Search PubMed⌕ Search

Biomedical subjects

M H Gado

Publications and source records attributed to M H Gado.

At least 37 records · Page 2Linked to original sources
PubMed1988

Optic nerve dysfunction in thyroid eye disease: CT.

Optic nerve dysfunction in thyroid eye disease is thought to be due to compression of the optic nerve by enlarged extraocular muscles near the orbital apex. High-resolution computed tomography (CT) scans of 78 orbits of 31 patients with thyroid eye disease were reviewed. Axial scans alone were inadequate for demonstrating compression of the optic nerve. With a coronal reformatted scan from the axial scans, a muscular index was devised and measured to reflect extraocular muscle impingement on the optic nerve. Orbits with optic nerve dysfunction had significantly higher muscular indices than those without optic nerve dysfunction, supporting the hypothesis that optic nerve dysfunction is usually secondary to compression by enlarged extraocular muscles. Muscular indices of 67% or greater in patients with optic nerve dysfunction were diagnostic of compressive optic neuropathy, while muscular indices of less than 50% appeared to exclude optic nerve compression. A single case of optic nerve dysfunction without muscular compression is also discussed.

Exophthalmos↗
PubMed1988

Comparison of MR and CT myelography in imaging the cervical and thoracic spine.

MR imaging and CT myelography were compared in a retrospective study of 38 patients with suspected lesions of the cervical and thoracic spinal canal and cord. Twenty-eight abnormal cases were found, including spondylosis (9), tumors (8), intramedullary cavities (3), arachnoiditis (3), disk-space-centered infection or osteomyelitis (2), nonneoplastic cord swelling (2), and CSF-borne metastasis (1). MR was equal or superior to CT myelography in depicting cases of cord enlargement, cord compression, and cord atrophy, providing better tissue characterization, no shoulder artifact, and no limitation caused by CSF block. CT myelography was superior to MR in depicting cases of spondylosis and arachnoiditis. It showed superior spatial resolution, which was most pronounced when comparing axial images and hence particularly superior in detecting the lateral extent of disk herniation. Use of surface coils and thin imaging sections is essential for accurate and complete MR evaluation of the cervical and thoracic spine.

Arachnoiditis↗
PubMed1987

Acute cerebral infarction in monkeys: an experimental study using MR imaging.

Magnetic resonance (MR) imaging was performed in five monkeys with experimentally induced acute cerebral infarction to define the MR imaging features and correlate these with computed tomographic (CT) findings, laboratory analysis, and histopathologic studies. Acute infarct (2-4 hours after embolization) was generally visible on MR images but not on CT scans. CT at 24 and 48 hours did show the infarcts. In all cases the infarct was more clearly depicted with MR imaging and was visualized as an area of high signal intensity on T2-weighted images. Spectrometric nuclear MR measurements of the postmortem cerebral tissue confirmed prolongation of both T1 and T2 values similar to that calculated from MR images. At postmortem laboratory testing, the area of infarction detected with MR imaging had decreased specific gravity and increased water content, reflecting edema.

Animals↗
PubMed1987

Periventricular white matter lucencies in senile dementia of the Alzheimer type and in normal aging.

The significance of periventricular lucencies in the white matter on CT in demented patients is not understood. We studied the relationship of these changes to mental status of subjects with senile dementia of the Alzheimer type. A semiquantitative method showed more numerous and extensive lucencies in demented than in healthy elderly. Neuropathologic examination of five subjects with these changes and confirmed Alzheimer's disease revealed diffuse white matter pallor without infarction. There were no hypertensive vascular changes, although limited hyaline thickening was present.

Aged↗
PubMed1986

Suprasellar lesions: evaluation with MR imaging.

The authors retrospectively evaluated the characteristics on magnetic resonance (MR) images of 59 suprasellar lesions and compared them with computed tomography (CT) scans in 55 of the cases in which CT was performed. A diverse number of lesions were included: 17 pituitary adenomas; eight optic or hypothalamic gliomas; six craniopharyngiomas; six vascular anomalies; four lesions with extension into the suprasellar space; three metastases; two each of meningioma, hamartoma, germinoma, sarcoid granuloma, and teratoma; and one each of lymphoma, optic tract hematoma, cerebrospinal fluid-borne metastasis, pituitary hyperplasia, and sphenoid sinus mucocele. MR enabled characterization of lesions containing hemorrhage, fat, flowing blood, mucus, and cyst and allowed more specific diagnoses than CT in 6% of cases. MR was equivalent to CT in allowing lesions to be detected and in 20% of cases more accurately defined altered perisellar anatomy. Vascular abnormalities can be better evaluated with MR, and use of angiography can be avoided in some cases.

Adenoma↗
PubMed1986

Aneurysmal bone cyst of the cervicothoracic spine: computed tomographic evaluation of the value of preoperative embolization. Case report.

In this report, the management of an aneurysmal bone cyst in the cervicothoracic region of an 8-year-old girl is described. Aneurysmal bone cyst is a histologically benign lesion that is often extremely vascular. In the spine, it can cause extensive bone destruction and compress neural structures. Because this lesion may involve all parts of a vertebra, full delineation of the lesion before its excision is important in planning the surgical approach. The value of preoperative embolization to reduce tumor vascularity, allowing total excision, and the improved radiological evaluation of this lesion with computed tomographic scanning are demonstrated.

Angiography↗
PubMed1986

Computed tomography and magnetic resonance imaging in children with rare movement disorders.

