Figure 2.

A 60-year-old woman with fistulas at the torcular Herophili-left transverse - sigmoid sinus (Cognard's IIa+b type/Lal- wani's grade 3). Lateral view of the left external common carotid angiogram (A) showed the shunt flow from the occipital artery via fistulas at the torcular Herophili- left transverse - sigmoid sinus draining in a retrograde fashion into Labbe's vein. 99m-Tc ECD SPECT imaging with a gray scale (162 and 20 of the maximal and minimal gamma-ray counts, respectively) (B) demonstrated low perfusion in the left temporal lobe (arrow). T2-weighted image (C) demonstrated the high intensity with the flow void in the left temporal lobe, suggesting venous infarction with the retrograde venous reflux (arrow). ASL-MRI with a gray scale (120 and Ü of the maximal and minimal ASL values (mL / 1ÜÜ g brain tissue / minute), respectively) before treatment (D, E) also showed hypointensity (arrow on E). However, there was a discrepancy in the bilateral cerebellar hemispheres, where hyperin- tensity was seen on ASL-MRI (arrowhead on E), but no abnormal findings were seen on SPECT imaging (arrowhead on B). On days 8-20 after treatment, T2-weighted image (F) revealed the disappearance of the flow void, suggesting the resolution of the retrograde venous reflux (arrow). The ASL values decreased in the bilateral cerebellar hemispheres (arrowhead on G), whereas ASL values increased in other regions (H) compared with those observed before treatment (D, E). On days 112-120 after treatment, T2-weighted image (I) showed the atrophic change and the sustainment of high intensity in the left temporal lobe (arrow). Lower ASL values were observed in all regions (J, K), as compared to those before treatment in the corresponding regions.