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Biomedical subjects

R E Latchaw

Publications and source records attributed to R E Latchaw.

At least 37 records · Page 2Linked to original sources
PubMed1994

"Brain attack": the rationale for treating stroke as a medical emergency.

Stroke is the third leading cause of death in the United States, behind only heart disease and cancer. With an estimated three million survivors of stroke in the United States, the cost to society, both directly in health care and indirectly in lost income, is staggering. Despite recent advances in basic and clinical neurosciences, which have the potential to improve the treatment of acute stroke, the general approach to the acute stroke patient remains one of therapeutic nihilism. Most basic science studies show that to be effective, acute intervention to reperfuse ischemic tissue must take place within the first several hours, as is the case with ischemic myocardium. In addition, most neuroprotective agents must also be administered within a short time frame to be effective at salvaging at-risk tissue. Recent studies have suggested that the outcome after intracerebral and subarachnoid hemorrhage is improved with early intervention. However, most stroke patients fail to present to medical attention within this short "window of opportunity." The public's knowledge about stroke is woefully inadequate. However, clinicians who deal with stroke can use the dramatic changes in the treatment of acute myocardial infarction over the last 2 decades as a guide for shaping changes in the management of acute stroke. Comprehensive educational efforts aimed at clinicians and the public at large have dramatically reduced the time from symptom onset to presentation and treatment for acute myocardial infarction, enabling treatment methods such as thrombolysis to be effective. The Decade of the Brain offers a unique opportunity to all concerned with the treatment of the patient with acute stroke to engage in a concerted effort to bring patients with a "brain attack" to specialized neurological attention within the same timeframe that the "heart attack" patient is handled. Such an effort is justified because, although at the present time there are few therapeutic interventions of "proven" value in the treatment of acute stroke, there is more than sufficient suggestive evidence that a number of approaches may be beneficial within the first few hours after the onset of the stroke.

Brain↗
PubMed1994

Adrenoleukodystrophy: a scoring method for brain MR observations.

PURPOSE: To develop a scoring method for brain observations in patients with X-linked adrenoleukodystrophy. METHODS: One hundred seventy-five brain MR scans in 83 male subjects less than 20 years of age with proved biochemical defects were reviewed. A severity score (0 to 34), based on a point system derived from location and extent of disease and the presence of focal and/or global atrophy, was calculated for each exam. RESULTS: Fifty-five of the 83 patients showed MR findings consistent with adrenoleukodystrophy. Two major patterns were observed. A posterior pattern (mean score, 9; range, 0.5 to 25) was present in 80% of patients, and an anterior pattern (mean score, 10; range, 2 to 18) was present in 15% of patients. Serial MR imaging, positive for adrenoleukodystrophy in 34 patients (mean follow-up, 23 months; range, 2 months to 6 years 11 months), showed progressive disease in 52%, progressive disease with subsequent stabilization in 18%, stable disease in 24%, and minimal improvement in 6%. CONCLUSION: The adrenoleukodystrophy MR severity scoring method is a measure that can be used with standard MR images. When used in conjunction with clinical parameters, this scoring method may help define better the natural history of adrenoleukodystrophy and monitor response to developing therapies.

Adolescent↗
PubMed1994

Childhood cerebral form of adrenoleukodystrophy: short-term effect of bone marrow transplantation on brain MR observations.

PURPOSE: To report the serial brain MR observations in patients with childhood-onset cerebral adrenoleukodystrophy 1 to 2 years after bone marrow transplantation. METHODS: Eight boys with childhood-onset cerebral adrenoleukodystrophy have undergone successful transplantation at our institution. Seven patients (mean age, 8 years 10 months; range, 5 years 3 months to 11 years 9 months) had serial MR studies before and after transplantation. An MR severity score (0 to 34) based on disease location and the presence or absence of focal atrophy was calculated for each patient scan. RESULTS: Posttransplantation serial MR showed improvement in two patients, stabilization in three patients, and worsening of MR signal changes in two patients. The patient with the most striking progression had systemic graft-versus-host disease. Although the adrenoleukodystrophy MR severity score did not change in three patients after transplantation, two of these patients did show improved margination of disease. CONCLUSION: Bone marrow transplantation can affect brain MR observations in childhood-onset cerebral adrenoleukodystrophy. Although brain MR findings do not typically resolve, they do seem to stabilize, which is an improvement over the natural MR history of the disease.

