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J Hildebrand

Publications and source records attributed to J Hildebrand.

At least 73 records · Page 4Linked to original sources
PubMed1995

Diagnostic yield of stereotactic brain biopsy guided by positron emission tomography with [18F]fluorodeoxyglucose.

The aim of the present study was to determine whether routine integration of positron emission tomography (PET) with 18F-labeled fluorodeoxyglucose (FDG) in the planning of stereotactic brain biopsy increases the technique's diagnostic yield. Forty-three patients underwent combined FDG-PET- and computerized tomography (CT)-guided stereotactic biopsy of intracranial lesions according to a previously described technique. In 36 patients, an area of abnormal FDG uptake was used to guide at least one stereotactic biopsy trajectory. A total of 90 stereotactic trajectories were performed; among them, 55 were based on FDG-PET-defined targets and 35 were based on CT-defined targets. Histological diagnosis was obtained in all patients, but six of the 90 trajectories were nondiagnostic; all six were based on targets defined by CT only. Differences between the diagnostic yield of trajectories based on FDG-PET-defined targets and those based on CT-defined targets were statistically significant in patients with contrast-enhanced lesions, but not in patients with nonenhancing lesions. These results support the view the FDG-PET may contribute to the successful management of brain tumor patients requiring stereotactic biopsy. Because no significant increase in discomfort or morbidity related to the technique was found, it is suggested that the development of similar techniques integrating PET data in the planning of stereotactic biopsy should be considered by centers performing stereotactic surgery and having access to PET technology.

Adolescent↗
PubMed1994

Acute effect of carmustine on glucose metabolism in brain and glioblastoma.

BACKGROUND: Adjuvant chemotherapy benefits a minority of patients with recurrent glioblastoma; a critical question therefore is how to select such responders. Metabolic reaction of the tumor, studied by positron emission tomography (PET) with [18F]-fluoro-2-deoxy-D-glucose (FDG), may be a suitable test of tumor responsiveness. In an effort to evaluate their prognostic value, the early effects of carmustine on brain and recurrent glioblastoma glucose metabolism were studied. METHODS: Positron emission tomography with [18F]fluoro-2-deoxy-D-glucose was used to study 10 patients with recurrent glioblastoma before and 24 hours after a first dose of carmustine (120 mg/m2). Absolute quantification of glucose metabolism was obtained, and metabolic changes were analyzed and confronted with survival duration. RESULTS: The mean ratios of pre- to postchemotherapy values were 0.98 +/- 0.06 (range, 0.90-1.06) for the cortex and 0.97 +/- 0.06 (range, 0.89-1.09) for the white matter. There was no statistical difference between pre- and post-chemotherapy metabolism. In the glioblastoma, individual ratios of pre- to postchemotherapy values were considerably more scattered than in the nonneoplastic tissues, ranging from 0.76 to 1.51. A significant positive correlation (P < 0.002) was found between post- to pre-chemotherapy ratios of glucose metabolism and survival length. CONCLUSIONS: In patients with recurrent glioblastoma, the first administration of carmustine produces no acute change of glucose metabolism in the noninvolved cerebral tissues. Acute changes of glucose metabolism in tumor tissue in response to this treatment varied, and a hypermetabolic reaction possibly predicts longer survival.

Adult↗
PubMed1994

Adjuvant therapy with dibromodulcitol and BCNU increases survival of adults with malignant gliomas. EORTC Brain Tumor Group.

