Deep learning-based multimodality classification of chronic mild traumatic brain injury using resting-state functional MRI and PET imaging

Mild traumatic brain injury (mTBI) is a public health concern. The present study aimed to develop an automatic classifier to distinguish between patients with chronic mTBI (n = 83) and healthy controls (HCs) (n = 40). Resting-state functional MRI (rs-fMRI) and positron emission tomography (PET) imaging were acquired from the subjects. We proposed a novel deep-learning-based framework, including an autoencoder (AE), to extract high-level latent and rectified linear unit (ReLU) and sigmoid activation functions. Single and multimodality algorithms integrating multiple rs-fMRI metrics and PET data were developed. We hypothesized that combining different imaging modalities provides complementary information and improves classification performance. Additionally, a novel data interpretation approach was utilized to identify top-performing features learned by the AEs. Our method delivered a classification accuracy within the range of 79-91.67% for single neuroimaging modalities. However, the performance of classification improved to 95.83%, thereby employing the multimodality model. The models have identified several brain regions located in the default mode network, sensorimotor network, visual cortex, cerebellum, and limbic system as the most discriminative features. We suggest that this approach could be extended to the objective biomarkers predicting mTBI in clinical settings.

Treatment effects of N-acetyl cysteine on resting-state functional MRI and cognitive performance in patients with chronic mild traumatic brain injury: a longitudinal study

Mild traumatic brain injury (mTBI) is a significant public health concern, specially characterized by a complex pattern of abnormal neural activity and functional connectivity. It is often associated with a broad spectrum of short-term and long-term cognitive and behavioral symptoms including memory dysfunction, headache, and balance difficulties. Furthermore, there is evidence that oxidative stress significantly contributes to these symptoms and neurophysiological changes. The purpose of this study was to assess the effect of N-acetylcysteine (NAC) on brain function and chronic symptoms in mTBI patients. Fifty patients diagnosed with chronic mTBI participated in this study. They were categorized into two groups including controls (CN, n = 25), and patients receiving treatment with N-acetyl cysteine (NAC, n = 25). NAC group received 50 mg/kg intravenous (IV) medication once a day per week. In the rest of the week, they took one 500 mg NAC tablet twice per day. Each patient underwent rs-fMRI scanning at two timepoints including the baseline and 3 months later at follow-up, while the NAC group received a combination of oral and IV NAC over that time. Three rs-fMRI metrics were measured including fractional amplitude of low frequency fluctuations (fALFF), degree centrality (DC), and functional connectivity strength (FCS). Neuropsychological tests were also assessed at the same day of scanning for each patient. The alteration of rs-fMRI metrics and cognitive scores were measured over 3 months treatment with NAC. Then, the correlation analysis was executed to estimate the association of rs-fMRI measurements and cognitive performance over 3 months (p < 0.05). Two significant group-by-time effects demonstrated the changes of rs-fMRI metrics particularly in the regions located in the default mode network (DMN), sensorimotor network, and emotional circuits that were significantly correlated with cognitive function recovery over 3 months treatment with NAC (p < 0.05). NAC appears to modulate neural activity and functional connectivity in specific brain networks, and these changes could account for clinical improvement. This study confirmed the short-term therapeutic efficacy of NAC in chronic mTBI patients that may contribute to understanding of neurophysiological effects of NAC in mTBI. These findings encourage further research on long-term neurobehavioral assessment of NAC assisting development of therapeutic plans in mTBI.

Machine learning-based classification of chronic traumatic brain injury using hybrid diffusion imaging

Background and purpose

Traumatic brain injury (TBI) can cause progressive neuropathology that leads to chronic impairments, creating a need for biomarkers to detect and monitor this condition to improve outcomes. This study aimed to analyze the ability of data-driven analysis of diffusion tensor imaging (DTI) and neurite orientation dispersion imaging (NODDI) to develop biomarkers to infer symptom severity and determine whether they outperform conventional T1-weighted imaging.

Materials and methods

A machine learning-based model was developed using a dataset of hybrid diffusion imaging of patients with chronic traumatic brain injury. We first extracted the useful features from the hybrid diffusion imaging (HYDI) data and then used supervised learning algorithms to classify the outcome of TBI. We developed three models based on DTI, NODDI, and T1-weighted imaging, and we compared the accuracy results across different models.

Results

Compared with the conventional T1-weighted imaging-based classification with an accuracy of 51.7-56.8%, our machine learning-based models achieved significantly better results with DTI-based models at 58.7-73.0% accuracy and NODDI with an accuracy of 64.0-72.3%.

Conclusion

The machine learning-based feature selection and classification algorithm based on hybrid diffusion features significantly outperform conventional T1-weighted imaging. The results suggest that advanced algorithms can be developed for inferring symptoms of chronic brain injury using feature selection and diffusion-weighted imaging.

