Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Structural MRI”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 487 records · Page 27Linked to original sources
PubMed2000

Normal cognitive performance in patients with chronic alcoholism in contrast to patients with Korsakoff's syndrome.

This study investigated which cognitive deficits are associated with chronic alcoholism. Neuropsychological profiles and MRI brain structure volumes of 14 patients with Korsakoff's syndrome, 15 patients with chronic alcoholism, and 16 healthy control subjects were compared. The patients with alcoholism had a normal cognitive performance and normal brain structure volumes. The patients with Korsakoff's syndrome had performance deficits on tests of memory, visuoperceptual, and executive functions, as well as reduced brain structure volumes. The results suggest that the cognitive deficits cannot be ascribed to mere chronic consumption of alcohol. If cognitive deficits are present in patients with chronic alcoholism, this may point to an underlying brain disorder.

Adult↗
PubMed1997

A neuropsychological perspective on three schizophrenic patients with midline structural defects.

BACKGROUND: The relationship between midline structural defects and schizophrenia remains unclear, although a number of neuroradiological studies have reported an association between schizophrenia and a range of anomalies. METHOD: Three patients are reported, each diagnosed with schizophrenia and neuroradiological evidence of midline structural anomalies. MRI scans are reported in conjunction with performance over a range of neuropsychological tests designed to assess frontal and lateralised cognitive functions. RESULTS: Evidence of anterior dysfunction was present in all three cases, while on an individual basis patients displayed varying patterns of preserved and dysfunctional cognitive processing. CONCLUSION: The reported findings raise a number of interesting issues regarding the nature of hemispheric involvement in schizophrenia.

Adult↗
PubMed2006

Older adults with cognitive complaints show brain atrophy similar to that of amnestic MCI.

OBJECTIVE: To examine the neural basis of cognitive complaints in healthy older adults in the absence of memory impairment and to determine whether there are medial temporal lobe (MTL) gray matter (GM) changes as reported in Alzheimer disease (AD) and amnestic mild cognitive impairment (MCI). METHODS: Participants were 40 euthymic individuals with cognitive complaints (CCs) who had normal neuropsychological test performance. The authors compared their structural brain MRI scans to those of 40 patients with amnestic MCI and 40 healthy controls (HCs) using voxel-based morphometry and hippocampal volume analysis. RESULTS: The CC and MCI groups showed similar patterns of decreased GM relative to the HC group on whole brain analysis, with differences evident in the MTL, frontotemporal, and other neocortical regions. The degree of GM loss was associated with extent of both memory complaints and performance deficits. Manually segmented hippocampal volumes, adjusted for age and intracranial volume, were significantly reduced only in the MCI group, with the CC group showing an intermediate level. CONCLUSIONS: Cognitive complaints in older adults may indicate underlying neurodegenerative changes even when unaccompanied by deficits on formal testing. The cognitive complaint group may represent a pre-mild cognitive impairment stage and may provide an earlier therapeutic opportunity than mild cognitive impairment. MRI analysis approaches incorporating signal intensity may have greater sensitivity in early preclinical stages than volumetric methods.

Aged↗
PubMed2003

Coregistration of diffuse optical spectroscopy and magnetic resonance imaging in a rat tumor model.

We report coregistration of near-infrared diffuse optical spectroscopy (DOS) and magnetic resonance imaging (MRI) for the study of animal model tumors. A combined broadband steady-state and frequency-domain apparatus was used to determine tissue oxyhemoglobin, deoxyhemoglobin, and water concentration locally in tumors. Simultaneous MRI coregistration provided structural (T2-weighted) and contrast-enhanced images of the tumor that were correlated with the optical measurements. By use of Monte Carlo simulations, the optically sampled volume was superimposed on the MR images, showing precisely which tissue structure was probed optically. DOS and MRI coregistration measurements were performed on seven rats over 20 days and were separated into three tumor tissue classifications: viable, edematous, and necrotic. A ratio of water concentration to total hemoglobin concentration, as measured optically, was performed for each tissue type and showed values for edematous tissue to be greater than viable tissue (1.2 +/- 0.49 M/microM versus 0.48 +/- 0.15 M/microM). Tissue hemoglobin oxygen saturation (StO2) also showed a large variation between tissue types: viable tissue had an optically measured StO2 value of 61 +/- 5%, whereas StO2 determined for necrotic tissue was 43 +/- 6%.

