ShuntCheck Versus Radionuclide in Evaluating Shunt Function in Symptomatic NPH Patients

The primary objective is to demonstrate that the accuracy of SC and SC+MP for determining
whether a VP shunt is patent or obstructed is statistically no different than the accuracy
of the accepted standard test, radionuclide shunt patency study, when performed
simultaneously.

A secondary objective is to determine SC and SC+MP results in the presence of possible
partial obstruction, which defined as subjects with radionuclide clearance measured by T1/2
of 8 to 10 minutes.

A secondary objective is to compare ShuntCheck flow rate results to simultaneous
radionuclide clearance as measured by T1/2. A secondary objective is to demonstrate that
ShuntCheck flow rate results are statistically equivalent to simultaneous radionuclide
clearance measured by T1/2

Inclusion Criteria:

1. Adult men or women > 35 years of age;

2. Capable of providing valid signed informed consent, or has a legal guardian, health
care agent, or surrogate decision maker (according to local statutes, and
collectively referred to as "surrogates" in this protocol) capable of providing
valid, signed informed consent;

3. Possess a shunt placed for AH;

4. A radionuclide shunt patency study has been ordered because of suspected shunt
obstruction

5. Subject is willing and able to return to the treating physician for evaluation of the
outcome of the shunt patency study

Exclusion Criteria:

1. Presence of multiple shunts, or presence of more than one distal shunt catheter
(regardless of function) crossing the clavicle ipsilateral to the shunt with
suspected obstruction;

2. ShuntCheck test would interfere with standard patient care, or emergency shunt
surgery that cannot be delayed is indicated;

3. Presence of an interfering open wound or edema over any portion of the VP shunt;

4. Subject is unwilling or unable to return to the treating physician for the SPS and
ShuntCheck testing.