The use of single photon emission computed tomography in depressive disorders

Effects of a probiotic add-on treatment on fronto-limbic brain structure, function, and perfusion in depression: Secondary neuroimaging findings of a randomized controlled trial

BACKGROUND

Probiotics are suggested to improve depressive symptoms via the microbiota-gut-brain axis. We have recently shown a beneficial clinical effect of probiotic supplementation in patients with depression. Their underlying neural mechanisms remain unknown.

METHODS

A multimodal neuroimaging approach including diffusion tensor imaging, resting-state functional MRI, and arterial spin labeling was used to investigate the effects of a four-weeks probiotic supplementation on fronto-limbic brain structure, function, and perfusion and whether these effects were related to symptom changes.

RESULTS

Thirty-two patients completed both imaging assessments (18 placebo and 14 probiotics group). Probiotics maintained mean diffusivity in the left uncinate fasciculus, stabilized it in the right uncinate fasciculus, and altered resting-state functional connectivity (rsFC) between limbic structures and the temporal pole to a cluster in the precuneus. Moreover, a cluster in the left superior parietal lobule showed altered rsFC to the subcallosal cortex, the left orbitofrontal cortex, and limbic structures after probiotics. In the probiotics group, structural and functional changes were partly related to decreases in depressive symptoms.

LIMITATIONS

This study has a rather small sample size. An additional follow-up MRI session would be interesting for seeing clearer changes in the relevant brain regions as clinical effects were strongest in the follow-up.

CONCLUSION

Probiotic supplementation is suggested to prevent neuronal degeneration along the uncinate fasciculus and alter fronto-limbic rsFC, effects that are partly related to the improvement of depressive symptoms. Elucidating the neural mechanisms underlying probiotics' clinical effects on depression provide potential targets for the development of more precise probiotic treatments.

Effect of Low-Dose Statins in Addition to Standard Therapy on Brain Perfusion and Neurocognitive Performance in Patients with Major Depressive Disorder

INTRODUCTION

Major depressive disorder (MDD) is a prevalent condition which has a well-known association with ischemic cardiomyopathy, probably explained by an inflammatory mediator mechanism. Statins, besides reducing cholesterol production, have pleiotropic effects including anti-inflammatory activity. The goal was to evaluate the effect of statins as an addition to standard therapy on mood status, brain perfusion, and neurocognitive performance in MDD.

METHODS

We studied 20 MDD patients with brain single-photon emission tomography and Cambridge Neuropsychological Test Automated Battery (CANTAB), half randomized to 10 mg of Rosuvastatin or placebo, in addition to selective serotonin reuptake inhibitors (SSRIs) therapy and being reevaluated 3 months later. The images were compared using Statistical Parametric Mapping; clinical scores (Hamilton Depression Score with 17 items and Beck's Depression Inventory) as well as neurocognitive parameters were applied as covariances (CoV) to estimate regional cerebral blood flow (rCBF) changes with both therapies.

RESULTS

Clinical scores decreased in both groups (p = 0.0001); Beck's presented a larger decrease with statins. We observed significantly rCBF changes expressed as significant larger clusters of voxels (p < 0.05) in the pre/subgenual anterior cingulate plus orbitofrontal cortex and a small area in the posterior cingulate gyrus in the statins group, whereas it was not observed with placebo, when using clinical scores as CoV. A similar pattern of rCBF changes was present with emotions recognition, attentional, paired associates learning, spatial planning, and working memory tasks.

CONCLUSION

Short-term use of low-dose statins in MDD patients under SSRIs results in important rCBF changes in key mood associated areas to improvement in neurocognitive performance. These findings, even though demonstrated in a small sample, could open a new therapeutic tool in the comprehensive management of this disorder.

Cerebral blood flow in adolescents with drug-naive, first-episode major depressive disorder: An arterial spin labeling study based on voxel-level whole-brain analysis

Purpose

The major depressive disorder (MDD) can be a threat to the health of people all over the world. Although governments have developed and implemented evidence-based interventions and prevention programs to prevent MDD and maintain mental health in adolescents, the number of adolescents with this condition has been on the rise for the past 10 years.

Methods

A total of 60 adolescents were recruited, including 32 drug-naive adolescents with first-episode MDD and 28 healthy controls (HCs). Alterations in the intrinsic cerebral activity of the adolescents with MDD were explored using arterial spin labeling (ASL) while differences in the regional cerebral blood flow (rCBF) of the two groups were assessed based on voxel-based whole-brain analysis. Finally, correlations between the regional functional abnormalities and clinical variables were investigated for adolescents with MDD.