Adrenoleukodystrophy↗
PubMed1994

Steady-state free precession imaging of the inner ear.

The authors describe a steady-state free precession technique for imaging the inner ear. Although the signal-to-noise ratio is not as great as with other three-dimensional MR techniques, the inherent high contrast of inner ear structures makes this a valuable technique for patients with sensorineural hearing loss and for those who refuse paramagnetic contrast material.

Contrast Media↗
PubMed1994

Radiologic diagnosis and staging of head and neck squamous cell carcinoma.

The predominant extracranial head and neck cancer in adults is squamous cell carcinoma. The purpose of this article is to discuss the radiographic evaluation of these patients with computed tomography (CT) or magnetic resonance (MR) imaging prior to therapeutic intervention. Specific focus is given to the efficacy of CT and MR imaging, as an adjunct to clinical staging, for evaluation of the primary tumor, and metastatic adenopathy. MR imaging, because of its improved soft tissue contrast and multiplanar capability, is probably superior to CT for evaluation of the primary tumor in patients with squamous cell carcinoma. CT, however, remains the gold standard for identifying metastatic adenopathy and in most institutions remains the study of choice for evaluating this patient population.

Carcinoma, Squamous Cell↗
PubMed1994

Radiologic diagnosis, staging, and follow-up of adult central nervous system primary malignant glioma.

Glioma represents the most common primary intra-axial brain tumor. Currently, magnetic resonance (MR) imaging is the study of choice for the radiographic evaluation of patients with primary central nervous system glioma prior to and following therapeutic intervention. Computed tomography and MR imaging are frequently used for stereotactic biopsy and mapping. MR spectroscopy and/or thallium-201 single photon emission computed tomography may prove helpful in differentiating recurrent malignancy from radiation-induced necrosis.

Adolescent↗
PubMed1993

Long-term outcome of Hurler syndrome following bone marrow transplantation.

Previous reports suggested a therapeutic response of lysosomal storage diseases such as Hurler syndrome following bone marrow transplantation. However, a clearer understanding of outcome has awaited long-term follow-up. We evaluated prospectively 11 consecutive patients with Hurler syndrome receiving marrow from an HLA-identical sib donor between September 1983-October 1988. Follow-up evaluations included assessment of donor engraftment by restriction fragment polymorphism analysis, determination of leukocyte alpha-L-iduronidase level, measurement of lumbar cerebrospinal fluid (CSF) pressure, computerized tomography (CT) of the brain, and psychometric testing. In this series there was a survival rate of 9/11 (82%) with all survivors showing complete (7 patients) or partial (2 patients) donor engraftment. Prospective longitudinal evaluation of the 9 surviving children, now 3.8-8.9 years posttransplantation (median 5.5) demonstrated persistence of previously deficient leukocyte alpha-L-iduronidase at levels reflecting the donor genotype and degree of donor engraftment. Urinary glycosaminoglycan excretion declined to near-normal within 5 months of donor engraftment. Prior to treatment, 7 of 8 children studied were found to have occult intracranial hypertension (lumbar CSF pressure > 20 cm CSF); however, all surviving children attained normal or near-normal pressure within 18 months of donor engraftment. Longterm follow-up CT imaging of the brain did not show progressive volume loss (cerebral atrophy) after donor engraftment. Of 9 survivors, 4 children having a developmental quotient (DQ, Mental Development Index on Bayley Scales of Infant Development) above 80 prior to transplantation subsequently maintained IQ scores above this level. However, 5 patients with lower pretransplant DQ scores now have significant cognitive deficits and attention deficit hyperactivity disorder. Progressive brain damage resulting from communicating hydrocephalus may be prevented by successful engraftment. Early transplantation of children with Hurler syndrome who have normal intelligence is likely to have the clearest benefit because long-term intellectual outcome will be limited by brain damage which has occurred prior to treatment.

