PubMed Health⌕ Search

Biomedical subjects

L Goumnerova

Publications and source records attributed to L Goumnerova.

18 recordsLinked to original sources
PubMed2002

Multiparametric MR assessment of pediatric brain tumors.

MR assessment of pediatric brain tumors has expanded to include physiologic information related to cellular metabolites, hemodynamic and diffusion parameters. The purpose of this study was to investigate the relationship between MR and proton MR spectroscopic imaging in children with primary brain tumors. Twenty-one patients (mean age 9 years) with histologically verified brain tumors underwent conventional MR imaging, hemodynamic MR imaging (HMRI) and proton MR spectroscopic imaging (MRSI). Fourteen patients also had diffusion-weighted MR imaging (DWMRI). Metabolic indices including choline-containing compounds (Cho), total creatine (tCr) and lipids/lactate (L) were derived by proton MRSI, relative cerebral blood volume (rCBV) by HMRI, and apparent tissue water diffusion coefficients (ADC) by DWMRI. Variables were examined by linear regression and correlation as well as by ANOVA. Cho (suggestive of tumor cellularity and proliferative activity) correlated positively with rCBV, while the relationship between Cho and ADC (suggestive of cellular density) was inverse ( P<0.001). The relationship between rCBV and ADC was also inverse ( P=0.004). Cho and lipids (suggestive of necrosis and/or apoptosis) were not significantly correlated ( P=0.51). A positive relationship was found between lipids and ADC ( P=0.002). The relationships between Cho, rCBV, ADC and lipids signify that tumor physiology is influenced by the tumor's physical and chemical environment. Normalized Cho and lipids distinguished high-grade from low-grade tumors ( P<0.05). Multiparametric MR imaging using MRSI, HMRI and DWMRI enhances assessment of brain tumors in children and improves our understanding of tumor physiology while promising to distinguish higher- from lower-malignancy tumors, a distinction that is particularly clinically important among inoperable tumors.

Brain↗
PubMed2001

Stereotactic radiotherapy for pediatric intracranial germ cell tumors.

PURPOSE: Intracranial germ cell tumors are rare, radiosensitive tumors seen most commonly in the second and third decades of life. Radiotherapy alone has been the primary treatment modality for germinomas, and is used with chemotherapy for nongerminomatous tumors. Stereotactic radiotherapy techniques minimize the volume of surrounding normal tissue irradiated and, hence, the late radiation morbidity. This study reports our experience with stereotactic radiotherapy in this group of tumors. METHODS AND MATERIALS: Between December 1992 and December 1998, 18 patients with intracranial germ cell tumors were treated with stereotactic radiotherapy. A total of 23 histologically proven tumors were treated. Thirteen patients had a histologic diagnosis of germinoma, and 5 patients had germinoma with nongerminomatous elements. Of those patients with a histologic diagnosis of germinoma, 5 had multiple midline tumors. The median age of the patients was 12.9 years (range, 5.6-17.5 years). RESULTS: A boost using stereotactic radiotherapy was delivered to 19 tumors following whole-brain radiation in 8 cases and craniospinal radiation in 11 cases. Three tumors were treated with stereotactic radiotherapy to the tumor volume alone following chemotherapy, and 1 tumor received a boost using stereotactic radiosurgery following craniospinal radiation. A median dose of 2520 cGy (range, 1500-3600) cGy was given to the whole brain, and a median dose of 2160 (range, 2100-2600) cGy was given to the spinal field. The median boost dose to the tumor was 2600 (range, 2160-3600) cGy, given by stereotactic radiotherapy delivered to the 95% isodose line. At a median follow-up time of 40 (range, 12-73) months, no local or marginal recurrences were reported in patients with germinoma. Two patients with nongerminomatous tumors have relapsed. One had elevation of tumor markers only at 37 months following treatment, and the other had persistent disease following chemotherapy and radiation therapy. Eight patients documented pituitary-hypothalamic dysfunction; in 7 (87.5%) of these patients, the dysfunction was present before commencing radiotherapy. Four patients (22%) developed newly diagnosed diabetes insipidus following surgery. Three patients (17%) received antidepressant medication at follow-up. CONCLUSION: Our series shows that stereotactic radiotherapy is achievable and well tolerated in this group of patients. Longer follow-up is required to fully assess the impact on long-term toxicity. Psychologic assessment of mood and affect should be performed as part of routine follow-up in this group of adolescent children.