Results

Compared with HCs, MDD patients had a lower rCBF in the left triangular part of the inferior frontal gyrus (IFGtriang) but a higher one in the right Precental gyrus (PreCG). Negative correlations were also noted between the CBF in the left IFGtriang and the Hamilton depression scale (HAMD) scores of MDD patients.

Conclusion

Elucidating the neurobiological features of adolescent patients with MDD is important to adequately develop methods that can assist in early diagnosis, precaution and intervention.

Electroconvulsive Therapy Reverses Cerebral Hypoperfusion in a Patient With Psychotic Depression and Catatonia

ABSTRACT

A 72-year-old man suffering with severe depression with psychotic symptoms, marked apathy, and psychomotor retardation was treated with electroconvulsive therapy (ECT) after resistance to treatment with psychotropic medications. His age, comorbidities, and dysexecutive syndrome prompted consideration of a diagnosis of frontotemporal dementia (FTD), and a 99mTechnetium-labeled hexamethyl propylene amine oxime single-photon emission computed tomography (SPECT) brain perfusion scan showed bilateral perfusion defects that were most pronounced in the frontal regions of the brain. The scan was judged to be abnormal and in keeping with a neurodegenerative dementia. We reasoned that the fluctuation in symptoms was inconsistent with a diagnosis of FTD and that his severe depression could be improved with ECT even if he had FTD, so we decided to proceed with this treatment. A course of 12 sessions of ECT resulted in remission of his psychiatric symptoms and improvement in cognitive performance. A repeat SPECT scan 5 weeks after the last ECT demonstrated a substantial improvement in cerebral blood flow, favoring the diagnosis of depression, rather than dementia. Similar case reports from the literature suggest that ECT does reverse brain hypoperfusion in severe cases of depression and catatonia. Clinicians should be aware that abnormal SPECT findings are nonspecific and can be caused by various conditions, including psychiatric illness, and are not necessarily diagnostic of a neurodegenerative disease.

Sex differences in the blood-brain barrier: Implications for mental health

Prevalence of mental disorders, including major depressive disorder (MDD), bipolar disorder (BD) and schizophrenia (SZ) are increasing at alarming rates in our societies. Growing evidence points toward major sex differences in these conditions, and high rates of treatment resistance support the need to consider novel biological mechanisms outside of neuronal function to gain mechanistic insights that could lead to innovative therapies. Blood-brain barrier alterations have been reported in MDD, BD and SZ. Here, we provide an overview of sex-specific immune, endocrine, vascular and transcriptional-mediated changes that could affect neurovascular integrity and possibly contribute to the pathogenesis of mental disorders. We also identify pitfalls in current literature and highlight promising vascular biomarkers. Better understanding of how these adaptations can contribute to mental health status is essential not only in the context of MDD, BD and SZ but also cardiovascular diseases and stroke which are associated with higher prevalence of these conditions.

Regional Brain Perfusion Is Associated with Endothelial Dysfunction Markers in Major Depressive Disorder

BACKGROUND

Major depressive disorder (MDD) is an important independent risk factor for cardiovascular disease. Cumulative data suggest that depressive patients exhibit derangement in regional cerebral blood flow (rCBF), although underlying mechanisms remain mostly unknown. Endothelial dysfunction (ED), defined as different forms of abnormal endothelial activity, plays a key role in the pathogenesis of vascular disease. ED is associated with several clinical conditions characterized by high cardiovascular risk. Diverse ED markers have been found in mood disorders.

PURPOSE

To evaluate the association between rCBF and peripheral ED markers in MDD patients, at baseline and after selective serotonin receptor inhibitors (SSRIs) therapy.

PATIENTS AND METHODS

Twenty-seven untreated unipolar MDD patients in their first episode were evaluated with the Hamilton Depression Rating Scale (HAM-D) and brain perfusion SPECT at baseline and after 2 months of SSRIs. Statistical Parametric Mapping (SPM) was employed to evaluate rCBF; circulating endothelial cells (CECs), plasma soluble intercellular adhesion molecule (sICAM), and high-sensitivity C-reactive protein (hsCRP) were used as independent covariates.

