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 1,657 records · Page 92Linked to original sources
PubMed2003

Reduced cortical folding in schizophrenia: an MRI morphometric study.

OBJECTIVE: Although well documented, regional brain structural abnormalities in schizophrenia are nonspecific, and morphometric parameters show significant overlapping between patients and healthy comparison subjects. An increasing number of studies have focused on supraregional models involving abnormalities of the neuronal circuitry between cortical regions in schizophrenia. The aim of the present study was to investigate cortical folding as an index of the neuronal wiring in different subtypes of schizophrenia. METHOD: Magnetic resonance imaging measures of gyrification index in intervals of 3.6 mm along the total cerebral cortex were compared in 40 patients with DSM-IV schizophrenia and 20 healthy subjects. Psychopathology was assessed with the Positive and Negative Syndrome Scale, Brief Psychiatric Rating Scale, and the Negative Symptom Rating Scale. RESULTS: The schizophrenia patients showed significantly reduced bilateral cortical folding relative to healthy comparison subjects. Such reductions were more pronounced in those with the disorganized subtype and showed an inverse correlation with negative symptoms and a positive correlation with positive symptoms. The paranoid subtype showed reduced cortical folding that was restricted to the left hemisphere. CONCLUSIONS: These results from a larger patient group confirm a previous report of reduced cortical folding in schizophrenia patients. They also suggest a distinct pattern of abnormality between schizophrenia subtypes regarding the process of cerebral lateralization and are in agreement with the neurodevelopmental hypothesis of schizophrenia.

Adult↗
PubMed1993

Cystic hygroma of the parotid gland.

Cystic hygroma of the parotid gland is an uncommon benign congenital neoplasm that presents as an asymptomatic soft fluctuant mass. Cervical ultrasonography, computerized tomography (CT) and magnetic resonance imaging (MRI) are used to assess the size and extent of the lesion and to assist in planning the surgical approach. Ultrasonography may demonstrate a multilocular cystic mass containing septa of variable thicknesses. Extension of the mass into deeper structures is more accurately assessed by CT or MRI. A CT scan may show thin-walled cystic masses filled with material of density close to that of water. The use of contrast medium can demonstrate the relationship of the lesion to the surrounding structures. Magnetic resonance imaging is superior to CT in defining the nature and extent of the lesion.

Child↗
PubMed1997

Contribution of medial versus lateral temporal-lobe structures to human odour identification.

To investigate possible distinct contributions of different temporal-lobe structures to odour identification, the University of Pennsylvania Smell Identification Test was administered monorhinally to seizure-free patients who had undergone one of three types of temporal-lobe resection practised in three different institutions for surgical treatment of epilepsy. The resections were neocorticectomy (Dublin), selective amygdalohippocampectomy (Zurich), or anterior temporal-lobe resection with encroachment on amygdala and hippocampus (Montreal). Resections, analysed from MRI scans, showed unexpected encroachment on medial structures in most patients of the neocorticectomy groups, and largest amygdala and hippocampal resections in the amygdalohippocampectomy groups. Impaired odour identification was observed in all patient groups, irrespective of surgical approach, with greatest impairment in the nostril ipsilateral to the resection. The finding of deficits in all three surgical groups suggests that damage in the anterior temporal area, perhaps in piriform cortex, is sufficient to disrupt performance on this task; it may be that function is disrupted in the medial temporal-lobe region by disconnection when the periamygdaloid area is damaged, even when amygdala and hippocampus are left intact. An alternative explanation for our results is that damage in any one of these areas disrupts a complex network involving several distinct temporal-lobe structures.

Adolescent↗
PubMed2006

2D and 3D 3-tesla magnetic resonance imaging of the double bundle structure in anterior cruciate ligament anatomy.

For anterior cruciate ligament (ACL) surgery using the anatomic approach of the double bundle concept it is helpful to describe the anteromedial (AM) and posterolateral (PL) bundle using Magnetic Resonance Imaging (MRI), since this is the most important preoperative parameter next to the physical examination. The aim of this study was to distinguish both bundles in MRI. In a prospective study we evaluated the double bundle structure in ACL anatomy with a 3-T ultra-high-field strength MR imaging of cadaver knees, which allows faster imaging times, increased resolution and increased signal-to-noise ratio. Using oblique sagittal and oblique coronal planes, we were able to distinguish the double bundle structure in each knee. The following arthroscopic evaluation of the knees confirmed our MRI findings. Our study demonstrates the possibility of distinguishing the two bundles in the native ACL with 3T MRI. Following examinations must study the value for clinical application by describing different rupture patterns of the bundles and correlating this to arthroscopy. It would be advantageous to know the rupture pattern in advance. Presurgical planning could be improved by reconstructing only the torn and preserving the intact bundle.

