Quality control tests were performed for both scanners. Results: The mean CTDIw values ranged from 62.9 to 65.8 mGy, DLP values ranged from 1003.7 to 1192.5 mGy, and the effective dose varied from 2.4 to 3.7 mSv. Conclusions: Patient doses in this study was higher compared to previous research, suggesting that patients exposed to unnecessary radiation. Therefore, optimization of radiation doses with the use of specified imaging protocols, well-documented indications for CT, training of technicians, and quality control programs will reduce the necessary radiation doses. Establishment of the diagnostic reference level is recommended for further dose reduction.
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

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Skocz do pozycji: 7.

Tytuł:: Utility of brain parenchyma density measurement and computed tomography perfusion imaging in predicting brain death
Autorzy:: Uluer, Hatice
Pekcevik, Yeliz
Sahin, Hilal
Akdogan, Asli I.
Opis:: Purpose: To assess the utility of brain parenchyma density measurement on unenhanced computed tomography (CT) in predicting brain death (BD), in order to evaluate the added value of CT perfusion (CTP). Material and methods: A total of 77 patients who were clinically diagnosed as BD and had both CT angiography (CTA) and CTP imaging in the same session were retrospectively reviewed. On unenhanced phase of CTA, density measurement was performed from 23 regions of interests (ROIs) which were located in the following areas: level of basal ganglia (caudate nucleus, putamen, corpus callosum, posterior limb of internal capsule), level of brainstem, greywhite matters on levels of centrum semiovale (CS), high convexity (HC), and cerebellum. CTP images were evaluated qualitatively and independently. Grey matter (GM), white matter (WM), density, and GM/WM density ratio of BD patients were compared with control subjects. Results: Comparing with the normal control group, the GM and WM density at each level and GM/WM density ratio of CS, HC, and cerebellum level were significantly lower in brain-dead patients (p = 0.019 for HC-WM, p < 0.001 for other areas). Using ROC analysis, the highest value of area under curve (AUC) for the GM/WM density ratio was found at the HC level (AUC = 0.907). The sensitivity of the GM/WM density ratio at the HC level was found to be 90% when the cut-off value of 1.25 was identified. Evaluating the GM/WM density ratio together with the CTP results increased the sensitivity further to 98%. Conclusions: The GM/WM density ratio at the HC level on unenhanced CT may be a useful finding to predict BD. Also, the addition of CTP increases the sensitivity of this method.
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

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Skocz do pozycji: 8.

Tytuł:: Detection of the artery of Adamkiewicz using multidetector row computed tomography in patients with spinal arteriovenous shunt disease
Autorzy:: Konishi, Takahiro
Hoshiai, Sodai
Nakai, Yasunobu
Shiigai, Masanari
Masumoto, Tomohiko
Opis:: Purpose: To plan a treatment strategy for a spinal arteriovenous shunt (SAVS), identifying the artery of Adamkiewicz (AKA) and its origin is indispensable. However, detecting the AKA is very difficult in patients with an SAVS when using computed tomography angiography (CTA) by the usual method to find the hairpin curved artery because dilated drainage veins nearly always coexist with the hairpin curved AKA. We designed a method to identify the AKA by focusing on the diameter and pathway of the anterior radiculomedullary arteries (RMAs). Material and methods: Seven consecutive patients with an SAVS were surveyed. They underwent contrast-enhanced CTA and conventional angiography from January 2009 to December 2012. Two readers evaluated the CTA images and assumed that the AKA was the artery that ran through the anterior portion of the neural foramen and continued to pass on the ventral side of the spinal cord. Results: Among the seven patients, nine AKAs were detected with conventional angiography. When using our method, seven AKAs and six AKAs were identified on CTA by Reader 1 and Reader 2, respectively. The average sensitivity was 72.3%, and the specificity, accuracy, positive predictive value, and negative predictive value were sufficiently high (i.e. > 85%) for both readers. The kappa value for detecting the AKA was 0.98. Conclusions: Detecting the origin of the AKA with CTA is challenging in patients with an SAVS. However, focusing on the diameter and pathway of the RMAs may allow successful identification.
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

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Skocz do pozycji: 9.

