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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↗
PubMed1991

Iopamidol myelography: morbidity in patients with previous intolerance to iodine derivatives.

The records of 1005 patients who underwent iopamidol myelography between January and September, 1988, were reviewed. In this group, 50 patients had histories suggestive of untoward sequelae associated with iodine intake, contact, or administration. The charts of these patients were carefully reviewed, and none of them had any reactions or sequelae suggestive of toxicity or an allergic response after iopamidol myelography. It is concluded that, even in patients with a previous history suggestive of intolerance to iodine administration, iopamidol myelography is generally a safe procedure.

Adolescent↗
PubMed1990

Prospective study of the effectiveness and durability of carotid endarterectomy.

In a series of 252 consecutive patients who underwent 282 carotid endarterectomies, we conducted clinical and angiographic follow-up for 2 to 6 years (mean, 3.2 years). Digital subtraction angiography (DSA) was done postoperatively in 95% of cases. Clinical follow-up was achieved in 97% of cases, and DSA follow-up was obtained in 66% of cases. The overall group had a 1% operative minor morbidity (three cases of minimal new neurologic deficit), no major morbidity, and a 0.7% mortality (one death from stroke and one from myocardial infarction). Complications correlated well with the patient's preoperative risk category. During follow-up, 10 minor strokes, only 1 of which was attributable to the reconstructed artery, and 10 transient ischemic attacks, 3 of which were presumably related to recurrent stenosis, occurred. Asymptomatic mild to moderate restenosis of the internal carotid or common carotid artery was identified in 10% of follow-up DSAs and severe stenosis or occlusion in 3%. Stenosis in the opposite common carotid or internal carotid artery progressed in 48 cases (26% of follow-up DSAs and ultrasound studies), and 10 of these became symptomatic. An actuarial analysis of patients who had endarterectomy indicated that the cumulative probability of ipsilateral stroke was 1.5% at 1 month and 2% at 5 years. The cumulative probability of ipsilateral stroke, transient ischemic attack, or reversible ischemic neurologic deficit was 4% at 1 month and 8% at 5 years or less than 1% per year after the first month, with censoring at the time of the second surgical procedure.

Actuarial Analysis↗
PubMed1989

Brief loss of consciousness in bilateral carotid occlusive disease.

Loss of consciousness is rare in the absence of transient or persistent insult to the diencephalon or mesencephalon. We found three patients with severe atherosclerotic stenosis or occlusion of both internal carotid arteries who experienced brief loss of consciousness. Common characteristics were the absence of clinical or electroencephalographic seizure activities, significant cardiovascular disease, or a history suggestive of vasovagal syncope. Angiographically, the patients had widely patent vertebrobasilar circulation and collaterals from vertebrobasilar to carotid circulation. Episodic loss of consciousness disappeared after carotid endarterectomy. We concluded that bilateral hemispheric ischemia caused brief loss of consciousness, but selective focal ischemia in the subcortical structures superimposed on widespread bihemispheric ischemia may have been responsible. Since loss of consciousness is rare in carotid occlusive diseases, systemic and vertebrobasilar causes must be carefully ruled out in each instance.

Aged↗
PubMed1989

Arterio-inferior sagittal sinus fistulae: case report.

The management of the case of a 9-year-old boy with progressive cognitive impairment due to arteriovenous fistulae at the apex of the inferior sagittal sinus is reported. This represents a unique location for an extraparenchymal deep central arteriovenous malformation. The patient underwent staged ablation of the lesion by surgery. The postoperative course was complicated by expansion of an aneurysmal vein of Galen undergoing thrombosis and hyperperfusion syndrome, but the patient ultimately made a satisfactory recovery.

Arteriovenous Fistula↗
PubMed1989

Cerebral tuberous sclerosis: MR imaging.

Nineteen patients with a clinical diagnosis of tuberous sclerosis were examined with high-field-strength magnetic resonance (MR) imaging. Their ages ranged from 6 months to 12 years. In 17 cases, the MR examinations showed both subependymal nodules and multiple peripheral gyral lesions consistent with cortical tubers. Cortical tubers were more frequently demonstrated on spin-echo images obtained with a long repetition time (TR). Because the signal abnormality was located predominantly in the subcortical portion of the tubers, the terms "gyral core" and "sulcal island" were used to describe the patterns noted at MR imaging. Subependymal nodules were best seen on inversion-recovery or short TR spin-echo images, although hypointensity within the nodules consistent with calcification was present in 14 patients and was most evident on long TR spin-echo images. Computed tomographic (CT) scans that had been obtained within 3 years of MR images were available for 13 patients. Intracranial calcification was more accurately diagnosed with CT. However, MR imaging is more sensitive than CT in the detection of gyral tubers and, thus, may be better for screening family members and others in whom tuberous sclerosis is a possibility.

