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Biomedical subjects

Andrew Newberg

Publications and source records attributed to Andrew Newberg.

12 recordsLinked to original sources
PubMed2007

Dopamine transporter density may be associated with the depressed affect in healthy subjects.

OBJECTIVES: Increased levels of dopamine transporter (DAT) binding have been reported in patients with major depression. We used the selective DAT radiopharmaceutical Tc-TRODAT-1 and SPECT brain imaging, to examine differences in DAT levels in healthy subjects with and without depressive affect. METHODS: We compared striatal DAT binding affinity in 73 healthy subjects to their scores on the depressive symptoms subscale of the Profile of Mood States (POMS). Regions of interest in the basal ganglia of the brain were examined. Distribution volume ratios (DVRs) of Tc-TRODAT-1 binding affinity were calculated from the SPECT scan data, and comparisons among subjects with low and high depressive symptom ratings were calculated using unpaired t-tests and the Pearson correlation. RESULTS: We observed a greater Tc-TRODAT-1 DVR in the right caudate of subjects with high POMS mood scores compared to subjects with low scores on depressive items on the POMS (2.99+/-0.35 and 2.79+/-0.35, respectively; P=0.009). There was also a weak, but significant correlation between higher Tc-TRODAT-1 DVRs in the right caudate and depressive symptoms scores (r=0.23, P=0.05). CONCLUSIONS: These data suggest that Tc-TRODAT-1 binding affinity to DAT sites may be associated with depressive affect in healthy subjects. The finding also supports prior observations of greater Tc-TRODAT-1 DVRs in patients with major depressive episode.

Adult↗
PubMed2006

Artificial neural network classifier for the diagnosis of Parkinson's disease using [99mTc]TRODAT-1 and SPECT.

Imaging the dopaminergic neurotransmitter system with positron emission tomography (PET) or single photon emission tomography (SPECT) is a powerful tool for the diagnosis of Parkinson's disease (PD). Previous studies have indicated that human observers have a diagnostic accuracy similar to conventional ROI analysis of SPECT imaging data. Consequently, it has been hypothesized that an artificial neural network (ANN), which can mimic the pattern recognition skills of human observers, may provide similar results. A set of patients with PD, and normal healthy control subjects, were studied using the dopamine transporter tracer [(99m)Tc]TRODAT-1 and SPECT. The sample was comprised of 81 patients (mean age +/- SD: 63.4 +/- 10.4 years; age range: 39.0-84.2 years) and 94 healthy controls (mean age +/- SD: 61.8 +/- 11.0 years; age range: 40.9-83.3 years). The images were processed to extract the striatum and the striatal pixel values were used as inputs to a three-layer ANN. The same set of data was used to both train and test the ANN, in a 'leave one out' procedure. The diagnostic accuracy of the ANN was higher than any previous analysis method applied to the same data (94.4% total accuracy, 97.5% specificity and 91.4% sensitivity). However, it should be stressed that, as with all applications of an ANN, it was difficult to interpret precisely what triggers in the images were being detected by the network.

Adult↗
PubMed2006

Comparison of region-of-interest analysis and human observers in the diagnosis of Parkinson's disease using [99mTc]TRODAT-1 and SPECT.

This study determined the relative accuracy of diagnosis of Parkinson's disease (PD) using SPECT imaging data, comparing a semi-quantitative region-of-interest (ROI) approach and human observers. A set of patients with PD and normal healthy control subjects were studied using the dopamine transporter tracer [(99m)Tc]TRODAT-1 and SPECT. The sample comprised 81 patients (mean age +/- SD, 63.4 +/- 10.4 years; age range, 39.0-84.2 years) and 94 healthy controls (mean age +/- SD, 61.8 +/- 11.0 years; age range, 40.9-83.3 years). A standardized template containing six ROIs was transposed onto subregions of the brain, and the ratio of striatal to background ROI values was used as a semi-quantitative outcome measure. All images were used in a human observer study, with four experienced investigators. The data from the observer and ROI studies were analysed using a receiver operating characteristic (ROC) analysis, where the area under the ROC curve (AUC) indicated the diagnostic accuracy. ROI analysis and human observers gave similar diagnostic performance (mean observer AUC = 0.89, best ROI AUC = 0.90). This suggested that the human observers are visually acquiring similar information from the images that are contained in the semi-quantitative striatal uptake.

