Search

Patients with obstructive sleep apnea (OSA) show brain injury in sites responsible for autonomic, cognitive, and respiratory functions. Brain changes in OSA may vary with disease severity as assessed by the apnea-hypopnea index (AHI), which does not provide information about the apnea depth and length in contrast to oxygen desaturation. Although significant associations with brain injury and AHI are known in OSA, it is unclear whether AHI or the extent of oxygen desaturations better correlate with brain damage. We evaluated associations between brain changes, AHI, and oxygen desaturation using diffusion tensor imaging-based measures.We acquired diffusion tensor imaging data from 19 patients with OSA using a 3.0-Tesla MRI scanner and calculated, normalized, and smoothed mean, axial, and radial diffusivity maps that were used for correlations between brain changes, oxygen desaturation, and AHI values.Positive correlations with extent of injury (mean, axial, and radial diffusivity values) and AHI appeared in the frontal areas, cingulate and insula, amygdala, hippocampus, and basal pons, and negative associations emerged in the putamen, internal-capsule, globus-pallidus, and cerebellar cortices. Regional diffusivity values and oxygen desaturation showed positive correlations in the cingulate, frontal, putamen, and cerebellar sites, and negative relationships in several areas, including the occipital cortex.Patients with OSA show negative and positive correlations, indicated by increased and decreased diffusivity values, resulting from chronic and acute changes in those areas. The extent of injury in OSA partially depends on the extent of AHI and oxygen desaturation, with the effects representing continued development from acute to chronic processes.Sahib A, Roy B, Kang D, Aysola RS, Wen E, Kumar R. Relationships between brain tissue damage, oxygen desaturation, and disease severity in obstructive sleep apnea evaluated by diffusion tensor imaging.

Youth impacted by homelessness experience diminished cognition due to a variety of reasons including mental health symptoms, alcohol and substance use, and adverse childhood experiences. However, the status of specific brain regions which could impact important cognitive functions in homeless youth remains unclear. In this pilot comparative and correlational study, a series of demographic, psychological, cognitive assessments, and brain magnetic resonance imaging were performed in 10 male youth experiencing homelessness and 9 age-matched healthy male controls (age range: 18–25 years). Participants experiencing homelessness had significantly decreased regional brain gray matter tissue in comparison to the controls. Moreover, there were strong inverse correlations between the brain regions classically associated with executive decision-making (prefrontal cortices), depression (insular lobes), and conflict resolution (anterior cingulate), and the level of the symptoms detected by their questionnaires.

Adolescents with single ventricle heart disease (SVHD) exhibit mood and cognitive deficits, which may result from injury to the basal ganglia structures, including the caudate nuclei. However, the integrity of the caudate in SVHD adolescents is unclear. Our aim was to examine the global and regional caudate volumes, and evaluate the relationships between caudate volumes and cognitive and mood scores in SVHD and healthy adolescents. We acquired two high-resolution T1-weighted images from 23 SVHD and 37 controls using a 3.0-Tesla MRI scanner, as well as assessed mood (Patient Health Questionnaire-9 [PHQ-9]; Beck Anxiety Inventory [BAI]) and cognition (Montreal Cognitive Assessment [MoCA]; Wide Range Assessment of Memory and Learning–2; General Memory Index [GMI]) functions. Both left and right caudate nuclei were outlined, which were then used to calculate and compare volumes between groups using ANCOVA (covariates: age, gender, and head-size), as well as perform 3D surface morphometry. Partial correlations (covariates: age, gender, and head-size) were used to examine associations between caudate volumes, cognition, and mood scores in SVHD and controls. SVHD subjects showed significantly higher PHQ-9 and BAI scores, indicating more depressive and anxiety symptoms, as well as reduced GMI scores, suggesting impaired cognition, compared to controls. SVHD patients showed significantly reduced caudate volumes (left, 3,198.8 ± 490.1 vs. 3,605.0 ± 480.4 mm(3), p < 0.004; right, 3,162.1 ± 475.4 vs. 3,504.8 ± 465.9 mm(3), p < 0.011) over controls, and changes were localized in the rostral, mid-dorsolateral, and caudal areas. Significant negative correlations emerged between caudate volumes with PHQ-9 and BAI scores and positive correlations with GMI and MoCA scores in SVHD and controls. SVHD adolescents show significantly reduced caudate volumes, especially in sites that have projections to regulate mood and cognition, which may result from developmental and/or hypoxia-/ischemia-induced processes.

Background Cystic fibrosis (CF) patients present with a variety of symptoms, including mood and cognition deficits, in addition to classical respiratory, and autonomic issues. This suggests that brain injury, which can be examined with non-invasive magnetic resonance imaging (MRI), is a manifestation of this condition. However, brain tissue integrity in sites that regulate cognitive, autonomic, respiratory, and mood functions in CF patients is unclear. Our aim was to assess regional brain changes using high-resolution T1-weighted images based gray matter (GM) density and T2-relaxometry procedures in CF over control subjects. Methods We acquired high-resolution T1-weighted images and proton-density (PD) and T2-weighted images from 5 CF and 15 control subjects using a 3.0-Tesla MRI. High-resolution T1-weighted images were partitioned to GM-tissue type, normalized to a common space, and smoothed. Using PD- and T2-weighted images, whole-brain T2-relaxation maps were calculated, normalized, and smoothed. The smoothed GM-density and T2-relaxation maps were compared voxel-by-voxel between groups using analysis of covariance (covariates, age and sex; SPM12, p Results Significantly increased GM-density, indicating tissues injury, emerged in multiple brain regions, including the cerebellum, hippocampus, amygdala, basal forebrain, insula, and frontal and prefrontal cortices. Various brain areas showed significantly reduced T2-relaxation values in CF subjects, indicating predominant acute tissue changes, in the cerebellum, cerebellar tonsil, prefrontal and frontal cortices, insula, and corpus callosum. Conclusions Cystic fibrosis subjects show predominant acute tissue changes in areas that control mood, cognition, respiratory, and autonomic functions and suggests that tissue changes may contribute to symptoms resulting from ongoing hypoxia accompanying the condition.

