1/9. Radiation-induced temporary alopecia after embolization of cerebral arteriovenous malformations.alopecia after endovascular embolization of cerebral arteriovenous malformations (AVMs) is uncommon. In this report, we present a 33-year-old man who developed temporary alopecia after staged embolization of a cerebral AVM. Four days after the last procedure, this patient had hair loss over his right temporoparietal and occipial areas. No scalp erythema or other sign of dermatitis was noted. The hair regrew 2 months later. The alopecia was considered to be related to repeated exposure to radiation during embolization. The experience in this case and review of the literature suggest that interventional neuroradiological procedures may cause substantial radiation exposure to the patient. Therefore, radiation use should be limited to the least amount necessary to complete the endovascular procedure to prevent radiation-induced biological changes and morbidity. patients should be well informed of adverse effects such as alopecia.- - - - - - - - - - ranking = 1keywords = radiation-induced (Clic here for more details about this article) |
2/9. Gamma knife surgery-induced meningioma. Report of two cases and review of the literature.Gamma Knife surgery (GKS) is a minimally invasive neurosurgical technique. During the past 30 years, radiosurgery has been performed for a number of intracranial disorders with a generally low incidence of side effects. Although radiation-induced neoplasia following radiotherapy is well documented, there are few reports of this complication following radiosurgery. The authors are engaged in an ongoing project in which they are studying the delayed adverse effects of radiosurgical changes in 2500 patients with arteriovenous malformations (AVMs) treated within a 30-year period. The cases of 1333 patients treated by the senior author (L.S.) have been reviewed thus far. A subset of 288 patients in this group underwent neuroimaging and participated in clinical follow up for at least 10 years. The authors report two cases of radiosurgically induced neoplasia. In both cases the patient was treated with GKS for an AVM. Longer than 10 years after GKS, each of the patients was found to have an incidental, uniformly enhancing, dura-based mass lesion near the site of the AVM. These lesions displayed the imaging characteristics of a meningioma. Because in both cases the lesion has displayed no evidence of a mass effect, they continue to be followed using serial neuroimaging. These are the fifth and sixth cases meeting the criteria for radiation-induced neoplasms defined by Cahan, et al., in 1998. Although radiosurgery is generally considered quite safe, the incidence of radiation-induced neoplasms is not known. These cases and the few others detailed in the literature emphasize the need for long-term neurosurgical follow-up review in patients after radiosurgery.- - - - - - - - - - ranking = 3keywords = radiation-induced (Clic here for more details about this article) |
3/9. Radiation-induced edema after radiosurgery for pontine arteriovenous malformation. A case report and detection by magnetic resonance imaging.A 29-year-old woman, who had undergone stereotactic radiosurgery for a pontine arteriovenous malformation, experienced sudden onset of facial nerve palsy with trigeminal nerve disturbance 19 months after irradiation. magnetic resonance imaging revealed significant radiation-induced edema surrounding the nidus. angiography demonstrated total obliteration of the arteriovenous malformation 24 months after irradiation. Further magnetic resonance imaging studies, performed 28 months after treatment, showed that, despite the persistence of symptoms, the radiation-induced edema had subsided.- - - - - - - - - - ranking = 2keywords = radiation-induced (Clic here for more details about this article) |
4/9. Treatment of symptomatic AOVMs with radiosurgery.In spite of great success in the treatment cerebral AVMs with stereotactic radiosurgery, the role of this treatment modality in angiographically occult vascular malformations (AOVMs) is not recognized. Since the installation of the Gamma-knife, we have treated 20 cases of AOVMs by radiosurgery. There were 13 males and 7 females, the age ranged from 3 to 58 years with an average age of 34.0 years. Their clinical presentations at the onset were haemorrhage in 11, convulsive seizure in 7 and progressive neurological deficits in 2. Two cases had multiple lesions. Among 20 symptomatic lesions, 14 were located supratentorially, 4 in the brain stem and 2 in the cerebellar hemispheres. Following localization with MRI and dose planning, the lesions were treated by radiosurgery and the doses ranged from 15 to 20 Gy at the margins. follow-up studies indicate a significant control of rebleeding as well as of the convulsive seizure. Imaging studies demonstrated the shrinkage of the lesion in 3 and reduced enhancement with gadolinium-DTPA in some others. Adverse effects, chiefly related to radiation-induced oedema, occurred in 5. But they were generally mild and well controlled by medication. Thus the preliminary results indicate a certain usefulness of radiosurgery in the treatment of symptomatic AOVMs.- - - - - - - - - - ranking = 1keywords = radiation-induced (Clic here for more details about this article) |
5/9. Gamma knife radiosurgery for cerebral arteriovenous malformations: an autopsy report focusing on irradiation-induced changes observed in nidus-unrelated arteries.BACKGROUND: In radiosurgical treatment for an arteriovenous malformation (AVM), the effects of irradiation on the intranidal and perinidal angioarchitectures have seldom been analyzed histologically. An autopsy case is reported, studying an AVM treated by gamma knife radiosurgery. Postmortem studies following AVM-unrelated death were performed after a 2-year angiography had demonstrated complete nidus obliteration. Irradiation-induced changes were also observed in surrounding nidus-unrelated arteries and the choroid plexus, both of which were within the irradiation target. methods: Microscopic studies were performed using a coronal section of the brain including the center of the AVM, on which the percent isodose volume gradient, corrected with a magnification rate, was superimposed. RESULTS: This study disclosed that intimal hypertrophy can occur in a normal, AVM-unrelated pial artery due to irradiation of 10 Gy or more and that more remarkable intimal hypertrophy with fragmentation of the elastic laminae, or even complete occlusion, can occur in these arteries with 25 Gy. Similarly, irradiation-induced degeneration was present in the choroid plexus, which had been exposed to doses varying from 10 Gy to 25 Gy. CONCLUSIONS: A normal surrounding blood vessel may also be affected by high-dose, single-fraction irradiation though the abnormal vessels have been reported to be more susceptible.- - - - - - - - - - ranking = 6keywords = radiation-induced (Clic here for more details about this article) |