RESULTS

Baseline CECs and sICAM were increased in MDD patients compared with matching controls (p = 0.0001) and hsCRP (p = 0.03). HAM-D scores (21 items) and CECs diminished after SSRI therapy in MDD patients (p < 0.0001). There was a significant rCBF decrease, mainly in deep central structures. HAM-D change was associated with rCBF decrease at the left amygdala, right striatum levels, and Brodmann area 25. CEC change was associated with rCBF at deep brain level and sICAM with large rCBF areas at the left caudate and tectum; hsCRP was associated, to a lesser extent, with the left dorsal striatum and mesencephalic tectum.

CONCLUSION

ED markers in patients with MDD are associated with significant changes in rCBF which are features of depression. These findings suggest that systemic damage/activation of the endothelium may contribute to the abnormal rCBF observed in MDD patients.

Spontaneous thought-related network connectivity predicts sertraline effect on major depressive disorder

Sertraline is one of the most commonly prescribed antidepressants. Major depressive disorder (MDD) is characterized by spontaneous thoughts that are laden with negative affect-a "malignant sadness". Prior neuroimaging studies have identified abnormal resting-state functional connectivity (rsFC) in the spontaneous brain networks of MDD patients. But how antidepressant medication acts to relieve the experience of depression as well as adjust its associated spontaneous networks and mood-regulation circuits remains an open question. In this study, we recruited 22 drug-naïve MDD patients along with 35 normal controls and investigated whether the functional integrity of cortical networks associated with spontaneous thoughts is modulated by sertraline treatment. We attempted to predict post-treatment effects based upon what we observed in the pre-treatment rsFC of drug-naïve MDD patients. In the result, we demonstrated that (1) after the sertraline treatment, the medial temporal lobe of default network (DN_MTL) and mood regulation pathway-the fronto-parietal control network (FPCN), the thalamus, and the salience network (SN)-were restored to normal connectivity, relative to the pre-treatment condition; however, the altered connections of FPCN-core DN (DN_CORE), FPCN-SN, and intra-FPCN among MDD patients remained impaired; (2) thalamo-prefrontal connectivity provides moderate predictive power (r² = 0.63) for the effectiveness of sertraline treatment. In summary, our findings contribute to a body of evidence that suggests salubrious effects of sertraline treatment primarily involve the FPCN-thalamus-SN pathway. The pre-treatment rsFC in this pathway could serve as a predictor of sertraline treatment outcome.

Regional Parieto-occipital Hypoperfusion on Arterial Spin Labeling Associates with Major Depressive Disorder

Background:

Reduced cerebral blood flow in parieto-occipital regions has been reported in neurodegenerative disorders using ASL. We aimed to investigate neuropsychiatric and neurodegenerative comorbidities that may associate with parieto-occipital region hypoperfusion.

Methods:

This was a retrospective single-center study. Between March 2017 to May 2018, adult patients who underwent brain MRI with the inclusion of ASL perfusion and who had bilateral reductions of CBF in the parieto-occipital regions were included. ASL was performed using a pseudo-continuous arterial spin labeling (pCASL) technique on 1.5T MR system. Age and gender-matched patients with no perfusion defect were concurrently collected. Comorbidity data was collected from EMR, including major depressive disorder, Alzheimer’s disease, Parkinson’s disease, Schizophrenia, anxiety disorder, hypertension, diabetes mellitus type II, coronary artery disease, and chronic kidney disease. A Pearson’s Chi-Square test was performed to assess for comorbidities associated with hypoperfusion of the parieto-occipital lobes.

Results:

Our patient cohort consisted of 93 patients with bilateral hypoperfusion in the parieto-occipital lobes and 93 age and gender-matched patients without corresponding perfusion defects based on ASL-CBF. Among the comorbidities assessed, there was a statistically significant association between hypoperfusion of the parieto-occipital lobes and major depressive disorder (p=0.004) and Parkinson’s disease (p=0.044). There was no statistically significant association for Alzheimer’s disease, generalized anxiety disorder, diabetes mellitus type II, hypertension, coronary artery disease, or chronic kidney disease.

Conclusion:

Major depressive disorder may be linked to regional parieto-occipital hypoperfusion on ASL.

Insomnia and Depression: Japanese Hospital Workers Questionnaire Survey

Objectives

This study aimed to identify a correlation between insomnia and the occurrence of depression among Japanese hospital employees using the data obtained from a self-reported questionnaire.

