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PubMedDate not supplied

[Central cancer of the lung in MR image].

The paper analyzes the authors' own material based on the data of chest magnetic resonance imaging (MRI) in 48 patients with verified central cancer of the lung. The algorithm of chest MRI optimized by the authors is presented. The MRI signs of lung cancer in exo- and peribronchial forms of cancer are systematized. The MRI semiotics of chest structural damages are given in the extent of a tumor when progressing, and a metastatic lesion. The MRI signs of complications of this disease are specified.

Adult↗
PubMed2005

[MRI diagnosis of neurodegenerative disorders].

Routine use of high field MRI has greatly contributed to the clinical diagnosis of neurodegenerative disorders, because MRI enables to visualize degenerative process showing either atrophy of the specific areas or degeneration of specific structures. Among many specific MRI signs which have been hitherto proposed to be diagnostic for certain neurodegenerative disorders, the author discussed here some clinically useful ones with neuropathological interpretations. "Humming-bird sign" is highly diagnostic for progressive supranuclear palsy (PSP) because it represents focal atrophy of the rostro-dorsal portion of mid-brain tegmentum where the neural centers for vertical gaze specifically affected in PSP are located. Un-treated Wilson disease patients show frequently "face of giant panda sign" of mid-brain which disappears after successful treatment. Although the sign is pathognomonic for Wilson disease, neuropathological entity of this MRI abnormality has not been known yet. MRI enables to discriminate two types of cerebellar atrophies; cerebellipetal atrophy in which ponto-, spino- and olivo-cerebellar fibers are lost, and cerebellofugal atrophy in which loss of Purkinje cells is the main pathological process. In cerebellipetal atrophy, cerebellar white matter shows T2 high signal due to the degeneration of nerve fibers in it but T2 low signal of dentate nucleus is usually well preserved. This combination of degenerative process realized" black teeth sign" of dentate nucleus in MRI. On the other hand, cerbellofugal atrophy shows "white teeth sign" of dentate nucleus, because the loss of Purkinje cell axons causes signal change of dentate nucleus where the axons of Purkinje cells are concentrating. "White teeth sign" could also be observed in case of the degeneration of dentate nucleus itself, like in DRPLA, but differential diagnosis between Purkinje cell loss and dentate degeneration is not so difficult, because the atrophy of the superior cerebellar peduncle is detectable in the latter but never seen in the former condition.

Brain↗
PubMed2002

Description of a poorly differentiated carcinoma within the brainstem of a white whale (Delphinapterus leucas) from magnetic resonance images and histological analysis.

In this study we used magnetic resonance imaging (MRI) to investigate neuroanatomical structure in the brain of a white whale (Delphinapterus leucas) that died from a large tumor within the brainstem. This specimen was also compared with a normal white whale brain using MRI. MRI scans of the white whale specimen show how the tumor deformed surrounding brain structure. Histopathological analysis indicated a poorly differentiated carcinoma of uncertain origin. These analyses demonstrate the usefulness of supplementing histological analyses of pathology with studies of gross morphology facilitated by MRI.

Animals↗
PubMed2002

Regional changes in brain gray and white matter in patients with schizophrenia demonstrated with voxel-based analysis of MRI.

This study examined regional structural changes in the whole brain in 45 medicated patients with schizophrenia (23 males and 22 females), comparing with 42 age- and sex-matched healthy volunteers (22 males and 20 females). Automated voxel-based analysis on three-dimensional magnetic resonance imaging (MRI) was conducted using statistical parametric mapping (SPM). Compared with the controls, relative gray matter in the patients was significantly reduced in the left superior temporal, left middle and inferior frontal, right inferior frontal, and bilateral anterior cingulate and medial temporal areas. Gray matter reductions in the left superior temporal and prefrontal areas were found predominantly in the male patients, while the anterior cingulate gray mater reduction was more striking in the female patients. On the contrary, significant gray matter increases in the patients were found in the parietal areas and the cerebellum. In the white matter, significant reduction was found in the bilateral anterior limbs of the internal capsule and the superior occipitofrontal fasciculus, whereas the bilateral parietal white matter showed significant increases. These results suggest that a pathological process in schizophrenia predominantly affects the fronto-temporolimbic-paralimbic regions. Reduced white matter in the connecting bundles, which was first found in this study, may imply morphological substrates for abnormalities in the fronto-thalamic and fronto-temporolimbic connectivity in schizophrenia.

Adolescent↗
PubMed2003

Severity of cervical spine ligamentous injury correlates with mechanism of injury, not with severity of blunt head trauma.