Adenocarcinoma↗
PubMed2006

Tibialis anterior tendon and extensor retinaculum: imaging in cadavers and patients with tendon tear.

OBJECTIVE: Under the hypothesis that the anatomic relationship of the tibialis anterior tendon and extensor retinaculum of the foot and ankle is relevant to the clinical aspects of a tear in that tendon, we assessed the anatomic details of these structures using MRI in cadavers and evaluated MRI in patients with a tibialis anterior tendon tear. MATERIALS AND METHODS: Seven cadaveric feet underwent detailed MRI using standard and oblique coronal planes with respect to the course of the tibialis anterior tendon and extensor retinaculum. Cadaveric sections subsequently provided an anatomic correlation. MR images of seven patients with tibialis anterior tendon tear were analyzed by consensus of two musculoskeletal radiologists. RESULTS: Imaging-anatomic correlations allowed identification of the tibialis anterior tendon and extensor retinaculum. The tendon passed through three tunnels formed by the superior extensor retinaculum, oblique superomedial, and oblique inferomedial limbs of the inferior extensor retinaculum. Of seven patients with the tendon tear, three patients had complete tears and four patients had partial tears. In all partial tears, the level of the tear was at the ankle joint, corresponding to the approximate level of the oblique superomedial limb. In all complete tears, the proximal ends of torn tendons were retracted to a level below the oblique superomedial limb. In all tears, the oblique superomedial limb surrounding the torn tendon was seen with thickening in four patients and enhancement after IV gadolinium injection in two patients. Other findings included a bulbous appearance or swelling of the torn tendon in two complete and two partial tears and fluid collections within the tendon sheath and in an area confined by the extensor retinaculum in four patients. CONCLUSION: The relationship of the tibialis anterior tendon and extensor retinaculum is well depicted on MRI, even in patients with a tibialis anterior tendon tear, and is clinically relevant to the tear of this tendon.

Adult↗
PubMed2002

[Volumetric measurements of the hippocampus and amygdala with MRI in healthy adults].

INTRODUCTION: Volumetric analysis of brain magnetic resonance images (MRI) measures structural changes associated with neurological and neuropsychiatric disorders. In recent years several studies have shown the utility of the volumetric measurement of the medial temporal lobe structures, especially the amygdala and the hippocampus in temporal lobe epilepsy, memory disorders, Alzheimer disease and schizophrenia. AIM: The purpose of this study was to measure and establish our normal values of the hippocampus and amygdala volumes. METHODS: All studies were performed using a 1.0 T Siemens unit with FISP 3D sequence. One millimeter, contiguous coronal scans of 40 healthy volunteers aged 19-26 years were obtained. The regions of interest were outlined using a mouse driven cursor. To determine the anatomic boundaries of the hippocampus and the amygdala the authors followed a generally accepted protocol previously described by C. Watson. RESULTS: The mean right and left hippocampal volumes were 2.12 cm3 (SD = 0.31) and 2.07 cm3 (SD = 0.3) and the mean right and left amygdaloid volume were 1.19 cm3 (SD = 0.19) and 1.2 cm3 (SD = 0.2) respectively. The mean asymmetry between the right and left hippocampus and amygdala was 3.17% and 3.48%, respectively. The inter-observer reliability range (alpha) was between 0.97 and 0.77. Subregional analysis of hippocampus was calculated as well. CONCLUSIONS: Normal volumetric data measured in our study fell in the midrange of the values in the literature. The volumetric analysis of the hippocampal subregions may allow assessment of providing more sensitive determination of the atrophic area, which may be important in epileptic disorders.

Adult↗
PubMed2005

October 2004: a 49-year-old man with progressive dementia.

