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M Levivier

Publications and source records attributed to M Levivier.

At least 73 records · Page 4Linked to original sources
PubMed1994

PET in stereotactic conditions increases the diagnostic yield of brain biopsy.

We have recently described a technique allowing routine integration of PET scan data in the planning of stereotactic brain biopsy [Levivier et al:, Neurosurgery, 1992; 31:792-797]. We now report our results in a consecutive series of 38 patients that underwent combined FDG-PET and CT-guided stereotactic biopsy between June 1991 and January 1993. Stereotactic procedures were performed according to a standard protocol in which two biopsy trajectories were used whenever possible. This yielded to a total of 78 trajectories. In 31 patients, at least 1 trajectory was defined using an abnormality visualized on PET. The histological diagnosis was obtained in all cases. The diagnostic yield of each trajectory according to the FDG uptake of PET and contrast enhancement on CT showed that most low-grade tumors were found in hypometabolic/hypodense areas, glioblastomas were all diagnosed in areas with increased FDG uptake and contrast enhancement on CT while data for anaplastic astrocytomas were heterogeneously distributed. In the present series, 6 targets defined on CT were nondiagnostic; this never occurred when targets were defined on FDG-PET. In one case of anaplastic astrocytoma, the diagnosis was only made using a target defined on PET in a normal CT area; the second trajectory was made in a contrast-enhanced area on CT and was nondiagnostic. Because only structural images such as CT or MRI are available preoperatively, we analyzed separately the benefit of FDG-PET-guided biopsy in patients who have either an enhanced- or a nonenhanced lesion on CT. CT-enhanced lesions were found in 27 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
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

Striatal implants of fetal striatum or gelfoam protect against quinolinic acid lesions of the striatum.

Previous studies in our laboratory have shown that intrastriatal implants of fetal striatum significantly attenuate excitotoxic damage resulting from a 240 nmol quinolinic acid (QA) challenge delivered 7 days later. In contrast, animals with intrastriatal implants of other tissue types (adipose tissue, peripheral nerve or adrenal medulla) demonstrate a more limited, but consistent trend in protection from QA excitotoxicity. The present study was designed to test the hypothesis that partial striatal protection found in animals receiving peripheral tissue grafts is due to the transplantation procedure eliciting a host response which attenuates excitotoxicity. Adult female Long-Evans rats received either cellular (fetal striatum) or acellular (gelfoam) implants followed 1 week later by a unilateral injection of 240 nmol QA into the grafted striatum. Animals were tested for rotational asymmetries before grafting, post-implantation, and after lesioning. Compared to baseline rotational behavior, rats which received implants did not show changes in ipsilateral turning after QA lesions. This protective effect was not limited to rotational behavior since improvements in spontaneous locomotor activity were evident. In addition, the adipsia and aphagia often associated with striatal lesions were ameliorated in both groups of grafted animals. Morphometric analysis demonstrated that endogenous dopaminergic, cholinergic and enkephalinergic systems in the two transplanted groups sustained less excitotoxic damage than in the QA lesioned, non-grafted animals. These results are consistent with the hypothesis that a host generated response activated by the implantation procedure provides a protective effect against QA excitotoxicity.

Animals↗
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

Gadolinium enhancement of vertebral endplates following lumbar disc surgery.

Gadolinium enhancement may be normal in the vertebral endplates adjacent to previously operated intervertebral discs. To determine the frequency of this finding and to differentiate this normal healing process from early lesions due to focal infection, we studied 135 patients who had undergone surgery for herniated lumbar disc, and compared them with 249 unoperated patients with radicular symptoms and 15 with known spondylodiscitis. Hypointense foci which enhanced with gadolinium were identified in the endplates of 25 (18.5%) of the operated patients, 9 of whom required a second operation for recurrent disc herniation, at which time the absence of infection was confirmed. Gadolinium enhancement within the endplates adjacent to the operated disc occurs during normal healing after surgery. Care should be taken before invoking a diagnosis of focal infection or secondary spondylodiscitis.

Adult↗
PubMed1993

Characterization of nuclear DNA content, proliferation index, and nuclear size in a series of 181 meningiomas, including benign primary, recurrent, and malignant tumors.

