Functional MRI Examinations Research Articles

Diagnosis and Prognosis in Disorders of Consciousness: An Active Paradigm fMRI Study

Diagnoses in patients with disorders of consciousness are prone to misdiagnosis; thus, research has sought approaches to increase reliability, for instance, with functional MRI. By applying a motor imagery task, patients showing covert command following despite the absence of behavioural signs of awareness can be identified as being in a cognitive motor dissociation. This study seeks to determine the proportion of patients, with unresponsive wakefulness syndrome and minimally conscious state, who display covert command following. Moreover, the prognostic value of the improved diagnosis and different methodical approaches to analyse the functional MRI data were evaluated. 73 disorder of consciousness patients (35 unresponsive, 35 minimally conscious, and three already recovered) underwent weekly standardized behavioural assessments with the coma-recovery scale—revised and one functional MRI examination comparing their brain activations in the supplementary motor area between phases of imaging playing tennis and rest. 27 healthy controls served as a control group. The data was evaluated using different region-of-interest analyses (one- and two-tailed small-volume correction and region-of-interest exploration approaches) and a whole-brain analysis. Based on the one-tailed small volume correction data, seven patients, all of nontraumatic aetiology, showed covert command following. The one-tailed region-of-interest exploration identified three additional responders. 10 patients showed significantly more activation during rest than during the imagery paradigm (negative responders). 40% of patients (minimally conscious patients being three times more likely) showed significant activations in the whole brain analysis. Besides, no significant further associations were found between covert command following and clinical parameters. The analyses showed that the tennis paradigm could identify patients with cognitive motor dissociation with a nontraumatic aetiology, but our data failed to show any short-term prognostic validity. The relevance of negative responders and activated regions outside of the region of interest should be further investigated.

The rising role of cognitive reserve and associated compensatory brain networks in spinocerebellar ataxia type 2

Pre-existing or enhanced cognitive abilities influence symptom onset and severity in neurodegenerative diseases, which improve an individual’s ability to deal with neurodegeneration. This process is named cognitive reserve (CR), and it has acquired high visibility in the field of neurodegeneration. However, the investigation of CR has been neglected in the context of cerebellar neurodegenerative disorders. The present study assessed CR and its impact on cognitive abilities in spinocerebellar ataxia type 2 (SCA2), which is a rare cerebellar neurodegenerative disease. We investigated the existence of CR networks in terms of compensatory mechanisms and neural reserve driven by increased cerebello-cerebral functional connectivity. The CR of 12 SCA2 patients was assessed using the Cognitive Reserve Index Questionnaire (CRIq), which was developed for appraising life-span CR. Patients underwent several neuropsychological tests to evaluate cognitive functioning and a functional MRI examination. Network based statistics analysis was used to assess functional brain networks. The results revealed significant correlations of CRIq measures with cognitive domains and patterns of increased connectivity in specific cerebellar and cerebral regions, which likely indicated CR networks. This study showed that CR may influence disease-related cognitive deficits, and it was related to the effective use of specific cerebello-cerebral networks that reflect a CR biomarker.

Altered Functional Connectivity Density in Type 2 Diabetes Mellitus with and without Mild Cognitive Impairment.

Although disturbed functional connectivity is known to be a factor influencing cognitive impairment, the neuropathological mechanisms underlying the cognitive impairment caused by type 2 diabetes mellitus (T2DM) remain unclear. To characterize the neural mechanisms underlying T2DM-related brain damage, we explored the altered functional architecture patterns in different cognitive states in T2DM patients. Thirty-seven T2DM patients with normal cognitive function (DMCN), 40 T2DM patients with mild cognitive impairment (MCI) (DMCI), and 40 healthy controls underwent neuropsychological assessments and resting-state functional MRI examinations. Functional connectivity density (FCD) analysis was performed, and the relationship between abnormal FCD and clinical/cognitive variables was assessed. The regions showing abnormal FCD in T2DM patients were mainly located in the temporal lobe and cerebellum, but the abnormal functional architecture was more extensive in DMCI patients. Moreover, in comparison with the DMCN group, DMCI patients showed reduced long-range FCD in the left superior temporal gyrus (STG), which was correlated with the Rey auditory verbal learning test score in all T2DM patients. Thus, DMCI patients show functional architecture abnormalities in more brain regions involved in higher-level cognitive function (executive function and auditory memory function), and the left STG may be involved in the neuropathology of auditory memory in T2DM patients. These findings provide some new insights into understanding the neural mechanisms underlying T2DM-related cognitive impairment.

