Assessment of CSF shunts by Doppler ultrasound.

Doppler ultrasound was used to detect flow through 160 C.S.F. shunt systems, 94 without suspected blockage, 62 with suspected blockage. An accuracy of 87% was achieved and we found this test helpful in clinical management in a significant number of cases. The test can distinguish between blockage of proximal and distal catheters and in certain situations can indicate infection of the distal catheter. Follow-up is continuing to determine the reliability of this technique in deciding whether asymptomatic patients are valve-dependent or not. The test is simple to learn and noninvasive.