PubMed Health⌕ Search

Biomedical subjects

M H Gado

Publications and source records attributed to M H Gado.

At least 19 recordsLinked to original sources
PubMed1992

Simultaneous MR acquisition of arterial and brain signal-time curves.

Regional cerebral blood flow (rCBF) provides important information about local neuronal functional and cerebrovascular status. Determination of rCBF requires sequential measurements of tracer concentration in arterial blood and brain tissue unless the tracer is trapped in the brain in proportion to rCBF. Since gadopentate dimeglumine is not trapped within brain tissue, we have developed the simultaneous dual FLASH pulse sequence (SDFLASH) which sequentially measures the MR signal change in both the internal carotid artery and brain parenchyma simultaneously during the passage of a bolus of paramagnetic contrast material.

Animals↗
PubMed1991

Senile dementia and healthy aging: a longitudinal CT study.

Volumetric indexes of cerebral atrophy obtained by using computed tomography (CT) were measured longitudinally in patients with senile dementia of the Alzheimer type (SDAT) and in healthy elderly control subjects. Measurements were made three times over a 51-month period. Of the original 44 patients with SDAT, five were available for CT examination at the last time of assessment (51 months); in contrast, 41 of the original 58 control subjects were still available for study at 51 months. As a group, scans of SDAT subjects showed greater atrophy than those of control subjects in all volumetric indexes at each time of testing and demonstrated greater progression of atrophy during the study period. However, the overlap of indexes between the patients with SDAT and the control subjects indicates that CT data cannot be used alone to predict the presence or progression of dementia in individual cases.

Aged↗
PubMed1989

Osmotic demyelination syndrome. Lack of pathologic and radiologic imaging correlation.

An otherwise healthy diabetic woman developed severe hyponatremia, her serum sodium ion levels were rapidly corrected to normal, and she had a course of improvement then neurologic deterioration, with seizures and coma developing in the subsequent two days. Imaging studies, including computed tomography and magnetic resonance images of the brain as late as 19 days after the osmotic insult, failed to show pathologically demonstrated demyelinating lesions. Osmotic brain injury induces demyelination in areas of gray-white apposition and, clinically, results in a delayed neurologic deterioration one to three days following the osmotic challenge. Even with magnetic resonance imaging, review of the literature and this experience suggest that osmotic demyelination cannot reliably be imaged during the first month after the insult.

Brain↗
PubMed1989

Clinical experience with ioversol 320 in cranial computed tomographic scanning.

Sixty patients referred to the Mallinckrodt Institute of Radiology at Washington University School of Medicine, St. Louis, participated in an open-label, noncomparative study of the safety, tolerance, and efficacy of the contrast agent ioversol 320 in cerebral computed tomographic (CCT) scanning. None of the patients experienced any drug-related, clinically significant changes in vital signs or any serious adverse reactions; nor did they report experiencing pain when the agent was injected intravenously. In addition, the radiographic quality of the scans was rated as excellent or good for patients who had enhanceable brain lesions. All CCT scans were considered diagnostic. In this series, ioversol 320 proved to be safe, well tolerated, and effective for use in CCT scanning.

Adolescent↗
PubMed1989

Preoperative assessment of parotid masses: a comparative evaluation of radiologic techniques to histopathologic diagnosis.

A double-blind, retrospective analysis of 110 sequentially operated parotid masses compared the usefulness of preoperative radiologic evaluation to histopathologic diagnosis. The radiologic assessment included 25 sialograms, 162 computed tomography scans, and 10 nuclear magnetic resonance images. The diagnosis is influenced by the following four parameters of computed tomography: tumor borders, density, homogeneity, and enhancement. Well-defined borders, a homogeneous appearance, and high density strongly favor the diagnosis of a benign tumor or a low-grade malignancy (96.7%). Ill-defined tumor borders, heterogeneity, and high density indicate mainly a high-grade or recurrent malignancy (68.8%). Ill-defined borders, a heterogeneous appearance, and mixed density identify a lymphoepithelial lesion, lymphangioma, or sialoadenitis (100%). Sialography is cost effective in the evaluation of lymphoepithelial lesions. Computed tomography sialography offers no advantages over computed tomography with intravenous contrast. High-resolution computed tomography with intravenous contrast is highly sensitive for tumor detection (97%). Magnetic resonance imaging is complementary or superior to computed tomography (100%).

Clinical Trials as Topic↗
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↗
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↗
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↗
PubMed1979

Central nervous system lesions biopsied or treated by CT-guided needle placement.

Computed tomography has been utilized to guide a needle into central nervous system lesions as small as one centimeter in diameter. Direct puncture has drained many abscesses effectively, provided material for immediate Gram stain and subsequent culture, and permitted irrigation with appropriate antibioties, Multilocular cerebral lesions and loculated extracerebral fluid collections have been aspirated and treated with this technique. Aspiration of known cystic tumors has reduced their mass and obviated some palliative decompressions. Unresectable gliomas and metastases have been biopsied prior to chemotherapy or radiotherapy. Hemorrhage and other rare complications of biopsy may be detected and immediately treated.

Adolescent↗
PubMed1979

Regional cerebral blood flow and oxygen utilization in superficial temporal-middle cerebral artery anastomosis patients: an exploratory definition of clinical problems.