Bone Marrow Transplantation↗
PubMed1993

The use of nonionic contrast agents in neuroangiography. A review of the literature and recommendations for clinical use.

RATIONALE AND OBJECTIVES: Several large studies have demonstrated the improved safety record of nonionic versus ionic contrast agents for intravenous administration. However, nonionic agents are much more expensive than ionic agents. The author addresses whether, given this large cost differential, nonionic contrast agents should always be used in neuroangiography (cerebral and spinal cord angiography and intravascular neurointerventional procedures). The answer could come from a closer examination of the effects of contrast agents on the brain. METHODS: There have been a number of animal experiments and clinical trials performed using a variety of available intravascular contrast agents. In an attempt to arrive at some reasonable conclusions regarding the use of contrast agents today, the author reviews several of these studies. In the human studies, three areas were analyzed: 1) cerebral angiography, 2) spinal cord angiography, and 3) intravascular neurointervention. The author explains why demonstrating the effect of a contrast agent on the brain or spinal cord in the clinical setting is more difficult than studying the effect of this agent on the liver, heart, or kidney. For example, obtaining objective measurements of altered cerebral physiology following intravascular injection of a contrast agent may itself alter the physiology. In lieu of objective measurements, investigators must rely on apparent changes in behavior, mentation, or the production of a focal neurologic deficit. However, it is extremely difficult, if not impossible, to separate the effect of the contrast agent from the effects of the arteriographic procedure, or from the disease process being evaluated. RESULTS: The neuronal environment is protected by the blood-brain barrier. A number of animal experiments have demonstrated that nonionic agents produce breakage of the blood-brain barrier less frequently than do ionic agents. In these studies, nonionic agents also produced fewer neurologic effects than did ionic agents. The human studies showed no statistically significant differences in neurologic effects when ionic and nonionic agents were compared. Cerebral: minor changes in heart rate were more common with ionic than with nonionic agents; there were no significant electroencephalogram changes in any of the patients studied. Spinal cord: the effects of intravascular injections of contrast material into the spinal cord of experimental animals have been rarely evaluated; direct comparisons of contrast agents in human spinal cord angiography have not been performed. Neurointervention: there have been no comparative studies of different contrast agents used during intravascular neurointerventional procedures in humans. CONCLUSIONS: Extensive animal data demonstrate that nonionic contrast agents are safer than ionic for cerebral angiography. Animals in the cited studies show less blood-brain barrier disruption, fewer direct neuronal effects, and fewer neurobehavioral deficits. However, the overwhelming conclusion from the human studies is that, while there is evidence in the experimental animal that nonionic agents produce fewer neurologic effects than do ionic agents, no study to date has been able to translate these findings into an apparent clinical difference in humans, mainly because it's so difficult to detect and measure neurologic changes in human trials. In addition, differences in neurologic effects between contrast agents used in human studies may be relatively small. Thus, one must make an educated guess as to the appropriate use of contrast agents in the context of their apparent clinical safety and cost-benefit ratio.

Angiography↗
PubMed1993

Diagnostic imaging of the brain stem.

The small size of the brain stem, its location between the petrous pyramids, and the density of neuroanatomic structures in its substance make imaging of the brain stem one of the most challenging aspects of diagnostic neuroradiology. The relative value of CT, MRI, and angiography in the diagnosis of various brain stem lesions is reviewed. The contributions that can be made by more advanced diagnostic and functional imaging techniques are presented.

Brain Diseases↗
PubMed1992

Quantitative computer tomography in Alzheimer's disease: a re-evaluation.

This investigation addresses the question of usefulness of computer-tomographic (CT) scanning in discriminating patients with Alzheimer's disease (AD) from healthy, aged controls. Quantitative measures of brain volume loss found to be significant by other investigators as well as additional unique variables are used to discriminate 58 longitudinally studied patients meeting NINCDS-ADRDA criteria for the clinical diagnosis of probable AD from 59 controls. The sensitivity and specificity of both single CT scan parameters and multivariate models comprised of such CT parameters are explored. Reasons for diagnostic misclassification are also illuminated.

Aged↗
PubMed1992

Imaging of intracranial infection.