6/9. A diffuse white matter ischemic lesion appearing 7 years after stereotactic radiosurgery for cerebral arteriovenous malformations: case report.OBJECTIVE AND IMPORTANCE: Little information is available about radiation-induced complications occurring more than 5 years after radiosurgical treatment for arteriovenous malformations. CLINICAL PRESENTATION: We present a patient with arteriovenous malformations who experienced hemimotor weakness caused by a diffuse white matter necrotic lesion developing 7 years after gamma knife radiosurgery. The original nidus had been too large (24.1 cm3) to be totally covered and irradiated with a peripheral dose of 20 to 25 Gy. Therefore, the lower half of the nidus, which was adjacent to the major feeding artery, had been partially covered with a 30% isodose volume using two target points with an 18-mm collimator. A central dose of 70 Gy was used to obtain 21 Gy at the periphery. Complete nidus obliteration was angiographically confirmed 38 months after radiosurgery. After a 6-year uncomplicated period, this patient experienced a convulsive seizure and then mild right hemiparesis. INTERVENTION: Computed tomography demonstrated a diffuse hypodense area in the left white matter, which had not been revealed by the previous examination. With steroid treatment, this patient achieved clinical improvement, although there was no significant improvement in the computed tomography-demonstrated white matter lesion. CONCLUSION: Although the evaluation of this patient may not be sufficient and further examinations may be necessary, we tentatively conclude that the computed tomography-demonstrated hypodense lesion in this patient is a radiation-related necrotic lesion. Long-term follow-up is crucial, even after the "treatment goal" has been achieved.- - - - - - - - - - ranking = 1keywords = radiation-induced (Clic here for more details about this article) |
7/9. Delayed cyst formation after radiosurgery for cerebral arteriovenous malformation: two case reports.Two patients who underwent gamma knife radiosurgery for ruptured cerebral arteriovenous malformations (AVM) developed cystic lesions at 78 and 111 months after undergoing treatment. Both patients presented initially with intracerebral hemorrhage. In one patient, the cystic lesion was discovered during routine follow-up imaging and clinical examination revealed homonymous hemianopsia; the second patient presented with seizure and the lesion was identified more than 9 years after radiosurgery. One patient underwent resection of the nidus and histologic analysis of the resected specimen showed vessels in various stages of obliteration. The present paper discusses the possible mechanism for the delayed development of cystic lesions, and the possibility that radiation-induced vascular changes may continue in a nidus even when angiography shows complete obliteration of the nidus.- - - - - - - - - - ranking = 1keywords = radiation-induced (Clic here for more details about this article) |
8/9. Late cyst convolution after gamma knife radiosurgery for cerebral arteriovenous malformations.Although many series of patients with cerebral arteriovenous malformations (AVMs) treated radiosurgically have been published, there has been little information on cysts appearing several years after irradiation. Herein, we discuss the incidence, mechanisms and predictability of late cyst formation based on our personal experiences, as well as reported patients. The incidence of this complication, though generally considered to be 0.5% or less, may be higher than assumed. Although a breakdown of the blood-brain barrier is likely to play a major role in the formation process, the hematoma cavity itself may have the potential to become a cyst. A radiation-induced lesion appearing several years after irradiation and persisting for several years thereafter may be a warning sign of late cyst formation. Long-term follow-up, particularly using neuroimaging techniques, is necessary even after the 'treatment goal' has been achieved.- - - - - - - - - - ranking = 1keywords = radiation-induced (Clic here for more details about this article) |
9/9. Treatment of cerebral radionecrosis by hyperbaric oxygen therapy.Clinically observed adverse radiation effects (ARE) are rather uncommon, but modern imaging reveals that they are more common after radiosurgery than previously believed. Little is known about the pathogenesis, and current treatment is mostly empirical. The benefit of hyperbaric oxygen therapy (HBO) on radiation-induced bone and soft tissue necrosis is known in lesions in the maxillofacial area, the mouth and in the head and neck. HBO raises the tissue pO2 and initiates a cellular and vascular repair mechanism. This forms the basis for the hypothesis that it might also help alleviate the results of cerebral radionecrosis. This study is a preliminary attempt to test this hypothesis. Two patients with arteriovenous malformations (AVMs) were chosen for the study. They had been treated with Gamma Knife radiosurgery (GKRS) and had developed imaging signs consistent with ARE. They were treated by breathing 100% oxygen at 2.5 atmospheres absolute (250 kPa) in sessions of 60 minutes per day. This treatment was repeated 40 times in cycles of ten sessions. Both responded well to HBO, one lesion disappeared and the other was reduced significantly in size. No adjuvant steroids were given. These results give evidence that HBO has a potential value in treating ARE but further experience will be needed to confirm its definite benefit.- - - - - - - - - - ranking = 1keywords = radiation-induced (Clic here for more details about this article) |