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PubMed2026

Longitudinal functional network connectivity changes across the clinical stages of C9orf72 hexanucleotide repeat expansion carriers.

INTRODUCTION: Intrinsic functional connectivity network abnormalities in C9orf72 hexanucleotide repeat expansion carriers emerge during the asymptomatic phase, yet longitudinal studies remain limited. We examined cross-sectional abnormalities and longitudinal connectivity changes across clinical stages. METHODS: We analyzed task-free functional magnetic resonance imaging (fMRI) and structural MRI data in 36 asymptomatic (aSxC9), 17 prodromal (proC9), and 29 symptomatic (SxC9) carriers, and 107 healthy controls (HCs). Functional networks previously found altered in C9orf72, including salience, sensorimotor, default mode, and medial pulvinar thalamic networks, were examined. Associations between longitudinal connectivity and gray matter decline with baseline neurofilament light chain (NfL) concentrations and symptom severity were assessed. RESULTS: aSxC9 and SxC9 showed longitudinal connectivity changes within specific networks. In aSxC9, connectivity changes correlated with baseline NfL. In proC9 and SxC9, changes in connectivity and gray matter were associated with baseline NfL and symptom severity. DISCUSSION: C9orf72 expansion carriers demonstrate stage-specific network connectivity changes.

Humans↗
PubMed1994

1H-magnetic resonance spectroscopy of the left temporal and frontal lobes in schizophrenia: clinical, neurodevelopmental, and cognitive correlates.

Twenty eight schizophrenic patients and 20 normal volunteers underwent proton magnetic resonance spectroscopy (MRS) on the left temporal and frontal lobe regions. Male patients showed a significant reduction in frontal but not temporal n-acetylaspartate (an intraneuronally distributed metabolite) in comparison with either male controls or female patients; frontal choline was raised in male patients relative to these groups. Putative neurodevelopmental indices, including obstetric complications, family history of schizophrenia, and minor physical anomalies, proved unrelated to MRS resonances. However, multiple aspects of memory function in patients were related to temporal but not frontal creatine, a pattern that was not apparent among controls. These MRS findings complement some previous structural MRI studies and much clinical and epidemiological evidence of important gender differences in schizophrenia. The findings also suggest that memory dysfunction in patients with schizophrenia may be associated with a particular pattern of temporal lobe metabolism on MRS.

Adult↗
PubMed1989

Very-low-birth-weight, preterm infants with or without intracranial hemorrhage. Neurologic, cognitive and cranial MRI correlations at 4-8-year follow-up.

Fourteen very-low-birth-weight (VLBW) preterm infants with and without intracranial hemorrhage (ICH) were prospectively followed from birth to 4 to 8 years for the purpose of determining neurologic and cognitive sequelae associated with ICH severity and to correlate outcomes with brain morphology as determined by Magnetic Resonance Imaging (MRI). Intracranial hemorrhage was documented by cranial ultrasonography performed in early life. Follow-up assessments included neurologic and psychometric examinations and cranial MRI scans. Of six children with no ICH, five had normal results on all three follow-up measures. Three children with Grade I-II ICH had mild to moderate neurologic and cognitive sequelae with focal white matter MRI abnormalities. Five children with Grade III-IV ICH had severe neurologic, cognitive, and MRI deficits, including MRI regional and diffuse white matter abnormalities and/or cortical atrophy. Focal and diffuse neurologic deficits correlated with the extent of MRI morphologic abnormalities. Results of this study indicate that ICH severity correlated with outcomes in children at follow-up; the more severe the ICH, the more adverse the neurologic, cognitive, and MRI results. MRI white matter abnormalities were present in all children with any degree ICH, while ventriculomegaly was seen only in severe ICH (Grade III-IV ICH). Neurologic deficits correlated with MRI structural abnormalities.

Brain↗
PubMed1988

Neck pain.

Six conditions cause most of the neck pain complaints seen by primary care physicians: cervical muscle strain or sprain, torticollis, acceleration injury, myofascial pain dysfunction syndrome, and cervical osteoarthritis or rheumatoid arthritis. Most of them can be diagnosed and treated by the primary care physician. Of the more unusual causes, one should not miss a clinical fracture; a herniated cervical disc, spinal cord compression from a disc, or epidural tumor; infection of the disc or the vertebral body; subluxation of the vertebral bodies; or pain referred from the chest or mediastinal structures. MRI offers new opportunity for early diagnosis of myelopathy owing to OA or RA, vertebral osteomyelitis, and metastatic involvement of cervical vertebrae.