Identification of chronic mild traumatic brain injury using resting state functional MRI and machine learning techniques

Mild traumatic brain injury (mTBI) is a major public health concern that can result in a broad spectrum of short-term and long-term symptoms. Recently, machine learning (ML) algorithms have been used in neuroscience research for diagnostics and prognostic assessment of brain disorders. The present study aimed to develop an automatic classifier to distinguish patients suffering from chronic mTBI from healthy controls (HCs) utilizing multilevel metrics of resting-state functional magnetic resonance imaging (rs-fMRI). Sixty mTBI patients and forty HCs were enrolled and allocated to training and testing datasets with a ratio of 80:20. Several rs-fMRI metrics including fractional amplitude of low-frequency fluctuation (fALFF), regional homogeneity (ReHo), degree centrality (DC), voxel-mirrored homotopic connectivity (VMHC), functional connectivity strength (FCS), and seed-based FC were generated from two main analytical categories: local measures and network measures. Statistical two-sample t-test was employed comparing between mTBI and HCs groups. Then, for each rs-fMRI metric the features were selected extracting the mean values from the clusters showing significant differences. Finally, the support vector machine (SVM) models based on separate and multilevel metrics were built and the performance of the classifiers were assessed using five-fold cross-validation and via the area under the receiver operating characteristic curve (AUC). Feature importance was estimated using Shapley additive explanation (SHAP) values. Among local measures, the range of AUC was 86.67-100% and the optimal SVM model was obtained based on combined multilevel rs-fMRI metrics and DC as a separate model with AUC of 100%. Among network measures, the range of AUC was 80.42-93.33% and the optimal SVM model was obtained based on the combined multilevel seed-based FC metrics. The SHAP analysis revealed the DC value in the left postcentral and seed-based FC value between the motor ventral network and right superior temporal as the most important local and network features with the greatest contribution to the classification models. Our findings demonstrated that different rs-fMRI metrics can provide complementary information for classifying patients suffering from chronic mTBI. Moreover, we showed that ML approach is a promising tool for detecting patients with mTBI and might serve as potential imaging biomarker to identify patients at individual level.

Clinical trial registration

[clinicaltrials.gov], identifier [NCT03241732].

Cerebral Blood Flow and Brain Functional Connectivity Changes in Older Adults Participating in a Mindfulness-Based Stress Reduction Program

There is a growing interest in the potential beneficial effects of mindfulness meditation training in protecting against age-related physical, emotional, and cognitive decline. The current prospective, single-center, single-arm study investigated if functional magnetic resonance imaging-based changes in cerebral blood flow and brain functional connectivity could be observed in 11 elderly adults (mean age 79) after participation in a Mindfulness-Based Stress Reduction (MBSR) program. The results showed significantly (p < 0.05) altered cerebral blood flow and functional connectivity in the cingulate gyrus, limbic structures, and subregions of the temporal and frontal lobes, similar to findings of other meditation-related studies in younger populations. Furthermore, these changes were also associated with significant improvements in depression symptoms. This study suggests that the MBSR program can potentially modify cerebral blood flow and connectivity in this population.

Resting-State Functional MRI Metrics in Patients With Chronic Mild Traumatic Brain Injury and Their Association With Clinical Cognitive Performance

Mild traumatic brain injury (mTBI) accounts for more than 80% of people experiencing brain injuries. Symptoms of mTBI include short-term and long-term adverse clinical outcomes. In this study, resting-state functional magnetic resonance imaging (rs-fMRI) was conducted to measure voxel-based indices including fractional amplitude of low-frequency fluctuation (fALFF), regional homogeneity (ReHo), and functional connectivity (FC) in patients suffering from chronic mTBI; 64 patients with chronic mTBI at least 3 months post injury and 40 healthy controls underwent rs-fMRI scanning. Partial correlation analysis controlling for age and gender was performed within mTBI cohort to explore the association between rs-fMRI metrics and neuropsychological scores. Compared with controls, chronic mTBI patients showed increased fALFF in the left middle occipital cortex (MOC), right middle temporal cortex (MTC), and right angular gyrus (AG), and increased ReHo in the left MOC and left posterior cingulate cortex (PCC). Enhanced FC was observed from left MOC to right precuneus; from right MTC to right superior temporal cortex (STC), right supramarginal, and left inferior parietal cortex (IPC); and from the seed located at right AG to left precuneus, left superior medial frontal cortex (SMFC), left MTC, left superior temporal cortex (STC), and left MOC. Furthermore, the correlation analysis revealed a significant correlation between neuropsychological scores and fALFF, ReHo, and seed-based FC measured from the regions with significant group differences. Our results demonstrated that alterations of low-frequency oscillations in chronic mTBI could be representative of disruption in emotional circuits, cognitive performance, and recovery in this cohort.

N-acetyl cysteine administration affects cerebral blood flow as measured by arterial spin labeling MRI in patients with multiple sclerosis

BACKGROUND

The purpose of this study was to explore if administration of N-acetyl-cysteine (NAC) in patients with multiple sclerosis (MS) resulted in altered cerebral blood flow (CBF) based on Arterial Spin Labeling (ASL) magnetic resonance imaging (MRI).

METHODS

Twenty-three patients with mild to moderate MS, (17 relapsing remitting and 6 primary progressive) were randomized to either NAC plus standard of care (N = 11), or standard of care only (N = 12). The experimental group received NAC intravenously (50 mg/kg) once per week and orally (500mg 2x/day) the other six days. Patients in both groups were evaluated initially and after 2 months (of receiving the NAC or waitlist control) with ASL MRI to measure CBF. Clinical symptom questionnaires were also completed at both time points.

RESULTS

The CBF data showed significant differences in several brain regions including the pons, midbrain, left temporal and frontal lobe, left thalamus, right middle frontal lobe and right temporal/hippocampus (p < 0.001) in the MS group after treatment with NAC, when compared to the control group. Self-reported scores related to cognition and attention were also significantly improved in the NAC group as compared to the control group.

CONCLUSIONS

The results of this study suggest that NAC administration alters resting CBF in MS patients, and this is associated with qualitative improvements in cognition and attention. Given these findings, large scale efficacy studies will be of value to determine the potential clinical impact of NAC over the course of illness in patients with MS, as well as the most effective dosages and differential effects across subpopulations.