Modern imaging techniques define the anatomic region infected and the evolution of the disease, help to evaluate treatment efficacy, and frequently can help to determine extra-central nervous system sources of infection, such as sinusitis or mastoiditis. These techniques are discussed by anatomic region, and differential diagnosis based on image pattern is formulated. Special attention is given to the findings in the immunocompromised host and in congenital infection.

Acquired Immunodeficiency Syndrome↗
PubMed1989

MR imaging of the pars interarticularis.

MR imaging of the lumbar spine has become a useful method for the noninvasive evaluation of low back pain. However, bone abnormalities are more difficult to detect than soft-tissue lesions, such as herniated disk. We reviewed 14 MR images of the lumbar spine in adults with spondylolisthesis. These were correlated with CT scans and plain films in all cases. From the CT scans and plain films we found that seven patients had spondylolysis and that seven had other causes for their spondylolisthesis. It was our opinion that the MR images suggested an abnormality of the pars interarticularis in all seven of the cases confirmed to have spondylolysis and in six of the seven patients that did not have spondylolysis. We also studied four cadaver lumbar spine, obtained as blocks of tissue, and scanned in the coronal, sagittal, and axial planes with MR and in the sagittal and axial planes with CT. The tissue blocks were then sectioned in the sagittal plane. Spondylolysis is suggested on sagittal MR images when there is an inability to resolve the marrow signal in the pars as uninterrupted from the superior to the inferior facet. This is caused by a dark signal on all pulsing sequences in the pars resulting from marginal sclerosis at the site of the break. If there is also a gap at the site of the break then there will also be an increased signal in the gap resulting from the presence of soft tissue. We found four situations in which the pars can simulate spondylolysis on sagittal MR images: (1) sclerosis of the neck of the pars: (2) partial volume imaging of the degenerative spur of the superior facet slightly lateral to the pars; (3) partial facetectomy; and (4) osteoblastic metastatic replacement of the marrow of the pars.

Adult↗
PubMed1989

The acetazolamide challenge: imaging techniques designed to evaluate cerebral blood flow reserve.

Cerebral blood flow was analyzed by the stable xenon (Xe)/CT scanning technique in 29 patients with significant vascular lesions before and after administration of an acetazolamide (Diamox) vasodilatory challenge. Three response types were identified: I, normal flow before Diamox with flow augmentation after Diamox; II, low flow before Diamox with flow augmentation after Diamox; and III, low or normal flow before Diamox with no augmentation or decreased flow after Diamox. Twenty-four percent of the patients studied qualified for category III. We believe that patients in this category represent a group of individuals without blood flow reserve whose clinical management should include careful consideration of their hemodynamic status. The Xe/CT scanning technique with the addition of Diamox flow challenge is a clinically accessible and effective method for assessing cerebral blood flow and blood flow reserve.

Acetazolamide↗
PubMed1988

Local "inverse steal" induced by hyperventilation in head injury.

Hyperventilation is used routinely to reduce intracranial pressure in victims of severe head injury. In the clinical setting, the effects of hyperventilation on regional cerebral blood flow usually are not known. We describe a case in which hyperventilation resulted in local, paradoxic increases in cerebral blood flow (i.e., "inverse steal") associated with a reduction in intracranial pressure. Although the reduced intracranial pressure was thought to be beneficial, serial computed tomographic scans suggested that the inverse steal response could have promoted cerebral edema, resulting in secondary brain injury.

Brain Injuries↗
PubMed1988

Comparison of MR imaging, CT, and angiography in the evaluation of the enlarged cavernous sinus.

Twenty-one patients with enlargement of the cavernous sinus were studied with CT and MR imaging. Eighteen of the patients also had cerebral angiography. MR was superior to CT in differentiating parasellar aneurysms from neoplastic masses. MR was also superior to both CT and angiography in defining the relationships of cavernous sinus neoplasms to the internal carotid artery, pituitary gland, optic chiasm, infundibulum, and fifth cranial nerves. Only in the definition of bone erosion or hyperostosis was MR inferior to another method (CT). We conclude that MR should be the initial diagnostic study in patients with symptoms of a parasellar mass, with supplementation when necessary by CT and angiography.

Adult↗