Methods

A self-administered questionnaire on sleeping patterns, depression, fatigue, lifestyle-related diseases, and chronic pain was given to 7690 employees aged 20-60 years, and 5,083 employees responded.

Results

An insomnia score of >2 was observed in 840 (13%) respondents. Chronic insomnia correlated significantly with gender, occupation, overtime work, metabolic syndrome, chronic pain, fatigue, and depression. Moreover, significant negative effects on depression scores were observed in males aged 30-39 (partial regression coefficient: b=0.357, p=0.016), females aged 20-29 (b=0.494, p<0.001), male administrative staff (b=0.475, p=0.003), males with metabolic syndrome (b=0.258, p=0.023), and both genders with chronic insomnia (male; b=0.480, p<0.001: female; b=0.485, p<0.001), and fatigue (male; b=1.180, p<0.001: female; b=1.151, p<0.001).

Discussion

Insomnia is a risk factor for depression and for other lifestyle-related diseases. The insomnia score may be useful in preventative care settings because it is associated with a wide spectrum of diseases and serves as a valuable marker for early detection of depression. Thus, our future studies will focus on establishing a method for early detection of depression symptoms among workers across various job profiles.

Cerebral blood flow changes in remitted early- and late-onset depression patients

Abnormal cerebral blood flow (CBF) is reportedly associated with major depressive disorder (MDD). We have investigated CBF changes in early-onset depression (EOD) and late-onset depression (LOD), and their impact on cognitive function. Thirty-two remitted EOD patients, 32 remitted LOD patients, and 43 age-matched healthy controls were recruited, and the pulsed arterial spin labeling data were scanned under 3.0T MRI and processed through voxel-by-voxel statistical analysis. Compared to healthy controls, LOD patients had decreased normalized CBF in the bilateral precuneus, cuneus, right fronto-cingulate-striatal areas, and right temporal, occipital and parietal lobes, but increased normalized CBF in the left frontal and temporal cortices and the cingulate gyrus. EOD patients had decreased normalized CBF in the left cerebellum and right calcarine/lingual/fusiform gyrus, and increased normalized CBF in right angular gyrus. LOD patients displayed hemispheric asymmetry in CBF, and had more regions with abnormal CBF than EOD patients. A significant correlation between abnormal CBF and impaired cognitive function was detected in LOD patients, but not EOD patients. These results demonstrate greater CBF abnormalities in LOD patients than EOD patients, and suggest these CBF changes may be associated with progressive degradation of cognitive function in LOD patients.

A Comparison of Neuroimaging Abnormalities in Multiple Sclerosis, Major Depression and Chronic Fatigue Syndrome (Myalgic Encephalomyelitis): is There a Common Cause?

There is copious evidence of abnormalities in resting-state functional network connectivity states, grey and white matter pathology and impaired cerebral perfusion in patients afforded a diagnosis of multiple sclerosis, major depression or chronic fatigue syndrome (CFS) (myalgic encephalomyelitis). Systemic inflammation may well be a major element explaining such findings. Inter-patient and inter-illness variations in neuroimaging findings may arise at least in part from regional genetic, epigenetic and environmental variations in the functions of microglia and astrocytes. Regional differences in neuronal resistance to oxidative and inflammatory insults and in the performance of antioxidant defences in the central nervous system may also play a role. Importantly, replicated experimental findings suggest that the use of high-resolution SPECT imaging may have the capacity to differentiate patients afforded a diagnosis of CFS from those with a diagnosis of depression. Further research involving this form of neuroimaging appears warranted in an attempt to overcome the problem of aetiologically heterogeneous cohorts which probably explain conflicting findings produced by investigative teams active in this field. However, the ionising radiation and relative lack of sensitivity involved probably preclude its use as a routine diagnostic tool.

