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R Van Heertum

Publications and source records attributed to R Van Heertum.

18 recordsLinked to original sources
PubMed2002

rCBF/SPECT in the evaluation of inner-city minority patients with a history of impaired memory: a pilot blind read pre- and poststudy.

Eight patients (seven women), mean +/- SD T1 age 68.57 +/- 12.43 years, average educational level 5.83 +/- 3.70 years, had two Tc-99m ECD SPECT examinations separated by an average 8.49 +/- 5.59 months. Patients were imaged using standard Harlem Hospital acquisition and processing protocols with approximately 30 mCi of ECD on a Prism 3000 triple head gamma camera. Images were interpreted by an independent reader blinded to the patients' clinical history and imaging date. T1 psychiatric diagnosis was seven Alzheimer's dementia (AD) and one depression. Eight T1 images were interpreted as abnormal, six indicative of AD. Binomial 95% two-tail confidence interval for T1 agreement between diagnosis and interpretation was 0.25 0.63 0.92. T2 diagnosis was seven AD and one none. Seven T2 images were abnormal and indicative of AD, and one was normal. T2 confidence interval was 0.34 0.75 0.97. These findings suggest SPECT's value in assessing AD in uneducated socioeconomically disadvantaged geriatric patients.

Aged↗
PubMed2001

Dopamine D(2) receptor availability and amphetamine-induced dopamine release in unipolar depression.

BACKGROUND: Reduced dopaminergic transmission has been implicated in the pathophysiology of major depression. The aim of the present study was to measure striatal D(2) receptor availability and amphetamine-induced dopamine release in nonpsychotic, unmedicated, unipolar patients during an episode of major depression. METHODS: The striatal equilibrium specific to nonspecific partition coefficient (V(3)") of the D(2) receptor antagonist [(123)I]IBZM was measured with single photon emission computerized tomography before and after amphetamine administration in 9 depressed subjects and 10 matched healthy control subjects. RESULTS: No significant differences were observed in preamphetamine D(2) receptor availability between depressed patients (0.73 +/- 0.08) and control subjects (0.78 +/- 0.10, p =.23). Amphetamine-induced reduction in [(123)I]IBZM V(3)" (DeltaV(3)") was similar in depressed patients (-9.8 +/- 5.5%) and control subjects (-7.8 +/- 2.5%, p =.32). Amphetamine induced a transient improvement in symptomatology in depressed patients, but this improvement did not correlate with [(123)I]IBZM DeltaV(3)". CONCLUSIONS: This study did not replicate previously reported alterations in striatal D(2) receptor density in depressed patients and suggests that stimulant-induced dopamine release is not altered in major depression.

Adolescent↗
PubMed2001

SPECT perfusion imaging in the diagnosis of Alzheimer's disease: a clinical-pathologic study.

OBJECTIVE: Numerous studies have suggested that temporoparietal hypoperfusion seen on brain imaging with SPECT may be useful in diagnosing AD during life. However, these studies have often been limited by lack of pathologic validation and unrepresentative samples. The authors performed this study to determine whether SPECT imaging provides diagnostically useful information in addition to that obtained from a clinical examination. METHODS: Clinical data and SPECT images were collected prospectively, and patients were followed to autopsy. Clinical history, pathologic findings, and SPECT images were each evaluated by raters blind to other features, and clinical and SPECT diagnoses were compared with pathologic diagnoses. The study population consisted of 70 patients with dementia, followed to autopsy; 14 controls followed to autopsy; and 71 controls (no autopsy performed). The primary outcome was the likelihood of a pathologic diagnosis of AD given a positive clinical diagnosis, a positive SPECT diagnosis, and both. RESULTS: When all participants (patients and controls) were included in the analysis, the clinical diagnosis of "probable" AD was associated with an 84% likelihood of pathologic AD. A positive SPECT scan raised the likelihood of AD to 92%, whereas a negative SPECT scan lowered the likelihood to 70%. SPECT was more useful when the clinical diagnosis was "possible" AD, with the likelihood of 67% without SPECT, 84% with a positive SPECT, and 52% with a negative SPECT. Similar results were found when only patients with dementia were included in the analysis. CONCLUSIONS: In the evaluation of dementia, SPECT imaging can provide clinically useful information indicating the presence of AD in addition to the information that is obtained from clinical evaluation.