N-acetyl Cysteine Administration Is Associated With Increased Cerebral Glucose Metabolism in Patients With Multiple Sclerosis: An Exploratory Study

Background: Multiple Sclerosis (MS) is an autoimmune disease marked by progressive neurocognitive injury. Treatment options affording neuroprotective effects remain largely experimental. The purpose of this proof of concept study was to explore the effects of N-acetyl-cysteine (NAC) on cerebral glucose metabolism (CMRGlu) and symptoms in patients with multiple sclerosis (MS).

Methods: Twenty-four patients with MS were randomized to either NAC plus standard of care, or standard of care only (waitlist control). The experimental group received NAC intravenously once per week and orally the other 6 days. Patients in both groups were evaluated at baseline and after 2 months (of receiving the NAC or waitlist control period) with an integrated Position Emission Tomography (PET)/ Magnetic Resonance Imaging (MRI) scanner, using 18F Fluorodeoxyglucose (FDG) to measure cerebral glucose metabolism. Following imaging evaluation at 2 months, subjects initially attributed to the standard of care arm were eligible for treatment with NAC. Clinical and symptom questionnaires were also completed initially and after 2 months.

Results: The FDG PET data showed significantly increased cerebral glucose metabolism in several brain regions including the caudate, inferior frontal gyrus, lateral temporal gyrus, and middle temporal gyrus (p < 0.05) in the MS group treated with NAC, as compared to the control group. Self-reported scores related to cognition and attention were also significantly improved in the NAC group as compared to the control group.

Conclusions: The results of this study suggest that NAC positively affects cerebral glucose metabolism in MS patients, which is associated with qualitative, patient reported improvements in cognition and attention. Larger scale studies may help to determine the clinical impact of NAC on measures of functioning over the course of illness, as well as the most effective dosage and dosage regimen.

Retrospective Evaluation of Clinical Experience With Intravenous Ascorbic Acid in Patients With Cancer

BACKGROUND

Intravenous ascorbic acid (IV AA) has been used extensively in cancer patients throughout the United States. Currently, there are limited data on the safety and clinical effects of IV AA. The purpose of this study was to expand the current literature using a retrospective analysis of adverse events and symptomatic changes of IV AA in a large sample of cancer patients.

METHODS

We conducted a retrospective chart review of all patients receiving IV AA for cancer at the Thomas Jefferson University Hospital over a 7-year period. We assessed all reports of adverse events, laboratory findings, and hospital or emergency department admissions. We also reviewed quality-of-life data, including fatigue, nausea, pain, appetite, and mood.

RESULTS

There were 86 patients who received a total of 3034 doses of IV AA ranging from 50 to 150g. In all, 32 patients received only ascorbic acid as part of their cancer management (1197 doses), whereas 54 patients received ascorbic acid in conjunction with chemotherapy (1837 doses). The most common adverse events related to ascorbic acid were temporary nausea and discomfort at the injection site. All events reported in the ascorbic acid alone group were associated with less than 3% of the total number of infusions. Patients, overall, reported improvements in fatigue, pain, and mood while receiving ascorbic acid.

CONCLUSIONS

The results of this retrospective analysis support the growing evidence that IV AA is generally safe and well tolerated in patients with cancer, and may be useful in symptom management and improving quality of life.

Changes in cerebellar functional connectivity and autonomic regulation in cancer patients treated with the Neuro Emotional Technique for traumatic stress symptoms

PURPOSE

A growing number of research studies have implicated the cerebellum in emotional processing and regulation, especially with regard to negative emotional memories. However, there currently are no studies showing functional changes in the cerebellum as a result of treatment for traumatic stress symptoms. The Neuro Emotional Technique (NET) is an intervention designed to help improve symptoms related to traumatic stress using an integrative approach that combines emotional, cognitive, and motor processing, with a particular focus on autonomic nervous system regulation. In this study, we evaluated whether the NET intervention alters functional connectivity in the brain of patients with traumatic stress symptoms associated with a cancer-related event. We hypothesized that the NET intervention would reduce emotional and autonomic reactivity and that this would correlate with connectivity changes between the cerebellum and limbic structures as well as the brain stem.

METHODS

We enrolled patients with a prior cancer diagnosis who experienced distressing cancer-related memories associated with traumatic stress symptoms of at least 6 months in duration. Participants were randomized to either the NET intervention or a waitlist control. To evaluate the primary outcome of neurophysiological effects, all participants received resting-state functional blood oxygen level-dependent (BOLD) magnetic resonance imaging (rs-fMRI) before and after the NET intervention. In addition, autonomic reactivity was measured using heart rate response to the traumatic stimulus. Pre/post comparisons were performed between the NET and control groups.

RESULTS

The results demonstrated significant changes in the NET group, as compared to the control group, in the functional connectivity between the cerebellum (including the vermis) and the amygdala, parahippocampus, and brain stem. Likewise, participants receiving the NET intervention had significant reductions in autonomic reactivity based on heart rate response to the traumatic stimulus compared to the control group.

CONCLUSIONS

This study is an initial step towards establishing a neurological signature of treatment effect for the NET intervention. Specifically, functional connectivity between the cerebellum and the amygdala and prefrontal cortex appear to be associated with a reduction in autonomic reactivity in response to distressing cancer-related memories.

IMPLICATIONS FOR CANCER SURVIVORS

This study contributes to the understanding of possible mechanisms by which interventions like NET may help reduce emotional distress in cancer patients who suffer from traumatic stress symptoms.

