Magnetic Resonance Perfusion Dynamics in Arachnoid Cysts: Insights from Pre- and Postendoscopic Intervention.

Arachnoid cysts by virtue of their volume and intracystic tension, produce local mass effect, and impair the perfusion of surrounding brain parenchyma.The magnetic resonance (MR) perfusion parameters cerebral blood flow (CBF), relative cerebral blood volume (rCBV), and mean transit time (MTT) of brain parenchyma contiguous with the arachnoid cyst were compared with corresponding contralateral hemisphere. Twenty cases of arachnoid cyst were treated using endoscopic techniques. The perfusion changes in parenchyma were assessed 3 months postoperatively. Clinical outcomes were assessed at 6 months' postsurgery.Headache was the predominant symptom (85%), with Sylvian fissure representing the most frequent anatomical location (65%). Endoscopic procedure was successful in 80% of the cases, whereas 20% of the cases required conversion to minicraniotomy and microsurgical cyst excision. Preoperatively, mean CBF (mL/100 g/min), rCBV (mL/100 g), MTT (seconds) in perilesional brain area were 42.58 ± 7.17, 4.48 ± 1.25, 5.56 ± 1.72, respectively, and 3 months postoperatively were 45.83 ± 8.87, 4.48 ± 1.62, 4.37 ± 1.68, respectively. The mean CBF (mL/100 g/min), rCBV (mL/100 g), MTT (seconds) in corresponding contralateral hemisphere was 46.77 ± 10.85, 4.29 ± 1.35, 5.24 ± 1.104, respectively, whereas postoperatively they were 46.29 ± 8.49, 5.03 ± 1.16, 5.49 ± 1.97, respectively. The p-value, however, was not significant. Headache improved in 87.5%, whereas seizure in 60% of the cases.Endoscopic treatment of arachnoid cyst is an optimally invasive procedure. The perfusion study is a valuable tool in evaluation of arachnoid cysts. MR perfusion highlights regions of impaired blood flow and focal brain dysfunction. Additionally, changes in perfusion can help assess the therapeutic impact of surgery on the compressed brain tissue.