Influence of technetium-99m-hexamethylpropylene amine oxime injection time on single-photon emission tomography perfusion changes in epilepsy.

By digitally computing perfusion changes from ictal or postictal (peri-ictal) injections referenced to those acquired interictally, an enhanced method for localizing the epileptogenic area is reported. Computer-based image processing methods for quantifying regional percent change in the brain are applied to a group of 19 epilepsy patients after the injection of technetium-99m hexamethylpropylene amine oxime (HMPAO) and after acquiring single-photon emission tomography (SPET) data. Each patient's region of epileptogenesis was independently localized through pathology and/or successful surgery.

Reduced brain serotonin transporter availability in major depression as measured by [123I]-2 beta-carbomethoxy-3 beta-(4-iodophenyl)tropane and single photon emission computed tomography.

Background: Prior research has suggested reductions in the density of serotonin transporter (SERT) binding sites in blood platelets and post-mortem brain tissue of depressed patients. We sought to determine whether patients with unipolar major depression have diminished SERT availability as assessed by both brainstem [123I] beta-CIT SPECT and platelet [3H]paroxetine binding.

Methods: Drug-free depressed and healthy subjects were injected with 211 +/- 22 MBq [123I] beta-CIT and imaged 24 +/- 2 h later under equilibrium conditions.

Absence of an apolipoprotein E epsilon4 allele is associated with increased parietal regional cerebral blood flow asymmetry in Alzheimer disease.

Background: The apolipoprotein E (Apo E) epsilon4 allele has been associated with parietal metabolic abnormalities and asymmetries in asymptomatic subjects at risk for Alzheimer disease (AD). However, previous research has shown minimal effect of the epsilon4 allele on regional cerebral blood flow (rCBF) and metabolism in patients with probable AD.

Objective: To determine whether the Apo E epsilon4 allele is associated with parietal rCBF abnormalities and asymmetries in patients with probable AD.

Alterations of benzodiazepine receptors in type II alcoholic subjects measured with SPECT and [123I]iomazenil.

Objective: Alterations in cortical benzodiazepine receptor density have been described in postmortem and in vivo studies of alcoholic subjects. The authors attempted to replicate these findings using single photon emission computed tomography and the benzodiazepine receptor radiotracer [123I]iomazenil.

Method: They measured the distribution volume of benzodiazepine receptors in 11 recently detoxified patients with type II alcoholism and 11 healthy comparison subjects.

Significance of nonuniform attenuation correction in quantitative brain SPECT imaging.

Unlabelled: The purposes of this study were to develop a method for nonuniform attenuation correction of 123I emission brain images based on transmission imaging with a longer-lived isotope (i.e., 57Co) and to evaluate the relative improvement in quantitative SPECT images achieved with nonuniform attenuation correction.

Iodine-123-beta-CIT and iodine-123-FPCIT SPECT measurement of dopamine transporters in healthy subjects and Parkinson's patients.

Unlabelled: Iodine-123-beta-carbomethoxy-3 beta-(4-iodophenyltropane) (CIT) has been used as a probe of dopamine transporters in Parkinson's disease patients using SPECT. This tracer has a protracted period of striatal uptake enabling imaging 14-24 hr postinjection for stable quantitative measures of dopamine transporters, and it binds with nanomolar affinity to the serotonin transporter. Iodine-123 fluoropropyl (FP)CIT is an analog of [123I]-beta-CIT and has been shown to achieve peak tracer uptake in the brain within hours postinjection and to provide greater selectivity for the dopamine transporter.

[123I]beta-CIT SPECT imaging of dopamine transporter availability after mazindol administration in human cocaine addicts.

The in vivo potency of mazindol for binding to striatal dopamine transporters (DAT) was assessed by [123I]beta-CIT ([123I]2beta-carbomethoxy-3beta-(4-iodophenyl)tropane) single photon emission computed tomography (SPECT). Cocaine-dependent subjects (n = 12) underwent three SPECT scans; one before, between, and after subchronic (1 week) administration of 2 mg/day and 4 mg/day mazindol. For each scan, subjects were injected with [123I]beta-CIT and imaged 24 h later under equilibrium conditions.

Regional cerebral blood flow during acute and chronic abstinence from combined cocaine-alcohol abuse.

Regional cerebral blood flow (rCBF) was assessed using SPECT and HMPAO in ten cocaine abusers within 72 h of last cocaine use and then after 21 days of abstinence. In comparison to normals the cocaine abusers had significantly reduced rCBF in 11 of 14 brain regions with the largest reductions in the frontal and parietal cortex and greater rCBF in the brain stem. These perfusion defects appeared to be primarily due to combined alcohol and cocaine abuse and frontal but not parietal defects appeared to resolve partially during 21 days of abstinence.

