MRI surveillance of vestibular schwannomas without contrast enhancement: Clinical and economic evaluation

Abstract

Objectives: To determine if high-resolution T2-weighted (HRT2) magnetic resonance imaging (MRI) is a comparably accurate and economical alternative to the gold standard of contrast-enhanced T1-weighted (T1C) MRI for surveillance of know vestibular schwannomas (VSs).

Study design: Retrospective case-control analysis, systematic review, and economic evaluation.

Methods: Vestibular schwannoma size in anteroposterior, mediolateral, and superoinferior axes were measured by two neuroradiologists, both blinded to previous measurements, for 50 randomized patients with T1C and HRT2 on two separate occasions. Measurements were assessed by Pearson product-moment correlation coefficients, and differences were analyzed by Student t test. Once the data were analyzed, appropriate economic evaluation was performed utilizing institutional-, federal-, and literature-based estimates of cost and incidence/prevalence.

Results: Pearson correlations (r) between T1C and HRT2 were 0.991 and 0.973 for radiologists 1 and 2, respectively, with no statistically significant differences (P ≤ 0.05) between imaging techniques. Intraobserver and interobserver reliability estimates (κ) were 0.88 to 1 for both T1C and HRT2, indicating very high reliability. Cost-minimization analysis demonstrated cost and charge differences of $148.02 and $1,284 per patient per scan, respectively. This represents an overall cost and charge savings for this 50-patient cohort of $7,401 and $64,200, respectively.

Conclusion: HRT2 imaging is a highly reliable and lower-cost alternative to T1C for follow-up surveillance scans in patients with VS.

Level of evidence: 2C. Laryngoscope, 128:202-209, 2018.

Keywords: MRI; Vestibular schwannoma; contrast; health economics; observation.