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PubMedDate not supplied

[Neuropsychological consequences of perinatal asphyxia].

Perinatal asphyxia has been classically related to important neurological diseases such as cerebral palsy, but it it also stated that a high percentage of child with a good outcome did not show any sequelae. We reviewed cerebral lesions demonstrated by post-mortem analysis and the structural MRI contributions to the anatomo-functional correlates. The most frequent neuropsychological disturbances showed by these patients in the general intelligence, perceptive functions, memory and emotional and social behavior were also summarized.

Asphyxia Neonatorum↗
PubMed1998

[Progressive aphasia without dementia].

INTRODUCTION: Slowly progressive aphasia without generalized dementia is considered as a degenerative disorder that can be differentiated of others well-known neurodegenerative disorders. CLINICAL CASE: We present a case report of a patient with slowly progressive aphasia, characterized by a progressive anomia and without generalized dementia. The patient was evaluated in the last four years: a neuropsychological assessment, a neurological exploration and structural (MRI) and functional (SPECT) neuroimaging were performed. CONCLUSION: This case is interesting on account of a selective implication of the left temporal hemisphere is showed in the pathogenesis of this disorder.

Anomia↗
PubMed1995

Use of MRI for measuring structures in frozen postmortem brain.

A method was developed for magnetic resonance imaging (MRI) of human autopsy brains stored long-term at -70 degrees C. Scanning brains at temperatures between -70 and -8 degrees C gave minimal MRI signals consistent with protons having limited freedom of movement at low temperature. Raising brain temperature improved the signal such that scanning at -1 degree C generated images with good in-plane resolution, grey/white matter contrast, and fine detail of cortical sulcal/gyral patterns. To validate the method, volume and area measurements were made using computerized image analysis on stored digital images of 14 brains from adult subjects of both genders and various ages. The data confirmed that brain volume was inversely correlated with age, and female subjects had smaller brains. This is a valuable new method for acquiring morphometric data from previously unscanned pathologic brains that are to be used for neurochemical and molecular investigations.

Analysis of Variance↗
PubMed1999

MRI anatomy of schizophrenia.

Structural magnetic resonance imaging (MRI) data have provided much evidence in support of our current view that schizophrenia is a brain disorder with altered brain structure, and consequently involving more than a simple disturbance in neurotransmission. This review surveys 118 peer-reviewed studies with control group from 1987 to May 1998. Most studies (81%) do not find abnormalities of whole brain/intracranial contents, while lateral ventricle enlargement is reported in 77%, and third ventricle enlargement in 67%. The temporal lobe was the brain parenchymal region with the most consistently documented abnormalities. Volume decreases were found in 62% of 37 studies of whole temporal lobe, and in 81% of 16 studies of the superior temporal gyrus (and in 100% with gray matter separately evaluated). Fully 77% of the 30 studies of the medial temporal lobe reported volume reduction in one or more of its constituent structures (hippocampus, amygdala, parahippocampal gyrus). Despite evidence for frontal lobe functional abnormalities, structural MRI investigations less consistently found abnormalities, with 55% describing volume reduction. It may be that frontal lobe volume changes are small, and near the threshold for MRI detection. The parietal and occipital lobes were much less studied; about half of the studies showed positive findings. Most studies of cortical gray matter (86%) found volume reductions were not diffuse, but more pronounced in certain areas. About two thirds of the studies of subcortical structures of thalamus, corpus callosum and basal ganglia (which tend to increase volume with typical neuroleptics), show positive findings, as do almost all (91%) studies of cavum septi pellucidi (CSP). Most data were consistent with a developmental model, but growing evidence was compatible also with progressive, neurodegenerative features, suggesting a "two-hit" model of schizophrenia, for which a cellular hypothesis is discussed. The relationship of clinical symptoms to MRI findings is reviewed, as is the growing evidence suggesting structural abnormalities differ in affective (bipolar) psychosis and schizophrenia.

Brain↗
PubMedDate not supplied

Assessment of posterior fossa structures with midsagittal MRI: the effects of age.

Midsagittal magnetic resonance (MR) images of 36 normal volunteers, ranging in age from 26 to 79 years, were used to evaluate the effects of age on the size of posterior fossa structures (cerebellar vermis, midbrain, pons, medulla and fourth ventricle). Our results demonstrate a highly statistically significant age-related decline in the cross-sectional area of the midbrain (r = -.44, p less than 0.007), a less prominent decline in the area of the anterior cerebellar vermis (r = -.33, p less than 0.05) and striking intercorrelations between the dimensions of the pons, medulla and cerebellar vermis. To the best of our knowledge, this is the first MRI demonstration of midbrain atrophy during aging in normal adults.