Aged↗
PubMed2001

Differential occupancy of somatodendritic and postsynaptic 5HT(1A) receptors by pindolol: a dose-occupancy study with [11C]WAY 100635 and positron emission tomography in humans.

Augmentation of selective serotonin reuptake inhibitors (SSRIs) therapy by the 5-HT(1A) receptor agent pindolol may reduce the delay between initiation of antidepressant treatment and clinical response. This hypothesis is based on the ability of pindolol to block 5-HT(1A) autoreceptors in the dorsal raphe nuclei (DRN) and to potentiate the increase in 5-HT transmission induced by SSRIs. However, placebo-controlled clinical studies of pindolol augmentation of antidepressant therapy have reported inconsistent results. Here, we evaluated the occupancy of 5-HT(1A) receptors during treatment with pindolol controlled release (CR) in nine healthy volunteers with Positron Emission Tomography and [11C]WAY 100635. Subjects were studied four times: at baseline, following one week of pindolol CR 7.5 mg/day (4 and 10 hrs post dose), and following one dose of pindolol CR 30 mg(4 hrs post dose). Occupancy of the DRN was 40 +/- 29% on scan 2, 38 +/- 26% on scan 3, and 64 +/- 15% on scan 4. The average occupancy in all other regions was significantly lower at each doses (18 +/- 5% on scan 2, 12 +/- 3% on scan 3, and 42 +/- 4% on scan 4). These results suggest that the blockade in the DRN reached in clinical studies (7.5 mg/day) might be too low and variable to consistently augment the therapeutic effect of SSRIs. However, these data indicate that pindolol exhibits in vivo selectivity for the DRN 5-HT(1A) autoreceptors. As DRN selectivity is desirable for potentiation of 5-HT function, this observation represents an important proof of concept for the development of 5-HT(1A) agents in this application.

Adult↗
PubMed2001

Imaging human mesolimbic dopamine transmission with positron emission tomography: I. Accuracy and precision of D(2) receptor parameter measurements in ventral striatum.

Dopamine transmission in the ventral striatum (VST), a structure which includes the nucleus accumbens, ventral caudate, and ventral putamen, plays a critical role in the pathophysiology of psychotic states and in the reinforcing effects of virtually all drugs of abuse. The aim of this study was to assess the accuracy and precision of measurements of D(2) receptor availability in the VST obtained with positron emission tomography on the high-resolution ECAT EXACT HR+ scanner (Siemens Medical Systems, Knoxville, TN, U.S.A.). A method was developed for identification of the boundaries of the VST on coregistered high-resolution magnetic resonance imaging scans. Specific-to-nonspecific partition coefficient (V(3)") and binding potential (BP) of [(11)C]raclopride were measured twice in 10 subjects, using the bolus plus constant infusion method. [(11)C]Raclopride V(3)" in the VST (1.86 +/- 0.29) was significantly lower than in the dorsal caudate (DCA, 2.33 +/- 0.28) and dorsal putamen (DPU, 2.99 +/- 0.26), an observation consistent with postmortem studies. The reproducibility of V(3)" and BP were appropriate and similar in VST (V(3)" test-retest variability of 8.2% +/- 6.2%, intraclass correlation coefficient = 0.83), DCA (7.7% +/- 5.1%, 0.77), DPU (6.0% +/- 4.1%, 0.71), and striatum as a whole (6.3% +/- 4.1%, 0.78). Partial volume effects analysis revealed that activities in the VST were significantly contaminated by counts spilling over from the adjacent DCA and DPU: 70% +/- 5% of the specific binding measured in the VST originated from D(2) receptors located in the VST, whereas 12% +/- 3% and 18% +/- 3% were contributed by D(2) receptors in the DCA and DPU, respectively. Thus, accuracy of D(2) receptor measurement is improved by correction for partial voluming effects. The demonstration of an appropriate accuracy and precision of D(2) receptor measurement with [(11)C]raclopride in the VST is the first critical step toward the use of this ligand in the study of synaptic dopamine transmission at D(2) receptors in the VST using endogenous competition techniques.

