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Biomedical subjects

Freimut D Juengling

Publications and source records attributed to Freimut D Juengling.

At least 19 recordsLinked to original sources
PubMed2006

Dose selection for radioiodine therapy of borderline hyperthyroid patients according to thyroid uptake of 99mTc-pertechnetate: applicability to unifocal thyroid autonomy?

PURPOSE: The aim of this study was to evaluate the feasibility of applying a previously described dose strategy based on (99m)Tc-pertechnetate thyroid uptake under thyrotropin suppression (TcTU(s)) to radioiodine therapy for unifocal thyroid autonomy. METHODS: A total of 425 consecutive patients (302 females, 123 males; age 63.1+/-10.3 years) with unifocal thyroid autonomy were treated at three different centres with (131)I, using Marinelli's formula for calculation of three different absorbed dose schedules: 100-300 Gy to the total thyroid volume according to the pre-treatment TcTU(s) (n=146), 300 Gy to the nodule volume (n=137) and 400 Gy to the nodule volume (n=142). RESULTS: Successful elimination of functional thyroid autonomy with either euthyroidism or hypothyroidism occurred at a mean of 12 months after radioiodine therapy in 94.5% of patients receiving 100-300 Gy to the thyroid volume, in 89.8% of patients receiving 300 Gy to the nodule volume and in 94.4% receiving 400 Gy to the nodule volume. Reduction in thyroid volume was highest for the 100-300 Gy per thyroid and 400 Gy per nodule strategies (36+/-19% and 38+/-20%, respectively) and significantly lower for the 300 Gy per nodule strategy (28+/-16%; p<0.01). CONCLUSION: A dose strategy based on the TcTU(s) can be used independently of the scintigraphic pattern of functional autonomous tissue in the thyroid.

Adult↗
PubMed2006

Brain activation during craving for alcohol measured by positron emission tomography.

OBJECTIVE: Craving for alcohol is probably involved in acquisition and maintenance of alcohol dependence to a substantial degree. However, the brain substrates and mechanisms that underlie alcohol craving await more detailed elucidation. METHOD: Positron emission tomography was used to map regional cerebral blood flow (CBF) in 21 detoxified patients with alcohol dependence during exposure to alcoholic and non-alcoholic beverages. RESULTS: During the alcohol condition compared with the control condition, significantly increased CBF was found in the ventral putamen. Additionally, activated areas included insula, dorsolateral prefrontal cortex and cerebellum. Cerebral blood flow increase in these regions was related to self-reports of craving assessed in the alcoholic patients. CONCLUSIONS: In this investigation, cue-induced alcohol craving was associated with activation of brain regions particularly involved in brain reward mechanisms, memory and attentional processes. These results are consistent with studies on craving for other addictive substances and may offer strategies for more elaborate studies on the neurobiology of addiction.

Adult↗
PubMed2006

Grey-matter abnormalities in boys with Tourette syndrome: magnetic resonance imaging study using optimised voxel-based morphometry.

The genesis of Tourette syndrome is still unknown, but a core role for the pathways of cortico-striatal-thalamic-cortical circuitry (CSTC) is supposed. Volume-rendering magnetic resonance imaging data-sets were analysed in 14 boys with Tourette syndrome and 15 age-matched controls using optimised voxel-based morphometry. Locally increased grey-matter volumes (corrected P < 0.001) were found bilaterally in the ventral putamen. Regional decreases in grey matter were observed in the left hippocampal gyrus. This unbiased analysis confirmed an association between striatal abnormalities and Tourette syndrome, and the hippocampal volume alterations indicate an involvement of temporolimbic pathways of the CSTC in the syndrome.

Adolescent↗
PubMed2005

Separating functional and structural damage in persistent vegetative state using combined voxel-based analysis of 3-D MRI and FDG-PET.

Functional and structural damage in postanoxic persistent vegetative state (PVS) was analysed using 18fluorodeoxyglucose PET (FDG-PET) coregistered to 3-D MRI in combination with morphometric 3-D MRI analysis (voxel-based morphometry, VBM). In five patients in late stages of non-traumatic PVS, combined analysis using statistical parametric mapping (SPM2) was performed to compare metabolic impairment and structural loss. FDG-PET showed widespread hypometabolism at p<0.001 (corrected) in the parietal, parietooccipital and frontotemporal cortices, cingulum, frontal medial and precentral gyrus, and within the bilateral thalamus. VBM revealed multilocal structural loss at p<0.001 (corrected) in the inferior parietal and superior/medial frontal cortices, insula and operculum, superior and medial temporal lobes, cingulum and fusiform gyrus, caudate, midbrain, dorsal pons, and the cerebellum, but to a lesser extent in the thalamus. The selective vulnerability of the brain in a sample of PVS patients could be mapped in vivo, indicating that a complex structural and functional lesion pattern of the cerebral networks seems to be associated with this condition.