Adult↗
PubMed2002

(18)F-FDG PET in localization of frontal lobe epilepsy: comparison of visual and SPM analysis.

UNLABELLED: The sensitivity of (18)F-FDG PET to localize epileptogenic zones in frontal lobe epilepsy was evaluated by both visual assessment and statistical parametric mapping (SPM). METHODS: Twenty-nine patients with frontal lobe epilepsy were examined. All patients showed good outcome after surgical resection (Engel class I or II). On pathologic examination, 22 patients had cortical dysplasia, 4 had tumors, 1 had cortical scars, and 2 had an old infarct. Hypometabolic lesions were found on (18)F-FDG PET images by both visual assessment and SPM analysis. On SPM analysis, the cutoff threshold was varied and sensitivity to find epileptogenic zones was compared. RESULTS: MRI showed structural lesions in 15 patients and normal findings in 14. (18)F-FDG PET correctly localized the epileptogenic zones in 16 patients (55%) by visual assessment. The sensitivity of (18)F-FDG PET was 36% in patients without structural lesions on MRI and 73% in patients with structural lesions. On SPM analysis, using an uncorrected probability value of 0.005 as the threshold, the sensitivity of SPM analysis was 66%, which was not statistically different from the sensitivity of visual assessment. The sensitivity decreased according to the decrease in probability value. CONCLUSION: (18)F-FDG PET was sensitive in localizing epileptogenic zones by revealing hypometabolic areas in nonlesional patients with frontal lobe epilepsy as well as in lesional patients. SPM analysis showed a comparable sensitivity to visual assessment and could be used as an aid in diagnosing epileptogenic zones in frontal lobe epilepsy.

Adult↗
PubMed2001

Unfolding the human hippocampus with high resolution structural and functional MRI.

The hippocampus is a region of the brain that is crucial to memory function. Functional neuroimaging allows for the noninvasive investigation of the neurophysiology of human memory by observing changes in blood flow in the brain. We have developed a technique that employs high-resolution functional magnetic resonance imaging (fMRI) in combination with cortical unfolding to provide activation maps of the hippocampal region that surpass in anatomic and functional detail other methods of in vivo human brain mapping of the medial temporal lobe. We explain the principles behind this method and illustrate its application to a novelty-encoding paradigm.

Brain Mapping↗
PubMed2001

Does the trabecular bone structure depicted by high-resolution MRI of the calcaneus reflect the true bone structure?

RATIONALE AND OBJECTIVES: The purpose of this study was to compare trabecular bone structure parameters assessed with high-resolution magnetic resonance imaging (HR-MRI) with those determined in specimen sections. METHODS: High-resolution MR images were obtained for 30 calcaneus specimens with a three-dimensional, T1-weighted spin-echo sequence (spatial in-plane resolution 0.195 mm, slice thicknesses of 0.3 and 0.9 mm). Thirty-eight sections were obtained from the specimens, and contact radiography was performed. In the corresponding sections, structural parameters analogous to bone histomorphometry were determined. RESULTS: Significant correlations between MRI-derived structural parameters and those derived from macro pathological sections were found: r values of up to 0.75 were obtained (P < 0.01). The highest correlations were found for apparent bone volume/total volume and trabecular thickness. Image thresholding techniques showed a significant impact on these correlations (P < 0.01). The thinner MR sections were less susceptible to the different thresholding algorithms. CONCLUSIONS: Trabecular bone structure depicted by HR-MR images is significantly correlated with that shown in macro sections (P < 0.01); however, a number of limitations have to be considered, including the substantial impact of thresholding techniques and slice thickness.

Aged↗
PubMed2001

Inner ear fluid volumes and the resolving power of magnetic resonance imaging: can it differentiate endolymphatic structures?

Magnetic resonance imaging (MRI) can accurately recognize minute volumes as small as 1 mm3. The volumes of the utricle and saccule of the inner ear are within the resolving power of MRI, but these structures cannot be recognized because the endolymph and perilymph signals are identical. To clarify the interpretation and description of inner ear structures on MRI, we measured and calculated the volumes of the perilymphatic and endolymphatic spaces of the human ear. We found the total volume of the bony labyrinth to be approximately 192.5 mm3 (endolymph, 34.0 mm3; perilymph, 158.5 mm3).

