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Biomedical subjects

R G Quisling

Publications and source records attributed to R G Quisling.

At least 37 records · Page 2Linked to original sources
PubMed1993

Alternating skew on lateral gaze. Neuroanatomic pathway and relationship to superior oblique overaction.

BACKGROUND: Previous studies of patients with heterogeneous, often diffuse neurologic disorders concluded that the neurologic substrate for alternating skew on lateral gaze may be localized at the level of the brain stem tegmentum or the cervico-medullary junction, or both. The localized nature of brain tumors offers an opportunity to further investigate the anatomic localization for this as well as other conditions. METHODS: To test the hypothesis that cervico-medullary and cerebellar lesions are responsible for alternating skew on lateral gaze, the authors investigated a series of 50 children with brain tumors, 39 of whom showed neuro-ophthalmologic abnormalities on clinical testing. Seven children had alternating skew on lateral gaze. RESULTS: All seven children with alternating skew on lateral gaze showed neoplastic involvement at the level of the cervico-medullary junction and/or the cerebellum on critical analysis of neuro-imaging studies. CONCLUSION: The authors conclude that the neuroanatomic substrate for alternating skew on lateral gaze is localized at the level of the cervico-medullary junction and/or the cerebellum. Knowing that (1) alternating skew on lateral gaze closely mimics superior oblique overaction clinically, (2) superior oblique overaction is frequently found in patients with myelomeningocele, and (3) myelomeningocele is uniformly associated with Arnold-Chiari type II which includes cerebellar and cervico-medullary region abnormalities, the authors propose that alternating skew on lateral gaze and superior oblique overaction associated with myelomeningocele have similar neuroanatomic pathways.

Adolescent↗
PubMed1993

Brainstem glioma: I. Pathology, clinical features, and therapy.

Gliomas that arise in the brain stem have been associated with a poor prognosis. Diagnostic neuroimaging readily identifies the tumor as it extends between normal brainstem structures. Histologic sampling of tumor with stereotactic methods is notoriously unreliable in establishing a definitive prognosis. Clinical trials that incorporate high-dose chemotherapy, autologous bone marrow rescue, and irradiation hold promise of better tumor control by overcoming the inaccessibility of the central nervous system to standard doses of chemotherapy. We review the pathology, clinical features, neuroimaging features, and current therapeutic concepts relative to brainstem glioma. The pediatric neurologist has a pivotal role in identifying and monitoring children with this malignancy.

Biopsy↗
PubMed1993

Brainstem and other malignant gliomas: II. Possible mechanisms of brain infiltration by tumor cells.

Gliomas that arise in the brain stem and other malignant gliomas constitute approximately 60% of all brain tumors and have eluded effective therapy, in part because they are able to infiltrate the normal brain. Histopathologic studies have confirmed the presence of infiltrating tumor cells very distant from the glioma mass. We review the neuroimaging and pathologic features of glioma-cell infiltration and some of the complex cellular and biochemical determinants of tumor-cell motility and invasiveness. Understanding how glioma cells become motile and invasive is pivotal to therapeutically targeting the machinery that enables gliomas to infiltrate the brain.

Brain Stem↗
PubMed1993

Intraventricular alpha interferon therapy for Rasmussen's syndrome.

A 4-year-old boy developed Rasmussen's syndrome and was treated with alpha interferon intraventricularly. An improvement in the epileptic and neurologic syndrome was noted for several weeks following interferon. No adverse side effects were encountered. Since hemispherectomy is the only established therapy in Rasmussen's Syndrome, further studies are needed to establish if intraventricular alpha interferon may halt the clinical progression of the syndrome.

Atrophy↗
PubMed1992

In vivo MR evaluation of Gd-DTPA conjugated to dextran in normal rabbits.

A dextran-Gd-DTPA compound has been recently synthesized utilizing 70,800 Da molecular weight dextran. This polymeric contrast agent for magnetic resonance imaging has been found chemically to be very stable and to demonstrate in vitro improved relaxivities of 1.5 to 2.3 times that of monomeric Gd-DTPA at 100 MHz. This MR experiment examines the in vivo distribution and relaxivity of the 70,800 Da molecular weight dextran-Gd-DTPA compound in a rabbit model by measuring the change in signal-to-noise ratio of a variety of organs (renal cortex, renal medulla, liver, brain, and torcula herophile) compared to the preinjection state. Results demonstrate prolonged (beyond 60 min) enhancement of the renal cortex, renal medulla, liver and torcula, and no enhancement of brain parenchyma.

Animals↗
PubMed1992

Enhancement and demyelination of the intraorbital optic nerve. Fat suppression magnetic resonance imaging.