Patients with epilepsy, who later succumb to sudden unexpected death, show altered brain tissue volumes in selected regions. It is unclear whether the alterations in brain tissue volume represent changes in neurons or glial properties, since volumetric procedures have limited sensitivity to assess the source of volume changes (e.g., neuronal loss or glial cell swelling). We assessed a measure, entropy, which can determine tissue homogeneity by evaluating tissue randomness, and thus, shows tissue integrity; the measure is easily calculated from T1-weighted images. T1-weighted images were collected with a 3.0-Tesla MRI from 53 patients with tonic-clonic (TC) seizures and 53 healthy controls; images were bias-corrected, entropy maps calculated, normalized to a common space, smoothed, and compared between groups (TC patients and controls using ANCOVA; covariates, age and sex; SPM12, family-wise error correction for multiple comparisons, p

BACKGROUND Inadequate self-care is linked to poor health outcomes in heart failure (HF). Self-care depends on decision-making abilities, but links between self-care and brain injury to executive decision-making regulatory areas (prefrontal cortices) are unclear. OBJECTIVE We investigated the relationships between HF self-care and status of prefrontal cortices. METHODS Magnetic resonance imaging-based diffusion tensor imaging was performed in 21 patients with HF (age, 53.8 ± 7.9 years; 15 men; left ventricular ejection fraction, 25.1% ± 6.1%), and self-care and executive function were measured with the Self-care of Heart Failure Index (SCHFI) and Trail Making Test B. Using diffusion tensor imaging data, mean diffusivity (MD) maps were calculated and region-of-interest analyses were performed on the left and right prefrontal brain areas. Statistical analyses consisted of partial correlations (covariates, age, and gender). RESULTS The mean ± SD SCHFI scores were 70.78 ± 11.37 for maintenance, 70 ± 17.32 for management, and 74.91 ± 15.76 for confidence. The mean ± SD Trail Making Test B score was 90.2 ± 73.3 seconds. The mean ± SD MD values (higher values indicate tissue injury) of the left and right prefrontal cortices were 1.46 ± 0.16 (×10 mm/s) and 1.44 ± 0.14 (×10 mm/s), respectively. Significant negative correlations emerged between prefrontal MD values and SCHFI maintenance (left/right, r = -0.64/-0.70; P < .003) and SCHFI management (r = -0.93/-0.86; P < .003). Significant positive correlations were observed between prefrontal MD values and Trail Making Test B (r = 0.71/0.74; P < .001). A nonsignificant correlation emerged between prefrontal MD values and SCHFI confidence scores. CONCLUSIONS Brain tissue integrity in executive function regulatory regions is associated with HF self-care for maintenance and management. The findings indicate that protection and brain injury repair in executive control areas may improve HF self-care.

Background: Adolescents with single ventricle heart disease (SVHD), who have undergone the Fontan procedure, show cognitive/memory deficits. Mammillary bodies are key brain sites that regulate memory; however, their integrity in SVHD is unclear. We evaluated mammillary body (MB) volumes and their associations with cognitive/memory scores in SVHD and controls. Methods: Brain MRI data were collected from 63 adolescents (25 SVHD; 38 controls) using a 3.0-Tesla MRI scanner. Cognition and memory were assessed using Montreal Cognitive Assessment (MoCA) and Wide Range Assessment of Memory and Learning 2. MB volumes were calculated and compared between groups (ANCOVA, covariates: age, sex, and total-brain-volume [TBV]). Partial correlations and linear regression were performed to examine associations between volumes and cognitive scores (covariates: age, sex, and TBV). Results: SVHD group showed significantly lower MoCA and WRAML2 scores over controls. MB volumes were significantly reduced in SVHD over controls. After controlling for age, sex, and TBV, MB volumes correlated with MoCA and delayed memory recall scores in SVHD and controls. Conclusion: Adolescents with SVHD show reduced MB volumes associated with cognitive/memory deficits. Potential mechanisms of volume losses may include developmental and/or hypoxic/ischemic-induced processes. Providers should screen for cognitive deficits and explore possible interventions to improve memory.