OBJECTIVE: We tested adjuvant chemotherapy combining dibromodulcitol (DBD) and bischloroethylnitrosourea (BCNU) given postoperatively to adults with newly diagnosed supratentorial malignant gliomas. METHODS: We enrolled 269 patients, 255 of whom were eligible. After surgery, we treated all patients with radiation therapy, using a median dose of 60 Gy given in 30 fractions. After randomization, patients in the chemotherapy group also received (1) six weekly courses, administered during irradiation, of DBD 700 mg/m2 and (2) one to nine (median, four) courses, administered during the first year following radiation therapy, of DBD 1,000 mg/m2 on day 1 and BCNU 150 mg/m2 on day 2, with the course being repeated every 6 weeks. RESULTS: Patients treated with radiation therapy along with DBD plus BCNU (group 2) had significantly longer survival time (p = 0.044) and time to progression (p = 0.003) than did those treated with radiation therapy alone (group 1). The median survival time was 13.0 months for group 2 and 10.4 months for group 1; the median time to progression was 8.1 months for group 2 and 6.7 months for group 1. The percentage of patients alive at 18 and 24 months was 34% and 21% in group 2 compared with 21% and 12% in group 1. CONCLUSION: DBD plus BCNU is an effective adjuvant therapy for malignant glioma.

Adult↗
PubMed1994

Focal adhesion kinase: structure and signalling.

Studies on the attachment and spreading of cells in culture have provided valuable insights into the mechanisms by which cells transmit information from the outside to the inside of the cell. This brief review considers recent information on the role of focal adhesion-associated protein tyrosine kinases in integrin-regulated cell signalling.

Amino Acid Sequence↗
PubMed1994

Carbon-11-methionine and fluorine-18-FDG PET study in brain hematoma.

Three patients were examined using PET with L-methyl-11C-methionine (11C-methionine) and 2-18F-fluoro-2-deoxy-D-glucose (FDG) 20 to 32 days after the occurrence of nontumoral brain hematomas. PET revealed high uptake of 11C-methionine in the area surrounding the hematoma in all three patients. In two patients, discrete spots of moderate uptake of FDG were found at the periphery of a hypometabolic area. PET studies were repeated in two patients 76 and 103 days after the bleeding, respectively, and showed a dramatic decrease in 11C-methionine uptake around the hematoma. The spots of FDG uptake disappeared on the repeated late scans. We hypothesize that the subacute gliotic reaction surrounding brain hematomas is responsible for increased uptake of 11C-methionine and for the presence of spots of FDG uptake. PET studies with 11C-methionine and FDG performed 20 to 32 days after the initial symptom are not helpful in the differentiation between neoplastic and non-neoplastic origins of an intracerebral hemorrhage since tracer uptake at the periphery of the lesion may be increased in both.

Acute Disease↗
PubMed1993

Brain glucose metabolism and dopamine D2 receptor analysis in a patient with hemiparkinsonism-hemiatrophy syndrome.

We report findings on brain glucose metabolism and dopamine D2 receptors generated by positron emission tomography (PET) in a 67-year-old woman with right hemiparkinsonism-hemiatrophy syndrome (HP-HA). PET with [18F]-fluorodeoxyglucose (FDG) showed marked glucose metabolism asymmetry. There were significant reductions in glucose uptake at the level of the basal ganglia and, to lesser extent, in the fronto-parietal cortex contralateral to the clinically involved side. These changes were different from those found in a patient with hemi-Parkinson's disease who was scanned under similar conditions. Because the patient with HP-HA had only minimal response to levodopa therapy, we evaluated post-synaptic dopaminergic structures using PET with [18F]-fluoroethylspiperone (FESP). No striatal binding asymmetry was found in FESP/PET, which suggests a sparing of striatal dopamine D2 receptors. The changes in FDG uptake which we found were in brain areas relevant to the clinical features of HP-HA syndrome. In addition, our study provides evidence that FDG/PET may help to differentiate HP-HA syndrome from hemi-Parkinson's disease. In most instances, since HP-HA is associated with a more benign clinical course than Parkinson's disease, this distinction is of clinical important.

Aged↗
PubMed1993

Indications for stereotactically-aided differential diagnosis: the neurologist's view.