Clearance of the cervical spine (CS) in obtunded trauma patients in an intensive care unit is problematic. Patients with no osseous injuries have potential unstable extradural supportive soft tissue injury. Evaluation of the supporting structures involves dynamic fluoroscopy or MRI both of which have inherent risks and convenience issues. Defining which of these patients are at highest risk for severe supportive structure injury may improve resource utilization for CS clearance. The purpose of this study was to evaluate clinical factors that may predict the probability of CS supportive soft tissue injury in patients with traumatic brain injury. Patients who sustained traumatic brain injury with intracranial pathology, absence of CS osseous injury, and a limited cervical spine MRI within 72 hours of injury were included. Potential clinical predictors included the severity of the traumatic brain injury defined by the Abbreviated Injury Severity Score for the cerebrum and initial Glasgow Coma Scale, the Injury Severity Score (ISS), mechanism of injury, and high versus low-velocity mechanism. Severity of soft tissue/ligament injury was graded by MRI findings. One hundred twenty-five patients met the study criteria; 81 had negative MRI findings and in 44 the MRI study was positive for potentially unstable injuries. High-velocity mechanisms of injury and ISS--not the severity of the traumatic brain injury or initial Glasgow Coma Scale score--were statistically significant predictors of severe CS supportive soft tissue injuries. Obtunded blunt trauma patients who have been involved in high-velocity-mechanism incidents and have high ISS are at greatest risk for extradural supportive soft tissue CS injuries. These patients should either remain in CS immobilization until clinical evaluation can be completed or undergo further evaluation of their supportive soft tissue structures by MRI or fluoroscopic flexion/extension.

Adult↗
PubMed1995

High-resolution magnetic resonance imaging of the endolymphatic duct and sac.

An anatomical study was carried out to determine the extent to which magnetic resonance imaging (MRI) could delineate inner ear structures. Anatomical preparations of human petrous temporal bone were examined and compared with the results of MRI in 20 healthy subjects to see whether the structures of the inner ear could be visualized. Imaging of the subjects was carried out in a 1.0-T MRI scanner (Siemens Magnetom Impact). Two strongly T2*-weighted sequences were used: a 3D-PSIF sequence and a 3D-CISS sequence. The 3D data sets were postprocessed using a Maximum Intensity Projection (MIP) program. Our investigations show that it is possible to obtain accurate visualization of structures with a diameter of under 1 mm. In all 20 subjects it was possible to identify both the endolymphatic duct and the endolymphatic sac.

Adult↗
PubMed2004

Comparison of high-resolution MRI, optical microscopy and SEM for quantitation of trabecular architecture in the rat femur.

Magnetic resonance imaging (MRI) has been used to analyze trabecular bone architecture in femur heads taken from adult Wistar rats. The aim of this study was to validate the use of MRI in assessing trabecular structure and morphology by comparing standard measures of bone morphology in the rat femur obtained from high resolution MRI with those obtained by conventional optical microscopy and by scanning electron microscopy (SEM). MR images were obtained on a Bruker 4.7 T micro-imaging system using a three-dimensional spin echo sequence with spatial resolution of 23 microm in-plane and a slice thickness of 39 microm. Optical images were obtained by de-calcifying the bone in EDTA and then sectioning 5-microm-thick slices. SEM images were obtained from bone embedded in epoxy resin with surface preparation by diamond polishing. Values of standard bone morphological parameters were compared and correlation coefficients between the MRI and the optical- and SEM-derived measures of morphology were calculated. Partial volume effects in MRI were minimized in this study by the use of very thin slices, yielding better agreement with optical- and SEM-derived measures of trabecular bone morphology than have been obtained in previous studies. Correlations between the MRI and optical data were significantly lower than those between the MRI and SEM data. Effects of de-calcification were also investigated. The results indicate that comparison of MRI with thin (de-calcified) optical images may be inherently flawed due to the destructive de-calcification and sectioning process used to prepare samples for the optical imaging.

Animals↗
PubMed2006

Evaluation of morphological plasticity in the cerebella of basketball players with MRI.

Cerebellum is a key structure involved in motor learning and coordination. In animal models, motor skill learning increased the volume of molecular layer and the number of synapses on Purkinje cells in the cerebellar cortex. The aim of this study is to investigate whether the analogous change of cerebellar volume occurs in human population who learn specialized motor skills and practice them intensively for a long time. Magnetic resonance image (MRI)-based cerebellar volumetry was performed in basketball players and matched controls with V-works image software. Total brain volume, absolute and relative cerebellar volumes were compared between two groups. There was no significant group difference in the total brain volume, the absolute and the relative cerebellar volume. Thus we could not detect structural change in the cerebellum of this athlete group in the macroscopic level.