Adult↗
PubMed2005

Comparison of voxel-based 3-D MRI analysis and subtraction ictal SPECT coregistered to MRI in focal epilepsy.

While voxel-based 3-D MRI analysis methods as well as assessment of subtracted ictal versus interictal perfusion studies (SISCOM) have proven their potential in the detection of lesions in focal epilepsy, a combined approach has not yet been reported. The present study investigates if individual automated voxel-based 3-D MRI analyses combined with SISCOM studies contribute to an enhanced detection of mesiotemporal epileptogenic foci. Seven consecutive patients with refractory complex partial epilepsy were prospectively evaluated by SISCOM and voxel-based 3-D MRI analysis. The functional perfusion maps and voxel-based statistical maps were coregistered in 3-D space. In five patients with temporal lobe epilepsy (TLE), the area of ictal hyperperfusion and corresponding structural abnormalities detected by 3-D MRI analysis were identified within the same temporal lobe. In two patients, additional structural and functional abnormalities were detected beyond the mesial temporal lobe. Five patients with TLE underwent epileptic surgery with favourable postoperative outcome (Engel class Ia and Ib) after 3-5 years of follow-up, while two patients remained on conservative treatment. In summary, multimodal assessment of structural abnormalities by voxel-based analysis and SISCOM may contribute to advanced observer-independent preoperative assessment of seizure origin.

Adult↗
PubMed2004

Thalamic atrophy in Huntington's disease co-varies with cognitive performance: a morphometric MRI analysis.

The pattern of motor, behavioral and cognitive symptoms in Huntington's disease (HD) implicates dysfunction of basal-ganglia-thalamo-cortical circuits. This study explored if cognitive performance in HD is correlated with localized cerebral changes. Psychomotor functions were investigated by verbal fluency, Stroop color word and Digit Symbol tests in 44 HD patients and 22 controls. Three-dimensional magnetic resonance imaging (MRI) data were analyzed with regard to regional gray matter changes by use of the observer-independent whole-brain-based approach of voxel-based morphometry (VBM). Using statistical parametric mapping, the MRI data of the HD patients were analyzed in an ANCOVA including the individual results of the neuropsychological tests. Besides striatal areas, symmetrical regional atrophy of the thalamus was found to co-vary significantly with cognitive performance (P < 0.001, corrected for multiple comparisons). In particular, thalamic subnuclei projecting to prefrontal areas (dorsomedial subnucleus) and connected to the striatum (centromedian/parafascicular and ventrolateral nuclear complex) displayed volume loss, in agreement with neuropathological studies. These results suggest that thalamic degeneration contributes in an important way to the impairment of executive function in early HD. Patients who are impaired in executive tests display structural double lesions of the basal-ganglia-thalamo-cortical circuitry both at the striatal and at the thalamic level.

Adult↗
PubMed2004

Global cerebral atrophy in early stages of Huntington's disease: quantitative MRI study.

Global brain atrophy was determined in 70 patients suffering from Huntington's disease (HD) and 70 healthy controls, using brain parenchymal fractions calculated from 3D MRI data in a standardized procedure. In HD patients, brain parenchymal fractions were significantly reduced compared to controls in all age groups; the physiological decline with age was less pronounced in HD. However, brain parenchymal fraction values did not allow the prediction of clinical impairment (as assessed by clinical scores). Global brain parenchyma reduction seems to be an early or even constitutional feature of HD, but clinical symptoms appear to reflect regional rather than global atrophy. Overall, MRI-based brain volume quantification correlated with clinical scores clarifies the functional impact of morphological brain alterations.

Adolescent↗
PubMed2004

18FDG-PET in epilepsies of infantile onset with pharmacoresistant generalised tonic-clonic seizures.

AIMS: To investigate the pathophysiology of pharmacoresistant epilepsies with cryptogenic generalised tonic-clonic seizures (GTCS) from infancy. METHODS: 18F-Deoxy-Glucose-Positron Emission Tomography 18FDG-PET) with statistical parametric mapping (SPM). Inclusion criteria were: pharmacoresistant chronic epilepsy with GTCS commencing in infancy, no focal seizures except alternating hemiconvulsions and no focal epileptic discharges in the EEG during the first year of the disease, no focal changes upon routine neuroradiological investigations, no indication of brain damage according to history and clinical examination. RESULTS: 15 boys and 15 girls with a mean age of 6.4 years (range l-14 years) were included. All still suffered from seizures despite past treatment with a mean of five drugs. Nearly all were mentally retarded, 19 to a severe and 10 to a minor degree. Fifteen were ataxic and 11 hypotonic. The EEG in 23 showed irregular generalised spike-wave discharges. PET SPM analysis revealed bioccipital hypometabolism related to sedation. Pathological monofocal hypometabolic areas were found in three, multifocal hypometabolic areas in 22 and diffuse bilateral hypometabolism in three patients. Frontal hypometabolism correlated to the degree of mental retardation, hypotonia, and ataxia. Temporomesial hypometabolism correlated to the occurrence of obtunded states and prominent delta rhythms in the EEG. Central and parietal changes were associated with the occurrence of myoclonic seizures and spike-wave discharges. CONCLUSIONS: 18FDG-PET in many of these children with cryptogenic generalised epilepsies showed multifocal hypometabolic areas of unknown aetiology. Primary cortical microdysgenesis and secondary changes due to the severe and long-standing epilepsy must be considered. Only a minority of patients showed restricted focal hypometabolism as a possible indication for surgical treatment.