Neuro emotional technique effects on brain physiology in cancer patients with traumatic stress symptoms: preliminary findings

PURPOSE

The purpose of this study was to characterize the neurophysiological and clinical effects that may result from the neuro emotional technique (NET) in patients with traumatic stress symptoms associated with a cancer-related event. We hypothesized that self-regulatory processing of traumatic memories would be observable as physiological changes in key brain areas after undergoing the NET intervention and that these changes would be associated with improvement of traumatic stress symptoms.

METHODS

We enrolled 23 participants with a prior cancer diagnosis who expressed a distressing cancer-related memory that was associated with traumatic stress symptoms of at least 6 months in duration. Participants were randomized to either the NET intervention or a waitlist control condition. To evaluate the primary outcome of neurophysiological effects, all participants received functional magnetic resonance imaging (fMRI) during the auditory presentation of both a neutral stimulus and a description of the specific traumatic event. Pre/post-comparisons were performed between the traumatic and neutral condition, within and between groups. Psychological measures included the Impact of Event Scale (IES), State Trait Anxiety Index (STAI), Brief Symptom Inventory (BSI)-18, and Posttraumatic Cognitions Inventory (PTCI).

RESULTS

The initial fMRI scans in both groups showed significant increases in the bilateral parahippocampus and brainstem. After NET, reactivity in the parahippocampus, brainstem, anterior cingulate, and insula was significantly decreased during the traumatic stimulus. Likewise, participants receiving the NET intervention had significant reductions (p < 0.05) compared to the control group in distress as measured by the BSI-18 global severity index, anxiety as measured by the STAI, and traumatic stress as measured by the IES and PTCI.

CONCLUSIONS

This study is an initial step towards understanding mechanistic features of the NET intervention. Specifically, brain regions involved with traumatic memories and distress such as the brainstem, insula, anterior cingulate gyrus, and parahippocampus had significantly reduced activity after the NET intervention and were associated with clinical improvement of symptoms associated with distressing recollections.

IMPLICATIONS FOR CANCER SURVIVORS

This preliminary study suggests that the NET intervention may be effective at reducing emotional distress in patients who suffer from traumatic stress symptoms associated with a cancer-related event.

Clinical comparison of 99mTc exametazime and 123I Ioflupane SPECT in patients with chronic mild traumatic brain injury

Background

This study evaluated the clinical interpretations of single photon emission computed tomography (SPECT) using a cerebral blood flow and a dopamine transporter tracer in patients with chronic mild traumatic brain injury (TBI). The goal was to determine how these two different scan might be used and compared to each other in this patient population.

Methods and Findings

Twenty-five patients with persistent symptoms after a mild TBI underwent SPECT with both ^99mTc exametazime to measure cerebral blood flow (CBF) and ¹²³I ioflupane to measure dopamine transporter (DAT) binding. The scans were interpreted by two expert readers blinded to any case information and were assessed for abnormal findings in comparison to 10 controls for each type of scan. Qualitative CBF scores for each cortical and subcortical region along with DAT binding scores for the striatum were compared to each other across subjects and to controls. In addition, symptoms were compared to brain scan findings. TBI patients had an average of 6 brain regions with abnormal perfusion compared to controls who had an average of 2 abnormal regions (p<0.001). Patient with headaches had lower CBF in the right frontal lobe, and higher CBF in the left parietal lobe compared to patients without headaches. Lower CBF in the right temporal lobe correlated with poorer reported physical health. Higher DAT binding was associated with more depressive symptoms and overall poorer reported mental health. There was no clear association between CBF and DAT binding in these patients.

Conclusions

Overall, both scans detected abnormalities in brain function, but appear to reflect different types of physiological processes associated with chronic mild TBI symptoms. Both types of scans might have distinct uses in the evaluation of chronic TBI patients depending on the clinical scenario.

Meditation and neurodegenerative diseases

Neurodegenerative diseases pose a significant problem for the healthcare system, doctors, and patients. With an aging population, more and more individuals are developing neurodegenerative diseases and there are few treatment options at the present time. Meditation techniques present an interesting potential adjuvant treatment for patients with neurodegenerative diseases and have the advantage of being inexpensive, and easy to teach and perform. There is increasing research evidence to support the application of meditation techniques to help improve cognition and memory in patients with neurodegenerative diseases. This review discusses the current data on meditation, memory, and attention, and the potential applications of meditation techniques in patients with neurodegenerative diseases.

Change over time in brain serotonin transporter binding in major depression: effects of therapy measured with [(123) I]-ADAM SPECT

Several studies have reported low brain serotonin transporter (SERT) binding in individuals with major depression. We hypothesized that the SERT standardized uptake ratio (SUR) values using [(123) I]-ADAM single photon emission computed tomography would increase in depressed subjects who responded to cognitive behavior therapy (CBT) compared to CBT nonresponders. [(123) I]-ADAM scans were acquired before and after 12 weeks of CBT from 20 depressed subjects and on two occasions 12 weeks apart from 10 nondepressed, healthy volunteers. The primary outcome measure was change over time in SUR values in the midbrain, medial temporal lobe, and basal ganglia regions. Depressed subjects demonstrated low pretreatment mean SUR values that significantly increased over time in the midbrain (P = .011), right medial temporal lobe (P = .008), and left medial temporal lobe (P = .000) regions. Treatment responders showed a significant increase over time in SUR values in left medial temporal lobe (P = .029) and right medial temporal lobe (P = .007) regions. Partial and nonresponder subjects also showed a significant increase over time in SUR values in the left medial temporal region (P = .040) (vs. healthy volunteers), but to a lesser degree. The findings suggest that low pretreatment SERT binding may increase over time in some depressed individuals who experience symptom improvement.

