3-T imaging of the cochlear nerve and labyrinth in cochlear-implant candidates: 3D fast recovery fast spin-echo versus 3D constructive interference in the steady state techniques.
OBJECTIVE
High-resolution imaging of the internal auditory canal and labyrinth at 1.5 T is often performed by using three-dimensional (3D) fast spin-echo or T2* techniques. We evaluated both techniques at 3 T in the preoperative assessment of patients being considered for cochlear implants.


METHODS
Sagittal 3D fast recovery fast spin-echo (FRFSE) and 3D constructive interference in the steady state (CISS) images were acquired in eight patients at 3.0 T by using dual surface coils. Contrast-to-noise ratios (CNRs) for the intracanalicular nerve and CSF were measured in the internal auditory canal. Two neuroradiologists reviewed the images to determine whether the techniques provided images of diagnostic quality.


RESULTS
CNRs for 3D CISS were twice those obtained with 3D FRFSE. Both techniques provided images of diagnostic quality, though spurious signal intensity loss at the apex of the superior semicircular canals was encountered on 3D FRFSE images in four of eight patients.


CONCLUSIONS
Both 3D FRFSE and 3D CISS provide high-resolution images of the internal auditory canal and labyrinth at 3.0 T. We predict that the superior CNRs obtained with 3D CISS will prove advantageous as we move to smaller fields of view at higher field strength.
Lane
John I
JI
Department of Radiology, Mayo Clinic, Rochester, MN, USA.
Ward
Heidi
H
Witte
Robert J
RJ
Bernstein
Matt A
MA
Driscoll
Colin L W
CL
D016477:Artifacts; D003051:Cochlea / Q000033:anatomy & histology* / Q000601:surgery; D019929:Cochlear Implantation; D003056:Cochlear Nerve / Q000033:anatomy & histology* / Q000601:surgery; D003638:Deafness / Q000534:rehabilitation; D007758:Ear, Inner / Q000033:anatomy & histology* / Q000601:surgery; D004711:Endolymphatic Duct / Q000033:anatomy & histology; D005154:Facial Nerve / Q000033:anatomy & histology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging; D012665:Semicircular Canals / Q000033:anatomy & histology / Q000473:pathology; D012680:Sensitivity and Specificity; D013673:Technology Assessment, Biomedical; D014584:User-Computer Interface; D014725:Vestibular Nerve / Q000033:anatomy & histology