Humans↗
PubMedDate not supplied

Assessment of posterior fossa structures with midsagittal MRI: the effects of age.

Midsagittal magnetic resonance (MR) images of 36 normal volunteers, ranging in age from 26 to 79 years, were used to evaluate the effects of age on the size of posterior fossa structures (cerebellar vermis, midbrain, pons, medulla and fourth ventricle). Our results demonstrate a highly statistically significant age-related decline in the cross-sectional area of the midbrain (r = -.44, p less than 0.007), a less prominent decline in the area of the anterior cerebellar vermis (r = -.33, p less than 0.05) and striking intercorrelations between the dimensions of the pons, medulla and cerebellar vermis. To the best of our knowledge, this is the first MRI demonstration of midbrain atrophy during aging in normal adults.

Adult↗
PubMed1994

Volumetric MRI assessment of temporal lobe structures in schizophrenia.

This magnetic resonance imaging (MRI) study was designed to investigate whether patients with schizophrenia have focal or lateralized deficits in the volumes of temporal lobe structures. Estimated volumes of the temporal lobes, hippocampi, superior temporal gyri, lateral ventricles, third ventricle, temporal horns of the lateral ventricles, and a frontal-parietal reference area (FPRA) were quantified for each hemisphere. The schizophrenic group had less gray matter (GM) in the temporal lobes and the FPRA relative to controls. Ventricular volumes were significantly larger in the schizophrenic group, as was cerebrospinal fluid (CSF) volume for temporal lobe sulci. No significant differences in hippocampal volumes emerged between groups. The magnitude of GM deficit was not greater in the temporal lobes relative to the FPRA. These results confirm the presence of bilateral GM volume deficits of the temporal lobes in schizophrenia but do not support the hypothesis that structural changes preferentially affect the temporal lobes or the left cerebral hemisphere.

Adult↗
PubMed1990

MRI findings in medial temporal lobe structures in schizophrenia.

In an MRI volumetric study of 10 young male schizophrenics (DSM-III-R 295.9x) a temporal lobe segment, corresponding hippocampal formation and parahippocampal gyrus were found smaller as compared with healthy controls while temporal horn was enlarged. Temporal lobe segment and parahippocampal gyrus were larger on the right in patients and controls, reversed asymmetry was found for the hippocampus.

Adult↗
PubMed1987

Nitroxides as potential contrast enhancing agents for MRI application: influence of structure on the rate of reduction by rat hepatocytes, whole liver homogenate, subcellular fractions, and ascorbate.

With an eye toward the development of nitroxides as potential contrast enhancing agents for MRI applications, we have compared the rates of reduction of 24 nitroxides of diverse structures by rat whole liver homogenate, hepatocytes, subcellular fractions, and ascorbate (10 eq excess). Our results indicate that five-membered ring nitroxides and alpha-carboxy alpha-aryl tert-butyl nitroxides are significantly more resistant toward bioreduction than six-membered ring and heterocyclic-substituted nitroxides in all systems. In the case of six-membered ring nitroxides the presence of either negatively charged or positively charged groups increases the susceptibility toward ascorbate reduction. The presence of carboxylate groups tends to enhance the resistance of all the nitroxides toward reduction by liver homogenate, hepatocytes, and subcellular fractions. trans-Azethoxyl nitroxides exhibited the best overall resistance toward bioreduction. The T1 relaxants of selected nitroxides were measured and found to be similar.

Animals↗
PubMed1988

Comparative chemical structure and pharmacokinetics of MRI contrast agents.

The blood clearance kinetics of five gadolinium complexes, Gd(L), were determined in rats and the results interpreted in terms of an open two-compartment pharmacokinetic model. The complexes were tested in vitro for stability in serum and in aqueous solutions of ions that they might encounter in vivo and that might be expected to react with the Gd(L) complexes to produce uncomplexed gadolinium. Reaction with serum was observed in two instances. Chemical structural differences among the chelating ligands appear to govern the overall reactivity of their Gd(L) complexes. It may be inferred from the results that a preferred structural feature of the ligand is the presence of a 12-membered 1,4,7,10-tetraaza macrocycle.