Changes in cerebral blood flow and anxiety associated with an 8-week mindfulness programme in women with breast cancer

This study employed functional magnetic resonance imaging to evaluate changes in cerebral blood flow (CBF) associated with the Mindfulness-based Art Therapy (MBAT) programme and correlate such changes to stress and anxiety in women with breast cancer. Eighteen breast cancer patients were randomized to the MBAT or education control group. The patients received the diagnosis of breast cancer between 6 months and 3 years prior to enrollment and were not in active treatment. The age of participants ranged from 52 to 77 years. A voxel-based analysis was performed to assess differences at rest, during meditation and during a stress task. The anxiety sub-scale of the Symptoms Checklist-90-Revised was compared with changes in resting CBF before and after the programmes. Subjects in the MBAT arm demonstrated significant increases in CBF at rest and during meditation in multiple limbic regions, including the left insula, right amygdala, right hippocampus and bilateral caudate. Patients in the MBAT programme also had a significant correlation between increased CBF in the left caudate and decreased anxiety scores. In the MBAT group, responses to a stressful cue resulted in reduced activation of the posterior cingulate. The results demonstrate that the MBAT programme was associated with significant changes in CBF, which correlated with decreased anxiety over an 8-week period.

Initial clinical comparison of 18F-florbetapir and 18F-FDG PET in patients with Alzheimer disease and controls

The purpose of this study was to determine how clinical interpretations of the (18)F-amyloid tracer florbetapir compares diagnostically with (18)F-FDG PET when evaluating patients with Alzheimer disease (AD) and controls.

METHODS

Nineteen patients with a clinical diagnosis of AD and 21 elderly controls were evaluated with both (18)F-florbetapir and (18)F-FDG PET scans. Scans were interpreted together by 2 expert readers masked to any case information and were assessed for tracer binding patterns consistent with AD. The criteria for interpreting the (18)F-florbetapir scan as positive for AD was the presence of binding in the cortical regions relative to the cerebellum. (18)F-FDG PET scans were interpreted as positive if they displayed the classic pattern of hypometabolism in the temporoparietal regions. Scans were interpreted as either positive or negative for AD. In addition, a relative scoring system was used to assess the degree of either hypometabolism or amyloid binding in specified regions. The metabolism and amyloid binding scores for each region were compared across subjects. An overall ratio was calculated on the basis of values in regions expected to be affected by AD and those not expected to be affected. The metabolic ratio and amyloid ratio were then correlated with the mini-mental status examination (MMSE) score.

RESULTS

The sensitivity and specificity, compared with the clinical diagnosis of AD or controls, for the (18)F-florbetapir scans were 95% and 95%, respectively, and for the (18)F-FDG scans 89% and 86%, respectively. When a comparison with MMSE scores was made, (18)F-FDG significantly correlated with MMSE when both controls and AD patients were included (r = 0.79, P < 0.0001) and in AD patients alone (r = 0.70, P = 0.001). The (18)F-florbetapir scores significantly correlated with MMSE scores only when both controls and AD patients were included (r = 0.62, P < 0.001) but not in the AD group alone (r = 0.12, P = 0.66).

CONCLUSION

Overall, both scans performed well in detecting AD in patients with known clinical AD. Both scans correlated well with cognitive status as determined by MMSE when the entire cohort of controls and AD patients was evaluated. However, only the (18)F-FDG scans correlated with cognitive status when AD patients were evaluated separately.

Meditation effects on cognitive function and cerebral blood flow in subjects with memory loss: a preliminary study

This preliminary study determined if subjects with memory loss problems demonstrate changes in memory and cerebral blood flow (CBF) after a simple 8-week meditation program. Fourteen subjects with memory problems had an IV inserted and were injected with 250 MBq of Tc-99m ECD while listening to a neutral stimulus CD. They then underwent a pre-program baseline SPECT scan. Then subjects were guided through their first meditation session with a CD, during which they received an injection of 925 MBq ECD, and underwent a pre-program meditation scan. Subjects completed an 8-week meditation program and underwent the same scanning protocol resulting in a post-program baseline and meditation scan. A region of interest (ROI) template obtained counts in each ROI normalized to whole brain to provide a CBF ratio. Baseline and meditation scans and neuropsychological testing were compared before and after the program. The meditation program resulted in significant increases (p< 0.05) in baseline CBF ratios in the prefrontal, superior frontal, and superior parietal cortices. Scores on neuropsychological tests of verbal fluency, Trails B, and logical memory showed improvements after training. This preliminary study evaluated whether an 8-week meditation program resulted in improvements in neuropsychological function and differences in CBF in subjects with memory loss. While the findings are encouraging, there are a number of limitations that can be addressed in future studies with more participants and more detailed analyses.

Differences in serotonin transporter binding affinity in patients with major depressive disorder and night eating syndrome

OBJECTIVE

We examined serotonin transporter (SERT) binding affinity using single photon emission computed tomography (SPECT) in patients with major depressive disorder (MDD) and night eating syndrome (NES). There are similarities between MDD and NES in affective symptoms, appetite disturbance, nighttime awakenings, and, particularly, response to selective serotonin reuptake inhibitors (SSRIs).

METHODS

Six non-depressed patients with NES and seven patients with MDD underwent SPECT brain imaging with 123I-ADAM, a radiopharmaceutical agent selective for SERT sites. Uptake ratios of 123I-ADAM SERT binding were obtained for the midbrain, basal ganglia, and temporal lobe regions compared to the cerebellum reference region.

RESULTS

Patients with NES had significantly greater SERT uptake ratios (effect size range 0.64-0.84) in the midbrain, right temporal lobe, and left temporal lobe regions than those with MDD whom we had previously studied.