Adult↗
PubMed1994

Cerebral glucose metabolism in neurofibromatosis type 1 assessed with [18F]-2-fluoro-2-deoxy-D-glucose and PET.

Cerebral PET with [18F]-2-fluoro-2-deoxy-D-glucose has been performed in four patients with neurofibromatosis type 1 (NF1) to assess the relation between cerebral metabolic activity, MRI, and the presence of neurological symptoms, including seizures, as well as mental and language retardation. Widespread hypometabolism occurred in three of the patients. The lesions on MRI, which were localised in the subcortical white matter and grey structures, had normal rates of glucose metabolism. This finding suggests that the abnormalities seen on MRI are not due to defective blood supply, localised oedema, or grey matter heterotopic foci as previously hypothesised. The presence of the hypometabolic areas seems to be inconsistently related to the occurrence of seizures and is not proportional to the degree of mental impairment. This study provides evidence of a widespread cerebral hypometabolism that is not related to the presence of MRI abnormalities; conversely normal metabolism was present in the areas with an abnormal MRI signal.

Adolescent↗
PubMed2006

Central nervous system abnormalities on midline facial defects with hypertelorism detected by magnetic resonance image and computed tomography.

The aim of this study were to describe and to compare structural central nervous system (CNS) anomalies detected by magnetic resonance image (MRI) and computed tomography (CT) in individuals affected by midline facial defects with hypertelorism (MFDH) isolated or associated with multiple congenital anomalies (MCA). The investigation protocol included dysmorphological examination, skull and facial X-rays, brain CT and/or MRI. We studied 24 individuals, 12 of them had an isolated form (Group I) and the others, MCA with unknown etiology (Group II). There was no significative difference between Group I and II and the results are presented in set. In addition to the several CNS anomalies previously described, MRI (n=18) was useful for detection of neuronal migration errors. These data suggested that structural CNS anomalies and MFDH seem to have an intrinsic embryological relationship, which should be taken in account during the clinical follow-up.

Abnormalities, Multiple↗
PubMed1985

[Possibilities of diagnosing lymphoma with MR-tomography--comparison with other imaging technics].

A retrospective study of 57 patients was made to assess the potential of magnetic resonance imaging (MRI) for demonstrating malignant lymph node disease in comparison with other imaging modalities. All patients were suspected of having lymphadenopathy in cervical, mediastinal or abdominal lymph nodes. MRI was superior in differentiating tumor involved lymph nodes from surrounding structures. On the other hand this advantage was curtailed by the spatial resolution, poorer than CT. In comparison with ultrasound MRI is the better reproducible modality and is independent of patients' constitution. Additionally MRI gives a completer overview, including retrocrural and pelvic lymph nodes. In conclusion the useful routine of ultrasonography first, completed by CT will not be changed by MRI. MRI as an additional modality is only indicated to differentiate enlarged lymph nodes from vascular structures or muscles.

Adult↗
PubMed2004

[Value of MRI in the evaluation of congenital anomalies of the heart and great vessels].

Management of congenital heart diseases (CHD) frequently is a diagnostic challenge. MRI, as a complement to echocardiography, plays an important role in the non-invasive evaluation of these anomalies. MRI allows high resolution anatomical evaluation of these structures in multiple planes as well as functional evaluation. These features are helpful to further characterize extra-cardiac anomalies that may be difficult to assess at US and even angiography. MRI is thus a valuable imaging tool in the evaluation of CHD.

Angiography↗
PubMed2007

Functional potential in chronic stroke patients depends on corticospinal tract integrity.

Determining whether a person with stroke has reached their full potential for recovery is difficult. While techniques such as transcranial magnetic stimulation (TMS) and MRI have some prognostic value, their role in rehabilitation is undefined. This study used TMS and MRI to determine which factors predict functional potential, defined as an individual's capacity for further functional improvement at least 6 months following stroke. We studied 21 chronic stroke patients with upper limb impairment. The functional integrity of the corticospinal tracts (CSTs) was assessed using TMS and functional MRI. The presence or absence of motor-evoked responses (MEPs) to TMS in the affected upper limb, and the lateralization of cortical activity during affected hand use were determined. The structural integrity of the CST was assessed using MRI, and diffusion tensor imaging was used to measure the asymmetry in fractional anisotropy (FA) of the internal capsules. A multiple linear regression analysis was performed, to predict both clinical score at inception and change in clinical score for 17 patients who completed a 30 day programme of motor practice with the affected upper limb. The main findings were that in patients with MEPs, meaningful gains were still possible 3 years after stroke, although the capacity for improvement declined with time. In patients without MEPs, functional potential declines with increasing CST disruption, with no meaningful gains possible if FA asymmetry exceeds a value of 0.25. This study is the first to demonstrate the complementary nature of TMS and MRI techniques in predicting functional potential in chronic stroke patients. An algorithm is proposed for the selection of individualized rehabilitation strategies, based on the prediction of functional potential. These strategies could include neuromodulation using a range of emerging techniques, to prime the motor system for a plastic response to rehabilitation.

