Absent circle of Willis with vascular pollarding in an adult with colpocephaly: A developmental perspective.

Absent circle of Willis (COW) has been described in cases of severe forms of cerebral developmental anomalies such as alobar prosencephaly. However, there are no reports of absent COW in patients with a milder form of cerebral abnormality such as colpocephaly. We report a unique case of an adult with colpocephaly and absent COW and discuss their association from a developmental perspective.

Role of dynamic CT perfusion study in evaluating various intracranial space-occupying lesions.

AIMS: Differentiating intracranial mass lesions on CT scan is challenging. The purpose of our study was to determine the perfusion parameters in various intracranial space-occupying lesions (ICSOL), differentiate benign and malignant lesions, and differentiate between grades of gliomas. MATERIALS AND METHODS: We performed CT perfusion (CTP) in 64 patients, with age ranging from 17 to 68 years, having space-occupying lesions in brain and calculated relative cerebral blood flow (rCBF) and relative cerebral blood volume (rCBV). RESULTS: We found significantly lower perfusion in low-grade gliomas as compared to high-grade tumors, lymphoma, and metastases. Similarly in infective lesions, TWT and abscesses showed significantly lower perfusion compared to TOT. In ring enhancing lesions, capsule of TWT showed significantly lower perfusion as compared to abscesses, TOT, and metastases. CONCLUSION: Thus, in conclusion, infective lesions can be differentiated from tumors like lymphomas, high-grade gliomas, or metastases based on perfusion parameters. The cut off value of rCBV 1.64 can be used to differentiate between low grade and high grade gliomas. However, depending only on perfusion parameters, differentiation between the tumors like lymphomas, high-grade gliomas, and metastases may not be possible.

Gray matter volume deficits in spinocerebellar ataxia: an optimized voxel based morphometric study.

INTRODUCTION: Spinocerebellar ataxias (SCA) are a group of autosomal dominant ataxias with varied clinical phenotypes. However there are no unique distinguishing features on routine neuroimaging among the various genetically defined SCAs. Voxel-based morphometry (VBM) provides an automated unbiased analysis of structural MRI scans and gives a comprehensive assessment of anatomical differences throughout the brain. OBJECTIVES: The aims of this study were to (i) characterize the patterns of atrophy in SCA1, SCA2 and SCA3 using optimized VBM, (ii) demonstrate the characteristic anatomical differences in these genetically distinct SCA subtypes, and (iii) assess the relationship between morphometric measures and the CAG repeat lengths and other attributes of the disease. METHODS: Thirty-one genetically confirmed patients suffering from SCA (SCA1 - 12, SCA2 - 9, and SCA3 - 10) were studied. High resolution T1-weighted 3-Dimensional Magnetic Resonance Images of 31 patients were analyzed using the optimized VBM procedure. RESULTS: In all the three SCAs there was a significant loss of gray matter in both cerebellar hemispheres and vermis. Vermian atrophy was more pronounced in SCA3, while SCA1 and SCA2 had significant white matter atrophy. Pontine white matter atrophy was more pronounced in SCA2. In SCA1, the severity of ataxia strongly correlated with the degree of gray matter atrophy in cerebellar hemispheres. The duration of symptoms and lengths of CAG repeats had no correlation with the degree of atrophy. CONCLUSIONS: This study showed that the different subtypes of SCAs may have morphometric differences in the cerebellum, brainstem and the supratentorial structures.

Regional brain activation/deactivation during word generation in schizophrenia: fMRI study.

BACKGROUND: Examination of the brain regions that show aberrant activations and/or deactivations during semantic word generation could pave the way for a better understanding of the neurobiology of cognitive dysfunction in schizophrenia. AIMS: To examine the pattern of functional magnetic resonance imaging blood oxygen level dependent activations and deactivations during semantic word generation in schizophrenia. METHOD: Functional magnetic resonance imaging was performed on 24 participants with schizophrenia and 24 matched healthy controls during an overt, paced, 'semantic category word generation' condition and a baseline 'word repetition' condition that modelled all the lead-in/associated processes involved in the performance of the generation task. RESULTS: The brain regions activated during word generation in healthy individuals were replicated with minimal redundancies in participants with schizophrenia. The individuals with schizophrenia showed additional activations of temporo-parieto-occipital cortical regions as well as subcortical regions, despite significantly poorer behavioural performance than the healthy participants. Importantly, the extensive deactivations in other brain regions during word generation in healthy individuals could not be replicated in those with schizophrenia. CONCLUSIONS: More widespread activations and deficient deactivations in the poorly performing participants with schizophrenia may reflect an inability to inhibit competing cognitive processes, which in turn could constitute the core information-processing deficit underlying impaired word generation in schizophrenia.

