Biomedical subjects

G S Forbes

Publications and source records attributed to G S Forbes.

At least 37 records · Page 2Linked to original sources

PubMed1987

Central nervous system toxicity after liver transplantation. The role of cyclosporine and cholesterol.

We describe severe central nervous system (CNS) toxicity, manifested by confusion, cortical blindness, quadriplegia, seizures, and coma, associated with cyclosporine treatment in three patients undergoing liver transplantation. CT and magnetic resonance studies disclosed a severe, diffuse disorder of the white matter. All side effects and radiographic findings were reversed with discontinuation or a reduction in the dose of cyclosporine. We also observed an inverse association between CNS side effects and total serum cholesterol levels after transplantation. A retrospective analysis of 54 liver transplantations performed in 48 patients revealed that 13 patients had symptoms of CNS toxicity associated with the use of cyclosporine. These patients' total serum cholesterol levels in the first week after transplantation were reduced as compared with those in patients without symptoms (mean +/- SE, 94 +/- 4 mg per deciliter vs. 132 +/- 6, or 2.44 +/- 0.10 mmol per liter vs. 3.43 +/- 0.16). We conclude that cyclosporine therapy for immunosuppression in liver transplantation may cause a syndrome of encephalopathy, seizures, and white-matter changes and that this is most likely to occur in patients with low total serum cholesterol levels after transplantation.

Blindness↗

PubMed1987

Familial cavernous malformations of the central nervous system and retina.

We studied a family in which 4 persons from three generations had multiple cavernous malformations ("angiomas") of the central nervous system (CNS) and/or retina and found accounts in the literature of sixteen other families with this condition. In these families with familial cavernous malformation of the CNS and retina, 92% of pathologically documented vascular malformations were cavernous; 50% of those subjects affected had multiple CNS and/or retinal vascular malformations and 68% (excluding probands) were symptomatic. Cutaneous vascular lesions were an inconsistant manifestation. Autosomal dominant inheritance with high penetrance was confirmed.

Adolescent↗

PubMed1986

Correlation of radiological features to failure of lumbar intervertebral disc chemonucleolysis.

Chemonucleolysis was performed in 103 patients for lumbar disc prolapse. Multiple (two) interspaces were injected in only seven patients. Radiographically, all patients had myelographic or computerized tomography evidence of disc prolapse. Eighty-seven of 100 patients who were available for follow-up review had improved. Ten of 13 patients with persistent symptoms required a laminectomy. Altered spinal alignment was evident in five of the 13 patients with persistent symptoms: retrolisthesis in three and myelographic disc defect on the convex aspect of the scoliosis in two. Review of radiographic studies was carried out in an attempt to establish guidelines for patient selection so as to decrease the rate of failure in chymopapain treatment.

Adolescent↗

PubMed1985

Magnetic resonance imaging in a routine clinical setting.

The results of magnetic resonance imaging (MRI) examinations in the first 1,000 consecutive patients who were studied by this technique at our institution were reviewed to determine the disease states encountered, the sensitivity and accuracy of results, and the value of the examination as compared with computed tomography and other imaging procedures. The MRI device was a 0.15-tesla resistive magnet that used a variety of saturation recovery, spin echo, and inversion recovery pulse sequences to produce images. MRI was found equal to or superior to other imaging techniques in most cases. Exceptions included organs or body regions that are prone to excessive respiratory or vascular motion, lesions that necessitate exquisite spatial resolution for diagnosis, and lesions in which angulation of the viewing plane is necessary for optimal depiction. Fresh blood and calcification within a lesion were also difficult to detect with use of MRI.

Adolescent↗

PubMed1985

Intracranial hypertension in Behçet's disease: demonstration of sinus occlusion with use of digital subtraction angiography.

We describe two patients with Behçet's disease who had symptomatic intracranial hypertension due to cerebral venous sinus thrombosis. The sinus thrombosis was demonstrated by digital subtraction angiography. In those patients with Behçet's disease who have unexplained headaches, papilledema, and elevated cerebrospinal fluid pressure, venous digital subtraction angiography is an expedient, accurate, and safe procedure for demonstrating intracranial venous thrombosis.

Adolescent↗

PubMed1985

Orbital volume measurements in enophthalmos using three-dimensional CT imaging.