Evaluation of interstitial fibrosis in chronic kidney disease by multiparametric functional MRI and histopathologic analysis.

To investigate the diagnostic value of functional MRI to assess renal interstitial fibrosis in patients with chronic kidney disease (CKD). We prospectively recruited 80 CKD patients who underwent renal biopsies and 16 healthy volunteers to undergo multiparametric functional MRI examinations. The Oxford MEST-C classification was used to score the interstitial fibrosis. The diagnostic performance of functional MRI to discriminate interstitial fibrosis was evaluated by calculating the area under the receiver operating characteristic (ROC) curves. IgA nephropathy (60%) accounted for the majority of pathologic type in the CKD patients. Apparent diffusion coefficient (ADC) from diffusion-weighted imaging (DWI) was correlated with interstitial fibrosis (rho = -0.73). Decreased renal blood flow (RBF) derived from arterial spin labeling (rho = -0.78) and decreased perfusion fraction (f) derived from DWI (rho = -0.70) were accompanied by increased interstitial fibrosis. The T1 value from T1 mapping correlated with interstitial fibrosis (rho = 0.67) (all p < 0.01). The areas under the ROC curve for the discrimination of ≤ 25% vs. > 25% and ≤ 50% vs. > 50% interstitial fibrosis were 0.87 (95% confidence interval, 0.78 to 0.94) and 0.93 (0.86 to 0.98) by ADC, 0.84 (0.74 to 0.91) and 0.94 (0.86 to 0.98) by f, 0.93 (0.85 to 0.98) and 0.90 (0.82 to 0.96) by RBF, and 0.91 (0.83 to 0.96) and 0.77 (0.66 to 0.85) by T1, respectively. Functional MRI parameters were strongly correlated with the interstitial fibrosis of CKD. Therefore, it might a powerful tool to assess interstitial fibrosis of CKD noninvasively. • In CKD patients, the renal cortical ADC value decreased and T1 value increased significantly compared with healthy volunteers. • Functional MRI revealed significantly decreased renal perfusion in CKD patients compared with healthy volunteers. • The renal cortical ADC, f, RBF, and T1 values were strongly correlated with the interstitial fibrosis of CKD.

Intravoxel Incoherent Motion Diffusion-Weighted MR Imaging for Monitoring the Immune Response of Immunogenic Chemotherapy.

