Showing papers by "Franz Fazekas published in 1998"
TL;DR: The development of the NINDS-AIREN criteria for vascular dementia have introduced a new application for these rating scales in investigating and delineating the amount of white matter changes on CT/MRI sufficient to fulfill the criteria.
Abstract: Since the recognition of white matter changes on CT (leukoaraiosis), rating scales for the location and severity of white matter changes have been developed, mainly for research purposes, to investigate factors such as the relation with cognition, risk factors, and pathology. The main purpose of rating scales is to provide scores that can be used in statistical analyses. The development of the NINDS-AIREN criteria for vascular dementia have introduced a new application for these rating scales in investigating and delineating the amount of white matter changes on CT/MRI sufficient to fulfill the criteria. Furthermore, in Alzheimer's disease, recognition of white matter changes may serve to delineate homogeneous groups and help to identify patients with different symptomatology. We reviewed the existing rating scales for CT and MRI and judged their properties and reliability. The ideal rating scale does not yet exist, but different rating scales may serve different purposes, for which some recommendations are made.
254 citations
TL;DR: Correlative histopathologic findings show hyperintense periventricular capping of the frontal horns to reflect predominantly a specific anatomic situation characterized by loosely arranged fine-fiber tracts with low myelin and high extracellular fluid content.
Abstract: Magnetic resonance imaging (MRI) has dramatically enhanced our capability of detecting age-related changes of the brain even before they become clinically apparent. Among those are preferentially alte
180 citations
TL;DR: Inadequate grading of MRI hyperintensities may explain some of the inconsistencies in the reported associations of white matter damage with cerebrovascular risk factors or cognitive functions, and development of a commonly accepted rating scheme would be desirable.
Abstract: Magnetic resonance imaging (MRI) has dramatically increased our ability to detect morphological abnormalities in relation to aging of the brain. Among those changes are alterations of the white matter which display high signal intensity on both proton density and T2-weighted images. They may be seen in the deep and subcortical white matter or in a periventricular location. In clinically asymptomatic individuals the reported prevalence ranges from 20% to 60% for deep and subcortical white matter hyperintensities and from 15% to 94% for periventricular changes. Besides different characteristics of the populations examined these wide ranges are a consequence of quite diverse rating schemes and measurement approaches. Inadequate grading of MRI hyperintensities may also explain some of the inconsistencies in the reported associations of white matter damage with cerebrovascular risk factors or cognitive functions. Therefore development of a commonly accepted rating scheme would be desirable. Histopathologic observations could lay the basis. Hyperintense periventricular capping of the frontal horns and a smooth halo of periventricular hyperintensity have been linked to disruption of the ependymal lining, subependymal gliosis and concomitant loss of myelin. Punctate lesions in the deep and subcortical white matter corresponded to minor perivascular reduction in myelin content possibly because of a lower permeability of thickened arteriolar walls. Larger patchy and confluent hyperintensities, however, appear to indicate more extensive ischemic damage consistent with advanced microangiopathy. In parallel, newer MRI techniques may also contribute to the delineation and separation of these various types of tissue alteration.
89 citations
TL;DR: Mild HHD is safe but failed to demonstrate a significant beneficial effect over the pure rehydration regimen in patients with acute ischemic stroke.
Abstract: Background and Purpose—Experimental studies suggest a beneficial effect of hemodilution on acute ischemic stroke. This was not proven by previous multicenter trials in the clinical setting. Various reasons have been suggested for the failure of these studies, which we attempted to consider in the Multicenter Austrian Hemodilution Stroke Trial (MAHST). Methods—MAHST is a randomized, double-blind, placebo-controlled study of hypervolemic hemodilution (HHD) within 6 hours of a clinically first ischemic stroke localized in the middle cerebral artery territory. The treatment consisted of 10% hydroxyethyl starch 200/0.5 (HES) and was tested against pure rehydration with Ringer’s lactate over a period of 5 days. Our primary outcome measure was clinical improvement within 7 days as measured by the Graded Neurologic Scale (GNS). We performed an adaptive interim analysis to reevaluate the study goal after entering half of the projected number of patients (n=200). At least 600 patients per group would have been requ...
