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Biomedical subjects

R E Latchaw

Publications and source records attributed to R E Latchaw.

At least 109 records · Page 6Linked to original sources
PubMed1976

Intra- and extracerebral arachnoid cyst. An atypical roentgenographic presentation.

Arachnoid cysts present in a variety of ways, and the preoperative diagnosis usually requires a high degree of suspicion. Bony changes consistent with a chronic focal mass effect, a relative paucity of clinical findings compared to the size of the lesion, and an extracerebral mass with an intracerebral component suggest the possibility. We present a case in which there appears to be a large, deep intracerebral mass associated with an extracerebral expansion.

Adult↗
PubMedDate not supplied

Lumbar myelography with iohexol and metrizamide. A comparative multicenter prospective study.

Diagnostic quality and adverse reactions associated with metrizamide and iohexol as contrast agents for lumbar myelography were compared in a prospective randomized double-blind study in 350 patients at seven centers. Both contrast media were administered in comparable volumes at a concentration of 180 mg I/ml. Overall quality of radiographic visualization was graded as "good" or "excellent" in 95% of 175 metrizamide studies and in 98% of 175 iohexol myelograms. Ninety-three patients examined with metrizamide (53%) and 130 patients studied with iohexol (74%) experienced no discomfort during or after myelography. The incidence of postmyelographic headache was 38% with metrizamide and 21% with iohexol. Nausea and vomiting were also more common with metrizamide. Five patients examined with metrizamide (3%) experienced transient confusion and disorientation after lumbar myelography. No such reactions were observed after iohexol myelography.

Adult↗
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Meningeal sarcoma mimicking an acute subdural hematoma on CT.

A case of meningeal sarcoma arising at the site of a prior subdural hematoma and mimicking an acute subdural hematoma on noncontrast CT is presented. The potential confusion between a hyperdense, nonhemorrhagic lesion and a hematoma on CT is highlighted. This report also reviews the possible relationship between meningeal injury and subsequent neoplastic change.

Acute Disease↗
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Progress in cerebrovascular disease: local cerebral blood flow by xenon enhanced CT.

A noninvasive technique for measuring local cerebral blood flow (LCBF) by xenon enhanced x-ray transmission computed tomography (CT) has been developed an reported quite extensively in recent years. In this method, nonradioactive xenon gas in inhaled and the temporal changes in radiographic enhancement produced by the inhalation are measured by sequential computed tomography. Time dependent xenon concentrations within various tissue segments in the brain are used to derive both local partition coefficient (lambda) and LCBF. An assessment of this method reveals that although it provides functional mapping of blood flow with excellent anatomic specificity, there are distinct limitations. The assumptions underlying this methodology are examined and problems associated with various potential applications of this technique are discussed.

Animals↗
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Clinical experience with the use of xenon-enhanced CT blood flow mapping in cerebral vascular disease.

Cerebral blood flow mapping with the xenon-enhanced/CT method has become a useful clinical tool in the management of patients with occlusive cerebral vascular disease. Studies involving 4-5 minutes of inhaling a xenon/oxygen mixture (less than or equal to 35%) can now be performed routinely with acceptable patient tolerance and compliance. Four cases with acute and chronic ischemic injuries are reported here to illustrate the manner in which this method has been used to characterize flow pattern in such patients and the relevance of this flow information to clinical patient management.

Adult↗
PubMedDate not supplied

[Non-invasive evaluation of extracranial and intracranial vascular disease].

INTRODUCTION: Over the last 10 years the diagnosis of chronic and acute cerebrovascular disorders has been greatly improved. We have available now not only better anatomical imaging methods that allow a more precise localization and subtyping of the problem, but also physiological methods that look at the function and interaction between the brain's parenchyma and its perfusion. DEVELOPMENT: In this article the utility and clinical indications of ultrasonography (duplex and Transcranial Doppler) including the modern techniques of embolus detection are described. Also discussed are Magnetic resonance angiography, perfusion-diffusion magnetic resonance, computed tomographic angiography (angio-CT), single photon emission tomography (SPECT). Clinical examples of real cases exemplify the use of these techniques.

Brain↗
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Xe/CT cerebral blood flow evaluation of delayed symptomatic cerebral ischemia after subarachnoid hemorrhage.

PURPOSE: We examined the xenon/CT method of measuring cerebral blood flow in assessing the location, pattern of onset, and severity of delayed cerebral ischemia. PATIENTS AND METHODS: Fourteen patients with delayed neurologic deficits due to ischemia were selected from a group of 66 patients with subarachnoid hemorrhage. All blood flow studies were performed within 12 hours of deterioration and at regular intervals during medical management. RESULTS: In 10 of the 14 patients, noncontrast CT did not identify a cause for deterioration, whereas the blood flow study revealed diminished flow values. Location of blood flow reduction was variable. In five of the 14 patients, blood flow reduction was closely related anatomically to the vessel of aneurysm origin. In another three, blood flow reduction was anatomically remote to the vessel of origin. The remaining six experienced local and remote cerebral blood flow reduction. Six of 14 patients suffered sudden, devastating deterioration, refractory to therapy and associated with blood flow of 15 cc/100 g.min or less, resulting in local or widespread infarction. The remaining eight had less severe blood flow reduction and did not infarct those territories. CONCLUSIONS: Vasospasm can affect remote vessels as severely as local vessels and can affect remote vessels alone. Diminished cerebral blood flow correlated closely with clinical vasospasm in this group of patients. Xenon/CT cerebral blood flow studies can identify tissue at risk of infarction when CT is normal.

