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Biomedical subjects

H L Baker

Publications and source records attributed to H L Baker.

At least 19 recordsLinked to original sources
PubMed1991

Predictors of intracranial carotid artery atherosclerosis. Duration of cigarette smoking and hypertension are more powerful than serum lipid levels.

The effect of cigarette smoking on intracranial internal carotid artery atherosclerosis (ICAS) was studied by obtaining cigarette smoking histories and data on other potential predictors, including serum lipid estimations, for consecutive patients undergoing carotid arteriography. The duration of cigarette smoking was the most significant independent predictor of the presence of ICAS. Other independently significant predictors of ICAS were hypertension, diabetes mellitus, and current systolic blood pressure. The interaction of diabetes and duration of smoking was a significant negative predictor. In patients for whom serum lipid values were available, lower levels of apolipoprotein A-I were associated with a higher risk of having ICAS. However, the effect of apolipoprotein A-I as a predictor of the presence of ICAS was far outweighted by the effects of duration of smoking and hypertension.

Adult↗
PubMed1991

Serum lipids and lipoproteins are less powerful predictors of extracranial carotid artery atherosclerosis than are cigarette smoking and hypertension.

The effect of serum lipids and lipoproteins on extracranial carotid artery atherosclerosis (CAS) was studied in patients who underwent carotid arteriography. Serum lipid and lipoprotein values along with data on other potential predictors of extracranial CAS were determined in 240 patients who had at least one extracranial carotid artery visualized. In a multiple logistic regression analysis, the independently significant predictors of the presence of extracranial CAS were, in decreasing order of significance, duration of smoking of cigarettes, hypertension, age, and low-density lipoprotein cholesterol. Serum cholesterol, triglycerides, high-density lipoprotein cholesterol, and apolipoprotein A-I did not show an independent effect. Although low-density lipoprotein cholesterol was an independent predictor of the presence of extracranial CAS, its effect as a predictor was far outweighed by the effects of the duration of smoking of cigarettes and a history of hypertension.

Adult↗
PubMed1990

Duration of cigarette smoking is the strongest predictor of severe extracranial carotid artery atherosclerosis.

The effect of cigarette smoking on extracranial carotid atherosclerosis was studies by obtaining cigarette smoking histories and information on other potential risk factors from consecutive patients undergoing carotid arteriography. At least on extracranial carotid artery was visualized in 752 patients in whom the extent of carotid atherosclerosis was assessed. The total years of cigarette smoking was the most significant independent predictor of the presence of severe carotid atherosclerosis. Other independent predictors, in order of significance, were age, hypertension, diabetes mellitus, male sex, and current systolic blood pressure. By age 60 years, the risk of having severe carotid atherosclerosis for a person who had smoked for 40 years was approximately 3.5 times that for a never smoker. The major benefit of smoking cessation is in limiting the accumulation of smoking years.

Age Factors↗
PubMed1989

Predictive value of carotid bruit for carotid atherosclerosis.

To assess the predictive value of carotid bruit for moderate-to-severe carotid atherosclerosis, the results of carotid arteriograms performed on 1004 subjects were correlated with the findings of auscultation of the carotid arteries. Predictive values of carotid bruit for ipsilateral extracranial carotid atherosclerosis were 77% for localized bruits and 74% for diffuse bruits. The predictive values of extracranial carotid bruit for ipsilateral intracranial carotid atherosclerosis were 16% for localized bruits and 18% for diffuse bruits. Assessing both carotid arteries together, the predictive value of carotid bruit for moderate-to-severe atherosclerosis at any extracranial carotid site was 85%, there being no difference whether the bruits were diffuse, localized, bilateral, or unilateral. Diffuse or localized bruits, whether unilateral or bilateral, are equally predictive of moderate-to-severe atherosclerosis in the extracranial carotid artery, but both are poor predictors of intracranial carotid artery disease.

Adult↗
PubMed1989

Spinal cord sarcoidosis: a new finding at MR imaging with Gd-DTPA enhancement.