The purpose of this study was to investigate enophthalmos by measuring the volume of various orbital structures using off-line computer techniques on images generated by a CT scanner. Eleven patients with enophthalmos had CT scans of the orbits consisting of 30 to 40 adjacent 1.5-mm slices. The data from the scans were analyzed on a Nova 830 stand-alone computer system using software programs that allowed measurement of total bony orbital volume, total soft-tissue volume, globe volume, orbital fat volume, neuromuscular tissue volume, and apex-to-globe distance in the horizontal plane. These data were analyzed comparing the volumes in the normal eye with the volumes in the enophthalmic eye in each patient. The analysis demonstrated a statistically significant increase in bony orbital volume in the enophthalmic eye, but the total soft-tissue volume, fat volume, neuromuscular tissue volume, and globe volume were the same as in the normal eye. The apex-to-globe distance, a measure of the degree of enophthalmos, was less in the enophthalmic eye than in the normal eye. These results suggest that in the majority of patients, the cause of posttraumatic enophthalmos is increased bony orbital volume rather than by soft-tissue loss or fat necrosis. (Several patients showed no volume discrepancies, and it is likely that cicatricial contracture is responsible for the enophthalmos in these cases.) This study suggests that the objective of surgery for correction of enophthalmos in patients with a volume discrepancy should be to decrease the volume of the bony orbit and to increase the anterior projection of the globe.

Adipose Tissue↗

PubMed1983

Adrenoleukodystrophy (ALD): clinical and CT features of a childhood variant.

A variant of childhood adrenoleukodystrophy (ALD) affected two male cousins. The characteristic features include a progressive frontal lobe syndrome, frontal pole CT hypodensity, abnormal levels of plasma very-long-chain fatty acids, and a family history consistent with X-linked inheritance.

Adrenoleukodystrophy↗

PubMed1983

Radiographic assessment of squamous cell carcinoma of the temporal bone.

Squamous cell carcinoma of the temporal bone usually presents with tumor and edema occluding the external auditory canal. Accurate evaluation of the extent of such a tumor is therefore difficult. Assessment of these tumors and subsequent surgical management depends primarily on the preoperative radiographic findings. This paper discusses the evolution of the radiographic assessment of carcinomas of the ear canal. Certain cases have been selected to demonstrate the advantages and disadvantages of the radiographic studies in use. Mastoid x-ray views and petrous tomograms have been the standard methods of studying these lesions. Their interpretation, however, often exaggerates or underestimates the true extent of these carcinomas. Early and later generation computed tomography (CT) scans offered improvement in determining tumor involvement but still did not give the needed detail for surgical planning. High-resolution CT scanning of the petrous bones now offers the surgeon excellent views of these tumors. This paper places special emphasis on this technique and also discusses indications for operability.

Adult↗

PubMed1983

The accuracy and limitations of intravenous digital subtraction angiography in the evaluation of atherosclerotic cerebrovascular disease: angiographic and surgical correlation.

Intravenous digital subtraction angiography (IV-DSA) and subsequent conventional selective carotid angiographic examinations were reviewed in 78 patients who were suspected of having cerebrovascular disease, and the results were correlated with surgical findings in 53 patients. The impact of the information provided by each of these examinations on subsequent therapy was reviewed. IV-DSA examinations of acceptable quality accurately depict atherosclerotic lesions in the cervical carotid arteries. We found IV-DSA to be deficient for detection of intracranial vascular disease.

Angiography↗

PubMed1982

Ophthalmodynamometry and ocular pneumoplethysmography for detection of carotid occlusive disease.

The accuracy of ophthalmodynamometry and ocular pneumoplethysmography for predicting pressure-significant lesions of the internal carotid system was compared in a series of 119 consecutive patients (210 arteries) having cerebral angiography. Overall accuracy (92.5%) for ocular pneumoplethysmography was significantly better than that for ophthalmodynamometry (76%). The difference was most apparent in predicting abnormality (85% for ocular pneumoplethysmography and 49% for ophthalmodynamometry), particularly for bilateral lesions (80% for ocular pneumoplethysmography and 37% for ophthalmodynamometry). There were few false-positive results with either test.

Arterial Occlusive Diseases↗

PubMed1982

Computed tomography of orbital tumors, including late-generation scanning techniques.

The role of computed tomography (CT) in the detection and diagnosis of orbital tumors at the Mayo Clinic is reviewed. Special techniques of late-generation scanners, including multiplane reformatted imaging, off-axis projections, high-resolution retrospective analysis, and thin-section scanning, have been evaluated in various ways for their clinical application in 42 recent cases. The overall series involved 133 proved orbital tumors. The detection rate and information obtained established CT as the method of choice for diagnosis of tumors of the orbit.

Adolescent↗

PubMed1982

High-resolution dynamic ultrasound imaging of the carotid bifurcation: a prospective evaluation.

One hundren patients underwent high-resolution dynamic ultrasound imaging of the carotid bifurcation immediately before cerebral angiography. The examinations were interpreted independently. A positive ultrasound interpretation indicated the presence of moderate to extensive atheromatous plaque, while a negative interpretation indicated normal vessels or minimal atheromatous disease. Ten percent of the ultrasound examinations were technically unsatisfactory. Of the remaining studies, there was satisfactory correlation between ultrasound and angiography in approximately 85% and disagreement in 15%. The majority of ultrasound errors were "false positive" (although these probably represent false-negative angiograms). Although atheromatous disease was accurately detected by ultrasound, stenosis, ulceration, intraluminal thrombus, and vessel occlusion were not reliably identified.

