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Results for “Structural MRI”

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At least 685 records · Page 38Linked to original sources
PubMed1997

Simulation of soft-tissue tumor excisions: a multimodal interactive approach.

Total 3-D reconstruction of the tumor size, shape, and relations with surrounding structures using CT, MRI, sonography, and angiography images can make simulated radical resection of soft-tissue sarcomas possible, thus sparing normal tissues. With our approach, starting from three MR images for a given patient, a new single image representation of all three parameters is generated by using two different techniques on a workstation in a standard UNIX and X-11 environment. The first one is a transformation linking together the MR parameters and the RGB (red, green, blue) color components. The second one is an unsupervised segmentation method based on a number of neural and fuzzy models. We can dinamically render and update a stereo display using field sequential presentation of left and right eye views on the monitor, with Cristal Eyes LCD shutter eyewear (StereoGraphics Inc., San Rafael, CA) to view it. As 3D locating tool, a 3D locating control system based on low-frequency magnetic fields (Polhemus Fastrak) has been chosen. Simulations of soft-tissues excisions may be performed in this interactive environment with augmented-reality modalities. All this, in our experience, has greatly facilitated the simulation of soft-tissue sarcoma excisions.

Artificial Intelligence↗
PubMed1999

Balance disturbances in individuals with vibroacoustic disease.

INTRODUCTION: In previous studies, patients with vibroacoustic disease (VAD) presented hyperintense foci in T2 of the cerebral white matter, brainstem and basal nuclei. The most probable etiology is ischemia. One of the most frequent complaints of these patients is balance disturbances which, in two cases, has threatened the patients' ability to maintain their jobs. The purpose of this study was to compare two methods, one neurophysiological (auditory evoked potentials - AEP) and the other structural imaging (brain MRI), in order to determine to what extent the changes detected with these methods may be related to each other in this pathology. METHODS: Twenty individuals occupationally exposed to large pressure amplitude (> or = 90 dB SPL) and low frequency (< or = 500 Hz) noise, received neurological and otorhinolaryngological examinations. All of them had previously received audiograms, tympanograms and electronystagmograms. All 20 patients also received brain MRI and AEP studies. RESULTS: The individuals with vertigo and changes of the AEP present the greater number of changes in the brain MRI. CONCLUSION: This could be an indication that in many VAD cases vertigo may have a central origin.

Adult↗
PubMed1999

[Two cases of thoracic aneurysm with aberrant origin of the aortic branches: diagnosis and strategy].

We present two cases of thoracic aortic aneurysms with anomalous origin of the aortic arch branches. One was a 72-year-old female with a ruptured descending thoracic aneurysm and aberrant origin of the right subclavian artery. The other was a 64-year-old male with a saccular distal arch aneurysm and aberrant origin of the left vertebral artery. Preoperative examinations included angiography, computed tomography (CT), three dimensional enhanced CT (3DCT), digital subtraction angiography (DSA), and magnetic resonance imaging (MRI). Understanding the structure of neck vessels is important in deciding where to clamp or to reconstruct in surgical repair of the aortic arch. 3DCT was the most useful examination for this understanding.

Aged↗
PubMedDate not supplied

[Diagnosis of rheumatoid arthritis of knee joints using magnetic resonance imaging].

A combination of clinical, X-Ray and magnetic resonance tomographic studies for 129 knee joints was made in 85 patients with rheumatoid arthritis of knee joints. MRI symptoms of rheumatoid arthritis of knee joints, including fluid accumulation in the articular cavity, degeneration of the articular cartilage, meniscus, ligaments, proliferation of the synovial membrane, destructive changes in osseous epiphysis were defined. Comparative analysis of the X-Ray and MRI imaging findings has shown that MRI has advantages structures of joints in rheumatoid arthritis.

Adult↗
PubMed1999

Transcranial magnetic stimulation--a new tool for functional imaging of the brain.

Recent progress in the theory and technology of transcranial magnetic stimulation (TMS) is leading to novel approaches in brain mapping. TMS becomes a powerful functional brain mapping tool when other imaging methods are used to record TMS-evoked activity or when peripheral effects are observed as a function of stimulus location. TMS-evoked activity currently can be recorded by EEG, PET, and fMRI. In addition to providing indices of cortical excitability, these methods allow one to study brain connectivity directly, without the need for behavioral activations. When the coordinate systems in the different imaging modalities are combined, anatomical structures seen in MRI and activation sites determined by PET, fMRI, or MEG/EEG can be used for the selection of target areas in the brain. PET and fMRI can be used to map the spatial distribution of TMS-evoked activity. On the other hand, the combination of TMS and high-resolution EEG may often be the method of choice for basic neuroscience and for clinical diagnosis, for example, in the assessment of brain connectivity in patients suffering from neurodegenerative diseases or head injuries.

