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PubMed1989

MRI studies of atherosclerotic vascular disease: structural evaluation and physiological measurements.

The widespread prevalence of atherosclerotic vascular disease has given rise to the need for a noninvasive imaging examination. Magnetic resonance imaging has been shown to allow assessment of early arterial disease non-invasively and without the use of ionising radiation. Arterial compliance, pulse wave velocity, and the pattern of flow within the aorta may all be disturbed by disease and these parameters can be measured by magnetic resonance. In addition, atheroma can be imaged directly, its size measured, its shape described, its lipid content assessed, and its effects upon vascular haemodynamics studied. Magnetic resonance imaging is thus a potential tool not only for the detection of disease but also for studying its natural history and the effects of interventions, such as the control of risk factors and of lipid lowering agents.

Aortic Diseases↗
PubMed1994

Magnetic source localization and morphological changes in temporal lobe epilepsy: comparison of MEG/EEG, ECoG and volumetric MRI in presurgical evaluation of operated patients.

Is MEG source analysis able to precisely locate the primary focal epileptic activity? 22 patients with pharmacoresistant temporal lobe epilepsy were recorded during presurgical evaluation simultaneously with multichannel MEG/EEG and invasive (subdural) electrodes to evaluate the increase of information gained by MEG concerning the localization of focal epileptic activity and lesions. With this systematic study it should become clearer how often MEG can establish a diagnostic bridge between function and morphology. In addition, MEG localization accuracy of focal epileptic activity was to be validated empirically by invasive EEG recordings and postsurgical outcome. Spikes in the MEG were used for magnetic source localization, and the result was combined with magnetic resonance imaging (MRI). All patients definitely suffered from temporal lobe epilepsy and revealed a structural abnormality in MRI. 17 patients with lesions in the temporal lobe were operated meanwhile and became markedly improved or seizure free. In 7 of 8 patients with a tumor and validated operation outcome, a very close correlation of the 3D-magnetic source localization and the border of the tumor in the brain was found (distance less than 10 mm). In 8 of 9 patients with a temporal/hippocampal atrophy and validated operation outcome, dipoles of epileptiform activity were located within the atrophic lobe.(ABSTRACT TRUNCATED AT 250 WORDS)

Brain↗
PubMed1998

Cerebral venous infarctions presenting as enhancing space-occupying lesions: MRI findings.

Cerebral venous thrombosis is an unusual form of cerebrovascular disease that may cause cerebral venous infarction (CVI). Magnetic resonance imaging (MRI) of the brain may improve the often elusive diagnosis of CVI. However, the sensitivity, specificity, and full spectrum of such MRI findings are poorly understood. The authors present the cases of three patients with CVI whose MRI scans showed abnormally enhancing tumor-like brain lesions. Two of the CVIs were hemorrhagic and exerted mass effect. One patient showed increasingly nodular and heterogeneous ring-like enhancement progressing from the single-dose to the triple-dose gadolinium contrast images. The CVI of a second patient also showed ring-like enhancement. Biopsy was performed on one of these patients and was strongly considered for the other two patients to exclude neoplastic disease. Careful examination of the MRI appearance of venous structures and the use of specialized MRI techniques improved the recognition of CVI for two patients and prevented biopsy. This represents the first description of abnormal triple-dose MRI contrast enhancement in CVI. Consideration of CVI in the care of patients with enhancing tumor-like masses may lead to earlier diagnosis and treatment, preventing unnecessary invasive diagnostic procedures. CVI should be added to the differential diagnosis of supratentorial ring-enhancing masses.

Adult↗
PubMed1994

MRI volumetry of medial temporal lobe structures in amnesia following herpes simplex encephalitis.

Using a magnetic resonance imaging-based volumetry, we quantified the volumes of the hippocampal formation (HF), parahippocampal gyrus (PHG), amygdaloid body (AMB), and anterior temporal neocortex (ATN) in 5 post-herpes simplex encephalitic (post-HSE) patients with temporal lobe damage and memory impairment at 12-52 months after the onset, and in 10 age-matched control subjects. In the post-HSE patients, the HF (p < 0.001) and PHG (p < 0.005) were significantly atrophic, while the AMB (p = 0.155) and ATN (p = 0.102) were smaller but not significantly. Performances on the verbal learning memory tests correlated highly with the HF volume, and length of dense retrograde amnesia with the PHG atrophy. Two patients with severe lasting amnesia had a marked atrophy of the HF and PHG, while 3 patients with good recovery from initial amnesia had temporal lobe structures larger than 50% of the control mean volumes. These results suggest that anterograde and retrograde memory functions involve different neural structures; the former is related to the HF and the latter to the PHG. For producing lasting amnesia, either severe HF damage or a combined damage of the HF and PHG might be necessary.