Background Patients with heart failure (HF) show abnormal autonomic activities, which may stem from altered functional connectivity (FC) between different brain sites. Methods and Results We evaluate insular and cerebellar FC with other brain areas, before, during, and after the Valsalva challenge, with functional magnetic resonance imaging in 35 HF and 35 control subjects. Significant insular FC emerged with striatum, thalamus, and anterior cingulate. While left and right cerebellar cortices showed significant FC with each other constituting the cerebellum network, the insula and cerebellum networks showed significant negative FC with each other at baseline, challenge, and recovery phases. The challenge induced increased FC within the insula and the cerebellum networks in both HF and controls. However, patients with HF showed more increased insular network FC, but less enhanced cerebellar FC. During the recovery phase, the negative FC between the insular network and cerebellum enhanced significantly in controls, but not in HF. Lower left ventricle ejection fraction was correlated with lower insula network FC, and impaired negative FC between cerebellum and the insula network in HF. Conclusions Increased insular FC in patients with HF might contribute to exaggerated sympathetic tone. While impaired cerebellar FC and diminished negative interactions between cerebellum and insular systems may indicate impaired parasympathetic functions in HF.

Background and purpose Patients with pulmonary arterial hypertension (PAH) frequently present with anxiety, depression, autonomic, and cognitive deterioration, which may indicate brain changes in regions that control these functions. However, the precise regional brain-injury in sites that regulate cognitive, autonomic, and mood functions in PAH remains unclear. We examined the shifts in regional gray matter (GM) volume, using high-resolution T1-weighted images, and brain tissue alterations, using T2-relaxometry procedures, in PAH compared to healthy subjects. Methods We collected two high-resolution T1-weighted series, and proton-density and T2-weighted images using a 3.0-Tesla magnetic resonance imaging scanner from 9 PAH and 19 healthy subjects. Both high-resolution T1-weighted images were realigned and averaged, partitioned to GM tissue type, normalized to a common space, and smoothed. Using proton-density and T2-weighted images, T2-relaxation maps were calculated, normalized to a common space, and smoothed. Whole-brain GM volume and T2-relaxation maps were compared between PAH and controls using analysis of covariance (covariates, age, sex, and total-brain-volume; false discover rate corrections). Results Significantly decreased GM volumes, indicating tissue injury, emerged in multiple brain regions, including the hippocampus, insula, cerebellum, parahippocampus, temporal, frontal, and occipital gyri, cingulate, amygdala, and thalamus. Higher T2-relaxation values, suggesting tissue damage, appeared in the cerebellum, hippocampus, parahippocampus, frontal, lingual, and temporal and occipital gyri, and cingulate areas in PAH compared to healthy subjects. Conclusions PAH patients showed significant GM injury and brain tissue changes in sites that regulate cognition, autonomic, and mood functions. These findings indicate a brain structural basis for functional deficits in PAH patients.

Introduction Adolescents with single ventricle congenital heart disease (SVHD) show functional deficits, particularly in memory and mood regulation. Hippocampi are key brain structures that regulate mood and memory; however, their tissue integrity in SVHD is unclear. Our study aim is to evaluate hippocampal volumes and their associations with memory, anxiety, and mood scores in adolescents with SVHD compared to healthy controls. Methods We collected brain magnetic resonance imaging data from 25 SVHD (age 15.9 ± 1.2 years; 15 male) and 38 controls (16.0 ± 1.1 years; 19 male) and assessed memory (Wide Range Assessment of Memory and Learning 2, WRAML2), anxiety (Beck Anxiety Inventory, BAI), and mood (Patient Health Questionnaire 9, PHQ‐9) functions. Both left and right hippocampi were outlined and global volumes, as well as three‐dimensional surfaces were compared between groups using ANCOVA and associations with cognitive and behavioral scores with partial correlations (covariates: age and total brain volume). Results The SVHD group showed significantly higher BAI (p = .001) and PHQ‐9 (p, Right hippocampal volume was significantly reduced in adolescents with SVHD compared to controls, localized in several sites (CA1, CA4, subiculum, and dentate gyrus), which are associated with memory deficits and trended toward significance in anxiety and mood.

Background and purpose To evaluate the performance of multiparametric MR images in differentiation of different regions of the gross tumor area and for assessment of glioma grade. Methods Forty-six glioma subjects (18 grade II, 11 grade III, and 17 grade IV) underwent a comprehensive MR and spectroscopic imaging procedure. Maps were generated by subtraction of T1-weighted images from contrast-enhanced T1-weighted images (ΔT1 map) and T1-weighted images from T2-weighted images (ΔT2 map). Regions of interest (ROIs) were positioned in normal-appearing white matter (NAWM), enhancing tumor, hyperintense T2, necrotic region, and immediate and distal peritumoral regions (IPR and DPR). Relative signal contrast was estimated as difference between mean intensities in ROIs and NAWM. Classification using support vector machines was applied to all image series to determine the efficacy of regional contrast measures for differentiation of low- and high-grade lesions and grade III and IV lesions. Results ΔT1 and ΔT2 maps offered higher contrast as compared to other parametric maps in differentiating enhancing tumor and edematous regions, respectively, and provided the highest classification accuracy for differentiating low- and high-grade tumors, of 91% and 90.4%. Choline/N-acetylaspartate maps provided significant contrast for delineating IPR and DPR. For differentiating high-grade gliomas, ΔT2 and ΔT1 maps provided a mean accuracy of 90.9% and 88.2%, which was lower than that obtained using cerebral blood volume (93.7%) and choline/creatine (93.3%) maps. Conclusion This study showed that subtraction maps provided significant contrast in differentiating several regions of the gross tumor area and are of benefit for accurate tumor grading.