October 2004. A 49-year-old right-handed man developed progressive cognitive difficulties over a 4-month period. There was impairment in recent memory, calculations and language. He also developed fatigue, weight loss, gait imbalance and urinary incontinence. Past history included transfusion-associated Hepatitis C. Neurologic exam showed mild dysarthria, dysnomia, left sided neglect, bilateral Babinski signs, and a prominent grasp reflex. Laboratory testing provided no positive etiologic data. An EEG showed generalized intermittent slowing suggestive of a diffuse encephalopathy and decreased background in the right hemisphere, suggestive of a structural lesion. MRI showed multiple areas of high signal on FLAIR imaging and patchy enhancement. FDG-PET showed multi-focal areas of increased uptake, correlating with the abnormal areas on MRI, on a background of decreased uptake. A 4-vessel cerebral angiogram showed no abnormalities. A brain biopsy showed diffuse infiltrates of large malignant cells that were immunoreactive with antibodies to CD20, diagnostic of diffuse large B cell lymphoma. In summary, the clinical presentation suggested bilateral hemispheric involvement, which was supported by physical examination, EEG, MRI, and PET scans. The differential diagnosis for this presentation is limited to demyelinating disease such as multiple sclerosis, vascular dementia, and infiltrating neoplasm such as glioblastoma multiforme or lymphoma. Diagnosis was made by morphologic and immunohistochemical analysis of brain tissue.

Brain Neoplasms↗
PubMedDate not supplied

[Ankylosing spondylitis--the current situation and new therapeutic options].

Ankylosing spondylitis (AS) is a chronic, immunologically mediated rheumatic disease whose progression largely depends on the extent of inflammatory activity. In contrast to rheumatoid arthritis (RA), therapeutic control of AS is very limited. Therapy of ankylosing spondylitis should not only control inflammatory processes, but also prevent structural damages and maintain the functions. Until recently, physiotherapy and non-steroidal antiphlogistics (NSA) therapy was a gold standard of AS treatment. NSA therapy alleviates inflammatory pain of spine in 60 to 80% of patients. According to the most recent findings, long-term administration of NSA can affect also X-ray progression. DMARD therapy, which is efficient in RA, has insignificant effect on axial form of AS. Sulfasalazine proved to be efficacious against peripheral form of AS; administration of MTX and leflunomide is not supported by controlled studies. Peripheral arthritis and enthesitis is usually treated by short-term application of corticoids. The fact remains that an important role in AS immunopathogenesis is played by TNF alpha whose increased levels were found in patients with AS in serum, synovial fluid and SI joints. Anti-TNF therapy with infliximab and etanercept proved to be highly efficacious in patients with AS resistant to conventional therapy. Infliximab and etanercept reduced the disease activity (50% improvement in more than half of patients), improved the function and slowed down the structural damage. MRI studies of anti-TNF therapy proved reduction of inflammatory activity in SI joints and spine. Other studies verified the efficacy of adalimumab in AS therapy and showed that adalimumab is a promising drug. Also, several randomized clinical studies proved efficacy of thalidomide whose administration, however, is limited by its severe adverse effects. Until now, the results of studies focused on pamidronate therapy appear to be rather controversial. Better understanding of AS pathogenesis led to implementation of new therapeutic procedures that significantly improve activity and functional condition of patients.

Antibodies, Monoclonal↗
PubMed1995

Evaluation for surgical treatment of partial epilepsy: an overview.

When a focal epilepsy proves refractory to medical therapy, surgical treatment is available and increasingly used. Most interventions consist of focal cortical resections, and by far the most common operation is a temporal lobectomy. The presurgical evaluation is complex and multidisciplinary. It includes clinical evaluation, EEG-video monitoring, neuropsychological testing, and structural as well as functional imaging. When surface EEG fails to identify the epileptogenic zone with sufficient confidence, several invasive methods are available, each with its advantages and limitations. In addition to neurophysiologic data, when there is convergence of structural imaging (MRI) and functional testing (Wada test, neuropsychological evaluation, nuclear imaging), a single focus can be identified, and a focal resection is likely to be successful. Surgery is a well-accepted and effective therapeutic modality for patients with refractory epilepsy. When surgical candidates are selected appropriately, results are excellent, especially for temporal lobe epilepsy.