Schneiderian first rank symptoms and inferior parietal lobule cortical thickness in antipsychotic-naïve schizophrenia.

Inferior parietal lobule (IPL) is implicated in the pathogenesis of first rank symptoms (FRS) in schizophrenia by functional neuroimaging studies. However, the relationship between IPL cortical thickness and FRS is yet to be explored. In this study, cortical thickness of IPL was analyzed in antipsychotic-naïve schizophrenia patients (total number = 51) with [FRS(+); N = 25] and those without FRS [FRS(-); N = 26] in comparison with group-matched healthy controls (N = 47). FRS(+) patients showed significant cortical thickness deficit in right IPL (specifically angular gyrus) in comparison with both FRS(-) patients (p = 0.005) and healthy controls (p = 0.0002); lack of difference on the left side might possibly be related to larger variance in healthy controls. Deficient cortical thickness involving IPL in FRS(+) schizophrenia patients adds further support to the role of internal monitoring system in the pathogenesis of FRS in schizophrenia.

Functional magnetic resonance imaging in primary writing tremor and writer's cramp: A pilot study.

OBJECTIVES: The precise pathophysiology of primary writing tremor (PWT) and writer's cramp (WC) is not known. The aim of this study is to compare the cerebral activation patterns in patients of PWT, WC and healthy controls, during a task of signing on paper, using functional magnetic resonance imaging (fMRI). MATERIALS AND METHODS: Six subjects with PWT, three with WC and six healthy volunteers were examined using a 1.5-Tesla scanner. The paradigm consisted of three times repetition of a set of period of rest and activity. Each set consisted of 10 blood oxygen level dependent (BOLD) echo-planar imaging (EPI) acquisitions at rest followed by 10 BOLD EPI acquisitions while signing their names on paper using the dominant right hand. Entire brain was covered. SPM99 analysis was done. RESULTS: IN COMPARISON TO THE HEALTHY CONTROLS, THE FOLLOWING DIFFERENCES IN CEREBRAL ACTIVATION WERE NOTED IN THE PATIENTS: (a) primary and supplementary motor areas showed overactivation in patients of PWT and underactivation in patients of WC, (b) the cingulate motor area showed underactivation in patients of PWT and overactivation in patients of WC and (c) the cerebellar activity was reduced in both WC and PWT. CONCLUSION: Our preliminary findings suggest that the cerebral and cerebellar activation patterns in PWT and WC during signing on paper are distinct from each other and from healthy controls. There may be cerebellar dysfunction in addition to motor dysfunctions in the pathogenesis of these disorders.

Corpus callosum deficits in antipsychotic-naïve schizophrenia: evidence for neurodevelopmental pathogenesis.

The corpus callosum (CC), the largest inter-hemispheric tract connecting the association cortices, has been shown to be affected in disorders with aberrant neurodevelopment. Previous studies that investigated CC abnormalities in schizophrenia have reported mixed findings potentially due to various confounding factors. In this study, we used magnetic resonance imaging to examine a large sample of antipsychotic-naïve schizophrenia patients (n=66) in comparison with age-, sex-, and handedness-matched (as a group) healthy comparison subjects (n=46). Mid-sagittal areas of CC sub-regions--namely, the genu, body, isthmus and splenium--were measured based on Witelson's method with good inter- and intra-rater reliability. The genu and body of the CC were significantly smaller in schizophrenia patients in comparison to healthy subjects after controlling for the potential confounding effects of age, sex and intracranial area. In male schizophrenia patients, there was a significant positive correlation between the age at onset of psychosis and the area of the genu. Together, these findings suggest neurodevelopmentally mediated hypoconnectivity in schizophrenia.

