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Biomedical subjects

C W Kerber

Publications and source records attributed to C W Kerber.

At least 73 records · Page 4Linked to original sources
PubMed1976

Cerebrospinal fluid hormone concentration in the evaluation of pituitary tumors.

Cerebrospinal fluid (CSF) concentrations of corticotropin, growth hormone, thyrotropin, prolactin, luteinizing hormone, and follicle stimulating hormone were measured in 28 patients with various neurologic disorders, in 49 patients with pituitary tumors of whom 22 had suprasellar extension, and in 6 patients with craniopharyngiomas. With the exception of 1 patient with pseudotumor cerebri, CSF adenohypophyseal hormone concentrations were low in patients with neurologic disease and in patients with pituitary tumor without suprasellar extension. In marked contrast, 21 to 22 patients with suprasellar extension of a pituitary tumor and 2 of 6 patients with a craniopharyngioma had elevations of one or more CSF adenohypophyseal hormones. Posttreatment CSF adenohypophyseal hormone levels fell from previously elevated levels in 4 of 5 patients. These data suggest that an elevated CSF adenohypophyseal hormone concentration is a sensitive indicator of suprasellar extension of a pituitary tumor, and posttreatment measurements are useful in determining efficacy of therapy.

Adenoma, Acidophil↗
PubMed1974

Reconstruction of objects from radiographs and the location of brain tumors.

The objective of this research is two-fold: (i) the development of a method for locating hemorrhages, blood clots, and tumors in the brain by means of ordinary hospital radiographs and without the introduction of contrast material; and (ii) the uncovering of new mathematical results through this point of view. The present note deals mainly with the first objective, but the mathematical setting and convergence and indeterminacy theorems are also described.

Absorptiometry, Photon↗
PubMedDate not supplied

Pulsatile flow artifacts in two-dimensional time-of-flight MR angiography: initial studies in elastic models of human carotid arteries.

Initial experimental and numerical analysis of artifacts due to pulsatile flow in two-dimensional time-of-flight (2D-TOF) magnetic resonance (MR) angiography are presented. The experimental studies used elastic models of the carotid artery bifurcation cast from fresh cadavers and accurately reproducing the twisting and tapering of the human blood vessels, allowing direct comparison of images with and without flow. Prominent image artifacts, including periodic ghosts and signal loss, were produced by pulsatile flow even though flow-compensated gradient waveforms were used. The dependence of artifacts due to partial saturation on pulse sequence parameters (TR and flip angle) was investigated theoretically for a simple pulsatile velocity profile and compared with experimental results from a model of a normal carotid artery. Signal reduction was observed proximal and distal to the stenosis in a model with a 70% internal carotid artery (ICA) stenosis and a model with 90% stenoses in both the ICA and the external carotid artery. Although this study deals exclusively with 2D-TOF imaging, the methods can also be applied to evaluate other MR angiography techniques.

Artifacts↗
PubMedDate not supplied

Multiplanar CT in the evaluation of degenerative spondylolisthesis. A review of 150 cases.

Degenerative spondylolisthesis (pseudospondylolisthesis) is a degenerative disorder of the intervertebral motion segment. It can be divided into two types: forward subluxation and backward subluxation. Forward subluxation is primarily a disease of the posterior joints and is found most commonly at L4/5. Retrolisthesis is a primary disorder of the disc space and is noted more commonly at L3/4. This paper reviews the CT findings in 150 patients with degenerative forward and backward subluxation. Proper evaluation of these disorders is extremely important because of the frequency of severe symptomatic spinal stenosis or foraminal encroachment.

Female↗
PubMedDate not supplied

Experimental carotid aneurysms: I. Simple surgical production and radiographic evaluation.

Using simple surgical techniques, experimental carotid aneurysms are created which simulate some types of human berry aneurysms, both in hemodynamic and radiographic behavior. End to side anastomoses of an external jugular vein graft to the common carotid artery can be carried out by radiologic personnel with no formal surgical training. Factors which cause the aneurysms to fail and fill with clot are infection, incorporation of venous valves into the aneurysm sac, poor suturing technique, and perhaps a sac too large in comparison with its neck. The models are studied and followed by percutaneous catheter angiography, and show the swirling flow seen in clinical practice. These models may be used to study and refine percutaneous catheter occlusive techniques.

Aneurysm↗
PubMedDate not supplied

Flow dynamics in a lethal anterior communicating artery aneurysm.