Electroencephalography↗
PubMed2006

Structural and functional plasticity in the somatosensory cortex of chronic stroke patients.

Animal studies have demonstrated that motor recovery after hemiparetic stroke is associated with functional and structural brain plasticity. While studies in stroke patients have revealed functional plasticity in sensorimotor cortical areas in association with motor recovery, corresponding structural plasticity has not been shown. We sought to test the hypothesis that chronic hemiparetic stroke patients exhibit structural plasticity in the same sensorimotor cortical areas that exhibit functional plasticity. Functional MRI during unilateral tactile stimulation and structural MRI was conducted in chronic stroke patients and normal subjects. Using recently developed computational methods for high-resolution analysis of MRI data, we evaluated for between-group differences in functional activation responses, and cortical thickness of areas that showed an enhanced activation response in the patients. We found a significant (P < 0.005) increase in the activation response in areas of the ventral postcentral gyrus (POG) in the patients relative to controls. These same ventral POG areas showed a significant (P < 0.05) increase in cortical thickness in the patients. Control cortical areas did not show a significant between-group difference in thickness or activation response. These results provide the first evidence of structural plasticity co-localized with areas exhibiting functional plasticity in the human brain after stroke.

Adult↗
PubMed2001

MRI of the hypothalamus and pituitary gland in patients with hyperprolactinaemia following radiotherapy for nasopharyngeal carcinoma.

PURPOSE: Neuroendocrine dysfunction is a known complication of cranial radiation. While growth hormone deficiency is the most common laboratory finding, hyperprolactinaemia is one of the most common symptomatic dysfunction in adult female patients with nasopharyngeal carcinoma (NPC) following radiotherapy. This analysis aims to study the magnetic resonance imaging (MRI) features of the hypothalamus and the pituitary gland in affected patients. METHODS: MRI was performed in 24 patients NPC with hyperprolactinaemia detected 10-52 months following one course of radical radiotherapy. The region of study included the nasopharynx, the hypothalamus and the pituitary gland in 20 patients, while in the remaining four patients, this was limited to the pituitary gland. The estimated radiation dose to the hypothalamus and the pituitary gland was 66 Gy, and six patients also had adjuvant chemotherapy. There was no clinical evidence of tumour recurrence in all 24 patients when hyperprolactinaemia was detected. RESULTS: None of the 24 patients showed any MRI evidence of structural abnormality in the hypothalamic-pituitary region. CONCLUSION: MRI did not reveal any structural abnormality in the hypothalamic-pituitary region of patients who developed hyperprolactinaemia following radiotherapy for NPC.

Adult↗
PubMed2004

Structural changes in the midbrain with aging and Parkinson's disease: an MRI study.

We measured midbrain structures of 59 subjects with Parkinson's disease (PD) and 140 age- and gender-matched normal subjects without neurological disorders by using T2-weighted MR imaging. There is a significant increase in the maximum distance of the substantia nigra (SND) and a significant decrease in the average distance from the substantia nigra to the red nucleus (SNRND) in patients with PD compared with normal subjects in the 70 years old or less group. These findings may reflect the pathologic increase of iron concentration and the neuronal loss in the region. However, it is difficult to find differences between normal subjects and patients with PD in the greater than 70 years old group in the midbrain structures. These findings based on a large-scale morphometric study provide essential information to evaluate conventional MR images of PD.

Adult↗
PubMed2004

The structural adaptations in compressed articular cartilage by microscopic MRI (microMRI) T(2) anisotropy.

