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Biomedical subjects

Stephen S Gebarski

Publications and source records attributed to Stephen S Gebarski.

At least 19 recordsLinked to original sources
PubMed2007

Patterns of cognitive change over time and relationship to age following successful treatment of Cushing's disease.

Chronically elevated levels of cortisol have been associated with changes in cognitive functioning and brain morphology. Using Cushing's disease as a model to assess the effects of high levels of cortisol on cognitive functioning, 27 patients with Cushing's disease were examined at baseline and three successive follow-up periods up to 18 months after successful surgical treatment. At all follow-up periods, patients were administered cognitive tests as well as measures of plasma and urinary free cortisol. Structural MRIs and a depression measure were taken at baseline and one-year follow-up. Results showed that there is a specific pattern of significant cognitive and morphological improvement following successful treatment. Verbal fluency and recall showed recovery, although brief attention did not. Age of participants was a significant factor as to when recovery of function occurred; younger patients regained and sustained their improvement in cognitive functioning more quickly than older participants. Improvement in verbal recall also was associated with a decrease in cortisol levels as well as an increase in hippocampal formation volume one year after treatment. Overall, these findings suggest that at least some of the deleterious effects of prolonged hypercortisolemia on cognitive functioning are potentially reversible, up to at least 18 months post treatment.

Adolescent↗
PubMed2006

Improvement in mood and ideation associated with increase in right caudate volume.

BACKGROUND: The basal ganglia, particularly caudate, are hypothesized to play a role in affective and obsessive-compulsive disorders. The depressive syndrome is a feature of untreated Cushing's disease. The objective of this study was to test the hypothesis that after treatment of Cushing's disease reduces elevated cortisol, improvement in mood and related ideations are associated with increase in caudate volume. METHODS: In this longitudinal, interventional study of 23 patients with Cushing's disease, 24-hour urinary free cortisol, structural magnetic resonance imaging and behavioral measures were obtained prior to treatment and approximately one year after pituitary microadenomectomy. Five SCL-90-R subscales measuring change in mood, related ideations and physical symptoms were utilized. RESULTS: Partial correlations (adjusted for age and time since surgery) showed change in caudate, but not hippocampal, volume was significantly associated with change in behavioral SCL-90-R subscales, indicating selectivity for structure. Right but not left caudate showed associations, suggesting selectivity for lateralization. Right caudate volume increase was significantly associated with decreases in Depression, Anxiety, Obsessive-Compulsive, and Paranoid scores, but not with Somatization (physical symptoms), indicating specificity for behavioral but not physical variables. LIMITATIONS: A limitation is that relatively low-resolution scans were utilized. Although most likely not diminishing the significant findings, less sensitive methodology could lead to an increased probability of a type 2 error. CONCLUSIONS: These findings support the concept that caudate, and likely right caudate, participates in human brain circuitry regulating mood.

Adenoma↗
PubMed2006

Nontuberculous mycobacterial infection of a metastatic brain neoplasm in an immunocompromised patient.

BACKGROUND: Nontuberculous mycobacterial infections occur in immunocompromised patients but so rarely involve the central nervous system (CNS) that they may not be included in a differential diagnosis of CNS lesions in such patients. OBJECTIVE: To illustrate a putative mechanism for nontuberculous mycobacterial infection of the CNS via breakdown of the blood-brain barrier by metastatic neoplasm. RESULTS: A 56-year-old man who had undergone renal transplantation in February 2003 and was taking an immunosuppressive regimen of mycophenolate mofetil and cyclosporine was seen in the emergency department after a syncopal episode. Head computed tomography revealed a single focal occipital lesion with vasogenic edema. Hospital admission and further workup led to diagnosis of metastatic carcinoma infected with nontuberculous mycobacteria in the setting of a disseminated nontuberculous mycobacterial infection. CONCLUSION: This case illustrates that breakdown of the blood-brain barrier by metastatic neoplasm may provide a route of access for a pathogen that is not normally seen in the CNS.

Adenocarcinoma↗
PubMed2006

Multiple brain infarcts and Balint syndrome in aortic arch angiosarcoma.

