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PubMed1997

Atrophy of the cerebellum and brainstem in dentatorubral pallidoluysian atrophy. Influence of CAG repeat size on MRI findings.

To elucidate how the size of the expanded CAG repeat of the gene for dentatorubral pallidoluysian atrophy (DRPLA) and other factors affect the atrophy of the brainstem and cerebellum, and the appearance of high-intensity signals on T2-weighted MRI of the cerebral white matter of patients with DRPLA, we quantitatively analyzed the MRI findings of 26 patients with DRPLA, the diagnosis of which was confirmed by molecular analysis of the DRPLA gene. When we classified the patients into two groups based on the size of the expanded CAG repeat of the DRPLA gene (group 1, number of CAG repeat units > or = 66; group 2, number of CAG repeat units < or = 65), we found strong inverse correlations between the age at MRI and the areas of midsagittal structures of the cerebellum and brainstem in group 1 but not in group 2. Multiple regression analysis, however, revealed that both the patient's age at MRI and the size of the expanded CAG repeat correlated with the areas of midsagittal structures. Involvement of the cerebral white matter as detected on T2-weighted images was observed more frequently in patients belonging to group 2 than in group 1 patients. Furthermore it was demonstrated that high-intensity signals can be detected on T2-weighted images of the cerebral white matter of patients with a largely expanded CAG repeat (group 1) in their thirties. These results suggest that patient age as well as the size of the expanded CAG repeat are related to the degree of atrophy of the brainstem and cerebellum, and the white matter changes in patients with DRPLA.

Adolescent↗

PubMedDate not supplied

Extraperitoneal pelvic leiomyosarcoma. MR findings in a case.

The magnetic resonance imaging (MRI) of a patient with nongynecologic pelvic leiomyosarcoma is presented. A retroperitoneal mass appeared under the broad ligaments, in the right paravesical and parametrial, lateral pararectal site. The mass leaned on the uterus and vagina. On MRI, the mass had solid structure, isointense on T1-weighted images, inhomogeneously iperintense on T2-weighted images with central areas of increased intensity. Late after contrast agent administration, the mass appeared inhomogeneously ipointense with areas of fair late contrast enhancement. The morphology of the tumor, the retroperitoneal site, and MRI sequences make the differential diagnosis. These evidences were useful in treatment planning.

Combined Modality Therapy↗

PubMed1984

Magnetic resonance imaging of aortic disease: preliminary results.

Fourteen patients with a variety of aortic diseases were evaluated with magnetic resonance imaging (MRI). These included abdominal aortic aneurysms (eight cases), aortoiliac aneurysm (one), thoracoabdominal aneurysm (one), aortic dissections (four), and Takayasu arteritis (one). The size and extent of aneurysms, the presence of thrombus or atherosclerotic debris, the relation to renal and iliac arteries, and the effect of aneurysms on adjacent structures were readily demonstrated by MRI. The size of the residual lumen in a variety of vascular diseases and abnormal blood flow patterns could be assessed. In aortic dissection, MRI permitted identification of intimal flaps and determination of the origin of aortic branches from either of two lumina. Thickening of the wall and luminal narrowing of the aorta and arch vessels in Takayasu arteritis were clearly defined. These early results indicated that MRI achieved precise and complete assessment of a number of aortic abnormalities without the administration of any type of contrast material. Thus, early experience suggests that an important application of MRI will be as a totally noninvasive and reliable method for evaluating aortic disease.

Adult↗

PubMed1999

Postoperative evaluation of congenital heart disease by magnetic resonance imaging.

In the last four decades the survival of patients with corrected or palliated congenital heart disease has increased dramatically. However, post-operative abnormalities frequently occur and therefore a noninvasive imaging tool is mandatory for the timely detection of morphological as well as functional abnormalities. Magnetic resonance imaging (MRI) is ideally suited for the noninvasive diagnosis and post-operative follow-up of congenital heart disease. Spin-echo MRI is able to visualize structures that may be difficult to assess with other noninvasive image modalities and is sensitive in the detection of post-interventional stenoses or aneurysms. Because the function of the ventricles may deteriorate over time after correction or palliation of a congenital cardiac malformation, the use of gradient-echo MRI is essential in the follow-up after correction or palliation, as no other conventional technique allows such detailed evaluation of ventricular function, without geometrical assumptions. Phase-contrast MRI is well suited to assess valvular function, allowing accurate measurement of regurgitation or stenosis. Shunt quantification is another application of phase-contrast MRI. J. Magn. Reson. Imaging 1999;10:656-666.