Patients with Type 2 diabetes mellitus (T2DM) show cognitive and mood impairment, indicating potential for brain injury in regions that control these functions. However, brain tissue integrity in cognition, anxiety, and depression regulatory sites, and their associations with these functional deficits in T2DM subjects remain unclear. We examined gray matter (GM) changes in 34 T2DM and 88 control subjects using high-resolution T1-weighted images, collected from a 3.0-Tesla magnetic resonance imaging scanner, and assessed anxiety [Beck Anxiety Inventory], depressive symptoms [Beck Depression Inventory-II], and cognition [Montreal Cognitive Assessment]. We also investigated relationships between GM status of cognitive and mood control sites and these scores in T2DM. Significantly increased anxiety (p = 0.003) and depression (p = 0.001), and reduced cognition (p = 0.002) appeared in T2DM over controls. Decreased GM volumes appeared in several regions in T2DM patients, including the prefrontal, hippocampus, amygdala, insular, cingulate, cerebellum, caudate, basal-forebrain, and thalamus areas (p

BACKGROUND This study examined brain tissue integrity in sites that controls cognition (prefrontal cortices; PFC) and its relationships to glycemic outcomes in adults with type 2 diabetes mellitus (T2DM). METHODS We examined 28 T2DM patients (median age 57.1 years; median body mass index [BMI] 30.6 kg/m2 ;11 males) and 47 healthy controls (median age 55.0 years; median BMI 25.8 kg/m2 ; 29 males) for cognition (Montreal Cognitive Assessment [MoCA]), glycemic control (hemoglobin A1c [HbA1c]), and PFC tissue status via brain magnetic resonance imaging (MRI). High-resolution T1-weighted images were collected using a 3.0-Tesla MRI scanner, and PFC tissue changes (tissue density) were examined with voxel-based morphometry procedures. RESULTS Reduced PFC density values were observed in T2DM patients compared to controls (left, 0.41 ± 0.02 mm3 /voxel vs 0.44 ± 0.02 mm3 /voxel, P

BACKGROUND Single ventricle heart disease (SVHD) adolescents show cognitive impairments and anxiety and depressive symptoms, indicating the possibility of brain injury in regions that control these functions. However, brain tissue integrity in cognition, anxiety, and depression regulatory sites in SVHD remains unclear. We examined brain tissue changes in SVHD compared to controls using T2-relaxometry procedures, which measure free water content and show tissue injury. METHODS Proton-density and T2-weighted images, using a 3.0-Tesla MRI, as well as anxiety (Beck anxiety inventory [BAI]), depressive symptoms (patient health questionnaire-9 [PHQ-9]), and cognition (wide range assessment of memory and learning 2 [WRAML2] and Montreal cognitive assessment [MoCA]) data were collected from 20 SVHD (age: 15.8 ± 1.1 years, male/female: 11/9) and 36 controls (age: 16.0 ± 1.1 years, male/female: 19/17). Whole-brain T2-relaxation maps were calculated, normalized to a common space, smoothed, and compared between groups and sexes (analysis of covariance; covariates: age, sex; p

PURPOSE: Single ventricle heart disease (SVHD) patients show injury in brain sites that regulate autonomic, mood, and cognitive functions. However, the nature (acute or chronic changes) and extent of brain injury in SVHD are unclear. Our aim was to examine regional brain tissue damage in SVHD over controls using DTI-based mean diffusivity (MD), axial diffusivity (AD), radial diffusivity (RD), and fractional anisotropy (FA) procedures. METHODS: We collected two DTI series (3.0–Tesla MRI), mood and cognitive data from 27 SVHD and 35 control adolescents. Whole-brain MD, AD, RD, and FA maps were calculated from each series, realigned and averaged, normalized to a common space, smoothed, and compared between groups using ANCOVA (covariates, age and sex; false-discovery-rate, p

Heart failure (HF) patients show inability to regulate autonomic functions in response to autonomic challenges. The autonomic deficits may stem from brain tissue injury in central autonomic regulatory areas, resulting from ischemic and hypoxic processes accompanying the condition. However, the direct evaluation of correlations between brain structural injury and functional timing and magnitude of neural signal patterns within affected areas, which may lead to impaired autonomic outflow, is unclear. In this study, we evaluate neural responses to the Valsalva maneuver with blood oxygen level-dependent (BOLD) functional magnetic resonance imaging (fMRI) in 29 HF patients and 35 control subjects and brain structural changes using diffusion tensor imaging (DTI)-based mean diffusivity (MD) in a subsample of 19 HF and 24 control subjects. HF showed decreased neural activation in multiple autonomic and motor control areas, including cerebellum cortices, vermis, left insular, left putamen, and bilateral postcentral gyrus. Structural brain changes emerged in similar autonomic, as well as cognitive and mood regulation areas. Functional MRI responses in cerebellum and insula in HF subjects are delayed or decreased in magnitude to the challenge. The impaired functional responses of insular and cerebellar sites are correlated with the severity of tissue changes. These results indicate that the functions of insular and cerebellar regions, sites that are involved in autonomic regulation, are compromised, and that autonomic deficits in these areas have brain structural basis for impaired functions. Our study enhanced our understanding of brain structural and functional alterations underlying impaired autonomic regulations in HF subjects.