Brain↗
PubMed1989

Angiographic frequency of anterior circulation intracranial aneurysms.

A retrospective angiographic analysis was designed to extrapolate the frequency of angiographically defined asymptomatic intracranial aneurysms in the anterior circulation from a relatively unbiased clinical series. A total of 9295 angiograms were reviewed from January, 1980, to January, 1987, and, based on these, 278 patients with minimal bias for the presence of an aneurysm were selected. Three patients were found to have incidental aneurysms; thus, the angiographic frequency of patients with asymptomatic aneurysms in this series was 1%. This patient population is skewed toward the older age groups and probably over-represents the incidence of these aneurysms in the population at large. Comparing current subarachnoid hemorrhage statistics and the low frequency of asymptomatic aneurysms suggests that a larger percentage of these aneurysms than was previously thought subsequently rupture. This study contrasts sharply with previous reports quoting a high incidence of aneurysms, and significantly alters the concept and treatment of this disease.

Adolescent↗
PubMed1988

Spontaneous dissections of the vertebral arteries.

Clinical and angiographic features and outcome in 25 patients with spontaneous dissections of the vertebral arteries are described. Most patients were in their fourth or fifth decade of life, and women predominated. Forty-eight percent of the patients were hypertensive. Angiographic evidence of fibromuscular dysplasia was noted in one only. Brainstem ischemic symptoms (usually a lateral medullary syndrome) and ipsilateral occipital headache and neck pain (often preceding but sometimes associated with or following the brainstem ischemic event) were the most common clinical findings. The angiographic features in decreasing order of frequency were luminal stenosis (often irregular and tapered), aneurysm, occlusion, and intimal flap. On follow-up, most of the patients (88%) made complete or very good recoveries. Angiographic abnormalities either subsided or improved in 76%. Multivessel dissection (involvement of both vertebral arteries or one or both vertebral arteries and one or both internal carotid arteries) was noted in about two-thirds of the patients. This tendency of vertebral artery dissections to involve multiple cervicocephalic vessels concurrently, if not simultaneously, implies that four-vessel angiography should be attempted if a vertebral artery dissection is visualized. It also raises the possibility of an underlying arteriopathy that predisposes the vessel to dissection.

Adult↗
PubMed1988

Comparison of magnetic resonance imaging and computed tomography in the preoperative evaluation of pituitary adenomas.

Twenty surgically verified pituitary adenomas were imaged in a systematic comparative fashion with high field strength magnetic resonance imaging (MRI) and computed tomography (CT) before operation. The study group included 11 microadenomas, 4 macroadenomas, 2 recurrent microadenomas, and 3 recurrent macroadenomas. The MRI and CT examinations were evaluated for lesion detection, pituitary stalk displacement, cavernous sinus displacement or invasion, hemorrhage, cystic degeneration within the adenoma, bony erosion, detection of suprasellar extension, and displacement of suprasellar structures. T1 and T2 relaxation characteristics of the adenomas were evaluated on MRI examinations, and contrast enhancement characteristics were evaluated on CT examinations. MRI was superior to CT for detecting the extrasellar extent of tumor. Within the sella turcica, MRI and CT were equivalent with regard to lesion detection, except for 1 patient in whom CT was able to detect a surgically confirmed 3-mm microadenoma that was not visualized on the MRI examination.

Adenoma↗
PubMed1988

Traumatic dissections of the extracranial internal carotid artery.

Traumatic dissections of the extracranial internal carotid artery (ICA) in 18 patients aged 19 to 55 years were studied. All had suffered blunt head or neck injury of marked or moderate severity; motor-vehicle accidents were the leading cause of the injury. Delayed focal cerebral ischemic symptoms were the most common presenting symptoms. Less commonly noted was focal unilateral headache associated with oculosympathetic paresis or bruit. Following a head injury, the abrupt onset of focal cerebral symptoms after a lucid interval should raise the suspicion of arterial injury, particularly when computerized tomography fails to show abnormalities that would explain the evolving neurological deficits on the basis of direct trauma to the brain. Unilateral headaches, oculosympathetic palsy, and bruits also help in establishing the diagnosis. Focal cerebral ischemic symptoms may develop months or years after the initial trauma. These delayed symptoms are caused by embolization from a thrombus within a residual dissecting aneurysm. Common angiographic findings, in decreasing order of frequency, are: aneurysm, stenosis of the lumen, occlusion, intimal flap, distal branch occlusion (embolization), and slow ICA-to-middle cerebral artery flow. Although two patients died as the result of massive cerebral infarction and edema and some were left with severe neurological deficits, most made a good recovery. Residual dissecting aneurysms and occlusion seem to occur more frequently with traumatic dissections than with spontaneous dissections of the extracranial ICA.

Adult↗
PubMed1987

Trapped fourth ventricle in an adult: radiographic findings and surgical treatment.

