Increased prevalence of white matter hyperintensities in patients with panic disorder

Spatial patterns of white matter hyperintensities: a systematic review

Background

White matter hyperintensities are an important marker of cerebral small vessel disease. This disease burden is commonly described as hyperintense areas in the cerebral white matter, as seen on T2-weighted fluid attenuated inversion recovery magnetic resonance imaging data. Studies have demonstrated associations with various cognitive impairments, neurological diseases, and neuropathologies, as well as clinical and risk factors, such as age, sex, and hypertension. Due to their heterogeneous appearance in location and size, studies have started to investigate spatial distributions and patterns, beyond summarizing this cerebrovascular disease burden in a single metric-its volume. Here, we review the evidence of association of white matter hyperintensity spatial patterns with its risk factors and clinical diagnoses.

Design/methods

We performed a systematic review in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) Statement. We used the standards for reporting vascular changes on neuroimaging criteria to construct a search string for literature search on PubMed. Studies written in English from the earliest records available until January 31st, 2023, were eligible for inclusion if they reported on spatial patterns of white matter hyperintensities of presumed vascular origin.

Results

A total of 380 studies were identified by the initial literature search, of which 41 studies satisfied the inclusion criteria. These studies included cohorts based on mild cognitive impairment (15/41), Alzheimer's disease (14/41), Dementia (5/41), Parkinson's disease (3/41), and subjective cognitive decline (2/41). Additionally, 6 of 41 studies investigated cognitively normal, older cohorts, two of which were population-based, or other clinical findings such as acute ischemic stroke or reduced cardiac output. Cohorts ranged from 32 to 882 patients/participants [median cohort size 191.5 and 51.6% female (range: 17.9-81.3%)]. The studies included in this review have identified spatial heterogeneity of WMHs with various impairments, diseases, and pathologies as well as with sex and (cerebro)vascular risk factors.

Conclusion

The results show that studying white matter hyperintensities on a more granular level might give a deeper understanding of the underlying neuropathology and their effects. This motivates further studies examining the spatial patterns of white matter hyperintensities.

Biomarkers in Panic Disorder

Background:

Panic disorder (PD) is a kind of anxiety disorder that impacts the life quality and functional perspectives in patients. However, the pathophysiological study of PD seems still inadequate and many unresolved issues need to be clarified.

Objectives:

In this review article of biomarkers in PD, the investigator will focus on the findings of magnetic resonance imaging (MRI) of the brain in the pathophysiology study. The MRI biomarkers would be divided into several categories, on the basis of structural and functional perspectives.

Methods:

The structural category would include the gray matter and white matter tract studies. The functional category would consist of functional MRI (fMRI), resting-state fMRI (Rs-fMRI), and magnetic resonance spectroscopy (MRS). The PD biomarkers revealed by the above methodologies would be discussed in this article.

Results:

For the gray matter perspectives, the PD patients would have alterations in the volumes of fear network structures, such as the amygdala, parahippocampal gyrus, thalamus, anterior cingulate cortex, insula, and frontal regions. For the white matter tract studies, the PD patients seemed to have alterations in the fasciculus linking the fear network regions, such as the anterior thalamic radiation, uncinate fasciculus, fronto-occipital fasciculus, and superior longitudinal fasciculus. For the fMRI studies in PD, the significant results also focused on the fear network regions, such as the amygdala, hippocampus, thalamus, insula, and frontal regions. For the Rs-fMRI studies, PD patients seemed to have alterations in the regions of the default mode network and fear network model. At last, the MRS results showed alterations in neuron metabolites of the hippocampus, amygdala, occipital cortex, and frontal regions.

Conclusion:

The MRI biomarkers in PD might be compatible with the extended fear network model hypothesis in PD, which included the amygdala, hippocampus, thalamus, insula, frontal regions, and sensory-related cortex.

The impact of periventricular white matter lesions in patients with bipolar disorder type I

INTRODUCTION

White matter hyperintensities (WMHs) are one the most common neuroimaging findings in patients with bipolar disorder (BD). It has been suggested that WMHs are associated with impaired insight in schizophrenia and schizoaffective patients; however, the relationship between insight and WMHs in BD type I has not been directly investigated.

METHODS

Patients with BD-I (148) were recruited and underwent brain magnetic resonance imaging (MRI). Affective symptoms were assessed using Young Mania Rating Scale (YMRS) and Hamilton Depression Rating Scale (HDRS17); the presence of impaired insight was based on the corresponding items of YMRS and HDRS17.