OBJECTIVES: To detect structural adaptations of collagen fiber matrix in compressed articular cartilage in individual sub-tissue zones by microscopic magnetic resonance imaging (microMRI) at 23 microm in-depth resolution. DESIGN: Each of the six beagle humeral cartilage specimens was placed in a specially built nonmetallic compression device inside an in-situ rotation device, and was imaged four times at 7T: without and during static compression, and at two orientations: 0 degrees and 55 degrees . Proton intensity images and quantitative T(2) maps were constructed and analyzed. RESULTS: Upon compression at 55 degrees (the magic angle), rather than appearing homogenous, T(2)-weighted intensity images of cartilage showed a distinct laminar appearance and the T(2) profiles exhibited two distinctive peaks. At both 0 degrees and 55 degrees orientations, lower values of T(2) were observed in compressed tissue. A significant correlation was established between changes in tissue T(2) at 55 degrees and a thickness reduction due to compression. At a mean of 20% strain value, modifications in cartilage structure were studied at each histological zone. We found that the percentage of superficial zone was significantly doubled, the percentage of radial zone was significantly decreased by 10%, and no significant change in the transitional zone. CONCLUSIONS: External loading can induce a new kind of laminar appearance at the magic angle. microMRI T(2) anisotropy can be used to analyze the zone-specific alterations in collagen fibril organization in articular cartilage in response to mechanical compression.

Adaptation, Physiological↗
PubMed1999

Abnormal cerebral structure in juvenile myoclonic epilepsy demonstrated with voxel-based analysis of MRI.

MRI scans of patients with idiopathic generalized epilepsy (IGE) are normal on visual assessment. Using an interactive anatomical segmentation technique and volume-of-interest measurements of MRI, we showed recently that patients with IGE had significantly larger cortical grey matter than control subjects. Further, 40% of individual patients with juvenile myoclonic epilepsy (JME), a syndrome of IGE in adolescence, had significant abnormalities of cerebral structure. In this study, we applied the automated and objective technique of statistical parametric mapping (SPM) to the analysis of structural MRI from 20 patients with JME and 30 control subjects. The cortical grey matter of each individual JME patient and the group of JME patients was contrasted with that of the group of 30 normal subjects. The voxel-based SPM comparison between the group of JME patients and the control subjects showed an increase in cortical grey matter in the mesial frontal lobes of the patients. Analysis of individual patients revealed significant abnormalities of cortical grey matter in five out of 20 JME patients, four of whom had been shown to have widespread abnormalities using the previous volume of interest technique. These findings indicate a structural cerebral abnormality in JME, with involvement of mesiofrontal cortical structures.

Adolescent↗
PubMed1998

Autosomal dominant cerebellar ataxia type I. MRI-based volumetry of posterior fossa structures and basal ganglia in spinocerebellar ataxia types 1, 2 and 3.

Twenty-six patients suffering from autosomal dominant cerebellar ataxia type I were subjected to a genotype-phenotype correlation analysis using molecular genetic assignment to the genetic loci for spinocerebellar ataxia type 1, 2 or 3 (SCA1, SCA2, SCA3) and MRI-based volumetry of posterior fossa structures and basal ganglia nuclei. There was significant atrophy of the cerebellum and brainstem in all three SCA mutations compared with a group of 31 age- and sex-matched controls. Comparison between the SCA groups showed that cerebellar and brainstem atrophy was more severe in SCA2 than in SCA1 and SCA3. Putaminal and caudate volume was reduced only in SCA3, but not in SCA1 and SCA2. A set of three morphological criteria was defined that enabled us to assign all SCA2 and SCA3 patients correctly to the underlying genotype. In contrast, these criteria did not distinguish SCA1 from SCA2 and SCA3. Regression analysis failed to reveal a significant association between CAG repeat length and the volumes of the respective brain structures in any of the SCA mutant types. The present data provide in vivo evidence that SCA2 and SCA3 lead to distinct patterns of brain atrophy, while the atrophy changes in SCA1 overlap with both SCA2 and SCA3.

Adult↗
PubMed1998

[Medial collateral ligament of the knee and its surroundings: MRI findings of normal and abnormal structures].