Adolescent↗
PubMed2003

Quantification of brain atrophy in patients with myotonic dystrophy and proximal myotonic myopathy: a controlled 3-dimensional magnetic resonance imaging study.

Myotonic dystrophy (DM1) and proximal myotonic myopathy (PROMM or DM2) are two distinct muscular disorders with multisystemic involvement. Both have previously been reported to be associated with cognitive impairment and white matter lesions detected by cerebral magnetic resonance imaging (MRI). In this study, the extent of brain atrophy was investigated in vivo in ten DM1 and nine PROMM patients in comparison to age-matched healthy controls for each group. The diagnosis was confirmed by DNA analysis of all patients. As a quantitative marker, the ratio of brain parenchymal to intracranial volume, called brain parenchymal fraction (BPF), was calculated from 3-dimensional MRI data using an automated analysis technique. Compared to age-matched healthy controls (mean BPF 0.852 +/- 0.032), the BPF in DM1 patients (0.713 +/- 0.031) was highly significantly decreased (P < 0.001). In contrast, the PROMM patients (mean BPF 0.792 +/- 0.029) showed only slightly decreased BPF values (P < 0.05). BPF was not significantly correlated to any of the clinical or genetic parameters in both diseases (disease duration, motor score, educational level, and number of CTG repeats in the expanded allele). In summary, global brain atrophy was demonstrated to occur in both diseases, but was more severely manifestated in DM1 patients.

Adolescent↗
PubMed2003

Activation of a residual cortical network during painful stimulation in long-term postanoxic vegetative state: a 15O-H2O PET study.

Survivors of prolonged cerebral anoxia often remain in the persistent vegetative state (PVS). In this study, long-term PVS patients were investigated by 15O-H(2)O PET to analyze their central processing of pain. The study was approved by the local Ethics Committee, the experiments were performed in accordance with the Helsinki Declaration of 2000. Seven patients remaining in PVS of anoxic origin for a mean of 1.6 years (range 0.25-4 years) were investigated. We performed functional PET of the brain using 15O-labelled water during electrical nociceptive stimulation. Additionally, a brain metabolism study using 18F-fluorodeoxyglucose (FDG) PET and multi-sequence MRI (including a 3-D data set) were acquired in all patients. PET data were analyzed by means of Statistical Parametric Mapping (SPM99) and coregistered to a study-specific brain template. MRI and FDG PET showed severe cortical impairment at the structural and the functional level, that is, general atrophy of various degrees and a widespread significant hypometabolism, respectively. Pain-induced activation (hyperperfusion) was found in the posterior insula/secondary somatosensory cortex (SII), postcentral gyrus/primary somatosensory cortex (SI), and the cingulate cortex contralateral to the stimulus and in the posterior insula ipsilateral to the stimulus (P<0.05, small-volume-corrected). No additional areas of the complex pain-processing matrix were significantly activated. In conclusion, the regional activity found at the cortical level indicates that a residual pain-related cerebral network remains active in long-term PVS patients.

Adult↗
PubMed2003

Age-related brain parenchymal fraction is significantly decreased in young multiple sclerosis patients: a quantitative MRI study.

The extent of brain atrophy was determined in 33 patients with multiple sclerosis (MS) and in 60 healthy subjects (21-76 years) by calculating brain parenchymal fractions (BPF, the ratio of brain parenchymal to intracranial volume) from 3D MRI. Within the normal data base, subjects at higher ages showed significantly lower BPF values. In younger MS patients, BPF was significantly decreased compared with age-matched controls (20-29 years, p= 0.0022; 30-39 years, =p 0.0001; 40-49 years,p = 0.0444) and was significantly correlated with disease duration and disease severity, but not with the number of detectable MS lesions. Determination of age-related BPF demonstrated significant brain atrophy in early MS and can be considered as a useful biological marker for monitoring MS.

Adult↗
PubMed2003

High social desirability and prefrontal cortical activity in cancer patients: a preliminary study.