Adolescent↗
PubMed2001

Proton magnetic spectroscopic imaging of the child's brain: the response of tumors to treatment.

Our aim was to determine and/or predict response to treatment of brain tumors in children using proton magnetic resonance spectro-scopic imaging (MRSI). We studied 24 patients aged 10 months to 24 years, using MRI and point-resolved spectroscopy (PRESS; TR 2000 TE 65 ms) with volume preselection and phase-encoding in two dimensions on a 1.5 T imager. Multiple logistic regression was used to establish independent predictors of active tumor growth. Biologically vital cell metabolites, such as N-acetyl aspartate and choline-containing compounds (Cho), were significantly different between tumor and control tissues (P < 0.001). The eight brain tumors which responded to radiation or chemotherapy, exhibited lower Cho (P = 0.05), higher total creatine (tCr) (P = 0.02) and lower lactate and lipid (L) (P = 0.04) than 16 tumors which were not treated (except by surgery) or did not respond to treatment. The only significant independent predictor of active tumor growth was tCr (P < 0.01). We suggest that tCr is useful in assessing response of brain tumors to treatment.

Adolescent↗
PubMed2001

Measurements of intraventricular pressure in a patient shunted from the ventricle to the internal jugular vein against the direction of blood flow (the El-Shafei shunt).

OBJECT: After demonstrating the anti-siphoning properties of a distensible tube in vitro, El-Shafei constructed a shunting system that directs CSF flow into the internal jugular vein against the flow of blood. Though clinically effective, the in vivo pressure dynamics of this type of shunt system have not been investigated. METHODS: After failure at multiple other extracranial absorptive sites, an 18-year-old woman was shunted from the lateral ventricle to the internal jugular vein against the direction of blood flow. The shunt system contained an in-line noninvasive telemonitor allowing examination of postural intracranial pressure dynamics in the awake state. This shunt system demonstrated postural pressure dynamics that were consistent with a stringent nonsiphoning shunting system. CONCLUSIONS: These observations validate the use of the El-Shafei shunt placement as a biologically nonsiphoning CSF absorptive system. In addition, the stringency of the anti-siphoning properties of the internal jugular vein open the possibility of preferentially using this shunting system in patients who clearly exhibit symptoms of shunt overdrainage.

Adolescent↗
PubMed1998

Tectal tumors of childhood: clinical and imaging follow-up.

PURPOSE: This study was done to determine which clinical and imaging findings best correlate with outcome in children with tectal tumors. METHODS: A retrospective review was done of the medical records and imaging studies of 32 children (16 boys and 16 girls; mean age, 8 years) with tectal tumors. Eight children had CT, 11 had MR imaging, and 13 had both CT and MR studies. Findings from surgical and pathologic reports as well as from follow-up examinations (mean follow-up period, 5 years; range, 3.6 months to 17 years) were included in the review. RESULTS: All patients had hydrocephalus and all but one required CSF diversion. The tectum was the center of the tumor in all cases and the majority of the tumors appeared isodense on CT scans, isointense on T1-weighted MR images, and hyperintense on T2-weighted images. Twenty patients required no further treatment. In this group, the mean maximum tumor diameter was 1.8 cm and enhancement occurred in two cases. At follow-up, 18 patients had stable tumor size, one had an increase in tumor size with cyst formation but no worsening of symptoms, and one had a decrease in tumor size. Twelve patients required further treatment (excision and/or radiotherapy) because of progression as indicated by either increased tumor size or worsening of symptoms. In this group, the mean maximum tumor diameter was 2.5 cm and contrast enhancement occurred in nine cases. Further follow-up in this group showed decreased tumor size in eight and stable residual tumor in three. CONCLUSION: Tectal tumors in childhood have variable behavior. MR imaging assists in the clinical determination of which children need treatment beyond CSF diversion. Larger tumor size and enhancement are radiologic predictors of the need for further treatment.

Adolescent↗
PubMed1997

Diencephalic syndrome: clinical features and imaging findings.