Animals↗
PubMed1992

The clinical utility of magnetic resonance imaging in 3-dimensional treatment planning of brain neoplasms.

Results of the clinical experience gained since 1986 in the treatment planning of patients with brain neoplasms through integration of magnetic resonance imaging (MRI) into computerized tomography (CT)-based, three-dimensional treatment planning are presented. Data from MRI can now be fully registered with CT data using appropriate three-dimensional coordinate transformations allowing: (a) display of MRI defined structures on CT images; (b) treatment planning of composite CT-MRI volumes; (c) dose display on either CT or MRI images. Treatment planning with non-coplanar beam arrangements is also facilitated by MRI because of direct acquisition of information in multiple, orthogonal planes. The advantages of this integration of information are especially evident in certain situations, for example, low grade astrocytomas with indistinct CT margins, tumors with margins obscured by bone artifact on CT scan. Target definitions have repeatedly been altered based on MRI detected abnormalities not visualized on CT scans. Regions of gadolinium enhancement on MRI T1-weighted scans can be compared to the contrast-enhancing CT tumor volumes, while abnormalities detected on MRI T2-weighted scans are the counterpart of CT-defined edema. Generally, MRI markedly increased the apparent macroscopic tumor volume from that seen on contrast-CT alone. However, CT tumor information was also necessary as it defined abnormalities not always perceptible with MRI (on average, 19% of composite CT-MRI volume seen on CT only). In all, the integration of MRI data with CT information has been found to be practical, and often necessary, for the three-dimensional treatment of brain neoplasms.

Astrocytoma↗
PubMed1989

Marchiafava-Bignami disease with recovery diagnosed by CT and MRI: demyelination affects several CNS structures.

Marchiafava-Bignami disease (MBD) is a rare complication of chronic alcoholism. Most reported cases have been diagnosed at autopsy. With CT and, especially, MRI it is possible to diagnose MBD in its early stages. Lesions of CNS structures other than the typical demyelination of the corpus callosum are described ante mortem in a patient with MBD. The more frequent use of CT and MRI in sudden onset encephalopathies of alcoholics could reveal the real incidence of MBD, and the consequent detection of other involved CNS systems might improve our knowledge about the aetiology, pathogenesis, prognosis and therapy of MBD.

Alcoholism↗
PubMed1985

X-ray and magnetic resonance stereotaxy for functional and nonfunctional neurosurgery.

By means of new plastic stereotactic ring and head fixers, stereotactic procedures can be combined with MRI, with stereotactic coordinates obtained from the MRI images. The method was rechecked against CT stereotaxy and shows a good correspondence of the target coordinates. With MRI stereotaxy, structures near bony regions will be more accessible than with CT stereotaxy. Moreover, the MRI procedure seems to have advantages for functional therapy without the necessity of contrast ventriculography.

Brain Neoplasms↗
PubMed1990

[Results of magnetic resonance and computerized tomography studies of augmentation plastic surgery of the anterior cruciate ligament using carbon fibers. II].

19 patients out of those described in part I were examined by MRI and CT. We quote MRI as an excellent new mean of imaging without exposure to ionising radiation which renders sufficient information about the internal knee-structures without surgical invasion. The signal density for the neoligament as well intraarticular as in the "over the top"-position gives evidence for the ingrowth of mesenchymal structures. The MRI diagnosis was proved by histological examination in 2 cases. Very good correspondence between clinic examination and the CT-images could be found. On top of that the tibial drilling holes could be shown in an excellent way. The CT-scan is a fine instrument to judge the postoperative state of the anterior cruciate ligament. The density measurement inside and outside the bone gives evidence for mesenchymal growth inside the carbon fibre structure and the existence of a new natural ligament.

Anterior Cruciate Ligament↗
PubMed1989

Computed tomographic evaluation of fatty neoplasms of the extremities. A clinical, radiographic, and histologic review of cases.

