TABLE 1

Input Probabilities

ParameterBase Case AnalysisRange for Sensitivity Analysis
Pretest probability of shunt failure230%10%–50%
Sensitivity of CT323766%53%–88%
Specificity of CT323787%76%–96%
Sensitivity of fsMRI32,36,3858%51%–78%
Specificity of fsMRI32,36,3893%89%–98%
Sensitivity of ONSD161975%61%–83%
Specificity of ONSD161932%22%–38%
Sensitivity of SS3335,3719%4%–30%
Specificity of SS3335,3795%91%–98%
Probability of death and/or missed diagnosisa0.1% (1:1000)0.01%–0.2%
Probability of radiation-induced malignancy9,11,21,31,390.22%0.07%–0.6%
Patient metrics
 No. of cranial CTs for per patient-year2,911–10
 Age920–18
 Life expectancy247860–82
 Average annual mortality rate from cancer215%1%–10%
 Length of headache/delayed diagnosis, wka11–4
 Postoperative recovery time, wka42–8
 Discount rate403%1%–5%
  • a Author estimate.