A radionuclide cisternogram is a medical imaging study which involves injecting a

radionuclide A radionuclide (radioactive nuclide, radioisotope or radioactive isotope) is a nuclide that has excess nuclear energy, making it unstable. This excess energy can be used in one of three ways: emitted from the nucleus as gamma radiation; transfer ...

lumbar puncture Lumbar puncture (LP), also known as a spinal tap, is a medical procedure in which a needle is inserted into the spinal canal, most commonly to collect cerebrospinal fluid (CSF) for diagnostic testing. The main reason for a lumbar puncture is to ...

(spinal tap) into a patient's

cerebral spinal fluid Cerebrospinal fluid (CSF) is a clear, colorless body fluid found within the tissue that surrounds the brain and spinal cord of all vertebrates. CSF is produced by specialised ependymal cells in the choroid plexus of the ventricles of the bra ...

(CSF) to determine if there is abnormal CSF flow within the brain and spinal canal which can be altered by

hydrocephalus Hydrocephalus is a condition in which an accumulation of cerebrospinal fluid (CSF) occurs within the brain. This typically causes increased pressure inside the skull. Older people may have headaches, double vision, poor balance, urinary in ...

Arnold–Chiari malformation Chiari malformation (CM) is a structural defect in the cerebellum, characterized by a downward displacement of one or both cerebellar tonsils through the foramen magnum (the opening at the base of the skull). CMs can cause headaches, difficul ...

syringomyelia Syringomyelia is a generic term referring to a disorder in which a cyst or cavity forms within the spinal cord. Often, syringomyelia is used as a generic term before an etiology is determined. This cyst, called a syrinx, can expand and elongate o ...

, or an

arachnoid cyst Arachnoid cysts are cerebrospinal fluid covered by arachnoidal cells and collagen that may develop between the surface of the brain and the cranial base or on the arachnoid membrane, one of the three meningeal layers that cover the brain and t ...

. It may also evaluate a suspected leak (also known as a CSF

fistula A fistula (plural: fistulas or fistulae ; from Latin ''fistula'', "tube, pipe") in anatomy is an abnormal connection between two hollow spaces (technically, two epithelialized surfaces), such as blood vessels, intestines, or other hollow or ...

) from the CSF cavity into the nasal cavity. A leak can also be confirmed by the presence of beta-2 transferrin in fluid collected from the nose before this more invasive procedure is performed. The patient may be instructed to not eat or drink, or take medications such as

aspirin Aspirin, also known as acetylsalicylic acid (ASA), is a nonsteroidal anti-inflammatory drug (NSAID) used to reduce pain, fever, and/or inflammation, and as an antithrombotic. Specific inflammatory conditions which aspirin is used to treat in ...

or other blood thinners before the procedure. Pledgets can be inserted into the nasal cavity before the procedure when a CSF leak is suspected. The patient's spinal fluid is injected with a radiopharmaceutical tracer, such as

DTPA Pentetic acid or diethylenetriaminepentaacetic acid (DTPA) is an aminopolycarboxylic acid consisting of a diethylenetriamine backbone with five carboxymethyl groups. The molecule can be viewed as an expanded version of EDTA and is used similarl ...

tagged with indium 111, through a

(spinal tap). The tracer will diffuse up the spinal column and into the intracranial ventricles and the subarachnoid spaces around the brain. The progress of the tracer's

diffusion Diffusion is the net movement of anything (for example, atoms, ions, molecules, energy) generally from a region of higher concentration to a region of lower concentration. Diffusion is driven by a gradient in Gibbs free energy or chemical p ...

through the CSF will be recorded by a nuclear medicine

gamma camera A gamma camera (γ-camera), also called a scintillation camera or Anger camera, is a device used to image gamma radiation emitting radioisotopes, a technique known as scintigraphy. The applications of scintigraphy include early drug development ...

. Images are usually taken immediately, at 6 hours, and at 24 hours. The patient may be asked to return for 48- and 72-hour follow-up scans. The pledgets will be removed and either imaged with a gamma camera or counted using a

gamma counter A gamma counter is an instrument to measure gamma radiation emitted by a radionuclide. Unlike survey meters, gamma counters are designed to measure small samples of radioactive material, typically with automated measurement and movement of multi ...

. If the tracer has leaked onto the pledget through the skull, it will appear on the gamma camera image or register abnormal counts allowing the diagnostician to determine the location of the leak within the sinus cavity. The site of the CSF leak can be plugged with fat or muscle by

endoscopic An endoscopy is a procedure used in medicine to look inside the body. The endoscopy procedure uses an endoscope to examine the interior of a hollow organ or cavity of the body. Unlike many other medical imaging techniques, endoscopes are inser ...

surgery. Headaches following the procedure are common, but should fade in 3–5 days. Drinking caffeinated liquids, as well as

bed rest Bed rest, also referred to as the rest-cure, is a medical treatment in which a person lies in bed for most of the time to try to cure an illness. Bed rest refers to voluntarily lying in bed as a treatment and not being confined to bed because of ...

, is often recommended, though at least one scientific paper disputes the practice.

References

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External links

eMedicine entry on CSF leaks2002 paper disputing caffeine as a cure for CSF headachesInformation for DTPA In-111
Neuroimaging CSF tests