Eleven lipomatous tumors of the extremities (7 liposarcomas, 4 lipomas) were evaluated radiographically by several modalities, including computed tomography (CT) in all lesions. Lipomas were seen on CT scan as well delineated, homogeneous masses with negative attenuation coefficients ranging from -95 to -160. Liposarcomas were inhomogeneous, multilobulated, poorly delineated lesions located exclusively in the subfascial or intramuscular planes, with an intermediate range of attenuation coefficients between those of fat and those of muscle. In six of seven liposarcomas, definite low density areas were identified by attenuation coefficient as fatty tissue. Magnetic resonance imaging (MRI) was obtained in two patients and was helpful in defining the extent of the tumors and their relationship to vital structures, but MRI could not differentiate benign from malignant tissue. Computed tomography is recommended as the cornerstone in the initial radiographic evaluation of growing or painful lipomatous soft tissue masses of the extremities.

Adult↗
PubMed1991

[Diagnostic yield in rhino-sinusal inflammatory pathology: comparison of projective radiology, CT and MR].

In everyday practice, the radiologist is concerned with the diagnosis of inflammatory conditions of the nose and paranasal sinuses. This paper was aimed at evaluating and comparing the diagnostic efficacy of the main diagnostic imaging procedures currently available. Fifty-six patients were studied: 25 with computed radiography (CR) and CT, 21 with CR and MRI (0.22 T resistive magnet), and 10 with CR, CT, and MRI. From the diagnostic point of view, the conventional-like CR image was assumed as analog to the conventional radiographic (RX) one on the basis of previous personal experience. The following elements were separately considered for RX, CR, CT, and MRI: anatomical structure identificability, spatial resolution, dosimetry, time consumption, diagnostic results, and economics. A global performance index was calculated (RX less than 1; CR = 1; MRI ranging 1.2-2.2; CT = 7.3). CR was superior to RX, from both a diagnostic and a dosimetric point of view, but buying the equipment is nowadays expensive. CT and MRI were superior to both RX and CR in the diagnosis of inflammatory conditions of the nose and paranasal sinuses. When an inflammatory condition is unquestionable, MRI is more accurate than CT, but the latter (thanks to its optimal documentation of both bony walls and soft tissues) is superior to MRI in the differential diagnosis of a generic disease of the nose and paranasal sinuses--that is, when the inflammatory nature is questionable. MRI limitations were poor visualization of bone walls, high cost, and poor access. Thus, CT emerged as the technique of choice, thanks to its diagnostic results, easy access and low cost, with a negligible radiation dose to patients.

Adult↗
PubMed1992

Magnetic resonance imaging of the spine. Normal anatomy.

Standard anatomy of the spine may be found in anatomy and radiology textbooks. However, there are aspects of spinal anatomy that are of particular importance to magnetic resonance imaging (MRI). The structure and orientation of the facet joints and their relationship to the neural foramina receive relatively little attention in standard anatomic works, but they are of great importance in evaluating nerve root compression syndromes. Similarly, the relationships between the cross-sectional diameters of the spinal canal, the subarachnoid space, and the spinal cord assume a great deal of significance when evaluating patients with signs or symptoms of spinal stenosis. Changes in the configurations and composition of the spinal cord will become increasingly important to the radiologists as it becomes possible to identify and distinguish spinal cord grey and white matter. Degenerative syndromes of the spinal cord may be more thoroughly evaluated once MRI permits identification of the specific regions or structures of the cord in which the tissue loss has been most severe.

Humans↗
PubMed1992

[Efficacy of magnetic resonance imaging in treatment of neuroblastoma].

Magnetic resonance imaging (MRI) was performed in 36 children with neuroblastoma at Chiba University from 1984 through 1989, and 29 patients of them were discussed about efficacy of MRI in treatment of neuroblastoma in this paper and the results were as follows. 1) MRI was difficult to differentiate tumor from normal kidney in the image intensity and was more efficient in determining the relationship of tumor to liver and to vascular structures. 2) MRI was better than CT in detecting the size and extent of tumor mass and in identifying lymph node spread using multiple planes. 3) MRI was more efficient than CT in defining displacement and encasement of renal vessels by tumor. It was useful to predict to reserve kidney before surgery. 4) MRI was useful to monitor tumor response to combined modalities of therapy. A favorable response was seen as a change in the image intensity in bone marrow metastases of neuroblastoma.

Adrenal Gland Neoplasms↗