Follow-Up Studies↗

PubMed2025

A computational ontology framework for the synthesis of multi-level pathology reports from brain MRI scans.

BackgroundConvolutional neural network (CNN) based volumetry of MRI data can help differentiate Alzheimer's disease (AD) and the behavioral variant of frontotemporal dementia (bvFTD) as causes of cognitive decline and dementia. However, existing CNN-based MRI volumetry tools lack a structured hierarchical representation of brain anatomy, which would allow for aggregating regional pathological information and automated computational inference.ObjectiveDevelop a computational ontology pipeline for quantifying hierarchical pathological abnormalities and visualize summary charts for brain atrophy findings, aiding differential diagnosis.MethodsUsing FastSurfer, we segmented brain regions and measured volume and cortical thickness from MRI scans pooled across multiple cohorts (N = 3433; ADNI, AIBL, DELCODE, DESCRIBE, EDSD, and NIFD), including healthy controls, prodromal and clinical AD cases, and bvFTD cases. Employing the Web Ontology Language (OWL), we built a semantic model encoding hierarchical anatomical information. Additionally, we created summary visualizations based on sunburst plots for visual inspection of the information stored in the ontology.ResultsOur computational framework dynamically estimated and aggregated regional pathological deviations across different levels of neuroanatomy abstraction. The disease similarity index derived from the volumetric and cortical thickness deviations achieved an AUC of 0.88 for separating AD and bvFTD, which was also reflected by distinct atrophy profile visualizations.ConclusionsThe proposed automated pipeline facilitates visual comparison of atrophy profiles across various disease types and stages. It provides a generalizable computational framework for summarizing pathologic findings, potentially enhancing the physicians' ability to evaluate brain pathologies robustly and interpretably.

Humans↗

PubMed1996

Obesity in childhood craniopharyngioma: relation to post-operative hypothalamic damage shown by magnetic resonance imaging.

OBJECTIVE: To quantify the extent of hypothalamic damage after surgery for craniopharyngioma using magnetic resonance imaging (MRI) and to relate the findings to changes in body mass index (BMI). PATIENTS: Sixty-three survivors (36 males, 27 females) of childhood cramopharyngioma were treated surgically between 1973 and early 1994. METHODS: Cranial MRI was performed at a structured follow-up assessment 1.5-19.2 yr after the initial surgery. Hypothalamic damage was scored as 0 (no visible damage), 1 (intermediate), or 2 (severe). RESULTS: After surgery there was an increase in BMI standard deviation (SD) from diagnosis to study assessment in all but 7 patients. However, patients with MRI scores of 2 (n = 17) had a significantly greater increase in median BMI SD score at follow-up (+5.5 SD score), compared with +2.5 SD score and +1.1 SD score for patients with MRI scores of 1 or 0, respectively. Of the 17 cases with MRI scores of 2, 10 had a history of extreme weight loss or weight gain at presentation; preoperative neuroimaging demonstrated extensive hypothalamic infiltration by tumor in these cases. CONCLUSION: MRI gives sufficient anatomical definition to allow assessment of the extent of hypothalamic damage and, thereby, prediction of the patients most at risk for severe post-operative weight gain.

Adolescent↗

PubMed2005

Design, synthesis, physical and chemical characterisation, and biological interactions of lectin-targeted latex nanoparticles bearing Gd-DTPA chelates: an exploration of magnetic resonance molecular imaging (MRMI).

The physical and chemical parameters involved in the design and synthesis of biospecifically targeted nanoparticulate contrast media for magnetic resonance molecular imaging (MRMI) were explored in this pilot investigation. Latex nanoparticles 100, 400 and 900 nm in diameter were doubly derivatised, first with tomato lectin and then with gadolinium(III)-diethylenetriamine pentaacetic acid (Gd-chelates) to target them to epithelial and endothelial glycocalyceal N-glycans and to generate contrast enhancement in magnetic resonance imaging (MRI). After intravenous injection into mice, human placental cotyledons or human Vena saphena magna, contrasty images of the vascular structures were obtained in 1.5 T MRI with spatial resolution 0.1 mm in the imaging plane and 0.6 mm in the z axis, persisting >60 min and resistant to washing out by buffer rinses. Ultrastructural analysis of the nanoparticles revealed the targeting groups at the nanoparticle surfaces and the distribution of the Gd-chelates within the nanoparticles and enabled counts for use in determining relaxivity. The relaxivity values revealed were extremely high, accounting for the strong MR signals observed. Occasionally, nanoparticles larger than 100 nm were seen in close spatial association with disrupted regions of cell membrane or of collagen fibrils in the extracellular matrix. The data suggest that 100-nm nanoparticles generate adequate contrast for MRMI and cause least disruption to endothelial cell surfaces.

