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Biomedical subjects

W R Kinkel

Publications and source records attributed to W R Kinkel.

At least 37 records · Page 2Linked to original sources
PubMed1986

Nuclear magnetic resonance imaging in patients with stroke.

In contrast to CT, NMR imaging revealed a high percentage of abnormalities in the TIA-RIND population studied. The various patterns of abnormalities identified should provide further insight into the pathophysiology of ischemic cerebrovascular disease. Age and hypertension appeared to be the most significant clinical risk factors for TIA-RIND. Although periventricular hypodensities have been visualized by CT for many years, their clinical significance has only recently been appreciated. NMR shows the same periventricular changes as increased signal (long T2), but shows it in a more dramatic fashion. These periventricular abnormalities, seen both by CT and NMR, have been shown in some cases to be compatible with the pathologic diagnosis of SAE, or Binswanger's disease. Watershed abnormalities both with and without corresponding cerebral infarctions have been presented. At present, this appears to be a ubiquitous group of cerebrovascular disease with multiple underlying causes. NMR is superior to CT for demonstrating watershed infarctions, not only because it reveals ones missed by CT, but also because it shows a fuller extent of involvement than does CT. The evolution of cerebral infarctions as seen by CT and NMR has been presented. NMR demonstrates abnormalities earlier than CT. The region of infarction appears more extensive than by CT and chronic infarctions show an associated rim of prolonged T2 that may correspond to the ischemic penumbra or regions of ischemic demyelinization. CT phenomena, such as fogging and GME, have their NMR correlates. To date, all regions of GME shown by CT have also been demonstrated by NMR. Cortical infarctions, thought in many instances to be due to emboli have been frequently demonstrated by NMR. NMR imaging is clearly superior to CT for recognizing these lesions because it is not hampered by artifact from bone adjacent to cortex, as is CT. Similarly, posterior fossa and brainstem infarctions may be seen to advantage by NMR.

Aged↗
PubMed1986

Correlations of nuclear magnetic resonance imaging, computerized tomography, and clinical profiles in multiple sclerosis.

Nuclear magnetic resonance (NMR) imaging was superior to CT for imaging the brain lesions of 27 patients with MS. The incidence of abnormal examinations was 78% by NMR and 63% by CT. In cases in which both studies were abnormal, NMR usually demonstrated many more lesions and more extensive involvement than CT. The appearance and locations of lesions identified by NMR were similar to those of autopsy studies of MS and may be relatively specific for this disease. Some lesions identified by CT disappeared during serial examinations, but lesions identified by NMR did not resolve over time. Seventy-five percent of the lesions were clinically "silent"; only 5% were definitely related to the clinical symptoms and signs. All of those lesions were located in the brainstem or cerebellar peduncles and were identified by NMR, but missed by CT.

Adult↗
PubMed1985

Subcortical arteriosclerotic encephalopathy (Binswanger's disease). Computed tomographic, nuclear magnetic resonance, and clinical correlations.

Twenty-three elderly patients were found to have a consistent pattern of leukoencephalopathy by computed tomography and nuclear magnetic resonance imaging. Eight patients presented with vague, nonspecific symptoms and had no neurologic deficits. The other 15 patients had neurologic deficits that presented in one of three ways: stroke, seven patients; slowly progressive dementia and gait disturbance, five patients; or slowly progressive dementia alone, three patients. Risk factors for arteriosclerosis (hypertension, diabetes) were present in 18 patients (78%). The necropsy of one patient revealed arteriosclerotic vasculopathy characteristic of subcortical arteriosclerotic encephalopathy (SAE) or Binswanger's disease. Subcortical arteriosclerotic encephalopathy may be a relatively common affliction of elderly patients, most of whom have risk factors for arteriosclerosis. The modes of presentation and associated clinical signs are variable, and more than one third may have no neurologic deficit. In some cases SAE overlaps with normal pressure hydrocephalus by clinical and neuroimaging criteria. Some patients with normal pressure hydrocephalus who do not respond to ventricular shunting may actually have SAE.

Aged↗
PubMed1984

Altitudinal hemianopia caused by occipital infarctions. Clinical and computerized tomographic correlations.

Two patients with altitudinal homonymous hemianopia caused by bilateral occipital infarctions were studied. Their clinical-computerized tomographic correlations showed the anatomic representation of the superior and inferior visual fields in the lower and upper banks of the calcarine fissure, respectively. The patient with the superior-field defect was unusual because he retained normal color vision and facial recognition abilities, despite having bilateral lesions that have classically produced central achromatopsia and prosopagnosia.

Aged↗
PubMed1984

High-performance liquid chromatographic determination of metoprolol and alpha-hydroxymetoprolol concentrations in human serum, urine, and cerebrospinal fluid.

A sensitive and simplified high-performance liquid chromatographic procedure was developed for the simultaneous quantification of metoprolol and alpha-hydroxymetoprolol in human serum, as well as cerebrospinal fluid and urine. Following protein precipitation with trichloroacetic acid, the sample was alkalinized with 1 M NaOH and extracted with dichloromethane. The mobile phase consisted of acetonitrile-water (50:50) containing 0.005 M 1-heptanesulfonic acid in 0.001% acetic acid. Using pronetalol as an internal standard, compounds were quantitated using fluorescence detection at 230 nm with a 300-nm emission filter and 0.02 AUFS. Extraction recovery is approximately 80% for both compounds. The lower limits of detection are 5 ng/mL and 4 ng/mL for metoprolol and alpha-hydroxymetoprolol, respectively.

Chromatography, High Pressure Liquid↗
PubMed1980

Gray matter enhancement: a computerized tomographic sign of cerebral hypoxia.

