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Tytuł:
ASL (Arterial Spin Labeling) – historical and current perfusion MR methods
Autorzy:
Guz, Wiesław
Bober, Zuzanna
Ożóg, Łukasz
Truszkiewicz, Adrian
Przypek, Aneta
Aebisher, David
Bartusik-Aebisher, Dorota
Urbanik, Andrzej
Tematy:
perfusion
MR
ASL
Pokaż więcej
Wydawca:
Uniwersytet Rzeszowski. Wydawnictwo Uniwersytetu Rzeszowskiego
Powiązania:
https://bibliotekanauki.pl/articles/454978.pdf  Link otwiera się w nowym oknie
Opis:
Despite continuous scientific and technological advances in MR imaging, MR perfusion methods have not yet been widely deployed for routine clinical diagnostics. This is especially true for ASL (arterial spin labelling) methods used to evaluate cerebral perfusion. This method does not require a contrast agent, as new discoveries about gadolinium accumulation in the cerebellum and brain nucleus appear to be a valuable asset and provide the opportunity to be more widely deployed in clinical practice. The aim of this paper is to present the historical determinants of the development of MR perfusion techniques, the disadvantages and advantages and possible clinical applications and prospects of ASL development. Both historical articles published on MR in the 1990s and current research between 2006-2016 have been reviewed. The authors present in the work the MR perfusion method focusing on issues related to arterial spin labeling (ASL). Historically CASL (continuous ASL) and PCSL (pulsed ASL) techniques have been described and the pseudocontinuous ASL (pseudocontinuous ASL) 3D technique presents its technical and methodological considerations, advantages and disadvantages over previous methods. The methods of test protocol optimization and accompanying artifacts, as well as possible clinical applications and development perspectives, have been described.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Preliminary experience with dynamic CT myocardial perfusion imaging : a single-centre perspective
Autorzy:
Guziński, Maciej
Puła, Michał
Korbecki, Adrian
Sobański, Michał
Zdanowicz-Ratajczyk, Agata
Opis:
Purpose: This study aimed to optimise the dynamic coronary computed tomography perfusion (CTP) protocol, focusing on patient preparation, scanning parameters, and image acquisition, reconstruction, and interpretation. Future phases will evaluate the diagnostic accuracy of dynamic CTP in detecting haemodynamically significant coronary artery disease (CAD), using invasive coronary angiography (ICA) and fractional flow reserve (FFR) as reference standards. Material and methods: Thirty-six symptomatic patients with confirmed or suspected CAD underwent dynamic CTP using a whole-heart coverage CT scanner (Revolution Apex CT, GE Healthcare). Two patients were excluded due to non-diagnostic CTP results. Of the remaining 34 patients, 24 underwent both cardiac CT angiography (CCTA) and CTP, while 19 underwent CCTA, CTP, and ICA. Preliminary data were analysed by comparing CTP findings with CCTA and ICA/FFR when available. Results: Among 578 myocardial segments, 424 (73.3%) showed normal perfusion and 154 (26.6%) exhibited hypoperfusion. Of the 17 cases with perfusion deficits, ICA confirmed significant stenosis in 10, resulting in 100% sensitivity and 22% specificity for detecting haemodynamically significant stenosis. FFR assessment in 10 patients demonstrated 60% concordance between CTP, ICA, and FFR. Incorporating CTP into the diagnostic pathway led to a 29.4% reclassification in management strategies. Conclusions: The low specificity observed for detecting significant CAD underscores the need for further refinement of the CTP protocol. Future research should aim to optimise myocardial blood flow thresholds to improve diagnostic specificity and clinical applicability.
Dostawca treści:
Repozytorium Uniwersytetu Jagiellońskiego
Artykuł
Tytuł:
Single photon emission computed tomography as a diagnostic method in ischemic heart disease : basic technical aspects
Opis:
Ischemic Heart Disease (IHD) poses an important diagnostic problem. Clinical picture of the disease is often atypical. SPECT is one of the main diagnostic tools in ischemic heart disease. Radioisotope study evaluates distribution of a radiopharmaceutical agent in the heart through a series of scintigraphic images taken by an external gamma camera. This article discusses the technical aspects of cardiac SPECT imaging, starting with a detection system, through image reconstruction, and ending with image filtering.