Tytuł:: Tomografia impedancyjna w diagnostyce i leczeniu noworodka – doświadczenia wstępne
Impedance tomography in the diagnostics and treatment of a newborn – preliminary experience
Autorzy:: Truszkiewicz, Adrian
Wojtas, Łukasz
Błaż, Witold
Bartusik-Aebisher, Dorota
Nitychoruk, Katarzyna
Tomaszkiewicz, Anna
Aebisher, David
Tematy:: tomografia impedancyjna
tomografia komputerowa
tomograf impedancyjny
impedance tomography
computed tomography; Pokaż więcej
Wydawca:: Indygo Zahir Media
Powiązania:: https://bibliotekanauki.pl/articles/58906544.pdf Link otwiera się w nowym oknie
Opis:: Niniejsze opracowanie stanowi wstępny raport z doświadczeń własnych z wykorzystania tomografu impedancyjnego (EIT) w Klinice Noworodków. Urządzenie to pozwala na diagnostykę małych pacjentów bez wykorzystywania kancerogennego promieniowania rentgenowskiego w kierunku upowietrznienia płuc. Dodatkowo pozwala na analizę pracy układu oddychania w czasie niemalże rzeczywistym. Jest to szczególnie ważne w przypadku wcześniaków, gdzie aparat płucny jest jeszcze niewykształcony, a analiza jego działania oparta była do tej pory o analizę przepływów gazów i utlenienia krwi. Wprawdzie EIT w chwili obecnej nie może wyeliminować w żadnym przypadku wykonywania innych badań, w tym diagnostyki obrazowej, to wydaje się mieć duży potencjał wspomagający diagnostykę najmłodszych pacjentów. Szereg ograniczeń, jakie posiada EIT, ze swoją niską rozdzielczością przestrzenną na czele, plasują obecnie tę technikę na pozycji wspomagającej diagnostykę płuc u wcześniaków i niemowląt. Analiza dostępnej literatury światowej wykazuje, iż badania z wykorzystaniem EIT możliwe są również u pacjentów dorosłych – tutaj technika ta pozwala również na badanie układu oddychania. Należy stwierdzić, iż EIT jest to technika rozwojowa mająca tę przewagę nad innymi metodami badań, iż ma zdolność uwidaczniania badanych struktur w czasie rzeczywistym.
The study is a preliminary report on the experience with the use of impedance tomography (EIT) in the Newborn Clinic. This device allows to monitor lung aeration of little patients without the use of carcinogenic X-rays. In addition, it allows to analyze the work of the respiratory system in virtually real time. This is especially important in the case of premature babies, where the lungs are still underdeveloped and the analysis of their operation has so far been based on the analysis of gas flows and blood oxygenation. Although, at present time, the EIT cannot in any case eliminate other tests, including imaging diagnostics, it seems to have a great potential to support diagnostics of the youngest patients. A number of limitations of EIT, with its low spatial resolution at the fore, place this technique in the position supporting lung diagnostics of premature babies and infants. The analysis of the available world literature shows that the treatment with the use of EIT is also possible in case of adult patients – here this technique allows to examine the respiratory system. It should be stated that EIT is a development technique which has the advantage over other research methods because it has the ability to visualize the examined structures in real time.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Autorzy:: Hajdusianek, Wojciech
Poręba, Rafał
Gać, Paweł
Żórawik, Aleksandra
Opis:: Introduction: Vascular elasticity may be a predictive factor of various diseases. Although stiffening is thought to be a natural consequence of ageing, it can be accelerated by a number of pathological conditions such as hypertension, diabetes, or renal diseases. Aim of the study was to discuss the methodology used to assess aortic stiffness, with particular emphasis on radiological examination. Material and methods: The PubMed and Google Scholar databases were screened from inception to the year 2000 by 2 independent analysts initially working separately and then comparing their results. Results: Assessment of stiffness can be divided into methods not requiring computed tomography scan, such as tonometry of carotid femoral pulse wave velocity, bioelectrical impedance analysis, and cardio ankle vascular index, and methods requiring it, such as multidetector row computed tomography - ECG gated, in which indexes such as aortic distensibility, aortic stiffness, and aortic compliance can be obtained with simultaneous calcification evaluation based on the Agatston score. Discussion: Aortic stiffness was corelated with left ventricular afterload, prehypertension, coronary artery plaques, predic tion of coronary artery diseases, bone demineralization, chronic obstructive pulmonary diseases, and diabetes mellitus. Conclusions: Being a factor of various severe diseases, aortic stiffness may play an important role in the early detection of patients requiring additional medical care.
Dostawca treści:: Repozytorium Uniwersytetu Jagiellońskiego

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