Adult↗
PubMedDate not supplied

Anatomy of the brainstem: correlation of in vitro MR images with histologic sections.

MR imaging was performed on three formaldehyde-fixed brainstem specimens that were sectioned in the axial plane and myelin stained. The histologic sections were used to identify and label the structures demonstrated on short TR/TE axial MR images. Fiber tracts and nuclei that cannot be resolved on in vivo scans were well delineated by in vitro MR. Improved gray-white differentiation may be due to much greater T1 shortening of gray matter relative to white matter after fixation. The excellent anatomic detail provided by these scans should facilitate comparison of clinical scans with histologic sections.

Brain Stem↗
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Embolization of intramedullary arteriovenous malformations of the spinal cord.

Intramedullary spinal cord arteriovenous malformation (AVM) can be a devastating disease. It is not usually amenable to surgery without producing severe neurologic deficit. Previously, the risk of cord ischemia was considered a contraindication to therapeutic embolization. Three patients with intramedullary spinal cord AVMs were examined and treated using polyvinyl alcohol foam, mixed with Gelfoam in two cases. In all three cases there was marked improvement, in two to complete normalcy and in the other to near-normalcy. Successful therapy involves the appropriate angiographic mapping, choice of embolus size and composition, and challenge of function by either test occlusion or long perfusion with contrast material.

Adult↗
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Neuroradiologic aspects of pediatric orthotopic liver transplantation.

To investigate the occurrence of neurologic symptomatology in pediatric orthotopic liver transplantation patients and to evaluate the utility of CT in uncovering the origin of their symptoms, we reviewed the medical records and head scans (when performed) of 71 patients. Neurologic problems occurred in 48%; the majority involved seizures, mental status changes, or coma. Patients who only had seizures generally had negative CT scans, except for two patients with minimal subarachnoid hemorrhages. Three-quarters of the comatose patients, however, had significant intracerebral hemorrhages defined by CT. Prominent sulci and ventricles were found in approximately one-third of the patients scanned, but did not correlate with symptomatology or steroid dose.

Cerebral Hemorrhage↗
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Balloon test occlusion of the internal carotid artery with stable xenon/CT cerebral blood flow imaging.

We describe a technique to predict preoperatively the safety of permanently occluding an internal carotid artery. The method was performed by imaging stable xenon cerebral blood flow (CBF) with the internal carotid artery both open and temporarily occluded with a nondetachable balloon on a double lumen Swan-Ganz catheter. Patients were those in whom we planned to sacrifice the internal carotid artery (those with giant or inaccessible aneurysms) or those in whom such a sacrifice was at least likely (those with skull base tumors). Patients were divided into three groups on the basis of a comparison of occluded and nonoccluded CBF values. Group-I patients had no significant change in CBF with internal carotid artery occlusion; group-II patients showed a symmetric decrease in CBF; and group-III patients had an asymmetric decrease in CBF, always greater on the occluded side. A fourth group clinically failed to tolerate even brief carotid occlusion. The internal carotid artery in one patients from group III was sacrificed at surgery: the size and shape of his postoperative infarct corresponded almost exactly to the area of asymmetrically decreased CBF on his occluded study. The data suggest that if surgery is likely to result in permanent occlusion of the internal carotid artery, then patients who are at risk for delayed neurologic injury due to a compromised cerebral blood flow should have arterial bypass grafts before such surgery is performed.

Brain Ischemia↗
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Reformatted imaging to define the intercommissural line for CT-guided stereotaxic functional neurosurgery.

Functional stereotaxic neurosurgery has traditionally required definition of the line between the anterior and posterior commissures as the basis for defining the target site for a procedure such as stereotaxic thalamotomy. While axial computed tomographic (CT) imaging precisely defines the third ventricle and the commissures, the planes of the axial images are not necessarily parallel to the important intercommissural line. A technique is described in which coronal oblique reformations are obtained, with the reformations passing through both the anterior and posterior commissures. Stereotaxic coordinates of the target obtained from this reformatted image are directly transferable to the CT-compatible Leksell frame. Both imaging and surgery are performed on the scanner, which is located in an operating room especially designed for CT-guided surgical procedures.

Brain↗
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Iohexol for cervical myelography via C1-C2 puncture: study of efficacy and adverse reactions.

Cervical myelography with iohexol via C1-C2 puncture was performed in 30 patients in two medical centers using a concentration of 240 mg l/ml. The study demonstrated iohexol to be a safe contrast medium without significant changes in neurologic and physical examination, vital signs, electrocardiogram, or hematologic or blood chemistry parameters. Fifteen patients had electroencephalograms (EEGs); two were abnormal. In one patient the baseline EEG demonstrated nonspecific slow waves in the temporal regions bilaterally that remained unchanged after myelography. In the second patient, transient changes in the left hemisphere during either hyperventilation or photic stimulation on postmyelographic EEG had not been present on the baseline recording. The relation of these changes to the drug remains unclear. Iohexol was found to be an efficacious myelographic contrast agent, with good to excellent myelograms in 93% of cases. Headache occurred in 13% and nausea in 3%.

Adult↗