Dostawca treści:
Repozytorium Uniwersytetu Jagiellońskiego
Artykuł
Tytuł:
The effect of software post-processing applications on identification of the penumbra and core within the ischaemic region in perfusion computed tomography
Autorzy:
Chrzan, Robert
Gleń, Agnieszka
Urbanik, Andrzej
Opis:
Purpose: Assessment of software applications designed for post-processing of CT imaging data and perfusion maps in terms of their ability to consistently define the penumbra and core in an ischemic area. Material and methods: This study is based on measurements conducted in a group of 65 patients with neurological symptoms suggestive of ischaemia in the area of the MCA within 12 hours following onset of the first symptoms. Non-contrast and perfusion CT were performed during an emergency duty. The acquired data were processed using various programs to obtain defined ischaemic areas and parameters. Finally, the results obtained were compared to the distribution of penumbra and core within the ischaemic area received from different perfusion mapping programs. Results: The programs designed to convert the acquired data and to map the distribution of perfusion were also assessed for their viability in dividing the ischaemic zone into penumbra and core. There was a statistically strong correlation (0.784-0.846) between results obtained by processing of imaging data with two different packages, and then by post-processing with one package, and a poor correlation (0.315-0.554) between results obtained by processing of data with the same package, and post-processing with two different packages designed for measuring penumbra and core areas. Conclusions: The results obtained by processing of imaging data with different software applications and by post-processing with one program developed for identifying penumbra and core areas show a strong correlation. However, the results obtained by processing imaging data with the same software application and by post-processing with different programs measuring penumbra and core areas reveal poor correlation.
Dostawca treści:
Repozytorium Uniwersytetu Jagiellońskiego
Artykuł
Tytuł:
Intestinal absorption of xylitol and effect of its concentration on glucose and water absorptiom in the small intestine of rat
Autorzy:
Frejnagel, Sławomir
Gomez-Villalva, Elena
Zduńczyk, Zenon
Karamać, Magdalena
Tematy:
polyol
xylitol
intestinal absorption
perfusion
rat
Pokaż więcej
Wydawca:
Instytut Rozrodu Zwierząt i Badań Żywności Polskiej Akademii Nauk w Olsztynie
Powiązania:
https://bibliotekanauki.pl/articles/2051049.pdf  Link otwiera się w nowym oknie
Opis:
In experiment on rats, using perfusion technique of small intestine, xylitol absorption and its influence on water and glucose absorption was determined. Perfusion fluid contained from 2.5 g to 20 g of xylitol and 2 g of glucose per liter. Quantitatively, xylitol absorption increased with the increase of this substance in perfusion liquid. However, relative absorption was the same in all groups and amounted 19-20% of xylitol incorporated to the beginning of the small intestine . Introduction of substance possessing osmotic properties to perfusion fluid caused decrease of water and glucose absorption.Addition of xylitol to liquid resulted in significant lowering of glucose absorption from 80.8 g/h/rat in control group to 60.8 g/h/rat in group with the greatest amount of xylitol. Dose-dependent decrease of water absorption from 12 ml/h/rat in control group to 0.17 ml/h/rat in group containing the highest amount of xylitol in perfusion liquid was recorded.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The value of perfusion CT in evaluating locoregional staging in post-radical prostatectomy patients with elevated serum PSA level
Autorzy:
Stelmach, Andrzej
Łuczyńska, Elżbieta
Jaszczyński, Janusz
Anioł, Joanna
Opis:
Background: The aim of the study was to evaluate the efficiency of perfusion CT (p-CT) in assessing cancer foci in the prostate gland in patients with elevated PSA level who had radical prostatectomy after the p-CT exam. Material/Methods: Prostate p-CT was performed at the Oncology Institute, Cracow, in 2006 in 24 patients aged 49-72 years. The examination was followed by core needle biopsy of the prostate (6-12 cores). PSA levels in the blood ranged from 5.15 to 33.1 ng/ml. The Gleason score estimated after radical prostatectomy ranged from 5 to 8. The parameters BF, BV, PS, and MTT for both prostate lobes at three levels (base, mid-gland, and apex) were measured. Relationships between the presence of pathological foci found in p-CT, serum PSA level, and histopathological findings in the removed prostate gland were analyzed. Results/Conclusions: On the basis of the analyzed material, positive correlation was found between serum PSA level and Gleason score in the post-radical prostatectomy patients. Positive correlation was also found between serum PSA and the presence of pathological lesions detected in p-CT. The higher the level of serum PSA, the higher the probability of detecting a pathological lesion within the prostate gland. No significant correlation between histopathological and p-CT outcome concordance and serum PSA level was noted. However, no correlation between Gleason score and p-CT examination results was found, which suggests that there is no relationship between Gleason score and presence of pathological foci detected in p-CT examination.