The contribution of stereotactic biopsy (SB) in three pathological conditions; neoplastic disease, immunodeficiency states and degenerative cerebral atrophy, is reviewed. When craniotomy is contraindicated, SB is the most reliable method for demonstrating the neoplastic nature and the degree of malignancy of an intracranial space occupying lesion and may help to delineate it limits. In immunodepressed patients, SB is frequently used to differentiate tumours from opportunistic infections. In degenerative dementia, SB is susceptible of differentiating Alzheimer's disease from other degenerative conditions.

AIDS Dementia Complex↗
PubMed1993

Positron emission tomography and histopathology in Creutzfeldt-Jakob disease.

We studied a 62-year-old man with Creutzfeldt-Jakob disease (CJD), using positron emission tomography (PET) and (18F)-2-fluoro-2-deoxy-D-glucose (FDG). Glucose metabolism was heterogeneously decreased throughout the brain. At autopsy, regional distributions of spongiosis, astrogliosis, and neuronal loss correlated with premortem regional metabolic deficits. These results suggest that PET with FDG may provide metabolic regional markers for CJD neuropathology.

Brain↗
PubMed1992

Supportive care of neurologic complications.

Approximately one cancer patient in five will suffer from injuries to either the central or peripheral nervous system. These complications occur preferentially in the advanced stages of neoplastic disease, and their management is an important aspect of the supportive care of these patients. The most common neurologic complications seen in patients with cancer are related to metastases or to local tumor spread. Antineoplastic treatments, mainly chemotherapy or radiotherapy, account for more than 10% of these complications. A much smaller percentage (probably less than 1%) are paraneoplastic manifestations. In this review, we discuss the most recent developments in the management of neurologic complications specifically related to cancer as well as some less specific problems such as thromboembolic complications and the use of steroids.

Adrenal Cortex Hormones↗
PubMed1992

Variations of homovanillic acid levels in ventricular cerebrospinal fluid.

We studied the nycterohemeral variations of homovanillic acid (HVA) in ventricular cerebrospinal fluid (CSF) in 24 patients undergoing monitoring of intracranial pressure as part of the normotensive hydrocephalus (NTH) work-up. CSF samples were obtained every 4 h in each patient. The mean individual values of HVA in the ventricular CSF ranged from 133 to 421 ng/ml, and they could not be correlated to any clinical feature. The intraindividual levels of HVA were stable throughout 24 hours, with a variation coefficient inferior to 10% in 63% of cases, and inferior to 20% in all the patients.

Aged↗
PubMed1992

Positron emission tomography-guided stereotactic brain biopsy.

We describe a technique that allows target definition for stereotactic brain biopsy using coordinates calculated on stereotactic positron emission tomographic (PET) images. In this study, PET images were obtained using [18F]-labeled fluorodeoxyglucose, a marker for glucose metabolism. The difference between PET-calculated and actual stereotactic coordinates of simulated targets is within PET spatial resolution. Combined computed tomography- and PET-guided stereotactic biopsies were performed in 11 patients with brain tumors. In this report, we describe two representative patients who underwent stereotactic brain biopsy using the present technique. Because of the complementary role of PET and computed tomography, their integration in multimodality planning might optimize the target selection for stereotactic brain biopsies.

Astrocytoma↗
PubMed1991

Focal neurological deficit with sudden onset as the first manifestation of sarcoidosis: a case report with MRI follow-up.

Stroke as a presenting manifestation of sarcoidosis has rarely been reported. This contrasts with the frequent anatomopathological findings of cerebrovascular involvement in neurosarcoidosis. We present a patient who developed acutely a right brachiofacial weakness and dysarthria. Pulmonary sarcoidosis was found. A brain CT and magnetic resonance imaging (MRI) scan disclosed multiple bilateral ischemic, mainly subcortical lesions. Despite a favorable clinical evolution under adequate corticotherapy, an MRI performed 3 months later showed an increased number of the previously observed lesions. This observation suggests that in some cases the evolution of central nervous system sarcoid lesions occurs independently from corticotherapy, and that MRI, in spite of its known great sensitivity in detecting those lesions, may not play a role in the follow-up of some patients with neurosarcoidosis.

Adult↗