Adult↗
PubMed2000

Different brain networks mediate task performance in normal aging and AD: defining compensation.

OBJECTIVE: To determine whether the pathologic mechanisms of AD alter the brain networks subserving performance of a verbal recognition task. BACKGROUND: Functional imaging studies comparing task-related activation in AD patients and controls generally have not used network analysis and have not controlled for task difficulty. METHODS: H2 15O PET was used to measure regional cerebral blood flow in 14 patients and 11 healthy elders during the performance of a serial verbal recognition task under two conditions: low demand, with study list size (SLS) equal to one; and titrated demand, with SLS adjusted so that each subject recognized words at 75% accuracy. The Scaled Subprofile Model was used to identify networks of regionally covarying activity across these task conditions. RESULTS: In the elders, higher SLS was associated with the recruitment of a network of brain areas involving left anterior cingulate and anterior insula (R2 = 0.94; p < 0.0001). Three patients also expressed this network. In the remaining patients, higher SLS was associated with the recruitment of an alternate network consisting of left posterior temporal cortex, calcarine cortex, posterior cingulate, and the vermis (R2 = 0.81, p < 0.001). Expression of this network was unrelated to SLS in the elders and more intact AD patients. CONCLUSIONS: The patients' use of the alternate network may indicate compensation for processing deficits. The transition from the normal to the alternate network may indicate a point where brain disease has irreversibly altered brain function and thus may have important implications for therapeutic intervention.

Aged↗
PubMed2000

Positron emission tomography study of pindolol occupancy of 5-HT(1A) receptors in humans: preliminary analyses.

Preclinical studies in rodents suggest that augmentation of serotonin reuptake inhibitors (SSRIs) therapy by the 5-hydroxytryptamine(1A) (5-HT(1A)) receptor agent pindolol might reduce the delay between initiation of treatment and antidepressant response. This hypothesis is based on the ability of pindolol to potentiate the increase in serotonin (5-HT) transmission induced by SSRIs, an effect achieved by blockade of the 5-HT(1A) autoreceptors in the dorsal raphe nuclei (DRN). However, placebo-controlled clinical studies of pindolol augmentation of antidepressant therapy have reported inconsistent results. Here, we evaluated the occupancy of 5-HT(1A) receptors following treatment with controlled release pindolol in nine healthy volunteers with positron-emission tomography (PET). Each subject was studied four times: at baseline (scan 1), following 1 week of oral administration of pindolol CR (7.5 mg/day) at peak level, 4 h after the dose (scan 2), and at 10 h following the dose (scan 3), and following one dose of pindolol CR (30 mg) (at peak level, 4 h) (scan 4). Pindolol occupancy of 5-HT(1A) receptors was evaluated in the DRN and cortical regions as the decrease in binding potential (BP) of the radiolabelled selective 5-HT(1A) antagonist [carbonyl-(11)C]WAY-100635 or [carbonyl-(11)C] N-(2-(4-(2-methoxyphenyl)-1-piperazinyl)ethyl)-N-(2-pyridyl)cyclohexa necarboxamide abbreviated as [(11)C]WAY-100635. Pindolol dose-dependently decreased [(11)C]WAY-100635 BP. Combining all the regions, occupancy was 20 +/- 8% at scan 2, 14 +/- 8% at scan 3, and 44 +/- 8% at scan 4. The results of this study suggest that at doses used in clinical studies of augmentation of the SSRI effect by pindolol (2.5 mg t.i.d.), the occupancy of 5-HT(1A) receptors is moderate and highly variable between subjects. This factor might explain the variable results obtained in clinical studies. On the other hand, at each dose tested, pindolol occupancy of 5-HT(1A) receptors was higher in the DRN compared to cortical regions, demonstrating a significant in vivo selectivity for DRN 5-HT(1A) autoreceptors relative to cortico-limbic postsynaptic receptors. This selectivity is necessary for the potentiation of 5-HT transmission, and this finding represents an important proof of concept in the development of 5-HT(1A) agents for this application. Early evaluation of new drugs with PET imaging will enable rapid screening of compounds based on DRN selectivity and more appropriate determination of doses for clinical trials.