RESULTS

Multiple punctate periventricular WMHs (PWMHs) and deep WMHs (DWMHs) were observed in 49.3% and 39.9% of the cases, respectively. Subjects with lower insight for mania had significantly more PWMHs (54.6% vs 22.2%; p < 0.05) when compared to BD-I patients with higher insight for mania. The presence of PWMHs was independently associated with lower insight for mania: patients who denied illness according to the YMRS were 4 times more likely to have PWMHs (95% CI: 1.21/13.42) than other patients.

CONCLUSIONS

Impaired insight in BD-I is associated with periventricular WMHs. The early identification of BD-I subjects with PWMHs and impaired insight may be crucial for clinicians.

Cerebral White Matter Lesions and Affective Episodes Correlate in Male Individuals with Bipolar Disorder

Background

Cerebral white matter lesions (WML) have been found in normal aging, vascular disease and several neuropsychiatric conditions. Correlations of WML with clinical parameters in BD have been described, but not with the number of affective episodes, illness duration, age of onset and Body Mass Index in a well characterized group of euthymic bipolar adults. Herein, we aimed to evaluate the associations between bipolar course of illness parameters and WML measured with volumetric analysis.

Methods

In a cross-sectional study 100 euthymic individuals with BD as well as 54 healthy controls (HC) were enrolled to undergo brain magnetic resonance imaging using 3T including a FLAIR sequence for volumetric assessment of WML-load using FSL-software. Additionally, clinical characteristics and psychometric measures including Structured Clinical Interview according to DSM-IV, Hamilton-Depression, Young Mania Rating Scale and Beck’s Depression Inventory were evaluated.

Results

Individuals with BD had significantly more (F = 3.968, p < .05) WML (Mdn = 3710mm3; IQR = 2961mm3) than HC (Mdn = 2185mm3; IQR = 1665mm3). BD men (Mdn = 4095mm3; IQR = 3295mm3) and BD women (Mdn = 3032mm3; IQR = 2816mm3) did not significantly differ as to the WML-load or the number and type of risk factors for WML. However, in men only, the number of manic/hypomanic episodes (r = 0.72; p < .001) as well as depressive episodes (r = 0.51; p < .001) correlated positively with WML-load.

Conclusions

WML-load strongly correlated with the number of manic episodes in male BD patients, suggesting that men might be more vulnerable to mania in the context of cerebral white matter changes.

From neural to genetic substrates of panic disorder: Insights from human and mouse studies

Fear is an ancestral emotion, an intrinsic defensive response present in every organism. Although fear is an evolutionarily advantageous emotion, under certain pathologies such as panic disorder it might become exaggerated and non-adaptive. Clinical and preclinical work pinpoints that changes in cognitive processes, such as perception and interpretation of environmental stimuli that rely on brain regions responsible for high-level function, are essential for the development of fear-related disorders. This review focuses on the involvement of cognitive function to fear circuitry disorders. Moreover, we address how animal models are contributing to understand the involvement of human candidate genes to pathological fear and helping achieve progress in this field. Multidisciplinary approaches that integrate human genetic findings with state of the art genetic mouse models will allow to elucidate the mechanisms underlying pathology and to develop new strategies for therapeutic targeting.

Altered cortical gyrification patterns in panic disorder: deficits and potential compensation

Abnormal gyrification patterns may reflect aberrant cortical connectivity during an early period of brain maturation. We here investigated anatomical distribution of cortical gyrification deficits underlying panic disorder and the relationships of these potential neurodevelopmental markers with panic symptom severity. High-resolution three-dimensional T1-weighted structural images were obtained from 23 patients with panic disorder and 33 matched healthy individuals. Local gyrification indices were measured in each genetically-based parcellated cortical subregion and regional gyrification patterns were compared between groups. Cortical areas in which gyrification patterns were associated with panic symptom severity were also determined. Significant reductions in cortical gyrification were observed in panic patients compared with healthy individuals, which were mainly distributed in the lateral brain extending from the fronto-parietal to the temporal areas. In contrast, hyper-gyrification in the posteromedial cortical regions which exert interconnecting roles in the default mode network, was associated with less severe panic symptoms. Post-hoc analysis for the inter-regional covariance of local gyrification indices revealed that interconnections of the posteromedial cortical regions with other cortical areas which belong to the default mode network were reduced in panic patients with severe symptoms relative to either less severe patients or healthy individuals. Our findings suggest not only substantial perturbation in cortical gyrification patterns in panic disorder but also potential contribution of integrated cortical folding pattern of the default mode network to alleviated panic severity.

