These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: The reliability of the "absent cistern sign" in assessing LP shunt function.
    Author: Kulkarni AV, Chumas PD, Drake JM, Armstrong DC.
    Journal: Can J Neurol Sci; 1999 Feb; 26(1):40-3. PubMed ID: 10068806.
    Abstract:
    OBJECTIVE: One of the difficulties with lumboperitoneal (LP) shunts has been non-invasively ascertaining shunt function. It has been previously reported that in the presence of a functioning LP shunt the perimesencephalic cisterns become obliterated--the "absent cistern sign". In order to more rigorously test this association we performed a retrospective analysis of LP shunt patients at the Hospital for Sick Children, Toronto. METHODS: The CT scans of all patients undergoing LP shunting over a 17 year period were reviewed. The "absent cistern sign" and ventricular size were compared against the results of either an isotope shunt study or surgical findings performed within 2 days of the CT. RESULTS: There were 38 CT scans (27 patients) performed within 2 days of an isotope shunt study and 15 CT scans (14 patients) performed within 2 days of a surgical intervention. These results give the absent cistern sign a sensitivity of 75% and a specificity of 57% when compared to the shunt isotope findings and a sensitivity of 100% and a specificity of 50% when compared to the surgical findings. Over 30% of the CT scans showed ventriculomegaly in the presence of a functioning shunt and, conversely, nearly 45% of the CT scans had normal or small lateral ventricles in the presence of a malfunctioning shunt. CONCLUSIONS: The "absent cistern sign" appears to reliably rule out a completely blocked shunt, but is less reliable in detecting a normal or partially obstructed shunt. Ventricular size correlates poorly with LP shunt function.
    [Abstract] [Full Text] [Related] [New Search]