Magnetic Resonance Imaging at 1.5 Tesla With a Cochlear Implant Magnet in Place: Image Quality and Usability.
Otol Neurotol 2017;
37:1284-90. [PMID:
27525711 DOI:
10.1097/mao.0000000000001176]
[Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE
To study the quality and usability of magnetic resonance imaging (MRI) obtained with a cochlear implant magnet in situ.
STUDY DESIGN
Retrospective chart review.
SETTING
Tertiary care center.
PATIENTS
All patients who underwent brain MRI with a cochlear implant magnet in situ from 2007 to 2016.
INTERVENTION(S)
None.
MAIN OUTCOME MEASURE(S)
Grade of view of the ipsilateral internal auditory canal (IAC) and cerebellopontine angle (CPA).
RESULTS
Inclusion criteria were met by 765 image sequences in 57 MRI brain scans. For the ipsilateral IAC, significant predictors of a grade 1 (normal) view included: absence of fat saturation algorithm (p = 0.001), nonaxial plane of imaging (p = 0.01), and contrast administration (p = 0.001). For the ipsilateral CPA, significant predictors of a grade 1 view included: absence of fat saturation algorithm (p = 0.001), high-resolution images (p = 0.001), and nonaxial plane of imaging (p = 0.001). Overall, coronal T1 high-resolution images produced the highest percentage of grade 1 views (89%). Fat saturation also caused a secondary ring-shaped distortion artifact, which impaired the view of the contralateral CPA 52.7% of the time, and the contralateral IAC 42.8% of the time. MRI scans without any usable (grade 1) sequences had fewer overall sequences (N = 4.3) than scans with at least one usable sequence (N = 7.1, p = 0.001).
CONCLUSION
MRI image quality with a cochlear implant magnet in situ depends on several factors, which can be modified to maximize image quality in this unique patient population.
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