Pseudo-continuous arterial spin labeling imaging of cerebral blood perfusion asymmetry in drug-naïve patients with first-episode major depression

Many previous studies have reported that regional cerebral blood flow (rCBF) aberrations may be one of the pathological characteristics of depression and rCBF has demonstrated a certain degree of asymmetry. However, studies investigating the cerebral blood perfusion asymmetry changes of drug-naïve patients experiencing their first episode of major depression using pseudo-continuous arterial spin labeling (pCASL) are rare. Ten drug-naïve patients experiencing their first major depression episode and 15 healthy volunteers were enrolled in the current study. A novel pCASL method was applied to whole brain MRI scans of all of the samples. The Statistics Parameter Mapping and Relative Expression Software Tool software packages were used for the pre-processing and statistical analysis of the two sets of images, and the differences in the cerebral blood perfusion at the whole brain level were compared between the two groups. Compared with the healthy control group, the cerebral perfusion of the depression patients showed an asymmetric pattern. Decreased cerebral blood perfusion regions were primarily located in the left hemisphere, specifically in the left temporal lobe, frontal lobe and cingulate cortex [P<0.05 and cluster size ≥30 with false discovery rate (FDR) correction]. Simultaneously, increased perfusion regions were predominantly located in the right hemisphere, specifically in the right cerebellum, thalamus, frontal lobe and anterior cingulate cortex (P<0.05 and cluster size ≥30, with FDR correction). Thus, pCASL may characterize the alterations in cerebral blood perfusion of patients with depression.

Changes in regional cerebral blood flow with Chaihu-Shugan-San in the treatment of major depression

Background:

Chaihu-Shugan-San (CHSGS) is a well-known Chinese traditional prescription used for depression.

Objective:

To observe the regional cerebral blood flow (rCBF) changes in patients with major depression and to investigate rCBF and clinical response to CHSGS.

Materials and Methods:

A total of 33 unmedicated patients with major depression and 12 healthy comparison subjects underwent single photon emission computed tomography (SPECT) imaging. A total of 33 unmedicated patients with major depression all met the diagnostic criteria of stagnation of liver qi of traditional Chinese medicine and were divided into two groups: CHSGS group (n = 20) and fluoxetine group (n = 13). SPECT imaging was restudied in posttreatment.

Results:

SPECT detected abnormalities in all (100.0%) patients both in CHSGS group and fluoxetine group. All healthy subjects were normal results. The depressed patients showed rCBF decreased in the multiple regions. The semiquantitative values of bilateral frontal and left temporal lobes both in CHSGS group and fluoxetine group were lower than that in healthy group (P < 0.05). Reexamined SPECT after 8 weeks treatment with CHSGS showed the consistency between the increase in perfusion defects and the improvement of clinical cerebral symptoms. The semiquantitative values increased in posttreatment, when compared with pretreatment (P < 0.05).

Conclusion:

SPECT represents a sensitive tool to detect the major depressive disorder, which show the rCBF decreased. rCBF perfusion defects can be reversed and clinical symptoms can be improved by CHSGS treatment. CHSGS treatment is effective, well-tolerated, and safe for depression. By semiquantitative analysis, SPECT can objectively detect rCBF changes that is useful for guiding treatment.

Characteristic distributions of regional cerebral blood flow changes in major depressive disorder patients: a pseudo-continuous arterial spin labeling (pCASL) study

BACKGROUND

Most previous studies that examined regional cerebral blood flow (rCBF) abnormalities in major depressive disorder (MDD) required the injection of radioisotopes into subjects. Here by using magnetic resonance imaging (MRI) with the pseudo-continuous arterial spin labeling (pCASL) method which does not require radioisotopes, we examined rCBF in patients with MDD in comparison with that in patients with schizophrenia and healthy subjects, taking the regional cerebral gray matter volume into account.

METHODS

Subjects were 27 patients with MDD, 42 with schizophrenia and 43 healthy volunteers who underwent 3-T MRI with pCASL. Obtained pCASL imaging data were subject to the voxel-by-voxel statistical analysis.

RESULTS

There were significant reductions of rCBF in the right inferior prefrontal cortex and anterior cingulate cortices (ACCs) in the MDD patients compared with the healthy controls. When compared with the schizophrenic patients, the MDD patients showed lower rCBF in the subgenual ACC and higher rCBF in left occipital region.

LIMITATION

The abnormalities of rCBF in MDD were known to reverse during symptom remission. Further study with follow-up period would bring the perception about the treatment response.

CONCLUSION

The rCBF reduction in the subgenual region may be a specific functional abnormality to MDD patients, which may provide a biological marker for MDD. The MRI with pCASL method is a promising tool to detect rCBF abnormalities controlling for gray matter volume in psychiatric disorders.

The role of cognitive group therapy and happiness training on cerebral blood flow using 99mTc-ECD brain perfusion SPECT: a quasi-experimental study of depressed patients

OBJECTIVE

The purpose of this study is to investigate the impact of cognitive group therapy and happiness training objectively in the local cerebral blood flow of patients with major depression (MD).