Regional cerebral blood flow (rCBF) and regional cerebral oxygen utilization (rCMRO2) were measured before and after surgery in nine patients undergoing a superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis to bypass cerebrovascular lesions not amenable to extracranial operative procedures. The objective of these studies was to determine whether measurements of this type could provide objective criteria for surgery as well as assess the effect of surgery. The preliminary data, although limited, suggest that measurements of regional cerebral hemodynamics and metabolism in these patients before and after surgery provide valuable data upon which to develop criteria and assess results. For example, 1) a significant depression of rCBF and rCMRO2 in patients in whom a major cerebral infarction has not occurred, or 2) relative preservation of rCMRO2 despite depressed rCBF seem to be favorable indications for establishing a functioning STA-MCA anastomosis. In such patients, STA-MCA anastomosis can be followed by a return of rCBJ and rCMRO2 to virtually normal levels. Relatively normal rCBF and rCMRO2 in the presence of an occluded internal carotid artery in asymptomatic patients indicates satisfactory collateral circulation and is probably a contraindication to surgery.

Adult↗
PubMed1978

Cerebral hemodynamics and metabolism in pseudotumor cerebri.

A comprehensive analysis of cerebral hemodynamics and metabolism was carried out in 14 patients with pseudotumor cerebri. Tracer techniques were employed to measure cerebral blood flow (CBF) and vascular reactivity to acute changes in arterial carbon dioxide tension and blood pressure, cerebral blood volume (CBV), and the cerebral metabolic rate for oxygen and glucose. There was a small reduction (p less than 0.01) in CBF (44 +/- 7 ml/100 gm/min; normal, 54 +/- 9) with normal vascular reactivity; an increase (p less than 0.005) in CBV (4.8 +/- 0.8 ml/100 gm; normal, 3.6 +/- 0.5), and normal cerebral metabolism. We conclude that an abnormality of the cerebral microvasculature is responsible for an elevation in CBV, but the intracranial hypertension can be explained only by tissue swelling due to an increase in water content. The relationship between the vascular abnormality and the tissue swelling remains to be defined.

Adolescent↗
PubMed1978

Adult idiopathic communicating hydrocephalus with and without shunting.

The outcome in 37 adult patients with idiopathic communicating hydrocephalus treated by ventriculoatrial shunting is presented. Only 33% showed definite improvement, and no diagnostic procedures accurately predicted the outcome of surgery. These were compared with a "control" group of 12 patients who were not shunted; 50% of these were stable for up to 36 months. These findings, and the high frequency of serious complications (35%), suggest caution in recommending a shunt procedure.

Aged↗
PubMed1978

Computerized tomography of the orbit.

The potential for using CT to diagnose orbital lesions is clearly demonstrated in this chapter. The patients discussed were all suffering from proptosis and had other complaints such as visual disturbances, pain, or ophthalmoplegia. CT is superior to ultrasonography in its ability to reproduce anatomical structures, including the retroocular space, bony walls of the orbit, and extraorbital regions, such as ethmoid sinuses and the cranial cavity. Such reproduction helps distinguish lesions arising within the orbit from those invading the orbit from outside. CT not only defines the extent of a lesion but also provides information about the physical properties of the tissue. The remarkable difference on CT between proptosis caused by thyrotoxic disease and that caused by intraorbital tumor or pseudotumor is a striking example of the way in which CT may contribute to more accurate diagnosis.

Adolescent↗
PubMed1977

Computerized cranial tomography and radionuclide imaging in the detection of intracranial mass lesions.

Computerized cranial tomography (CCT) and radionuclide imaging (RI) of the brain are both accurate techniques for detecting intracranial mass lesions. CCT is superior in detecting low-grade gliomas, cystic lesions, parasellar tumors, and brain stem lesions. Overall, CCT detection rates are slightly higher than those with RI, but the use of iodinated contrast media with CCT increases the risk of this examination. There is a significant difference in the generally binary (positive/negative) type of information offered by RI and the more specific information offered by CCT about the pathologic nature of a lesion and its precise location. In the evaluation of patients with suspected intracranial mass lesions, CCT is generally the preferable initial diagnostic test. However, RI may still serve as a satisfactory screening examination in certain well-defined clinical situations.

Brain Abscess↗
PubMed1977

Cerebral blood flow, oxygen utilization, and blood volume in dementia.

Patients with dementia had significant decreases in cerebral blood flow and cerebral oxygen utilization and a mild, but not significant, increase in cerebral blood volume. These studies were not useful in distinguishing patients with cerebral atrophy from patients with normal pressure hydrocephalus, as similar changes in cerebral circulation and metabolism were seen in both groups. Changes in cerebral blood flow after acute decrease in the intracranial pressure also were not helpful differentiating patients with normal pressure hydrocephalus from patients with cerebral atrophy.

Blood Volume↗
PubMed1977

Coxsackie A9 focal encephalitis associated with acute infantile hemiplegia and porencephaly.

The factors underlying acute infantile hemiplegia are seldom identified. Coxsackie A9 focal encephalitis was documented for the first time in a 3-month-old infant with fever, hemiconvulsions, and hemiplegia followed by a static motor deficit and epilepsy. It has been suggested that the acute infantile hemiplegia associated with encephalitis results from an arteritis or venous sinus thrombosis with subsequent cerebral infarction. However, this was not observed in our patient. Rather, a series of brain scans, computerized tomograms, and a cerebral angiogram clearly documented the evolution of a focal necrotizing encephaloclastic process resulting in a porencephalic cyst. Serial cerebrospinal fluid viral cultures were necessary to isolate the etiologic agent (tcoxsackie A9). The infant did not have a neutralizing antibody response to the infecting viral agent despite an apparently intact immune system, which possibly may be explained by the developed of immune tolerance or an insufficient amount of infecting viral antigen. This emphasizes that serologic studies alone may not be adequate to document an acute central nervous system viral infection. This patient also typifies the poor prognosis in infants presenting with acute hemiplegia, fever, and convulsions in the absence of cerebrovascular occlusion.

Acute Disease↗