Adult↗
PubMed2005

Neuroimaging in traumatic brain imaging.

Traumatic brain injury (TBI) is a common and potentially devastating clinical problem. Because prompt proper management of TBI sequelae can significantly alter the clinical course especially within 48 h of the injury, neuroimaging techniques have become an important part of the diagnostic work up of such patients. In the acute setting, these imaging studies can determine the presence and extent of injury and guide surgical planning and minimally invasive interventions. Neuroimaging also can be important in the chronic therapy of TBI, identifying chronic sequelae, determining prognosis, and guiding rehabilitation.

Animals↗
PubMed2004

Clinical validation of fully 3-D versus 2.5-D RAMLA reconstruction on the Philips-ADAC CPET PET scanner.

INTRODUCTION: Fully three-dimensional (3-D) reconstruction algorithms have the potential to better utilize PET data acquired in true 3-D acquisition modes, as compared to 2-D approaches involving data reduction through rebinning procedures followed by a 2-D or 2.5-D reconstruction. Our previous studies, involving simulated and real phantom data from PET scanners working purely in 3-D acquisition mode, showed that the fully 3-D reconstruction approaches bring appreciable improvement on physical measures and visual image quality as well. Reconstruction procedures utilized in those studies were based upon the row action maximum likelihood algorithm (RAMLA) implemented on our clinical scanners. The purpose of this study was to investigate if the fully 3-D RAMLA reconstruction software brings an appreciable improvement in clinical image quality and reader confidence. MATERIALS AND METHODS: Ninety patient scans acquired on the Philips CPET scanner at our institution were reconstructed using 2.5-D RAMLA and 3-D RAMLA with differing reconstruction parameters. These scans were blindly presented to four experienced PET scan readers who graded various aspects of image quality. RESULTS: Our study concluded that 3-D RAMLA on the CPET scanner reduces artifacts and image noise and improves clinical confidence in interpreting PET images. CONCLUSION: This study led to the routine use of 3-D RAMLA reconstruction on the CPET scanner at our institution.

Algorithms↗
PubMed2003

A metabolic imaging severity rating scale for the assessment of cognitive impairment.

PURPOSE: This study was designed to validate a simple scoring system for evaluating fluorodeoxyglucose (FDG) positron emission tomographic (PET) scans that can be used routinely in patients undergoing the clinical assessment of cognitive impairment. METHODS: The FDG-PET scans of 106 patients with cognitive impairment (65 with Alzheimer disease, 16 with frontal lobe dementia, and 25 atypical cases) were acquired using the PENN-PET scanner 40 minutes after the intravenous administration of 8 mCi FDG. Metabolic activity in various anatomic structures of the brain was scored using the following qualitative scale: 4 = normal; 3 = mildly decreased; 2 = moderately decreased; 1 = severely decreased; and 0 = no activity. Regions of interest were also placed over these regions to obtain a quantitative value. Two distinct scores were obtained. Values for visual and sensorimotor cortices, thalami, basal ganglia, and cerebellum comprised score I. Score II consisted of the values for the frontal, temporal, and parietal cortices. The qualitative metabolic imaging severity rating scale (MISRS) was compared with a quantitative MISRS (obtained from the region-of-interest analysis of the same structures). The MISRS was then compared with the results from the Mini-Mental Status Examination (MMSE) and the Dementia Severity Rating Score (DSRS). RESULTS: In all patients, the qualitative MISRS scores correlated significantly with the quantitative MISRS (r = 0.73, P < 0.0001). In all patients with cognitive impairment, the qualitative and quantitative MISRS scores correlated significantly with the DSRS and the MMSE (P < 0.001). In patients with Alzheimer disease, the qualitative and quantitative MISRS significantly correlated with the DSRS and MMSE. CONCLUSION: A simple and practical rating scale can be used to assess the severity of cognitive impairment in patients with different types of dementing illnesses.

Brain↗
PubMed2003

Greater availability of brain dopamine transporters in major depression shown by [99m Tc]TRODAT-1 SPECT imaging.

