What is the role of isotope cisternography in surgical care for normal pressure hydrocephalus (NPH)?

Updated: Oct 19, 2018
  • Author: Michael J Schneck, MD, MBA; Chief Editor: Selim R Benbadis, MD  more...
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Answer

Another modality without significant current use is isotope cisternography. The method involves injecting a radiolabeled isotope into the CSF space. Using this method, the excretion of the isotope can be monitored. Lack of visualization of the isotope over the brain (ie, impaired absorption of the arachnoid villa) suggests a diagnosis of NPH. This test is rarely used due to the low positive predictive value with regards to shunt-responsiveness.

The clinical usefulness of cisternography was evaluated in a large-scale study (n=76) by Vanneste et al. [22] The predictive value of a scale based on combined clinical and CT scan criteria was established first, followed by an assessment of the predictive value of cisternography. Predictions based on cisternograms were identical to those of the clinical/CT scan scale in 43%, better in 24%, and worse in 33%. This suggests that cisternography does not improve the diagnostic accuracy of combined clinical and CT scan criteria in patients with presumed normal pressure hydrocephalus.


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