PATIENTS, MATERIAL, METHODS

The present research is semi-experimental to pre- and post-test with a control group. Three groups were formed, and this number was incorporated in each group: 12 patients were chosen randomly; the first group of depressed patients benefited from the combination of pharmacotherapy and sessions of cognitive group therapy; the second group used a combination of pharmacotherapy and sessions of happiness training; and a third group used only pharmacotherapy. We compared cognitive-behavioural therapy and happiness training efficacy with only pharmacotherapy in MD patients. We performed brain perfusion SPECT in each group, before and after each trial.

RESULTS

The study was conducted on 36 patients with MD (32 women and 4 men; mean age: 41.22 ± 9.08; range: 27-65 years). There were significant differences regarding the two trial effects into two experimental groups (p < 0/001) before and after trials, while such differences were not significant in the control group (p > 0.05). In addition, there was significant difference among the regional cerebral blood flow in the frontal and prefrontal regions into two experimental groups before and after trials (p < 0/001), while such differences were not significant in the control group (p > 0.05).

CONCLUSION

This study demonstrated decreased cerebral perfusion in the frontal regions in MD patients, which increased following cognitive group therapy and happiness training. Because of its availability, low costs, easy performance, and the objective semi-quantitative information supplied, brain perfusion SPECT scanning might be useful to assess the diagnosis and therapy efficacy. Further exploration is needed to validate its clinical role.

Neurovascular unit dysfunction with blood-brain barrier hyperpermeability contributes to major depressive disorder: a review of clinical and experimental evidence

About one-third of people with major depressive disorder (MDD) fail at least two antidepressant drug trials at 1 year. Together with clinical and experimental evidence indicating that the pathophysiology of MDD is multifactorial, this observation underscores the importance of elucidating mechanisms beyond monoaminergic dysregulation that can contribute to the genesis and persistence of MDD. Oxidative stress and neuroinflammation are mechanistically linked to the presence of neurovascular dysfunction with blood-brain barrier (BBB) hyperpermeability in selected neurological disorders, such as stroke, epilepsy, multiple sclerosis, traumatic brain injury, and Alzheimer’s disease. In contrast to other major psychiatric disorders, MDD is frequently comorbid with such neurological disorders and constitutes an independent risk factor for morbidity and mortality in disorders characterized by vascular endothelial dysfunction (cardiovascular disease and diabetes mellitus). Oxidative stress and neuroinflammation are implicated in the neurobiology of MDD. More recent evidence links neurovascular dysfunction with BBB hyperpermeability to MDD without neurological comorbidity. We review this emerging literature and present a theoretical integration between these abnormalities to those involving oxidative stress and neuroinflammation in MDD. We discuss our hypothesis that alterations in endothelial nitric oxide levels and endothelial nitric oxide synthase uncoupling are central mechanistic links in this regard. Understanding the contribution of neurovascular dysfunction with BBB hyperpermeability to the pathophysiology of MDD may help to identify novel therapeutic and preventative approaches.

Altered cerebral perfusion in executive, affective, and motor networks during adolescent depression

OBJECTIVE

Although substantial literature has reported regional cerebral blood flow (rCBF) abnormalities in adults with depression, these studies commonly necessitated the injection of radioisotopes into subjects. The recent development of arterial spin labeling (ASL), however, allows noninvasive measurements of rCBF. Currently, no published ASL studies have examined cerebral perfusion in adolescents with depression. Thus, the aim of the present study was to examine baseline cerebral perfusion in adolescent depression using a newly developed ASL technique: pseudocontinuous arterial spin labeling (PCASL).

METHOD

A total of 25 medication-naive adolescents (13-17 years of age) diagnosed with major depressive disorder (MDD) and 26 well-matched control subjects underwent functional magnetic resonance imaging. Baseline rCBF was measured via a novel PCASL method that optimizes tagging efficiency.

RESULTS

Voxel-based whole brain analyses revealed significant frontal, limbic, paralimbic, and cingulate hypoperfusion in the group with depression (p < .05, corrected). Hyperperfusion was also observed within the subcallosal cingulate, putamen, and fusiform gyrus (p < .05, corrected). Similarly, region-of-interest analyses revealed amygdalar and insular hypoperfusion in the group with depression, as well as hyperperfusion in the putamen and superior insula (p < .05, corrected).