Trapped fourth ventricle is a rare entity that has most often been reported mainly in children as a late complication of lateral ventricle shunting. We report a case in a previously normal adult who developed symptoms several months after bacterial meningitis. Unique radiographic and surgical findings are discussed, and recommendations are made for the classification and treatment of fourth ventricular enlargement.

Cerebral Ventricles↗
PubMed1987

Magnetic resonance imaging and clinical relationships in multiple sclerosis.

Magnetic resonance imaging (MRI) was done in 109 patients with suspected demyelinating disease (56 with clinical multiple sclerosis [MS] and 53 without). Of those with clinical MS, 43 (77%) had multifocal lesions of the white matter detected on MRI; 12 of the 43 also had confluent periventricular signaling. Nine patients (17%) without clinical MS had similar findings. Of the 56 patients with MS, 35 underwent both computed tomography (CT) and MRI. In this group, 80% of MRI scans showed multiple demyelinating lesions compatible with MS, as compared with 29% of the CT scans. A CT scan was "positive" more often if obtained within 1 month after an attack of MS than later. In contrast, the sensitivity of MRI or the number of lesions detected by MRI did not increase in patients with recent exacerbations. MRI was "positive" in patients with clinical MS more often than was any single evoked response study. In statistical analyses, both the sensitivity of MRI and the number of lesions were associated with the duration of MS. A pattern of confluent periventricular signaling around the lateral ventricle was associated with greater duration of MS and patient disability.

Adult↗
PubMed1987

Imaging of cranial chordomas.

The clinical, pathologic, and imaging characteristics of clival chordomas in 14 patients who underwent magnetic resonance examinations were evaluated. Magnetic resonance imaging (MRI) was compared with skull series, tomography, computed tomography (CT), and magnification angiography in the diagnosis of clival chordomas. Although all examinations were highly sensitive for the detection of clival chordomas, MRI was the best single study because of its ability to image in orthogonal planes, its excellent soft-tissue contrast, and its demonstration of the relationship between the neoplasm and regional vital structures, particularly the brainstem, cavernous sinus, cranial nerves, and neighboring vessels. The deficiencies of MRI are poor visualization of tumoral calcification and osseous destruction--findings that are better identified on CT. In all 14 cases, MRI revealed the neoplasms to be black on inversion-recovery, gray on partial-saturation, and white on T2-weighted pulse sequences. Three chordomas had a speckled signal void pattern, typical of tumor calcification.

Adolescent↗
PubMed1987

Arterial fibromuscular dysplasia.

Fibromuscular dysplasia is a nonatherosclerotic, noninflammatory vascular disease that involves primarily the renal and internal carotid arteries and less often the vertebral, iliac, subclavian, and visceral arteries. Although its pathogenesis is not completely understood, humoral, mechanical, and genetic factors as well as mural ischemia may play a role. The natural history is relatively benign, with progression occurring in only a minority of the patients. Typical clinical manifestations are renovascular hypertension, stroke, subarachnoid hemorrhage, abdominal angina, or claudication of the legs or arms. In patients with symptoms, percutaneous transluminal angioplasty has emerged as the treatment of choice in most involved vascular beds.

Arterial Occlusive Diseases↗
PubMed1987

Elevation of serum creatine kinase B-subunit levels by radiographic contrast agents in patients with neurologic disorders.

The effect of radiographic contrast agents on the central nervous system was evaluated by measurement of serum creatine kinase B-subunit (CKB) levels with use of radioimmunoassay in 58 patients who underwent computed tomographic (CT) scanning and 46 patients who underwent cerebral angiography for evaluation of cerebrovascular diseases, brain tumors, and other neurologic disorders. In 11 patients (10.6%), the CKB increased to abnormally high levels within 4 hours after the radiographic procedures, and the median value after 30 minutes was significantly higher than the corresponding precontrast value (P less than 0.01). Eight of the 11 patients had recent ischemic cerebrovascular diseases, and 7 of the 11 had undergone CT scanning. On the basis of the information available in the literature, elevation of the serum CKB levels may be interpreted as reflecting breakdown of the blood-brain barrier and neural damage. Intravascularly administered radiographic media are generally safe, but the results of the current investigation suggested the potential for detrimental effects, particularly in patients with recent cerebrovascular diseases.

Brain↗
PubMed1987

Primary spinal melanoma.

The records of five patients with primary melanoma of the spinal cord were reviewed. The tumor most frequently presented as an intramedullary middle or lower thoracic cord lesion. The average duration of symptoms before pathological diagnosis was 29 months, and the average survival after laminectomy and radiation therapy was 6 years 7 months. The findings in this series, when compared with those in the literature, suggest that primary spinal melanoma is a more indolent malignancy than previously reported or than melanoma metastatic to the central nervous system.

Aged↗