Conventional spin-echo magnetic resonance imaging (MRI) of intraorbital optic neuritis is hampered by the adjacent high signal and chemical shift artifact of orbital fat. Frequency-selective saturation pulse MRI reduces these problems and was used to determine its utility in evaluation of intraorbital optic neuritis. Eight consecutive patients with optic neuritis underwent MRI within 1 week of the onset of visual loss. Conventional MRI with T1, proton density, and T2 weighting and frequency-selective saturation pulse MRI with T1, proton density, and T2 weighting were performed. After administration of intravenous gadopentetate dimeglumine, T1-weighted conventional and frequency-selective saturation pulse MRI were performed. Frequency-selective saturation pulse MRI showed gadopentetate dimeglumine enhancement in the intraorbital optic nerve in 7 patients and the intracranial optic nerve in 3 patients. Conventional MRI failed to show optic nerve gadopentetate dimeglumine enhancement in patients with intraorbital lesions, but did show intracranial lesions. Frequency-selective saturation pulse MRI showed bilateral optic nerve enhancement in 3 patients with unilateral visual signs and symptoms. Proton density and T2-weighted conventional MRI of the brain showed no convincing signal aberrations in the optic nerves. In the MRI evaluation of intraorbital optic neuritis: (1) frequency-selective saturation pulse fat suppression MRI is superior to T1-weighted conventional MRI in the detection of gadopentetate dimeglumine enhancement; (2) frequency-selective saturation pulse proton density and T2-weighted MRI is superior to proton density and T2-weighted conventional MRI; (3) frequency-selective saturation pulse MRI showed gadopentetate dimeglumine enhancement as well as proton density/T2-weighted signal aberration in exactly the same portion of the intraorbital optic nerve.

Adult↗
PubMed1991

Persistent nidus blood flow in cerebral arteriovenous malformation after stereotactic radiosurgery: MR imaging assessment.

Stereotactic radiosurgery has become a major force in the treatment of arteriovenous malformations (AVMs) of the brain. After treatment, obliteration of flow through the malformation occurs in 75%-85% of cases within 2 years, assuming the entire AVM nidus can be encompassed by the radiation field. Because the follow-up period is relatively long, a noninvasive means to assess residual transnidus blood flow is desirable. The authors report favorable findings after a comparative analysis of 85 posttreatment magnetic resonance images and 27 follow-up cerebral arteriograms in 34 patients treated with stereotactic radiosurgery. The authors found that transnidus flow can be determined from apparent signal intensity differences between tandem two-dimensional gradient-recalled echo images obtained first without and then with gradient moment nulling (flow compensation), with empirically derived pulse parameters. This method provides a means to monitor the reduction in AVM matrix size and to assess the extent of persistent arteriovenous shunting (ie, blood flow) across the nidus.

Brain↗
PubMed1991

Radiation-induced optic neuropathy: a magnetic resonance imaging study.

Optic neuropathy induced by radiation is an infrequent cause of delayed visual loss that may at times be difficult to differentiate from compression of the visual pathways by recurrent neoplasm. The authors describe six patients with this disorder who experienced loss of vision 6 to 36 months after neurological surgery and radiation therapy. Of the six patients in the series, two had a pituitary adenoma and one each had a metastatic melanoma, multiple myeloma, craniopharyngioma, and lymphoepithelioma. Visual acuity in the affected eyes ranged from 20/25 to no light perception. Magnetic resonance (MR) imaging showed sellar and parasellar recurrence of both pituitary adenomas, but the intrinsic lesions of the optic nerves and optic chiasm induced by radiation were enhanced after gadolinium-diethylenetriaminepenta-acetic acid (DTPA) administration and were clearly distinguishable from the suprasellar compression of tumor. Repeated MR imaging showed spontaneous resolution of gadolinium-DTPA enhancement of the optic nerve in a patient who was initially suspected of harboring recurrence of a metastatic malignant melanoma as the cause of visual loss. The authors found the presumptive diagnosis of radiation-induced optic neuropathy facilitated by MR imaging with gadolinium-DTPA. This neuro-imaging procedure may help avert exploratory surgery in some patients with recurrent neoplasm in whom the etiology of visual loss is uncertain.

Aged↗
PubMed1990

Gadolinium-DTPA-enhanced magnetic resonance imaging in optic neuropathies.

Magnetic resonance imaging (MRI), after intravenous administration of the paramagnetic agent gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA), showed enhancement of the optic nerve in 7 of 13 patients with acute optic neuritis. Four of these patients had Gd-DTPA enhancement of the intracranial optic nerve and two had involvement of the optic nerve at the orbital apex, ipsilateral to the eye with visual loss. Gadolinium-DTPA enhancement of both intracranial optic nerves was seen in one of two patients with bilateral retrobulbar neuritis. Two patients with acute radiation-induced optic neuropathy also had Gd-DTPA enhancement of the intracranial optic nerve. The authors recommend MRI with Gd-DTPA as the neuro-diagnostic procedure of choice for visualization of increased permeability of the blood-brain barrier in acute optic neuritis and radiation-induced optic neuropathy.

Adolescent↗
PubMed1988

Gianturco coil embolization of vein of Galen aneurysms: technical aspects.

