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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
PubMed1997

Cortical tuber count: a biomarker indicating neurologic severity of tuberous sclerosis complex.

The relationship between the number of cortical tubers observed by magnetic resonance imaging (MRI) and the severity of cerebral dysfunction of tuberous sclerosis patients has been examined in a meta-analysis of the published literature. The literature review has identified five independent studies for examining the association. These studies consistently reveal that the cortical tuber count detected on MRI scans is increased among those with more severe cerebral disease. Severity of the cerebral dysfunction is measured by the seizure status and its control and by the developmental status and the level of mental retardation. Meta-analysis demonstrates that within a study population, the MRI-detected cortical tuber count is six times more likely to be above the median count for tuberous sclerosis patients with severe cerebral dysfunction (poor seizure control or moderate-severe retardation or both) than more mildly affected tuberous sclerosis patients. Similarly, across studies, moderately to severely affected patients are five times more likely to have greater than seven MRI-detected cortical tubers than those more mildly affected. These associations are both statistically significant and strong. The cortical tuber count is a biomarker that reasonably predicts the severity of cerebral dysfunction of tuberous sclerosis. Cortical tubers of tuberous sclerosis form in the early gestational period. The embryologic disruption determining the clinical severity of the cortical dysfunction of tuberous sclerosis is set in the early gestational period.

Cerebral Cortex↗
PubMed1997

Sarcoidosis presenting as a central nervous system mass lesion.

Neurosarcoidosis occurs in approximately 5% of patients with systemic sarcoidosis. A review of medical literature shows that intracranial mass-like lesions secondary to sarcoidosis are quite rare. CT and MRI scanning would suggest that this manifestation of neurosarcoidosis may be more common than previously realized. We discuss five cases of neurosarcoidosis presenting as an intracranial mass. Empiric corticosteroid treatment can be recommended for cases with CNS mass in the context of systemic sarcoidosis.

Adult↗
PubMed1995

Cervical disk prolapse.

OBJECTIVE: To correlate the findings on computed tomographic myelography (CTM) with surgically and pathologically proven prolapsed cervical disks, mention other pertinent cross-sectional imaging studies, and note the clinical relevance of certain CTM features. DESIGN: We retrospectively reviewed the medical and radiologic records of Mayo patients with suspected degenerative cervical disk disease during a 4-year period. MATERIAL AND METHODS: Between January 1986 and December 1989, 734 patients with possible cervical disk disease underwent assessment by CTM. An extruded disk was noted in 297 of these patients. In this study group, magnetic resonance (MR) imaging was also done in 28 patients and plain computed tomography was performed in 14, and we summarized those findings. RESULTS: Of the 297 study patients, 280 had a cervical radiculopathy and 17 had a myelopathy. CTM identified more than 90% of the extruded cervical disks. CTM could not distinguish between an osteophytic cartilaginous cap and a disk, and CTM could not identify the source of a cervical radiculopathy in 102 patients. Although only a few imaging studies other than CTM were performed, those modalities were less sensitive in the detection of prolapsed disks. CONCLUSION: Imaging of cervical disk prolapse continues to be difficult, and the results are not always specific. CTM is the most sensitive imaging examination, but the number of MR studies in the current series of patients was insufficient for a reasonable comparison between the two modalities.

Adult↗
PubMed1995

MR findings in tuberous sclerosis complex and correlation with seizure development and mental impairment.

PURPOSE: To correlate the findings on MR scans of the brain in patients with tuberous sclerosis complex with mental disability and the type and age at onset of the first seizure. METHODS: Patients with tuberous sclerosis complex who had MR brain scans were identified. The diagnosis was confirmed, and the clinical information on each patient was updated. The number, site, and area of abnormal signals were recorded on each scan. The presence of sulcal islands, gyral cores, and migration lines or wedges was recorded. RESULTS: Seventy-five patients were studied. Twenty-nine patients who had infantile spasms had more tubers than the 26 who presented with other types of generalized seizures. These patients had more tubers than the 15 patients with partial seizures. Significantly more tubers were found in patients with seizure onset before 1 year of age and mental disability. Gyral cores, sulcal islands, and radial migration lines or wedges were more common in patients with infantile spasms who had an early seizure onset and were mentally disabled. Patients who did not have seizures had no mental disability. CONCLUSIONS: A greater number of tubers occurred in patients who had infantile spasms, had their first seizure before 1 year of age, or had a mental disability. These features reflect the degree of cerebral dysfunction caused by the tubers. Gyral cores, sulcal islands, and migration lines or wedges also reflect cerebral dysfunction. MR scans correlate well with the clinical features and are valuable in assessing patients with tuberous sclerosis complex.

Age of Onset↗
PubMed1994

Cervical spondylotic stenosis and myelopathy: evaluation with computed tomographic myelography.

