Incidental Finding Prevalences in 3-Tesla Brain and Spine MRI of Military Pilot Applicants

INTRODUCTION: Incidental findings in brain and spine MRI are common. In aerospace medicine, pilot selection may be affected by improved sensitivity of modern MRI devices. We investigated the occurrence of medically unfit rates caused by incidental findings in military pilot applicants using a 3-Tesla scanner as compared to the outcomes of a lower field strength 1-Tesla device based on similar screening protocols.METHODS: A total of 3315 military pilot applicants were assessed by a standardized German Air Force Imaging Screening Protocol and retrospectively subdivided into two cohorts, one of which was assessed by 1-Tesla MRI (2012-2015; N 1782), while in the second cohort (2016-2019; N 1808), a 3-Tesla MRI was used. Cohorts were statistically analyzed relating to three entities of incidental findings: 1) intervertebral disc displacements, 2) intracerebral vessel malformations, and 3) other abnormal findings in the brain.RESULTS: Pooled prevalences of incidental findings in medically unfit applicants significantly increased by use of 3-Tesla MRI as compared to lower resolution 1-Tesla MRI. Regarding the spine, prevalences more than doubled (1.46 vs. 4.99%; P < 0.05) for intervertebral disc displacements. Similarly, prevalences of cerebral vessel malformations as well as other abnormal CNS incidental findings considerably increased by use of 3-Tesla MRI (0.28 vs. 1.67%; P < 0.05, and 5.12 vs. 9.80%; P < 0.05). Effect sizes and correlations were substantial in all conditions analyzed (Cohens d > 0.8; Pearsons r > 0.75).CONCLUSIONS: Our data suggest a strong dependency of incidental cerebrospinal findings on image resolution and sensitivity of MRI devices used for screening, which is enhanced by refined imaging protocols and followed by increased medical unfit rates in prospective aviators. Adjusted strategies in the assessment of such lesions are needed to redefine their natural history and physiological impact, and to optimize screening protocols for future pilot selection.Snksen S-E, Khn SR, Nobl H-J, Knopf H, Ehling J, Jakobs FM, Frischmuth J, Weber F.