Adolescent↗

PubMed1982

Digital angiography: introducing digital techniques to clinical cerebral angiography practice.

Digital subtraction angiography provides a computerized radiographic method of imaging the vascular system. These computer techniques may be used with arterial catheterization (digital arterial angiography) and with intravenous contrast injection (digital venous angiography). Both methods are changing the diagnostic evaluation and therapeutic follow-up of patients with cerebrovascular disease.

Brachiocephalic Trunk↗

PubMed1981

Computerized tomography and adrenoleukomyeloneuropathy.

Five cases of adrenoleukomyeloneuropathy illustrate the differential computerized tomographic (CT) appearance of the disease subtypes adrenoleukodystrophy (ALD) and adrenomyeloneuropathy (AMN). In ALD, the CT is distinctive, reflecting predominant involvement of cerebral white matter. The CT in AMN may be nonspecifically abnormal since the spinal and peripheral white matter are mainly affected. Recognition of an obscure neurologic disease as a leukodystrophy may aid the clinician in designing appropriate biochemical testing and in categorizing the disease process.

Addison Disease↗

PubMed1981

Angiographic findings in herpes zoster arteritis.

Four adults patients who experienced an ipsilateral hemispheric deficit 6 to 8 weeks after having developed herpes zoster ophthalmicus were seen during a six-month period. All four patients underwent full-circle angiography, including study of the extracranial arteries in the three older patients. Each examination demonstrated areas of segmental constriction of arteries on the ipsilateral side; two locations that were especially affected were the A2 segment of the pericallosal artery beneath the genu of the corpus callosum and the M4 segment of the middle cerebral artery. The cerebral arteries of the opposite hemisphere and the extracranial vessels did not contain demonstrable abnormalities. Pathological studies suggest that patients with this syndrome may have a necrotizing arteritis of ipsilateral blood vessels; in patients with disseminated zoster, a granulomatous angiitis of cerebral blood vessels has been found. We propose that the pattern of angiographic abnormalities described here is characteristic of herpes zoster arteritis; furthermore, the distribution pattern of the lesions suggests that the virus may spread to these arteries via branches of the ophthalmic division of the trigeminal nerve.

Adult↗

PubMed1981

Intracranial granulocytic sarcoma complicating childhood acute myelomonocytic leukemia.

A 15-year-old girl with acute myelomonocytic leukemia in bone marrow remission presented with signs and symptoms of an intracranial mass lesion. A computed tomographic scan revealed a large cystic lesion in the left posterior parietal lobe, which biopsy proved to be a granulocytic sarcoma. She responded well to a combined treatment program utilizing surgical excision, radiation therapy, and intrathecal chemotherapy. Four previously reported cases are reviewed, and our findings suggest that increasing numbers of such cases may become evident as primary therapy prolongs remission duration in children with acute nonlymphocytic leukemia.

Adolescent↗

PubMed1981

Pineal tumors in children and adolescents. Treatment by CSF shunting and radiotherapy.

Tumors of the pineal region account for 3% to 8% of pediatric intracranial tumors. The treatment of such tumors has been in a state of flux between conservative therapy (cerebrospinal fluid shunting and radiotherapy) and direct surgical removal. A brief history and review of the literature with analysis of both approaches is given, and the Mayo Clinic's experience with conservative treatment of tumors in the pineal region in patients 20 years old and younger (27 cases) is studied and analyzed. The series comprises 21 boys and six girls, with an age range of 1 to 20 years (mean 13.7 years). Follow-up examinations are complete and range from 1 to 24 years, with a mean follow-up period of 7.8 years. The median survival time for these patients treated with shunt and radiotherapy is 17.7 years. There was no mortality from treatment and complications were rare. The details of the clinical presentation, diagnostic findings, pathology, therapy, recurrence, and survival are presented. All patients under 6 years of age (six cases) had recurrences, 50% in other areas in the brain and 50% in the spinal cord, perhaps pointing to the need for whole-brain and spinal-axis irradiation in patients in this age group. The results of this study of the conservative approach form a standard against which results of any other type of therapy may be compared.

Adolescent↗

PubMed1980

Orbital tumors evaluated by computed tomography.

Computed tomography (CT) of more than 90 orbital tumors revealed both benign and malignant neoplasms, including hemangiomas, lacrimal gland tumors, lymphomas, carcinomas, metastases, pseudotumors, and optic nerve tumors. Detection of orbital tumors was better and the information gained more complete with CT than with any other modality.

Adolescent↗