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Biomedical subjects

O W Houser

Publications and source records attributed to O W Houser.

At least 19 recordsLinked to original sources
PubMed1992

CT and MR imaging of intracranial tuberous sclerosis.

CT and MR have permitted radiology to play a greater, but not definitive, role in detecting the pathologic components of tuberous sclerosis. SEN may be identified in only 80% of patients. Tubers are more ubiquitous and readily identified by MR in children and adults when the brain is myelinated. Since tubers are predominantly peripheral hypomyelinated lesions, the detection of small lesions may be delayed until an infant is over 16-18 months of age when the myelin will have extended to the junction between the cortical white and gray matter. SEGA typically evolve later during the first and second decades of life. Successful genetic counseling implies a need to detect tuberous sclerosis at a stage during infancy when imaging may fail to confirm the diagnosis, so tuberous sclerosis remains a clinical diagnosis.

Adolescent↗
PubMed1979

Spontaneous internal carotid dissection, hemicrania, and Horner's syndrome.

We describe five patients with angiographic features of dissecting aneurysm of the cervical portion of the internal carotid artery who were seen initially with unilateral headaches and ipsilateral oculosympathetic paresis. This combination of symptoms is a rather common mode of manifestation of this entity.

Adult↗
PubMed1979

Neurologic computed tomography in a defined population group.

A total of 766 residents of Olmsted County, Minnesota, underwent neurologic computed tomography (CT) from June 1973 through 1976; 981 scans were performed. The number of CT scans per 1,000 population increased each year and, during the period studied, the average rate based on the initial scan in each case was 2.4 and the rate based on all scans was 3.1. The age-specific rates were greatest among patients 65 years old or older. If CT use plateaus at about 6 scans per 1,000 population, then under conditions similar to those in this community, a population of approximately 400,000 would be required to assure adequate use of a CT scanner for investigating neurologic disease.

Adolescent↗
PubMed1979

Arteriovenous malformation affecting the transverse dural venous sinus--an acquired lesion.

Dural arteriovenous malformations of the transverse sinus are relatively well localized to the occipitomastoid regions and occur predominantly in women who are more than 40 years of age. The signs and symptoms, except for pulsatile tinnitus, vary and apparently depend on the presence of impaired venous drainage, which may produce increased intracranial pressure, papilledema, and transient or persistent neurologic deficits. Eight of the 14 patients described had occlusion of one or both transverse or sigmoid sinuses. Two patients had angiographic demonstration of sigmoid or transverse sinus occlusion (one 1 year and the other 4 years) before the development of an arteriovenous malformation in the appropriate sinus. Dural sinus occlusion may precede the development of a dural arteriovenous malformation, and the pathogenesis may be partial recanalization of a thrombus.

Adult↗
PubMed1979

Demyelination of the brain in tuberous sclerosis: computed tomography evidence.

Two patients with tuberous sclerosis are described in whom computed tomography of the head revealed areas of diffuse diminution of density suggestive of demyelination. Computed tomography is a sensitive test for the detection of intracerebral lesions in tuberous sclerosis, and the finding of areas of diminished density in the absence of evidence for tumor or ventricular obstruction correlates with the common histologic finding of diffuse demyelination. Serial studies with computed tomography are likely to determine whether such demyelination precedes the growth of hamartomas and calcification that characterize tuberous sclerosis.

Brain↗
PubMed1978

Computed tomography in the evaluation of subdural hematomas.

Computed tomographic (CT) scans used in the diagnosis and management of subdural hematomas were analyzed with respect to their contribution to angiography and surgery. There has been a progressive increase in the use of CT in evaluating post-traumatic and postoperative subdural hematomas at the Mayo Clinic. At present, 40% of all patients undergo operation on the basis of the CT findings alone. False-positive diagnoses revealed at surgery have decreased to less than 4%. Erroneous negative interpretations have involved 10% of all patients whose diagnosis was subdural hematoma. Criteria for the interpretation of scans have been established.