Adult↗
PubMed2000

Two dimensional inverse imaging (2DII) of current sources in magnetoencephalography.

A new magnetoencephalographic (MEG) technique for imaging the cortical distribution of neuronal activity is described. An iterative algorithm is employed, which successively alters an initial estimate of cortical source structure until it corresponds to the measured magnetic field data. In this new technique, the continuum of electrical activity across the cortical surface is modeled as a dense grid of thousands of single equivalent current dipoles. MEG imaging of both compact and extended sources is facilitated by a wavelet-like transformation of the source space into a sequence of successively smaller composite source structures. Two of these composite source structures are combined during each iterative step to generate an improved estimate of the cortical source structure. Thus, inversion of the complete gain matrix corresponding to thousands of cortical sources is not performed. The technique requires only moderate PC based resources even for very large source grids. In contrast to minimum norm MEG imaging methods, this new algorithm is insensitive to random noise in the data. If available, prior knowledge of source structure from other imaging techniques, such as PET, MRI and fMRI, is easily incorporated as additional constraints on the source structure solution. Source images solutions corresponding to simulated data are presented. In addition, the technique is applied to source imaging of real MEG data incorporating cortical structure from volumetric MRI data. These results demonstrate the capability of our new technique for imaging combinations of compact and extended source structures.

Algorithms↗
PubMed2005

Cortical abnormalities in bipolar disorder investigated with MRI and voxel-based morphometry.

Bipolar disorder (BD) has been associated with abnormalities of brain structure. Specifically, in vivo volumetric MRI and/or post mortem studies of BD have reported abnormalities of gray matter (GM) volume in the medial prefrontal cortex (PFC), amygdala, hippocampal subiculum and ventral striatum. These structures share anatomical connections with each other and form part of a "visceromotor" network modulating emotional behavior. Areas of the lateral orbital, superior temporal and posterior cingulate cortices project to this network, but morphometric abnormalities in these areas have not been established in BD. The current study assessed tissue volumes within these areas in BD using MRI and voxel-based morphometry (VBM). MRI images were obtained from 36 BD subjects and 65 healthy controls. To account for possible neurotrophic and neuroprotective effects of psychotropic medications, BD subjects were divided into medicated and unmedicated groups. Images were segmented into tissue compartments, which were examined on a voxel-wise basis to determine the location and extent of morphometric changes. The GM was reduced in the posterior cingulate/retrosplenial cortex and superior temporal gyrus of unmedicated BD subjects relative to medicated BD subjects and in the lateral orbital cortex of medicated BD subjects relative to controls. White matter (WM) was increased in the orbital and posterior cingulate cortices, which most likely reflected alterations in gyral morphology resulting from the reductions in the associated GM. The morphometric abnormalities in the posterior cingulate, superior temporal and lateral orbital cortices in BD support the hypothesis that the extended network of neuroanatomical structures subserving visceromotor regulation contains structural alterations in BD. Additionally, localization of morphometric abnormalities to areas known to exhibit increased metabolism in depression supports the hypothesis that repeated stress and elevated glucocorticoid secretion may result in neuroplastic changes in BD.

Adult↗
PubMed2003

[Spiral computed tomography (CT) and magnetic resonance imaging (MRI) in assessment of the skull base encroachment in nasopharyngeal carcinoma].

BACKGROUND & OBJECTIVE: With the general using of computed tomography (CT) and magnetic resonance imaging (MRI), it is important to determine which method is more sensitive in detecting the skull base encroachment in clinic. This article was designed to investigate the diagnostic value of CT and MRI in detecting the skull base erosion in nasopharyngeal carcinoma patients. METHODS: Sixty-one cases pathologically proven as nasopharyngeal carcinoma were selected from August 1993 to September 2001. three-dimensional reconstruction with spiral CT thin slices scan were performed in 8 cases. CT scan was performed with Elscient CT Twin Flash; axial scan was parallel to the OM line routinely from soft palate to the suprasellar cistern. There were 13 cases with enhancement scan. MRI scan was performed by Philips T5-II super-conducting magnetic resonance imaging system (0.5T). The standard quadrature head coil was used. Routine axial, sagittal, and coronal image with SE sequences were obtained. Scanned field ranged from the soft palate to the suprasellar cistern. After plain scan, enhanced scan was performed in 55 of 61 cases. RESULTS: MRI discovered the skull base encroached more precisely than CT, 17 cases by CT and 26 cases by MRI, respectively. The early bone marrow infiltration was seen at clivus, basilar pterygoid, and basilar sphenoid in 6 cases by MRI scan while CT scan showed no abnormal lesion at these sites. In addition, MRI revealed nasopharyngeal carcinoma tissue infiltrated along the mandibular nerve (3 cases) while CT scan showed no change of these structures. CONCLUSION: Both CT and MRI can reveal that the tumor encroaches on the skull base by either destroying the bony structure or breaking through the natural foramen. MRI is more sensitive than CT in detecting the skull base encroachment. MRI could reveal the early infiltration of the bone marrow and tumor infiltration along the mandibular nerve. MRI confirms the dimension of nasopharyngeal carcinoma more precisely than CT. The three dimension reconstructional spiral CT was directer in discovering the dimension of the tumor.

