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Objective: The aim of our study was to evaluate the metabolic profile of brain tissue of two long-term survivors of childhood brain tumors., Materials: Two males who were 25 and 33 years old at the time of examination and had been irradiated for brain tumors at the age of 17 and 13 years respectively. The first subject had been operated on radically for medulloblastoma and received craniospinal axis irradiation composed of a whole brain radiotherapy with boost to the posterior fossa (total dose (TD) = 59.4 Gy in 33 fractions) and spinal canal irradiation (TD = 30 Gy in 20 fractions) according to the protocol at the time of treatment. The second subject had previously received whole brain irradiation (TD = 45 Gy in 19 fractions) because of inoperable central region tumor of unknown histology., Methods: Short echo-time (TE = 30 ms) point-resolved spectra were obtained using a 2 T magnet. Ratios of N-acetylaspartate (NAA), choline (Cho), myo-inositol (mI), lactate (Lac) and lipids (Lip) signal intensities were calculated using the creatine (Cr) signal as an internal reference. The spectra were acquired both from the tumor bed area and uninvolved brain tissue in the first subject, and from uninvolved brain areas of frontal and occipital lobes in the second subject., Results: In both cases, MRS examination revealed ratios of NAA/Cr, Cho/Cr and mI/Cr within normal range in most spectra. Nevertheless, a slight elevation of Lac/Cr (2.47 and 1.05) and a more pronounced elevation of Lip/Cr proportions (45.77 and 3.97 respectively, in uninvolved sites) were detected in both patients., Conclusions: Metabolic parameters correlated with neuronal function (NAA/Cr) and cell membrane metabolites turnover (Cho/Cr) seem to recover to normal values in long-term survivors of brain tumors. Lac/Cr and Lip/Cr proportions could be considered parameters indicating permanent radiation-induced brain damage; however, this proposal requires further investigation.

The aim of the study was the functional neurodevelopmental assessment of children with posterior fossa tumors, specifically examining whether tumor location in particular cerebellar structures determines particular neuropsychological deficits. The examined group consisted of 34 children treated between 1999 and 2007 at the Division of Pediatric Neurosurgery Silesian University Medical School in Katowice, Poland. Twelve girls and 22 boys between 5 and 21 years of age were examined. The mean age was 12.3 years. There were 21 total and 8 subtotal resections of tumor, and marsupialization was performed in cases of arachnoid cysts. Hydrocephalus in 19 patients was fixed surgically. Histopathological diagnoses of tumors were as follows: 4 medulloblastomas, 8 pilocytic astrocytomas, 6 fibrillary astrocytomas, 1 anaplastic astrocytoma, 2 oligodendrogliomas, 4 anaplastic ependymomas, 1 choroid plexus papilloma, and 5 arachnoid cysts. The children were assessed by age-appropriate tests that examine higher mental functions such as cognitive processes, visual-spatial functions, verbal fluency, planning, sequential memory, and emotions. Additionally, speech examination and tests were performed. The clinical state of all patients was also evaluated, including a full neurological examination. Posterior fossa tumors can disturb normal development of higher mental functions, especially in the development of linguistic and emotional traits. Our study aimed to better understand the functional anatomy of the cerebellum in the context of behavioral changes. Exploration of the consequences of damage to posterior fossa structures may lead to a better understanding of their function in the emotional and cognitive development of children. Moreover, this work may enable the prediction of neurobehavioral disorders and offer appropriate strategies for rehabilitation, qualification, and surgical procedures.

Objective: The aim of the study was to evaluate the incidence of postirradiation imaging changes after stereotactic radiosurgery for arteriovenous malformations (AVM) and cerebral cavernous malformations (CCM)., Material and Methods: A group of 85 patients treated for arteriovenous malformations (62 patients, 73%) and cavernomas (23 patients, 27%) between October 2001 and December 2005 was analyzed. All patients were treated with stereotactic radiosurgery with doses ranging from 8-28 Gy. After the irradiation, magnetic resonance imaging (MRI) or computed tomography (CT) was performed at 6 to 12-month intervals to assess the effects of the treatment. The mean follow-up time for the whole group was 27.3 months; AVM group -- 26 months; CCM group -- 30.9 months. All the imaging data were carefully reviewed to identify the radiological symptoms of postradiosurgical damage. T2 or FLAIR hyperintensity, T1-hypointensity and contrast enhancement on MRI and the presence of hypodense areas and contrast enhancement on CT examinations were assessed., Results: Imaging abnormalities were found in 28 (33%) patients. The symptoms of postradiosurgical damage were observed in 21 (33.9%) patients in the AVM group and 7 (30.4%) patients in the CCM group. Radiological symptoms of radiation necrosis associated with neurological deterioration were identified in two patients with cavernomas, while no radiation necrosis was found in the AVM group. Patients in whom radiological signs of focal brain edema or gliosis existed were asymptomatic., Conclusions: Radiological symptoms of postradiosurgical damage affected about one third of the irradiated patients, typically without any clinical manifestations. Patients irradiated for CCMs seem to be more prone to develop symptomatic postradiosurgical necrosis; this observation, however, requires further investigation.

