[Jejunum stenosis as a late sequela of small-intestinal involvement in Wegener's granulomatosis].
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Female↗
Biomedical subjects
F Gückel
Publications and source records attributed to F Gückel.
MRI of encephalitis in children: comparison of CT and MRI in the acute stage with long-term follow-up.
We examined 14 children aged 28 days to 12.7 years with encephalitis by CT or MRI. Of the patients examined by CT 58% had a normal first scan, whereas all MRI investigations demonstrated abnormalities. The clinical features correlated with several MRI investigations. On MRI herpes (HSV) encephalitis started in the medial temporal lobe and encephalomalacia developed within a few weeks. All patients had a follow-up examination 0.5 to 6.5 years after the acute phase. MRI revealed abnormalities in 13 of the 14 children; one boy, with lesions in only the white matter, had a normal follow-up MRI. Even with immediate, optimal therapy the children demonstrated severe parenchymal abnormalities. Signal abnormalities seen in the acute phase of the disease were likely to persist. In children with HSV encephalitis atypical lesions in different areas were seen.
Acute Disease↗
Age dependency of the regional cerebral blood volume (rCBV) measured with dynamic susceptibility contrast MR imaging (DSC).
The changes of the regional cerebral blood volume (rCBV) with age were studied using dynamic susceptibility contrast MRI (DSC). We examined an unselected, random sample of 71 consecutive patients referred for work-up of suspected intracranial tumors (35 normal examinations, 36 tumors) with a standard 1.5 T clinical MR system. Determination of the rCBV was performed with a T2*-weighted simultaneous dual (SD) FLASH sequence (TR/TE1/TE2/alpha = 32/25/16/10 degrees, 55 images) after bolus injection of Gd-DTPA. Absolute quantification of the rCBV was achieved by normalizing the measured tissue concentration-time curves with the integrated arterial input function (AIF), which was simultaneously measured in the brain feeding arteries. The rCBV (mean +/- SD) was 8.4 +/- 2.9 ml/100 g and 4.2 +/- 1.7 ml/100 g in gray and white matter, respectively, with a decline of about 3% and 6% per decade for white and gray matter, respectively. We conclude that DSC using a SD FLASH sequence allows the simultaneous measurement of the AIF and the tissue concentration-time curve and thus an absolute quantification of the rCBV, which is the basis for interperson comparisons and follow-up studies.
Adult↗
Functional MR imaging of semantic information processing and learning-related effects using psychometrically controlled stimulation paradigms.
Functional magnetic resonance imaging (fMRI), in conjunction with carefully designed, psychometrically optimized stimulation procedures, was used to investigate the relation between brain activation and the processing of word associations. A semantic discrimination task of word-pair similarity was performed by normal subjects (n = 17) within a clinical 1.5-Tesla whole-body MRI system. A color similarity task of psychometrically equivalent difficulty, as indicated by behavioral data acquired online during fMRI, served as active control condition. Comparisons between tasks dramatically improved results compared to comparisons between task and resting condition. The language paradigm selectively activated left frontal and left fronto-temporal areas. Cortical activation during the semantic task decreased significantly over three runs of the same word list and was paralleled by decreased reaction times. No such changes were observed in the active control condition indicating selective learning of the language task only. When combined with psychological activation schemes and the acquisition of behavioral data, fMRI represents a powerful tool for the study of brain-behavior interaction.
Adult↗
[Functional magnetic resonance tomography during the activation of working memory].
AIMS: Functional magnetic resonance imaging was used in conjunction with a letter detection task for the study of working memory in 16 normal subjects. Because of movement artifacts, data from only 9 subjects were analysed. METHODS: In the activation task, subjects responded by pressing a button whenever any presented letter was the same as the second last in the sequence. In the control condition, the subjects had to respond to a fixed letter. Hence, the activation condition and the control condition differed only subjectively, i.e., regarding the task demand, whereas the stimuli and the type and frequency of response were identical. RESULTS: The activation condition produced significant activation in the dorsolateral prefrontal cortex (Brodmann's areas 10, 46, and 9). CONCLUSIONS: In contrast to experimental tasks previously used rather extensively to study the prefrontal cortex, the present paradigm is characterized by its simplicity, interpretability, and its ties to known neurophysiology of the frontal cortex.
