The 61-year-old male patient presented with a slowly progressive change in character with mental deterioration. MR imaging show a chronic obstructive hydrocephalus caused by a large suprasellar arachnoid cyst, which is obstructing the entry to the aqueduct. The ventricles of the brain are considerably enlarged. The flow-sensitive inversion recovery sequence shows no flow in the area of the aqueduct.
The patient's change in character was completely reversed postoperatively. Fortunately, the patient's concentration and memory disorders have also improved significantly. The MRI images taken three years after the intervention show a great reduction in the size of the cyst. The entry to the aqueduct is no longer obstructed. In the flow-sensitive images, a strong flow signal can be seen both in the area of the aqueduct and in the area where the cystocisternostomy was performed. As would be expected with pre-existing chronic hydrocephalus, ventricle size has not reduced significantly.