CONCLUSIONS

Pathophysiological differences in SERT uptake between patients with NES and MDD suggest these are distinct clinical syndromes.

Cerebral blood flow effects of yoga training: preliminary evaluation of 4 cases

OBJECTIVES

Experienced practitioners of yoga have been shown to alter brain function, but this case series measured cerebral blood flow before and after a 12-week training program in Iyengar yoga (IY) for naïve subjects.

METHODS

On the first day, each of the 4 subjects listened to the teacher speaking on the history and background of the yoga program while they were injected with 250 MBq of (99m)Tc-bicisate and received a single photon emission computed tomography scan (pre-program baseline). Subjects then had their first IY training and were injected and scanned with 925 MBq bicisate while they did their first meditation (pre-program meditation). Subjects then underwent a 12-week training program in IY and then underwent the same imaging protocol with a postprogram baseline and postprogram meditation scan. Baseline and meditation scans, before and after training, were compared using paired t tests.

RESULTS

There were significant decreases (p < 0.05) between the pre- and postprogram baseline scans in the right amygdala, dorsal medial cortex, and sensorimotor area. There was a significant difference (p < 0.05) in the pre- and postprogram percentage change (i.e., activation) in the right dorsal medial frontal lobe, prefrontal cortex, and right sensorimotor cortex.

CONCLUSIONS

These initial findings suggest the brain experiences a "training effect" after 12 weeks of IY training.

Measurement of regional cerebral blood flow associated with the M technique-light massage therapy: a case series and longitudinal study using SPECT

OBJECTIVES

The aim of this 2-study research project was to measure the physiologic effect of the M technique (see Appendix for description) on the brain using single photon emission computed tomography (SPECT) and compare it to conventional massage therapy.

METHODS

In the first study, 4 participants received 1 M technique session. Each participant was injected through the intravenous cannula (IV) with 7 mCi (99m)Tc and scanned using SPECT before the M technique session, and then was injected with 25 mCi (99m)Tc through the IV and scanned using SPECT after the M technique session. In the second study, 1 participant received 10 conventional (Swedish) massages and one participant received 10 M technique sessions. Both participants were injected and scanned (using the identical scanning parameters as in Study 1) before, and immediately after, their 1st and 10th sessions. Baseline and 1st, and baseline and 10th sessions were compared using paired t tests.

RESULTS

Although the activation changes were positively correlated for the M technique and massage participants (r = 27, p < 0.05), when activation changes around the 1st and around the 10th sessions were compared (using paired t tests), significant differences emerged. There were significant activation changes for the M technique participant [t(64) = 2.32, p < 0.05): In particular, there was a 40% activation change and directional change in regional cerebral blood flow in the right caudate, which was not seen in the massage participant. The precuneus showed an approximate 15% reduction in activation changes around the M technique session for both the 1st and 10th treatment, but not for the massage participant.

CONCLUSIONS

These findings suggest that the M technique and conventional massage may both elicit blood flow brain activation changes; however, the participants' responses did differ. The M technique revealed greater changes (particular in the right caudate), and these responses increased when the M technique was repeated over time (unlike massage). These findings have implications for future research into the potential mechanism of the M technique in the treatment and care of patients.

Dopamine transporter levels in cocaine dependent subjects

Cocaine use is a significant problem in the US and it is well established that cocaine binds to the dopamine transporter (DAT) in the brain. This study was designed to determine if the DAT levels measured by 99mTc TRODAT SPECT (single photon emission computed tomography) brain scans are altered in cocaine dependent subjects and to explore clinical correlates of such alterations. SPECT brain scans were acquired on 21 cocaine dependent subjects and 21 healthy matched controls. There were significantly higher DAT levels in cocaine dependent subjects compared to controls for the anterior putamen (p=0.003; Cohen's d effect size=0.98), posterior putamen (p<0.001; effect size=1.32), and caudate (p=0.003; effect size=0.97). DAT levels in these regions were 10%, 17%, and 8% higher in the cocaine dependent subjects compared to controls. DAT levels were unrelated to craving, severity of cocaine use, or duration of cocaine use, but DAT levels in the caudate and anterior putamen were significantly (p<0.05) negatively correlated with days since last use of cocaine.

Dopamine Transporter Binding in Smokers and Nonsmokers

PURPOSE

Regional brain concentrations of dopamine transporters have been examined to elucidate the neurochemical substrates of neurologic and psychiatric conditions. Many of these conditions are associated with increased (or decreased) cigarette smoking prevalence; therefore, current smoking may confound the results of these investigations. This study determined whether healthy current smokers and nonsmokers exhibit differences in dopamine transporter (DAT) binding measured by Tc-99m TRODAT SPECT.

MATERIALS AND METHODS

Tc-99m TRODAT SPECT brain scans were retrospectively evaluated in 46 nonsmokers and 8 current smokers, all of whom had been recruited and screened as healthy controls for previous imaging studies. The scans were acquired approximately 3 hours after the intravenous administration of 740 MBq (20 mCi) of Tc-99m TRODAT and were reconstructed with a simple bandpass filter. Regions of interest (ROIs) were placed manually on subregions of the right and left basal ganglia and distribution volume ratios (DVRs) were compared for the smoker and nonsmoker groups.

RESULTS

There were significant decreases in DAT binding in current smokers compared with nonsmokers in the caudate nuclei bilaterally, the right anterior putamen and the left posterior putamen.

CONCLUSION

Reduced DAT binding in ROIs relevant to movement disorders as well as other neuropsychiatric conditions may have important implications for evaluating scans in these patient populations.