Brain↗
PubMed2000

[MR arthrography].

Review article on MR arthrography: technique and main indications. Intra-articular injection of diluted Gadolinium provides good distension and better appreciation of intra-articular structures than standard MRI. It is useful for partial tears of the rotator cuff, in cases of gleno-humeral instability, lesions of the acetabular labrum and hyaline articular cartilage and also for elbow, wrist and ankle ligamentous ruptures.

Acetabulum↗
PubMed2002

[Repair of focal chondral lesions of femoral condyles treated with osteochondral autografts].

A series of 15 patients with focal chondral lesions of the femoral condyles were treated at the Orthopaedics Department of the University of Medical Sciences of Lublin between 1998-2000. The patients' age varied from 20 to 72 years and the follow-up period from 6 months to 2.5 years. Osteochondritis dissecans was observed in 9 patients. Articular cartilage defects associated with chronic ligament instability was noted in 5 cases and 1 patient suffered from a chondral fracture of the lateral femoral condyle during a traumatic luxation of the patella. The depth of the lesions was graded according to ICRS scale. Grade IV was found in 11 cases and the remaining 4 cases had grade III lesions. The defects were treated with osteochondral autografts using OATS instrumentation set. Results were prospectively evaluated according to the HSS score. The preoperative value of HSS score ranged from 28 to 51 points (average 40.3). During follow-up the score values ranged from 76 to 91 points (average 84.7 points). All patients regained full range of motion in the knee, although in one case arthroscopic release of intraarticular adhesions was performed 6 months after chondroplasty. The lowest HSS values at follow-up were found in elderly patients with concomitant mild degenerative changes in the lateral knee compartment and in the patello-femoral joint. All patients had MRI examination early post-op, then after 6, 12 and 24 months from the procedure. MRI confirmed proper structure of the grafted cartilage but bony parts of the graft did not integrate with the surroundings.

Adult↗
PubMed2005

MRI and neurological findings in macrocephaly-cutis marmorata telangiectatica congenita syndrome: report of ten cases and review of the literature.

MRI and neurological findings in macrocephaly-cutis marmorata telangiectatica congenita syndrome: report of ten cases and review of the literature: We describe the clinical history and magnetic resonance imaging (MRI) findings in 10 children with the Macrocephaly-Cutis Marmorata Telangiectatica Congenita syndrome (M-CMTC--MIM 602501). This syndrome has recently been delineated within the general group of patients with Cutis Marmorata Telangiectatica (CMTC) as a distinct and easily recognisable entity. In contrast to most children with CMTC, patients with M-CMTC syndrome have a high risk of neurological abnormalities, such as hydrocephalus, megalencephaly, developmental delay and mental retardation. An MRI scan showed structural cerebral abnormalities in all of our patients, including megalencephaly, asymmetry of the cerebral hemispheres and abnormally increased signal of white matter. Seven patients also had Chiari type I malformation. Reviewing all reported cases, we propose appropriate surveillance for known complications.

Abnormalities, Multiple↗
PubMed2006

[Epilepsy with electrical status epilepticus during slow sleep: diagnostic criteria and approaches to therapy].

Fourteen patients, aged from 5 to 14 years, with syndrome of electrical status epilepticus during slow sleep (ESESS) have been studied. The absence of epileptic attacks was observed in 21.5% of patients and diagnosis was established by a combination of continuous diffuse epileptiform activity with marked cognitive disturbances. In 78.5% patients, epileptic attacks presented as follows: pharyngeal and oral, hemicephalgia (100% patients with attacks), hemiclonic (18%), atypical absences (27%), negative myoclonus (18%), automotor (18%), focal adverse with vomiting (18%), secondary generalized (36%). Drugs of choice were valproate (depakine) and topamax in patients with attacks; suxilep and frisium in the absence of attacks and in case of continuous diffuse epileptiform activity on the sleep EEG. Two variants have been singled out by the character of ESESS syndrome. The first one, a "symptom variant", was featured by mostly hemiclonic, secondary generalized and automotor epileptic attacks, presence of continuous regional or lateral, less frequent diffuse epileptiform activity, detected by the local structural lesions in MRI, marked cognitive disturbances persisting after stopping of the attacks. The second ("idiopathic") variant is characterized by normal development of children before attack manifestation, appearance of mostly "rolandic" attacks, atypical absences and negative myoclonus, presence of exclusively continuous diffuse epileptiform activity in the phase of slow sleep, standard MRI results (moderate cortical subatrophy in single cases), cessation or substantial decrease of cognitive disturbances after attack stopping. It is emphasized that prognosis of ESESS syndrome should be considered separately with regard to attacks and cognitive disturbances. A prognosis for attacks is always favorable. Cognitive disturbances despite the therapy can persist for a long time.

