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Biomedical subjects

M Gado

Publications and source records attributed to M Gado.

At least 37 records · Page 2Linked to original sources
PubMed1986

Correction of positron emission tomography data for cerebral atrophy.

Because positron emission tomography (PET) provides measurements per unit volume of intracranial contents, these measurements may be affected by the inclusion of metabolically inactive CSF spaces in the volume in which they are made. Thus, PET measurements of CBF and metabolism may be artifactually lowered in normal aging and dementia, which are both associated with significant brain atrophy. We describe a method to correct global PET data, averaged over several tomographic slices, for cerebral atrophy by using measurements of CSF space volume obtained with quantitative x-ray computed tomography. The importance of making such a correction is demonstrated using PET measurements of CBF and oxygen metabolism obtained in normal young, normal elderly, and demented subjects.

Adult↗
PubMed1986

In vivo delineation of facial fractures: the application of advanced medical imaging technology.

Advanced medical imaging technology has important advantages over ordinary skull radiography and conventional tomography in the study of facial fractures. Computer-based imaging methods, including computed tomography and magnetic resonance imaging, provide exquisite soft tissue contrast, superior geometrical accuracy, and freedom from overlapping shadows, and permit computer reformating of images. The advantages of computer-based medical imaging for study of facial fractures are identified and illustrated with computed tomographs. Three-dimensional surface reconstruction methods applied to serial high-resolution computed tomography scans of facial fractures are described and evaluated.

Facial Bones↗
PubMed1986

The skeletal anatomy of mandibulofacial dysostosis (Treacher Collins syndrome).

Three-dimensional osseous surface re-formation imaging from CT scans was used to examine the facial skeletons of 14 living patients with mandibulofacial dysostosis. Partial to complete aplasia of the zygomatic process of the temporal bone, mild hypoplasia to aplasia of the frontal process of the zygoma, antimongoloid slant of the transverse orbital axis, and hypoplasia of the medial pterygoid plates and muscles are common to all patients examined. Deformities of the zygoma, zygomatic process of the frontal bone, mandible, and lateral pterygoid plates and muscles vary from minimal to severe, including aplasia. The body of the zygoma is the least affected part of the bone. Right-left asymmetry characterizes these deformities in all patients. The most consistent skeletal aplasia (cleft) in mandibulofacial dysostosis involves the zygomatic process of the temporal bone rather than the zygoma itself.

Adolescent↗
PubMed1985

Computed tomography in chronic seizure disorder caused by glioma.

Since the introduction of computed tomography (CT) in 1974, 137 patients underwent cortical resection for intractable epilepsy. The CT scans of 32 of these patients demonstrated an isolated calcified or hypodense lesion of unknown origin. The mean interval from onset of the seizure disorder to surgery was 11 years. The referring physicians frequently considered these lesions to be of nonneoplastic origin, which usually delayed surgical management. Twenty-six of the 32 patients, however, proved to have a cerebral glioma, seven showing anaplastic changes. Because the majority of these patients were found to have a neoplasm and especially because the CT scan could not distinguish between a well-differentiated glioma and those with anaplastic changes, we recommend early surgical treatment in patients with chronic seizure disorders who are found to have an isolated lesion of unknown origin on CT scan.

Adolescent↗
PubMed1985

Hydrocephalus and mental retardation in craniosynostosis.