Adult↗
Assessment of regional cerebral blood volume in acute human stroke by use of single-slice dynamic susceptibility contrast-enhanced magnetic resonance imaging.
BACKGROUND AND PURPOSE: The purpose of this study was to evaluate the clinical usefulness of dynamic susceptibility contrast-enhanced MRI (DSC-MRI) in acute cerebral ischemia. METHODS: During bolus injection of gadolinium-diethylenetriamine pentaacetic acid, a series of rapid T2*-weighted images was recorded from one slice. Concentration-time curves and images of regional cerebral blood volume (rCBV) were calculated from this data set. DSC-MRI, MR angiography, conventional spin-echo MRI (SE-MRI), and CT were performed in 11 patients within 6 hours after stroke onset and before thrombolytic or anticoagulant treatment was begun. A follow-up MRI examination was performed 24 to 48 hours after stroke onset. RESULTS: In 7 of 11 patients (group 1) with territorial infarcts of the middle (n = 6) or posterior cerebral artery (n = 1), DSC-MRI showed reduced rCBV in the affected territory before conventional SE-MRI displayed ischemic lesions. DSC-MRI was helpful to differentiate severely ischemic tissue from peri-infarct parenchyma. Partial reperfusion (n = 3), unchanged reduction of rCBV (n = 2), and progressive reduction of rCBV (n = 2) were observed in the follow-up study. Normal DSC-MRI findings were present in 4 of 11 patients (group 2) with lacunar infarcts. CONCLUSIONS: DSC-MRI accomplished the detection of the ischemic territory in the very early stage (< 6 hours) before SE-MRI delivered unequivocal results. DSC-MRI might be helpful to discriminate completely ischemic tissue from potentially salvageable ischemic parenchyma at risk and may play an important role in stroke therapy and evaluation.
Aged↗
[Neurofunctional MRI imaging of higher cognitive performance of the human brain].
Functional magnetic resonance imaging (fMRI) offers a powerful experimental tool for mapping activated cortical regions in man. Thereby, the paramagnetic deoxyhemoglobin in the red blood cells acts as an endogenous susceptibility contrast agent, which allows the noninvasive detection of stimulus-induced transient changes in regional cerebral blood flow and volume. Fifteen normal subjects were examined on a conventional 1.5-T MR system to visualize cortical activation during the performance of high-level cognitive tasks. A computer-controlled videoprojector was employed to present psychometrically optimized activation paradigms. Reaction times and error rates of the volunteers were acquired online during stimulus presentation. The time course of cortical activation was measured in a series of strongly T2*-weighted gradient-echo images from three or four adjacent slices. For anatomical correlation, picture elements showing a stimulus-related significant signal increase were color-coded and superimposed on T1-weighted spin-echo images. Analysis of the fMRI data revealed a subtle (range 2-5%), but statistically significant (P < 0.05) increase in signal intensity during the periods of induced cortical activation. Judgment of semantic relatedness of word pairs, for example, activated selectively cortical areas in left frontal and left temporal brain regions. The strength of cortex activation in the semantic task decreased significantly in the course of stimulus presentation and was paralleled by a decrease in the corresponding reaction times. With its move into the area of cognitive neuroscience, fMRI calls both for the careful design of activation schemes and for the acquisition of behavioral data. For example, brain regions involved in language processing could only be identified clearly when psychometrically matched activation paradigms were employed. The reaction time data correlated well with selective learning and thus helped to facilitate interpretation of the fMRI data sets.
Arousal↗
[Noninvasive quantification of cerebral blood volume and blood flow with dynamic MR tomography. Studies of probands and patients with cerebrovascular insufficiency].