ObjectiveTo evaluate the predictive value of intravoxel incoherent motion (IVIM) diffusion-weighted imaging (DWI) in the quantitative assessment of conventional chemotherapy-activated immune responses in mouse tumor models and clinics.MethodsA total of 19 subcutaneous tumor-bearing mice were randomly divided into treated and control groups. Both groups had orderly IVIM DWI examinations before and on days 6 and 12 after the administration of cyclophosphamide (CPA) or saline. Pathologic examinations were performed, including HE staining and immunohistochemistry (IHC). The expressions of immune-related genes in the tumor were measured by qPCR. In addition, six patients with breast cancer requiring neoadjuvant chemotherapy (NACT) also underwent functional MRI examinations and IHC to determine potential antitumor immune response.ResultsAt the end of the study, the CPA treatment group showed the lowest tumor volume compared to the control group. For pathological examinations, the CPA treatment group showed a lower percentage of CD31 staining (P < 0.01) and Ki-67 staining (P<0.01), and a higher percentage of TUNEL staining (P < 0.01). The tumoral pseudodiffusion coefficient (D*) value showed a positive correlation with the CD31-positive staining rate (r = 0.729, P < 0.0001). The diffusion related parameters (D) value was positively correlated with TUNEL (r = 0.858, P < 0.0001) and negatively correlated with Ki-67 (r = -0.904, P < 0.0001). Moreover, a strong induction of the expression of the immune responses in the CPA treatment group was observed on day 12. D values showed a positive correlation with the Ifnb1-, CD8a-, Mx1-, Cxcl10- (r = 0.868, 0.864, 0.874, and 0.885, respectively, P < 0.0001 for all). Additionally, the functional MRI parameters and IHC results in patients with breast cancer after NACT also showed a close correlation between D value and CD8a (r = 0.631, P = 0.028).ConclusionsThe treatment response induced by immunogenic chemotherapy could be effectively evaluated using IVIM-DWI. The D values could be potential, sensitive imaging marker for identifying the antitumor immune response initiated by immunogenic chemotherapy.

Review/perspective on hysterical paralysis: A diagnosis of exclusion for spinal surgeons.

Background: Hysterical paralysis (HP) and/or conversion disorders (CD) are diagnoses of exclusion for spine surgeons. Before assigning this diagnosis to a patient, they must first undergo a full neurodiagnostic evaluation (i.e., X-rays, MR, CT/Myelo-CT) to rule out organic spinal pathology. Here, we reviewed select articles highlighting how to differentiate HP/CD patients from those with spinal disease.Methods: Several case studies and small series of patients with HP/CD were included in our analysis. Notably, prior to being assigned the diagnoses of HP/CD, patients had to first undergo X-ray, MR, CT, and/or Myelo-CT evaluations to rule out spinal disorders; typically, their neurodiagnostic studies were normal.Results: Patients with HP/CD often presented with varying clinical complaints of motor paralysis despite intact reflexes, normal sensory examinations, and lack of sphincter disturbance (i.e. intact rectal tone). Further, go and nogo functional MRI (fMRI) examinations demonstrated inconsistencies in areas of brain activation for patients with HP/CD complaints.Conclusions: HP/CD are diagnoses of exclusion, and patients should first undergo a full panel of neurodiagnostic studies to rule out organic spinal disease. While those with HP/CD should not have unnecessary operations, those with real “surgical pathology” should have appropriate spine surgery performed in a timely fashion.

Altered Spontaneous Brain Activity in Left-Behind Children: A Resting-State Functional MRI Study.

BackgroundParental migration has been associated with a higher risk of cognitive and behavioral abnormalities in left-behind children (LBC). This study aimed to explore the spontaneous brain activity in LBC and reveal the mechanisms underlying behavioral and cognitive abnormalities.MethodsInvolved LBC (n = 36) and non-LBC (n = 22) underwent resting-state functional MRI (fMRI) examination and cognitive and behavioral assessment. The fMRI-based amplitude of low-frequency fluctuation (ALFF) and fractional ALFF (fALFF) were assessed to analyze the spontaneous brain activity pattern. The relationships among abnormal spontaneous brain activity, behavioral and cognitive deficits and altered family environment were assessed by partial correlation analysis.ResultsCompared with non-LBC, LBC exhibited increased amplitude of low-frequency fluctuations in the right lingual gyrus (LING), while a decreased ALFF was observed in the bilateral insula and right orbital part of the middle frontal gyrus (ORBmid) (two-tailed voxel-level p < 0.01 and cluster-level p <0.05, Gaussian Random Field (GRF) correction). The fALFF in LBC were significantly increased in the left cerebellum 9 (Cbe9) and right cerebellum Crus2 (CbeCru2), while it decreased in the right hippocampus and left superior temporal gyrus (STG) (two-tailed voxel-level p < 0.01 and cluster-level p < 0.05, GRF correction). The ALFF and fALFF values in abnormal brain regions were found to be correlated with the learning ability, except for the right insula, while the fALFF values of the left STG were positively correlated with the full-scale IQ scores (p < 0.05). Moreover, the ALFF and fALFF values in all abnormal brain regions correlated with the education level of caregivers (p < 0.05).ConclusionsOur study provided empirical evidence that the lack of direct parental care during early childhood could affect brain function development involving cognition, behavior, and emotion. Our findings emphasized that intellectual and emotional cares are essential for LBC.