Adolescent↗
PubMed2005

Age related preservation and loss in optimized brain SPECT.

BACKGROUND: Recent single photon emission computed tomography (SPECT) studies have reported age related increases in regional brain perfusion (called preservation here) as well as losses. AIM: To apply optimized SPECT processing to better define and understand both age related preservation and loss in brain SPECT. METHODS: Brain SPECT was performed on 85 healthy subjects using Tc hexamethylpropylene amine oxime (HMPAO), processed using findings from recent optimization work, and subjected to voxel based statistical analysis. RESULTS: SPECT preservation was seen in white matter. This distribution differs from other SPECT reports, but is similar to that for preservation observed with structural magnetic resonance imaging (MRI). This suggests that SPECT preservation may arise from age related changes in brain anatomy, not regional cerebral blood flow (rCBF), and we demonstrate that it can arise from the partial-volume effect in areas where white matter contracts with age. Age related losses extended over the whole pre-frontal midline area and an extended pattern of focal losses was seen in the peripheral cortex that was consistent with major sulci. There were also focal losses in the cerebellum. The most significant SPECT loss was in the anterior cingulate, although no structural changes were observed there in the MRI study. A model of sulcal widening at the junction of the inter-hemispheric fissure and cingulate sulcus, when degraded by the partial-volume effect, could explain this anterior cingulate loss. CONCLUSION: Optimized processing has revealed spatial patterns for age related preservation and losses in brain SPECT that indicate their origin is primarily structural. Correction for structural effects in optimized SPECT is needed to confirm whether any regional ageing effects derive from changes in rCBF.

Adolescent↗
PubMed1997

[Structural magnetic resonance tomography in diagnosis and research of Alzheimer type dementia].

One of the most widely used neuroimaging procedures in Psychiatry and Neurology is magnetic resonance imaging (MRI). MRI has gained the position of a standard investigation in the differential diagnosis of dementia syndromes. In the clinical diagnosis of Alzheimer's disease (AD) MRI helps to improve the diagnostical accuracy. Recently new MRI-based techniques for performing volumetric measurement of cortical and subcortical structures have been developed. First reports indicate that MRI-based volumetric measurements can be accurate in differentiating AD patients from cognitively normal elderly individuals. These new techniques may be useful adjunct in assessing the clinical diagnosis of AD. Results could also yield insight in the fundamental pathology of the degenerative disease. It is the objective of this chapter to summarize and comment on the significance of MRI in the diagnosis and research of AD. Future directions are outlined, including the use of microscopic MRI, the differentiation of white matter signal hyperintensities and the combined evaluation of structural MRI and functional imaging techniques.

Adult↗
PubMed2002

Convulsive status epilepticus in children with intractable epilepsy is frequently focal in origin.

BACKGROUND: Convulsive status epilepticus (CSE) is a common neurological emergency. Our objectives were to study children with recurrent nonfebrile CSE to assess the evidence for focal origin. METHODS: Series of 18 children with recurrent CSE and intractable epilepsy were identified by chart review. Clinical, radiological, and EEG data were reviewed. Focal structural abnormalities were identified on MRI and CT images by one neuroradiologist who was unaware of the clinical details. RESULTS: The patient's ages ranged between 6-22 years (mean 15.3, SD 4), and 67% were males. Most children (89%) had a severe cognitive and / or behavioural disorder. Most patients (89%) had multiple seizure types and 95% of these were partial seizures. Twelve (67%) children had at least one episode of CSE with focal features identified clinically. Focal brain abnormalities were detected on 18% and 55% of CT and MRI films respectively. Overall, 53% had a focal abnormality on structural neuroimaging. Interictal EEG revealed focal or multifocal abnormalities on at least one occasion in 94% and 22% of patients respectively. Overall, 17 patients had focal features on at least one EEG. Thirteen ictal EEGs were recorded on 11 (61%) patients. Ten (91%) of these recordings revealed a focal onset. CONCLUSIONS: Many handicapped children with recurrent CSE have focal clinical, radiological, or electrographic features. This supports a focal origin for CSE in most children with intractable epilepsy.

