Intrathecal scan
Key points
- A RHISA scan is a nuclear scan test using small amounts of radioactive material (radioisotope) injected into the cerebrospinal fluid (CSF) to detect disorders of CSF circulation.
- Small amounts of radioactive material are injected into the cerebrospinal fluid at the lower spine.
- However, if you are very anxious or agitated, sedation may be necessary.
- The preparation you can provide for this test depends on your child's age and experience.
Alternative names
Radionuclide cisternogram; RHISA scan; Spinal cord scan; CSF flow scan; Cisternogram
Definition
A RHISA scan is a nuclear scan test using small amounts of radioactive material (radioisotope) injected into the cerebrospinal fluid (CSF) to detect disorders of CSF circulation.
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 cerebrospinal fluid is allowed to circulate for a time. The scanner can detect the presence of radiation emitted by the materials, and images are taken to illustrate the flow of those radioactive materials through the cerebrospinal fluid circulation.
A lumbar puncture (spinal tap) is performed. A radiopharmaceutical (material tagged with a radioisotope; in this case, usually albumin mixed with indium 111) is injected into the lumbar subarachnoid space (the space where the cerebrospinal fluid flows through the spine). The cerebrospinal fluid is allowed to circulate for a time and the tracer travels with it.
You will be scanned 4-6 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 radioisotope. There will be a series of scans, usually at 4-6 hours after injection, again at 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.
For infants and children:
The preparation you can provide for this test depends on your child's age and experience. For specific information regarding how you can prepare your child, see the following topics:
- toddler test or procedure preparation (1 to 3 years)
- preschooler test or procedure preparation (3 to 6 years)
- schoolage test or procedure preparation (6 to 12 years)
- adolescent test or procedure preparation (12 to 18 years)
How the test will feelDuring 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.
Written and revised by
Andrey Nailor, M.D.
Our doctors write and review articles for accuracy and keep them up to date.
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