Adolescent↗
PubMed2006

[Unusual localization of spinal hydatid cyst].

We report one case of uncommon spinal hydatid cysts particular by its localization. It is intradural, localized with predilection in the big cistem cerebello-medullar. There is no involvement of adjacent vertebral discs and ligaments. We specify characteristic imaging features and polymorphism of this affection who can affect all anatomical structures. We emphasize MRI for diagnosis and follow-up in search for residual or recurrent lesions.

Adult↗
PubMed2006

Reduced hippocampal volume correlates with executive dysfunctioning in major depression.

OBJECTIVE: Dysfunction of neuronal plasticity or remodelling seems to contribute to the pathopysiology of major depression and may cause the well-documented hippocampal changes in depression. We aimed to investigate whether reduced hippocampal volumes correlate with executive dysfunctioning or memory dysfunctioning or with depression severity. METHODS: We recruited 34 inpatients with a previous or current episode of major depression from the department of psychiatry at the Ludwig-Maximilians University of Munich, Germany. We examined the 34 patients and 34 healthy control subjects with structural high resolution MRI. We assessed cognitive functions with the Wisconsin Card Sorting Test (WCST) and the Rey Auditory Verbal Learning Test (RAVLT) and severity of depression with the Hamilton Depression Rating Scale. RESULTS: Hippocampal volumes and frontal lobe volumes were significantly smaller in patients, compared with healthy control subjects. Furthermore, lower hippocampal volumes were correlated with poorer performance in the WCST. No significant correlations were found between hippocampal volumes and RAVLT performance or severity of depression. CONCLUSIONS: The present findings emphasize that patients with reduced hippocampal volumes show more executive dysfunctions than their counterparts. Thus, the mechanisms resulting in reduced hippocampal volumes seem to be related to the development of major depression.

Adult↗
PubMed1989

Amyloid ophthalmoplegia. Ophthalmoparesis secondary to primary systemic amyloidosis.

We report a patient with primary systemic amyloidosis and orbital involvement associated with ophthalmoparesis. We support this with the first demonstration of eye movement recordings and magnetic resonance imaging (MRI) of such a patient. The patient presented with a restrictive ophthalmoparesis. Eye movement recordings documented slowed horizontal saccades. MRI of orbital structures suggests that all extraocular muscles were enlarged, with possible involvement of their tendinous insertions.

Amyloidosis↗
PubMed1995

[MRI in cardiology: clinical applications and perspectives].

MRI is an effective tool in the evaluation of cardiovascular diseases. With continued improvements in MR angiography, velocity mapping, myocardial tagging, imaging speed and display, it is anticipated that MRI will play an ever-increasing role in the morphological evaluation of many cardiovascular anomalies. The need for quantification in cardiology has led to the development of a variety of techniques to assess cardiac size and function. In attempting to answer these clinical questions, MRI provides major advantages several: extraordinary flexibility, powerful contrast mechanisms, sensitivity to flow and motion, and freedom from ionizing radiation, contrast agent and acoustic windows. Because of accurate initial results in quantifying cardiac chamber size, global and segmental function, it is likely that MRI methods will play an increasing role in the evaluation of cardiac structure and function. Recently, MRI has emerged as an important tool in the evaluation of great vessel disease, particularly in the evaluation of both congenital and acquired abnormalities of the aorta. Early evidence suggests that magnetic resonance may help in distinguishing constrictive pericarditis from restrictive cardiomyopathy (e.g., amyloid heart disease). Cardiac-MRI lends itself to assessment of intracardiac masses. Spin-echo imaging alone is often sufficient for diagnosis. Cine-MRI has important additive value, however, when a mass lesion shows dynamic motion, or when abnormal flow patterns in conjunction with a mass lesion require evaluation.

Echocardiography↗
PubMed1996

[Clinical imaging in psychiatry].