Alterations of Regional Homogeneity in Crohn's Disease With Psychological Disorders: A Resting-State fMRI Study

Abnormal psychological processing in the central nervous system has been found in Crohn's disease (CD) patients. Resting-state functional magnetic resonance images of 57 inactive and 58 active CD patients, and 92 healthy controls (HC) were obtained. The psychological assessment used a psychological questionnaire that was collected within 1 week before functional MRI examination. We investigated the neural basis of CD patients and the correlation among regional homogeneity (ReHo), clinical features and psychological assessment scores. We found that more severe psychological assessment disorder scores were observed in the active CD group than in the inactive CD group and HC group (P<0.001). Compared with HC, the active CD patients exhibited higher ReHo values in the frontal superior medial, frontal middle and lower values in the postcentral, supplementary motor area, and temporal middle. Meanwhile, inactive CD patients exhibited higher ReHo values in the frontal middle and lower ReHo values in the precentral, postcentral and putamen (all voxel P< 0.001, cluster P<0.01, corrected). The values of the frontal superior medial, postcentral and supplementary motor area were correlation with psychological assessment scores (r = 0.38, −0.41, −0.32, P = 0.001, 0.014, 0.003), and the clinical features of simple endoscopic score for Crohn's disease and erythrocyte sedimentation rate were negatively correlated with psychological assessment scores in active CD patients (r = −0.35, −0.34, P = 0.06, 0.08). These results provide evidence for abnormal resting-state brain activity in CD and suggest that the psychological of CD may play a critical role in brain function.

Machine Learning Classification of Mild Traumatic Brain Injury Using Whole-Brain Functional Activity: A Radiomics Analysis

Objectives To investigate the classification performance of support vector machine in mild traumatic brain injury (mTBI) from normal controls. Methods Twenty-four mTBI patients (15 males and 9 females; mean age, 38.88 ± 13.33 years) and 24 age and sex-matched normal controls (13 males and 11 females; mean age, 40.46 ± 11.4 years) underwent resting-state functional MRI examination. Seven imaging parameters, including amplitude of low-frequency fluctuation (ALFF), fractional amplitude of low-frequency fluctuation (fALFF), regional homogeneity (ReHo), degree centrality (DC), voxel-mirrored homotopic connectivity (VMHC), long-range functional connectivity density (FCD), and short-range FCD, were entered into the classification model to distinguish the mTBI from normal controls. Results The ability for any single imaging parameters to distinguish the two groups is lower than multiparameter combinations. The combination of ALFF, fALFF, DC, VMHC, and short-range FCD showed the best classification performance for distinguishing the two groups with optimal AUC value of 0.778, accuracy rate of 81.11%, sensitivity of 88%, and specificity of 75%. The brain regions with the highest contributions to this classification mainly include bilateral cerebellum, left orbitofrontal cortex, left cuneus, left temporal pole, right inferior occipital cortex, bilateral parietal lobe, and left supplementary motor area. Conclusions Multiparameter combinations could improve the classification performance of mTBI from normal controls by using the brain regions associated with emotion and cognition.