Adult↗
PubMed1998

MRI brain changes in subjects with Down syndrome with and without dementia.

Individuals with Down syndrome (DS), a disorder of known genetic etiology (trisomy of chromosome 21), exhibit several types of structural brain abnormalities that are detectable pathologically and by MRI. In addition, in middle age, individuals with DS develop histological and, in some cases, clinical features of Alzheimer's disease (AD). Abnormalities in MRI scans of 50 adults with DS, 11 of whom had clinical dementia, are described and compared with those of 23 cognitively normal, healthy subjects who were matched for age, sex, and race. Qualitative visual analogue scale (VAS) ratings on MRI hard copies for all subjects and computer-aided volume measures for a subsample of subjects were carried out. On VAS, subjects with DS had larger lateral ventricles, a higher frequency of posterior fossa arachnoid cysts/megacisterna magna and fewer scans rated as normal compared with controls. Quantitatively, total brain and gray-matter volumes were reduced in DS, as were the volumes of the left hippocampus and amygdala; ventricle volumes were larger. Post hoc comparisons of subjects with DS with and without dementia revealed that on VAS the former had more generalized atrophy for age, mesial temporal shrinkage, and third ventricular enlargement. Similarly, total brain, left hippocampus, and left amygdala volumes were reduced quantitatively in subjects with DS with dementia, while ventricular volumes were increased.

Adult↗
PubMed1998

Merosin-deficient congenital muscular dystrophy with severe mental retardation and normal cranial MRI: a report of two siblings.

The evidence of severe structural brain abnormalities in association with severe mental retardation is characteristic in congenital muscular dystrophy (CMD) forms other than the 'classical' form. However, it seems that the nosology of CMD is not complete yet, as we have clinical, immunohistochemical and genetic data suggesting that there are other unclassified forms. Here we report two CMD siblings from a consanguineous family with partial merosin-deficiency in muscle biopsies, severe mental retardation and normal MRI of the brain. The disease was not linked to the LAMA2 gene (6q22-23) or to Fukuyama congenital muscular dystrophy (FCMD) (9q31-33). To our knowledge, such an association may constitute a new entity within the broad clinical spectrum of CMD.

Brain↗
PubMedDate not supplied

Magnetic resonance imaging of pelvic organ prolapse.

Magnetic resonance imaging (MRI) of pelvic organ prolapse is technically feasible and has several advantages when compared with fluoroscopic cystoproctography. Organ descent and the supportive structures of the pelvic floor can be assessed with MRI. The role of MRI in evaluating patients with pelvic floor dysfunction is evolving, and there have been many developments in the past few years. The current status of MRI of pelvic organ prolapse is reviewed.

Contrast Media↗
PubMed1989

Magnetic resonance imaging of cardiac and paracardiac masses.

Magnetic resonance imaging (MRI) with ECG-gated acquisition displays the blood pool as a signal void and thereby provides high contrast differentiation between cardiovascular structures and soft-tissue masses. The role of MRI for the detection and definition of the extent of paracardiac and intracardiac masses is reviewed. The extension of mediastinal, lung, and upper abdominal tumors to the heart and pericardium is depicted favorably by MRI and this attribute is also demonstrated. It is anticipated that MRI will have an increasing role in the evaluation of primary and secondary masses of the heart and pericardium.

Electrocardiography↗
PubMed2005

Development of vocal tract length during early childhood: a magnetic resonance imaging study.

Speech development in children is predicated partly on the growth and anatomic restructuring of the vocal tract. This study examines the growth pattern of the various hard and soft tissue vocal tract structures as visualized by magnetic resonance imaging (MRI), and assesses their relational growth with vocal tract length (VTL). Measurements on lip thickness, hard- and soft-palate length, tongue length, naso-oro-pharyngeal length, mandibular length and depth, and distance of the hyoid bone and larynx from the posterior nasal spine were used from 63 pediatric cases (ages birth to 6 years and 9 months) and 12 adults. Results indicate (a) ongoing growth of all oral and pharyngeal vocal tract structures with no sexual dimorphism, and a period of accelerated growth between birth and 18 months; (b) vocal tract structure's region (oral/anterior versus pharyngeal/posterior) and orientation (horizontal versus vertical) determine its growth pattern; and (c) the relational growth of the different structures with VTL changes with development-while the increase in VTL throughout development is predominantly due to growth of pharyngeal/posterior structures, VTL is also substantially affected by the growth of oral/anterior structures during the first 18 months of life. Findings provide normative data that can be used for modeling the development of the vocal tract.

