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F Gückel

Publications and source records attributed to F Gückel.

At least 37 records · Page 2Linked to original sources
PubMed1994

[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↗
PubMed1994

[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↗
PubMed1994

[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↗
PubMed1994

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↗
PubMed1993

[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↗
PubMed1992

[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↗
PubMed1992

[MR tomographic studies of the cerebral circulation: the methodological principles and initial clinical experiences with T2*-weighted gradient-echo sequences and CM administration as a bolus].

Paramagnetic contrast agents produce local magnetic field inhomogeneity when they pass through the cerebrovascular system. This effect can be monitored with T2*-weighted gradient echo images, which show transient signal loss, while a bolus of GdDTPA is passing through the brain tissue. This signal loss is correlated to the local cerebral tissue perfusion and the local cerebral blood volume. In a prospective study 10 volunteers and 14 patients with cerebral infarcts and brain tumours were examined. After bolus application of GdDTPA a dynamic series of rapid T2*-weighted gradient echo images were recorded, and the local dynamics of contrast flow in brain tissue was examined. From the series of images, local changes in signal intensity were calculated pixel by pixel and presented as parameter images. By this method, infarcted areas and brain tumours can be distinguished from normal tissue by their contrast flow dynamics. The abnormal contrast dynamics depend on changes in local tissue perfusion and alterations in local blood volume. The separation of the influence of both parameters however is still an unsolved problem.

Adolescent↗
PubMed1992

[MR tomography of the bone marrow in malignant systemic diseases. Diagnosis and therapeutic follow-up control].

This paper presents a short survey of the current status of bone marrow diagnosis in systemic neoplastic disease by means of MR imaging. The different patterns of bone marrow infiltration from lymphomas and leukaemias are presented and the differential diagnoses are discussed. Apart from the primary diagnosis the relevance of conventional MRI and chemical shift imaging for therapy follow up and after-care is discussed.

Bone Marrow↗
PubMed1991

Detection of bone marrow infiltration by non-Hodgkin's lymphoma--comparison of histological findings, analysis of gene rearrangements, and examination by magnetic resonance imaging.

The histological examination of bone marrow specimens is one of the standard procedures in staging non-Hodgkin's lymphoma. To investigate the validity of a conventional unilateral iliac crest biopsy, we performed a prospective study comparing histological findings with analysis of gene rearrangements in bone marrow samples and magnetic resonance imaging of bone marrow. Twenty-seven consecutive patients with non-Hodgkin's lymphoma (ten with high grade, seventeen with low grade) were studied. In twelve patients, histological examination revealed bone marrow infiltration. Results of histology and magnetic resonance imaging were discordant in three of the twenty-seven patients. With magnetic resonance imaging, suspected infiltration was found in two patients without histological evidence for bone marrow involvement in the disease. In one patient, an infiltration was described by histology but MRI revealed no pathological findings. In this case, DNA analysis confirmed bone marrow infiltration by detection of a clonal rearrangement of the immunoglobulin heavy chain gene. Analysis of gene rearrangements was performed in ten patients. As examined by histology, five of them had bone marrow involvement in the disease and five had not. In all these cases, analysis of gene rearrangements confirmed the histological findings. Our data show that, despite the small volume of bone marrow specimens, the sensitivity of an iliac crest biopsy seems to be high in staging non-Hodgkin's lymphoma.

Adult↗
PubMed1991

Assessment of bone marrow infiltration by magnetic resonance imaging in patients with hairy cell leukemia treated with pentostatin or alpha-interferon.

The bone marrow of five patients with progressive hairy cell leukemia was examined histologically and by magnetic resonance imaging in a prospective study. Iliac crest biopsies and magnetic resonance scans were performed before and after nine months of therapy with pentostatin (four patients) and alpha-interferon (one patient). T1-weighted scans were evaluated quantitatively and in terms of their visual appearance in three regions of interest (lumbar spine, pelvis and femur). In contrast to bone marrow histology, it was possible to detect differences in the degree of infiltration between these marrow regions in four patients by magnetic resonance imaging. After treatment, three patients had no residual bone marrow infiltration as determined histologically; in parallel, the magnetic resonance images had normalized. The remaining two patients achieved partial remission: marrow infiltration was estimated to be 20% histologically, corresponding well to the signal reduction obtained by magnetic resonance imaging. These data suggest that magnetic resonance imaging of the bone marrow is a sensitive method for assessing responses to treatment with pentostatin and alpha-interferon in patients with hairy cell leukemia.

Adult↗
PubMed1990

[MR-tomographic quantification of infiltrative bone marrow changes and therapeutic follow-up of patients with hairy cell leukemia].

The effect of treatment on bone marrow infiltration in hairy cell leukaemia was followed by means of MRT in five patients. A semi-quantitative method has been developed in order to judge the effect of treatment. The results correlate well with the findings on iliac crest biopsies. The method could partly replace the invasive iliac crest biopsies, which are used for therapy monitoring.

Bone Marrow↗
PubMed1990

Real-time follow-up of 5-fluorouracil metabolism in the liver of tumor patients by means of F-19 MR spectroscopy.

Intraarterial 5-fluorouracil (5-FU) chemotherapy in eight patients, one with primary and seven with secondary liver tumors, was monitored by means of in vivo fluorine-19 magnetic resonance (MR) spectroscopy. F-19 MR spectra were obtained with surface coils and included signal contributions from both liver and tumor tissue. The time course of the relative concentrations of 5-FU and its major catabolite, alpha-fluoro-beta-alanine (FBAL), was followed for up to 100 minutes after the start of drug administration. The time constants for the kinetics of 5-FU ranged from 8 to 75 minutes, whereas the time constants for FBAL were either approximately 15 or 50 minutes. A broad peak comprising nucleoside and nucleotide anabolites of 5-FU was detected in one patient. These investigations demonstrate the feasibility of short-term therapy monitoring with F-19 MR spectroscopy and that catabolites and anabolites of 5-FU can be observed separately. However, since no F-19 MR spectroscopy localization sequence is available at present, the contributions to the total MR signal from normal liver and tumor tissue cannot be discriminated.

Adult↗