A 50-year-old woman presented with subacute cognitive decline, impaired eye movements, and simultanagnosia, components of the Balint syndrome. She had relatively low blood pressure in the left arm and left finger clubbing. Brain imaging identified multiple acute infarcts. Transesophageal echocardiography showed no cardiac abnormalities but demonstrated a thickened aortic wall and an intraluminal aortic arch mass. The surgical specimen revealed angiosarcoma. Of the few reported angiosarcomas involving the aorta, most have been located in the abdominal segment. This is only the second reported case of aortic arch sarcoma presenting with stroke.

Agnosia↗
PubMed2006

Papilledema in the assessment of ventriculomegaly.

To determine whether ventriculomegaly is associated with ongoing increased intracranial pressure (ICP), physicians often rely on corroborative imaging features such as altered periependymal signal, distortion of ventricular shape, subarachnoid space flattening, and an increase in ventricular size over time. In 2 patients with new headache and altered mental status, symptoms and ventriculomegaly were dismissed as long-standing and not reflective of current ICP elevation. In the first patient, ICP was considered normal because there were no corroborative imaging features of elevated ICP. In the second patient, ICP was considered normal because ventricular size was stable over a 1-year period. The diagnosis of ICP elevation was finally made by ICP monitoring after papilledema was recognized. Ventriculoperitoneal shunting rapidly resolved the papilledema and markedly improved mentation. Brain imaging may often be an unreliable guide to the presence of elevated ICP. In such patients, the finding of papilledema is a critical determinant of management.

Adult↗
PubMed2005

Evaluation of the functional diffusion map as an early biomarker of time-to-progression and overall survival in high-grade glioma.

Diffuse malignant gliomas, the most common type of brain tumor, carry a dire prognosis and are poorly responsive to initial treatment. The response to treatment is typically evaluated by measurements obtained from radiographic images several months after the start of treatment; therefore, an early biomarker of tumor response would be useful for making early treatment decisions and for prognostic information. Thirty-four patients with malignant glioma were examined by diffusion MRI before treatment and 3 weeks later. These images were coregistered, and differences in tumor-water diffusion values were calculated as functional diffusion maps (fDM), which were correlated with the radiographic response, time-to-progression (TTP), and overall survival (OS). Changes in fDM at 3 weeks were closely associated with the radiographic response at 10 weeks. The percentage of the tumor undergoing a significant change in the diffusion of water (V(T)) was different between patients with progressive disease (PD) vs. stable disease (SD) (P < 0.001). Patients classified as PD by fDM analysis at 3 weeks were found to have a shorter TTP compared with SD (median TTP, 4.3 vs. 7.3 months; P < 0.04). By using fDM, early patient stratification also was correlated with shorter OS in the PD group compared with SD patients (median survival, 8.0 vs. 18.2 months; P < 0.01). On the basis of fDM, tumor assessment provided an early biomarker for response, TTP, and OS in patients with malignant glioma. Further evaluation of this technique is warranted to determine whether it may be useful in the individualization of treatment or evaluation of the response in clinical protocols.

Adult↗
PubMed2005

Functional diffusion map: a noninvasive MRI biomarker for early stratification of clinical brain tumor response.

Assessment of radiation and chemotherapy efficacy for brain cancer patients is traditionally accomplished by measuring changes in tumor size several months after therapy has been administered. The ability to use noninvasive imaging during the early stages of fractionated therapy to determine whether a particular treatment will be effective would provide an opportunity to optimize individual patient management and avoid unnecessary systemic toxicity, expense, and treatment delays. We investigated whether changes in the Brownian motion of water within tumor tissue as quantified by using diffusion MRI could be used as a biomarker for early prediction of treatment response in brain cancer patients. Twenty brain tumor patients were examined by standard and diffusion MRI before initiation of treatment. Additional images were acquired 3 weeks after initiation of chemo- and/or radiotherapy. Images were coregistered to pretreatment scans, and changes in tumor water diffusion values were calculated and displayed as a functional diffusion map (fDM) for correlation with clinical response. Of the 20 patients imaged during the course of therapy, 6 were classified as having a partial response, 6 as stable disease, and 8 as progressive disease. The fDMs were found to predict patient response at 3 weeks from the start of treatment, revealing that early changes in tumor diffusion values could be used as a prognostic indicator of subsequent volumetric tumor response. Overall, fDM analysis provided an early biomarker for predicting treatment response in brain tumor patients.

