MRI in diagnostics of failing cerebral perfusion

Background and Purpose: The employment of Magnetic resonance (MR) in investigations of cerebral tissue in health and disease achieved during the last 3 decades great appreciation. Its spectacular results in MR imaging and spectroscopy are especially useful in the domain of brain ischaemia. Materials and Methods: We have combined practical experience with search in literature to create a review of possible examinations in the field of stroke and chronic cerebrovascular insufficiency. Results and Conclusions: Our survay contains chapters on the causes of cerebral ischaemia, described in methods ofMR angiography and Perfusion weighted imaging and chapters on the consequences of ischaemia: Imaging of the ischaemic cascade by classical spin echo sequences, imaging of diffusion, of contrast enhancement and distinction of the surviving parts in the hypoperfused regions. Magnetic resonance spectroscopy is reported in its proton and phosphorus examinations. Longlasting diminushion of cerebral blood flow with aging is reviewed in the last chapter

Obrazowanie tensora dyfuzji u pacjentów z chorobą Alzheimera i łagodnymi zaburzeniami poznawczymi

A wide range of imaging studies provides growing support for the potential role of diffusion tensor imaging (DTI) in evaluating microstructural white matter integrity in Alzheimer disease (AD) and mild cognitive impairment (MCI). Our review aims to present DTI principles, post-processing and analysis frameworks and to report the results of particular studies. The distribution of AD-related white matter abnormalities is widely discussed in the light of deteriorated connectivity within certain tracts due to secondary white matter degeneration; primary alterations are also assumed to contribute to the pattern. The question whether it is more effective to assess the whole-brain diffusion or to directly concentrate on specific regions remains an interesting issue. Assessing white matter microstructure alterations, as evaluated by group-level differences of tensor-derived parameters, may be a promising neuroimaging tool for differential diagnosis between AD, MCI and other cognitive disorders, as well as being particularly helpful in the interpretation of underlying pathological processes.Rosnąca liczba badań naukowych wskazuje na znaczenie obrazowania tensora dyfuzji (DTI) w ocenie mikrostrukturalnej integralności istoty białej w chorobie Alzheimera (ChA) i łagodnych zaburzeniach poznawczych (ŁZP). W niniejszej pracy przeglądowej omówiono zasady obróbki danych oraz analizy DTI i przedstawiono wyniki poszczególnych badań prezentujących różne modele charakterystycznych dla ChA zmian w istocie białej. Szeroko dyskutowane jest rozmieszczenie uszkodzeń w istocie białej, głównie w odniesieniu do wtórnego zwyrodnienia poszczególnych włókien wskutek zaniku istoty szarej lub pierwotnego zwyrodnienia istoty białej. Interesujący i nierozstrzygnięty pozostaje dylemat, czy bardziej efektywne jest obrazowanie zmian dyfuzji w całym mózgu, czy skupianie się na konkretnych strukturach. Zastosowanie DTI w ocenie mikrostrukturalnych zmian zachodzących w istocie białej mózgu może być obiecującym narzędziem w różnicowaniu pomiędzy ChA, ŁZP i innymi zaburzeniami poznawczymi; jest szczególnie przydatne przy interpretacji leżących u ich podłoża procesów patologicznych

Commission des Communautes Europeennes: Groupe du Porte-Parole. Reunion de la Commission du mercredi 29 octobre 1980 = Commission of European Communities: Spokesman Group. Meeting of the Commission on Wednesday, 29 October 1980. Spokesman Service Note to National Offices Bio No. (80) 432, 30 October 1980

We study strong-field ionization and rescattering beyond the long-wavelength limit of the dipole approximation with elliptically polarized mid-IR laser pulses. Full three-dimensional photoelectron momentum distributions (PMDs) measured with velocity map imaging and tomographic reconstruction revealed an unexpected sharp ridge structure in the polarization plane (2018 Phys. Rev. A 97 013404). This thin line-shaped ridge structure for low-energy photoelectrons is correlated with the ellipticity-dependent asymmetry of the PMD along the beam propagation direction. The peak of the projection of the PMD onto the beam propagation axis is shifted from negative to positive values when the sharp ridge fades away with increasing ellipticity. With classical trajectory Monte Carlo simulations and analytical analysis, we study the underlying physics of this feature. The underlying physics is based on the interplay between the lateral drift of the ionized electron, the laser magnetic field induced drift in the laser propagation direction, and Coulomb focusing. To apply our observations to emerging techniques relying on strong-field ionization processes, including time-resolved holography and molecular imaging, we present a detailed classical trajectory-based analysis of our observations. The analysis leads to the explanation of the fine structure of the ridge and its non-dipole behavior upon rescattering while introducing restrictions on the ellipticity. These restrictions as well as the ionization and recollision phases provide additional observables to gain information on the timing of the ionization and recollision process and non-dipole properties of the ionization process.ISSN:1361-6455ISSN:0368-3508ISSN:0953-4075ISSN:0022-370

2020 taxonomic update for phylum Negarnaviricota (Riboviria: Orthornavirae), including the large orders Bunyavirales and Mononegavirales.