We describe and analyze the flow dynamics in replicas of a human anterior communicating artery aneurysm. The replicas were placed in a circuit of pulsating non-Newtonian fluid, and flows were adjusted to replicate human physiologic parameters. Individual slipstreams were opacified with isobaric dyes, and images were recorded on film and by CT/MR angiography. When flow in the afferent (internal carotid) and efferent (anterior and middle cerebral) arteries was bilaterally equal, slipstreams rarely entered the aneurysm. When flow in either the afferent or efferent vessels was not symmetrical, however, slipstreams entered the aneurysm neck, impinged upon the aneurysm dome, and swirled within the aneurysm. Unequal flow in carotid or cerebral systems may be necessary to direct pathologic, fluid slipstreams into an aneurysm.

Aneurysm, Ruptured↗
PubMedDate not supplied

Flow dynamics in the human carotid artery: I. Preliminary observations using a transparent elastic model.

PURPOSE: We developed an elastic, transparent, life-size model of the cranial vessels that allowed us to visualize carotid artery flows directly, and wish to report our observations and recorded data. MATERIALS AND METHODS: The brachiocephalic arteries of 12 adult cadavers were cannulated and infused with acrylic. The heads were dissolved in alkali and, using a "lost wax" technique, a silicone model that reflected the shape and size of the original artery was produced. These models were connected to a closed circuit of flowing fluid. The fluid was rendered opaque by injecting isobaric dyes at various points in the streams. RESULTS: These dye opacified slipstreams showed a relatively low flow area visible in the posterior and lateral aspect of the carotid bulb that acted as an internal buffer, and directed the more posterior lateral slipstreams anteriorly and at the same time increased their velocity. The cervical internal carotid artery was relatively straight and showed flow patterns that were essentially laminar. In the petrous internal carotid artery, the dye-opacified slipstreams began a helical flow pattern, and areas of flow reversal became apparent along the inner aspect (lesser curvature) of the bend. The central slipstreams tended to flow in a straighter line, passing close to, and sometimes striking the wall of, the outer portion (greater curvature) of the bend. In the cavernous internal carotid artery, helical flow continued. The central slipstreams struck the outer surface (greater curve) of the arterial bend. The point that the central slipstream struck the wall was more distal during systole than during diastole. At the supraclinoid section laminar flow again became established. Certain slipstreams selectively entered individual cranial branches. CONCLUSION: The model we describe should allow more accurate study of complicated flow dynamics in vessels supplying the brain.

Blood Flow Velocity↗
PubMedDate not supplied

Lidocaine injection into external carotid branches: provocative test to preserve cranial nerve function in therapeutic embolization.

Endovascular obliteration of hypervascular lesions of the head and neck has become clinically accepted, but it may cause stroke and peripheral cranial nerve palsy. By using a flow-controlled technique to deliver the materials and by knowing the vascular anatomy of the cranial nerves, these problems are less likely to occur. Occasionally, though, vascular anatomy is distorted by the lesion or is anomalous in its distribution. A provocative test of lidocaine injected into the appropriate artery seems to offer a functional test of whether the capillary bed will tolerate small-particle or liquid plastic occlusion. Twenty-six patients had various branches of their external carotid arteries challenged with lidocaine. Three developed transient palsies, and their treatments were modified. None of the 26 patients developed a complication of embolization.

Aged↗
PubMedDate not supplied

Polyvinyl alcohol foam-Gelfoam for therapeutic embolization: a synergistic mixture.

Gelfoam and polyvinyl alcohol foam particles each have advantages and disadvantages for therapeutic embolization. It was theorized and confirmed that a mixture of the two retains the advantages and eliminates the disadvantages of each. Two mixtures were prepared, tested in animals, and used successfully in 14 patients. It was found that the mixtures of Gelfoam and polyvinyl alcohol foam particles fulfilled the expectations and needs for particulate embolic materials.

Adrenal Gland Neoplasms↗
PubMedDate not supplied

Iotrol, a new myelographic agent: 1. Radiography, CT, CSF clearance, and brain penetration.

Four new myelographic agents, metrizamide, iopamidol, iohexol, and iotrol, were studied in the subarachnoid space of cynomolgus monkeys. Plain films and computed tomographic scans documented the transport of each material throughout the space and into the brain. At the concentration used (300 mg I/ml), all gave good radiopacity for myelography and delineation of the cerebral subarachnoid space. All four cleared similarly from the ventricular system. Metrizamide, however, penetrated the brain in greater degree and persisted longer than the other three agents. Next in persistence was iopamidol and least, and both statistically equal, iotrol and iohexol.

Animals↗