Adult↗
PubMed2000

Measurement of striatal and extrastriatal dopamine D1 receptor binding potential with [11C]NNC 112 in humans: validation and reproducibility.

To evaluate the postulated role of extrastriatal D1 receptors in human cognition and psychopathology requires an accurate and reliable method for quantification of these receptors in the living human brain. [11C]NNC 112 is a promising novel radiotracer for positron emission tomography imaging of the D1 receptor. The goal of this study was to develop and evaluate methods to derive D1 receptor parameters in striatal and extrastriatal regions of the human brain with [11C]NNC 112. Six healthy volunteers were studied twice. Two methods of analysis (kinetic and graphical) were applied to 12 regions (neocortical, limbic, and subcortical regions) to derive four outcome measures: total distribution volume, distribution volume ratio, binding potential (BP), and specific-to-nonspecific equilibrium partition coefficient (k3/k4). Both kinetic and graphic analyses provided BP and k3/k4 values in good agreement with the known distribution of D1 receptors (striatum > limbic regions = neocortical regions > thalamus). The identifiability of outcome measures derived by kinetic analysis was excellent. Time-stability analysis indicated that 90 minutes of data collection generated stable outcome measures. Derivation of BP and k3/k4 by kinetic analysis was highly reliable, with intraclass correlation coefficients (ICCs) of 0.90+/-0.06 (mean +/- SD of 12 regions) and 0.84+/-0.11, respectively. The reliability of these parameters derived by graphical analysis was lower, with ICCs of 0.72+/-0.17 and 0.58+/-0.21, respectively. Noise analysis revealed a noise-dependent bias in the graphical but not the kinetic analysis. In conclusion, kinetic analysis of [11C]NNC 112 uptake provides an appropriate method with which to derive D1 receptor parameters in regions with both high (striatal) and low (extrastriatal) D1 receptor density.

Adult↗
PubMed2000

Validation and reproducibility of measurement of 5-HT1A receptor parameters with [carbonyl-11C]WAY-100635 in humans: comparison of arterial and reference tisssue input functions.

Serotonin 5-HT(1A) receptors are implicated in the pathophysiology of neuropsychiatric conditions. The goal of this study was to evaluate methods to derive 5-HT(1A) receptor parameters in the human brain with positron emission tomography (PET) and [carbonyl-(11)C]WAY 100635. Five healthy volunteer subjects were studied twice. Three methods of analysis were used to derive the binding potential (BP), and the specific to nonspecific equilibrium partition coefficient (k3/k4). Two methods, kinetic analysis based on a three compartment model and graphical analysis, used the arterial plasma time-activity curves as the input function to derive BP and k3/k4. A third method, the simplified reference tissue model (SRTM), derived the input function from uptake data of a region of reference, the cerebellum, and provided only k3/k4. All methods provided estimates of regional 5-HT(1A) receptor parameters that were highly correlated. Results were consistent with the known distribution of 5-HT(1A) receptors in the human brain. Compared with kinetic BP, graphical analysis slightly underestimated BP, and this phenomenon was mostly apparent in small size-high noise regions. Compared with kinetic k3/k4, the reference tissue method underestimated k3/k4 and the underestimation was apparent primarily in regions with high receptor density. Derivation of BP by both kinetic and graphical analysis was highly reliable, with an intraclass correlation coefficient (ICC) of 0.84 +/- 0.14 (mean +/- SD of 15 regions) and 0.84 +/- 0.19, respectively. In contrast, the reliability of k3/k4 was lower, with ICC of 0.53 +/- 0.28, 0.47 +/- 0.28, and 0.55 +/- 0.29 for kinetic, graphical, and reference tissue methods, respectively. In conclusion, derivation of BP by kinetic analysis using the arterial plasma input function appeared as the method of choice because of its higher test-retest reproducibility, lower vulnerability to experimental noise, and absence of bias.