Adolescent↗
PubMed2004

Metastatic neuroblastoma presenting with binocular blindness from intracranial compression of the optic nerves.

A 2-year-old boy with blindness as an isolated symptom was found to have no light perception binocularly because of compression of both optic nerves by a neuroblastoma infiltrating the walls of the optic canals and medial sphenoid bone. Imaging disclosed a primary tumor near the kidney and multiple osseous metastases. Although neuroblastoma commonly causes blindness by metastasis to the orbit, it rarely causes bilateral blindness from intracranial compression of the optic nerves. This is the first report of bilateral blindness as the presenting feature.

Blindness↗
PubMed2004

Pentobarbital vs chloral hydrate for sedation of children undergoing MRI: efficacy and recovery characteristics.

BACKGROUND: Chloral hydrate (CH) sedation for magnetic resonance imaging (MRI) is associated with significant failure rates, adverse events and delayed recovery. Pentobarbital (PB), reportedly produces successful sedation in 98% of children undergoing diagnostic imaging. This study compared the efficacy, adverse events and recovery characteristics of CH vs PB in children undergoing MRI. METHODS: With Institutional Review Board approval and written consent, children were randomly assigned to receive intravenous (i.v.) PB (maximum 5 mg x kg(-1) in incremental doses) or oral CH (75 mg x kg(-1)) prior to MRI. Sedation was augmented with 0.05 mg x kg(-1) doses of i.v. midazolam (maximum 0.1 mg x kg(-1)) as necessary. Adverse effects, including hypoxaemia, failed sedation, paradoxical reactions and behavioural changes, the return of baseline activity, and parental satisfaction were documented. The quality of MRI scans was evaluated by a radiologist blinded to the sedation technique. RESULTS: PB facilitated an earlier onset of sedation (P = 0.001), higher sedation scores (P = 0.01), and less need for supplemental midazolam compared with CH. Severe hypoxaemia occurred in two children (6%) in the PB group. Fourteen per cent of the PB group experienced a paradoxical reaction, 9% sedation failure and 11% major motion artefact, compared with 0% (P = 0.05), 3 and 2% (P = NS), respectively, in the CH group. CH and PB were both associated with a high incidence of motor imbalance, and agitation. However, children who received PB had a slower return to baseline activity (P = 0.04). CONCLUSIONS: Although PB facilitated a quicker sedation onset and reduced the requirement for supplemental sedation, it produced a higher incidence of paradoxical reaction and prolonged recovery with a similar failure rate compared with CH.

Administration, Oral↗
PubMed2003

Improvement in learning associated with increase in hippocampal formation volume.

BACKGROUND: Patients with spontaneous Cushing's syndrome are exposed to elevated levels of endogenous cortisol for months to years. We previously reported that hippocampal formation volume (HFV) increased in such patients after treatment lowered cortisol to normal concentrations. In the present study, we examined whether the structural increase was associated with improvement in cognition. METHODS: Twenty-four patients with Cushing's disease were studied before treatment and following treatment. Magnetic resonance imaging was used to measure HFV and caudate head volume. Neuropsychologic tests of verbal cognition, learning, and memory were also administered. RESULTS: Patients showed variability in improvement on neuropsychologic test performance. After partialing out age, education, duration of illness, and time since surgical treatment, greater improvement in word list learning, as measured by the Selective Reminding Test was associated with greater increase in HFV (r =.59, p <.02). There were no significant associations between improvement in paragraph or paired-word learning or memory tasks and increase in HFV. Improvement in other verbal tasks not strongly dependent on the hippocampus were not significantly associated with increase in HFV. CONCLUSIONS: After cortisol levels decline to normal concentrations, structural volumetric increase in HFV is accompanied by functional improvement in learning of unrelated words.

Adenoma↗
PubMed2003

Cerebellitis in an adult with abnormal magnetic resonance imaging findings prior to the onset of ataxia.