Acyclovir↗
PubMed2006

Familial, structural, and environmental correlates of MRI-defined bone marrow lesions: a sibpair study.

The aim of this study was to estimate the heritability and describe the correlates of bone marrow lesions in knee subchondral bone. A sibpair design was used. T2- and T1-weighted MRI scans were performed on the right knee to assess bone marrow lesions at lateral tibia and femora and medial tibia and femora, as well as chondral defects. A radiograph was taken on the same knee and scored for individual features of osteoarthritis (radiographic osteoarthritis; ROA) and alignment. Other variables measured included height, weight, knee pain, and lower-limb muscle strength. Heritability was estimated with the program SOLAR (Sequential Oligogenetic Linkage Analysis Routines). A total of 115 siblings (60 females and 55 males) from 48 families, representing 95 sib pairs, took part. The adjusted heritability estimates were 53 +/- 28% (mean +/- SEM; p = 0.03) and 65 +/- 32% (p = 0.03) for severity of bone marrow lesions at lateral and medial compartments, respectively. The estimates were reduced by 8 to 9% after adjustment for chondral defects and ROA (but not alignment). The adjusted heritability estimate was 99% for prevalent bone marrow lesions at both lateral and medial compartments. Both lateral and medial bone marrow lesions were significantly correlated with age, chondral defects, and ROA of the knee (all p < 0.05). Medial bone marrow lesions were also more common in males and were correlated with body mass index (BMI). Thus, bone marrow lesions have a significant genetic component. They commonly coexist with chondral defects and ROA but only share common genetic mechanisms to a limited degree. They are also more common with increasing age, male sex, and increasing BMI.

Adult↗
PubMed1984

Influence of structure on the reduction of nitroxide MRI contrast-enhancing agents by ascorbate.

With an eye toward the design of new nitroxide-based magnetic resonance imaging (MRI) contrast agents, the effect of ring size and the presence of proximate polar groups on the rate of reduction of cyclic nitroxides by the biologically relevant reducing agent ascorbate ion have been determined. To the extent that reduction by ascorbate ion is indicative of the behavior of nitroxides toward other in vivo reducing agents, our results indicate that saturated five-membered cyclic nitroxides are to be preferred over smaller or larger ring sizes or acyclic nitroxides. Proximate polar groups tend to enhance the susceptibility toward reduction by ascorbate.

Ascorbic Acid↗
PubMed1991

High-resolution magnetic resonance imaging of the interphalangeal joints of the hand.

High-resolution magnetic resonance imaging (MRI) of the interphalangeal joints of the fingers is being employed to study arthritis. To facilitate this research, a clear understanding of the structures visualisable by MRI is necessary. A gradient echo (GE) sequence was developed that produced good contrast between cartilage and other joint structures. These detailed images, with an in-plane resolution of 200 x 100 microns, enable resolution of three cartilage zones which can be interpreted as a superficial layer at the cartilage/cartilage interface, an intermediate layer and calcified cartilage in contact with bone; these correlate well with known anatomy. Further analysis of the images indicates that although a chemical shift artifact causes changes in the images at the field strength used (0.5 T), it does not cause enough distortion to necessitate suppression of the effect. Furthermore, the only detectable susceptibility artifact at these low field strengths was a loss of signal in bone trabeculae at the bone/cartilage interface. There is clearly potential in the study of the articular structures, in particular cartilage, in detail, using high-resolution MRI.

Adult↗
PubMed1995

Caudate, putamen, and globus pallidus volume in schizophrenia: a quantitative MRI study.

