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Biomedical subjects

L D Cromwell

Publications and source records attributed to L D Cromwell.

At least 19 recordsLinked to original sources
PubMed1992

Three-dimensional computerized tomography angiography in the diagnosis of cerebrovascular disease.

Computer-generated three-dimensional reconstruction of the intracranial vascular system obtained by contrast-enhanced computerized tomography (CT) has been used in the diagnosis of 20 patients with known or suspected intracranial cerebrovascular disease. This technique allows visualization of the intracranial vasculature without exposing patients to the risks associated with intra-arterial angiography. The color prints and videotape images generated have been used to diagnose the presence of intracranial aneurysms, arteriovenous malformations, and venous angiomas. They have also been used to rule out structural abnormalities in patients with suspected intracranial vascular pathology and to screen patients with a strong family history of intracranial aneurysm. In 11 patients who underwent both three-dimensional CT angiography and intra-arterial angiography, the diagnostic correlation was 100%. No complications from the procedures or from incorrect diagnosis have been encountered. Although this technique requires further development and clinical evaluation, the authors' early experience with three-dimensional CT angiography suggests that this may become a valuable tool in the diagnosis of patients with cerebrovascular disease.

Adolescent↗
PubMed1991

Filtering noise from images with wavelet transforms.

A new method of filtering MR images is presented that uses wavelet transforms instead of Fourier transforms. The new filtering method does not reduce the sharpness of edges. However, the new method does eliminate any small structures that are similar in size to the noise eliminated. There are many possible extensions of the filter.

Artifacts↗
PubMed1988

Magnetic resonance imaging in the diagnosis and treatment of Lhermitte-Duclos disease (dysplastic gangliocytoma of the cerebellum).

Lhermitte-Duclos disease is a rare disorder characterized by a slowly enlarging mass lesion in the cerebellum. The pathophysiology of the disease is poorly understood, but recent reports have suggested that a clinically significant mass may recur many years after total gross removal of the tumor. Computed tomography and angiography have been relatively insensitive in imaging the tumor either at presentation or during the postoperative period. The authors present three patients with histologically proven Lhermitte-Duclos disease who have undergone magnetic resonance imaging (MRI). In the first case, preoperative T1- and T2-weighted images clearly demonstrated the location and extent of the lesion, which was verified at operation. In the other two cases, only postoperative images were obtained. These demonstrated the extent of residual tumor and indicate a high probability of lesion expansion during periods of 4 and 10 years, respectively. We conclude that MRI is an important tool in both the diagnosis and the treatment of patients with Lhermitte-Duclos disease.

Adult↗
PubMed1987

The utility of MR in planning the radiation therapy of oligodendroglioma.

Newer methods of radiation therapy for treating oligodendroglioma after surgical resection have produced promising results using high doses of radiation. However, these doses are close to those that cause necrosis of normal brain, making the accurate spatial localization of tissue at risk for containing tumor cells more important. Because MR imaging is superior to CT in detecting some types of intracranial disease, nine patients with oligodendroglioma were studied with both MR and CT. Results were compared with surgical findings. In six cases, MR identified some tumor volume found during surgery that was not detected by CT. In addition, the interface between abnormality (tumor plus edema) and normality was depicted much more clearly by MR than by CT in most cases. Such superior depiction of the margins of abnormality is important for radiation therapy planning because of the known tendency of oligodendroglioma to infiltrate adjacent edema, making all areas of abnormality potential tumor-bearing tissue. Finally, MR showed normal brain tissue in areas considered suspicious by CT, because they were not well seen on CT in several patients. In these cases of low-grade oligodendroglioma, MR was believed to be superior to CT in providing information needed for radiation therapy planning because of its ability to distinguish tumor and adjacent edema (considered tissue at risk for containing microscopic tumor) from contiguous normal brain.

Adult↗
PubMed1986

Magnetic resonance imaging in cerebrotendinous xanthomatosis.

In a patient with cerebrotendinous xanthomatosis, magnetic resonance imaging (MRI) revealed findings of demyelination in the cerebral white matter, which was also hypodense on CT. The MRI abnormality seemed to be clinically significant in this patient with progressive dementia and abnormal gait.

Atrophy↗
PubMed1986

Histologic analysis of tissue response to bucrylate-pantopaque mixture.

A toxicologic-pathologic study of isobutyl-2-cyanoacrylate (Bucrylate) was carried out first in dogs and then in humans whose arteriovenous malformations were infused with this embolic agent. The canine specimens obtained at 7, 18, 28, and 147 days after embolization showed the development of a mild histiocytic giant cell reaction, which evolved to end-state sclerotic arteritis. The response was confined to the vessels and did not involve contiguous parenchymal tissues. Ten human specimens, obtained from 1 hr to 7 years after treatment, showed a similar bland reaction with no evidence of suppuration or premalignant changes.

Adolescent↗
PubMed1985

MR imaging in radiation therapy planning. Work in progress.

Magnetic resonance (MR) imaging may provide information about tumor location, extent, and margins unavailable from other imaging modalities. The impact of MR on radiation therapy planning was investigated in this study. Thirty patients about to undergo radiation therapy underwent routine radiography and computed tomography (CT) to define the extent of their disease. A radiation therapy plan, including portal placement and size, was drawn up based on this information alone. The patients also underwent MR studies. After the original therapy plan was created, the MR study results were made available to the radiation therapist. In 53% (16/30) of the cases, MR information led to a measurable change in the therapy plan; in an additional 33% (10/30), MR information increased confidence in the original plan. MR may become a necessary procedure for radiation therapy planning in many cases.

Humans↗
PubMed1985

Experimental carotid aneurysms: Part 2. Endovascular treatment with cyanoacrylate.