BACKGROUND: Brain magnetic resonance imaging (MRI) findings during acute cerebellar ataxia in cases of postinfectious cerebellitis are frequently normal. This has resulted in the use of other imaging modalities, such as single-photon emission computed tomography, to aid diagnosis. OBJECTIVE: To illustrate the chronologic occurrence of cerebellar ataxia, abnormal findings on MRI, and cerebral spinal fluid pleocytosis in an adult case of postinfectious cerebellitis. METHODS: Case report. RESULTS: A patient with a 6-week history of occipital headaches and only mild tandem gait difficulty had abnormal MRI findings that were consistent with cerebellar inflammation. As cerebellar ataxia progressed in parallel with cerebral spinal fluid pleocytosis, MRI findings indicative of cerebellar inflammation resolved, while single-photon emission computed tomography showed cerebellar hyperperfusion. Recovery of neurologic function was accompanied by clearing of the pleocytosis and residual MRI-detected cerebellar atrophy. CONCLUSION: This case demonstrates that transient abnormalities can be detected by MRI before clinical manifestations of cerebellitis appear, while hyperperfusion detected by single-photon emission computed tomography is prolonged.

Adult↗
PubMed2003

Linear magnetic resonance enhancement and optic neuropathy in primary angiitis of the central nervous system.

A 38-year-old woman developed incoherent mentation, tremor, ataxia, and bilateral optic disc edema with mildly depressed visual acuity, nerve fiber bundle defects, and a left afferent pupillary defect. Magnetic resonance imaging of the brain disclosed striking linear contrast enhancement radiating from the ventricular borders. Lumbar puncture showed a normal opening pressure with a lymphocytic pleocytosis and elevated protein. On the basis of these findings, the initial diagnosis was viral or post-viral meningoencephalitis and the patient was not treated. During the next 4 weeks, her condition worsened. A brain and meningeal biopsy disclosed findings typical of primary angiitis of the central nervous system. With aggressive treatment, her neurologic status and magnetic resonance imaging normalized and her optic neuropathy improved markedly. Optic neuropathy and linear magnetic resonance imaging enhancement should be recognized as features of primary angiitis of the central nervous system.

Adult↗
PubMed2003

Characterization of a stapes ankylosis family with a NOG mutation.

OBJECTIVE: To characterize the otologic phenotype in a family with autosomal dominant stapes ankylosis, hyperopia, and skeletal abnormalities caused by a mutation in the noggin gene (NOG). STUDY DESIGN: Case series. SETTING: Academic tertiary care center. PATIENTS: Eight affected and 3 unaffected family members. MAIN OUTCOME MEASURES: History, physical and radiologic examination, and surgical outcomes. RESULTS: Although affected members were initially presumed to have typical nonsyndromic otosclerosis, the clinical data were most consistent with an autosomal dominant congenital stapes ankylosis syndrome. Eight of eight affected family members had bilateral low-frequency conductive hearing loss. Six of eight underwent fenestration procedures and/or stapedectomies. All members with initial postoperative closure of the air-bone gap returned to their baseline conductive loss within 2 years. Two affected family members had documented maximal conductive hearing loss by age 4, and two members without previous otologic surgery have not experienced sensorineural hearing loss. High-resolution temporal bone computed tomography showed stapes ankylosis and indistinction of the incudomalleal junction bilaterally and bony regrowth over the stapedotomy for those with stapedectomies. Detailed physical and radiologic examination identified multiple other skeletal abnormalities. CONCLUSIONS: Although this phenotype may present as classic otosclerosis to the otolaryngologist, detailed investigation revealed a congenital stapes ankylosis syndrome. Because is essential in regulating normal bone development and maturation, mutations in this gene may be associated with excessive bony overgrowth and refixation of the stapes footplate after initial successful surgery. Patients with hereditary conductive hearing loss should be assessed to rule out subtle features of a skeletal syndrome.

Ankylosis↗
PubMed2003

Evaluation of cancer therapy using diffusion magnetic resonance imaging.

Assessment of the effectiveness of cancer therapy traditionally relies on comparison of tumor images acquired before and after therapeutic intervention by inspection of gross anatomical images to evaluate changes in tumor size. The potential for imaging to provide additional insights related to the therapeutic impact would be enhanced if a specific parameter or combination of parameters could be identified that reflect tissue changes at the cellular or physiological level. This information could also provide a more sensitive and earlier indicator of treatment response in an individual animal or patient. Diffusion magnetic resonance imaging can detect relatively small changes in tissue structure at the cellular level and thus provides an opportunity to quantitatively and serially follow therapeutic-induced changes in solid tumors. This article provides an overview of the use of diffusion magnetic resonance imaging as a surrogate marker for quantitating treatment responsiveness in both preclinical and clinical studies.

