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J R Moeller

Publications and source records attributed to J R Moeller.

At least 19 recordsLinked to original sources
PubMed1995

Regional cerebral blood flow in mood disorders: IV. Comparison of mania and depression.

Cortical regional cerebral blood flow (rCBF) was assessed in minimally medicated, relatively young adults in episodes of either acute mania (n = 11) or major depression (n = 11) and in matched normal control subjects (n = 11), using the 133xenon inhalation method, under eyes-closed, resting conditions. The three groups were equivalent in global CBF. Both patient groups showed significant reductions of rCBF in anterior cortical areas and reduction of the normal anteroposterior gradient. In addition, there was evidence of abnormal, albeit similar, patterns of flow lateralization on a regional basis in both clinical groups compared with normal subjects. An exploratory analysis revealed preliminary evidence of rCBF differences between the clinical groups, localized to the inferior frontal cortex. Otherwise, the evidence in this study suggests that young adult manic and depressed patients are predominantly similar in cortical rCBF parameters.

Administration, Inhalation↗
PubMed1995

The reliability of quantitative electroencephalography as an indicator of cerebral ischemia.

The electroencephalogram (EEG) has been used to detect episodes of cerebral ischemia during various surgical procedures. Recently, computerized systems for recording and interpreting the quantitative EEG (QEEG) have been used by anesthesiologists because of their ease of application, clarity of display, and reported ability to identify ischemic EEG changes. However, the extent to which automated techniques of QEEG interpretation reliably differentiate cerebral ischemia from the confounding effects of anesthetics and other sources of "artifact" is not completely established. In this study, EEGs were recorded before and after defibrillator testing in patients undergoing implantable cardioverter defibrillator (ICD) placement and during analogous time periods in control patients undergoing abdominal surgery. EEGs were subjected to standard visual inspection by an experienced electroencephalographer and QEEG analysis with a commercially available system was used for automated EEG interpretation in order to evaluate the reliability of this quantitative technique. The CIMON technique identified episodes which met previously defined criteria for QEEG cerebral dysfunction and ischemic pattern in both groups, despite the presumed absence of cerebral ischemia in the control patients. Since there was no evidence of cerebral ischemia in the raw EEGs of either the ICD patients or the controls, these QEEG changes were not confirmed by conventional techniques of EEG interpretation. Our results suggest that caution is warranted when using automated systems for intraoperative interpretation of EEG.

Adult↗
PubMed1995

Early differential diagnosis of Parkinson's disease with 18F-fluorodeoxyglucose and positron emission tomography.

Early-stage Parkinson's disease (EPD) is often clinically asymmetric. We used 18F-fluorodeoxyglucose (FDG) and PET to assess whether EPD can be detected by a characteristic pattern of regional metabolic asymmetry. To identify this pattern, we studied 10 EPD (Hoehn and Yahr stage I) patients (mean age 61.1 +/- 11.1 years) using 18F-FDG and PET to calculate regional metabolic rates for glucose. The scaled subprofile model (SSM) was applied to metabolic asymmetry measurements for the combined group of EPD patients and normal subjects to identify a specific covariation pattern that discriminated EPD patients from normal subjects. To determine whether this pattern could be used diagnostically, we studied a subsequent group of five presumptive EPD patients (mean age 50.9 +/- 18.3), five normal subjects (mean age 44.6 +/- 15.3), and nine patients with atypical drug-resistant early-stage parkinsonism (APD) (mean age 44.6 +/- 14.0). In each member of this prospective cohort, we calculated the expression of the EPD-related covariation pattern (subject scores) on a case-by-case basis. We also studied 11 of the EPD patients, five patients with APD, and 10 normal subjects with 18F-fluorodopa (FDOPA) and PET to measure presynaptic nigrostriatal dopaminergic function, and we assessed the accuracy of differential diagnosis with both PET methods using discrimination analysis. SSM analysis disclosed a significant topographic contrast profile characterized by covariate basal ganglia and thalamic asymmetries. Subject scores for this profile accurately discriminated EPD patients from normal subjects and APD patients (p < 0.0001). Group assignments into the normal or parkinsonian categories with FDG/PET were comparable to those achieved with FDOPA/PET, although APD and EPD patients were not differentiable by the latter method. Metabolic brain imaging with FDG/PET may be useful in the differential diagnosis of EPD.

Adult↗
PubMed1995

Assessment of disease severity in parkinsonism with fluorine-18-fluorodeoxyglucose and PET.