Purpose: The aim of this study was to evaluate the metabolic profile of uninvolved brain tissue after treatment for pediatric brain tumors., Material: A group of 24 patients aged 4-18 years was analyzed after combined treatment for brain tumors. In this group, there were nine medulloblastomas, seven low-grade gliomas, three high-grade gliomas, two ependymomas and three children with conservatively treated diffuse brainstem gliomas., Methods: Short echo-time (TE = 30 ms) point-resolved spectra were acquired using a 2 T clinical scanner (Elscint Prestige). The ratios of signal intensities for N-acetylaspartate (NAA), choline (Cho), myo-inositol (mI), lactate (Lac), and lipids (Lip) were calculated using the creatine (Cr) signal as an internal reference. The spectra were acquired both from the tumor bed and from contralateral uninvolved brain tissue; only control spectra were analyzed. The first examination was made between the third and sixth month after therapy (24 spectra), the second examination occurred 8-12 months after treatment (15 spectra available), and the third was performed approximately 18 months after completion of therapy (eight spectra available). The results were compared using the t-test for dependent samples., Results: At all time points, the metabolite ratios showed alterations indicating brain tissue damage. The most important were the decrease of NAA/Cr and increase of Lac/Cr and Lip/Cr ratios. The mean NAA/Cr values were 0.91, 0.91, and 0.86, respectively, for the three examinations, while the Lac/Cr and Lip/Cr values were 1.66, 2.11, 1.19 and 12.24, 12.05, 5.69, respectively. Interestingly, in children with supratentorial tumors, a significant increase in NAA/Cr value was observed (from 0.82 to 1.11 in the first and second examinations, respectively; p = 0.0487), which may be indicative of neuronal function recovery., Conclusions: MRS examinations of uninvolved brain tissue indicate long-lasting metabolic disturbances. However, the NAA/Cr ratio increase may be a sign of at least partial recovery of metabolic function of the brain.

Abstract: Aims: Most papers dealing with radiosurgery for cerebral arteriovenous malformations (AVMs) present the results of gamma-knife treatment, whereas linac radiosurgery is becoming increasingly popular. Moreover, there is still much uncertainty about the rationale of combined endovascular and radiosurgical treatment. The aims of this study were to evaluate obliteration and rebleeding rates, and to determine factors influencing obliteration and adverse effects after linac-based stereotactic radiosurgery for cerebral AVMs. Materials and methods: Records of 62 consecutive patients were analysed. Thirty-one had partial embolisation, five surgery, 29 had no prior treatment. The mean follow-up was 28.4 months. The mean volume treated was 11.7cm3 and included embolised portions of AVMs. Actuarial obliteration rates and annual bleeding hazard rates after radiosurgery were calculated using Kaplan–Meier survival and life table analyses. Results: Actuarial obliteration rates after 1, 2 and 3 years of follow-up were 17, 36 and 40%, respectively. Prior embolisation did not influence the obliteration rate. In 77.3% of patients, obliteration occurred during the first 2 years of follow-up. Annual bleeding hazard rates after stereotactic radiosurgery were 3.4 and 1.1% during the first and second year of follow-up, respectively. Non-symptomatic imaging abnormalities were detected in 33.9% of patients after a median time of 8.8 months. The Spetzler–Martin grade, AVM score, radiation dose, volume and AVM nidus < 3cm significantly influenced the probability of obliteration. A dose less than 15Gy significantly reduced the probability of obliteration. Conclusion: At least a 3 year follow-up is required to accurately assess the outcome. The best effects of the treatment are achieved for small (<3cm), low-grade lesions with a low AVM score. The bleeding risk after stereotactic radiosurgery gradually decreases. [Copyright &y& Elsevier]