Animals↗

PubMed2000

MRI and ultrasound in children with juvenile chronic arthritis.

In this era of advancing imaging technology, a knowledge of the relative values of available imaging techniques is necessary to optimize the management of children with juvenile chronic arthritis (JCA). After clinical examination, plain films remain the initial investigation. The need for radiation protection must be a priority in children with JCA. Conventional radiographs allow grouping of the various arthritides (on the base of the distribution and pattern of joint space changes) and staging of disease progression. Ultrasound (US) is very sensitive in the detection of joint effusions, especially in the hip, and guides fluid aspiration. US and Doppler can be used for the evaluation of synovial hypertrophy and activity. Arthrography and to a certain extent nuclear studies have been replaced by magnetic resonance imaging (MRI). MRI can demonstrate articular cartilage, joint effusion, synovial hypertrophy, cortical and medullary bone, cartilage and bone perfusion, and fibrocartilaginous structures (menisci and ligaments). Contrast enhanced MRI is the most sensitive modality to determine whether an arthritic condition is present. However, it does not assist in establishing a specific diagnosis. MRI determines accurately the activity and the extent of the disease and is particularly useful in the early detection of articular damage. Finally, MRI is of major importance in the evaluation of response to local therapy (especially steroids) and the detection of complications.

Arthritis, Juvenile↗

PubMed2003

Magnetic resonance imaging and immunoblot analyses in rats with experimentally induced cerebral alveolar echinococcosis.

The early stage of experimentally induced secondary cerebral alveolar echinococcosis (AE) in rats was investigated by use of magnetic resonance imaging (MRI) and immunoblot (western blot) analyses. Thirty-six female Wistar rats (6 to 8 weeks old) were injected intracranially with a 10% homogenate of echinococcal larval tissues in which the concentrations of microvesicles and protoscolices were estimated to be 3.8 and 1.5 x 10(4)/ml, respectively. To observe the fine structure of the rat brain, MRI was performed under a high magnetic field of 7.05 T. Histologic examination also was performed. The T2-weighted MR images revealed a hyperintense region in the cerebral cortex at two weeks after injection of the homogenate. At three weeks after injection, this region was found to have cysts on the basis of results of histologic examination. Signal-void regions corresponding to hyperplasia and the subsequent calcification of the cuticle layer at six and 13 weeks after injection, respectively, were observed in T2-weighted and proton density MR images. On the other hand, at nine weeks after injection, AE was discernible by use of western blot analysis of sera with antibodies of two epitopes (Em18 and Em16) of E. multilocularis. Using this secondary cerebral AE animal model, it was concluded that the MRI method was suitable for early detection of secondary cerebral AE.

Animals↗

PubMed1985

MRI of the heart, mediastinum and great vessels.

MRI permits to study the anatomical structures of the heart and great vessels without cardiac catheterization or contrast injections. It aims to differentiate trachea and bronchia from the mediastinal lymph nodes. In mediastinal tumours, MRI supplies essential information for the planning of therapy. Only in the area of the structures adjacent to the diaphragm, an improvement of the images by means of additional respiratory gating is desirable.

Blood Vessels↗

PubMed1988

A review of applications of MRI in soft tissue and bone tumors.

Due to excellent soft tissue contrast and multiplanar imaging capability, MRI is assuming a major role in recognition, staging, and treatment planning of soft tissue and bone tumors. Direct sagittal, coronal, and axial images permit assessment of intraosseous and extraosseous extension of tumors and their relationship to the joints and neurovascular structures, and detection of "skip" lesions. MRI allows improved detection of recurrent tumors in the presence of non-ferromagnetic metallic implants as compared to CT. In the evaluation of soft tissue tumors, MRI is more sensitive than CT and allows differentiation among fat, muscle, tendon, bone, and vascular structures based on signal characteristics. Over a period of 18 months, 100 soft tissue masses and bone tumors were evaluated using MRI. Spin echo sequences with T1 and T2 weighted images were most valuable in differentiating normal and abnormal tissues. Calculated comparative measurements of relaxation times showed no reliable difference between benign and malignant tumors.