Galenic A-V fistulas typically result in hydrocephalus and increased cerebral venous pressure, with symptoms of progressive seizure activity, chronic cardiac failure and failure to thrive. Surgery and arterial embolization have been only partially successful in reducing flow through these shunts. The authors present technical details of a procedure for embolizing such lesions via a transtorcular venous approach. Early results in 15 patients are reported: Twelve patients appear to have had significant symptomatic improvement; two have died of persistent heart failure, and one died of a subdural hematoma associated with ventriculostomy.

Arteriovenous Fistula↗
PubMed1986

Lead encephalopathy: symptoms of a cerebellar mass lesion and obstructive hydrocephalus.

The neurologic signs and symptoms of lead intoxication are quite varied. We review a case of lead poisoning in a 9-month-old child who presented clinically and radiographically with a posterior fossa mass effect and obstructive hydrocephalus. The predominance of edema of the cerebellum sufficient to achieve obstruction of the ventricular system represents a particularly unusual presentation of this disease process. Review of the literature for similar cases of lead encephalopathy is included.

Brain↗
PubMed1986

Small particle polyvinyl alcohol embolization of cranial lesions with minimal arteriolar-capillary barriers.

Polyvinyl alcohol foam, prepared as small particles measuring 70-150 micron when injected in intracerebral arteries of the rat, adhere to the vascular endothelium, allowing the particles to be captured without necessarily wedging intraluminally. Based on this observation, small particle microembolization was performed in a series of patients who had hypervascular cranial lesions, whose matrices angiographically appeared to have at best minimal arteriolar-capillary barriers. Each case was associated with intracranial dural sinus or cerebral venous drainage. In addition, several lesions had either venous ectasia or venous aneurysms. Symptomatic improvement occurred in all cases without apparent neurologic or pulmonary complications. These examples demonstrate the ability of very small polyvinyl alcohol foam particles to remain within the interstices of vascular lesions that display evidence of only minimal arteriolar-capillary barriers.

Adult↗
PubMed1986

Retrievable Gianturco-coil introducer.

A new delivery system for placement of Gianturco coils has been devised that permits retrieval of the coil if malposition occurs. The delivery system itself consists of a very fine coaxial cannula that will cut the monofilament once the coil is properly placed. It has been successfully used on three patients in whom a total of 48 coils were employed to occlude great vein of Galen aneurysms. The system is applicable for routine coil embolization but has particular application in treating high-flow vascular lesions (arteriovenous fistulas or malformations).

Embolization, Therapeutic↗
PubMed1986

Cavernous angioma: a review of 126 collected and 12 new clinical cases.

The histopathological, clinical, and radiological features of the intracranial cavernous angioma are reviewed, based on an analysis of 138 symptomatic, histologically verified cases. Twelve of the cases are from our own series and 126 were collected from appropriately documented reports in the modern literature. The analysis indicated that, at the time of diagnosis, one-third of the patients (49 cases) were being evaluated for seizures, one-third (40 cases) for clinical evidence of hemorrhage, and one-third (49 cases) for mass lesions. Unlike the other two groups, the group presenting with clinical evidence of hemorrhage was distinguished by a dominant age at the time of diagnosis (41% were diagnosed during the 4th decade of life), by a high incidence of prior neurological evaluation (43%), by a higher rate of diagnosis at autopsy (28%) than at operation, and by the absence of microscopic calcification within the lesion.

Adolescent↗
PubMed1986

Subcortical arteriosclerotic encephalopathy: CT spectrum and pathologic correlation.

Because of recent papers suggesting that subcortical arteriosclerotic encephalopathy (SAE) (Binswanger's disease) is more common than historically assumed, this investigation was initiated to assess the frequency of SAE, to gauge the reliability of CT in making this diagnosis, and to assess the strength of the correlation between SAE and arterial hypertension. Of 202 autopsied patients in a 17-month period, 82 had undergone antemortem CT. Of these, 20 had CT findings thought to represent varying degrees of the disease spectrum of SAE. Microscopy confirmed this diagnosis in 18 cases. The pattern of diminished attenuation in the white matter was periventricular in 16 patients (marked asymmetry in one) and limited to an isolated focus somewhat removed from the ependyma in two. Among the 16 with periventricular disease, the extent of the process by CT appeared mild in nine, moderate in five, and severe only in two. There were two false positive CT diagnoses of SAE. Among a control group of 10 patients with normal white matter by CT, seven had some microscopic evidence of SAE, although it was generally less severe than in those with positive CT scans. Subcortical arteriosclerotic encephalopathy is common and can be identified in its various forms by CT with a high degree of reliability.

Aged↗
PubMed1986

The transtorcular embolization of vein of Galen aneurysms.

Vein of Galen malformations are a diverse group of deeply located high-flow vascular lesions that are difficult to eradicate with standard surgical techniques. New nonsurgical interventional techniques offer encouraging results as alternative therapeutic choices in these complicated vascular shunts. Use of a new procedure of transtorcular embolization with Gianturco embolic coils is described in three patients harboring vein of Galen aneurysms. Two of the three patients had a satisfactory outcome. This technique is simple and quick, and can produce progressive thrombosis in these high-flow vascular fistulas.

Brain↗