High energy phosphate abnormalities normalize after antipsychotic treatment in schizophrenia: a longitudinal 31P MRS study of basal ganglia.

We reported increased high-energy phosphate metabolism in the basal ganglia of antipsychotic-naïve schizophrenia patients using (31)P Magnetic Resonance Spectroscopy (MRS). These patients were followed up for 1 year and and reassessed using (31)P MRS. Fourteen (8 males) patients with DSM-IV schizophrenia and 14 (11 males) healthy controls underwent (31)P MRS of sub-cortical structures (predominantly basal ganglia) twice (mean+/-S.D. interscan interval 1.15+/-0.17year) on a 1.5T scanner. Total scores on the Positive and Negative Syndrome Scale (PANSS) decreased significantly after treatment in schizophrenia patients. Patients had significantly lower mean PCr/ATP ratios than healthy controls at baseline but not during the follow-up. In patients, there was a significant positive correlation between the magnitude of improvement in PANSS total scores and the extent of change in the PCr/ATP ratio. Findings support the hypothesis that reduction of energy demand or induction of decreased energy-demanding processes might underlie the mechanism of action of antipsychotics in schizophrenia.

A functional Magnetic Resonance Imaging study of neurohemodynamic abnormalities during emotion processing in subjects at high risk for schizophrenia.

BACKGROUND: Emotion processing abnormalities are considered among the core deficits in schizophrenia. Subjects at high risk (HR) for schizophrenia also show these deficits. Structural neuroimaging studies examining unaffected relatives at high risk for schizophrenia have demonstrated neuroanatomical abnormalities involving neo-cortical and sub-cortical brain regions related to emotion processing. The brain functional correlates of emotion processing in these HR subjects in the context of ecologically valid, real-life dynamic images using functional Magnetic Resonance Imaging (fMRI) has not been examined previously. AIM: To examine the neurohemodynamic abnormalities during emotion processing in unaffected subjects at high risk for schizophrenia in comparison with age-, sex-, handedness- and education-matched healthy controls, using fMRI. MATERIALS AND METHODS: HR subjects for schizophrenia (n=17) and matched healthy controls (n=16) were examined. The emotion processing of fearful facial expression was examined using a culturally appropriate and valid tool for Indian subjects. The fMRI was performed in a 1.5-T scanner during an implicit emotion processing paradigm. The fMRI analyses were performed using the Statistical Parametric Mapping 2 (SPM2) software. RESULTS: HR subjects had significantly reduced brain activations in left insula, left medial frontal gyrus, left inferior frontal gyrus, right cingulate gyrus, right precentral gyrus and right inferior parietal lobule. Hypothesis-driven region-of-interest analysis revealed hypoactivation of right amygdala in HR subjects. CONCLUSIONS: Study findings suggest that neurohemodynamic abnormalities involving limbic and frontal cortices could be potential indicators for increased vulnerability toward schizophrenia. The clinical utility of these novel findings in predicting the development of psychosis needs to be evaluated.

Neuroanatomical correlates of neurological soft signs in antipsychotic-naive schizophrenia.

Recent imaging studies suggest that the so-called "soft" neurological signs in schizophrenia might have neuroanatomical validity. We examined gray matter volume correlates of neurological soft signs (NSS) in antipsychotic-naive schizophrenia patients using an automated image analysis technique. NSS were assessed using a modified neurological evaluation scale with good inter-rater reliability. Magnetic resonance images of 30 schizophrenia patients and 27 age-, sex-, education- and handedness-matched healthy controls were processed using optimized voxel-based morphometry (VBM). Logistic regression analysis showed that only the Motor Sequencing Signs (MSS) sub-score was a significant predictor of subject's status among the NSS sub-scores. Optimized VBM analysis showed that the MSS sub-score had a significant negative correlation with total and regional gray matter volumes (prefrontal, posterior cingulate, temporal cortices, putamen, and cerebellum) in schizophrenia patients but not in controls. Prefrontal and temporal cortices, putamen and cerebellum had significant volume deficits in patients. Cortical and cerebellar correlates of the sub-score MSS support the concept of "cognitive dysmetria" in schizophrenia.

