Using phase-contrast MRI to assist in assessment of shunt function following postoperative intraventricular hemorrhage: illustrative case

Abstract

Background: Phase-contrast MRI (PC-MRI) offers a rapid, noninvasive technique to directly quantify flow through ventricular shunts, and it serves as an adjunct MRI sequence to inform decision-making in complex postoperative settings. Observations: A 19-year-old man with Dandy-Walker-associated hydrocephalus underwent proximal catheter exchange of a right-sided parietal ventriculoperitoneal shunt. Postoperatively, he developed intraventricular hemorrhage and symptomatic shunt occlusion and required emergency left frontal external ventricular drain (EVD) placement. After 5 days of drainage, the EVD was clamped and limited brain MRI with PC-MRI was performed. Shunt flow measured 21.2 ± 2.8 mL/hr, exceeding the patient's prior mean EVD output of 12 ± 6.8 mL/hr. The lateral ventricles had returned to their presymptomatic size, and the patient's symptoms resolved. These concordant findings supported shunt patency, enabling safe EVD removal, and no additional shunt surgery was required. Lessons: When ventricular size, pressure, and clinical status alone cannot conclusively establish ventricular shunt function, PC-MRI can supply a direct, quantitative measure of CSF flow. Incorporating this brief (60-second) sequence into surveillance imaging for patients with ventricular shunts may refine management decisions, avert unnecessary revisions, and improve patient safety.