Objective: We compared cost-effectiveness of cranial computed tomography (CT), fast sequence magnetic resonance imaging (fsMRI), and ultra sonographic measurement of optic nerve sheath diameter, for suspected acute shunt failure, from a healthcare organizational perspective. Methods: We modeled 4 diagnostic imaging strategies: 1) CT scan; 2) fsMRI; 3) screening optic nerve sheath diameter (ONSD) using point of care ultrasound (POCUS) first, combined with CT (POCUS-CT); and 4) screening ONSD using POCUS first, combined with fsMRI (POCUS-fsMRI). An initial plain radiography (shunt series) screen was performed on all patients. Short and long-term costs of radiation- induced cancer were assessed with a Markov model. Effectiveness was measured as quality adjusted life years (QALYs). Utilities and inputs for clinical variables were obtained from published literature. Sensitivity analyses were performed to evaluate the effects of parameter uncertainty. Results: At a prior probability of shunt failure of 30%, a screening POCUS in patients with a normal shunt series, was the most cost-effective. For children with abnormal shunt series or ONSD measurement, fsMRI was the preferred option over CT. Performing fsMRI on all patients would cost $269,770 to gain 1 additional quality-adjusted life-year, compared with POCUS. An imaging pathway that involves CT alone was dominated by ONSD and fsMRI as it was more expensive and less effective. Conclusions: In children with low pretest probability of cranial shunt failure, an ultrasonographic measurement of ONSD is the preferred initial screening test. In the young child with suspected shunt failure, fsMRI is the more cost-effective definitive imaging test when compared with cranial CT.

Figure 1

Decision analysis model assessing 3 imaging strategies for a hypothetical population of patients with suspected cranial shunt malfunction

Figure 1

Decision analysis model assessing 3 imaging strategies for a hypothetical population of patients with suspected cranial shunt malfunction

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Figure 2

Cost Effectiveness Acceptability Curve at various Willingness-to-Pay Thresholds

Figure 2

Cost Effectiveness Acceptability Curve at various Willingness-to-Pay Thresholds

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