74 citations
TL;DR: A family with affected members in four generations, showing these clinical signs of Roussy-Lévy syndrome and a partial duplication at chromosome 17p11.2, provides evidence against the Rous SYL syndrome as a distinct entity but suggests a close relation with the Charcot-Marie-Tooth syndrome.
38 citations
01 May 1998
TL;DR: The high sensitivity to plaques and the opportunity to simultaneously rule out other gross morphological damage justifies the use of MRI as the primary diagnostic modality in the evaluation of multiple sclerosis.
Abstract: Initial enthusiasm about the role of magnetic resonance imaging (MRI) in the diagnosis of multiple sclerosis decreased substantially with the notion that (a) lesions of various pathological origins may resemble demyelinating plaques and (b) a dissemination of lesions throughout the brain is not unique for multiple sclerosis but may even be a "normal" finding. Current experience still does not allow the identification of the aetiology of a single hyperintensity but has identified multiple features of multiple sclerosis related signal abnormalities which, in combination, provide rather high diagnostic accuracy. Useful characteristics include the distribution of lesions such as a strictly periventricular, infratentorial or juxtacortical location, and involvement of the corpus callosum. The presence of contrast enhancement in some but not all lesions-that is, evidence of both old and new lesions-provides additional diagnostic support. Improved instrumentation for imaging of the spine further extends the diagnostic options. Intramedullary signal abnormalities are detected with increased sensitivity and may disclose the presence of multiple lesions even in patients with an equivocal or a negative MRI of the brain. The high sensitivity to plaques and the opportunity to simultaneously rule out other gross morphological damage justifies the use of MRI as the primary diagnostic modality in the evaluation of multiple sclerosis.
28 citations
Journal Article•
TL;DR: The role of magnetic resonance imaging (MRI) in the diagnosis of multiple sclerosis decreased substantially with the notion that lesions of various pathological origins may resemble demyelinating plaques and a dissemination of lesions throughout the brain is not unique for multiple sclerosis but may even be a "normal" finding as mentioned in this paper.
Abstract: Initial enthusiasm about the role of magnetic resonance imaging (MRI) in the diagnosis of multiple sclerosis decreased substantially with the notion that (a) lesions of various pathological origins may resemble demyelinating plaques and (b) a dissemination of lesions throughout the brain is not unique for multiple sclerosis but may even be a "normal" finding. Current experience still does not allow the identification of the aetiology of a single hyperintensity but has identified multiple features of multiple sclerosis related signal abnormalities which, in combination, provide rather high diagnostic accuracy. Useful characteristics include the distribution of lesions such as a strictly periventricular, infratentorial or juxtacortical location, and involvement of the corpus callosum. The presence of contrast enhancement in some but not all lesions-that is, evidence of both old and new lesions-provides additional diagnostic support. Improved instrumentation for imaging of the spine further extends the diagnostic options. Intramedullary signal abnormalities are detected with increased sensitivity and may disclose the presence of multiple lesions even in patients with an equivocal or a negative MRI of the brain. The high sensitivity to plaques and the opportunity to simultaneously rule out other gross morphological damage justifies the use of MRI as the primary diagnostic modality in the evaluation of multiple sclerosis.
18 citations
Journal Article•
TL;DR: This is a case of herpes simplex encephalitis examined with 99mTc-ethyl cysteinate dimer (ECD) and 99m Tc-hexamethyl propyleneamine oxime (HMPAO) SPECT, which leads to failure to detect the characteristic finding of temporal lobe hyperemia in acute HSE.
Abstract: This is a case of herpes simplex encephalitis (HSE) examined with 99mTc-ethyl cysteinate dimer (ECD) and 99mTc-hexamethyl propyleneamine oxime (HMPAO) SPECT. Static images obtained with 99mTc-ECD showed a reduced tracer uptake of the temporal lobe but focal hyperactivity using 99mTc-HMPAO. Dynamic images indicated regional increase of cerebral blood perfusion with both tracers. Technetium-99m-ECD had rapid washout from the inflamed tissue, while 99mTc-HMPAO had avid uptake. Hypofixation of 99mTc-ECD leads to failure to detect the characteristic finding of temporal lobe hyperemia in acute HSE.