Basal ganglia structures have been reported to be abnormal in schizophrenia. However, while component structures of the basal ganglia are functionally differentiated, there have been no evaluations of their separate magnetic resonance imaging (MRI) volumes with small voxel (1.5 mm3) spoiled gradient-recalled acquisition in steady state techniques and multi-plane assessments. We examined MRI scans from 15 male, right-handed, neuroleptic-medicated schizophrenic patients and 15 age-, handedness-, and gender-matched normal volunteers. Compared with normal subjects, schizophrenic patients showed enlarged volumes: 14.2% for total basal ganglia, 27.4% for globus pallidus, 15.9% for putamen, and 9.5% for caudate. Increased volumes, especially of the caudate, were associated with poorer neuropsychological test performance on finger tapping and Hebb's Recurring Digits. These findings indicate abnormalities throughout all basal ganglia structures in at least a subgroup of schizophrenic patients.

Adult↗
PubMed2004

Memory relationships between MRI volumes and resting PET metabolism of medial temporal lobe structures.

Prior studies of temporal lobe epilepsy (TLE) patients showed that MRI volumes and resting PET scan measures of temporal lobe structures were related to memory. Weintrob and colleagues [Ann. Neurol. 2002;51:442-7] reported that PET glucose uptake in the left perirhinal cortex predicted verbal paired associate (PA) learning, whereas MRI volume of the left hippocampus did not. We investigated whether MRI volumes could account for memory functioning if both PET and volumes were from the same region in 18 TLE patients. Volumes and glucose uptake of the hippocampus and parahippocampal gyrus (PHG) were compared with WMS-III performance. Significant correlations were observed between hippocampal volumes and PA and Logical Memory (LM) Percent Retention, but not between memory and PHG volumes or any PET measures. Multiple regression revealed that hippocampal volumes, but not PHG volumes or PET, significantly predicted PA and LM retention scores. These findings suggest that hippocampal volumes provide unique information regarding memory.

Adolescent↗
PubMed2002

[MR imaging of gastric wall layers in vitro: correlation to thehistologic wall structure].

PURPOSE: To correlate gastric wall layers visible of MRI with the anatomical structure of the gastric wall. METHODS: After macroscopic preparation 5 x 5 cm post-mortem tissue sections of the gastric antrum were evaluated using a 2.4 Tesla MR unit (Bruker, Ettlingen, Germany). MR imaging consisted of T2-weighted multi-spinecho sequences in longitudinal and axial directions. The specimens then were stained with hematoxylin-eosin for histological examination. After that histological correlation of the gastric wall layers visible on MRI was performed. RESULTS: In all specimens four gastric wall layers could be clearly identified on MRI. The direct comparison of those layers to the histological findings showed the following correlation: 1) intermediate signal = mucosa, 2) hypointense signal = lamina muscularis mucosae, 3) hyperintense signal = submucosa, 4) intermediate signal = muscularis propria. CONCLUSIONS: Gastric wall layers visible on MRI were successfully correlated to the anatomic layers of the gastric wall. This allows us for the first time to classify invasion of gastric carcinoma using high spatial-resolution MR imaging. However, the subserosa and serosa are excluded from this conclusion, because so far a reliable statement concerning the value of MRI to depict these very variable layers is not possible.

Cadaver↗
PubMed2005

Magnetic resonance imaging of microneurovascular free muscle flaps in facial reanimation.

The purpose of this study was to describe the survival and volume of microneurovascular muscle flaps at different times after two-stage facial reanimation procedure by using magnetic resonance imaging (MRI) and to compare the functional outcome with MRI findings. Fifteen patients with a mean age of 36 years (range 7-63 years) operated on between 1988 and 1999 were available for this study. The muscles used for functional reconstruction were the latissimus dorsi (eight patients), gracilis (six patients) and serratus anterior (one patient). Hospital charts were reviewed and the clinical outcome of facial reanimation was graded on a scale from 1 to 6 according to House. The mean postoperative follow-up time was 7 years (range 3-14 years). Clinical grading and 1.5 T unit MRI of patients were performed concomitantly. The MR images were evaluated semi-quantitatively so that the muscle structure of the free flaps was graded on a scale from 1 to 4. The free flap area of each slice was defined and the volume of the free flap was calculated. Data were analysed statistically. The long-term functional outcome of the facial reanimation was regarded as good in 10 patients, which means they had only mild or moderate dysfunction of facial movements. In MR images, six free flaps displayed normal muscle structure, another six had a fatty appearance and two displayed severe muscle atrophy; in one patient the muscle tissue could not be identified. The volume of the free flap clearly declined in the course of the follow-up. A correlation was found between good functional outcome and normal muscle structure of the free flap in MRI, p = 0.020. The longer the follow-up time after muscle transplantation the poorer the functional result. A similar correlation was found between abnormal muscle structure in MRI and a long follow-up time. Magnetic resonance imaging can be used to assess the muscle structure of free microneurovascular flaps. Normal findings in MRI seem to correlate with a good clinical outcome in facial reanimation. A good functional result correlates with a shorter follow-up time and normal muscle structure in MRI.

