There are several diagnostic tests that can help in diagnosing hydrocephalus. These same studies can also help evaluate the shunt system in case of malfunction or infection.

Magnetic Resonance Imaging (MRI) is a non-invasive diagnostic tool that uses radio signals and a magnet to form computer images of the brain, its ventricular system and coverings, and pathological lesions.

Computerized Tomography (CT Scan) is a technique in which tiny beams of x-ray outline the skull, brain, ventricles, and subarachnoid space. In addition to visualizing the size and shape of the ventricles, abnormalities such as tumors, cysts, and other pathology can also be seen.

Lumbar Tap Test is a technique where a specific amount of CSF is drained for a short period of time. This test is used to determine if a patient will respond with shunt placement.

Neuropsychological Tests are a series of questions and answers used to determine if there is decrease in brain functioning due to hydrocephalus.

Lumbar Infusion Test is a specialized technique in which fluid is injected into the lumbar subarachnoid space. This procedure is used in NPH patients to determine their CSF absorptive capacity.

Controlled Lumbar Drainage is a technique used to externally drain CSF over a period of several days. The test is used to determine if a patient with NPH will improve with shunt placement.

Angiography is a specialized technique in which contrast material is injected into the arteries supplying the brain. Abnormal blood vessel problems or pathological lesions can be detected with this technique.

Cisternography is a test requiring injection of a small amount of radioactive material into the CSF. This test differentiates communicating from obstructive hydrocephalus, and determines CSF flow.

Air Studies are done much less frequently today than in the past. Injection of air into the ventricles, either by direct puncture or through a spinal needle, may be necessary in certain instances.