Adolescent↗

PubMed2000

Neuroimaging correlates of cognitive and functional outcome after traumatic brain injury.

Magnetic resonance imaging (MRI) may provide an estimate of the severity of diffuse axonal injury by quantitative measurements of atrophy of white matter tracts (such as corpus callosum) and of ventricular enlargement (particularly the third ventricle). However, most MRI studies failed to reveal consistent relationships between the pattern of neuropsychological impairments and the site and extent of focal structural lesions after traumatic brain injury. Functional neuroimaging techniques, such as positron emission tomography or functional MRI, may reveal areas of cerebral dysfunction in regions that look structurally intact on MRI. Studies using these techniques have suggested that the cognitive and behavioural disturbances of traumatic brain injury could be related to a defective activation of a prefrontal-cingulate network.

Animals↗

PubMed1991

[Cine magnetic resonance imaging for evaluating flow dynamics in congenital heart diseases with left-to-right shunts].

Cine magnetic resonance imaging (cine MRI) was used to evaluate the cardiac structures and blood flow in congenital heart diseases with left-to-right shunts. Fifteen children with left-to-right shunts which were confirmed by echocardiography or angiography were investigated in the present study. Five children each had atrial septal defect, ventricular septal defect, and complete endocardial cushion defect. Their ages ranged from 4 months to 13 years (mean 5.5 years). Prior to cine MRI, the ECG-gated cardiac imaging using multi-slice acquisition was performed in all the children to localize the optimal slice for cine MRI. To select the optimal imaging planes for various cardiac structures, we used axial, coronal, sagittal and four-chamber views. Cine MRI was demonstrated by a fast low 30 degree flip angle imaging technique, with a 15 msec echo time, a 30-40 msec pulse repetition time, and a 256 x 256 or 128 x 128 acquisition matrix. Abnormalities of cardiac structures were defined extremely well in all the children using ECG-gated cardiac imaging. In 14 of the 15 children (93%), cine MRI clearly detected a left-to-right shunt flow, which was visualized as a low signal intensity area compared to the surrounding blood flow. Noninvasively, cine MRI provides accurate images of the anatomy of the cardiac structures, makes functional assessments of the cardiac chambers and walls, and flow relationships. It has no limitations of imaging planes imposed bones and lung, and is not associated with technical difficulties as required with echocardiography which has small cardiac window.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1995

Schizophrenia--a brain disease? A critical review of structural and functional cerebral abnormality in the disorder.

BACKGROUND: With genetic and neurochemical findings pointing to a biological aetiology, considerable effort has been devoted to finding direct evidence of brain abnormality in schizophrenia. METHOD: CT, MRI, post-mortem and functional imaging studies are reviewed to assess which structural and/or functional brain abnormalities have been consistently demonstrated. RESULTS: The only well-established structural abnormality in schizophrenia is lateral ventricular enlargement; this is modest and there is a large overlap with the normal population. There is no consensus on the presence of any localised structural abnormality from MRI and post-mortem studies, but the most promising findings concern temporal lobe limbic structures. Hypofrontality is not a well-replicated finding in schizophrenia under resting conditions, but the evidence is stronger for a selective association with negative symptoms. A number of studies have found hypofrontality under conditions of neuropsychological task activation. However, findings in these studies are divided and a recent methodologically sophisticated study has failed to confirm it, although this study suggested a decoupling of prefrontal and temporal function. CONCLUSION: Schizophrenia is characterised by minor structural abnormality which, in the case of lateral ventricular enlargement, may be better understood as a risk factor than a causative lesion. The functional imaging findings are not transparent but suggest that, as a disorder, schizophrenia shows complex alterations in regional patterns of activity rather than any simple deficit in prefrontal function.

Brain↗

PubMed2003

Evidence for cortical functional changes in patients with migraine and white matter abnormalities on conventional and diffusion tensor magnetic resonance imaging.