Age-Related Structural and Metabolic Changes in the Pelvic Reproductive End Organs

In this work, we provide preliminary data and a review of the literature regarding normal structural and functional changes that occur in the aging uterus, ovary, testicle, and prostate gland. It is expected that such knowledge will help physicians to distinguish physiologic changes from pathologic changes at an early stage. We retrospectively reviewed pelvic magnetic resonance imaging (MRI) scans of 131 female and 79 male subjects ages 13 to 86 years to determine changes in volume of the uterus, ovary, and prostate gland with age. Scrotal ultrasound examinations of 150 male subjects ages 0 to 96 years also were analyzed retrospectively to determine changes in testicular volume with age. In addition, (18)F-fluorodeoxyglucose positron emission tomography ((18)F-FDG-PET) scans of 145 male subjects ages 11 to 90 years were analyzed retrospectively to assess for changes in maximum standardized uptake value (SUV(max)) of the testicles with age. The uterus had a mean volume of 38.55 +/- 3.68 cm(3) at 17 to 19 years of age, increased to a peak volume of 71.76 +/- 19.81 cm(3) between 35 to 40 years, and then declined to 24.02 +/- 8.11 cm(3) by the eighth decade of life. The maximal ovarian volume per subject maintained a relatively stable size in early life, measuring 9.46 +/- 3.25 cm(3) during the second decade of life, 8.46 +/- 3.32 cm(3) in the mid-fourth decade of life, and 7.46 +/- 3.33 cm(3) at 45 years of age, after which it declined to 4.44 +/- 2.02 cm(3) by the late fifth decade of life. The ovaries were not identifiable on MRI in subjects beyond the sixth decade of life. The volume of the prostate increased from 23.45 +/- 6.20 cm(3) during the second decade of life to 47.5 +/- 41.59 cm(3) by the late eighth decade of life; the central gland of the prostate increased from 9.96 +/- 3.99 cm(3) to 29.49 +/- 28.88 cm(3) during the same age range. Mean testicular volume was 11.2 +/- 5.9 cm(3). Testicular volume increased with age from birth to 25 years. After age 25, there was a significant decline in the testicular volume. The mean SUV(max) for the testicles was 1.9 +/- 0.5. Testicular metabolic activity demonstrated an increasing trend until the age of 35 years. A plateau in SUV(max) was observed after the age of 35 years until the age of 65 years. A slight decrease in SUV(max) was observed after the age of 65 years. The pelvic structures of men and women change both structurally and functionally over the lifespan, and such changes can be quantified using ultrasound, MRI, and (18)F-FDG-PET.

[99mTc]TRODAT-1 SPECT imaging correlates with odor identification in early Parkinson disease

BACKGROUND

In vivo imaging of the dopamine transporter with [99mTc]TRODAT-1 (TRODAT) and olfactory testing have both been proposed as potential biomarkers in Parkinson disease (PD).

OBJECTIVE

To evaluate the relationship between TRODAT SPECT imaging, odor identification skills, and motor function in patients with early PD.

METHODS

Twenty-four patients with a clinical diagnosis of early-stage PD (mean Hoehn & Yahr stage = 1.4) underwent TRODAT imaging, Unified PD Rating Scale (UPDRS) ratings of motor function, and administration of the University of Pennsylvania Smell Identification Test (UPSIT). Brain images were obtained using a standardized processing protocol and specific uptake ratios for striatal regions of interest were calculated. Partial correlations between the imaging indices, disease duration, UPSIT scores, and UPDRS motor scores were then calculated.

RESULTS

UPSIT scores were correlated with TRODAT uptake in the striatum as a whole (r = 0.66, p = 0.001). The putamen showed the strongest correlation with the UPSIT (r = 0.74; p < 0.001). The correlation between dopamine transporter density in the caudate and UPSIT was moderate (r = 0.36, p = 0.11), but was not significant.

CONCLUSIONS

Olfactory function is highly correlated with dopamine transporter imaging abnormalities in early Parkinson disease (PD). Further studies are warranted to determine whether changes over time in these two measures are also correlated in early PD.

Concurrent CBF and CMRGlc changes during human brain activation by combined fMRI–PET scanning

A novel approach for concurrent measurement of regional cerebral blood flow (CBF) and regional cerebral metabolic rate for glucose consumption (CMRGlc) in humans is proposed and validated in normal subjects during visual stimulation. 18F-labeled fluorodeoxyglucose was administered during the measurement of CBF by continuous arterial spin labeled magnetic resonance imaging (MRI). Subsequent positron emission tomographic (PET) scanning demonstrated the distribution of labeled deoxyglucose during the MRI acquisition. An excellent concordance between regional CBF and regional CMRGlc during visual stimulation was found, consistent with previously published PET findings. Although initially validated using a brief, non-quantitative protocol, this approach can provide quantitative CBF and CMRGlc, with a broad range of potential applications in functional physiology and pathophysiology.

123I-ADAM binding to serotonin transporters in patients with major depression and healthy controls: a preliminary study

The serotonergic system may play an important role in the pathophysiology of major depressive disorder (MDD). Few imaging studies have examined serotonin transporter (SERT) binding in patients with MDD. We hypothesized that SERT binding activity may be altered in patients with MDD. This study compared SERT binding in patients with MDD with that in healthy controls.