UNLABELLED: Fluorine-18-fluorodeoxyglucose (FDG) and PET have been used to identify an abnormal regional metabolic covariance pattern in Parkinson's disease (PD). To examine the potential use of this covariance pattern as a metabolic imaging marker for PD, we describe the Topographic Profile Rating (TPR), which is a method for calculating subject scores for this pattern in individual PD patients. We then assess the relationship between these metabolic measures and objective independent disease severity ratings. METHODS: Two independent groups of PD patients were studied with FDG-PET. Group A consisted of 23 patients (mean age 60.2 +/- 12.2; mean Hoehn and Yahr stages 2.4 +/- 1.3) and Group B had 14 patients (mean age 49.0 +/- 12.1; mean Hoehn and Yahr stage 3.2 +/- 1.2). The regional cerebral metabolic rates for glucose (rCMRGlc) in all patients in each group were measured. TPR was used to calculate subject scores for the disease-related covariance pattern on a patient-by-patient basis. RESULTS: In both PD patient groups, subject scores correlated with Hoehn and Yahr disease severity ratings (Group A: r = 0.59, p < 0.004; Group B: 0.57, p < 0.04), quantitative ratings for bradykinesia (Group A: r = 0.63, p < 0.002; Group B: r = 0.61, p < 0.03), rigidity (Group A: r = 0.59, p < 0.004; Group B: r = 0.59, p < 0.04), but not with tremor. CONCLUSION: These findings indicate that regional metabolic covariance patterns are robust imaging markers of disease severity. FDG-PET may be useful clinically in assessing parkinsonian disability and disease progression.

Adult↗
PubMed1994

Regional cerebral blood flow in mood disorders, III. Treatment and clinical response.

BACKGROUND: Global and regional deficits in cerebral blood flow and glucose metabolism have been reported in major depression, but there is limited information on the effects of somatic treatment and clinical recovery on these abnormalities. METHODS: We assessed cortical blood flow with the xenon 133 technique in depressed patients prior to a course of electroconvulsive therapy (ECT), 30 minutes before and 50 minutes after a single treatment, and during the week following ECT. Acute (preictal and postictal) effects of a single treatment also were studied in manic patients. RESULTS: In the depressed and manic groups, larger blood flow reductions in the acute period, both globally and in particular patterns of brain regions, were associated with a superior clinical outcome following the treatment course. In depressed patients, similar patterns were observed for the blood flow changes over a full treatment course. Blood flow reductions in anterior cortical regions were strongly associated with a positive clinical response in both depression and mania. CONCLUSIONS: The findings indicated that cerebral blood flow abnormalities in major depression were not reversed by successful treatment with ECT. Rather, particularly in responders, ECT resulted in additional perfusion reductions. The therapeutic properties of ECT are related to reduced functional brain activity in specific neural regions.

Adult↗
PubMed1994

The metabolic topography of parkinsonism.

We used [18F]fluorodeoxyglucose/positron emission tomography (18F-FDG/PET) and a statistical model of regional covariation to study brain topographic organization in parkinsonism. We studied 22 patients with Parkinson's disease (PD), 20 age-matched normal volunteers, and 10 age- and severity-matched patients with presumed striatonigral degeneration (SND). We used FDG/PET to calculate global, regional, and normalized metabolic rates for glucose (GMR, rCMRglc, rCMRglc/GMR). Metabolic parameters in the three groups were compared using an analysis of variance, with a correction for multiple comparisons, and discriminant analysis. The scaled subprofile model (SSM) was applied to the combined rCMRglc dataset to identify topographic covariance profiles that distinguish PD patients from SND patients and normals. GMR, rCMRglc, and rCMRglc/GMR were normal in PD; caudate and lentiform rCMRglc/GMR was reduced in the SND group (p < 0.01). SSM analysis of the combined group of patients and normals revealed a significant topographic profile characterized by increased metabolic activity in the lentiform nucleus and thalamus associated with decreased activity in the lateral frontal, paracentral, inferior parietal, and parietooccipital areas. Individual subject scores for this profile were significantly elevated in PD patients compared with normals and SND patients (p < 0.001) and discriminated the three groups. In the PD group, subject scores for this factor correlated with individual subject Hoehn and Yahr (H & Y) scores (p < 0.02), and with quantitative rigidity (p < 0.01) and bradykinesia (p < 0.03) ratings, but not with tremor ratings. SSM analysis of right-left metabolic asymmetries yielded a topographic contrast profile that accurately discriminated mildly affected PD patients (H & Y Stage I) from normals. Our findings demonstrate that abnormal topographic covariance profiles exist in parkinsonism. These profiles have potential clinical application as neuroimaging markers in parkinsonism.