PURPOSE: A non-invasive MR-method for the quantification of regional cerebral blood flow (rCBF) and blood volume (rCBV) is used to examine healthy volunteers and patients with cerebrovascular disorders. MATERIALS AND METHODS: 20 healthy volunteers and 10 patients with severe cerebrovascular disorders were examined. MR imaging was performed on a 1.5 T imaging system. Before, during and following brief antecubital vein bolus injection of Gd-DTPA, a series of 32 rapid T2*-weighted gradient echo images of two different slices ere simultaneously acquired in order to measure th concentration-time-curves in the brain tissue and the arterial input function in the brain feeding arteries. From these series of images the concentration-time-curves were computed. Principles of indicator dilution analysis were applied to compute rCBF and rCBV. The volunteers underwent one examination each. All patients underwent two examinations, one before and the second after azetazolamide stimulation. RESULTS: In volunteers the measured rCBF and rCBV values are in good agreement with data from positron emission tomography studies. In patients with cerebrovascular disorders in the asymptomatic hemisphere a mean increase of rCBF of 43,45 +/- 18.04% was observed after azetazolamide stimulation. In the affected areas of the symptomatic hemisphere in 8 from 10 patients the acetazolamide test reveals a significantly reduced response to azetazolamide stimulation, indicating an exhausted cerebrovascular reserve capacity. CONCLUSION: Dynamic MR-Imaging can provide quantitative information about rCBF and rCBV. In patients with cerebrovascular disorders, this method can be applied to estimate the cerebrovascular reserve capacity.
Acetazolamide↗
[Titanium aneurysm clips and their advantages in diagnostic imaging].
Aneurysms clips made of a titanium alloy (TiAl6V4) were used in clinical practice for the first time. The design of the clips is identical to the routinely used Yasargil series. In 30 patients, 38 symptomatic and asymptomatic aneurysms were fixed with 45 clips. Metallurgical advantages of the new alloy are better biocompatibility, less magnetic susceptibility, and lower X-ray density. The postoperative imaging results are superior to the conventionally used alloys with respect to artifact reduction in computed tomography, angiography, and magnetic resonance imaging. With a follow-up period of 7 months, a statement on biocompatibility cannot yet be given.
Alloys↗
Quantification of regional cerebral blood flow and volume with dynamic susceptibility contrast-enhanced MR imaging.
PURPOSE: Quantification of regional cerebral blood flow (rCBF) and volume (rCBV) with dynamic magnetic resonance (MR) imaging. MATERIALS AND METHODS: After bolus administration of a paramagnetic contrast medium, rapid T2*-weighted gradient-echo images of two sections were acquired for the simultaneous creation of concentration-time curves in the brain-feeding arteries and in brain tissue. Absolute rCBF and rCBV values were determined for gray and white brain matter in 12 subjects with use of principles of the indicator dilution theory. RESULTS: The mean rCBF value in gray matter was 69.7 mL/min +/- 29.7 per 100 g tissue and in white matter, 33.6 mL/min +/- 11.5 per 100 g tissue; the average rCBV was 8.0 mL +/- 3.1 per 100 g tissue and 4.2 mL +/- 1.0 per 100 g tissue, respectively. An age-related decrease in rCBF and rCBV for gray and white matter was observed. CONCLUSION: Preliminary data demonstrate that the proposed technique allows the quantification of rCBF and rCBV. Although the results are in good agreement with data from positron emission tomography studies, further evaluation is needed to establish the validity of method.
Brain↗
[Nuclear magnetic resonance tomography as a functional diagnostic method. New approaches to non-invasive quantification of cerebral blood volume and blood flow].
This paper presents a brief introduction to the current status of cerebral blood volume and blood flow imaging with magnetic resonance imaging (MRI) techniques. A new method for the quantitative assessment of regional cerebral blood volume (rCBV) and regional cerebral blood flow (rCBF) on the basis of the indicator dilution theory is described and preliminary quantitative results from healthy volunteers are presented. The mean values for the rCBV are 8.27 +/- 1.85 ml/100 g for grey matter and 3.78 +/- 1.34 ml/100 g for white matter. The mean values for the rCBF are 44.8 +/- 11.29 ml/min/100 g for the grey matter and 20.88 +/- 8.42 ml/min/100 g for the white matter. These results are in good agreement with PET results from the literature.
Adolescent↗
[Noninvasive diagnosis of cerebral ischemia with nuclear magnetic resonance tomography and near infrared spectroscopy].