Improvements in white matter micro-structural integrity of right uncinate fasciculus and left fronto-occipital fasciculus of remitted first-episode medication-naïve panic disorder patients

OBJECTIVE

We designed this study to investigate neural correlates of white matter micro-structural integrity of remitted patients with first-episode, medication-naïve and very late-onset panic disorder.

METHOD

Twenty-one remitted patients with panic disorder completed treatment course with treatment of escitalopram (dose range around 10-15 mg/d). Twenty-one healthy controls were also enrolled into this study. Patients and controls all received 3-Tesla magnetic resonance imaging diffusion tensor imaging scanning at baseline and 6th week. We utilized FDT (FMRIB's Diffusion Toolbox v2.0) function of FSL (FMRIB Software Library) to calculate fractional anisotropy (FA). We compared FA values of patients and controls at baseline and 6th week to estimate the changes of FA of remitted patient group and inter-scan bias of controls. FA outputs of remitted patients and controls were compared by independent t test.

RESULTS

We found increased FA in some regions of right uncinate fasciculus and left fronoto-occipital fasciculus after remission in patient group (corrected p<0.05). Reduced FA of other regions of right uncinate fasciculus was still observed in remitted patients when they were compared to the control group.

CONCLUSION

Subtle changes of white matter micro-structural integrity after remission might represent neural correlates of treatment effects for first-episode, medication-naïve and very late-onset panic disorder.

The effects of the catechol-O-methyltransferase val158met polymorphism on white matter connectivity in patients with panic disorder

BACKGROUND

The catechol-O-methyltransferase (COMT) gene val158met polymorphism (rs4680) has been found to be associated with various psychiatric phenotypes including panic disorder. Considering the probable genetic influence of COMT on the pathogenesis of panic disorder and white matter connectivity, the present study investigated white matter connectivity using diffusion tensor imaging in relation to the COMT genotype in panic disorder.

METHODS

Twenty-six patients with panic disorder and twenty-six age- and gender-matched healthy controls participated in this study. Brain magnetic resonance scans and genotype analysis for COMT rs4680 were conducted. Panic Disorder Severity Scale, Albany Panic and Phobia Questionnaire, and Anxiety Sensitivity Inventory-Revised were assessed. Tract-based spatial statistics (TBSS) were used for image analysis.

RESULTS

There was no significant difference in white matter analysis between panic disorder and healthy controls. However, TBSS analysis showed increased fractional anisotropy (FA) in posterior thalamic radiation, posterior and superior corona radiata, superior longitudinal fasciculus, and sagittal stratum, all located in the right hemisphere in COMT AA/AG genotype group compared to GG genotype in panic disorder. Voxelwise correlational analysis revealed the symptom severity scores are correlated with the FA in white matter tracts that previously showed significant group differences between AA/AG and GG genotypes in COMT AA/AG genotype group, while no significant correlation was found in GG genotype group.

LIMITATIONS

The sample size in each group was small, hence, further studies with larger numbers of patients are needed to confirm our findings.

CONCLUSIONS

These data suggested that COMT rs4680 could affect the white matter connectivity in panic disorder.

Fronto-occipital fasciculus, corpus callosum and superior longitudinal fasciculus tract alterations of first-episode, medication-naïve and late-onset panic disorder patients

OBJECTIVE

Because of limited knowledge about white matter (WM) tract in panic disorder, we designed this study to investigate alterations of WM tracts in first-episode medication-naïve panic disorder patients.

METHODS

Thirty patients and 21 normal controls were enrolled into our study. They all received acquisitions of diffusion tensor imaging (DTI) in 30 directions. DTI images of patients and controls were preprocessed and analyzed to estimate differences of WM microintegrity between patients and controls. We obtained fractional anisotropy (FA) values from the DTI images. FA outputs of patients and controls were compared by non-parametric permutation-based method with global brain volume, age, gender and duration of illness as covariates. Correlations between severity of panic symptoms and FA values were also estimated.