Adolescents with single ventricle heart disease (SVHD) show autonomic, mood, and cognitive deficits, indicating aberrations in brain areas that regulate these functions. However, the gray matter integrity in autonomic, mood, and cognitive control sites is unclear. We examined regional brain gray matter changes, using high-resolution T1-weighted images (3.0-Tesla magnetic resonance scanner) with voxel based morphometry procedures, as well as mood and cognitive functions in SVHD (n = 18; age, 15.7±1.1 years; male, 10) and controls (n = 31; age, 16.0±1.1 years; male, 17). High-resolution T1-weighted images were realigned, gray matter tissue type partitioned, normalized to a common space, smoothed, and compared between groups (analysis of covariance; covariates, age and gender). The mood and cognitive scores were compared between groups using independent samples t-tests. SVHD subjects showed significantly altered mood and cognitive functions over controls. Significantly reduced gray matter emerged in multiple brain areas, including the thalamus, caudate nuclei, putamen, insula, prefrontal, post-central and precentral gyrus, occipital gyrus, para-hippocampal gyrus, temporal gyrus, and cerebellar sites in SVHD over controls. SVHD subjects show compromised gray matter integrity in autonomic, mood and cognitive control sites. The findings indicate that frequent deficits found in SVHD subjects have a brain structural basis in the condition.

Introduction Vitamin B12 deficiency may cause neural tissue damage. Even in advanced stages, conventional imaging of brain usually appears normal in vitamin B12 deficient patients. The aim of this study was to assess the structural and functional changes in brain of patients with vitamin B12 deficiency before and after six weeks of vitamin B12 supplementation using diffusion tensor imaging and pseudo-continuous arterial spin labelling (PCASL). Methods MR imaging including DTI and PCASL and neuropsychological tests (NPT) were performed in 16 patients with vitamin B12 deficiency and 16 controls before and after 6 weeks of therapy. Cerebral blood flow (CBF) derived from PCASL and DTI indices was calculated in brain of patients with vitamin B12 deficiency and controls. Results Patient with vitamin B12 deficiency showed altered neuropsychological scores and altered CBF as well as fractional anisotropy (FA) values in various brain regions as compared with controls. Both CBF values and neuropsychological scores showed complete reversibility at 6 weeks post therapy. Though FA values showed significant recovery, it failed to show complete recovery. Conclusion Our results suggest that micro-structural recovery lags behind functional recovery in patients with vitamin B12 deficiency following therapy and CBF change may be used as an early predictor of complete recovery in patients with B12 deficiency.

Author(s): Song, Xiaopeng; Roy, Bhaswati; Kang, Daniel W; Aysola, Ravi S; Macey, Paul M; Woo, Mary A; Yan-Go, Frisca L; Harper, Ronald M; Kumar, Rajesh | Abstract: IntroductionBrain structural injury and metabolic deficits in the hippocampus and caudate nuclei may contribute to cognitive and emotional deficits found in obstructive sleep apnea (OSA) patients. If such contributions exist, resting-state interactions of these subcortical sites with cortical areas mediating affective symptoms and cognition should be disturbed. Our aim was to examine resting-state functional connectivity (FC) of the hippocampus and caudate to other brain areas in OSA relative to control subjects, and to relate these changes to mood and neuropsychological scores.MethodsWe acquired resting-state functional magnetic resonance imaging (fMRI) data from 70 OSA and 89 healthy controls using a 3.0-Tesla magnetic resonance imaging scanner, and assessed psychological and behavioral functions, as well as sleep issues. After standard fMRI data preprocessing, FC maps were generated for bilateral hippocampi and caudate nuclei, and compared between groups (ANCOVA; covariates, age and gender).ResultsObstructive sleep apnea subjects showed significantly higher levels of anxiety and depressive symptoms over healthy controls. In OSA subjects, the hippocampus showed disrupted FC with the thalamus, para-hippocampal gyrus, medial and superior temporal gyrus, insula, and posterior cingulate cortex. Left and right caudate nuclei showed impaired FC with the bilateral inferior frontal gyrus and right angular gyrus. In addition, altered limbic-striatal-cortical FC in OSA showed relationships with behavioral and neuropsychological variables.ConclusionsThe compromised hippocampal-cortical FC in OSA may underlie depression and anxious mood levels in OSA, while impaired caudate-cortical FC may indicate deficits in reward processing and cognition. These findings provide insights into the neural mechanisms underlying the comorbidity of mood and cognitive deficits in OSA.

Objective Obstructive sleep apnea (OSA) is accompanied by brain changes in areas that regulate autonomic, cognitive, and mood functions, which were initially examined by Gaussian-based diffusion tensor imaging measures, but can be better assessed with non-Gaussian measures. We aimed to evaluate axonal and myelin changes in OSA using axial (AK) and radial kurtosis (RK) measures. Materials and methods We acquired diffusion kurtosis imaging data from 22 OSA and 26 controls; AK and RK maps were calculated, normalized, smoothed, and compared between groups using analysis of covariance. Results Increased AK, indicating axonal changes, emerged in the insula, hippocampus, amygdala, dorsolateral pons, and cerebellar peduncles and showed more axonal injury over previously identified damage. Higher RK, showing myelin changes, appeared in the hippocampus, amygdala, temporal and frontal lobes, insula, midline pons, and cerebellar peduncles and showed more widespread myelin damage over previously identified injury. Conclusions Axial kurtosis and RK measures showed widespread changes over Gaussian-based techniques, suggesting a more sensitive nature of kurtoses to injury.