14 citations
Journal Article•
TL;DR: This work has found that the presence of certain otherwise normal alA-eles may, when present in critical combination, effectively function as disease-modifying (or perhaps disease-causing) genes in patients with probable AD.
Abstract: form of brain failure with common clinical and pathological features. These include progressive memory loss, behavioral changes, cognitive impairment, neocortical neurofibrillary tan gles (NFTs), extracellular neuritic plaques and neuronal death. The pathological cascade(s) responsible for hyperphosphorylation of the microtubule-associated protein tau result in the formation of NFTs and the abnormal processing of the amyloid precursor protein, which eventually leads to the extracellular deposition of beta-amyloid and the formation of neuritic plaques have yet to be clearly delineated (2,3 ). Over the past 10 yr, genetic mutations have been identified on chromosomes 21, 14 and 31 that are capable of producing the clinical and pathological features of AD (4-6). In addition, the presence on chromosome 19 of the e4 alA-ele for the apolipoprotein E gene is known to increase the risk for AD (7). This latter finding suggests that the presence of certain otherwise normal alA-eles may, when present in critical combination, effectively function as disease-modifying (or perhaps disease-causing) genes. Clearly, AD is etiologically and pathologically a complex neurodegenerative disorder, and no biochemical basis for this disorder has been established. An analogous situation exists with regard to the potential contribution of comorbid conditions such as cerebrovascular ischemia to the clinical and pathological expression of AD. Although there is no evidence that cerebrovascular disease can produce NFTs or neuritic plaques, multiple infarctions or a single infarction in a critical area can cause dementia. What has remained difficult to determine is whether small-vessel isch emia, such as that often felt to be responsible for the subcortical high T2 signal intensity on MRI, contributes in a clinically meaningful way to the severity of the symptoms or rate of dementia progression in patients with probable AD. In the U.S., approximately as many as 10% of individuals over age 65 suffer from some degree of dementia and the prevalence increases to approximately 40% by age 85 (8 ). The
8 citations
TL;DR: Der zeitliche Verlauf des scheinbaren Diffusionskoeffizienten wurde aus den infarzierten Arealen bestimmt and statistisch beurteilt.
Abstract: Zur diffusionsgewichteten Untersuchung von zerebralen Ischämien wurde eine neuartige Spin-Echo Sequenz mit Multishot Echo Planar Imaging Akquisitionsteil auf einem 1.5-TesIa Klinikgerät mit konventionellem Gradientensystem verwendet. Die vorgestellte Sequenz wurde an Phantomen mit unterschiedlichen Selbstdiffusionskoeffizienten evaluiert. An einer konsekutiven Serie von 34 Schlaganfall-Patienten wurde diese Methode angewandt und ihre diagnostische Wertigkeit mit etablierten Scantechniken (T l W, T2W, FLAIR) bei zerebralen Ischämien verglichen. Der zeitliche Verlauf des scheinbaren Diffusionskoeffizienten wurde aus den infarzierten Arealen bestimmt und statistisch beurteilt.
1 citations
TL;DR: In this article, the Austrian Immunoglobulin in Multiple Sclerosis (AIMS) Studie uberprufte diese Annahme nun erstmals in Form einer randomisierten, doppelblinden, placebokontrollierten Untersuchung an 148 Patienten with schubformiger MS (75 IVIg, 73 Placebo).
Abstract: Auf Grund experimenteller Untersuchungen sowie offener Studien wird seit langem die Moglichkeit einer therapeutischen Wirksamkeit von intravenosem Immunglobulin (IVIg) in der Behandlung der Multiplen Sklerose (MS) diskutiert. Die Austrian Immunoglobulin in Multiple Sclerosis (AIMS) Studie uberprufte diese Annahme nun erstmals in Form einer randomisierten, doppelblinden, placebokontrollierten Untersuchung an 148 Patienten mit schubformiger MS (75 IVIg, 73 Placebo). Monatliche Verabreichung von IVIg in einer Dosierung von 0,15–0,2 g/kg uber einen Zeitraum von 2 Jahren fuhrte zu einem signifikant besseren Verlauf der Behinderung, der sich bei insgesamt 24% der Patienten niederschlug, und Krankheitsschube traten fast nur halb so haufig auf wie unter Placebo. Ein Wirkungseintritt der Behandlung war bereits nach 6 Monaten zu beobachten und vom Schweregrad der Behinderung bei Studienbeginn (geringe neurologische Zeichen ohne Behinderung bis zu gehfahg mit Hilfe) weitgehend unbeeinflust. Die Grosenordnung der beobachteten Therapieeffekte war vergleichbar mit jener, die fur Beta-Interferon und Copolymer 1 beschrieben worden ist. Weitere Studien sind bereits angelaufen, um den zukunftigen therapeutischen Stellenwert von IVIg insbesondere auch bei anderen Verlaufsformen der MS abzusichern.