An important computerized tomographic (CT) pattern is described, in which selective enhancement of cerebral gray matter occurs after intravenous administration of contrast medium. Analysis of 76 cases displaying the enhancement pattern revealed that the phenomenon occurs in diseases characterized by hypoxia, and may be attributed to regional vascular dysautoregulation. Eighty percent of these patients had primary cerebrovascular disease (infarctions or transient ischemic attacks); 20% with other disorders also had evidence of cerebral ischemia or infarction. When hypoxia progressed to infarction, the enhancement was accompanied by one or more parenchymal areas of decreased density. However, in transient ischemic attacks, it occurred without other parenchymal abnormality and represents the first recognized CT sign of cerebral hypoxia. Enhancement was observed within 3 weeks of onset in 80% of cases, but in 20% it persisted for up to 4 months, indicating a protracted state of dysautoregulation.

Adolescent↗
PubMed1977

Intoxication caused by interaction of chloramphenicol and phenytoin.

A patient with a brain tumor and seizures who was receiving maintenance doses of phenytoin was given chloramphenicol on three occasions. Her neurological status was both complicated and obscured by the reoccurrence of phenytoin intoxication. Retrospective drug analysis showed a marked elevation of serum concentrations of phenytoin during each course of chloramphenicol.

Chloramphenicol↗
PubMed1977

'Silent' brain metastasis from lung carcinoma determined by computerized tomography.

Computerized tomography (CT) was utilized as a preoperative screening procedure in a series of 50 patients with lung carcinoma who were neurologically asymptomatic and whose radionuclide brain scans and skull roentgenograms were normal. Three patients (6%) were discovered to have metastasis (cerebellum, occipital, corpus callosum). The metastatic lesions were only directly visualized after administration of contrast substance. The CT findings greatly influenced the therapeutic planning in these patients, and surgery was avoided in two. When feasible, patients with lung carcinoma should have CT examinations (with contrast administration) prior to thoracic surgery even if they do not have neurologic symtoms.

Adult↗
PubMed1977

Demonstration of transventricular CSF absorption by computerized tomography.

Four cases are presented of marked periventricular oedema associated with hydrocephalus on CT scan. In one of the patients oedema, as well as the hydrocephalus, subsided after successful re-establishment of CSF absorption. The most likely explanation of the periventricular oedema is increased absorption of CSF by periventricular brain tissue.

Aged↗
PubMed1976

"Normal-pressure" hydrocephalus. Relationship of clinical and radiographic findings to improvement following shunt surgery.

Analysis of 25 patients who fulfilled clinical and radiographic criteria for the diagnosis of "normal pressure" hydrocephalus (NPH) demonstrated (1) a significant relationship between presence of motor signs with good outcome and absence of motor signs with poor outcome following ventricular shunting, (2) symptoms and signs of parkinsonism in 40% of patients in whom the diagnosis of NPH was made, and (3) no reliable relationship between radiographic measurements or cisternogram appearance and outcome following shunting. The clinical picture is the most important factor in selection of NPH patients for surgery.

Adult↗
PubMed1976

Computerized axial transverse tomography in cerebrovascular disease.

One hundred eleven patients with supratentorial cerebrovascular disease were studied by computerized axial tomography (CT scanning). With one exception, every patient who had a normal scan 48 hours after the onset of symptoms was ultimately diagnosed as having had transient ischemic attack, although in nearly one-third, the clinical diagnoses at the time of the scan was infarction. A normal CT scan, therefore, augurs a good outcome of supratentorial cerebrovascular disease. Ninety-eight percent of the patients with infarction had abnormal scans, with areas of decreased density in a vascular distribution. Pitfalls in the diagnosis of infarction were (1) initially normal CT scans that changed to abnormal after 48 hours, and (2) mass effect of infarction leading to misdiagnosis of brain tumor. Serial studies eliminated both pitfalls. Intracerebral hemorrhages had a distinctive high density appearance. In 43 percent of patients whose scans showed hemorrhage, the clinical diagnosis was thrombosis. Many did not have symptoms, signs, or outcome of cerebral hemorrhage, and the diagnosis would not have been suspect were it not for the CT scan.

Adolescent↗
PubMed1976

Changes in size of normal lateral ventricles during aging determined by computerized tomography.

One hundred thirty-five normal volunteers were examined by computerized tomography (CT) and their ventricular size was measured by planimetry. A pattern of change in ventricular size from the first through the ninth decades was discerned and quantified. A gradually progressive increase in ventricular size from the first through sixth decades was followed by a dramatic increase in the eighth and ninth. The range of normal ventricular size was relatively more wide in the eighth and ninth decades than in the first seven; thus, abnormalities of ventricular size may be more easily identified in younger than older subjects. These data are more valuable than those from pneumoencephalography or autopsy studies because CT is not subject to the artifact inherent in those procedures.

Adolescent↗
PubMed1976

Autopsy correlations of computerized tomography: experience with 6,000 CT scans.

Seventy-nine autopsy correlations of CT scans showed (1) excellent correlations in normal brains, but the size of the lateral ventricles consistently larger during life than after death; (2) a distinctive pattern differentiating obstructive from nonobstructive hydrocephalus; (3) infarctions appearing as areas of decreased densities of parenchyma in vascular distributions; (4) distinctive high density appearances of hemorrhages that differentiated them from infarctions and, in general, all other pathologic processes; (5) supratentorial, intraventricular, and posterior fossa tumors appearing as masses that displaced, distorted, collapsed, and enlarged normal spaces and structures such as ventricles and pineal gland; (6) 11 false-negative CT scans in some cases of brain stem infarction, brain stem hemorrhage, and small metastasis; and (7) an overall accuracy of 86.2 percent of CT scanning in correctly identifying pathology of the brain.

Brain Diseases↗