Dostawca treści:
Repozytorium Uniwersytetu Jagiellońskiego
Artykuł
Tytuł:
Venous return in acute ischaemic stroke patients measured during computed tomography angiography of head and neck
Autorzy:
Łasocha, Bartłomiej
Wrona, Paweł
Grochowska, Anna
Pułyk, Roman
Latacz, Paweł
Popiela, Tadeusz
Słowik, Agnieszka
Brzegowy, Paweł
Opis:
Introduction: The aim of this study was to analyse the general features and usefulness of the time elapsed between the start of contrast agent infusion and its appearance in the aortic arch in acute ischaemic stroke patients subjected to baseline computed tomographic angiography. This is, to the best of our knowledge, the first study of this parameter in a clinical context. We will refer to it hereafter as ‘needle-to-aorta delay’ (NAD). Material and methods: The following were recorded: the time it took iodinated contrast media to reach the aorta, the site of occlusion, and automatic perfusion assessments of infarct and salvageable tissue volumes. Demographic data such as age and sex, comorbidities, and clinical factors including heart rate, blood pressure, time elapsed from symptom onset, initial stroke severity, and course of disease, were also assessed. Results: We analysed 252 cases of stroke. NAD correlated with tissue at risk volume, and was greater for patients with hypertension and atrial fibrillation. The observed time was significantly shorter with less favourable core-to-penumbra ratios. No link was found between NAD and either the rate of infarct progression or the long-term clinical result. Conclusions: Although no clinical benefit was proven as a result of measuring the time it took contrast media to reach the aorta, our study implies that not only is the brain subject to circulation, but it may also affect its functioning.
Dostawca treści:
Repozytorium Uniwersytetu Jagiellońskiego
Artykuł
Tytuł:
Automatyczna detekcja elementów asymetrii w dynamicznych mapach CBF perfuzji mózgowej
Automatic detection od asymmetry elements in dynamic CBF brain perfusion maps
Autorzy:
Hachaj, T.
Tematy:
dynamiczna perfuzja CT
detekcja asymetrii
konwolucyjny model Meiera-Zierlera
dynamiczna perfuzja
mapy perfuzji
CBF
dynamic CT perfusion
assymetry detection
Meier-Zierler convolution model
dynamic perfusion
perfusion maps
Pokaż więcej
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Powiązania:
https://bibliotekanauki.pl/articles/320276.pdf  Link otwiera się w nowym oknie
Opis:
W artykule zaprezentowano nowy algorytm pozwalający na detekcję asymetrii na dynamicznych mapach perfuzji mózgowej CBF. W pierwszym etapie algorytm dokonuje detekcji osi symetrii zobrazowania przechodzącej pomiędzy półkulami mózgowymi. W drugim etapie algorytm ocenia stopień asymetrii przepływu krwi w zobrazowaniu poprzez detekcję regionów o różnym przepływie w obu półkulach mózgowych. Algorytm został przetestowany na 28 zobrazowaniach perfuzyjnych, wśród których znajdowały się zarówno przypadki z nieprawidłowości w przepływie krwi mózgowej, jak i przypadki bez anomalii przepływu. Omówiony został również sposób pomiaru ilości krwi przepływającej przez mózg przy użyciu niedyfundującego wskaźnika w oparciu o konwolucyjny model Meiera-Zierlera oraz sposób konstrukcji map CBF, CBV, MTT i TTP.
This paper presents a new algorithm that enables detection of asymmetry in dynamic CBF perfusion maps. In the first stage of the algorithm detection of symmetry axis of image (between left and right hemisphere) is performed. In the second stage the level of asymmetry in cerebral blood flow is measured by detection of regions with different perfusion in both brain hemispheres. The algorithm was tested on a set of 28 different images showing or not cerebral blood flow anomalies. The paper also describes the method for estimating cerebral blood flow with a non dijfusing contrast agent based on the Meier-Zierler convolution model as well as CBF, CBV, MTT and TTP perfusion maps.
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-10 z 85

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