BACKGROUND AND PURPOSE: Increased glycine concentration in the brain is associated with altered metabolism in cancer and can be detected by using in vivo MR spectroscopy. This has been proposed as a marker for grade IV gliomas; however, little is known about the potential significance and frequency of in vivo glycine observation. The purpose of this study was to examine the rate of occurrence and spatial distribution of glycine observation with respect to other MR imaging parameters. MATERIALS AND METHODS: Data from volumetric whole-brain MR spectroscopic imaging of 59 subjects with glioma were analyzed with glycine included in the spectral model. The associations of the signal amplitude and spatial distributions of glycine with findings from contrast-enhanced T1, perfusion, and diffusion MR imaging were then examined. RESULTS: Glycine was detected in 24% of all studies, though with a wide range of signal amplitude and extent of the spatial distributions. While more commonly seen in grade IV tumors (42% of studies), relatively large concentrations were also detected in grade II and III gliomas. Coanalysis with other metabolites indicated a strong association with choline and that glycine was frequently seen to be overlapping with, and adjacent to, areas of high lactate concentration. Increased glycine was always associated with contrast enhancement and areas of increased cerebral blood flow, but without any clear association with other image parameters. CONCLUSIONS: Detection of increased glycine in gliomas appears to identify a subgroup of tumors and areas of increased proliferation.

Objective The aim of this study was to evaluate the role of whole-body magnetic resonance imaging (WB-MRI) in imaging of extrapulmonary tuberculosis. Methods Eighteen patients with single-site extrapulmonary tuberculosis were evaluated with contrast-enhanced dedicated MRI of the clinically symptomatic site followed by WB-MRI using contrast-enhanced 3-dimensional (3D) modified DIXON technique (m-DIXON) and diffusion-weighted WB imaging with background body signal suppression (DWIBS) sequences. Studies were read by 2 experienced radiologists, and additional lesions seen on WB-MRI were separately charted. Results Of 18 patients, 14 were found to have asymptomatic involvement of other organs on WB-MRI. In 5 patients, the information was helpful in choosing an easily accessible site for biopsy/aspiration. Postcontrast 3D m-DIXON was better in picking up brain and lymph nodal lesions, whereas DWIBS was better in detecting vertebral lesions. Conclusions Whole-body MRI may be used for assessing the asymptomatic involvement of other body organs in tuberculosis. The combination of postcontrast 3D m-DIXON and DWIBS is complementary and may provide a road map for biopsy of accessible lesions.

Accurate grading of cerebral glioma using conventional structural imaging techniques remains challenging due to the relatively poor sensitivity and specificity of these methods. The purpose of this study was to evaluate the relative sensitivity and specificity of structural magnetic resonance imaging and MR measurements of perfusion, diffusion, and whole-brain spectroscopic parameters for glioma grading. Fifty-six patients with radiologically suspected untreated glioma were studied with T1- and T2-weighted MR imaging, dynamic contrast-enhanced MR imaging, diffusion tensor imaging, and volumetric whole-brain MR spectroscopic imaging. Receiver-operating characteristic analysis was performed using the relative cerebral blood volume (rCBV), apparent diffusion coefficient, fractional anisotropy, and multiple spectroscopic parameters to determine optimum thresholds for tumor grading and to obtain the sensitivity, specificity, and positive and negative predictive values for identifying high-grade gliomas. Logistic regression was performed to analyze all the parameters together. The rCBV individually classified glioma as low and high grade with a sensitivity and specificity of 100 and 88 %, respectively, based on a threshold value of 3.34. On combining all parameters under consideration, the classification was achieved with 2 % error and sensitivity and specificity of 100 and 96 %, respectively. Individually, CBV measurement provides the greatest diagnostic performance for predicting glioma grade; however, the most accurate classification can be achieved by combining all of the imaging parameters.

Introduction The study was performed to compare dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) with 3-dimensional (3D) pseudocontinuous arterial spin labeling (PCASL) MRI in gliomas with an aim to see whether arterial spin labeling (ASL)-derived cerebral blood flow (CBF) values can be used as an alternative to DCE-MRI for its grading. Materials and methods Sixty-four patients with glioma (37 male; mean age, 43 years; 38 high grade and 26 low grade) underwent 3D-PCASL and DCE-MRI. The DCE indices (relative cerebral blood volume, rCBV; relative CBF, rCBF; permeability, k and kep; and leakage, ve) and ASL (absolute and rCBF) values were quantified from the tumors. Student independent t test was used to compare ASL and DCE-MRI indices. Pearson correlation was used to see correlation between DCE- and ASL-derived CBF values in tumor and normal parenchyma. Results On Student t test, neither ASL-derived absolute CBF (P = 0.78) nor rCBF (P = 0.12) values were found to be significantly different in 2 groups, whereas DCE indices except ve were significantly higher in high-grade gliomas. Arterial spin labeling-derived rCBF values weakly correlated with DCE-derived rCBF values, whereas these did not show correlation in normal grey (P = 0.12, r = 0.2) and white (P = 0.26, r = 0.14) matter regions. Conclusions Three-dimensional pseudocontinuous arterial spin labeling does not appear to be a reliable technique in the current form and may not be a suitable replacement for DCE in grading of glioma.