OBJECTIVE: Studies of laboratory animals have shown that administration of antidepressants of all pharmacological classes produces changes in dopamine transporter binding affinity. These observations suggest that dopamine transporter function may play a critical role in the pathophysiology of depression. The present study was an examination of the availability of brain dopamine transporter sites in patients with major depression and in healthy comparison subjects. METHOD: Single photon emission computed tomographic (SPECT) brain scans were acquired for 15 drug-free depressed patients and 46 age- and gender-matched healthy comparison subjects by using [(99m)Tc]TRODAT-1, a selective dopamine transporter imaging agent. Specific regions of interest in the basal ganglia and supratentorial areas of the brain were examined. Specific uptake values of dopamine transporter [(99m)Tc]TRODAT-1 binding affinity were calculated from the SPECT scan data, and the values for the patients and healthy subjects were compared. RESULTS: The specific uptake values of [(99m)Tc]TRODAT-1 binding were significantly higher in the right anterior putamen (23%), right posterior putamen (36%), left posterior putamen (18%), and left caudate nucleus (12%) of the patients than in the comparison subjects. These differences persisted when the data were further analyzed according to gender and age. CONCLUSIONS: Dopamine transporter affinity may be higher than normal in the basal ganglia of depressed patients. These findings suggest that dopamine function may be altered in depression and may also be a mechanism of antidepressant activity.

Adult↗
PubMed2003

Cerebral blood flow during meditative prayer: preliminary findings and methodological issues.

Meditative practices typically require several coordinated cognitive activities. This study measured changes in cerebral blood flow during "verbal" based meditation by Franciscan nuns involving the internal repetition of a particular phrase. These results are compared with those we previously described in eight Buddhist meditators who use a type of "visualization" technique. Three experienced practitioners of verbal meditation were injected via i.v. at rest with 260 MBq of Tc-99m HMPAO and scanned 30 min. later on a triple head SPECT camera for 45 min. Following the baseline scan, subjects meditated for approximately 40 min. at which time they were injected with 925 MBq of HMPAO while they continued to meditate for 10 min. more (total of 50 min. of meditation). The injection during meditation was designed not to disturb practice. Subjects were scanned 20 min. later for 30 min. Counts were obtained for regions of interest for major brain structures and normalized to whole-brain blood flow. Compared to baseline, mean verbal meditation scans showed increased blood flow in the prefrontal cortex (7.1%), inferior parietal lobes (6.8%), and inferior frontal lobes (9.0%). There was a strong inverse correlation between the blood flow, change in the prefrontal cortex and in the ipsilateral superior parietal lobe (p<.01). This study on a limited number of subjects demonstrated the feasibility of studying different types of meditation with neuroimaging techniques, suggested that several coordinated cognitive processes occur during meditation, and also raised important methodological issues.

Adult↗
PubMed2002

Determination of regional cerebral function with FDG-PET imaging in neuropsychiatric disorders.

Functional brain imaging using 18F fluorodeoxyglucose (FDG) and positron emission tomography (PET) has greatly enhanced our understanding of brain function both in normal conditions as well as in a wide variety of neuropsychiatric disorders. We review the uses of FDG PET in the diagnosis, management, and follow-up of patients with neuropsychiatric disorders. This article will also explore what FDG-PET imaging has revealed in these neuropsychiatric disorders and how these findings relate to both research and clinical applications.

Blood Glucose↗
PubMedDate not supplied

Pilot study on the effect of estrogen replacement therapy on brain dopamine transporter availability in healthy, postmenopausal women.

OBJECTIVE: Authors investigated the association between estrogen replacement therapy (ERT) and dopamine transporter (DAT) availability in women. METHODS: Thirteen postmenopausal women were administered ERT and underwent neuroimaging, using single-photon emission computed tomography (SPECT) and [99mTc]TRODAT-1, a radioligand that binds DAT. In this 6-week pilot study, subjects underwent SPECT before ERT, after 4 weeks of 0.625 mg/day of conjugated estrogens (CEE), and after an additional 2 weeks of 0.625 mg/day CEE plus 10 mg/day of medroxyprogesterone acetate. Specific uptake values (SUVs) of [99mTc]TRODAT-1 were calculated for the caudate and putamen. RESULTS: When compared with baseline values, [99mTc]TRODAT-1 binding demonstrated a modest, but statistically significant, increase in the left anterior putamen after 4 weeks of CEE. After the 6-week ERT intervention, both the left and right anterior putamen demonstrated an increase in SUVs. CONCLUSION: Short-term administration of ERT in postmenopausal women is associated with a modest increase in DAT in the putamen. These findings may further the understanding of how ERT is associated with improvement in Parkinson's disease and late-onset schizophrenia.

Aged↗