BACKGROUND: In this study, we used functional MRI (fMRI) to investigate the pattern of cortical activations after a simple motor task in patients with migraine and white matter (WM) abnormalities on conventional MRI scans of the brain. We also investigated whether the extent of brain activations was correlated with WM structural pathology measured using diffusion tensor (DT) MRI. METHODS: From 15 right-handed patients with migraine and 15 sex- and age-matched, right-handed healthy volunteers, we obtained the following: (1) fMRI (repetitive flexion-extension of the last 4 fingers of the right hand), (2) dual-echo turbo spin echo scans, and (3) pulsed-gradient spin-echo echo-planar sequence to calculate DT-MRI maps. fMRI analysis was performed using SPM99 and cluster detection. We measured the volume, the average mean diffusivity (), and the average fractional anisotropy of all lesions seen on the dual-echo scans. histograms of the normal-appearing WM were also produced. RESULTS: Compared with healthy volunteers, migraine patients had a larger relative activation of the contralateral primary sensorimotor cortex (P=0.01) and a rostral displacement of the supplementary motor area (P=0.03). The shapes of the curves reflecting the time course for fMRI signal intensity changes were similar between migraine patients and controls for all of the cortical areas we studied. Compared with healthy subjects, migraine patients had significantly lower histogram peak height of the normal-appearing WM histogram (P=0.02), which was found to be correlated with the extent of displacement of the supplementary motor area (r=-0.80, P<0.001). CONCLUSIONS: This study suggests that functional cortical changes occur in patients with migraine and brain MRI abnormalities and that they might be secondary to the extent of subcortical structural damage.

Adolescent↗

PubMed1992

Quantitative changes in mesial temporal volume, regional cerebral blood flow, and cognition in Alzheimer's disease.

Twenty-six patients with moderately severe Alzheimer's disease (AD) and 16 normal control subjects were studied using either quantitative magnetic resonance imaging (MRI) measures of mesial temporal atrophy (15 patients with AD and 16 normal control subjects) and/or quantitative radioactive iodine 123-N-isopropyl-iodoamphetamine single-photon emission computed tomography (SPECT) assessment of regional cerebral blood flow (20 patients with AD and eight normal control subjects). Nine individuals with AD and eight normal control subjects underwent both structural and functional imaging. On MRI, patients and controls were best discriminated using left amygdala and entorhinal cortex volumes, and on SPECT they were best discriminated by relative left temporoparietal cortex blood flow. Combining these MRI and SPECT measures yielded 100% discrimination. Relative left temporoparietal SPECT regional cerebral blood flow and left superior temporal gyral MRI volume correlated best with severity of cognitive deficit in patients with AD. Mesial temporal MRI atrophy exceeded generalized cerebral shrinkage. Both SPECT and MRI regional changes accorded with areas known to be affected by AD neuropathology.

Aged↗

PubMed1991

[Clinical features and imaging findings of posterior cerebral artery infarction].

The clinical features and imaging findings of posterior cerebral artery infarction (PCAI) in 18 cases verified by CT scan and/or MRI, DSA, SPECT were reported, and their interrelation were analyzed. It was found that the main clinical feature of PCAI was visual defect with amnesia syndrome, the lesion was predominant in the right hemisphere. In examining the structure and function of brain and vessels, each of CT, MRI, ECT and DSA had its own advantage and might complement the others, CT and MRI were better in displaying the structure of cerebral parenchyma than ECT and DSA, whereas, MRI was superior in distinguishing the lesions in deep white matter and subtentorial region. DSA was better than MRI and CT in displaying vascular structure, but was inferior in disclosing the occlusion of deep perforating branches or cortical arterioles. ECT, besides its ability to show the morphological changes of brain, was mainly used to disclose the functional changes of cerebral parenchyma, being a method to make early diagnosis for CVD. However, ECT was inferior than MRI and CT, in displaying lacunar infarction and lesions of brain-stem.

Adult↗

PubMed1992

MRI or CT in the preoperative diagnosis of bone tumours.

The value of magnetic resonance imaging (MRI) and computed tomography (CT) in the diagnosis of bone tumours was investigated in a prospective study of 25 patients. MRI is superior to CT because it permits multidirectional exposures. Moreover, the tumour can be readily distinguished from the neurovascular structures without injection of contrast medium. MRI gives better contrast than CT, making it possible to study the relationship to the soft tissues, bone marrow and joints more accurately. On the other hand, CT gives a better picture of the destruction of cortical bone. With neither MRI nor CT can the exact tumour length be measured. Neither MRI nor CT permits an exact, reliable diagnosis. Owing to the relatively slow exposure technique in combination with respiratory movements, depiction of the thoracic wall is less satisfactory with MRI than with CT. If both techniques are available, MRI is preferred. In view of the fact that MRI apparatus is still less widely available, it should be borne in mind that CT also allows an adequate investigation of skeletal lesions.

Adolescent↗