The characterization of nuclear area, the proliferation index, and nuclear DNA content was carried out by means of digital cell image analysis, which makes it possible to compute morphometric and densitometric features on Feulgen-stained nuclei from archival, that is, formalin-fixed, paraffin-embedded materials. The 181 meningiomas studied included 173 classic (41 meningotheliomatous, 27 fibroblastic, 82 transitional, nine psammomatous, eight angiomatous and six hemangioblastic tumors) and eight malignant meningiomas (three hemangiopericytomas and five tumors that we labeled HFM, that is, tumors exhibiting evidence of histological features of malignancy). The results reveal a strong relationship between incomplete surgical resection and recurrence on the one hand and between the probability of recurrence and histopathological type on the other. Whereas neither nuclear area nor nuclear DNA content assessments were helpful in distinguishing the six classic and the two malignant meningioma subgroups, a statistically significant increase in proliferative activity was observed in the malignant meningiomas as compared with classic ones, excepting hemangioblastomas that proliferate at the same rate as the malignant meningiomas. Furthermore, the multiple meningiomas definitely proliferated more actively than the single ones, but a similar proliferative activity was observed in the nonrecurrent and recurrent meningiomas. Proliferation analyses might be therefore helpful for determining aggressive meningiomas and for planning adjuvant therapy in these cases.

Adult↗
PubMed1993

DNA histogram typing in a series of 707 tumors of the central and peripheral nervous system.

The diagnostic value of ploidy level was investigated in a series of 707 tumors (from 707 patients) of the central and peripheral nervous system. The series contained 91 nerve sheath tumors (NSTs), 222 meningiomas (MNGs), 37 primitive neuroectodermal tumors (PNETs), 293 glial tumors of the adult (ATTs), and 64 brain metastases (MTTs). The ploidy level of each tumor was obtained by means of its DNA histogram type (DHT), which was computed (digital cell image analysis) on Feulgen-stained nuclei from archival formalin-fixed paraffin-embedded materials. The data reveal that the measurement of the ploidy level showed a diagnostic value in some of these tumor cases. Indeed, the proportion of highly aneuploid cases significantly (p < 0.05-0.01) decreased according to the sequence PNETs (72%)-->MTTs (64%)-->ATTs (40%)-->NSTs (23%)-->MNGs (9%). Nevertheless, this significant diagnostic value in terms of a distinction between benignity and malignancy only appears when all the tumors are taken into consideration. Indeed, at the level of one individual patient, our study shows that, like traumatic neuromas, schwannomas, or classical meningiomas, completely benign tumors can exhibit a high aneuploidy level. In contrast, some tumors from histopathological groups like brain metastases or PNETs, which are known to be clinically aggressive, could be completely diploid.

Astrocytoma↗
PubMed1993

Assessment of nuclear size, nuclear DNA content and proliferation index in stereotaxic biopsies from brain tumours.

In this paper we study the feasibility of measuring the diverse biological parameters in stereotaxic biopsies from human brain lesions. These biological parameters are the nuclear area (NA), the proliferation index (PI) and the ploidy level, the latter of which was evaluated by means of the DNA index (DI) and histogram type (DHT). These parameters were assessed by means of the digital cell image analysis of Feulgen-stained nuclei. This analysis was performed on 124 samples from 22 computed tomography (CT)-guided stereotaxic biopsies. The data show that the methodology used here enables the above parameters to be assessed on small samples without limiting the classical anatomopathological diagnosis. The data also reveal that the DHT corresponded more accurately to the ploidy level in the sample analysed than the DI. Lastly, it appears that supratentorial astrocytic tumours of the adult, which constituted the majority of the cases analysed here, are strongly heterogeneous at a biological level.

Biopsy↗
PubMed1993

First year experience using the Fischer ZD-Neurosurgical Localizing Unit with particular reference to the development of PET-guided stereotactic biopsy.

Initial experience using the Fischer ZD-Neurosurgical Localizing Unit is reviewed. During the first year, 26 stereotactic procedures were performed in 25 patients. Twenty-two patients underwent imaging-guided stereotactic biopsy. Among them, 20 were included in the protocol we have developed for combined positron emission tomography (PET)- and computerized tomography (CT)-guided stereotactic biopsy. The technique is briefly described and preliminary results are reported. Most low-grade tumors were found in hypometabolic/hypodense areas, glioblastomas were all diagnosed in areas with increased FDG uptake and contrast enhancement on CT while data for anaplastic astrocytomas were heterogeneous. Some of the biopsic trajectories performed in areas were there was no increased FDG uptake or in areas with increased FDG uptake but without contrast enhancement on CT were non diagnostic. This never occurred in areas with both increased FDG uptake and contrast enhancement. Other stereotactic procedures performed include 2 catheter placement for drainage of cystic lesions, 3 stereotactically guided open neurosurgical procedures and 1 third ventriculostomy. Procedural objectives were accomplished in all cases. From our experience, we found stereotactic procedures using this system safe, accurate, easy to handle and allowing a wide range of applications. Because the system is designed to be readily used in conjunction with modern planar imaging techniques (i.e. CT and magnetic resonance imaging), it allowed us to develop a technique for PET-guided biopsy which might increase the diagnostic yield of stereotactic biopsy of intracranial neoplasms.