CONCLUSIONS

Adolescents with depression and healthy adolescents appear to differ on rCBF in executive, affective, and motor networks. Dysfunction in these regions may contribute to the cognitive, emotional, and psychomotor symptoms commonly present in adolescent depression. These findings point to possible biomarkers for adolescent depression that could inform early interventions and treatments, and establishes a methodology for using PCASL to noninvasively measure rCBF in clinical and healthy adolescent populations.

The value of ethyl cysteinate dimer single photon emission computed tomography in predicting antidepressant treatment response in patients with major depression

OBJECTIVE

The purpose of this study is to examine whether the reversal of compromised regional cerebral blood flow (rCBF) in older patients with major depressive disorder (MDD) is dependent on specific parameters of selective serotonin reuptake inhibitor (SSRI) treatment and to examine the efficacy of such treatment.

METHODS

Forty-five patients with moderate MDD were studied following 8 weeks of treatment with SSRIs. Twelve patients displayed a positive response to SSRIs, whereas 33 patients did not respond to SSRI treatment. A comparison group of 30 healthy volunteers was also studied. The age of all participants was greater than 50 years. Age, gender, and the Hamilton Rating Scale for Depression scores were examined. The rCBF was assessed using 99mTc-ethyl cysteinate dimer single photon emission computed tomography after SSRI treatment.

RESULTS

The rCBF levels in the right middle frontal cortex in non-responsive MDD patients were lower compared with responsive MDD patients. Compared with healthy controls, non-responders had significantly lower rCBF levels in the bilateral middle frontal cortex and insula and had significantly higher rCBF levels in the bilateral inferior frontal cortex and left middle temporal cortex. Compared with healthy controls, responders had significantly higher rCBF levels in the left inferior frontal, middle temporal, precentral, and fusiform gyrus. We found no changes in single photon emission computed tomography between pre-treatment and post-treatment stages for the responders to SSRI treatment.

CONCLUSION

Hypoperfusion in older, non-responsive MDD patients was primarily localized in the middle frontal cortex. It is possible that the responders to SSRI treatment at baseline already displayed higher rCBF values in the frontal regions.

Longitudinal MRI study of cortical thickness, perfusion, and metabolite levels in major depressive disorder

OBJECTIVE

To determine whether patients with major depressive disorder (MDD) display morphologic, functional, and metabolic brain abnormalities in limbic-cortical regions at a baseline magnetic resonance (MR) scan and whether these changes are normalized in MDD patients in remission at a follow-up scan.

METHOD

A longitudinal 3.0-Tesla (T) magnetic resonance imaging (MRI) study was carried out with cortical thickness measurements with a surface-based approach, perfusion measurements with three-dimensional (3D) pseudo-continuous arterial spin labeling (pCASL), and spectroscopy (1H-MRS) measurements in the anterior cingulate cortex (ACC) with water as an internal reference adjusted for cerebrospinal fluid content. We examined 23 MDD patients and 26 healthy controls. MDD patients underwent a baseline MRI at inclusion and were invited to a follow-up scan when they were in remission or after a 6-month follow-up period.

RESULTS

Major findings were a significantly thinner posterior cingulate cortex in non-remitters than in remitters, a significant decrease in perfusion in the frontal lobes and the ACC in non-remitters compared with healthy controls at baseline and significantly reduced N-acetylaspartate, myo-inositol, and glutamate levels in MDD patients compared with healthy controls at baseline.

CONCLUSION

Using novel MRI techniques, we have found abnormalities in cerebral regions related to cortical-limbic pathways in MDD patients.

A pattern of cerebral perfusion anomalies between major depressive disorder and Hashimoto thyroiditis

BACKGROUND

This study aims to evaluate relationship between three different clinical conditions: Major Depressive Disorders (MDD), Hashimoto Thyroiditis (HT) and reduction in regional Cerebral Blood Flow (rCBF) in order to explore the possibility that patients with HT and MDD have specific pattern(s) of cerebral perfusion.

DESIGN

Analysis of data derived from two separate data banks.

SAMPLE

54 subjects, 32 with HT (29 women, mean age 38.8 ± 13.9); 22 without HT (19 women, mean age 36.5 ± 12.25).

ASSESSMENT

Psychiatric diagnosis was carried out by Simplified Composite International Diagnostic Interview (CIDIS) using DSM-IV categories; cerebral perfusion was measured by (99 m)Tc-ECD SPECT. Statistical analysis was done through logistic regression.