Adult↗
PubMed2000

Schizophrenia subgroups differing in dichotic listening laterality also differ in neurometabolism and symptomatology.

Schizophrenia patients vary in right ear advantage (REA) on dichotic listening tests for assessing left hemispheric dominance for language processing. The authors examined if patients with low REA differed from other patients in symptoms and in resting brain metabolism. SPECT was conducted during visual fixation for 9 healthy control subjects and 16 schizophrenia patients: 8 with normal and 8 with diminished REA. REA-diminished patients had greater positive symptoms and lower mental status scores (all P<0.05) and had right middle temporal gyrus hypermetabolism. Both schizophrenia groups had decreased right frontal and increased medial temporal lobe metabolism vs. control subjects. REA-diminished patients had right temporal lobe hypermetabolism under a resting condition (eyes open, visual fixation). Results suggest reduced right ear (left hemisphere) advantage for dichotic word perception in schizophrenia is related to a predisposition to overactivate right temporal lobe regions and to positive symptoms. In contrast, the prefrontal-medial temporal imbalance present in both patient groups may typify the schizophrenia syndrome.

Adult↗
PubMed1999

SPECT study of visual fixation in schizophrenia and comparison subjects.

BACKGROUND: The consistent association of impaired eye movements and schizophrenia suggests a relationship between the neurobiology of the illness and visual pursuit systems. Visual fixation (VF), an eye "movement" task at zero velocity, is the simplest such abnormality in schizophrenia patients and their relatives. METHODS: We used a VF task for a functional imaging study. Six neuroleptic-free schizophrenia patients and eight gender and mean age matched comparison subjects had SPECT scans with 20 mCi of Tc99-HMPAO, during VF on a simple blue line intersection. MEDX data saved in ANALYZE format for SPM 95 was used to generate paired t-test statistical data for display in Talairach space, with rCBF changes given as Z-scores. RESULTS: Patients, compared to controls, had increased rCBF in both the parahippocampal gyrus (bilaterally) and in the right fusiform gyrus. They had decreased rCBF in the left frontal cortex, including medial and superior frontal gyri and anterior cingulate. Overall, compared to controls, patients had medial temporal lobe hyperperfusion along with left prefrontal hypoperfusion. CONCLUSIONS: These findings are consistent with the hypothesized imbalance between the medial temporal and frontal lobes that is postulated for schizophrenia. It was of interest that the relative rCBF differences between schizophrenia patients and controls in this small sample were observable with this cognitively non-demanding visual fixation task.

Adult↗
PubMed1999

PET studies of binding competition between endogenous dopamine and the D1 radiotracer [11C]NNC 756.