Three patients with histologically confirmed sarcoidosis with spinal cord involvement were examined with high-field-strength magnetic resonance imaging (1.5 T) before and after the administration of gadolinium diethylenetriaminepentaacetic acid. In addition to intramedullary expansion, areas of patchy, multifocal, parenchymal enhancement and areas of linear peripheral enhancement were seen in all three patients; these findings have not been previously reported and are unusual for other more common spinal cord lesions. This observation led to a correct diagnosis and a limitation of the extent of biopsy in two of the cases. Unfortunately, this enhancement pattern is not specific for sarcoidosis, as the authors have observed similar findings in two cases of biopsy-proved myelitis and multiple sclerosis. The peripheral enhancement is thought to be located in the leptomeninges due to leptomeningeal involvement, which was proved histologically in one case. This pattern of involvement, while not specific, is certainly consistent with and, in the appropriate clinical setting, highly suggestive of sarcoidosis.

Adult↗
PubMed1989

Anatomical and profile analysis of the female black American nose.

An anatomical and anthropometric study was conducted that compared nasal pyramid measurements of Negroid with Caucasian skulls and surface measurements of black with Caucasian controls. Eight external surface measurements were used to develop a classification system to show the range of the female black American nose. This classification will be described along with the range of measurements on which it is based. This classification may provide a better understanding of the anatomic characteristics of the normal variation of Negroid noses, and thus improve the surgeon's ability to evaluate black patients for rhinoplasty.

Adult↗
PubMed1988

Central pontine myelinolysis and its imitators: MR findings.

The clinical, radiologic, and neuropathologic findings in 13 patients with central pontine myelinolysis were reviewed. Antemortem computed tomography (CT) had been performed in nine, and ante- or postmortem magnetic resonance (MR) imaging in 11. Chronic alcoholism or rapid correction of hyponatremia was present in over 75% of cases. One CT scan was positive, but only on retrospective review. In all but one patient, MR imaging eventually revealed an abnormality within the pons; in two patients the initial study was normal. The lesions varied in shape, with peripheral involvement in two patients and extrapontine involvement in four. The abnormality was smaller at 6-month follow-up in one patient and unchanged at 1 year in another. One patient never had a demonstrable pontine lesion but did have symmetric basal ganglia abnormalities, which were consistent with extrapontine myelinolysis. MR imaging disclosed similar central pontine alterations resulting from infarct, metastasis, glioma, multiple sclerosis, encephalitis, and radiation or chemotherapy; thus, such changes are not unique.

Adult↗
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

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

Glomus tympanicum chemodectomas: radiographic and clinical characteristics.

Glomus tympanicum chemodectomas are benign neoplasms that develop from normal glomus bodies located along the Jacobson (tympanic) nerve in the middle ear. The medical charts and radiographic studies of 55 patients with these tumors were reviewed. Women outnumbered men in a ratio of 3.5:1, and the patients' average age when they initially reported symptoms was 52 years. Tinnitus, ear pulsations, and diminished hearing were the most frequent symptoms. No patient had a second chemodectoma, and none of seven patients who were tested had elevated neuroendocrine compounds. Review of the radiographic examinations showed that direct coronal, thin-section computed tomography (CT) was the most sensitive means of demonstrating glomus tympanicum chemodectomas. Magnification angiography was also a sensitive diagnostic study, typically depicting a trapezoidal, hypervascular, middle-ear mass that appeared initially in the middle-to-late arterial phase and quickly disappeared in the venous phase. Differentiation from an aberrant internal carotid artery is critical to prevent arterial biopsy.

Adult↗
PubMed1986

The application of magnetic resonance imaging in otolaryngology.

Magnetic resonance imaging is a new diagnostic technique that is being applied to study disease processes that involve the upper aerodigestive tract and cranial nerves of interest to otolaryngologists. As with all imaging techniques, an in-depth knowledge of the normal anatomy of a region is a prerequisite for the appreciation of disease states. In addition, magnetic resonance imaging requires a familiarity with the signal intensity produced by the different structures and the relationship of that signal to various radiofrequency pulse sequences that may be used. This report briefly reviews the techniques of magnetic resonance imaging and the normal anatomy of the cervical region and presents examples of pathologic processes that have been studied with this powerful diagnostic technique.