Adult↗
PubMed1994

Physical properties and quantification of the ECT stimulus: I. Basic principles.

The physical properties of the electroconvulsive therapy (ECT) stimulus markedly affect both efficacy and side effects. We review basic principles in characterizing these physical properties and in quantifying the ECT stimulus. The topics discussed include the application of Ohm's law, alternative composite units of ECT dosage (energy and charge), the use of constant-current, constant-voltage, and constant-energy principles in ECT devices, the nature of current shunting in ECT and the determinants of impedance, the relations between impedance and seizure threshold, the seizure-eliciting efficiency of alternative stimulus waveforms and of stimulus parameter configurations, and the role of reactive components (capacitance and inductance) in the ECT circuit. New findings are also presented regarding several of these issues.

Electric Impedance↗
PubMed1991

Abnormal cerebral glucose metabolism in long-term survivors of childhood acute lymphocytic leukemia.

Chemotherapy and radiation treatment of the central nervous system may cause delayed neurotoxicity in children with acute lymphocytic leukemia. We evaluated 12 long-term survivors of childhood leukemia using [18F]fluorodeoxyglucose positron emission tomography, computed tomography scans, clinical neurological examinations, and neuropsychological tests. Regional cerebral metabolic rate for glucose (rCMRGlc) values for white matter were lower in the older long-term survivors (greater than 18 years old) treated with cranial radiation and intrathecal chemotherapy than in normal control subjects or survivors who had been treated with intrathecal chemotherapy alone. The ratio of white matter: cortex rCMRGlc values was lower than control values in the long-term survivors treated with cranial radiation and intrathecal chemotherapy, regardless of age, but not in those treated with intrathecal chemotherapy alone. By contrast, thalamic rCMRGlc values were lower than control values in older survivors regardless of treatment, and the ratio for thalamus:cortex rCMRGlc values was lower in all the treatment groups than in the control subjects. The highest rCMRGlc values were found in the youngest children, indicating an important effect of age on cerebral glucose metabolism. No neuropsychological deficits were identified in patients treated only with intrathecal chemotherapy; however, lower IQ scores were found in the long-term survivors who had been treated with cranial radiation and intrathecal chemotherapy. Treatment of the central nervous system with cranial radiation and intrathecal chemotherapy may cause prolonged alterations in white-matter and thalamic rCMRGlc, which may permit the identification and assessment of neurotoxicity in long-term survivors of acute lymphocytic leukemia by [18F]fluorodeoxyglucose positron emission tomography.

Adolescent↗
PubMed1991

Absolute quantitation in neurological PET: do we need it?

This article addresses the question posed in the title by examining the effects of parameters traditionally associated with improved absolute quantitation, on the analysis of 12 acquired immune deficiency syndrome dementia complex (ADC) patients compared to a normal control group. Results are discussed within the framework of the subprofile scaling model (SSM) for analyzing patterns of regional covariation. It is demonstrated that the ability to extract measures of group discrimination and disease progression are unaffected by (1) limited improvements in image resolution, (2) the use of transmission scan smoothing, (3) the application of a scatter deconvolution correction, and (4) converting region-of-interest measurements of counts per voxel to measurements of regional CMRglc. This "robustness" of the SSM approach is partly due to the extraction of disease-related subject weights, independent of any subject's global scaling effects. It is argued that other analysis techniques that initially reduce intersubject variation (e.g., using regional ratios or normalizing by global metabolic rates before applying traditional multivariate procedures) lack analytic features that may be important to identify multidimensional, disease-related image patterns. Based on the ADC patient data, it is concluded that measures of group discrimination and disease progression will not necessarily benefit from the organization of parameters traditionally associated with improved absolute quantitation.

AIDS Dementia Complex↗
PubMed1991

Effects of percent thresholding on the extraction of [18F]fluorodeoxyglucose positron emission tomographic region-of-interest data.