NNC 756 ((+)-8-chloro-5-(2,3-dihydrobenzofuran-7-yl)-7-hydroxy-3-methyl-2,3,4,5- tetrahydro-1H-3-benzazepine) is a new high affinity dopamine (DA) D1 receptor antagonist. Labeled with C-11, it has been used as a PET radiotracer to visualize D1 receptors both in striatal and extrastriatal areas, such as the prefrontal cortex. The goal of this study was to evaluate several methods for derivation of D1 receptor binding potential (BP) with [11C]NNC 756 in baboons, and to use these methods to assess the vulnerability of [11C]NNC 756 binding to competition by endogenous DA. A three-compartment model provided a good fit to PET data acquired following a single bolus injection. BP values obtained with this analysis were in good agreement with values derived from in vitro studies. BP values measured following injection of the potent DA releaser amphetamine (1 mg/kg, n=2) were similar to values measured under control conditions. Kinetic parameters derived from single bolus experiments were used to design a bolus plus continuous infusion administration protocol aimed at achieving a state of sustained binding equilibrium. Injection of amphetamine during sustained equilibrium did not affect [11C]NNC 756 binding. Similar results were observed with another D1 radiotracer, [11C]SCH 23390. Doses of amphetamine used in this study are known to reduce by 20-40% the binding potential of several D2 receptors radiotracers. Therefore, the absence of displacement of [11C]NNC 756 by an endogenous DA surge may indicate important differences between D1 and D2 receptors in vivo, such as differences in proportion of high affinity states not occupied by DA at baseline. These findings may also imply that a simple binding competition model is inadequate to account for the effects of manipulation of endogenous DA levels on the in vivo binding of radiolabeled antagonists.

Amphetamine↗
PubMed1997

Functional brain imaging and neuropsychological testing in Lyme disease.

Differentiating neuropsychiatric Lyme disease from a primary psychiatric disorder can be a daunting task. This article describes how functional brain imaging and neuropsychological testing can be particularly valuable in helping to make diagnostic distinctions. In addition to a review of the relevance of functional imaging to neuropsychiatry in general, recent findings are presented regarding the use of single photon emission computed tomographic (SPECT) imaging in Lyme disease.

Brain↗
PubMed1995

Adaptive changes of autoregulation in chronic cerebral hypotension with arteriovenous malformations: an acetazolamide-enhanced single-photon emission CT study.

PURPOSE: To evaluate the relationship among feeding arterial pressure, lesion size, and perfusion in cerebral cortex adjacent to cerebral arteriovenous malformations (AVMs). METHODS: Eleven patients with hemispheric AVMs underwent 99mTc hexamethyl-propyleneamine oxime single-photon emission CT before and after 1 g of acetazolamide was administered intravenously. AVM volume was estimated from MR dimensions and measured according to the method described by Pasqualin. Pressure measurements were obtained in arteries feeding the cortex adjacent to AVMs. Single-photon emission CT regions of interest were defined in cortex adjacent to the AVM and compared with contralateral regions using the Mountz method to estimate a baseline and dynamic (acetazolamide-challenged) perfusion defect volume. RESULTS: Eight of 11 patients had baseline perfusion defects, but these defects were unrelated to feeding artery pressures (y = -.06x + 9.92, r2 = .04) or the dynamic change in defect volume after acetazolamide administration (y = .01x + .02, r2 = .002). However, there was a correlation between AVM volume and the baseline defect volume (y = .75x - 1.9, r2 = .76). Five patients had increased defect volume after acetazolamide administration; 5 patients had either no change in or improvement of perfusion. Dynamic changes in defect volume were related to feeding artery pressures. CONCLUSION: Perilesional baseline perfusion defects appear to be related to lesion size and not to local arterial pressure. Cerebrovascular reserve generally was preserved, and perfusion defects appeared to be more pronounced with lower arterial pressures in feeding vessels. Although vasodilatory testing can unmask hemodynamic failure with severe local hypotension, baseline perfusion defects near the lesion and distant perfusion changes are more likely attributable to other causes such as mass-related or neurogenic changes.

Acetazolamide↗
PubMed1994

A multi-institutional study of interobserver agreement in the evaluation of dementia with rCBF/SPET technetium-99m exametazime (HMPAO).