Both CT and MR can aid in the differentiation between benign and less favorable pediatric movement disorders. However, MR is the more sensitive imaging modality and thus preferable. This was demonstrated in 18 patients with conditions ranging from idiopathic dystonias to aminoacidopathies, Leigh's disease, and Hallervorden-Spatz disease. In the latter three entities characteristic lesions were shown in the basal ganglia, although not consistently. A specific diagnosis seems possible in Leigh's disease, provided the clinical setting is appropriate.

Adult↗
PubMed1986

Magnetic resonance imaging of spinal cord hemangioblastomas and arteriovenous malformations.

Eight patients with either spinal cord hemangioblastomas (n = 5), spinal arteriovenous malformations (AVM) (n = 2) and intramedullary hematoma (n = 1) were studied by magnetic responance (MR) imaging. All hemangioblastomas, one AVM and the intramedullary hematoma were identified by MR. Compared with other neuroradiologic procedures, MR provided important complementary information in the diagnostic management of spinal hemangioblastomas and proved to be a useful method for noninvasive follow-up in these lesions. MR is an excellent method in the evaluation of intramedullary hematomas. It may also be useful for demonstration of larger intradural AVM and of thrombus formation in AVM after surgery or embolization procedures.

Adult↗
PubMed1986

Osseous anatomy of unilateral coronal synostosis.

High resolution, thin slice computerized tomography (CT) scans with paraxial and three-dimensional surface reconstructions were utilized to document the endocranial, exocranial, and orbital anatomy of non-syndromal unicoronal synostosis (UCS). Eighteen patients with UCS were evaluated qualitatively and quantitatively. Of these, 10 were studied both preoperatively and 1 year postoperatively. The endocranial base in UCS is characterized by a 9 degree angulation toward the synostosis of the anterior cranial base with respect to the posterior cranial base. The exocranial base has a 7 degree angulation toward the synostosis between the midpalatal suture and the posterior cranial base. The locus of angulation appears to be posterior to the anterior clinoids endocranially, and between the maxillopalatopterygoid articulations and the mandibular condyle exocranially. The orbital rim height is greater ipsilateral to the synostosis than contralaterally. The analysis documents the normalizing effect of one of two different surgical procedures upon orbital height. Application of computer assisted medical imaging to the study of UCS has allowed in vivo quantitation of cranial base and orbital dysmorphology for both preoperative assessment and postoperative evaluation.

Adult↗
PubMed1983

Cranial computed tomography and real-time sonography in full-term neonates and infants.

The results of cranial ultrasonography (US) and computed tomography (CT) were compared in 52 full-term neonates and young infants. The chief indications for examination included: increasing head size, dysmorphic features, myelomeningocele, inflammatory disease, and asphyxia. Disorders detected included hydrocephalus, parenchymal abnormalities, intracranial hemorrhage, extraparenchymal fluid collections, and vascular and other developmental malformations. Hydrocephalus and subdural collections were seen in patients referred for all clinical indications, whereas diffuse parenchymal abnormalities, subarachnoid hemorrhage, and intraventricular hemorrhage occurred primarily in patients with hypoxia. CT and US essentially were equivalent in detecting hydrocephalus, moderate to large intraventricular hemorrhages or subdural collections, and large focal parenchymal lesions, although CT was somewhat better in determining the level and cause of obstruction in patients with hydrocephalus and characterizing parenchymal abnormalities. CT was more sensitive than ultrasound in detecting subarachnoid hemorrhage (100% vs. 0%), diffuse parenchymal abnormality (100% vs. 33%), and small intraventricular hemorrhages (100% vs. 0%) but these lesions often were not clinically significant. The results suggest that US should be used as the primary neuroradiological examination in term infants; CT probably should be reserved for further investigation after US in those patients with a history of hypoxia and progressive clinical deterioration.

Brain↗
PubMed1982

Enlarged cerebrospinal fluid spaces in infants with subdural hematomas.

Computed tomography in 16 infants with subdural hematomas showed enlarged basal cisterns, a wide interhemispheric fissure, prominent cortical sulci, and varying degrees of ventricular enlargement. Radionuclide cisternography in eight of the 16 patients showed findings consistent with enlargement of the subarachnoid space rather than those of communicating hydrocephalus. Clinical findings and brief follow-up showed no convincing evidence for cerebral atrophy in 13 patients. These findings suggest that the enlarged subarachnoid space, which is encountered in some infants and may be a developmental variant, predisposes such infants to subdural hematomas.

Brain↗
PubMed1982

Radiologic demonstration of the dorsal medullocervical spur in adult Chiari malformation.

An adolescent female with downbeat nystagmus and long tract signs was evaluated by a number of diagnostic radiologic procedures. Metrizamide CT cisternography was the procedure that established the diagnosis by showing not only the tonsillar herniation, but also the medullocervical deformity characteristic of the Chiari type II malformation. This case report emphasizes the superior diagnostic capability of this technique with respect to conventional radiography in the diagnosis of Arnold-Chiari malformation.

Adolescent↗
PubMed1979

Computerized tomography in the diagnostic evaluation of multiple sclerosis.

Sixty-six patients with a tentative or certain diagnosis of multiple sclerosis (MS) were examined with cranial computerized tomography (CT). Abnormalities found in 19 (29%) included discrete areas of decreased white matter density, enlarged ventricles, cortical atrophy, and focal areas of contrast enhancement. The presence of white matter lucencies and ventricular dilatation correlated with an increased incidence of diffuse hyperreflexia and mental impairment. Since half the patients with contrast-enhancing lesions were clinically stable, their lesions may represent acute asymptomatic plaques. Abnormalities on CT scan were observed more often in older patients whose disease had lasted longer and was clinically more definite. Since findings were sparse in early, less definite disease, the use of CT as a purely diagnostic tool is limited.

Adult↗