We prospectively studied craniosynostosis, regardless of neurologic status, by cranial computed tomography or psychometric testing in 56 children. None of the 27 children with simple craniosynostosis (single or multiple suture involvement) had evidence of hydrocephalus on CT scan. Of the 24 patients with simple craniosynostosis who underwent psychometric testing, 17 were of average intelligence; six were in the low average range. The single mentally retarded child had a history of severe perinatal asphyxia. Hydrocephalus occurred more frequently (five of 23 cases) in children with complex craniosynostosis syndromes, including Pfeiffer syndrome, Crouzon syndrome, and kleeblattschädel deformity. More striking than hydrocephalus, however, was the finding of dysmorphic ventricular dilation in eight patients, including the three children with Apert syndrome and four with Crouzon syndrome. Nineteen of the 25 children with complex craniosynostosis syndromes receiving psychometric testing were of normal intelligence. Four children with borderline normal intelligence had either hydrocephalus or ventricular dilation. The two children with mental retardation were sisters with Crouzon syndrome whose family included other retarded individuals. This study indicates that the incidence of hydrocephalus and mental retardation in craniosynostosis is lower than reported previously.

Acrocephalosyndactylia↗
PubMed1985

Multispectral analysis of magnetic resonance images.

Magnetic resonance (MR) imaging systems produce spatial distribution estimates of proton density, relaxation time, and flow, in a two dimensional matrix form that is analogous to that of the image data obtained from multispectral imaging satellites. Advanced NASA satellite image processing offers sophisticated multispectral analysis of MR images. Spin echo and inversion recovery pulse sequence images were entered in a digital format compatible with satellite images and accurately registered pixel by pixel. Signatures of each tissue class were automatically determined using both supervised and unsupervised classification. Overall tissue classification was obtained in the form of a theme map. In MR images of the brain, for example, the classes included CSF, gray matter, white matter, subcutaneous fat, muscle, and bone. These methods provide an efficient means of identifying subtle relationships in a multi-image MR study.

Basal Ganglia Diseases↗
PubMed1984

Predictive features in mild senile dementia of the Alzheimer type.

Forty-three subjects with mild senile dementia of the Alzheimer type, diagnosed and staged by clinical research criteria, were studied with clinical, psychometric, EEG, visual evoked potential, and CT measures. During the 12 months following entry into the study, 21 subjects progressed to moderate or severe dementia, 21 remained mild, and one was lost to follow-up. Many of the clinical and psychometric measures of impairment were predictive of the progression to moderate or severe dementia. Electrophysiologic and CT measures were not. In a discriminant function analysis, the scores on two measures (the digit symbol subtest of the Wechsler Adult Intelligence Scale and an Aphasia Battery) correctly predicted the stage of dementia 1 year later in 95% of the subjects.

Activities of Daily Living↗
PubMed1983

The longitudinal orbital CT projection: a versatile image for orbital assessment.

The newer generation of CT scanners allows reconstruction of images in coronal, sagittal, and oblique planes from a single set of axial scans. These computer-generated images are described as reformatted. We have found an oblique image reformatted along the plane connecting the apex of the orbit and the center of the globe to be especially useful in assessing orbital disorders. We have named this image the longitudinal orbital projection. This projection allows direct visualization of the inferior rectus muscle and orbital floor in acute and old orbital trauma. With the image produced life size, direct measurements of enophthalmos and proptosis can be made preoperatively and postoperatively, thereby facilitating planning and follow-up. The projection is also useful in combination with other planes of reformation for the localization of tumors. The longitudinal orbital projection is now a routine part of the CT examination of the orbit in our institution. Whereas it already has become an invaluable aid in the diagnosis and follow-up of congenital and acquired orbital lesions, the longitudinal orbital projection promises to clarify the effects of trauma on the inferior rectus muscle and globe position.

Accidents, Traffic↗
PubMed1983

Brain parenchymal density measurements by CT in demented subjects and normal controls.

Parenchymal density measurements of 14 regions of gray and white matter from each cerebral hemisphere were made from CT scans of 25 subjects who had varying degrees of dementia as measured by a global Clinical Dementia Rating, and also from CT scans of 33 normal control subjects. There were few significant differences between the two groups in the mean density value for each of the regions examined, although several individual psychometric tests did correlate with density changes. Moreover, for six regions in the cerebral cortex, and for one region in the thalamus of each hemisphere, we found no significant correlation between the gray-white matter density difference and dementia. There was, however, a loss of the discriminability between the gray and white matter with an increase in the size of the ventricles. These findings may be attributed to the loss of white matter volume.

