Is the shunt series a dinosaur?

When a patient with a ventricular shunt presents to the ED, many times we will obtain a “shunt series.”  What is a “shunt series?”  Here is an example:

The top image shows a lateral cranial view demonstrating the intracranial portion of the shunt (#1), the shunt reservoir and valve (#2), and a portion of the extracranial portion of the shunt catheter coursing down the lateral portion of the head.  The second image is an AP cranial radiograph.  This is another view of the shunt with the advantage of better imaging of the lateral extracranial catheter coursing down the neck and upper chest.  The third image is an AP abdomen which shows the rest of the catheter’s course into the abdomen.

How are these used?  Shunt series are used to look for kinks and breaks in the course of the catheter, most often the extracranial portion.

There is controversy whether we should use our time, expense, as well as the radiation to obtain shunt series.  Their yield is very low and CT imaging of the head or nuclear medicine shuntograms are much better at detecting shunt failure.  One series of 263 patients showed that less than 1% of shunt revisions were based on the findings on the shunt series (1).  Another study in 2011 demonstrated a lack of statistical significance in shunt series and surgical revision.  CT and nuclear medicine imaging, on the other hand, showed statistical correlation with shunt revision (2).

Kinda begs the question:  should we be obtaining shunt series at all?

References

1.  Griffey RT, Ledbetter S, Korasani R.  Yield and utility of radiographic “shunt series” in the evaluation of ventricle-peritoneal shunt malfunction in adult emergency patients. Emerg Radiol 2007; 13 (6): 307-11.

2.  Lehnert BE, et al.  Detection of ventricular shunt malfunction in the ED:  relative utility of radiography, CT, and nuclear imaging.  Emerg Radiol 2011; 18 (4): 299-305.