OBJECTIVE: To determine which components of cervical spondylosis are most frequently present in patients with myelopathy. DESIGN: We reviewed the findings in 93 patients who underwent surgical decompression for cervical spondylotic myelopathy between January 1986 and December 1989 at Mayo Clinic Rochester. MATERIAL AND METHODS: All 93 patients (72 men and 21 women) underwent computed tomographic (CT) myelography. In addition, magnetic resonance imaging scans were available in 25 patients, and plain CT scans were obtained in 2. RESULTS: A review of CT myelograms revealed that all neurocompressive intraspinal spondylotic changes were reflected in the shape of the spinal cord. Among the 93 patients with myelopathy, the configuration of the spinal cord could be categorized into primarily three dominant types: A (severe encroachment that compressed the cord into the shape of a banana; N = 40), B (moderate encroachment that produced less prominent compression; N = 23), and C (moderate bilateral uncovertebral spurs; N = 12). As a comparison group, 30 patients with similar spinal cord deformities but without progressive myelopathy were analyzed. Correlation of the two groups showed that myelopathy was present in up to 98% of patients with type A spinal cord, in 75% with type B, and in 71% with type C. The findings on magnetic resonance imaging were similar to those on CT myelography, but the bony spondylotic components were less readily seen. CONCLUSION: The precise pathophysiologic mechanism of myelopathy in spondylosis remains an enigma. Although the bulk of the data on our patients supports direct compression, we believe that the cause is multifactorial.

Adult↗
PubMed1994

Angiographically occult vascular malformations: a correlative study of features on magnetic resonance imaging and histological examination.

With reference to vascular malformations, the term cavernous has architectural as well as histologic connotations. It refers to a compact pattern of growth wherein no intervening brain parenchyma is evident, as well as to the histological nature of the vessels, which are hyaline and collagenous in appearance, lacking the microscopic features of arteries or veins. Historically, cavernous angioma has been defined as exhibiting both features. Twenty-five patients with neurological symptoms and neuroimaging abnormalities who underwent surgery for cerebral vascular malformations between 1987 and 1990 satisfied the following study criteria: their lesions were angiographically occult and both magnetic resonance imaging (MRI) and histological sections were available for review. The patients' ages ranged from 4 to 49 years (mean, 30 years), the male to female ratio being 1:2. Two thirds of the lesions were supratentorial in location and all were intraparenchymal. All patients had clinical improvement after resection. In 24 of the 25 lesions, the vascular channels were histologically cavernous in nature; one inadequate specimen precluded classification. Three demonstrated a purely compact or cavernous pattern, 20 a mixed cavernous and racemose pattern, and one a purely racemose pattern. The authors conclude that 1) histologically cavernous lesions are the commonest form of occult vascular malformation; 2) a purely compact or cavernous architectural pattern is uncommon, most lesions showing a partially racemose architecture; 3) some histologically cavernous malformations possess a capillary component; 4) clinical growth of cavernous malformations may have its basis in intraluminal thrombosis and subsequent recanalization; 5) the T2-weighted MRI pattern of cavernous malformations varies, the most common being a multifocal hyperintense center surrounded by a hypointense ring; 6) the MRI pattern reflects the histological appearance; 7) since no thrombosed arteriovenous malformations were encountered, such lesions must be rare; 8) in that the pathophysiological hallmark of a cavernous lesion is recurrent thrombosis and hemorrhage, a resolving hematoma cannot always be distinguished from a cavernous lesion; 9) MRI is the examination of choice in evaluating occult vascular malformations; and 10) microsurgical excision is a satisfactory method of treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Actins↗
PubMed1993

Cervical neural foraminal canal stenosis: computerized tomographic myelography diagnosis.

The surgical and computerized tomographic myelography (CTM) features of 134 stenotic foraminal canals were correlated retrospectively in 95 patients. The myelographic site of stenosis was the entrance to the foraminal canal in 70 cases (52%) and the canal itself in 37 (28%); the site was not identified definitively in 27 (20%). At the entrance to the foraminal canal, encroachment on the adjacent nerve root was by a cartilaginous cap in 10 cases (8%), a bony osteophyte in 17 (13%), a synovial cyst in one (1%), and a combination of a bony and cartilaginous osteophyte in 42 (31%). The diagnostic features of stenosis within the foraminal canal were more variable. Small bone spurs arising from the uncovertebral process encroached on the anterior aspect of the foramen in 29 instances (22%), accompanied in all cases by either a congenitally narrow canal (in 16) or a diffuse osteophytically narrowed canal (in 13); osteophytes arising from the superior facet in eight instances (6%) were larger and encroached on the posterior aspect of the foramen. Diagnosis on the basis of CTM is difficult because stenosis was readily evident as a bone spur in only 13% of cases, could not be distinguished from prolapsed disc in 39%, had to be differentiated from a congenitally narrow foraminal canal in 27%, and was frankly missed in 20% of the instances of stenosis.

Adult↗
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↗