Ear, Inner↗
PubMed1999

Parkinson's disease: a novel MRI method for determining structural changes in the substantia nigra.

OBJECTIVES: To use MRI in a novel way to image and quantify the changes occurring in the substantia nigra in Parkinson's disease. METHODS: Six patients with idiopathic Parkinson's disease were compared with six age matched control subjects. The subjects were imaged using a combination of pulse sequences hypothesised to be sensitive to cell loss. RESULTS: The images showed patterns of change in patients with Parkinson's disease. Highly significant differences between the patients and control population were found (p<0.001). CONCLUSIONS: This methodology suggests the possibility of detecting presymptomatic disease in those judged to be at risk, and also in confirming the diagnosis in patients with early disease. Furthermore, the technique seems to hold promise as a means for staging the disease, and possibly differentiating other forms of parkinsonism.

Adult↗
PubMedDate not supplied

Anatomical MRI findings in mood and anxiety disorders.

OBJECTIVE: In vivo structural magnetic resonance imaging (MRI) studies have evaluated the brain anatomy of various psychiatric disorders, allowing the investigation of putative abnormal brain circuits possibly involved in the patophysiology of psychiatric disorders. Here we reviewed the structural MRI literature in mood and anxiety disorders. METHODS: All anatomical MRI studies evaluating mood and anxiety disorder patients were identified through a comprehensive Medline search conducted for the period from 1966 to January 2002, and a manual search of bibliographic cross-referencing complemented the Medline search. RESULTS: Differential patterns of anatomical brain abnormalities appear to be involved in subtypes of mood disorders, with hippocampus and basal ganglia being abnormal in unipolar disorder, and amygdala and cerebellum in bipolar disorders, suggesting that these two mood disorders are biologically distinct. As for anxiety disorders, orbital frontal regions and basal ganglia have been reported to be anatomically abnormal in obsessive-compulsive disorder, temporal lobe was found to be abnormally reduced in panic disorder, and abnormal hippocampus shrinkage was shown in posttraumatic stress disorder. CONCLUSIONS: The structural MRI findings reviewed here suggest abnormalities in specific brain regions participating in proposed neuroanatomic models possibly involved in the pathophysiology of mood disorders and anxiety disorders. Nonetheless, available MRI studies have suffered from limitations related to relatively small patient samples and involvement of medicated patients, and were largely cross-sectional investigations. Therefore, longitudinal MRI studies involving more sizeable samples of drug-free patients, patients at first episode of illness or at high risk for mood or anxiety disorders, associated to genetic studies, are likely to be extremely valuable to separate state from trait brain abnormalities and to characterize further the pathophysiology of these disorders.

Anxiety Disorders↗
PubMed2002

Serial MRI evaluation of cardiac structure and function in mice after reperfused myocardial infarction.

This study evaluated the utility of cardiac MRI for assessing the impact of myocardial infarction (MI) on cardiac structure and function in mice following reperfused 1- or 2-hr occlusions of the left anterior descending coronary artery (LAD). When assessed 1 day after MI, the left ventricular ejection fraction (LVEF) had declined by more than half, and remained depressed for the duration of the study. Furthermore, MI initiated dramatic increases in both LV end-systolic volume (LVESV) and end-diastolic volume (LVEDV), with a greater than threefold increase in LVESV and a twofold increase in LVEDV by 4 weeks post-MI. Transmural LV wall thickening (WTh) analysis revealed that noninfarcted myocardium in the remote septal region exhibited an early deficit in contractile function after MI that transiently resolved by day 7, only to be followed by a late phase of dysfunction that became fully manifest by day 28 post-MI. In conclusion, MRI allows the serial assessment of cardiac structure and function after MI in mice, with a resolution adequate to document both regional and temporal changes. The application of these imaging techniques in transgenic and knock-out mice will greatly expedite research aimed at defining the functional roles of individual genes in the pathophysiology of LV remodeling (LVR) after reperfused MI.

Animals↗
PubMed2000

Functional MRI in children with congenital structural abnormalities of the occipital cortex.

Functional MRI techniques were used to map the position of visual cortex in an awake and a sedated child with congenital anomalies of the posterior hemispheres. In one subject with cortical heterotopia, an activated cortex was found distinct from the structurally abnormal area detected on conventional MRI. In a sedated patient with holoprosencephaly, activated cortical areas in the posterior-medial portions of the hemispheres were identified. This study demonstrates the utility of functional MRI in such patients, both awake and sedated.