Age Factors↗
PubMed1994

[MRI of the knee joint of young soccer players. Are there early changes of the internal structures of the knee due to competitive sports?].

In a prospective study, the right knee of 21 symptom free juvenile footballers was examined by MRT (group I) and the results were compared with 12 juveniles of similar age but who did not take part in any special sporting activities (group II). A 1.5 Tesla Magnetome with an extremity coil was used. There were no abnormal changes in either group in the cruciate ligaments. The hyaline cartilage medially was about 10% thicker than laterally in both groups but in group I it was, on average, 24.8% thicker than in group II. Increased signals in the centre of the menisci were observed in 8 members of group I and two in group II. 5 of the 8 in group I, but none in group II, also showed an increase in the joint fluid.

Adolescent↗
PubMed1999

Magnetic resonance imaging of the cochlea, spiral ganglia and eighth nerve of the guinea pig.

The membranous labyrinth of the guinea pig cochlea and retrocochlear neural structures were investigated by magnetic resonance imaging (MRI) using an experimental system with a field strength of 4.7T and a single turn surface coil 25 mm in diameter, or standard resonators of 34 or 70 mm in diameter and gradient field strengths of 950 mTm and 200 mTm. High-resolution 2-D and 3-D images of 0.3-1.0 mm slice thickness were acquired by a rapid acquisition with relaxation enhancement (RARE) sequence and a standard multi-echo technique. Structural and dimensional aspects of the cochlea were resolved in vitro and in vivo down to <50 microm, showing the scala vestibule, scala media, scala tympani, spiral ganglia and the cochlear (eighth) nerve. In vivo perfusions with the gadodiamide (GdDTPA-BMA) chelate-bound paramagnetic gadolinium ion resulted in dynamic temporal enhancement of the scala vestibule and scala tympani, but did not penetrate the scala media.

Animals↗
PubMed1985

Magnetic resonance imaging of lesions of the posterior fossa and upper cervical cord in childhood.

Magnetic resonance imaging (MRI) promises to be an effective, noninvasive means of visualizing intracranial pathology. It should be especially useful in the evaluation of posterior fossa and cervical spinal cord disease of childhood; computed tomographic (CT) evaluation is frequently suboptimal in this region. MRI results are reported for 46 consecutively seen children with posterior fossa and/or cervical spinal cord disease (28 had brain malignancies; seven had congenital anomalies; three had cerebrovascular accidents). MRI was performed primarily by the partial saturation on a .12 Tesla resistive proton unit. All patients underwent concurrent CT evaluation. MRI demonstrated abnormalities in 96% of scans in patients with structural CNS disease (48 of 50). CNS malignancies were visualized in 100% (28 of 28) of children studied. MRI was especially useful in demonstrating the full extent of infiltrating gliomas and the anatomic location of other mass lesions. MRI frequently demonstrated disease to be more extensive than seen on CT. MRI was more sensitive than CT in documenting response to treatment and disease relapse in patients with infiltrating tumors. Cystic regions within tumors were poorly seen on MRI. Congenital anomalies were demonstrated in all patients evaluated and were better delineated using MRI than CT. MRI is sensitive in the evaluation of posterior fossa and cervical spinal cord disease of childhood and it has obvious advantages over CT; however, its specificity in such evaluations has yet to be proven.

Brain↗
PubMed2006

Hemispheric asymmetries in language-related pathways: a combined functional MRI and tractography study.

Functional lateralization is a feature of human brain function, most apparent in the typical left-hemisphere specialization for language. A number of anatomical and imaging studies have examined whether structural asymmetries underlie this functional lateralization. We combined functional MRI (fMRI) and diffusion-weighted imaging (DWI) with tractography to study 10 healthy right-handed subjects. Three language fMRI paradigms were used to define language-related regions in inferior frontal and superior temporal regions. A probabilistic tractography technique was then employed to delineate the connections of these functionally defined regions. We demonstrated consistent connections between Broca's and Wernicke's areas along the superior longitudinal fasciculus bilaterally but more extensive fronto-temporal connectivity on the left than the right. Both tract volumes and mean fractional anisotropy (FA) were significantly greater on the left than the right. We also demonstrated a correlation between measures of structure and function, with subjects with more lateralized fMRI activation having a more highly lateralized mean FA of their connections. These structural asymmetries are in keeping with the lateralization of language function and indicate the major structural connections underlying this function.

Adult↗