Ear↗
PubMed1986

Correlation of radiological features to failure of lumbar intervertebral disc chemonucleolysis.

Chemonucleolysis was performed in 103 patients for lumbar disc prolapse. Multiple (two) interspaces were injected in only seven patients. Radiographically, all patients had myelographic or computerized tomography evidence of disc prolapse. Eighty-seven of 100 patients who were available for follow-up review had improved. Ten of 13 patients with persistent symptoms required a laminectomy. Altered spinal alignment was evident in five of the 13 patients with persistent symptoms: retrolisthesis in three and myelographic disc defect on the convex aspect of the scoliosis in two. Review of radiographic studies was carried out in an attempt to establish guidelines for patient selection so as to decrease the rate of failure in chymopapain treatment.

Adolescent↗
PubMed1985

Magnetic resonance imaging in a routine clinical setting.

The results of magnetic resonance imaging (MRI) examinations in the first 1,000 consecutive patients who were studied by this technique at our institution were reviewed to determine the disease states encountered, the sensitivity and accuracy of results, and the value of the examination as compared with computed tomography and other imaging procedures. The MRI device was a 0.15-tesla resistive magnet that used a variety of saturation recovery, spin echo, and inversion recovery pulse sequences to produce images. MRI was found equal to or superior to other imaging techniques in most cases. Exceptions included organs or body regions that are prone to excessive respiratory or vascular motion, lesions that necessitate exquisite spatial resolution for diagnosis, and lesions in which angulation of the viewing plane is necessary for optimal depiction. Fresh blood and calcification within a lesion were also difficult to detect with use of MRI.

Adolescent↗
PubMed1985

Magnetic resonance imaging in syringomyelia.

Myelography and myelography assisted with computed tomography have been the most commonly used radiographic methods in the study of syringomyelia. These studies have never been entirely reliable in demonstrating the syrinx cavity and its relationship to other intracranial structures. During the 1st year of operation of the magnetic resonance imaging facility, the syringomyelic cavity was demonstrated in 15 patients who all had typical clinical signs and symptoms associated with syringomyelia. Nine cases were syringomyelia with Chiari malformation. One case showed additional hydrocephalus. Four cases were idiopathic, and 1 case was remotely posttraumatic. Magnetic resonance imaging, although it is in its infancy, already promises to be the most important radiographic technique for syringomyelia because it provides an anatomically truthful visualization of the sagittal plane of the cervical cord and can demonstrate the syrinx cavity and its relationship with the cerebellar tonsils, the 4th ventricle, and other related structures.

Adolescent↗
PubMed1985

CT of the sella turcica after transsphenoidal resection of pituitary adenomas.

A retrospective review of 120 patients undergoing transsphenoidal surgery for pituitary adenomas revealed that computed tomography (CT) was less sensitive and less specific than hormonal methods in identifying residual functioning adenomas. However, CT was the only useful method of evaluating nonfunctioning tumors, including pseudo-prolactinomas. Enlargement of the pituitary stalk, when seen on preoperative CT, was 100% predictive of "cure" if the enlargement returned to normal size on a remote follow-up scan (n = 8) and was 100% predictive of residual tumor if the enlargement persisted or evolved (n = 8). Resolution of stalk displacement was the next most reliable predictor of cure (91%, n = 11), but persistent displacement was less reliable than abnormal intrasellar enhancement in predicting the presence of residual tumor (71%, n = 28, vs. 81%, n = 26). Enhancement in the postoperative sella by other than normal pituitary gland was presumed to be due to inflammation in 19% of patients. Inflammatory enhancement was observed in the presence of autograft and homograft muscle plugs and, unlike enhancement due to untreated tumors, was observed to decrease in size and intensity with time. Intrasellar enhancement was an unreliable criterion of success or failure in cases of microadenoma. All 14 patients with functioning adenomas and preoperative parasellar tumor extension had persistent tumor at postoperative evaluation. Of the 47 patients with resected functioning adenomas who had CT scans showing empty or partly empty sellas after operation, 22 (47%) had hormonally detectable residual tumor.

Adenoma↗