Obstructive sleep apnea (OSA) is characterized by recurrent upper airway blockage, with continued diaphragmatic efforts to breathe during sleep. Brain structural changes in OSA appear in various regions, including white matter sites that mediate autonomic, mood, cognitive, and respiratory control. However, the relationships between brain white matter changes and disease severity in OSA are unclear. This study examines associations between an index of tissue integrity, magnetization transfer (MT) ratio values (which show MT between free and proton pools associated with tissue membranes and macromolecules), and disease severity (apnea-hypopnea index [AHI]) in OSA subjects. We collected whole-brain MT imaging data from 19 newly diagnosed, treatment-naïve OSA subjects (50.4 ± 8.6 years of age, 13 males, AHI 39.7 ± 24.3 events/hr], using a 3.0-Tesla MRI scanner. With these data, whole-brain MT ratio maps were calculated, normalized to common space, smoothed, and correlated with AHI scores by using partial correlation analyses (covariates, age and gender; P0.005). Multiple brain sites in OSA subjects, including superior and inferior frontal regions, ventral medial prefrontal cortex and nearby white matter, midfrontal white matter, insula, cingulate and cingulum bundle, internal and external capsules, caudate nuclei and putamen, basal forebrain, hypothalamus, corpus callosum, and temporal regions, showed principally lateralized negative correlations (P0.005). These regions showed significant correlations even with correction for multiple comparisons (cluster-level, family-wise error, P0.05), except for a few superior frontal areas. Predominantly negative correlations emerged between local MT values and OSA disease severity, indicating potential usefulness of MT imaging for examining the OSA condition. These findings indicate that OSA severity plays a significant role in white matter injury. © 2016 Wiley Periodicals, Inc.

Heart failure (HF) patients show brain injury in autonomic, affective, and cognitive sites, which can change resting-state functional connectivity (FC), potentially altering overall functional brain network organization. However, the status of such connectivity or functional organization is unknown in HF. Determination of that status was the aim here, and we examined region-to-region FC and brain network topological properties across the whole-brain in 27 HF patients compared to 53 controls with resting-state functional MRI procedures. Decreased FC in HF appeared between the caudate and cerebellar regions, olfactory and cerebellar sites, vermis and medial frontal regions, and precentral gyri and cerebellar areas. However, increased FC emerged between the middle frontal gyrus and sensorimotor areas, superior parietal gyrus and orbito/medial frontal regions, inferior temporal gyrus and lingual gyrus/cerebellar lobe/pallidum, fusiform gyrus and superior orbitofrontal gyrus and cerebellar sites, and within vermis and cerebellar areas; these connections were largely in the right hemisphere (p

Purpose: To correlate phase and R2* derived from susceptibility-weighted magnetic resonance imaging (MRI) with computed tomography-Hounsfield (CT-HU) values in calcified neurocysticercosis and to evaluate phase imaging in the assessment of calcified neurocysticercosis. Materials and Methods: Thirty-five patients with 52 calcified lesions underwent both CT and MRI. Phase and R2* were calculated from multi-echo 3D-T2-star-weighted-angiography data. MRI and CT data were coregistered using mutual information. Spearman's correlation was performed between quantitative phase and CT-HU and R2* values. The Mann–Whitney U-test was used to see differences between CT-HU and R2* values from corresponding positive and negative phase regions. Results: The median values of CT-HU and R2* from regions with positive and negative phase were found to be 142.10 (range: 41.89–491.75) and 68.5/sec (range: 20–110/sec) and 137.30 (range: 30.83–458.88) and 69/sec (range: 0–110/sec), respectively. There was a significant correlation of positive phase values with corresponding CT-HU and R2* values. In addition, there was a significant correlation of R2* and CT-HU with negative phase values. Conclusion: We conclude that there is a significant correlation between negative and positive phase with CT-HU and R2* values, suggesting that the CT hyperdense lesion may have both calcium and other minerals, which can be differentiated using phase imaging. Conventional MRI should include phase imaging to detect calcified neurocysticercosis. J. Magn. Reson. Imaging 2011;. © 2011 Wiley Periodicals, Inc.

Background and aims Subacute combined degeneration (SACD) of the spinal cord, characterized by degeneration of lateral and posterior columns, is often found in vitamin B12 deficiency. Our aim was to look for sensitivity of imaging in depicting the spinal cord abnormality in vitamin B12 deficient patients and to find any correlation of vitamin B12 levels with clinical scores/severity at time of presentation. Material and methods A total 54 patients with biochemically proven vitamin B12 deficiency were included in the study. In all these patients MR study of cervico-dorsal spine was done. All the patients after initiation of appropriate treatment were followed up for a minimum of two months. Results MRI showed cord signal abnormality in only 8 patients out of 54 patients with low sensitivity of 14.8%. After appropriate therapy, complete resolution of cord signal abnormalities was observed in all these 8 patients, on follow-up MR imaging. Significant negative correlation (r = − 0.503, p Conclusion Conventional MRI may not be a useful tool for the diagnosis of SACD as it has very low sensitivity. Inverse correlation of Vitamin B12 levels with clinical scoring suggests that initial serum vitamin B12 levels may help in predicting the clinical severity.