Brain↗
PubMed1978

Computed tomography and radionuclide imaging in the evaluation of ischemic stroke.

One hundred forty-one patients with cerebral or cerebellar infarction were examined by computed tomography (CT) as soon after the ictus as possible. The examination was repeated in 7 days, and a radionuclide brain scan was performed. The overall detection rate for ischemic infarction was approximately equal for both techniques, ranging from 58% for radionuclide scanning to 66% for the delayed CT. Almost half of the supratentorial infarcts examined by CT on the day of the ictus were demonstrated. Mass effect was observed as early as the first day and as late as the 25th day.

Adolescent↗
PubMed1978

Symptoms, findings, and methods of diagnosis in patients with acoustic neuroma.

The records of 225 patients with surgically documented acoustic neuromas seen at the Mayo Clinic between 1966 and 1976 were studied. Included in this group were 4 patients who had von Recklinghausen's disease with bilateral ear involvement, 7 patients with recurrence of acoustic neuroma, and 8 patients who were referred because of recurrent acoustic neuroma. Symptoms, clinical findings, and results of audiologic, vestibular, and roentgenographic studies were analyzed. Nine patients had a history of sudden onset of hearing loss, and 11 had a history of vertigo. A correlation between the size of the lesion and the symptoms, physical findings, and roentgenographic accuracy was made in an attempt to gain further knowledge of the natural course of the pathologic processes involved.

Adolescent↗
PubMed1978

Ultrastructural changes in feline arterial endothelium following subarachnoid hemorrhage.

Scanning electron microscopy of feline basilar arterial endothelium 4 hours, and 1, 3,5, and 7 days after subarachnoid hemorrhage (SAH) showed longitudinal furrows that correlated with angiographically demonstrated vasospasm. These ridges persisted after fixation at physiological pressure, and probably reflected medial contraction with undulation of the underlying elastic lamina. No change in endothelial cell morphology or thrombogenesis was observed as long as 7 days after SAH. There is no evidence from this study to suggest that ischemia from vasospasm is a product of thromboembolism from damaged endothelial surfaces.

Animals↗
PubMed1977

Multicystic cerebral degeneration in neonatal herpes simplex virus encephalitis.

Typical herpetic papulovesicular skin lesions developed in an apparently normal infant at 12 days of age and were followed within 48 hours by signs and symptoms of acute encephalitis. Herpes simplex virus type 2 was cultured from the intact skin vesicles, and a fourfold increase in complement fixation titer to herpes simplex virus type 2 was found over the ensuing 24 days. The infant survived her acute illness, but was left with severe neurologic sequelae manifested as microcephaly with multicystic cerebral degeneration. The short-term and convalescent course is documented by serial, clinical, and EEG examinations, and the nature of the cerebral damage is demonstrated by computerized transaxial tomography.

Brain Diseases↗
PubMed1977

Pituitary apoplexy producing internal carotid artery occlusion. Case report.

The authors report a case of pituitary apoplexy occurring several hours after carotid angiography. The event was associated with stupor, focal headache, and left hemiparesis. Repeat angiography demonstrated intracranial occlusion of the right internal carotid artery. At surgery, a hemorrhagic pituitary adenoma was found to be compressing the internal carotid artery, and the removal of the tumor resulted in restoration of flow. The mechanism, presenting symptoms and signs, and treatment of pituitary apoplexy causing compression of a major vessel are discussed.

Aged↗
PubMed1977

Carotid endarterectomy: results, complications, and monitoring techniques.

A system of grouping patients according to preoperative evaluation of risk of carotid endaterectomy is presented. The primary complications of this surgical procedure were myocardial infarction and residual mild to severe neurologic deficit. Neurologically stable patients without medical or angiographically determined risk factors (group 1) have a risk of 1%. Neurologically stable patients without medical risk but with angiographically determined risks (group 2) have a risk of 2%. Neurologically stable patients with significant medical illness and with or without angiographically determined risks (group 3) have a risk of 7%, primarily related to cardiac disease. Neurologically unstable patients (group 4) have a 6% risk for a neurologic deficit. Current monitoring techniques using continuous electroencephalograms, cerebral blood flow measurements, and arterial stump pressure are considered. The prevention and management of complications are presented in some detail.

