1/3. radiation-induced aneurysm and moyamoya vessels presenting with subarachnoid haemorrhage.A rare case of a ruptured internal carotid artery (ICA) aneurysm, with ICA stenosis and moyamoya vessels, was diagnosed in a young female patient after radiotherapy for optic glioma. Retrospective analysis revealed that an extraordinarily high dose of radiation (110 Gy) had been delivered to the area around the ICA in two therapeutic sessions. Clipping and wrapping of the aneurysm were performed and the patient made a good recovery. A review of the literature suggested that rupture of radiation-induced aneurysms is a rare event, but may be fatal. Considerable care must therefore be taken when delivering high-dose radiation to cerebral arteries. We suggest that the incidence of radiation-induced moyamoya vessels is higher in younger patients.- - - - - - - - - - ranking = 1keywords = haemorrhage, cerebral (Clic here for more details about this article) |
2/3. diffusion MRI in neurofibromatosis type 1: ADC evaluations of the optic pathways, and a comparison with normal individuals.In a control group of 12 normal children (ages ranging from 9 months to 3 years; mean=1.6 years) the mean apparent diffusion coefficient (ADC) value of the normal white matter, obtained from automatically generated ADC maps, was 0.84 /- 0.14 x 10(-3)mm(2)/s. A patient with neurofibromatosis type 1 with bilateral optic gliomas, and extensive optic pathway involvement was evaluated by diffusion MRI. Multiple measurements of ADC values throughout the involved optic radiations revealed a higher mean value: 1.16 /- 0.06 x 10(-3)mm(2)/s than that of the normal white matter, suggesting relatively high molecular motion in these regions, probably representing myelin vacuolization. ADC evaluation of a thalamic hamartoma revealed a lower value (=1.06 x 10(-3)mm(2)/s) than this. The mean ADC value obtained from multiple measurements of the enlarged optic chiasm, and intraorbital portions of the nerve was similar (=0.81 /- 0.09 x 10(-3)mm(2)/s) to that of the normal cerebral white matter of the control cases. It appears that diffusion imaging can be useful in evaluation of optic pathway involvement in NF1, and might contribute to differentiating optic gliomas from hamartomas, and myelin vacuolization, however, further studies will be required for assessing the role of diffusion imaging in such lesions.- - - - - - - - - - ranking = 0.056487823666099keywords = cerebral (Clic here for more details about this article) |
3/3. ophthalmic artery occlusion secondary to radiation-induced vasculopathy.A 35-year-old man with neurofibromatosis type 1 (NF1) had a left ophthalmic artery occlusion that caused no light perception OS 28 years after having been treated with external beam radiation therapy for a presumed glioma of the right optic nerve and chiasm. Clinical and imaging findings were consistent with radiation-induced cerebral vasculopathy. This ophthalmic complication has never been reported, despite the common occurrence of severe carotid-ophthalmic artery junction stenosis after radiation in NF1 patients. Even though modern radiation techniques limit collateral damage, this modality should be used with discretion in NF1 patients, given the vulnerability of their immature cerebral vasculature to radiation.- - - - - - - - - - ranking = 0.1129756473322keywords = cerebral (Clic here for more details about this article) |