Should we be moving to a national standardized non-gadolinium MR imaging protocol for the surveillance of vestibular schwannomas?

Objectives: To examine whether the model of Getting It Right First Time (GIRFT) could be relevant to the surveillance of non-operated vestibular schwannomas (vs) by testing the following hypotheses: (1) in the UK there is a great variation in the imaging protocol for the follow-up of vs; (2) high-resolution, T-2 weighted MRI (HRT2W-MRI) has an equivalent accuracy to gadolinium-enhanced T-1 weighted MRI (Gd-MRI) in the assessment of vs size and; (3) imaging with HRT2W-MRI rather than Gd-MRI could offer financial savings. Methods: Two neuroradiologists independently performed measurements of 50 vs imaged with HRT2W-MRI and Gd-MRI. Differences in mean tumour measurements between HRT2W-MRI and Gd-MRI were determined, as were intra- and interobserver concordance. Level of agreement was measured using Bland-Altman plots. Consultant neuroradiologists within 30 adult neurosurgical units in the UK were contacted via email and asked to provide the MRI protocol used for the surveillance of non-operated vs in their institution. The financial difference between scanning with HRT2W-MRI and Gd-MRI was determined within Leeds Teaching Hospitals NHS Trust. Results: There was no statistically significant difference in the mean diameter of vs size, measured on HRT2W-MRI and Gd-MRI (p = 0.28 & p = 0.74 for observers 1 and 2 respectively). Inter- and intraobserver concordance were excellent (Interclass correlation coefficient = 0.99, Interclass correlation coefficient >= 0.98 respectively). Differences between the two sequences were within limits of agreement. 26 of 30 UK neuroscience centres (87 % response rate) provided imaging protocols. 16 of the 26 (62%) centres use Gd-MRI for the surveillance of vs. HRT2-MRI is (sic)36.91 cheaper per patient than Gd-MRI. Conclusion: Variation exits across UK centres in the imaging surveillance of non-operated vs. HRT2W-MRI and Gd-MRI have equivalent accuracy when measuring vs. Imaging with HRT2W-MRI rather than Gd-MRI offers potential financial savings. Advances in knowledge: This study highlights the potential health and economic benefits of a national standardized imaging protocol for the surveillance of non-operated vs.