RESULTS

First-episode, medication-naïve and late-onset panic disorder patients had altered integrity in WM tracts of right inferior fronto-occipital fasculi, left body of corpus callosum and left superior longitudinal fasciculus when compared to controls (corrected p<0.05). Negative correlations between PD symptoms and FA values were observed in corpus callosum of patient group (corrected p<0.05).

CONCLUSIONS

WM tract alterations might represent structural pathophysiology in WM of first-episode, medication-naïve and late-onset panic disorder patients.

T2 hyperintensity of medial lemniscus: higher threshold application to ROI measurements is more accurate in predicting small vessel disease

BACKGROUND

Medial lemniscus T2 hyperintensity (MLH) has been recently demonstrated as potential imaging marker for small vessel disease (SVD). Our purpose in this study is to improve accuracy of regions of interest (ROI) analysis for this imaging finding.

METHODS AND METHODS

Two neuroradiologists retrospectively reviewed 103 consecutive outpatient brain MRI. Medial lemniscus signal in dorsal pons was evaluated; visually on FLAIR and with ROI on T2. Original MRI interpretations were divided into three categories; SVD, multiple sclerosis (MS), and nonspecific WM changes (non).

RESULTS

Thirty-seven patients had SVD, 14 patients had MS, 52 had Non. Visual MLH was seen exclusively with SVD and was generally bilateral. Patients with visual MLH belonged to advanced SVD by imaging and clinical parameters. Compared to visual data, ROI analyses of MLH has been known to be compounded by false positives and negatives at low threshold (20% of adjacent to normal brainstem signal). With application of higher ROI threshold (25%), false positives were eliminated but false negatives increased. ROI analyses of MLH by experienced neuroradiologist were more reliable.

CONCLUSION

MLH seen on high threshold ROI analysis is a reliable radiologic marker in predicting SVD. ROI analysis of MLH should be performed by an experienced neuroradiologist.

T2 hyperintensity of medial lemniscus is an indicator of small-vessel disease

OBJECTIVE

Small-vessel disease is a common MRI finding that can be difficult to differentiate from other white matter (WM) diseases because of the lack of a specific pattern of brain involvement. The purpose of our study was to evaluate medial lemniscus hyperintensity seen on FLAIR images as an imaging marker for small-vessel disease.

MATERIALS AND METHODS

Two blinded neuroradiologists retrospectively reviewed 103 consecutive outpatient brain MRI studies. Medial lemniscus signal in the dorsal pons was evaluated visually on FLAIR images and after placing regions of interest (ROIs) on T2-weighted images. On the basis of the original interpretations, scans were divided into three categories: small-vessel disease, multiple sclerosis (MS), and normal or nonspecific WM changes. Cardiovascular risk factors were recorded. Analysis of variance and Fisher exact tests were used to determine group differences, and kappa statistics was used to determine interrater agreement.

RESULTS

Thirty-seven patients had small-vessel disease, 14 patients had MS, and 52 had nonspecific WM changes. Medial lemniscus hyperintensity was seen in about 20% of patients with small-vessel disease and was generally bilateral. Although ROI analyses identified a slightly higher number of patients with medial lemniscus signal > 20% of adjacent to normal-appearing brainstem, interrater reliability was moderate, and there were false-positive and false-negative cases in comparison with visual data. When small-vessel disease patients were further subdivided into mild or advanced subgroups, medial lemniscus hyperintensity was selectively seen in advanced small-vessel disease. Patients with medial lemniscus hyperintensity were older (p < 0.001) and had higher prevalence of diabetes (p = 0.03), hypertension (p = 0.009), and hypercholesterolemia (p = 0.03).

CONCLUSION

Medial lemniscus hyperintensity seen on FLAIR images is a reliable radiologic marker of advanced small-vessel disease.

An evidence-based causal model of panic disorder

Recently, Fava and Morton (2009) described what they termed a 'causal model' of panic disorder (Causal modeling of panic disorder theories, Clinical Psychology Review, 29, 623-637). We examined several critical tenets of this proposed model, and offer significant revisions. Our revised causal model includes elements that have received empirical support, and exclude those with known limitations in explaining the etiology and treatment of panic disorder. Chief among these revisions are (1) an increased emphasis on anxiety sensitivity, (2) elimination of the more general psychodynamic conceptualization in favor of empirically supported findings regarding early attachment, and (3) placing biological and psychophysiological reactions as outcomes of false alarm threat, rather than causal mechanisms of panic.