Investigating paranormal phenomena: Functional brain imaging of telepathy.

AIM: "Telepathy" is defined as "the communication of impressions of any kind from one mind to another, independently of the recognized channels of sense". Meta-analyses of "ganzfield" studies as well as "card-guessing task" studies provide compelling evidence for the existence of telepathic phenomena. The aim of this study was to elucidate the neural basis of telepathy by examining an individual with this special ability. MATERIALS AND METHODS: Using functional MRI, we examined a famous "mentalist" while he was performing a telepathic task in a 1.5 T scanner. A matched control subject without this special ability was also examined under similar conditions. RESULTS: The mentalist demonstrated significant activation of the right parahippocampal gyrus after successful performance of a telepathic task. The comparison subject, who did not show any telepathic ability, demonstrated significant activation of the left inferior frontal gyrus. CONCLUSIONS: The findings of this study are suggestive of a limbic basis for telepathy and warrant further systematic research.

Corpus callosum abnormalities associated with greater externalizing behaviors in subjects at high risk for alcohol dependence.

Subjects at high risk for alcoholism have a greater propensity for externalizing behaviors and brain volume reductions of possible neurodevelopmental origin. Morphometric deficits in the corpus callosum (CC), which might reflect this neurodevelopmental abnormality, have been reported in other externalizing disorders such as attention deficit hyperactivity disorder, but not in subjects at high risk for alcoholism. The objective of the current study was to evaluate the CC morphometry in subjects at high risk for alcoholism. Magnetic resonance images of the CC in high-risk subjects (n=20) were compared with those of low-risk subjects matched to the high-risk subjects for age, sex, and handedness (n=20). Mid-sagittal areas of the CC, genu, body, isthmus and splenium were measured based on Witelson's method with good inter- and intra-rater reliability. Externalizing behaviors were assessed using the Semi-Structured Assessment for Genetics of Alcoholism-II. Total CC, genu and isthmus areas were significantly smaller in high-risk than low-risk subjects after controlling for age and intracranial area. The total externalizing symptoms score had a significant negative correlation with genu and isthmus areas. Smaller CC areas and their negative association with externalizing behaviors may represent yet another marker of susceptibility to alcoholism in high-risk subjects.

Gray matter volume abnormalities and externalizing symptoms in subjects at high risk for alcohol dependence.

Reduced right amygdala volumes have been reported in young, alcohol-naïve subjects at high risk (HR) for alcohol dependence. The differences in brain morphometry have been associated with an excess of externalizing behaviors in these subjects. This may reflect a neurobiological vulnerability to alcohol dependence. Existing Magnetic Resonance Imaging (MRI) studies on these subjects have examined only a few, pre-selected brain regions using the manual regions of interest (ROI) approach. MRI of HR subjects (n = 20) and age, sex, and handedness-matched low-risk (LR) subjects (n = 21) were analyzed using optimized voxel-based morphometry and ROI approach. The externalizing symptoms of these subjects and their fathers were measured using the Semi-Structured Assessment for the Genetics of Alcoholism. HR subjects had significantly smaller volumes of superior frontal, cingulate and parahippocampal gyri, amygdala, thalamus and cerebellum. These gray matter volumes correlated negatively with externalizing symptoms scores. Subjects at HR for alcoholism have reduced volumes of critical areas of brain gray matter, which are associated with increased externalizing symptoms. These represent key endophenotypes of alcoholism.

Intracranial metastatic mucinous adenocarcinoma with characteristic features on diffusion-weighted imaging and in vivo magnetic resonance spectroscopy.

Intracranial abscesses and metastases are common lesions that might not be differentiated on routine MRI alone. In vivo proton spectroscopy and diffusion-weighted imaging have been used as complementary investigations for improved tissue characterization. In the present report we illustrate the role of mucin and its contribution to signal characteristics on diffusion-weighted imaging in a metastatic mucinous adenocarcinoma.