Cerebral Perfusion Does Not Increase after Shunt Surgery for Normal Pressure Hydrocephalus

Area of Science:

• Neurology
• Radiology
• Medical Imaging

Background:

• Idiopathic normal pressure hydrocephalus (iNPH) is a condition where cerebral blood flow (CBF) may change after shunt surgery.
• Arterial spin labeling (ASL) is a noninvasive MRI technique used to measure CBF.

Purpose of the Study:

• To investigate if CBF increases after shunt surgery in iNPH patients using ASL.
• To determine if postoperative CBF changes correlate with symptom improvement.
• To assess if baseline CBF predicts postoperative outcomes.

Main Methods:

• Prospective study of 23 iNPH patients with baseline MRI and clinical tests.
• 18 patients underwent shunt implantation and were re-examined 3 months postoperatively.
• ASL MRI was used to measure perfusion in 12 regions of interest (ROIs).

Main Results:

• No significant increase in CBF was observed in any ROI after shunting.
• Preoperative CBF in the medial frontal cortex showed a correlation with improved urinary incontinence (r = .53, P = .022).
• No correlation was found between the change in CBF and the change in clinical symptoms postoperatively.

Conclusions:

• ASL's clinical utility in evaluating iNPH patients remains uncertain.
• ASL did not predict surgical outcomes or correlate with symptom changes after shunt surgery in this study.