Normal and abnormal structures of the medial corner of the knee were evaluated with coronal and axial MR images. MRI revealed 35 medial collateral ligament (MCL) tears and 61 medial meniscus (MM) tears in 200 consecutive examinations. Just under the MCL, little or no fluid retention was identified between the superficial and deep layers of the MCL or between the MM and MCL in normal knees and in cases of MM tears. At the anterior aspect of the MCL, the deep layer merges with the capsule of the suprapatellar bursa, potentially leaving space for fluid retention. Fluid collection posterior to the MCL was demonstrated in a few cases. Fluid retention with edematous swelling just under the MCL was noted in the cases of MCL tears. MM-MCL distances in the cases of normal structure, MM tears and MCL tears were 2.1 mm, 2.7 mm and 4.7 mm, respectively. The deep layer of the MCL, which was enhanced by the presence of joint fluid, was identified in 71% of cases.

Adult↗
PubMed2006

Abnormalities of thalamic activation and cognition in schizophrenia.

OBJECTIVE: Functional and structural magnetic resonance imaging (MRI) was used to investigate relationships among structure, functional activation, and cognitive deficits related to the thalamus in individuals with schizophrenia and healthy comparison subjects. METHOD: Thirty-six schizophrenia subjects and 28 healthy comparison subjects matched by age, gender, race, and parental socioeconomic status underwent structural and functional MRI while performing a series of memory tasks, including an N-back task (working memory), intentional memorization of a series of pictures or words (episodic encoding), and a yes/no recognition task. Functional activation magnitudes in seven regions of interest within the thalamic complex, as defined by anatomical and functional criteria, were computed for each group. RESULTS: Participants with schizophrenia exhibited decreased activation within the whole thalamus, the anterior nuclei, and the medial dorsal nucleus. These nuclei overlap with subregions of the thalamic surface that the authors previously reported to exhibit morphological abnormalities in schizophrenia. However, there were no significant correlations between specific dimensions of thalamic shape variation (i.e., eigenvectors) and the activation patterns within thalamic regions of interest. Better performance on the working memory task among individuals with schizophrenia was significantly associated with increased activation in the anterior nuclei, the centromedian nucleus, the pulvinar, and the ventrolateral nuclei. CONCLUSIONS: These results suggest that there are limited relationships between morphological and functional abnormalities of the thalamus in schizophrenia subjects and highlight the importance of investigating relationships between brain structure and function.

Adult↗
PubMed2000

MRI-based measurements of temporal lobe and ventricular structures in patients with bipolar I and bipolar II disorders.

OBJECTIVE: There have been relatively few quantitative MRI studies of temporal lobe structures and the lateral ventricles in bipolar patients and a lack of agreement across studies as to whether these structures differ significantly in size from control subjects. Also there have been no quantitative MRI studies of bipolar II patients. The present study measured temporal lobe and ventricular structures in both bipolar I and bipolar II patients, as well as control subjects. METHOD: Twenty-five bipolar I patients, 22 bipolar II patients and 19 control subjects underwent MRI brain scans. The 5 mm coronal slices of each subject were coded and measured by a rater who was blind with respect to subject diagnosis. Volume estimates of the temporal lobe and hippocampus were calculated for each hemisphere by measuring the area of the structure in each slice in which it appears, multiplying by 5 mm and summing. In addition to these volume estimates, the area of the lateral ventricle and the inferior horn of the lateral ventricle, the lateral ventricle to cerebrum area ratio (LV/C) and the temporal lobe to cerebrum area ratio (TL/C), were calculated for each hemisphere in one reference slice only. The area of the third ventricle was also measured. Volume estimates and area ratios were then compared among diagnostic groups. RESULTS: There were no significant differences in temporal lobe or hippocampal volume estimates, in the third ventricle and inferior horn of the lateral ventricle area measurements, and in the TL/C area ratio among diagnostic groups. The lateral ventricle area and LV/C area ratio were significantly larger in bipolar I patients than either bipolar II patients or control subjects only in the left hemisphere. Furthermore, these measures were approximately twice as large in the bipolar I patients as the other groups. CONCLUSIONS: The current study adds to a growing literature that bipolar I disorder, particularly in males, may show different neurobiological alterations compared to bipolar II patients or control subjects. The pathophysiologic implications of this accumulating evidence of increased left ventricular size in bipolar I disorder remains to be further elucidated.

Adult↗