TABLE 3.
Preclinical MRI and DTI whole brain imaging studies
| Studies | Size | Group | Age | Modality | Results |
|---|---|---|---|---|---|
| Lapointe, Viamonte, Morriss, and Manolidis (2006) | 40 | SNHL | Pediatric | T1 and T2 | Some changes in T2 but eight had abnormalities from myelination delays to migrational anomalies |
| Trimble, Blaser, James, and Papsin (2007) | 92 | Preop CI | Pediatric | FLAIR | 32% abnormalities in TB; some subcortical signal intensities discrepancies |
| Roche et al. (2010) | 118 | ANSD | Pediatric | MR | 40% had brain abnormalities; 28% had CN deficiencies |
| CT | 16% had cochlear dysplasia | ||||
| Hong, Jurkowski, and Carvalho (2010) | 57 | Preop CI | Pediatric | MR | 18% with white matter abnormalities (two had postop delays in performance), no serious CNS diseases |
| Chilosi et al. (2010) | 80 | SNHL | Pediatric | MR | 48% with additional disabilities (cognitive, behavioral–emotional and motor). 37 signal abnormalities—brain malformations (46%) and white matter abnormalities (54%) |
| Chang et al. (2012) | 18 | Preop CI | Pediatric | DT | FA in Broca's, genu CC, auditory tract and MGN correlated with auditory scores after CI |
| Mackeith, Joy, Robinson, and Hajioff (2012) | 158 | Preop CI | Pediatric and adults | MR | Detected abnormalities (n = 27.9%, missed by CT in 6.3%) of which only 12.7% considered significant |
| CT | 6.3% only noncritical abnormalities in CT | ||||
| Moon et al. (2012) | 177 | Preop CI | Pediatric | MR | Children with no lesions (n = 150) performed better than those with lesions |
| Proctor, Gawne-Cain, Eyles, Mitchell, and Batty (2013) | 51 | Preop CI | Pediatric and adults | MR | Five adults and 16 children—whole brain abnormalities; 36 had at least one CI. Of 15 who did not have CI, eight positive findings in whole brain MRI |
| Jonas et al. (2012) | 162 | Preop CI | Pediatric | MR | 30% had abnormalities mostly white matter changes related to pre-existing medical conditions |
| Z. Y. Jiang, Odiase, Isaacson, Roland, and Kutz (2014) | 188 | Preop CI | Adult | MR | 9% had cochlear pathway and white matter abnormalities; in others, 65% had normal MRI scans |
| X.-Q. Xu, Wu, Hu, Su, and Shen (2015) | 157 | Preop CI | Pediatric | MR and CT | White matter changes most common but effect on CI minimal |
| Huang et al. (2015) | 24 | Preop CI | Pediatric | DT | Lesser FA in TB, SON, IC, MGB, AR and WMHG in 16 with CAP <6 |
| Park, Chung, Kwon, and Lee (2018) | 1 | Preop CI | Pediatric | DT | Less FA in WMHG, IFOF, UF, SLF and forceps major only in age <4 years |
| Feng et al. (2018) | 37 | Preop CI | Pediatric | MR | Auditory association and cognitive brain regions which are unaffected by auditory deprivation provide positive outcomes |
Abbreviations: ANSD, auditory neuropathy spectrum disorder; AR, acoustic radiation; CAP, category of auditory performance; CC, corpus callosum; CI, cochlear implant; CN, cochlear nerve; CNS, central nervous system; CT, computed tomography; DT, diffusion tensor; FA, fractional anisotropy; FLAIR, fluid-attenuated inversion recovery; IC, inferior colliculus; IFOF, inferior fronto-occiptal fasciculus; MGB, medial geniculate body; MGN, medial geniculate nucleus; MR, magnetic resonance; Preop, pre-operative; SLF, superior longitudinal fasciculus; SNHL, sensorineural hearing loss; SON, superior oliviary nucleus; T1/T2, MR-weighted image; TB, temporal bone; UF, uncinate fasciculus; WMHG, white matter Heschl's gyrus.