RESULTS

MDD appears to be associated with left frontal hypoperfusion, left temporal hypoperfusion, diffuse hypoperfusion and parietal perfusion asymmetry. A statistically significant association between parietal perfusion asymmetry and MDD was found only in the HT group.

CONCLUSION

In HT, MDD is characterized by a parietal flow asymmetry. However, the specificity of rCBF in MDD with HT should be confirmed in a control sample with consideration for other health conditions. Moreover, this should be investigated with a longitudinally designed study in order to determine a possible pathogenic cause. Future studies with a much larger sample size should clarify whether a particular perfusion pattern is associated with a specific course or symptom cluster of MDD.

fMRI activation in the amygdala and the orbitofrontal cortex in unmedicated subjects with major depressive disorder

Although amygdala and frontal lobe functional abnormalities have been reported in patients with mood disorders, the literature regarding major depressive disorder (MDD) is inconsistent. Likely confounds include heterogeneity of patient samples, medication status, and analytic approach. This study evaluated the amygdala and frontal lobe activation in unmedicated MDD patients. Fifteen MDD patients and 15 matched healthy controls were scanned using fMRI during the performance of an emotional face task known to robustly activate the amygdala and prefrontal cortex (PFC). Whole-brain and region of interest analyses were performed, and correlations between clinical features and activation were examined. Significant amygdala and lateral PFC activation were seen within patient and control groups. In a between-group comparison, patients showed significantly reduced activation in the insula, temporal and occipital cortices. In MDD, the presence of anxiety symptoms was associated with decreased orbitofrontal activation. We found robust activation in both the MDD and control groups in fronto-limbic regions with no significant between-group differences using either analytic approach. The current study replicates previous research on unmedicated subjects showing no significant differences in amygdala function in depressed vs. control subjects with respect to simple tasks involving emotion observation.

Cerebral perfusion after a 2-year remission in major depression

Although patients suffering from major depression respond to antidepressant treatment within several weeks, full reinstatement of premorbid capabilities requires much longer. Nevertheless, most research in major depression seeking the pathophysiological correlates of remission has focused upon the acute post-treatment period. Brain imaging research offers no exception. We have recently shown that cerebral perfusion in depressed patients responding to 6-wk antidepressant medication increases in parieto/cerebellar regions and becomes similar to that of healthy control subjects. We now present technetium-99m hexamethylpropylene amine oxime single-photon emission computed tomography (99mTc-HMPAO SPECT) data collected from 11 of these patients 2 years in remission. Images were analysed using Statistical Parametric Mapping. After 2 years, perfusion normalization found immediately after treatment was maintained, with further increases in frontal and decreases in parieto/cerebellar regions. These findings suggest that perfusion increases in parieto/cerebellar regions may be involved in acute response to treatment whereas increases in frontal regions may be related to its consolidation.

Reduced frontal perfusion in depressed postmenopausal women: a SPECT study with WCST

OBJECTIVES

To investigate frontal cerebral blood flow (CBF) in depressed postmenopausal women and its relation to cognitive function and the severity of depressive symptoms.

METHODS

Regional CBF of 20 unmedicated depressed postmenopausal women was measured using Tc-99m HMPAO SPECT, both at rest and during frontal activation using the Wisconsin card sorting test (WCST). Frontal CBF was semi-quantified by comparing the radioactivity in the prefrontal region to the cerebellum (F/C ratio). We measured the severity of the symptoms of depression using the hospital anxiety and depression scale (HADS) and cognitive function using the mini-mental status examination (MMSE).

RESULTS

At rest, there was no difference in frontal CBF between patients with moderate or severe (HADS> or =11) and patients with mild depressive symptoms (HADS<11). During the WCST, however, the HADS> or =11 group did not score as well as the HADS<11 group (P=0.03). The changes in F/C ratios were inversely correlated with HADS scores (r=-0.43, P=0.05) and positively correlated with MMSE scores (r=0.58, P=0.004). After adjusting for age, F/C ratios were significantly correlated with MMSE (P=0.002), but not with HADS scores.

CONCLUSIONS

Frontal CBF did not increase in postmenopausal women with moderate/severe symptoms of depression during the WCST activation task, and reduced frontal CBF was related to the impairment of cognitive function. The combination of the functional activation test and SPECT imaging powerfully revealed this functional disease, which remains undetectable using more common baseline measurements.