Diagnosis of small vestibular schwannomas using constructive interference steady state sequence.

OBJECTIVES/HYPOTHESIS: The objectives of this study were to evaluate the diagnostic accuracy of constructive interference steady state (CISS) sequencing compared to gadolinium-enhanced T1 (GdT1) magnetic resonance imaging (MRI) to screen for small vestibular schwannomas (VSs), and to assess the overall diagnostic confidence of neuroradiologists in their ability to accurately diagnose or rule out VSs using CISS imaging compared to a GdT1 MRI STUDY DESIGN: Retrospective chart review.

METHODS: Chart review from 2011 to 2015 was performed for VS/benign cerebellopontine angle tumors. Two blinded, board-certified neuroradiologists each independently reviewed the axial CISS sequence and answered a set of questions that determined their confidence in diagnosis of VS. Next, each neuroradiologist independently reviewed the corresponding GdT1 MRI sequence and completed the same questionnaire.

RESULTS: The majority of the lesions were in the lateral internal auditory canal, with eight intralabyrinthine tumors. The overall sensitivity of CISS for both readers was 93.5%. All tumor locations had high sensitivities except for the intralabyrinthine location (62.3%). Four of the eight total intralabyrinthine lesions were missed by at least one reader. Each reader was highly confident in diagnosing VSs with CISS, which approximated that of GdT1 MRI.

CONCLUSIONS: This study's results showed that CISS examinations for screening of small VS approximated that of GdT1. Neuroradiologists had high sensitivity, perfect specificity, and felt confident in ruling out a VS on CISS sequence while feeling extremely confident in diagnosing one on CISS. Intralabyrinthine lesions and lesions ≤3.0 mm are most at risk for not being detected on CISS examinations.

LEVEL OF EVIDENCE: 4 Laryngoscope, 128:2128-2132, 2018.