Analysis of abnormal dynamic functional connectivity of the raphe nucleus in adolescent patients with first-episode depression on resting-state functional magnetic resonance imaging

Objective: To investigate the dynamic functional connectivity (dFC) abnormalities of the raphe nucleus in adolescent patients with first-episode depression and its correlation with clinical characteristics and cognitive function. Methods: A total of 30 adolescent patients with untreated depression [Depression Groups, 17 males and 13 females, median age 16.5 (15.0, 17.0) years] and 29 age-, gender-and education-[Healthy Controls, 17 males and 12 females, median age 17.0 (16.0, 18.0) years] matched healthy controls underwent resting functional MRI examinations and their clinical data were obtained in the First Affiliated Hospital of Zhengzhou University.The raphe nuclei was subdivided into dorsal raphe nuclei (DRN) and median raphe nuclei (MRN). Seed-based dFC of the raphe nucleus was conducted to analyze the abnormal dFC between DRN and whole brain gray matter as well as MRN. Clinical characteristics and cognitive function were evaluated using HAMD-17 and Wisconsin card sorting (WSCT), respectively. The difference of dFC between the two groups was compared. The variance values of dFC in the different brain regions were extracted and subsequently used for evaluating the correlation between the scores of HAMD-17 as well as cognitive tests. Results: Compared with HC, the depression group had an significantly increased variance of dFC in the right superior temporal gyrus (MNI coordinate:33,-12,-12; voxel size 468; t=4.715), extending to the right insula, lentiform nucleus, putamen and Rolandic_Oper_R (aal) (GRF correction, voxel-P<0.005,cluster-P<0.05). Significant negative correlations were observed between the variance in the different brain regions and the total scores andthe factor of retardation scores of HAMD-17 as well the total time, the time of correct thinking, the time of mistake thinking and the number of non-persistent errors of WSCT in depression groups (r=-0.388, -0.365, -0.488, -0.470, -0.412, -0.390, respectively, all P<0.05). Conclusion: The variability of the dFC between the DRN and the temporal insula regions as well as striatum was increased in adolescent patients with untreated depression and associated with the severity and cognitive abnormality.

Real-time cognitive performance and positive symptom expression in schizophrenia

Deficits in cognitive functions are frequent in schizophrenia and are often conceptualized as stable characteristics of this disorder. However, cognitive capacities may fluctuate over the course of a day and it is unknown if such variation may be linked to the dynamic expression of psychotic symptoms. This investigation used Ecological Momentary Assessment (EMA) to provide mobile tests of cognitive functions and positive symptoms in real time. Thirty-three individuals with schizophrenia completed five EMA assessments per day for a one-week period that included real-time assessments of cognitive performance and psychotic symptoms. A subsample of patients and 31 healthy controls also completed a functional MRI examination. Relative to each individual’s average score, moments of worsened cognitive performance on the mobile tests were associated with an increased probability of positive symptom occurrence over subsequent hours of the day (coef = 0.06, p < 0.05), adjusting for the presence of psychotic symptoms at the moment of mobile test administration. These prospective associations varied as a function of graph theory indices in MRI analyses. These findings demonstrate that cognitive performance is prospectively linked to psychotic symptom expression in daily life, and that underlying brain markers may be observed in the Executive Control Network. While the potential causal nature of this association remains to be investigated, our results offer promising prospects for a better understanding of the underlying mechanisms of symptom expression in schizophrenia.

Network-level functional connectivity alterations in chemotherapy treated breast cancer patients: a longitudinal resting state functional MRI study