01 Jan 1998
TL;DR: In this article, the authors present a MR-Aufnahmetechnik for the Singleshot-EPI (SSEPI) Akquisitionstechnik.
Abstract: Für eine Vielzahl klinischer Fragestellungen ist es von besonderer Bedeutung, bestimmte Körperregionen möglichst rasch abbilden zu können. Die Singleshot-EPI (SS-EPI) Akquisitionstechnik ermöglicht es, MR-Bilder innerhalb Bruchteilen einer Sekunden zu erfassen und stellt derzeit die schnellste auf der Fouriermethode basierende MR-Aufnahmetechnik dar. Diese Technik stellt jedoch auch große Anforderungen an die ScannerHardware (Gradientenstärke, -Schaltzeiten, -Verstärkerleistung, -Induktivitäten, Abtastbandbreite) und ist darüberhinaus besonders anfällig auf Offresonanzeffekte (Suszeptibilitätsänderungen, ehem. Verschiebung, Feldinhomogenitäten). Grundlegendes Prinzip der SS-EPITechnik [1] ist, die transversale Magnetisierung (FID, SE) durch einen Zug von Gradientenechos en bloc auszulesen und die Phasenkodierung durch, zwischen den Echos liegende, kurze Gradientenimpulse zu erzeugen (BEPI, Abb.lb N=l). Durch den T2bzw. T2*-AbfaIl der transversalen Magnetisierung und durch den stetig ansteigenden Phasenfehler aufgrund der Offresonanzeffekte kommt es bei entsprechend langer Dauer des EPI-Ausleseteils zu einer starken Modulation des k-Raumes, die starke Bildartefakte hervorruft. Zur Reduktion dieser Artefakte ist es deshalb notwendig, den EPI-Ausleseteil so kurz als möglich (-T2*) zu halten. Es werden dafür hohe Gradientenstärken (1025mT/m) mit großen Anstiegsgeschwindigkeiten (0.01O.lms.mTW) und hohe Abtastbandbreiten (bis -400 kHz) benötigt. Da man für realistische Bildmatrixgrößen (>=128) bald die technischen Grenzen konventioneller MR-Scanner für SS-EPI erreicht bzw. weil für manche Fragestellungen eine etwas längere Meßdauer unbedeutend ist, kann man die Messung in N Durchläufe, sogenannte Interleaves oder Shots mit je M Echos pro Shot aufteilen (Abb.l). Betrachtet man Abb.2, so erkennt man, daß der Zusammenhang zwischen der erforderlichen Scanzeit (TE,TR=kürzest möglich) und der Anzahl der Echos pro Interleaves nicht linear zusammenhängt. Eine Steigerung des/EPIFaktors (Anzahl der Gradientenechos je Interleave) bringt unter Umständen kaum kürzere Aufnahmezeiten, jedoch eine wesentlich größere Anfälligkeit für Bildartefakte. Durch die segmentierte k-Raum-Trajektorie werden bestimmte ky-Zei!en zeitgleich (relativ zum Anregungspuls) gemessen und es kommt zu einer treppenförmigen Modulation des k-Raumes in Phasenkodierrichtung, die Geisterbilder und Bild Verschiebungen hervorrufen kann. Eine quantitative Beurteilung dieser Artefakte ist besonders für Untersuchungen, deren Signaländerung in der Größe weniger Prozent liegt, von Bedeutung (Spin Labeling, BOLD-Effekt).