Adolescent↗
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↗
PubMed1992

A patient with two upper lumbar disc herniations.

Of all lumbar disc herniations, less than 5% occur in the upper lumbar area. Though protrusions are common at all levels, truly extruded disc herniations in the upper lumbar area from L1 to L3 are rare. Even more unusual is the multilevel occurrence of herniations in this area. The authors stress the importance of accurate diagnosis and clinically directed medical imaging work-ups.

Humans↗
PubMed1992

[Current therapeutic approach in Parkinson disease].

Parkinson's disease is a neurodegenerative disorder characterized mainly by a loss of the dopaminergic neurons of the nigrostriatal pathway. The symptomatic treatment, which consists of the supply of the deficient neurotransmitter dopamine, does not, however, prevent the progression of the disease and is frequently associated with major motor and psychiatric side effects. Recent basic and clinical investigations have led to the development of new therapeutical strategies for Parkinson's disease. The authors review and describe these new approaches which include: [1] treatments aimed at slowing down the progression of the disease, [2] treatments aimed at decreasing the motor side effects and [3] the use of intracerebral transplantations.

Antiparkinson Agents↗
PubMed1991

Sham transplantation protects against 6-hydroxydopamine-induced dopaminergic toxicity in rats: behavioral and morphological evidence.

Administration of the neurotoxin 6-hydroxydopamine (6-OHDA) to rat brain causes biochemical and neuroanatomical changes to the nigrostriatal dopaminergic pathway similar to those observed in Parkinson's disease (PD). Although the cause of PD is unknown, it has been hypothesized that the neurodegenerative changes seen in PD might result from exposure to a neurotoxin. Therefore, strategies for limiting neurotoxin-induced dopaminergic damages, like those caused by 6-OHDA, may be of both clinical and basic interest. Accordingly, we tested the ability of both fetal neural (striatum) and fetal non-neural (liver) tissue implants to protect the rat striatum against the toxic effects of a subsequent intrastriatal injection of 6-OHDA. Non-grafted rats (lesion only) showed amphetamine-induced rotational behavior and a decrease in striatal [3H]mazindol-labeled dopamine uptake sites after 6-OHDA injection. In contrast, the animals grafted with striatum or liver showed no behavioral or biochemical changes. Interestingly, sham-transplanted control animals were also protected against the 6-OHDA-induced toxicity. These results suggest that the resistance of the dopaminergic system against 6-OHDA neurotoxicity observed in grafted and sham-transplanted animals is likely to be related to the surgical procedure itself. This observation points to a possible role for surgery-related events in the clinical improvement described in PD patients who underwent intracerebral transplantation.

Analysis of Variance↗
PubMed1991

Neurotensin receptors in human meningiomas.

We have investigated the presence of neurotensin receptors in human meningiomas by in vitro binding autoradiography. Ten of the 12 meningiomas tested displayed specific [3H]neurotensin binding. All meningothelial (n = 3) and transitional (n = 5) meningiomas were positive, whereas only 2 of the 4 fibroblastic meningiomas showed measurable concentrations of neurotensin binding sites. Within the tumors, [3H]neurotensin binding was preferentially observed in syncytial areas. Saturation experiments showed that the maximal binding capacity (Bmax) greatly varied among tumors, ranging from low values to more than 290 fmol/mg of protein. All positive tumors had neurotensin binding sites with a dissociation constant (kd) within the nanomolar range and a pharmacological specificity for [3H]neurotensin similar to neurotensin receptors.

Adult↗
PubMed1991

Invading meningiomas of sphenoid wing. What must we know before surgery?

Sphenoid wing meningiomas are very invasive tumours. The only permanent treatment is total eradication. But quality of life should also be taken into account. Several surgical approaches have been proposed with more and more aggressivity. We have raised a list of 9 questions which is not exhaustive. We recommend solving them before surgery and to be sure to have an answer before a surgical decision is made. This would be of great benefit for more efficacious results with less sequelae.

Humans↗
PubMed1991

Three-quarter prone approach to the pineal-tentorial region. Report of seven cases.

We report our preliminary results (seven cases) with a three-quarter prone approach to the pineal-tentorial region using an opening beneath the midline. The technique we have used eliminates the risk of air embolism because the head is just over the right atrium, the table remaining in an horizontal plane. Using the natural effect of gravity, it is no more necessary to use retraction on the occipital lobe. So, hemianopsia is eliminated. We confirm the results of other teams who have used this approach which seems to us to be the best way to treat any lesion in the pineal-tentorial area.

Adult↗