BackgroundPrevious studies have found abnormal structural and functional brain alterations in breast cancer survivors undergoing chemotherapy. However, the network-level brain changes following chemotherapy remain unknown. The purpose of this study was to investigate the dynamic changes of large-scale within- and between-network functional connectivity in chemotherapy-treated breast cancer patients.MethodsSeventeen breast cancer patients were evaluated with resting state functional MRI (rs-fMRI), neuropsychological tests and blood examination before postoperative chemotherapy (t0), one week after completing chemotherapy (t1) and six months after completing chemotherapy (t2). Nineteen age- and education level-matched healthy controls (HC) were also recruited. Independent components analysis (ICA) was performed to assess network component using rs-fMRI data. The functional network changes were then correlated with cognitive assessment scores and blood biochemical indexes.ResultsOne-way repeated measures ANOVA revealed significantly changed within-network functional connectivity in the anterior and posterior default mode network (ADMN and PDMN), left and right frontoparietal network (LFPN and RFPN), visual network and self-referential network. Post-hoc test showed that decreased within-network functional connectivity in ADMN, PDMN, LFPN, RFPN, SRN and central network one week after chemotherapy and increased six months after chemotherapy (all P < 0.05). As for the between-network functional connectivity, the PDMN- sensorimotor network connectivity showed the same tendency. Most of these within- and between-network functional connectivity changes were negatively associated with blood biochemical indexes and cognitive assessment scores (all P < 0.05).ConclusionsThese results indicated that chemotherapy may induce widespread abnormalities in resting state networks, which may serve as a potential biomarker of chemotherapy related cognitive impairment, providing insights for further functional recovery treatment.

Functional MRI in the pre-operative assessment of GI-RADS 3, 4, and 5 ovarian masses

BackgroundCharacterization of an ovarian lesion is a diagnostic challenge. A correct preoperative assessment is of great importance so as to arrange adequate therapeutic procedures. The aim of the current study is to evaluate the diagnostic performance of functional MRI in differentiation between malignant, borderline, and benign ovarian masses.ResultsThis study included 56 adnexal lesions. Bilateral synchronous ovarian lesions are detected in 16 cases. Postoperative histologically proved to be benign in 17 (30%), borderline (low potential malignancy) in 12 (22%), and malignant in 27 (48%). The overall diagnostic performance of conventional MRI in the diagnosis of adenexal lesion was a sensitivity of 74%, specificity of 47%, positive predictive value (PPV) of 76%, negative predictive value (NPV) of 44%, and an accuracy of 66%. Functional pelvic MRI examination showed an increase in overall diagnostic performance compared to conventional values with the highest sensitivity of 90% and NPV of 67% using DWI, and the highest specificity of 88%, PPV of 94%, and an accuracy of 82% using DCE MRI.ConclusionFunctional MRI in conjugation with conventional MRI plays a key role in the ovarian lesion detection, characterization, and staging. Functional MRI is currently being evaluated as possible predictive and prognostic biomarkers in ovarian lesions.

Disrupted resting-state spontaneous neural activity in stable COPD.

Introduction and aimAbnormal brain structure and function in COPD has been reported on MRI. However, the deficit in local synchronization of spontaneous activity in patients with stable COPD remains unknown. The main aim of the present study was to explore spontaneous brain activity in patients with COPD compared with normal controls using the regional homogeneity (ReHo) method based on resting-state functional MRI.MethodsNineteen patients with stable COPD and 20 well-matched (including age, sex, and number of years of education) normal controls who were recruited for the present study underwent resting-state functional MRI examinations and a series of neuropsychological and clinical assessments. The ReHo method was used to assess the strength of local brain signal synchrony. The mean ReHo values in brain areas with abnormal ReHo were evaluated with a receiver operating characteristic curve. The relationships between the brain regions with altered ReHo values and the clinical and neuropsychological parameters in COPD patients were assessed using Pearson’s correlation.ResultsPatients with COPD showed significantly lower ReHo values in the left occipital lobe and the right lingual, bilateral precuneus, and right precentral gyrus. The result of receiver operating characteristic curve analysis showed that the altered average ReHo values have high efficacy for distinguishing function. The mean lower ReHo values in the precuneus gyrus showed a significant positive correlation with FEV1%, FEV1/FVC, and orientation function but a significant negative correlation with arterial partial pressure of carbon dioxide.ConclusionThe COPD patients demonstrated abnormal synchrony of regional spontaneous activity, and the regions with abnormal activity were all correlated with visual processing pathways, which might provide us with a new perspective to further understand the underlying pathophysiology of cognitive impairment in patients with COPD.