Although specific patterns of technetium-99m exametazime [99mTc-hexamethylpropylene amine oxime (HMPAO)] brain single-photon emission tomography (SPET) uptake have been described for patients with dementia, no multi-institutional study has evaluated interobserver agreement. Interobserver agreement for 99mTc-HMPAO brain SPET uptake patterns in 50 clinically diagnosed demented subjects from four institutions were studied. Neurologists classified these subjects as presumed Alzheimer's disease (n = 21), confirmed Alzheimer's disease (n = 10), multi-infarct dementia (n = 9), HIV-related dementia (n = 7), or "mixed" (n = 3). In addition 20 normal (five per institution) 99mTc-HMPAO studies were included in a randomized blinded evaluation by three readers each from a different institution. Readers classified the general appearance of the images in one of four categories: normal, globally decreased uptake, focal areas of decreased uptake, and patchy changes in uptake. Consensus results show a sensitivity of 72% and specificity of 79% for identifying abnormalities in scans of demented subjects. Readers also rated 99mTc-HMPAO uptake in eight designated regions in each hemisphere. Significant reader agreement (P < 0.01) for the classification by general appearance and the ratings of regional uptake was obtained. This study demonstrates that interpretation of regional cerebral blood flow/SPET images is concordant across multiple institutions and readers.

AIDS Dementia Complex↗
PubMed1984

The problem of liver metastasis.

The detection and management of tumors metastatic to the liver is still unsettled. The uniformly poor prognosis only underlines the need to diagnose and treat the primary malignant lesion earlier, before systemic metastases lodge in the liver, lung or brain. Serologic markers are not specific or sensitive enough although when used serially they may follow the course of some tumors. The exciting advances in radiologic diagnosis have allowed a more accurate and pictorial representation of disease, exciting cross-sectional views but not earlier diagnosis. The use of scans and ultrasound as a screening measure is investigational only as there is not good evidence to support this as a routine screening test. The treatment of hepatic metastases is also insoluble. For primary lesions that are controlled surgically and whose natural history is measured in years (not months) a more aggressive approach is justified. Lesions confined to one lobe, particularly single lesions, lend themselves to resection. Segmental or wedge resection is the equal of formal hepatic lobectomy and is safer for patients and surgeons. For most patients (70 to 85 percent) operation is not a reasonable choice. How does one select from no therapy, intravenous chemotherapy, intraarterial chemotherapy (implantable pumps, infusion plus embolization) or hepatic artery embolization? These decisions are not easily reached. Institutional enthusiasm is as much a reflection of local expertise and biases as are meaningful data. There are responders to all of these methods, but few long-term survivors. Side effects that limit life style and activity detract from some of the remaining days. Today patients share in the decision-making process. Their own biases are frequently in discord with the treating physician's. When this exists and data do not support one treatment method we acquiesce to the patient's wishes and use his or her experience to increase our data base. Intraarterial chemotherapy is making a strong impact, objective information not withstanding. Unless an implantable pump is covered by third party payments we prefer a "test trial" of several monthly intraarterial injections of chemotherapy to see if a positive effect occurs. Intravenous chemotherapy remains our therapeutic choice particularly if part of a trial. If there is no response and side effects are severe, we prefer to withdraw treatment.

Angiography↗
PubMedDate not supplied

PET in clinical practice.

Positron emission tomography (PET) is a nuclear medicine imaging tool that has expanded from its vital role in basic research into clinical medicine. This noninvasive diagnostic modality is used in cardiac perfusion and viability; in neurologic conditions such as epilepsy, dementia, and tumor; and in a wide range of common cancers to diagnose, stage, and monitor therapy. The importance of PET in clinical practice is growing rapidly, and the number of PET centers across the country is increasing. It is imperative, therefore, that physicians are familiar with PET, and know where this tool can be the most useful and cost-effective modality for patient management.

Cost-Benefit Analysis↗