1102 J Neurol (2011) 258:1098–1104 Fig. 4 38-year-old man who was treated 5 years previously for a right temporal anaplastic astrocytoma with chemo- and radiation therapy, now presenting with increasing epileptic activity and gradually progressive left sided hemiparesis and dysarthria. T2 weighted FLAIR MR images (a, b) showing gyral swelling and signal increase in the temporal lobe. T2 weighted MR image (c, d) showing gyral swelling and signal increase in the temporal lobe. A post- operative parenchymal defect is seen in the area of the previously treated astrocytoma. T1 weighted MR images after gadolinium administration (e, f) abnormal gyral and leptomeningeal enhancement in the temporal lobe and in the basal frontal areas. No focal enhancement in post-operative parenchymal defect. MR images 3 - months later. g, h T1 weighted MR image after gadolinium administration showing persistent gyral abnormalities but disappear- ance of abnormal enhancement. MR images 6 months after treatment for recurrent anaplastic astrocytoma using chemotherapy. i T2 weighted FLAIR MR image and j T1 weighted MR image after gadolinium administration showing persistent gyral abnormalities but disappearance of abnormal enhancement. MR images 6 months after treatment for recurrent anaplastic astrocytoma using chemotherapy. k T2 weighted MR image and l T1 weighted MR image after gadolinium administration resolution of T2 abnormalities and disap- pearance of abnormal enhancement in the deep temporal area 123 Fig. 4 continued combination of headaches in three of the four patients, as well as development of new neurological deﬁcit and sei- zures in all four patients was clinically suggestive for tumour recurrence. However, neither local tumour recur- rence, nor leptomeningeal disease were found to be the cause of the clinical deterioration. The radiological differential diagnosis of diffuse gyral signal increase and leptomeningeal enhancement as observed in these cases also includes vascular disorders such as ischemia, venous sinus thrombosis and dural arte- riovenous ﬁstula, and infection [6, 7]. Using CSF exami- nation and additional radiological techniques such as diffusion and perfusion weighted MRI and digital sub- traction angiography, these potentially treatable causes