1. VP Shunt Patency
Amanda Sachs, R.T. (MR)
Nuclear Medicine Technology Directed Practice III
College of Allied Health Sciences
University of Cincinnati
3. ★ What is “VP”?
○ Ventriculoperitoneal
■ shunt moves CSF from the ventricles to the peritoneum in the
abdominal cavity where it can be absorbed
★ CSF shunts are placed, usually at a young age, to treat
symptoms of hydrocephalus
○ the shunt moves excess CSF fluid out of the ventricles to
decrease the amount of CSF in the brain, thus decreasing
hydrocephalus
★ “The shunt system consists of a reservoir with a valve
placed beneath the soft tissues of the head, a proximal
(afferent) tubing line leading from one of the ventricles to
the reservoir, and a distal (efferent) tubing line leading
from the reservoir to the peritoneal cavity” (Macdonald &
Burrell, 2009)
All about shunts
4. Indications
★ Suspect of a malfunctioning CSF shunt
○ hydrocephalus-related symptoms
■ increase in intracranial pressure
■ mental instability
■ urinary incontinence
■ gait instability
■ headaches
■ coma
■ and many others
5. ★ If patient has a possibility of current infection
or general illness, VP shunt study should be
delayed until patient is well again due to the
risk of meningitis and other infection
★ Patient should not be pregnant or
breastfeeding
○ Female patients of childbearing age must be able to
prove they are not pregnant (by institutional policy)
○ If breast feeding, patient must make special
preparations ahead of time
★ Any recent nuclear medicine studies using Tc-99m
or In-111 may interfere with this study
Contraindications
6. ★ Area of the injection site (over the shunt
reservoir) must be shaved and cleansed
★ “A focused history containing the following
elements should be obtained:
○ History of neurologic procedures, including
shunt
○ History of hydrocephalus or seizures
○ symptoms of head pressure or pain
○ Problems with balance or memory
○ Results of other diagnostic tests” (Farrell, et al.)
★ No diet or medication restrictions
Patient Preparation
7. ★ Tc-99m DTPA (preferred), In-111 DTPA, or,
rarely,Tc-99m pertechnetate may be used for
imaging of shunts
○ Tc-99m DTPA
■ 0.5mCi (0.5-1.0mCi)
● technically Tc-99m DTPA is not approved for intrathecal
injections and “should be used with caution” (Farrell, et al.)
○ In-111 DTPA
■ 75-300 uCi (depending on the the site of the shunt)
Radiopharmaceutical Information
8. ★ Dose administered by a physician
★ Patient is sitting upright
★ Injected intrathecally into shunt
○ through rubber reservoir of shunt
■ usually located: on the right side of the head; behind the
ear, on top of the head, or the posterior portion of the
head; and usually a few centimeters below where the
initial incision site during surgery was.
○ a small amount, bolus, is all that may be injected as “to
ensure minimal disruption of the normal CSF flow”
(Macdonald & Burrell, 2009).
■ 0.3-0.5ml
○ CSF should NOT be removed by a syringe during this
procedure
Radiopharmaceutical Administration
9. ★ Patient Supine after injection
★ Immediate pictures
○ Anterior and Laterals
○ centered over head
○ 1 minute picture
○ special attention to number of counts in that 1 minute
★ Marker Picture
○ Lateral
■ slowly trace a radiopharmaceutical marker around the scalp
■ also place marker on each canthus (outside corner of the eyes) for a few seconds
○ Repeat for Anterior
★ Anterior pictures every 2 minutes for 10 minutes
★ Anterior Images every 5 minutes for at least 20 minutes
○ alternating between imaging the abdomen (where the shunt empties) and the
head
★ “If activity is not passing down the tube [or] is not clearing, the patient
should be placed in an upright position and/or the shunt should be
pumped” and the series of images would be repeated
per University Hospital protocol
Imaging Protocol (In-111 DTPA)
10. ★ Photopeaks at 173 and 247 keV
★ 15% window
★ Medium Energy High Resolution Collimators
★ 128 x 128 Matrix
per University Hospital
Acquisition Parameters(In-111 DTPA)
11. ★ 30 minute dynamic study
○ 60 images 30 seconds each or 1 minute/frame for
20 minutes
○ Anterior images
★ Planar 10 minutes/view
Imaging Protocol (Tc-99m DTPA)
12. ★ LFOV camera
★ Low Energy High Resolution collimators
★ photopeak at 140 keV
○ 20% window
★ 128 x 128 matrix
Acquisition Parameters (Tc-99m DTPA)
13. ★ activity in shunt
reservoir
★ activity along entire
course of shunt
tubing into the
peritoneal cavity
★ In Tc-99m DTPA,
kidney visualization
is normal for shunt
patency
Normal vs. Abnormal Study
★ reflux into ventricles
of the brain
★ early termination of
shunt tubing activity
★ any signs of
obstruction
15. ★ “Sum the dynamic images and display for
optimal visualization of the area of interest”
(Farrell, et. al)
★ Processing these images involves labeling the
markers (scalp, canthus, etc.)
★ Images should be inverted so that hot areas
are dark and background is lighter
★ Label the area imaged on display page
○ examples: Anterior head, anterior abdomen,
Lateral chest, etc.
★ Label the times of the images
Processing
16. Campellone, J. (2013, October 29). Ventriculoperitoneal shunting (D. Zieve, Ed.). Retrieved July 17, 2015,
from http://www.nlm.nih.gov/medlineplus/ency/article/003019.htm
CSF Shunt Scintigraphy. (2014, October 1). Retrieved July 8, 2015, from
http://www.sh.lsuhsc.edu/raddept/pdf/sec18/Rad Proc 18.8.7.6.pdf
Farrell, M., Mantel, E., Basso, D., Thomas, K., & Kerr, B. (n.d.). Quick-reference protocol manual for nuclear
medicine technologists.
Hydrocephalus and Ventriculoperitoneal (VP) Shunt [Medical Illustration]. Retrieved from
http://findlaw.doereport.com/generateexhibit.php?ID=9550&ExhibitKeywordsRaw=&TL=&A=42409
Macdonald, A., & Burrell, S. (2009). Infrequently Performed Studies in Nuclear Medicine: Part 2. Journal of
Nuclear Medicine Technology, 1-3. Retrieved July 8, 2015, from
http://interactive.snm.org/docs/Infrequently%20Performed%20Studies%20Part%202.pdf
Nuclear Medicine Shunt Patency. (n.d.). Retrieved July 7, 2015, from
http://www.hopkinsmedicine.org/neurology_neurosurgery/centers_clinics/hydrocephalus/procedures/nuclear_medi
cine_shunt.html
University Hospital
Ventriculoperitoneal Shunt Tap. (n.d.). Retrieved July 17, 2015, from
http://emedicine.medscape.com/article/81058-overview#a6
Ventriculoperitoneal Shunt. (n.d.). Retrieved July 17, 2015, from
http://www.fpnotebook.com/Neuro/Surgery/VntrclprtnlShnt.htm
References