METHODS

We studied SERT activity in 7 patients (22-50 y old) with moderate to severe MDD and 6 healthy controls (24-56 y old) using (123)I-labeled 2-((2-((dimethylamino)methyl) phenyl)thio)-5-iodophenylamine (ADAM) and SPECT brain imaging. Subjects underwent SPECT 4 h after intravenous administration of 185 MBq (5 mCi) of (123)I-ADAM. Images were reconstructed in the axial plane, and region-of-interest demarcations were placed on the midbrain, medial temporal region, and basal ganglia region.

RESULTS

(123)I-ADAM binding to SERT in the midbrain was significantly lower (P = 0.01) in MDD patients (1.81 +/- 0.07) than in controls (1.95 +/- 0.13). Age-adjusted (123)I-ADAM binding in the midbrain correlated significantly with scores on the Hamilton Depression Rating Scale (r = 0.82; P = 0.02). A significant negative correlation was observed between (123)I-ADAM SERT binding in the midbrain and age in the healthy control group (r = 0.98; P = 0.0002). SERT binding in the basal ganglia or medial temporal regions of interest did not significantly differ between groups.

CONCLUSION

The findings from this preliminary study suggest the possibility of decreased SERT binding in the midbrain region of patients with MDD, with the degree of decrease correlating with the severity of depressive symptoms. There also appears to be an age-related decline in midbrain (123)I-ADAM SERT binding in healthy subjects.

Differences in [99mTc]TRODAT-1 SPECT binding to dopamine transporters in patients with multiple system atrophy and Parkinson's disease

PURPOSE

Multiple system atrophy (MSA), a disorder causing autonomic dysfunction, parkinsonism, and cerebellar dysfunction, is difficult to differentiate from other movement disorders, particularly early in the course of disease. This study evaluated whether [99mTc]TRODAT-1 binding to the dopamine transporter differentiates MSA from other movement disorders.

METHODS

Single-photon emission computed tomographic brain scans were acquired in 25 MSA patients, 48 age-matched controls, and 130 PD patients, 3 h after the injection of 740 MBq (20 mCi) of [99mTc]TRODAT-1. Regions of interest (ROIs) were placed manually on subregions of both basal ganglia and distribution volume ratios (DVRs) were calculated. Regional DVRs were compared between study groups in MSA patients. Student's t tests were used to compare MSA patients with other study groups. Spearman correlations were used to compare DVRs with NP measures.

RESULTS

Based upon various motor scores, MSA and PD patients had comparable motor impairment, and were significantly impaired compared with controls. Mean DVRs in the basal ganglia of MSA patients were significantly less than those of controls, but generally higher (p<0.05) than in PD patients. In particular, the MSA patients had significantly increased DVRs in the posterior putamen (mean 0.49+/-0.30) compared with PD patients (0.74+/-0.25).

CONCLUSION

Movement disorder patients could be differentiated from controls, but MSA and PD patients could not be easily differentiated from each other. As a group, MSA patients had significantly higher mean [99mTc]TRODAT-1 binding, particularly in the posterior putamen, compared with PD patients and significantly lower binding compared with controls. This may reflect different pathophysiological processes of the two neurodegenerative diseases.

Biodistribution and imaging with (123)I-ADAM: a serotonin transporter imaging agent

2-((2-((Dimethylamino)methyl)phenyl)thio)-5-(123)I-iodophenylamine ((123)I-ADAM) is a new radiopharmaceutical that selectively binds the central nervous system serotonin transporters. The purpose of this study was to measure its whole-body biokinetics and estimate its radiation dosimetry in healthy human volunteers. The study was conducted within a regulatory framework that required its pharmacologic safety to be assessed simultaneously.

METHODS

The sample included 7 subjects ranging in age from 22 to 54 y old. An average of 12.7 whole-body scans were acquired sequentially on a dual-head camera for up to 50 h after the intravenous administration of 185 MBq (5 mCi) (123)I-ADAM. The fraction of the administered dose in 13 regions of interest (ROIs) was quantified from the attenuation-corrected geometric mean counts in conjugate views. Multiexponential functions were iteratively fit to each time-activity curve using a nonlinear, least-squares regression algorithm. These curves were numerically integrated to yield source organ residence times. Gender-specific radiation doses were then estimated with the MIRD technique. SPECT brain scans obtained 3 h after injection were evaluated using an ROI analysis to determine the range of values for the region to cerebellum.

RESULTS

There were no pharmacologic effects of the radiotracer on any of the subjects, including no change in heart rate, blood pressure, or laboratory results. Early planar images showed differentially increased activity in the lungs. SPECT images demonstrated that the radiopharmaceutical localized in the midbrain in a distribution that is consistent with selective transporter binding. The dose-limiting organ in both men and women was the distal colon, which received an average of 0.12 mGy/MBq (0.43 rad/mCi) (range, 0.098-0.15 mGy/MBq). The effective dose equivalent and effective dose for (123)I-ADAM were 0.037 +/- 0.003 mSv/MBq and 0.036 +/- 0.003 mSv/MBq, respectively. The mean adult male value of effective dose for (123)I-ADAM is similar in magnitude to that of (111)In-diethylenetriaminepentaacetic acid (0.035 mGy/MBq), half that of (111)In-pentetreotide (0.81 mGy/MBq), and approximately twice that of (123)I-inosine 5'-monophosphate (0.018 mGy/MBq). The differences in results between this study and a previous publication are most likely due to several factors, the most prominent being this dataset used attenuation correction of the scintigraphic data. Region-to-cerebellum ratios for the brain SPECT scans were 1.95 +/- 0.13 for the midbrain, 1.27 +/- 0.10 for the medial temporal regions, and 1.11 +/- 0.07 for the striatum.

CONCLUSION

(123)I-ADAM may be a safe and effective radiotracer for imaging serotonin transporters in the brain and the body.