Adolescent↗
PubMed2002

Volumetric structural magnetic resonance imaging (MRI) of the rat hippocampus following kainic acid (KA) treatment.

An in vivo MRI study employing a high field (7T) magnet and a T1- and T2-weighted imaging sequence with subsequent histopathological evaluations was undertaken to develop and evaluate MRI-based volumetric measurements in the rat. The brain structures considered were the hippocampus, the cingulate cortex, the retrosplenial granular cortex and the ventricles. Control (n=3) and kainic acid (KA; n=4) treated rats were scanned 10 days following the manifestation of stage four seizures. The MRI images exhibited anatomical details (125 microm in-plane resolution) that enabled volumetric analysis with high intra-rater reliability. Volumetric analysis revealed that KA-treated rats had significantly smaller hippocampi, and a significant increase in ventricular size. The cingulate cortex and the retrosplenial granular cortex did not differ in volume between the two groups. The histological observations supported the MRI data showing neuronal loss and neuronal degeneration in CA1 and CA3 of the hippocampus, which was accompanied by strong microglia activation. These data demonstrate a reliable and valid method for the measurement of the rat hippocampus in vivo using MRI with a high field magnet, thereby providing a useful tool for future studies of rodent models of neuro-degenerative diseases.

Animals↗
PubMed1997

The relation between quantitative MRI measures of hippocampal structure and the intracarotid amobarbital test.

PURPOSE: The increasing sophistication of quantitative magnetic resonance imaging (MRI) techniques has generated hopes that they may eventually supersede the intracarotid amobarbital procedure (IAP) in the presurgical screening for bilateral abnormalities in prospective candidates for temporal lobe epilepsy surgery. As the first step toward this aim, the purpose of this study was to examine the relationship between these measures of structural and functional integrity. METHODS: We examined the relation between memory performance and pass/fail rates on the IAP and two MRI measures of hippocampal integrity: hippocampal volumes, adjusted for intracranial volume (HCvol) and hippocampal T2 relaxometry (HCT2), in 48 patients with medically intractable temporal lobe epilepsy, who underwent the IAP as part of their presurgical evaluation for temporal lobectomy. RESULTS: The unilateral memory scores from the IAP were not significantly correlated with the corresponding HCvol or HCT2 measures in the right- and left-temporal-lobe groups. However, the MRI measures of hippocampal asymmetry (right minus left HCvol, right minus left HCT2) were significantly correlated with our measure of functional asymmetry, the right minus left hemisphere memory score from the IAP, supporting the role of the IAP in lateralising temporal lobe dysfunction. Forty-six patients with unilateral hippocampal sclerosis and concordant EEG studies passed the IAP. Two patients failed the memory component of the IAP. In both cases, other presurgical investigations suggested bilateral abnormalities. CONCLUSIONS: We conclude that patients with unilateral hippocampal sclerosis, established by a rigorous quantitative MRI protocol, and concordant ictal and interictal EEG findings may not be at risk for postoperative amnesia, despite baseline neuropsychological deficits suggestive of bilateral disturbance.

Adult↗
PubMed2001

Separate and interactive effects of cocaine and alcohol dependence on brain structures and metabolites: quantitative MRI and proton MR spectroscopic imaging.

The effects of chronic cocaine and alcohol abuse on human brain structure and metabolites are not fully known. We studied controls (n = 13) and abstinent subjects dependent on cocaine (8), alcohol (12), and cocaine and alcohol (17) using quantitative MRI and proton MR spectroscopic imaging. Talairach-based techniques yielded tissue and CSF volumes and gray- and white-matter concentrations of N-acetylaspartate (NAA), creatine and choline metabolites in multiple brain regions. Alcohol dependents had lower gray-matter NAA concentrations and more sulcal CSF than non-alcohol dependents throughout the brain. They also had less subcortical gray matter and (regionally) less white matter. Cocaine dependents compared with non-cocaine dependents had higher posterior parietal white-matter creatine concentration. They also had less gray and white matter in the prefrontal lobes and in a region encompassing the temporal lobes and cerebellum. Structural white-matter deficits in cocaine dependents were greater with longer duration of cocaine use. Subjects with concurrent cocaine and alcohol dependence had less prefrontal white matter, especially in the anterior cingulate, than subjects dependent on only one substance. Chronically abused cocaine and alcohol each leave multiple metabolic and structural brain defects after long-term abstinence. Concurrent dependence on both substances may aggravate white-matter structural defects, primarily in frontal brain.

Journal Article↗