Adenosine Triphosphate↗
PubMed1976

Progressing stroke. Angiographic aspects.

Progressing strokes were noted in 17 of 256 patients who underwent surgery for atheromatous disease involving the internal carotid artery. This disorder was characterized by an active increase in the neurologic deficit during an 18- to 24-hour period. Although angiographic findings were neither specific for this type of cerebrovascular disease nor uniformly present, the angiography did indicate that not only embolization of the cerebral leptomeningeal conducting vessels but also collaterization through them was a pertinent mechanism.

Aged↗
PubMed1976

Computed tomography in the diagnosis of posterior fossa lesions.

A series of 3,500 cases examined by computed tomography (CT) of the head were reviewed to identify patients who had symptoms and signs suggestive of neurologic disease in the posterior fossa. Three hundred forty eight such cases (about 10%) were found, and the scans were reviewed to determine the character of lesions that could be detected and the accuracy of the neuroradiologic diagnosis. Overall, 16 errors were made (4.6%), of which 13 were false negatives and 3 were false positives. False negatives included nine tumors, two infarcts, and two arteriovenous malformations. Four of the tumors and the two arteriovenous malformations were small and caused no visible alterations in density even when analyzed retrospectively. In the remaining seven cases, specific findings either were overlooked or were obscured by artifacts, and, therefore, the diagnosis was not made. The three false positive diagnoses were made through a misinterpretation of density changes that were artifactual. No changes in the intracranial absorption coefficients were detected in 109 cases. Abnormal changes were evident in 226 cases in which structural lesions were subsequently found. Many of the lesions had a characteristic appearance, but in certain clinical situations, which include searches for metastatic disease, acoustic neuromas, meningiomas aneurysms of the basilar artery, and arteriovenous malformations, the injection of intravenous contrast medium was helpful, or even essential, for diagnostic success. The prominence of clinical signs and symptoms is not always an accurate index to the presence of structural alteration of the posterior fossa. We believe, therefore, that this portion of the cranium should be included in every CT study.

Adolescent↗
PubMed1976

Bypass surgery for vascular disease of the carotid system.

A series of 58 operations on 56 patients, in whom a branch of the superficial temporal artery was anastomosed to a branch of the middle cerebral artery (STA-MCA bypass or Yasargil procedure), is reviewed. These operations were performed chiefly for occlussions or for inaccessible stenotic lesions of the internal carotid or middle cerebral arteries. Patency in eight patients operated on from April 1971 through November 1973 was low (25%). Patency in patients operated on since July 1974 has been high (95%). There have been no deaths and no major ischemic strokes attributable to the surgery. The rationale for this procedure is considered in relationship to the anatomy and physiology of the cerebral circulation and the pathogenesis of syndromes of cerebral ischemia. The operation appears to have a low morbidity in good-risk patients. The role of this operation in managing common manifestations of cerebral vascular disease such as focal transient cerebral ischemic attacks (TIAs) and amaurosis fugax, although not fully established, appears encouraging. The procedure seems useful for orthostatic cerebral ischemia caused by multiple occlusions of major extracranial (and intracranial) vessels and, occasionally, for progressing strokes related to internal carotid artery occlusion, both of which are relatively uncommon manifestations of cerebral vascular occlusive disease. It may have application in the rare "slow stroke." The procedure is probably of limited value, if any, in the management of large completed infarcts but may be indicated in selected patients with small infarctions who have preserved most of their cerebral function and who have had evidence of subsequent focal ischemic events. The procedure is useful for bypassing giant aneurysms or basofrontal tumors invading major vessels. It may have a role in the management of fibromuscular disease of the internal carotid artery.

Adult↗