PURPOSE: To emphasize the importance of imaging in children with diencephalic syndrome due to hypothalamic/chiasmatic astrocytomas. METHODS: Findings in nine patients (mean age, 26 months) with diencephalic syndrome and hypothalamic/chiasmatic astrocytomas were analyzed retrospectively, including reviewing clinical records, imaging examinations, and follow-up studies. RESULTS: Symptoms and signs included failure to thrive (n = 9), nystagmus (n = 3), visual field defects (n = 1), optic pallor (n = 1), emesis (n = 2), and headache (n = 1). All patients had hypothalamic/chiasmatic masses. Five patients underwent biopsy, and, in all cases, specimens showed low-grade astrocytoma. Imaging studies were available in eight patients. All tumors were large (median maximum diameter, 3.5 cm), involved the chiasm and hypothalamus, and showed homogeneous enhancement. Three patients had hydrocephalus and two had metastases. At follow-up, five patients had recurrent disease and two had died. CONCLUSION: Diencephalic syndrome is a rare cause of failure to thrive in childhood, and diagnosis of a hypothalamic/ chiasmatic astrocytoma might therefore be delayed. The astrocytomas associated with this syndrome are larger, occur at a younger age, and are often more aggressive than other astrocytomas arising in this region.

Astrocytoma↗
PubMed1996

The critical importance of stimulus intensity in intraoperative monitoring for partial dorsal rhizotomy.

During partial lumbosacral dorsal rhizotomy (PDR), intraoperative dorsal rootlet stimulation (drs) evokes motor responses, presumed to be reflexes, which are used to select rootlets for section. However, dr stimuli may also costimulate ventral root (vr) and evoke an M rather than a reflex response, the two being distinguishable only by comparison of response latencies after drs at two separate sites. In 15 consecutive spastic cerebral palsy patients undergoing PDR, we asked whether reflex and M responses were distinguishable on the basis of stimulus intensity (SI). For soleus H reflexes evoked by percutaneous tibial nerve stimulation, the SI for reflex afferents was usually subthreshold for exciting motor fibers. Similarly, for nerve roots, reflexes were evoked by drs at SIs generally less than that for M responses evoked by vr stimulation (vrs). In contrast, M responses evoked by drs required SIs that were on average 20 times greater. Finally, costimulation of contralateral vr after ipsilateral vrs occurred at SIs shown to evoke M responses after drs. We conclude that: (1) reflex and M responses evoked by drs are distinguishable on the basis of the required SI; and (2) drs employing SIs greater than required for vrs evokes M rather than reflex responses due to costimulation of ipsilateral and contralateral vr.

Cerebral Palsy↗
PubMed1996

Acquired cerebral arteriovenous malformation in a child with moyamoya disease. Case report.

The authors report a unique case involving a 2-year-old child with idiopathic moyamoya disease who presented with cerebral infarctions and seizures. On initial evaluation, computerized tomography (CT) showed a left parietal infarct and angiograms demonstrated early moyamoya disease with no evidence of arteriovenous malformation (AVM). Approximately 9 years later, angiography and magnetic resonance (MR) imaging revealed an AVM centered on the same region of the left parietal lobe. Angiographic, CT, and MR images are presented that demonstrate the progression of moyamoya disease and de novo development of the AVM in the infarct site. The possible role of angiogenesis in the etiology of acquired AVMs and moyamoya disease is discussed.

Cerebral Angiography↗
PubMed1994

Stereotactic radiotherapy for pediatric and adult brain tumors: preliminary report.