Altered brain functional network in children with type 1 Gaucher disease: a longitudinal graph theory-based study.

Previous studies have investigated the brain structural abnormalities in children with type I Gaucher disease (GD). The purpose of our study is to investigate the topological efficiency of the brain functional network in children with type 1 GD. Twenty-two children diagnosed with type 1 GD and 22 sex- and age-matched healthy controls (HCs) underwent resting-state functional MRI (rs-fMRI) examination. For longitudinal study, the GD patients underwent rs-fMRI examination again after 4.6years. Graph theoretical analysis was used to assess the brain network topological properties at the global and regional levels. Compared with the HCs, the children with type 1 GD showed a decreased efficiency in functional segregation with a decreased γ (normalized clustering coefficient). In addition, the balance between functional segregation and integration was disrupted with decreased small-worldness (σ). At the regional level, the children with type 1 GD showed significantly decreased nodal degree and efficiency in the right precentral gyrus (PreCG.R) and left postcentral gyrus (PoCG.L). The significantly altered γ, σ, and nodal degree in the PreCG.R and PoCG.L were negatively correlated with the disease duration. No significant alterations in the global and regional topological properties were identified in these patients over time. Compared with that of the HCs, the efficiency of the brain functional network in the children with type 1 GD was disrupted, and regional involvement was located in motor- and sensory-related regions. The efficiency of the brain functional network in these patients remained stable over time.

Multiband fMRI as a plausible, time-saving technique for resting-state data acquisition: Study on functional connectivity mapping using graph theoretical measures

Background and objectivesEnsuring patient comfort and compliance by emphasizing reduced time frame for image acquisition, without compromising image quality is the key aspect with functional MRI examination. Multiband resting state fMRI (MB-rsfMRI) is a fairly new technique that potentially shortens MR image acquisition time by providing increased number of time points. The study aims to compare signal characteristics as well as the functional connectivity using conventional resting-state fMRI (rsfMRI) with that of MB-rsfMRI technique. Materials and methods9 healthy volunteers have prospectively undergone conventional resting-state fMRI and Multiband rsfMRI scanning technique in a 3T GE scanner (Discovery MR750w™). We compared the temporal SNR (tSNR) of conventional rs-fMRI with that of MB-rsfMRI. We looked at the language network connectivity and small world network characteristics from graph theoretical measures to compare the two techniques. ResultsWe computed the tSNR of conventional resting-state fMRI (rsfMRI) and MB-rsfMRI technique. A strong positive correlation was seen between graph theoretical measures from MB-rsfMRI and conventional rsfMRI (Pearson Correlation, r = 0.99). Both techniques showed similar small world network characteristics in healthy controls. ConclusionThe present study demonstrates negligible differences between the conventional-rsfMRI and MB-rsfMRI acquisitions on the computed graph theoretic measures. Accordingly current analysis proves that MB-rs-fMRI may be used as a time reducing acquisition technique that enables mapping of functional connectivity with similar outcome as conventional rs-fMRI in healthy subjects.

Altered Sensory Phenomena Experienced in Bipolar Disorder.

Altered Sensory Phenomena Experienced in Bipolar Disorder.

Functional MRI examination of empathy for pain in people with schizophrenia reveals abnormal activation related to cognitive perspective-taking but typical activation linked to affective sharing.

