Cisternography, Radionuclide (CSF Flow Studies, CSF Flow Scan)

Norm of Cisternography, Radionuclide (CSF Flow Studies, CSF Flow Scan)

Normal cerebrospinal fluid (CSF) flow patterns at specific times after intrathecal injection of radiographic material into the lumbar area of the spinal cord.
1 hour: Basal cisterns.
3–4 hours: Radioactivity has reached the cerebral area and begun to spread to the ventricles and subarachnoid area.
24 hours: The flow of radioactivity should be complete to convexities or subarachnoid areas, without leakage or obstruction that would interfere with bilateral symmetry of flow.
48 hours: Radioactivity is primarily diffuse over the vertex but not in the brainstem area because it has been absorbed into the blood circulation. Symmetry is normal.

 

Usage of Cisternography, Radionuclide (CSF Flow Studies, CSF Flow Scan)

Brain atrophy; communicating hydrocephalus; suspected hydrocephalus related to CSF flow blockage (that is, tumor, cyst, subdural hematoma); CSF leakage (rhinorrhea); cerebrospinal fistulas; CSF leaks after spontaneous intracranial hypotension, trauma, or neurosurgery; identification of dural tear site with basal skull fracture; evaluation of the patency of a CSF shunt; and work-up of central nervous system symptoms such as personality changes, behavioral changes, and other neurologic changes.

 

Description of Cisternography, Radionuclide (CSF Flow Studies, CSF Flow Scan)

A nuclear medicine study of the brain and cerebral blood flow. Injection of a radioisotope into the subarachnoid space through a cisternal or lumbar puncture. The head is scanned at regular intervals to determine the amount of time it takes for the radioisotope to clear from the circulating CSF. Several views are taken at specific times over 24–48 hours.

 

Professional Considerations of Cisternography, Radionuclide (CSF Flow Studies, CSF Flow Scan)

Consent form IS required for the lumbar puncture, the radioactive injection, or the injection by cisternal puncture.

Risks
Same as for Lumbar puncture.
Contraindications
In elevated cerebrospinal fluid pressure; skin infection in lumbar or cisternal area.
Precautions
During pregnancy, risks of cumulative radiation exposure to the fetus from this and other previous or future imaging studies must be weighed against the benefits of the procedure. Although formal limits for client exposure are relative to this risk to benefit comparison, the United States Nuclear Regulatory Commission requires that the cumulative dose equivalent to an embryo/fetus from occupational exposure not exceed 0.5 rem (5 mSv). Radiation dosage to the fetus is proportional to the distance of the anatomy studied from the abdomen and decreases as pregnancy progresses. For pregnant clients, consult the radiologist/radiology department to obtain estimated fetal radiation exposure from this procedure.

 

Preparation

1. Inspect the lumbar and cisternal areas for skin infection.
2. Obtain povidone-iodine solution, 1%–2% lidocaine, a needle, a syringe, radionuclide, and a sterile lumbar puncture tray including a spinal needle.
3. Elevated CSF pressure should be ruled out before this procedure.

 

Procedure

1. Lumbar injection:
   • a. The client is placed in a lateral position with knees drawn up and chin placed on the chest. A lumbar puncture is performed, and CSF pressure is measured. A radionuclide (indium-111, ytterbium-169, iodine-131 bound to RISA) is injected into the lumbar spine space.
   • b. The client is then returned to a hospital room and usually must lie flat between studies, especially for the first series.
   • c. Cisternograms or radiographic scans are completed at 4, 24, and 48 hours.
   • d. The progress and flow pattern of the radiographic material is then studied for diagnostic purposes.
2. Cisternal injection:
   • a. Using the lumbar puncture set, a puncture is made directly into the cisterna magna at the base of the skull. A radionuclide (indium-111, ytterbium-169, iodine-131 bound to RISA) is injected into the cisterna magna.
   • b. Cisternograms are obtained in minutes, and subsequent studies are performed in 24 and 48 hours.

 

Postprocedure Care

1. The client should lie flat for 1–4 hours after the injection.
2. Observe for headache or neurologic changes.
3. Return the client, when scheduled, to the nuclear medicine department.

 

Client and Family Teaching

1. Notify the nurse or physician of any complaints of headache, dizziness, or nausea.

 

Factors That Affect Results

1. Movement during the scan obscures the views.
2. Improper injection may cause inadequate visualization.

 

Other Data

1. Cisternography is an expensive, invasive test.
2. If improper injection (rather than leak) is suspected, the study should be repeated after at least 1 week. A radiograph of the spine may be used to study a suspected leak in that area.
3. Health care professionals working in a nuclear medicine area must follow federal standards set by the Nuclear Regulatory Commission. These standards include precautions for handling the radioactive material and monitoring of potential radiation exposure.