BACKGROUND AND PURPOSE: Vitamin B12 deficiency may cause neural injury that results in cognitive deficits. The main purpose of our study was to evaluate morphometric and microstructural changes in the brain and relate them to cognition in subacute combined degeneration of the spinal cord and patients with biochemically deficient vitamin B12 . MATERIALS AND METHODS: Fifty-one patients were recruited and underwent nerve-conduction velocity tests and routine hematologic examinations. Serum vitamin B12 and homocystine levels were also measured. All patients and 46 age- and sex-matched controls underwent cervical spine and brain MR imaging along with cognition tests. MR imaging included conventional scans and DTI. Voxel-based morphometry was performed for determining the WM and GM volumes, based on T1-weighted images. DTI measures that included fractional anisotropy, ADC, radial diffusivity, and axial diffusivity were determined by using tract-based statistics. RESULTS: None of the patients showed any abnormality on conventional MR imaging. No significant changes in GM and WM volumes were observed in patients compared with controls. Significant reductions in the fractional anisotropy and an increase in ADC and radial diffusivity values were observed in multiple brain regions in patients compared with controls. These changes were confirmed on the region-of-interest analysis. Neuropsychological scores were significantly different in patients compared with controls and showed significant correlation with fractional anisotropy and radial diffusivity in a few brain regions. CONCLUSIONS: Microstructural changes are seen in WM regions on DTI in patients with vitamin B12 deficiency and correlate with cognition scores. DTI can be used for objective assessment of microstructural changes in the brain in vitamin B12 deficiency. ABBREVIATIONS: AD axial diffusivity; FA fractional anisotropy; MNI Montreal Neurological Institute; RD radial diffusivity; SACD subacute combined degeneration; TBSS tract-based spatial statistics

Purpose Magnetic resonance (MR) imaging and computed tomography (CT) are used almost exclusively in radiation therapy planning of glioblastoma multiforme (GBM), despite their well-recognized limitations. MR spectroscopic imaging (MRSI) can identify biochemical patterns associated with normal brain and tumor, predominantly by observation of choline (Cho) and N -acetylaspartate (NAA) distributions. In this study, volumetric 3-dimensional MRSI was used to map these compounds over a wide region of the brain and to evaluate metabolite-defined treatment targets (metabolic tumor volumes [MTV]). Methods and Materials Volumetric MRSI with effective voxel size of ∼1.0 mL and standard clinical MR images were obtained from 19 GBM patients. Gross tumor volumes and edema were manually outlined, and clinical target volumes (CTVs) receiving 46 and 60 Gy were defined (CTV 46 and CTV 60 , respectively). MTV Cho and MTV NAA were constructed based on volumes with high Cho and low NAA relative to values estimated from normal-appearing tissue. Results The MRSI coverage of the brain was between 70% and 76%. The MTV NAA were almost entirely contained within the edema, and the correlation between the 2 volumes was significant (r=0.68, P =.001). In contrast, a considerable fraction of MTV Cho was outside of the edema (median, 33%) and for some patients it was also outside of the CTV 46 and CTV 60 . These untreated volumes were greater than 10% for 7 patients (37%) in the study, and on average more than one-third (34.3%) of the MTV Cho for these patients were outside of CTV 60 . Conclusions This study demonstrates the potential usefulness of whole-brain MRSI for radiation therapy planning of GBM and revealed that areas of metabolically active tumor are not covered by standard RT volumes. The described integration of MTV into the RT system will pave the way to future clinical trials investigating outcomes in patients treated based on metabolic information.

Studies of brain tumors have identified altered tissue metabolism and water diffusion in MRI normal appearing tissue regions. In this retrospective study the relationship of these imaging measures with tumor grade in gliomas was investigated.MR spectroscopic imaging of whole brain and mean diffusivity (MD) measurements were obtained in subjects with untreated glioma and from normal control subjects. Mean metabolite values for N-acetylaspartate (NAA), total creatine (Cre), and total choline (Cho) were obtained in gray- and white-matter regions for the hemisphere contralateral to the tumor location, and MD values were obtained from contralateral normal-appearing white matter. Analyses tested for differences in mean values between subject groups while accounting for age.Analysis demonstrated increased NAA/Cre and MD, and decreased Cho/NAA for all tumor grades relative to control values. Differences between tumor grades were also observed for NAA, NAA/Cre, and Cho/NAA. Abnormal values of water diffusion were also observed, but with only a weak association between alterations in diffusion and tissue metabolites.This study supports previous observations of altered tissue metabolism and water diffusion in normal-appearing white matter while additionally finding differences of metabolite values in gray matter and an association with tumor grade.

Purpose: To modify the generalized tracer kinetic model (GTKM) by introducing an additional tissue uptake leakage compartment in extracellular extravascular space (LTKM). In addition, an implicit determination of voxel-wise local arterial input function (AIF) Cp(t) was performed to see whether these changes help in better discrimination between low- and high-grade glioma using dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI). Materials and Methods: The modified model (LTKM) was explored and fitted to the concentration–time curve C(t) of each voxel, in which the local AIF Cp(t) could be estimated by a time invariant convolution approximation based on a separately measured global AIF Ca(t). A comparative study of tracer kinetic analysis was performed on 184 glioma patients using DCE-MRI data on 1.5T and 3T MRI systems. Results: The LTKM analysis provided more accurate pharmacokinetic parameters as evidenced by their relative constancy with respect to the length of concentration–time curve used. In addition, LTKM with local AIF resulted in improved discrimination between low-grade and high-grade gliomas. Conclusion: LTKM with local AIF provides more accurate estimation of physiological parameters and improves discrimination between low-grade and high-grade gliomas as compared with GTKM. J. Magn. Reson. Imaging 2013;38:677–688. © 2013 Wiley Periodicals, Inc.