Schizophrenia is associated with important disturbances in empathy that are related to everyday functioning. Empathy is classically defined as including affective (sharing others' emotions) and cognitive (taking others' cognitive perspectives) processes. In healthy individuals, studies on empathy for pain revealed specific brain systems associated with these sets of processes, notably the anterior middle cingulate (aMCC) and anterior insula (AI) for affective sharing and the bilateral temporoparietal junction (TPJ) for the cognitive processes, but the integrity of these systems in patients with schizophrenia remains uncertain. Patients with schizophrenia and healthy controls performed a pain empathy task while undergoing fMRI scanning. Participants observed pictures of hands in either painful or nonpainful situations and rated the level of pain while imagining either themselves (self) or an unknown person (other) in these situations. We included 27 patients with schizophrenia and 21 healthy controls in our analyses. For the pain versus no pain contrast, patients showed overall typical activation patterns in the aMCC and AI, with only a small part of the aMCC showing reduced activation compared with controls. For the other versus self contrast, patients showed an abnormal modulation of activation in the TPJ bilaterally (extending to the posterior superior temporal sulcus, referred to as the TPJ/pSTS). The design included an unnecessary manipulation of the visual perspective that reduced the number of trials for analysis. The sample size may not account for the heterogeneity of schizophrenia. People with schizophrenia showed relatively intact brain activation when observing others' pain, but showed abnormalities when asked to take the cognitive perspectives of others.

Neuroanatomical assessment of the impact of negative emotion on explicit memory in patients with obsessive-compulsive disorder.

The aim of this study was to identify the brain activation patterns associated with emotionally neutral or unpleasant words during explicit memory tasks in patients with obsessive-compulsive disorder (OCD) using a functional MRI. Sixteen patients with OCD (mean age=31.4±10.1 years) and 16 healthy controls (mean age=32.6±5.8 years) who had no history of neurological or psychiatric illness underwent functional MRI examinations on a 3-T Siemens MR Scanner. The stimulation paradigm consisted of five times rest-condition, two times encoding of two-syllable words, and two times explicit retrieval of the previously learned words. Six different words were presented for 3 s each in the encoding and retrieval tasks. In the retrieval task, the same words as those used at the encoding task were presented randomly. Brain activation maps were quantified and analyzed using SPM8 and MRIcron software. During the explicit retrieval tasks with emotionally neutral words, the predominant activation areas observed in patients with OCD included the angular gyrus and the supramarginal gyrus, whereas healthy controls showed significantly higher activity in the postcentral gyrus (P<0.005). During the explicit retrieval tasks with unpleasant words, patients with OCD showed significantly higher activity, compared with healthy controls, in the cerebellum, posterior cingulate gyrus, middle occipital gyrus, middle temporal gyrus, and inferior frontal gyrus (P<0.005); however, no predominant activation areas in healthy controls over patients with OCD were observed. This study showed differential brain activation patterns in response to emotionally neutral and unpleasant words in patients with OCD. This finding will be useful in assessing the neural mechanisms associated with emotional effect on the impairment of memory retrieval in OCD.

SNR dependence on hardware installation and patient immobilization in fMRI examinations. MR imaging protocol optimization

Introduction The primary form of fMRI uses the blood-oxygen-level dependent (BOLD) contrast imaging. In BOLD fMRI imaging, the signal-to-noise ratio (SNR) is extremely low and statistical methods are used to extract quantitative data. SNR of the images obtained has to be maintained as high as possible. Purpose The aim of this study is to estimate the SNR dependence on the video and audio device hardware as well as the patient immobilization in event related functional MRI examinations. Materials and methods A head mimicking phantom printed on a commercial 3D printer was scanned on a clinical 1.5 T whole-body clinical scanner utilizing a standard fMRI sequence protocol. Both anatomical and functional MR sequences were used for data acquisition. SNR parametric maps were produced and were fused on both anatomical and functional MR images obtained. The phantom was scanned before and after the installation of all the fMRI stimulus devices (visual and audio). Further examination conditions referring to immobilization of the phantom and cable looping were also studied separately. Results SNR is reduced down to 30% when the hardware cables were looped. Immobilization of the head mimicking phantom affected SNR by reducing its value to a level of 10%. The whole fMRI hardware installation also affected SNR with discrepancies at a level of 10%. Conclusion The fMRI hardware pre-installation and patient immobilization are important factors that have to be taken into consideration before performing an fMRI examination, as they can both affect the already extremely low SNR of the obtained images.