We describe the non-invasive assessment of cerebrovascular reserve capacity by means of near-infrared spectroscopy (NIRS) and magnetic resonance imaging. Both methods are compared with transcranial Doppler sonography. There is a good correlation of the three methods in the changes in cerebral oxygen saturation and in blood velocity following acetazolamide stimulation of cerebral blood flow, except found in one patient with unilateral carotid artery occlusion. In this patient we found a decreased cerebrovascular reserve capacity, revealed by a magnetic resonance technique designed to quantify CBV and CBF. We postulate a raised oxygen extraction as the cause of his changes in oxygen saturation.
Acetazolamide↗
[REM sleep parasomnia].
The parasomnias consist of a heterogenous group of sleep behaviour disorders with different etiologies and various symptomatologies. By employing polysomnography and the simultaneous video recording of behaviour during sleep, it is possible to associate behavioral disturbances during sleep with specific sleep stages. In the present case study, a patient with a REM (rapid eye movement) sleep behaviour disorder is discussed. This rare form of parasomnia is characterized by motor enactment of vivid and striking dreams. Underlying disease in the present case involved bilateral lacunar ischemic infarcts in the brain stem. Under the combined psychotropic medication of carbamazepine and amitriptyline, the behaviour disorder during REM sleep remitted markedly.
Amitriptyline↗
Functional MR mapping of activated cortical areas.
Magnetic resonance imaging (MRI) has recently been demonstrated to be sensitive to changes in neuronal activity of cortical areas. We report our initial experiences with functional MR brain mapping at high spatial resolution using a conventional whole-body MR system. A total of 10 visual and motor cortex activation studies were carried out on 8 healthy volunteers. In each examination, a time course series of 15 strongly T2*-weighted FLASH images was measured from three adjacent slices. The image analysis revealed a subtle but highly significant signal increase in cortical layers of gray matter in primary and associative visual as well as sensorimotoric cortex regions during periods of excessive brain activity provoked by photic stimuli or motoric tasks, respectively. To correlate brain structure and brain function, the computed MR brain activation maps were directly superimposed on T1-weighted anatomic spin-echo images. With this advance into the area of functional neuroimaging, MRI is moving into an established domain of positron emission tomography (PET). We, therefore, discuss the advantages and limitations of the MR method in comparison to PET as far as this can be done at present.
Adult↗
[Intraspinal cartilaginous exostosis as the cause of a Brown-Séquard syndrome].
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Chondroma↗
[Bone marrow involvement in Hodgkin's disease: MR tomography and chemical-shift imaging].
The ranking of magnetic resonance imaging (MRI) and chemical shift imaging (CSI) of the bone marrow was assessed in 30 patients in the initial staging of Hodgkin's disease or in the restaging after relapse. The results were compared with other staging procedures, especially trephine biopsies. Pathologic findings were divided into diffuse and focal lesions resulting in a better differentiation between malignant infiltrations and unspecific marrow reactions that are common in Hodgkin's disease. Diffuse changes were unspecific, a diffuse marrow infiltration could not be established in 7 patients. Focal lesions proved to be infiltrations in 6 of 7 patients; only in one case an unspecific marrow reaction was found on histology. CSI showed a pathological increase of the relative water signal in focal and diffuse marrow changes, and made no individual diagnostic contribution.
Adolescent↗
[The contributions of magnetic resonance tomography to current problems of expertise. Muscle substance loss after trauma].
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Accidental Falls↗
[MR angiography of the vertebrobasilar circulatory area: the potential uses of the saturation technic to determine the direction of the flow].
MR angiography (MRA) combined with selective saturation techniques has proved to be a reliable method for the determination of flow direction and vascular supply at the level of the circle of Willis. We describe its application to the vertebrobasilar system (VBS) in ten volunteers and five patients with abnormal findings. In one patient with postsurgical stenosis of the brachiocephalic artery, reverse flow of the vertebral artery (VA) was demonstrated. Collateral blood flow from the anterior circulation over the posterior communicating arteries was shown in three patients with bilateral vertebral or proximal basilar artery occlusion. Due to increase of pressure during contrast injection into the contralateral VA, DSA showed reverse flow of a dissected VA in one patient. MR flow determination as well as TCD proved antegrade flow. All results correlated with both DSA and transcranial Doppler (TCD). The technique is little time consuming and is a promising add-on examination to conventional and MRA imaging of the VBS.
Adult↗