Adolescent↗
PubMed2005

Methodological issues relating to in vivo cortical myelography using MRI.

The relationship between neocortical structure and function is a key area of research in neuroscience. Most studies of neural function, whether using neurophysiology or neuroimaging methods, are interpreted with relation to the underlying cortical myelo- and cytoarchitecture. For functional neuroimaging studies this often means using cytoarchitectonic maps based on the study of a limited number of brains, despite evidence for substantial interindividual variation. Improvements in MR technology, resulting in wider availability of high-field MRI systems, have led to an increase in the achievable resolution in MR scans. Several groups have reported the in vivo detection of myelination patterns within the cortex, consistent with those observed in postmortem tissue. This leads to the possibility of predefining areas for fMRI analysis based on the cortical architecture. To do this it is essential to know, in a quantitative way, how reliably myeloarchitectonic areas and boundaries can be detected using MRI. Here we investigate the striate cortex, known to be coincident with V1, to assess the detectability of the stria of Gennari across V1 and across subjects. Under optimal conditions, 80% of the stria of Gennari was visualized using our methodology, although there was considerable variability in the level of detection across subjects. We discuss the limitations of the methodology and propose ways to improve the detection level of cortical myeloarchitecture more generally.

Adult↗
PubMed1998

MRI of Normal Variants and Interpretation Pitfalls of the Elbow.

One of the fundamental principles of MR imaging interpretation is the ability to distinguish normal anatomical landmarks from true disease. The radiologist is thus compelled to accumulate a comprehensive knowledge of normal structures, variants, and potential MRI diagnostic pitfalls.1-5 In this article we will focus on a number of normal bony, ligamentous, and tendinous structures that can simulate disease at the elbow. We discuss the particular anatomy responsible for the appearance of each of these interpretation pitfalls as well as the distinguishing features between these normal variants and true disease.

Journal Article↗
PubMed2004

Reliability of brain volumes from multicenter MRI acquisition: a calibration study.

Multicenter studies can provide additional information over single center studies because of their increased statistical power. Because similar acquisition protocols are being used internationally for structural magnetic resonance imaging (MRI) studies of the human brain, volumetric MRI data studies seem suitable for this purpose. Possible systematic differences between sites should be avoided, however, particularly when subtle differences in tissue volume are being searched for, such as in neuropsychiatric diseases. In this calibration study, the brains of six healthy volunteers were (re)scanned with MR scanners from four different manufacturers at five different sites, using the local acquisition protocols. The images were segmented at a central reference site. The intraclass correlation coefficient (ICC) was determined for the whole brain, gray and white matter, cerebellum, and lateral and third ventricle volumes. When required, the processing algorithms were calibrated for each site. Calibration of the histogram analysis was needed for segmentation of total brain volume at one site and for gray and white matter volume at all sites. No (additional) calibration was needed for cerebellum and ventricle volumes. The ICCs were > or = 0.96 for total brain, > or = 0.92 for cerebellum, > or = 0.96 for lateral ventricle, > or = 0.21 for third ventricle, > or = 0.84 for gray matter, and > or = 0.78 for white matter volume. Calibration of segmentation procedures allows morphologic MRI data acquired at different research sites to be combined reliably in multicenter studies.

Adult↗
PubMed1991

[Magnetic resonance imaging in the diagnosis of retrotracheal pulmonary artery].

The authors report the case of a 3-month-old infant with a history of interventricular septal defect with pulmonary arterial hypertension. This child had pulmonary symptomatology (dyspnea, recurrent bronchitis, acute attacks of asphyxia) which it was possible to link to a retrotracheal left pulmonary artery by magnetic resonance imaging (MRI). Classical investigations (upper GI barium series and chest X-ray) were suggestive of a bronchogenic cyst type abnormal pulmonary structure. Angiography confirmed the MRI diagnosis. In this case the infant also had tracheal lesions (lower tracheal hypoplasia) which required further evaluation by fibroscopy and bronchography. Thus MRI shows itself to be a useful investigation in the study of basic vascular abnormalities.

Arterial Occlusive Diseases↗