Brain imaging has made surprisingly remarkable progress since the early, and now historic days, of invasive radiology, which has now been replaced with a number of spectacularly precise techniques: structural (CT Scan, MRI) and functional (PET, SPECT) imaging, direct imaging during neurosurgery, EEG and its computer-assisted derivatives, and transcerebral ultrasonography. We present five cases with two alleged autisms, a cerebral malaria, a panic disorder and to Parkinson disease with a depressive component. Using modern imaging methods the following respective diagnoses were arrived at: a left temporal cyst, a Sanfilippo mucopolysaccharidosis, a septum lucidum agenesis, a right temporal cyst, and a pituitary adenoma. These cases illustrate the scientific, emotional and philosophical impact, on physicians, and patients alike, of modern imaging technology. Neuroradiology, biochemistry and surgical imaging require a multi disciplinary approach and a perfect knowledge of psychiatric semeiology. In addition, they stimulate us to carefully reassess our sociocultural understanding to mental illness.

Adenoma↗
PubMed2000

Hippocampus and entorhinal cortex in frontotemporal dementia and Alzheimer's disease: a morphometric MRI study.

BACKGROUND: Magnetic resonance imaging (MRI) of hippocampal atrophy is a sensitive but not specific method to support the clinical diagnosis of early Alzheimer's disease (AD). We recently described our findings that atrophy of the entorhinal cortex (ERC) in frontotemporal dementia (FTD) is equal to that found in AD but that hippocampal atrophy in FTD is less than that found in AD. The MRI volumes of these structures provide a topographic representation of the region of interest. We hypothesized that two different dementias with distinct histopathologic and clinical features might, in addition to quantitative patterns, display topographically different patterns of atrophy. METHODS: We adopted a morphometric approach to monitor the pattern of atrophy of the hippocampus and the ERC by computing two-dimensional profiles from MRI volumes of the structures in control subjects and patients with FTD and AD. RESULTS: Compared with control subjects, atrophy of the hippocampus in patients with AD was diffuse. In patients with FTD, atrophy of the hippocampus was localized predominantly in the anterior hippocampus, suggesting a different pattern of hippocampal atrophy in FTD compared with AD. The amount and pattern of atrophy of the entorhinal cortex was virtually equal in both demented groups. CONCLUSIONS: This study provides novel data on the nature of medial temporal lobe atrophy in FTD. Morphometric MRI may be a useful technique for characterizing different patterns of atrophy in primary degenerative dementias in vivo.

Aged↗
PubMed2006

Deformation-based mapping of volume change from serial brain MRI in the presence of local tissue contrast change.

This paper is motivated by the analysis of serial structural magnetic resonance imaging (MRI) data of the brain to map patterns of local tissue volume loss or gain over time, using registration-based deformation tensor morphometry. Specifically, we address the important confound of local tissue contrast changes which can be induced by neurodegenerative or neurodevelopmental processes. These not only modify apparent tissue volume, but also modify tissue integrity and its resulting MRI contrast parameters. In order to address this confound we derive an approach to the voxel-wise optimization of regional mutual information (RMI) and use this to drive a viscous fluid deformation model between images in a symmetric registration process. A quantitative evaluation of the method when compared to earlier approaches is included using both synthetic data and clinical imaging data. Results show a significant reduction in errors when tissue contrast changes locally between acquisitions. Finally, examples of applying the technique to map different patterns of atrophy rate in different neurodegenerative conditions is included.

Algorithms↗
PubMedDate not supplied

[A neuropsychological study of triplets with a history of prematurity].

INTRODUCTION AND AIMS: Prematurity has often been associated with a general intellectual deficit and with different structural brain disorders which can be revealed by volumetric measurements performed by magnetic resonance imaging (MRI). In turn, perinatal asphyxia, even when it is not accompanied by neurological disorders, is related to a deficit in specific neuropsychological functions. CASE REPORT: This study describes the case of three 13 year old female triplets, with a history of extreme prematurity and perinatal asphyxia, the long term effects of which are evaluated in terms of cognitive performance. We studied their performance in the neuropsychological functions of intelligence, memory, and visual perceptual, visual constructive, visual spatial and frontal functions. In two of the subjects, structural MRI and volumetric analysis of the hippocampuses were performed. In all the subjects, intelligence was found to be above average, the most notable result being the superior score in case 1. Verbal learning and the long term retention of verbal material were altered in case 3, where there was also a smaller hippocampal volume. CONCLUSIONS: In the context of a multiple birth, we have seen that extreme prematurity, accompanied by non severe perinatal asphyxia without hypoxic ischemic encephalopathy, can exert very diverse effects on neurocognitive development. It can be normal, and even superior, or show a deficit in some skill. In our case, the functions that were most liable to suffer these antecedents are long term memory and verbal learning. This disorder is accompanied by bilateral involvement of the hippocampus, which can be observed using MRI.

Adolescent↗