Adolescent↗
PubMed2002

Syndromic diagnosis at the epilepsy clinic: role of MRI in lobar epilepsies.

PURPOSE: Magnetic resonance imaging (MRI) is an essential diagnostic tool for the management of epilepsy at modern epilepsy clinics. This study was conducted to incorporate MRI features into the international classification of epilepsies and epilepsy syndromes (ICEES) proposed by the International League Against Epilepsy (ILAE). METHODS: Three hundred consecutive patients newly registered in the Yonsei Epilepsy Clinic underwent stepwise classifications based on clinical features, clinical EEG, and clinical EEG-MRI correlations. The patients were required to have epilepsy and have undergone both EEG and MRI for inclusion in the study. Interictal epileptiform discharges (IEDs) in the EEG were divided into lobar, multilobar, and generalized. MRI lesions were divided into lobar and multilobar lesions. Lobar epilepsies (LEs) were divided into temporal, frontal, parietal, occipital, rolandic, temporoparietooccipital junctional, multilobar, and nonlocalized LEs. RESULTS: Two hundred forty-nine patients satisfied the inclusion criteria. In the first-step diagnosis, 190 patients were classified as having localization-related epilepsy; 24 patients, generalized epilepsy; 34 patients, undetermined epilepsy; and one patient, a special syndrome. EEG revealed IEDs in 124 (50%) patients, and the second-step diagnosis changed the diagnostic categories of 79 (32%) patients. MRI detected lesions in 106 (43%) patients, and the third-step diagnosis changed the diagnostic categories of 30 (12%) patients. The nonspecific diagnostic categories of ICEES decreased from 49% to 37% and then to 29%, as diagnosis progressed from steps one to three. In cases of LE, MRI was superior to EEG in its clinical correlation. Additionally, the diagnostic precision in temporal lobe epilepsy was far better than that for other LEs. CONCLUSIONS: The impact of MRI on ICEES was only modest in terms of changing diagnostic categories, although MRI provided a structural substrate for epilepsy in 38% of patients with negative EEGs. In LE, MRI was as sensitive as EEG, and its clinical correlation was superior to that of EEG, which strongly supports the rationale of incorporating MRI into ICEES.

Adult↗
PubMed2000

MRI measurements of normal extraocular muscles and other orbital structures.

BACKGROUND: Studies of extraocular muscle (EOM) by magnetic resonance imaging (MRI) need to be extended to normal subjects of different ages to obtain data on the muscle thickness, cross-sectional area, and the volume of EOM and other orbital tissues. METHODS: Forty-two orbits of 21 normal subjects in three age groups with an age range of 19-70 years were examined with surface-coil MRI. The transverse and sagittal images were used to measure the thickness of the four rectus muscles during fixation in different gaze positions. The coronal images with eyes in the primary position were used to calculate the cross-sectional areas. The volumes of all six EOM, orbital fatty tissue, the optic nerve and the eyeball were measured in the coronal plane and in either the transverse or the sagittal plane. RESULTS: The horizontal muscles were thinner than vertical muscles. Muscle volume was larger in SR (superior rectus) than in IR (inferior rectus), larger in SO (superior oblique) than in IO (inferior oblique), and the same in LR (lateral rectus) as in MR (medial rectus). No significant differences were found in the values of the cross-sectional area in any image plane between the three age groups. There were no significant differences in muscle thickness and size and fatty tissue volume between age groups. The muscle thickness was linearly correlated to the angle of the eye deviation for all four rectus muscles, both in the "on" and "off" directions of the muscles. CONCLUSIONS: The study provides quantitative data, in normal subjects of different ages, on the thickness and size of EOM and the volume of other orbital tissues by MRI, to serve as a basis for further studies on the morphological changes of EOM in various orbital diseases.