Aged↗
PubMed1982

Evaluation of the suprasellar cistern by computed tomography.

The normal suprasellar cistern is a five- or six-pointed, starshaped, fluid-filled structure as demonstrated by computerized axial tomography (CAT). At various levels the normal suprasellar cistern contains the major intracranial vessels and their anastomotic channels, the optic nerves, chiasm, and infundibular stalk. The existence of lesions, either intrinsic structures of or extrinsic structures contiguous to the suprasellar cistern can be detected by their effect on the normal anatomy of the suprasellar cistern or by filling defects produced when studied with metrizamide cisternography.

Brain↗
PubMed1982

Volumetric measurements of the cerebrospinal fluid spaces in demented subjects and controls.

Forty-seven subjects 65 to 80 years of age, of whom 20 were demented and 27 were normal, were studied by computed tomography. Volumetric indices of ventricular (V%) and sulcal size (S%) were determined by pixel counts without knowledge of clinical status. V% was 5.30 (+/- 1.92) for the controls and 10.46 (+/- 4.78) for the demented subjects. S% was 6.14 (+/- 2.51) for the controls and 10.61 (+/- 3.32) for the demented subjects. In each case, differences between the two groups were significant (P less than 0.0001). When a subsample of 29 scans were analyzed using linear and volumetric measurements, the linear measurements showed less pronounced differences between the demented subjects and the controls. These findings explain the conflicting results of different investigators concerning variations in ventricular and sulcal size in dementia and normal aging.

Aged↗
PubMed1982

Surgical anatomy of the craniofacial dysostoses: insights from CT scans.

Six patients with midface retrusion secondary to craniofacial dysostoses were evaluated by computer assisted tomography (CT) before and after surgery. Computer reformated life-size images were generated for linear measurements and for assessing the encroachment upon the orbit of the anterior and middle cranial fossae, the lateral displacement of the ethmoids, and the retrusion of the maxilla. Dynamic ocular CT demonstrated alterations in the angle of divergence of the optic nerve with globe movement which made measurements of that angle an unreliable assessment of hypertelorism. Surgical separation of the midface from the base of the skull was shown to be a fracture within the palatine bones between its horizontal and pyramidal processes. The integrity of the antral walls was preserved in all patients, in contrast to the comminution seen with traumatic LeFort III fractures. CT evaluation of patients with midface retrusion has further defined the nature of their anomalies, facilitated operative planning, demonstrated the osteotomies in vivo and reduced radiation exposure.

Adolescent↗
PubMed1979

Functional anatomy of the cerebral cortex by computed tomography.

The authors describe the morphological characteristics that allow recognition of the individual computed tomography slice and determine its sequence in the series. In addition, each slices is "assembled" by defining the different cortical gyri, sulci, and cortical functional areas (based on Brodmann's maps). This work lays the foundation for correlative studies of location of lesions and the clinical picture.

Brain↗
PubMed1978

The effect of size, histologic elements, and water content on the visualization of cerebral infarcts.

We correlated the radiologic and pathologic examination of 13 human brains, analyzing the size, different histologic elements, and water content in 40 ischemic and hemorrhagic infarcts. Acute infarcts appear in the computerized cranial tomographic (CT) image as low density areas due to high content of fluid, however, a histological-chemical correlation is not concomitant. The addition of blood in hemorrhagic infarcts may result in a normal CT image. Subacute infarcts appear as low density areas, with lower attenuation values due to the presence of large amounts of lipids. Subacute lesions with prominent mineral deposits may be negative on CT scan. Chronic infarcts also appear as low density areas due to cavitation and residual fats. Attenuation values are slightly higher than those of subacute infarcts, possibly due to gliosis. Infarcts smaller than 2 cm in diameter are usually not visualized.

Brain↗