Evaluation of a multicentre study with Iomazenil - a benzodiazepine receptor ligand

Schubiger, P. A.; Hasler, P. H.; Beer-Wohlfahrt, H.; Bekier, A; R, Oettli; Cordes, Michael; Ferstl, F. J.; Deisenhammer, E; Roo, M. De; Moser, Ewald; Nitzsche, Egbert U.; Podreka, I.; Riccabona, G; Bangerl, I.; Schober, O.; Bartenstein, Peter; Rijk, P. Van; Isselt, J. W. Van; Royen, E. A. Van; Verhoeff, N. P. L. G.; Haldemann, R; Schulthess, Gustav K. von

doi:10.1097/00006231-199107000-00002

Cited by 47 publications

(10 citation statements)

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“…The minimal information published so far suggests that SPECT with the potent benzodiazepine receptor antagonist iomazanil provides highly comparable localizing information to HMPAO SPECT (Beer et al, 1990;Van Huffelin et al, 1990; Bartenstein et al, 1991). Results of a multicenter study found it, in fact, to be far superior to HMPAO, but did not provide sufficient detail with respect to lobes of localization to comment further (Schubiger et al, 1991).…”

Section: Iomazanil Spectmentioning

confidence: 99%

The Relative Contributions of MRI, SPECT, and PET Imaging in Epilepsy

1994

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Functional and structural neuroimaging techniques are increasingly indispensable in the evaluation of epileptic patients for localization of the epileptic area as well as for understanding pathophysiology, propagation, and neurochemical correlates of chronic epilepsy. Although interictal single photon emission computed tomography (SPECT) imaging of cerebral blood flow is only moderately sensitive, ictal SPECT markedly improves yield. Positron emission tomography (PET) imaging of interictal cerebral metabolism is more sensitive than measurement of blood flow in temporal lobe epilepsy. Furthermore, PET has greater spatial resolution and versatility in that multiple tracers can image various aspects of cerebral function. Interpretation of all types of functional imaging studies is difficult and requires knowledge of time of most recent seizure activity and structural correlates. Only magnetic resonance imaging (MRI) can image the structural changes associated with the underlying epileptic process, and quantitative evidence of hippocampal volume loss has been highly correlated with seizure onset in medial temporal structures. Improved resolution and interpretation have made quantitative MRI more sensitive in temporal lobe epilepsy, as judged by pathology. When judged by electroencephalography (EEG), ictal SPECT and interictal PET have the highest sensitivity and specificity for temporal lobe epilepsy; these neuroimaging techniques have lower sensitivity and higher specificity for extratemporal EEG abnormalities. Regardless of the presence of structural abnormalities, functional imaging by PET or SPECT provides complementary information. Ideally these techniques should be used and interpreted together to improve the localization and understanding of epileptic brain.

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Section: Iomazanil Spectmentioning

confidence: 99%

The Relative Contributions of MRI, SPECT, and PET Imaging in Epilepsy

1994

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“…Benzodiazepine receptors 123 I-Ro16-0154 ( 123 I-iomazenil) was shown to have intracerebral retention parallel to the known distribution of benzodiazepine receptors (BZR) in man 97 . In comparative studies of HMPAO and 123 I-iomazenil SPECT, most subjects show concordant regions of reduced uptake with both tracers; some studies show a small difference in sensitivity, a more marked reduction or a more restricted area of reduced tracer uptake with 123 I-iomazenil [98][99][100][101][102][103] . These studies suggest little advantage in imaging BZR over blood flow.…”

Section: Cerebral Blood Flow Tracersmentioning

confidence: 99%

CPD – Education and Self-assessment: Functional imaging in epilepsy

Richardson

2001

Seizure

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Functional imaging plays a growing role in the clinical assessment and research investigation of patients with epilepsy. This article reviews the literature on functional MRI (fMRI) investigation of EEG activity, fMRI evaluation of cognitive and motor functions, magnetic resonance spectroscopy (MRS), single photon emission computed tomography (SPECT) and positron emission tomography (PET) in epilepsy. The place of these techniques in clinical evaluation and their contribution to a better neurobiological understanding of epilepsy are discussed.

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“…[123I]Iomazenil was prepared by iododestannylation of ethyl 7-(tributylstannyl)-5,6-dihydro-5-methyl-6-oxo-4H-imidazol[ 1,5-a] [ 1,4]benzodiazepine-3-carboxylate with chloramine-T in methanolic acetic acid at 120°C [12]. Radiolabeled products were purified by reversed phase HPLC (C-18 column, 3.9 x 300, 55% CH3OH/H20, 0.7 ml/min; R t 9.2 rain], formulated in 5% ethanol in normal saline containing 0.1 mM Lascorbic acid, pH 5-6, and filtered through a 0.2-gm membrane filter into a sterile 10-ml serum vial or sterile 10-ml syringe.…”

Section: Synthesis Of [123i]lomazenilmentioning

confidence: 99%

“…The multicenter trial of [~23I]iomazenil in 89 patients with epilepsy analyzed a single image at 30 min post injection (p.i.) of the tracer [4]. This time was selected because in coincided with maximal uptake in most cortical regions, which was reported to be 25-30 rain by Woods et al [5].…”

Section: Introductionmentioning

confidence: 99%

Dual-isotope autoradiographic measurement of regional blood flow and benzodiazepine receptor availability following unilateral middle cerebral artery occlusion

et al. 1994

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Single-photon emission tomography (SPET) imaging in patients with complex partial epilepsy has shown that the seizure focus is characterized by both decreased interictal blood flow and decreased uptake of the benzodiazepine (BZ) receptor tracer iodine-123 iomazenil. The purpose of this study was to examine the confounding effect of decreased flow on iomazenil uptake. The left middle cerebral artery of four rats was occluded, and the animals were simultaneously injected with 25 microCi of iodine-125 iomazenil and 500 microCi of the blood flow tracer [123I]iofetamine (N-isopropyl-p-iodoamphetamine). All rats, including two sham, were sacrificed 1 h after injection, a time when uptake of both agents is nearly maximal. Control experiments showed that arterial occlusion for 1 h did not affect the total number of BZ binding sites. Using a dual autoradiographic technique, the uptake of both [123I]iofetamine and [125I]iomazenil was measured in more than 200 regions showing variable levels of reduced flow and expressed as a percentage of the contralateral homotypic area. The straight line fit of % [125I]iomazenil (y axis) versus % [123I]iofetamine (x axis) in all 200 regions had a slope of 0.74. Insofar as the rat is an accurate model of human subjects with epilepsy, these studies suggest that decreased flow to the epileptogenic focus will linearly exacerbate the decrease in uptake secondary to neuropathologic loss of BZ receptors. Thus, for localization of seizure focus, a single SPET image of [123I]iomazenil in an epileptic patient may have greater sensitivity than a comparable blood flow image, because the former is enhanced by both decreased flow and a loss of BZ receptors.

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Evaluation of a multicentre study with Iomazenil - a benzodiazepine receptor ligand

Cited by 47 publications

References 0 publications

The Relative Contributions of MRI, SPECT, and PET Imaging in Epilepsy

The Relative Contributions of MRI, SPECT, and PET Imaging in Epilepsy

CPD – Education and Self-assessment: Functional imaging in epilepsy

Dual-isotope autoradiographic measurement of regional blood flow and benzodiazepine receptor availability following unilateral middle cerebral artery occlusion

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