Elevated striatal dopamine transporters during acute cocaine abstinence as measured by [123I] beta-CIT SPECT.

Objective: The authors examined whether striatal dopamine transporters were altered in acutely (96 hours or less) abstinent cocaine-abusing subjects, as suggested by postmortem studies.

Method: [123I] beta-CIT and single photon emission computed tomography were used to assess striatal dopamine transporter levels in 28 cocaine-abusing subjects and 24 comparison subjects matched as a group for age and gender.

Results: Results showed a significant (approximately 20%) elevation in striatal V3" values in acutely abstinent cocaine-abusing subjects relative to comparison subjects.

Increased striatal dopamine transmission in schizophrenia: confirmation in a second cohort.

Objective: The authors previously observed an increase in striatal dopamine transmission following amphetamine challenge in 15 untreated patients with schizophrenia compared to 15 matched healthy subjects. The purpose of this study was to replicate this finding in a new cohort of schizophrenic patients and healthy subjects.

Method: Fifteen patients with schizophrenia and 15 healthy subjects matched for age, gender, ethnicity, and parental socioeconomic status were recruited for this study.

Pulmonary embolus in pregnant patients: survey of ventilation-perfusion imaging policies and practices.

Purpose: To assess the policies and practices of nuclear medicine facilities as regards ventilation-perfusion (V-P) imaging in pregnant patients suspected of having pulmonary embolus.

Materials And Methods: Surveys were mailed to physician-directors of 1,000 randomly selected facilities at which nuclear imaging studies are performed. Information gathered included use of V-P imaging in pregnant patients, written policies, informed consent procedures, and modifications of standard protocols.

Plasma homovanillic acid and the dopamine transporter during cocaine withdrawal.

Background: Plasma homovanillic acid (HVA) has been used as a measure of central dopaminergic activity but the validity of this method continues to be investigated. We used single photon emission tomography (SPECT) assessment of the dopamine (DA) transporter for comparison with plasma HVA in subjects at varying stages of abstinence from cocaine.

Methods: Nineteen subjects were studied in two separate treatment sites.

Human biodistribution and dosimetry of iodine-123-fluoroalkyl analogs of beta-CIT.

Two new N-omega-fluoroalkyl analogs of [123I]2beta-carbomethoxy-3beta-(4-iodophenyl)tropane ([123I]beta-CIT), the fluoroethyl and fluoropropyl compounds ([123I]FE-CIT and [123I]FP-CIT, respectively), have been shown to have faster kinetics and better selectivity for the dopamine transporter than [123I]beta-CIT. We examined the organ biodistribution and radiation safety of these two compounds in six healthy volunteers who received an injection with each of the two compounds 2 weeks apart. Data were obtained on the Strichman 860 whole-body scanner.

Test/retest reproducibility of iodine-123-betaCIT SPECT brain measurement of dopamine transporters in Parkinson's patients.

Unlabelled: Iodine-123-beta-CIT has been used as a probe of dopamine transporters in Parkinson's disease patients using SPECT. We studied the test/retest reproducibility of SPECT measures in Parkinson's disease patients and healthy controls obtained after injection of [123I])beta-CIT in part to assess the utility of this tracer for longitudinal evaluation of striatal dopamine transporters as a marker of disease progression.

Methods: Seven Parkinson's disease patients and seven healthy control subjects participated in two [123I]beta-CIT SPECT scans separated by 7-21 days.

Imaging D2 receptor occupancy by endogenous dopamine in humans.

The impact of endogenous dopamine on in vivo measurement of D2 receptors in humans was evaluated with single photon emission computerized tomography (SPECT) by comparing the binding potential (BP) of the selective D2 radiotracer [123I]IBZM before and after acute dopamine depletion. Dopamine depletion was achieved by administration of the tyrosine hydroxylase inhibitor alpha-methyl-para-tyrosine (AMPT), given orally at a dose of 1 g every six hours for two days. AMPT increased [123I]IBZM BP by 28 +/- 16% (+/- SD, n = 9).

Single photon emission computerized tomography imaging of amphetamine-induced dopamine release in drug-free schizophrenic subjects.

The dopamine hypothesis of schizophrenia proposes that hyperactivity of dopaminergic transmission is associated with this illness, but direct observation of abnormalities of dopamine function in schizophrenia has remained elusive. We used a newly developed single photon emission computerized tomography method to measure amphetamine-induced dopamine release in the striatum of fifteen patients with schizophrenia and fifteen healthy controls. Amphetamine-induced dopamine release was estimated by the amphetamine-induced reduction in dopamine D2 receptor availability, measured as the binding potential of the specific D2 receptor radiotracer [123I] (S)-(-)-3-iodo-2-hydroxy-6-methoxy-N-[(1-ethyl-2-pyrrolidinyl) methyl]benzamide ([123I]IBZM).