Although we and others have employed a thresholding strategy to extract "peak" values from positron emission tomographic (PET) regions of interest (ROIs), the effects of peak picking on fitted fluorodeoxyglucose rate constants, regional metabolic rate for glucose (rCMRglc) profiles, patterns of regional metabolic covariation, and PET-neurobehavioral correlations have not been systematically investigated. Our results suggest that under some commonly encountered imaging conditions percent thresholding may increase sensitivity to regional activation; however, the effect of thresholding is determined by a number of factors, including the relative magnitude of regional activation, ROI size, and the specific threshold selected. The difference-annulus concept is proposed as a means to study the effects of different region drawing and thresholding strategies, and to determine if a given ROI contains one and only one source of covarying metabolic activity.

AIDS Dementia Complex↗
PubMed1991

A regional covariance approach to the analysis of functional patterns in positron emission tomographic data.

This article provides a complete description of the subprofile scaling model (SSM) approach to the analysis of positron emission tomography (PET) data. The goals and assumptions underlying the development of SSM are outlined, and its strengths and weaknesses are discussed. It is demonstrated that all obtainable information about regional ratios can, in theory, be derived from the SSM regional covariance patterns. A general constraint on the ability to effectively remove global variation while identifying region-specific information about PET data sets is outlined and discussed within the SSM framework. Finally, an extension of the SSM technique to the generation of disease-specific covariance patterns is demonstrated for paraneoplastic cerebellar degeneration, the acquired immune deficiency syndrome dementia complex, and Parkinson's disease, and the importance of multidimensional descriptions of disease, such as may be obtained from PET data using SSM, is emphasized.

AIDS Dementia Complex↗
PubMed1991

The metabolic landscape of cortico-basal ganglionic degeneration: regional asymmetries studied with positron emission tomography.

Regional metabolic rate for glucose (rCMRGlc) was estimated using [18F]fluorodeoxyglucose (FDG) and positron emission tomography (PET) in five patients (four men, one woman; mean age 68; mean disease duration 2.4 years) with clinical findings consistent with the syndrome of cortico-basal ganglionic degeneration (CBGD). Left-right rCMRGlc asymmetry, (L-R)/(L + R) x 100, was calculated for 13 grey matter regions and compared with regional metabolic data from 18 normal volunteers and nine patients with asymmetrical Parkinson's disease (PD). In the CBGD group mean metabolic asymmetry values in the thalamus, inferior parietal lobule and hippocampus were greater than those measured in normal control subjects and patients with asymmetrical PD (p less than 0.02). Parietal lobe asymmetry of 5% or more was evident in all CBGD patients, whereas in PD patients and normal controls, all regional asymmetry measures were less than 5% in absolute value. Measures of frontal, parietal and hemispheric metabolic asymmetry were found to be positively correlated with asymmetries in thalamic rCMRGlc (p less than 0.05). The presence of cortico-thalamic metabolic asymmetry is consistent with the focal neuropathological changes reported in CBGD brains. Our findings suggest that metabolic asymmetries detected with FDG/PET may support a diagnosis of CBGD in life.

Aged↗
PubMed1990

Regional cerebral blood flow in mood disorders. I. Comparison of major depressives and normal controls at rest.

We measured regional cerebral blood flow with the xenon 133 inhalation technique in 41 patients with major depressive disorder and 40 matched, normal controls during an eyes-closed, resting condition. The depressed group had a marked reduction in global cortical blood flow. To examine topographic abnormalities, traditional multivariate analyses were applied, as well as a new scaled subprofile model developed to identify abnormal functional neural networks in clinical samples. Both approaches indicated that the depressed sample had an abnormality in topographic distribution of blood flow, in addition to the global deficit. The scaled subprofile model identified the topographic abnormality as being due to flow reduction in the depressed patients in selective frontal, central, superior temporal, and anterior parietal regions. This pattern may reflect dysfunction in the parallel distributed cortical network involving frontal and temporoparietal polymodal association areas. The extent of this topographic abnormality, as revealed by the scaled subprofile model, was associated with both patient age and severity of depressive symptoms.

Adult↗
PubMed1990

The metabolic anatomy of Parkinson's disease: complementary [18F]fluorodeoxyglucose and [18F]fluorodopa positron emission tomographic studies.