Using our modification of the vein patch technique, we created 16 aneurysms in the common carotid arteries of dogs. After a stabilizing and healing period, these aneurysms were treated using percutaneous catheter techniques. Coaxial microcatheters were placed into the aneurysms, and a mixture of isobutyl 2-cyanoacrylate and tantalum dust was infused through the microcatheter using real time fluoroscopic control. Fifteen of the 16 aneurysms were successfully occluded; 1 was a failure because of total occlusion of the carotid artery. One human facial artery aneurysm was similarly treated. The ease and technical details of the treatment are discussed. Although the results are encouraging, we believe that it would be prudent to broaden the animal experimentation rather than to begin human use. Because no experimental aneurysm models are yet physiological, our results must be applied with caution to human intracranial aneurysms.

Adolescent↗
PubMed1979

Cyanoacrylate occlusion of carotid-cavernous fistula with preservation of carotid artery flow.

We report a new treatment for carotid-cavernous fistula. Using a flow-guided, balloon-tipped microcatheter, we catheterize the fistula itself, verify balloon entry into the fistula with fluoroscopy and x-ray films, and then infuse the tissue adhesive isobutyl-2-cyanoacrylate with careful fluoroscopic control. Three patients have had their fistulas occluded, with preservation of flow through the internal carotid artery. This balloon microcatheter allows the radiologist to perform a reversible test occlusion. All three patients had neurological changes during or after the procedure, and in one we inadvertently occluded several distal middle cerebral artery branches without permanent neurological deficit. No patient became blind or developed 3rd, 4th, or 6th nerve palsy from the treatment. This technique seems to have promise as another method for the obliteration of carotid-cavernous fistula.

Arteriovenous Fistula↗
PubMed1979

Calibrated leak balloon microcatheter: a device for arterial exploration and occlusive therapy.

In quest of an endarterial treatment for intracranial arteriovenous malformations and fistulas, a microcatheter which can be flow-guided into third- and fourth-order branches of the intracranial arteries was developed. This permits controlled deposition of a vascular occlusive polymer (isobutyl-2 cyanoacrylate). Goals and experimental techniques are reviewed and clinical experience on the first 25 patients is presented. Complications included one stroke and three catheters glued in place, but refinements in technique have permitted avoidance of complications over the 14 months before this report.

Animals↗
PubMed1979

Computed tomography of intracerebral leukemic masses.

Five patients with differing types of leukemia had clinical symptoms of a localized intracerebral leukemic mass. Computed tomography (CT) demonstrated a mass of equal or increased density relative to normal brain; a zone of surrounding edema was variable. In each case, the mass showed evidence of relatively uniform contrast enhancement. CT appearance of leukemic masses is consistent and quite different from the findings in other central nervous system complications of leukemia and its aggressive treatment.

Acute Disease↗
PubMed1979

Modification of cyanoacrylate for therapeutic embolization: preliminary experience.

Cyanoacrylate is a satisfactory material for therapeutic embolization, but it has the disadvantage of not being radiopaque and polymerizing within 1 sec after contact with ionic materials. Its behavior was modified with varying concentrations of iophendylate and were able to satisfactorily control its polymerization from 1 to 30 sec. This control should allow penetration of arteriovenous malformations, which is necessary if cure is to result. The iophendylate adds radiopacity and seems to enhance the suspension of tentalum, another opacifying agent. Preliminary experience in dogs is encouraging, but too few humans have been treated with this method to recommend it as more than an experimental procedure at this time.

Bucrylate↗
PubMed1978

Intraarterial cyanoacrylate: an adjunct in the treatment of spinal/paraspinal arteriovenous malformations.

Arteriovenous malformations are difficult lesions to treat whether surgical or catheter occlusive therapy is used. If the major feeders are ligated or blocked, other arteries open quickly to supply the malformation. Isobutyl 2-cyanoacrylate, deposited with a calibrated leak balloon microcatheter, has given satisfactory short term improvement in both the signs and symptoms of two patients with spinal arteriovenous malformations. Superselective placement of the catheter system, a provocative test perfusion of the arteriovenous malformation and its supplying vessels before the acutal occlusion, and high quality fluoroscopy and angiographic equipment added to the safety of the procedure. No long term results are available, but this system may prove itself another tool in the catheter therapist's armamentarium.

Adult↗
PubMed1978

Cerebral ischemia. I. Current angiographic techniques, complications, and safety.

The angiographic evaluation of the transient ischemic attack has been technically difficult, time consuming, and complication prone because of underlying arteriosclerosis and other medical diseases. The examination described depends upon small soft catheters, dynamic fluoroscopy for positioning, and selective magnified views of the arteries needed for surgical planning. Five basic views are exposed. On the side of clinical interest, a lateral view of the head and neck, a frontal view of the head, and a fluoroscopically positioned view of the carotid bifurcation are obtained; on the other side the frontal view is omitted. A total of 662 consecutive studies were performed on 603 patients without death or permanent strokes. The only permanent complication was a partial radial nerve palsy.

Cerebral Angiography↗
PubMed1978

Remote effects of neuroblastoma.

Neuroblastoma, which is primarily an extracranial disease, has remote manifestations which can be confusing. Neurologic signs and symptoms such as opsoclonus (dancing eyes), ataxia, blindness, and cord paralysis may precede by several months the manifestations of the primary tumor in a distant site such as the abdomen. Descriptions of nine cases demonstrate the various modes of presentation and some of the unusual aspects of this disease. The recent advent of computed tomography requires a reevaluation of the neuroradiologic approach to the evaluation of neuroblastoma.

Bone Neoplasms↗