Reproducibility of iodine-123-beta-CIT SPECT brain measurement of dopamine transporters.

Unlabelled: Iodine-123-beta-CIT has been used as a probe of monoamine transporters in human and nonhuman primates utilizing SPECT. To assess the utility of this tracer for measurement of striatal dopamine (DA) transporters in human disease, we studied the test/retest variability and reliability of SPECT measures obtained after bolus injection of [123I]beta-CIT 0-7 hr (Day 1) and 18-24 hr (Day 2) after administration.

Methods: For the Day 2 study, seven healthy humans (4 men, 3 women; aged 19-74 yr) participated in two [123I]beta-CIT SPECT scans separated by 7-14 days.

Human biodistribution and dosimetry of the SPECT D2 dopamine receptor radioligand [123I]IBF.

The research discussed in this article aimed to characterize better the biodistribution, excretion and radiation dosimetry of the single photon emission computed tomography (SPECT) D2 Dopamine receptor radioligand [123I]IBF. Following administration of 111 +/- 12 MBq [123I]IBF, seven healthy human subjects were scanned serially with a whole body imager over a 48-h period. Transmission images were obtained with a scanning line source for attenuation correction of the emission images.

[123I] beta-CIT/SPECT imaging demonstrates bilateral loss of dopamine transporters in hemi-Parkinson's disease.

We have used in vivo single-photon emission computed tomography (SPECT) of the dopamine transporter with 2 beta-carboxymethoxy-3 beta-(4-iodophenyl)tropane ([123I] beta-CIT) to investigate striatal dopamine transporter loss in patients with early Parkinson's disease (PD). Striatal uptake of ([123I] beta-CIT was compared in eight early-PD patients with exclusively hemi-parkinsonism and eight age- and sex-matched healthy subjects. [123I] beta-CIT striatal uptake was reduced by approximately 53% contralateral and by 38% ipsilateral to the clinically symptomatic side in the hemi-PD patients, compared with the mean striatal uptake in age- and sex-matched healthy subjects.

Continuous intravenous infusion of iodine-123-IBZM for SPECT determination of human brain dopamine receptor occupancy by antipsychotic agent RWJ-37796.

Unlabelled: PET has shown that dose-dependent in vivo occupancy of dopamine receptors by antipsychotic drugs is associated with clinical response to antipsychotic agents and the production of extrapyramidal side effects. We studied the feasibility of administering [123I]IBZM as a bolus plus continuous infusion over 8 hr to achieve unchanging regional brain activity levels, and the application of [123I]IBZM continuous infusion to examine the effects of the antipsychotic agent RWJ-37796, on striatal activity in humans.

Methods: Five healthy male subjects received a bolus of [123I]IBZM followed by a continuous infusion at a bolus (mCi):infusion (mCi/hr) ratio of 6:1.

Euphorigenic doses of cocaine reduce [123I]beta-CIT SPECT measures of dopamine transporter availability in human cocaine addicts.

The in vivo potency of euphorigenic doses of intravenous cocaine for displacing [123I]beta-CIT ([123I]2 beta-carbomethoxy-3 beta-(4-iodophenyl)tropane) binding to striatal dopamine transporters (DAT) was assessed in human cocaine addicts using single photon emission computed tomography (SPECT). Cocaine-dependent subjects (n = 6) were injected with [123I]beta-CIT and imaged 24 h later under equilibrium conditions. Sequential cocaine infusions (0.

Decreased single-photon emission computed tomographic [123I]beta-CIT striatal uptake correlates with symptom severity in Parkinson's disease.

Previous studies have utilized single-photon emission computed tomography (SPECT) to demonstrate decreased [123I]beta-CIT striatal uptake in idiopathic Parkinson disease (PD) patients. The present study extends this work by examining SPECT outcome measures in a larger group of PD patients with varying disease severity. Twenty-eight L-dopa-responsive PD patients (Hoehn-Yahr stages 1-4) and 27 healthy controls had SPECT scans at 18 to 24 hours after injection of [123I]beta-CIT.

[123I]beta-CIT SPECT imaging of striatal dopamine transporter binding in Tourette's disorder.

Objective: The authors examined whether subjects with Tourette's disorder have greater than normal striatal dopamine transporter densities, as suggested by previous post-mortem findings.

Method: Single photon emission computed tomography (SPECT) and [123I]2 beta-carbomethoxy-3 beta-(4-iodophenyl)tropane ([123I]beta-CIT) were used to assess dopamine transporter levels in five adult patients with Tourette's disorder and five age- and gender-matched healthy comparison subjects.

Results: Striatal [123I]beta-CIT binding was a mean of 37% (range = 6%-79%) higher in the subjects with Tourette's disorder than in the comparison subjects, and each Tourette's disorder patient had a higher level than his or her paired comparison subject.