RHISA scan
Alternative names:
cisternogram; CSF flow scan; intrathecal scan; radionuclide cisternogram; spinal cord scan
How the test is performed:
A RHISA scan is a type of nuclear scan. Small amounts of radioactive material are injected into the cerebrospinal fluid at the lower spine. The CSF is allowed to circulate for a time. The scanner can detect the presence of radiation emitted by the materials, and serial images are taken to illustrate the flow of those radioactive materials through the CSF circulation.
A lumbar puncture (spinal tap) is performed. A radiopharmaceutical (material tagged with a radioisotope; in this case, usually albumin that has been mixed with indium 111) is injected into the lumbar subarachnoid space (the space where the CSF flows through the spine). The CSF is allowed to circulate for a time and the tracer travels with the flow of CSF.
You will be scanned 4 to 6 hours later. You are asked to lie flat on a table and are placed beneath the arm of the scanner (which resembles an X-ray machine). The scanner detects the presence of radiation from the isotope. There will be a series of scans, usually at 4 to 6 hours after injection, 24-hours after injection, and possibly again at 48 and 72 hours after injection.
You should lie flat after the lumbar puncture (to help prevent headache from the lumbar puncture). No other special care is usually necessary.
How to prepare for the test:
No preparation is usually necessary. However, if you are very anxious or agitated, sedation may be necessary.
You must sign a consent form. You will wear a hospital gown (to make the spine more accessible). Remove jewelry or metallic objects before the scan.
Infants and children:
The physical and psychological preparation you can provide for this or any test or procedure depends on your child's age, interests, previous experience, and level of trust. For specific information regarding how you can prepare your child, see the following topics as they correspond to your child's age:
How the test will feel:
During lumbar puncture, the lower back over the spine is numbed with an anesthetic. However, many people find lumbar puncture somewhat uncomfortable, usually because of the pressure on the spine during insertion of the needle.
The scan is painless, although the table may be cold or hard. No discomfort is produced by the radioisotope or the scanner.
Why the test is performed:
To detect abnormalities of CSF circulation.
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