In March 2020, following the annual International Committee on Taxonomy of Viruses (ICTV) ratification vote on newly proposed taxa, the phylum Negarnaviricota was amended and emended. At the genus rank, 20 new genera were added, two were deleted, one was moved, and three were renamed. At the species rank, 160 species were added, four were deleted, ten were moved and renamed, and 30 species were renamed. This article presents the updated taxonomy of Negarnaviricota as now accepted by the ICTV

Diffusion Weighted Imaging and Other Quantitative MRI Methods in the Diagnostics of Selected CNS Diseases

The aim of this study was to assess the scope of exploitation of the diffusion weighted imaging and other quantitative MR methods in the clinical diagnostics. We calculated the normal values of fractional an- isotropy (FA) in our group of healthy volunteers and proved FA depen- dence on age in some regions of brain using regression analysis. The relationship was quadratic in the splenium of callosal body, the left pre- central gyrus and in the pyramidal tract at the level of mesencephalon on the right. Linear decrease of FA with age was found in the rostrum of callosal body, in the white matter of frontal lobes, in the anterior limb of internal capsule on both sides and in the pyramidal tract at the level of mesencephalon on the left. In all measured parts of basal ganglia FA in- creased. Based on our data set, we propose a non-linear colour look-up table (LUT) to enhance the pathologic values. The use of this LUT is presented in patients with several neurological disorders. Quantitative methods were used also for assessment of the group of patients suffering from ALS. The changes we expected in the posterior limb of internal capsule were not significant, therefore we suppose that the presence of T2 hyperintensity in this region is not a reliable marker of the disease. T2 relaxometry detected the..

Diffusion Weighted Imaging and Other Quantitative MRI Methods in the Diagnostics of Selected CNS Diseases

The aim of this study was to assess the scope of exploitation of the diffusion weighted imaging and other quantitative MR methods in the clinical diagnostics. We calculated the normal values of fractional an- isotropy (FA) in our group of healthy volunteers and proved FA depen- dence on age in some regions of brain using regression analysis. The relationship was quadratic in the splenium of callosal body, the left pre- central gyrus and in the pyramidal tract at the level of mesencephalon on the right. Linear decrease of FA with age was found in the rostrum of callosal body, in the white matter of frontal lobes, in the anterior limb of internal capsule on both sides and in the pyramidal tract at the level of mesencephalon on the left. In all measured parts of basal ganglia FA in- creased. Based on our data set, we propose a non-linear colour look-up table (LUT) to enhance the pathologic values. The use of this LUT is presented in patients with several neurological disorders. Quantitative methods were used also for assessment of the group of patients suffering from ALS. The changes we expected in the posterior limb of internal capsule were not significant, therefore we suppose that the presence of T2 hyperintensity in this region is not a reliable marker of the disease. T2 relaxometry detected the...SOUHRN Cílem práce bylo zhodnotit možnosti difuzí váženého zobrazení a dal- ších kvantitativních MR metod v klinické diagnostice. Stanovili jsme nor- mální hodnoty frakční anizotropie (FA) ve vlastním souboru a regresní analýzou jsme v některých oblastech šedé i bílé hmoty mozku prokázali závislost FA na věku. Tento vztah byl kvadratický ve spleniu corporis callosi, levém precentrálním gyru a pyramidové dráze v oblasti mesence- phala vpravo. Lineární pokles FA s věkem jsme nalezli v rostrum corporis callosi, v bílé hmotě čelních laloků, v předním raménku capsula interna oboustranně a v pyramidové dráze v úrovni mesencephala vlevo. Ve všech měřených oblastech bazálních ganglií jsme prokázali naopak vzestup FA. Na základě našich dat jsme navrhli nelineární barevnou škálu k zvýraz- nění patologických hodnot, na vybraných neurologických afekcích jsou demonstrovány možnosti jejího užití. Kvantitativních metod jsme dále použili pro hodnocení souboru dat pacientů s ALS. Předpokládané změny v zadním raménku capsula in- terna se nepotvrdily, přítomnost T2 hyperintenzity v této oblasti tudíž není pro ALS patognomická. T2 relaxometrie caput nuclei caudati ukázala u našich pacientů ve srovnání s kontrolní skupinou pokles relaxační rych- losti, což podporuje hypotézu, že se subkortikální šedá hmota...Department of Neurology 3FM CU and UHKVNeurologická klinika 3. LF UK a FNKV3. lékařská fakultaThird Faculty of Medicin

Diffusion Weighted Imaging and Other Quantitative MRI Methods in the Diagnostics of Selected CNS Diseases

The aim of this study was to assess the scope of exploitation of the diffusion weighted imaging and other quantitative MR methods in the clinical diagnostics. We calculated the normal values of fractional an- isotropy (FA) in our group of healthy volunteers and proved FA depen- dence on age in some regions of brain using regression analysis. The relationship was quadratic in the splenium of callosal body, the left pre- central gyrus and in the pyramidal tract at the level of mesencephalon on the right. Linear decrease of FA with age was found in the rostrum of callosal body, in the white matter of frontal lobes, in the anterior limb of internal capsule on both sides and in the pyramidal tract at the level of mesencephalon on the left. In all measured parts of basal ganglia FA in- creased. Based on our data set, we propose a non-linear colour look-up table (LUT) to enhance the pathologic values. The use of this LUT is presented in patients with several neurological disorders. Quantitative methods were used also for assessment of the group of patients suffering from ALS. The changes we expected in the posterior limb of internal capsule were not significant, therefore we suppose that the presence of T2 hyperintensity in this region is not a reliable marker of the disease. T2 relaxometry detected the..

Importance of Imaging Methods for the Diagnostics of Primary Traumatic Brain Injury

Radiodiagnostická klinikaDeparment of RadiodiagnosticsThird Faculty of Medicine3. lékařská fakult