Adult↗
PubMed2006

Do MRI findings correlate with mobility tests? An explorative analysis of the test validity with regard to structure.

To find out whether segmental magnetic resonance imaging (MRI) findings such as intervertebral disc degeneration (DD) and facet joint osteoarthritis (FJO) are associated with motion deficiencies as seen in common mobility tests and observed range of motion (ROM). A total of 112 female subjects, nurses and office workers, with and without low back pain, were examined by clinical experts, and lumbar mobility was measured including modified Schober, fingertip-to-floor distance (FTFD) and ZEBRIS motion analysis. An MRI of the lumbar spine was made. Mobility findings were correlated with segmental morphologic changes as seen on MRI at the levels of L1-2 through L5-S1. Only a few statistically significant correlations between MRI findings and the results of the mobility tests could be found. Lateral bending was weakly and negatively correlated to DD and FJO but only on the level of L5-S1. The FTFD showed a weak positive correlation to endplate changes on the level of L4-5. When ROM is observed by clinical experts, there are several significant relationships between MRI findings and the observed motion. There is a highly significant segmental correlation between DD and disc form alteration as seen on MRI on the level of single motion segments. Pain history and current pain level did not moderate any association between MRI and mobility. There is no clear relationship between the structural changes represented by MRI and the measured mobility tests used in this study. Our findings suggest that close observation of spinal motion may provide at least equal information about the influence of spinal structures on motion than the commonly used measured mobility tests do.

Adult↗
PubMed1986

Ipsilateral blepharospasm and contralateral hemidystonia and parkinsonism in a patient with a unilateral rostral brainstem-thalamic lesion: structural and functional abnormalities studied with CT, MRI, and PET scanning.

A patient developed progressive right hemidystonia in childhood. Subsequently, left-sided blepharospasm, slurred and stuttering speech, and right-sided rigidity and bradykinesia, responsive to dopamine agonists, appeared. Investigation with computed tomography and magnetic resonance imaging (MRI) at age 43 years revealed a left-sided calcified rostral brainstem-thalamic lesion of uncertain aetiology. Although no structural lesion was seen in the striatal regions, L-[18F]-fluorodopa uptake was severely diminished in the left striatum but normal on the right. Dopamine receptor binding identified by [11C]-methylspiperone was in the normal range on both sides.

Adult↗
PubMed1998

Quantitative MRI in patients with idiopathic generalized epilepsy. Evidence of widespread cerebral structural changes.

In patients with idiopathic generalized epilepsy (IGE), visual inspection of routine MRI is normal. However, pathological studies have shown microdysgenesis in grey and white matter in a large percentage of autopsies from cases of IGE. Recently, widespread structural changes not evident on visual inspection of high resolution MRI have been shown using quantitative MRI in patients with apparently focal cerebral dysgenesis. We sought to determine whether similar quantitative changes might be present in patients with IGE, reflecting possible underlying structural abnormalities. Twenty patients with juvenile myoclonic epilepsy, 10 patients each with childhood absence epilepsy and juvenile absence epilepsy, five patients with tonic-clonic seizures on awakening and 30 control subjects had T1-weighted volume acquisition MRI scans on a 1.5T GE scanner. The cerebral hemispheres were segmented semi-automatically, allowing the comparison of normalized cortical and subcortical matter volumes between groups, and investigation of the regional distribution of cortical and subcortical matter in individual subjects. Patients with IGE had significantly larger cortical grey matter volumes than control subjects. Significant abnormalities of the regional distribution of cerebral grey and subcortical matter were found in eight out of 20 patients with juvenile myoclonic epilepsy, one out of 10 patients with childhood absence epilepsy, four out of 10 patients with juvenile absence epilepsy and two out of five patients with tonic-clonic seizures on awakening, but in none of the 30 control subjects. Using MRI-segmentation, we identified widespread cerebral structural changes in patients with various IGE syndromes. Quantitative MRI supports the existence of structural abnormalities in patients with IGE.

Adolescent↗