We studied the metabolic anatomy of typical Parkinson's disease (PD) using [18F]fluorodeoxyglucose (FDG) and [18F]fluorodopa (FDOPA) and positron emission tomography (PET). Fourteen PD patients (mean age 49 years) had FDG/PET scans, of which 11 were scanned with both FDOPA and FDG. After the injection of FDOPA, brain uptake and arterial plasma radioactivity were monitored for 2 h. Striatal FDOPA uptake was analyzed with regard to a two-compartment model, and target-to-background ratios (TBRs) and TBR-versus-time slopes were also calculated. Regional patterns of metabolic covariation were extracted from FDG/PET data using the Scaled Subprofile Model (SSM). SSM pattern weights, FDOPA uptake constants (Ki), TBRs, and TBR slopes were correlated with clinical measures for bradykinesia, rigidity, tremor, gait disturbance, left-right asymmetry, dementia, and overall disease severity. In PD patients, rate constants for FDOPA uptake correlated with individual measures of bradykinesia (p = 0.001) and gait disability (p less than 0.05). SSM analysis revealed a distinct pattern of regional metabolic asymmetries, which correlated with motor asymmetries (p less than 0.001) and left-right differences in Ki (p less than 0.01). Our data suggest that in PD patients, FDG/PET and FDOPA/PET may provide unique and complementary information about underlying disease processes.

Adult↗
PubMed1989

The time course of steroid action on blood-to-brain and blood-to-tumor transport of 82Rb: a positron emission tomographic study.

Blood-to-brain and blood-to-tumor transport rate constants for Rb (K1) and apparent tissue blood volume (Vb) were estimated in 8 patients with primary or metastatic brain tumors before and approximately 6 hours after a 100-mg intravenous bolus injection of dexamethasone using 82Rb and positron emission tomography. Eight additional patients were studied to evaluate test-retest variability and repositioning errors. Six hours following dexamethasone administration tumor K1 (but not Vb) was significantly reduced compared with contralateral control brain regions (p less than 0.03). These data are consistent with our previously published 24-hour-postdexamethasone data and suggest that comparable effects of corticosteroids on brain/tumor capillaries may be observed at 5 to 6 and 24 hours. The time course of dexamethasone-induced alterations in brain/tumor capillary permeability supports the view that these alterations may be responsible for at least some of the antiedema effects of corticosteroids.

Adolescent↗
PubMed1989

Positron emission tomographic measurement of blood-to-brain and blood-to-tumour transport of 82Rb. I: Error analysis and computer simulations.

Unidirectional blood-to-brain and blood-to-tumour transport rate constants (K1) for 82Rb (half-life 76 s) and plasma water volume per unit mass of brain/tumour tissue (Vp) can be estimated in vivo using dynamic positron emission tomography (PET). The accuracy of these estimates depends upon the accuracy of PET measurements of regional brain/tumour radioactivity and scintillation well detector measurements of whole-blood radioactivity, which, in turn, depend upon the time course of arterial blood radioactivity. A two-compartmental model has been employed to derive estimates for K1, k2 (efflux rate constant) and Vp from 82Rb/PET data. Errors in these parameter estimates have been studied (1) qualitatively using sensitivity function analysis and (2) quantitatively using computer simulations. The effect of adding a third irreversible compartment and its unidirectional rate constant, k3, has also been investigated. The advantages and disadvantages of bolus injection vs continuous infusion protocols are discussed. Precision in estimated parameters from actual patient data is compared to that obtained from computer simulations in part II of this paper.

Blood↗
PubMed1989

Positron emission tomographic measurement of blood-to-brain and blood-to-tumour transport of 82Rb. II: Clinical data and validation of technique.

Computer simulations and error analysis of a simple two-compartment, passive-diffusion exchange model for 82Rb across the blood-brain-barrier (BBB) have demonstrated the feasibility of obtaining useful estimates of unidirectional rate constant (K1) and tissue-blood water volume (Vb) in vivo using dynamic positron tomography (PET). The coefficients of variation (CV) in parameter estimates for 20 studies on ten patients are shown to have mean values of 10% for tumour K1 and Vb, 6% for normal brain Vb and 30% for normal brain K1. Ten test-retest studies show a very high correlation (R2 greater than 0.88) between the estimated parameter values. Apparent tissue blood volume (Vb) estimates obtained from 82Rb studies underestimate the blood volumes obtained by single-breath C15O studies by approximately 15%. In normal brain the extraction of rubidium (E) is small (less than 10%), and gives rise to a linear relationship between K1 and permeability-surface area product (PS). In tumour, however, E is larger (greater than 30%), and results in a non-linear relationship between these values. For both tumour and normal brain, K1 was found to be independent of regional cerebral blood flow (rCBF). The data from these clinical studies are in agreement with the predictions of the computer simulations and suggest the suitability of 82Rb/PET in the quantification of BBB functional changes.

Adolescent↗