Animals↗
PubMed2002

Survival and failure patterns of high-grade gliomas after three-dimensional conformal radiotherapy.

PURPOSE: The goal of three-dimensional (3-D) conformal radiation is to increase the dose delivered to tumor while minimizing dose to surrounding normal brain. Previously it has been shown that even escalated doses of 70 to 80 Gy have failure patterns that are predominantly local. This article describes the failure patterns and survival seen with high-grade gliomas given 90 Gy using a 3-D conformal intensity-modulated radiation technique. PATIENTS AND METHODS: From April 1996 to April 1999, 34 patients with supratentorial high-grade gliomas were treated to 90 Gy. For those that recurred, failure patterns were defined in terms of percentage of recurrent tumor located within the high-dose region. Recurrences with more than 95% of their volume within the high-dose region were considered central; those with 80% to 95%, 20% to 80%, and less than 20% were considered in-field, marginal, and distant, respectively. RESULTS: The median age was 55 years, and median follow-up was 11.7 months. At time of analysis, 23 (67.6%) of 34 patients had developed radiographic evidence of recurrence. The patterns of failure were 18 (78%) of 23 central, three (13%) of 23 in-field, two (9%) of 23 marginal, and zero (0%) of 23 distant. The median survival was 11.7 months, with 1-year survival of 47.1% and 2-year survival of 12.9%. No significant treatment toxicities were observed. CONCLUSION: Despite dose escalation to 90 Gy, the predominant failure pattern in high-grade gliomas remains local. This suggests that close margins used in highly conformal treatments do not increase the risk of marginal or distant recurrences. Our results indicate that intensification of local radiotherapy with dose escalation is feasible and deserves further evaluation for high-grade gliomas.

Female↗
PubMed2002

Hemifacial spasm caused by vertebral artery dolichoectasia.

PURPOSE: To display the characteristic magnetic resonance imaging (MRI) abnormalities associated with hemifacial spasm caused by compression of the seventh cranial nerve by a dolichoectatic vertebral artery. DESIGN: Interventional case report. METHODS: Correlation of imaging and clinical findings. RESULTS: In a 36-year-old man with mild left hemifacial spasm, MRI showed an enlarged (dolichoectatic) vertebral artery that compressed the seventh cranial nerve at its exit from the caudal pons. Manifestations of hemifacial spasm were relieved with periocular botulinum toxin injections. CONCLUSION: In hemifacial spasm, MRI may show compression of the ipsilateral seventh cranial nerve or other structural abnormalities. Relief of hemifacial spasm may occur with botulinum toxin injection or with neurosurgical intervention designed to relieve the compression.

Adult↗
PubMed2002

Delayed visual loss following pergolide treatment of a prolactinoma.

A patient who had achieved marked improvement in vision and shrinkage of a prolactinoma following treatment with pergolide (0.1 mg/day) suffered a marked worsening of vision 7 months after continued treatment at the same dose. Brain magnetic resonance imaging (MRI) at the time of visual loss showed further shrinkage of the tumor and prolapse of the chiasm into the pituitary fossa. The dose of pergolide was cut in half (0.05 mg/day); 12 months later, vision had completely recovered. Brain MRI at the time of visual recovery showed no change in the position of the prolapsed chiasm. This is the 11th reported case of delayed visual loss following dopaminergic treatment of prolactinoma. Recovery of vision always occurs with reduction of the medication dosage. Many patients whose prolactinomas are treated in this fashion display chiasmal prolapse, and few suffer visual loss. Considering that visual recovery occurs without a visible change in the position of the chiasm, traction is an unlikely cause of delayed visual loss. Therefore, the term chiasmal traction syndrome, used to describe visual loss with prolapsed chiasm following surgical and radiation treatment of sellar tumors, should not be applied in this setting lest it prompt consideration of surgical chiasmapexy. The proper management is reduction of the dopaminergic agonist dosage.

Dopamine Agonists↗