PURPOSE: Stereotactic radiotherapy is a new modality that combines the accurate focal dose delivery of stereotactic radiosurgery with the biological advantages of conventional radiotherapy (1.8-2.0 Gy/day using 25-30 fractions). The modality requires sophisticated treatment planning, dedicated high-energy linear accelerator, and relocatable immobilization devices. We report here our early experience using stereotactic radiotherapy for intracranial neoplasms. METHODS AND MATERIALS: Between June 1992 and September 1993, we treated 82 patients with central nervous system lesions using stereotactic radiotherapy, delivered from a dedicated 6 MV stereotactic linear accelerator. A head fixation frame provided daily relocatable setup using a dental plate for all patients over 8 years of age. A modified head frame, which does not require a mouthpiece, was used for children requiring anesthesia. The patients ranged in age from 9 months to 76 years. Thirty-three patients were children less than 21 years of age. Selection criteria for the protocol included: (a) focal, small (< 5 cm) radiographically distinct lesions known to be radiocurable (pituitary adenoma, craniopharyngioma, meningioma, acoustic neuroma, pilocytic astrocytoma, retinoblastoma), and (b) lesions located in regions not amenable to surgery or radiosurgery such as the brain stem or chiasm. Standard fractionation and conventional doses were delivered. Patients with low-grade astrocytoma, oligodendroglioma, or ependymoma were treated using a dose escalation regime consisting of conventional doses plus a 10% increase. RESULTS: Although follow-up is 16 months (range 3-16 months), posttreatment radiographic studies in 77 patients have been consistent with changes similar to those found after conventional radiation therapy. To date, reduction of up to 50% of the original volume has been noted in 19 out of 77 patients, and 4 patients had a complete response, 2 with dysgerminoma, and 1 each with astrocytoma and retinoblastoma. In 56 patients disease was either stable or the follow-up was too short for evaluation. While the follow-up is relatively short, there have been no in-field or marginal recurrences. The only unexpected radiographic findings were in three patients with pilocytic astrocytomas, who developed asymptomatic edema in the treatment volume. Accuracy in daily fractionation was excellent. In over 2000 patient setups with 41,000 scalp measurements, reproducibility was found to be within 0.41 mm (median) of baseline readings, allowing for precise immobilization throughout the treatment course. The treatment in all cases was well tolerated with minimal acute effects. Our stereotactic radiotherapy facility can provide fractionated therapy for 10-12 patients a day efficiently and accurately. CONCLUSIONS: The treatment and relocatable stereotactic head frames were well tolerated with minimal acute effects. No long-term sequelae have been noted, although the observation period is short. To fully define the role of stereotactic radiotherapy, we are conducting prospective studies to evaluate neurocognitive and neuroendocrine effects. We expect that this innovative approach will make a significant impact on the treatment of intracranial neoplasms, particularly in children.

Adolescent↗
PubMed1994

Surgery, radiation, and combination therapy in the treatment of childhood craniopharyngioma--a 20-year experience.

The records of 61 children treated for primary craniopharyngioma at the Children's Hospital in Boston and The Joint Center for Radiation Therapy from 1970 to 1990 were reviewed to determine if any information could be obtained regarding the efficacy of surgery versus radiotherapy or a combination of these modalities for this tumor. A select group of 9 children treated without biopsy by radiation therapy alone were all alive without disease progression at follow-up. Although 9 of the 15 children who underwent surgery alone had tumor recurrence, 7 of the 37 children treated with radiotherapy following surgery have also recurred. Treatment morbidity occurred in all groups, but the 10-year actuarial survival for all patients was 91%. Early postoperative imaging and pre- and posttreatment endocrine and neuropsychologic evaluations need to be carried out in all prospective studies of the treatment of craniopharyngioma in children.

Adolescent↗
PubMed1994

Advances in radiation therapy for craniopharyngiomas.

The overall survival for patients with craniopharyngioma is excellent. However, conventional treatments that include aggressive surgery and standard irradiation have been associated with significant morbidity. Focal radiation treatment with stereotactic radiosurgery has a role in selected cases, but may also be damaging to sensitive normal tissues such as the optic chiasm. Stereotactic radiotherapy (SRT) is a technique that allows for conventionally fractionated radiation under stereotactic guidance. Thus, highly focal and precise radiotherapy is now coupled with fractionation, enabling the treatment of selected tumors with a potentially improved therapeutic index. Dose optimization with SRT for focally discrete tumors should result in equivalent local control and survival compared to patients treated with conventional irradiation. We anticipate a significant decrease in late effects, especially neuropsychological and neuroendocrine sequelae.

Child↗
PubMed1992

A randomized controlled trial of perioperative rifampin/trimethoprim in cerebrospinal fluid shunt surgery.