BACKGROUND: Social desirability is sometimes associated with poor prognosis in cancer patients. Psycho-neuro-immune interaction has been hypothesized as an underlying mechanism of the negative clinical outcome. Purpose of this study was to examine possible effects of high social desirability on the regional brain activity in patients with malignant diseases. MATERIAL/METHODS: Brain metabolism of 16 patients with various malignant diseases was measured by PET with 18F-fluorodeoxyglucose (FDG). Patients were divided into 2 groups using median split on Marlowe & Crown's Social Desirability Scale (MC), controlling for age, gender, and for severity of depression and anxiety, the possible two major influential factors. A group comparison of the regional cerebral activity was calculated on a voxel-by-voxel basis using statistical parametric mapping (SPM). RESULTS: The subgroup comparison showed that the high social desirability was associated with relatively increased metabolism in the cortical regions in the prefrontal, temporal and occipital lobes as well as in the anterior cingulate gyrus. CONCLUSIONS: High social desirability seems to be associated with increased activity in the prefrontal and other cortical areas. The finding is in an accordance with previous studies that demonstrated an association between prefrontal damage and anti-social behavior. Functional neuroimaging seems to be useful not only for psychiatric evaluation of major factors such as depression and anxiety but also for further psychosocial factors in cancer patients.

Adult↗
PubMed2002

Cerebral regional hypometabolism caused by propofol-induced sedation in children with severe myoclonic epilepsy: a study using fluorodeoxyglucose positron emission tomography and statistical parametric mapping.

Cerebral positron emission tomography (PET) in children often requires sedation. This study evaluated sedation-associated effects on cerebral glucose metabolism in 30 children with severe myoclonic epilepsy as investigated by cerebral (18)F-fluorodeoxyglucose (FDG)-PET. Prior to the PET acquisition, 24 children underwent propofol sedation. Pixel-based t-statistics were calculated using statistical parametric mapping (SPM99) for comparisons of the patients' PET scans with both a healthy adult control group and an age-matched child intra-group control. In both analyses, statistically significant hypometabolic areas were found in the medial parieto-occipital cortex bilaterally, including the lingual gyrus, cuneus, posterior cingulate and middle occipital gyrus in all sedated children. All these localizations correlated in a covariate analysis with the injected dose of propofol (P<0.01, corrected). The bilateral parieto-occipital hypometabolism is likely to be a sedation-specific effect and should be taken into account when evaluating cerebral FDG-PET scans in sedated children.

Adolescent↗
PubMed2002

Thalamic gray matter changes in unilateral Parkinsonian resting tremor: a voxel-based morphometric analysis of 3-dimensional magnetic resonance imaging.

The thalamus is assumed to be involved in the generation of Parkinsonian tremor. Ten patients with tremor-dominant idiopathic Parkinson's disease (IPD) and strictly unilateral resting tremor were investigated by cerebral high-resolution 3-dimensional magnetic resonance imaging (MRI). MRI data were analyzed by an observer-independent morphometric technique, voxel-based morphometry (VBM). For VBM, MRI data were automatically normalized and segmented, then gray matter volumes were analyzed on a voxel-by-voxel basis in comparison to an age-matched control group using Statistical Parametric Mapping (SPM99). Highly significant structural changes, i.e. locally increased gray matter concentrations (P<0.001), were found in the nucleus ventralis intermedius (VIM) of the thalamus contralateral to the tremor side and were significantly covariant with tremor amplitudes. On the one hand, these changes were localized in close vicinity to a thalamic focal hypermetabolism as revealed by a previous positron emission tomography study in unilateral Parkinsonian tremor patients. On the other hand, the localization of the focal structural changes in VIM corresponds with the generally accepted target area of tremor surgery in IPD.

Aged↗
PubMed2002

SMART-PET: multimodality white matter imaging and display without loss of quantitative information.

PURPOSE: To improve analysis of cerebral white matter (WM) in fluoro-deoxy-glucose positron emission tomography (PET) images. MATERIALS AND METHODS: A multimodality analysis technique (segmented MRI and registered Talairach-transformed PET [SMART-PET]) was used for quantitative assessment of WM metabolism. Data processing included Talairach transformation of three-dimensional magnetic resonance imaging (MRI) and subsequent automated segmentation and coregistration to normalized PET images. Color model transformations were used for combined display: the hue saturation value color model was regarded as a three-dimensional data matrix, integrating quantitative voxel data of both modalities. The technique was applied in normal subjects and in patients suffering from different WM diseases. Regional analysis was performed to classify metabolic impairment on a five-point scale. RESULTS: Using SMART-PET, a considerable gain in image contrast for WM was achieved in all cases. In the normal subjects, WM metabolism was shown to be homogeneously unimpaired. Sum scores of regional analysis revealed metabolic WM changes in all patients. Extent of WM hypometabolism exceeded the extent of the lesions as delineated by MRI signal changes. CONCLUSION: The potential of the method for further elucidation of the role of WM diseases in brain dysfunction in patients is discussed.

Brain↗