FIG 4. 31-year-old woman after membranectomy of left temporal and right temporofrontal arachnoid cysts.

A, Transverse T2-weighted SE image (2000/80/1) shows slightly inhomogeneous, hyperintense temporal cysts (straight arrows). The frontal part of the large right-sided cyst is depicted (curved arrow).

B, Corresponding SSFP image (20/25/1) of the same section clearly shows a jet phenomenon with distinct signal reduction arising from the right prepontine and left chiasmatic cisterns, indicating communication between the cysts and cisterns (black arrows). Marked signal reduction results from moving CSF in the prepontine cistern (white arrow). The contents of the arachnoid cysts appear, with local flow attenuation, more inhomogeneous in the SSFP image (20/25/1) owing to higher sensitivity to turbulent flow.

C and D, Transverse (C) and coronal (D) CT cisternograms show homogeneous contrast enhancement within the basal cisterns and both the left temporal and right temporofrontal cysts. The regions of bilateral membranectomy are indicated by arrows. The coronal image also shows a frontal part of the right cyst (small arrow).