A randomized, double-blind, placebo-controlled trial of perioperative rifampin-trimethoprim was undertaken at the Hospital for Sick Children from March 1984 to October 1987, in which 243 patients undergoing 300 cerebrospinal fluid (CSF) shunting procedures were randomized into groups including treatment with rifampin/trimethoprim and placebo, and then followed for a minimum of 2 years. Patients were stratified prior to randomization into those with and those without meningo-myeloceles having first insertions of their shunts, and those having revisions. Patients could be entered into the study more than once, but always received the same treatment regimen once allocation had taken place. Among the patients receiving antibiotics there was an infection rate of 12%, versus 19% among patients receiving placebo. Among the surgical procedures, the rates were 9% and 15%, respectively. Because these rates of infection were a substantial increase over the rate of 7.5% overall for the few years prior to implementation of the study, and well over any acceptable rate of infection, the study was stopped before statistical significance was reached. However, had the study continued, and the proportions of patients becoming infected remained constant, we would have been able to achieve a statistically significant difference in rates of infection, and therefore demonstrate a benefit of rifampin/trimethoprim as prophylaxis against shunt infection. Methodological problems encountered in this and other studies of prevention of CSF shunt infection will be discussed.

Adolescent↗
PubMed1987

Intracarotid infusion of PCNU (NSC: 95466): preclinical toxicological study in dogs.

The prognosis of patients with unresectable intracerebral primary and metastatic tumours that recur following cranial irradiation is poor. Chemotherapy agents have been of limited value. PCNU--a new nitrosourea, has been shown to have the optimum log P for treatment of murine intracerebral tumours. We conducted a preclinical toxicological study of intracarotid injection of PCNU in dogs. Our results show that there was no major neurological or retinal toxicity from the drug, suggesting that PCNU may be less toxic than the presently available BCNU.

Alkylating Agents↗
PubMed1985

Chronic subdural hematoma mimicking transient ischemic attacks.

A case is reported in which a chronic subdural hematoma caused recurrent episodes of neurologic dysfunction that simulated transient ischemic attacks. Possible pathophysiological mechanisms are: a subdural hematoma could cause local ischemia or focal epileptic discharges; a cerebral mass could cause cortical depression by mechanical stimulation; regional cerebral edema could cause vascular displacement and ischemia; or small repeated hemorrhages could cause transient neurologic deficits. Computer assisted tomography of the head is recommended in the differentiation of the two conditions.

Aged↗
PubMedDate not supplied

Development of symptomatic Chiari malformation in a child with craniofacial dysmorphism.

We present the case of a 28-month-old child with craniofacial anomalies who presented for evaluation of apnea. The patient had associated symptoms referable to a Chiari malformation and MRI scanning of the head and cervical spine revealed some, but not all, of the anatomical features classically associated with the Chiari II malformation. The child has mid-face hypoplasia and it appeared that his posterior fossa hypertension was partially caused by anterior compression of the brain stem as a result of the malformation at the base of the skull. The patient responded dramatically to posterior fossa decompression. Evidence from this and other cases from the literature suggests that different pathophysiological mechanisms may cause the classic Chiari malformation and/or other anatomical abnormalities in the continuum between Chiari I and II.

Arnold-Chiari Malformation↗
PubMedDate not supplied

Pediatric and adolescent oligodendrogliomas.

PURPOSE: To review the clinical and imaging findings in pediatric and adolescent intracranial pure oligodendrogliomas. METHODS: The clinical, CT, and MR data in 39 surgically proved pure oligodendrogliomas were retrospectively reviewed. RESULTS: The frontal or temporal lobes were involved in 32 (82%) cases. Seventy percent of the tumors were hypodense on CT, three-fourths were hypointense on T1-weighted images, and all were hyperintense on spin-density and T2-weighted images. Fewer than 40% of the lesions demonstrated calcification, and nearly 60% had well-defined margins. Mass effect was seen in fewer than half of the cases, and edema could be separately identified in only one case. Tumor enhancement was seen in fewer than 25%. In 39 cases after partial (3), subtotal (16), or total (20) resection, follow-up studies demonstrated stability over a mean period of 5 years. CONCLUSION: The findings in this pediatric series of pure oligodendrogliomas (without mixed cell elements) differ from previous adult series in that calcification, contrast enhancement, and edema are seen less frequently. In addition, very slow or no growth is often characteristic, and these patients have an excellent prognosis with surgical resection.

Adolescent↗