Nozomu Matsumoto
Nozomu Matsumoto, M.D., Ph.D. is the professor and chairperson of Department of Otorhinolaryngology, Faculty of Medicine, Fukuoka University. He graduated from Kyushu University for M.D. (1997) and then finished his Ph.D. course in Graduate School of Medical Sciences, Kyushu University (2003). He was then trained as a postdoctoral scientist in House Ear Institute in Los Angeles, USA (2003-2005). He then came back to Kyushu University and became a Japanese board-certified otolaryngologist in 2006. He is subspecialized in otology and his clinical duty is to treat patients suffering from ear diseases. He is in charge of cochlear implant program of Fukuoka University Hospital. He also holds a research project of computer-aided surgery. His team has developed and patented noninvasive methods for image-guided otological surgery, and has performed over 70 image-guided temporal bone surgeries.
Session
Cochlear implants (CIs) were initially incompatible with MRI. Recently, MRI-conditional implants that permit scanning without magnet removal or compressive bandaging have been introduced. However, MRI in CI recipients is often degraded by device-related artifacts, which may limit its clinical utility. In this study, we evaluated head MRI findings in some patients who underwent cochlear implantation at our institution and analyzed differences in artifact size across imaging modalities and sequences, together with their clinical applicability. Without magnet removal, diffusion-weighted imaging (DWI) and T2 star-weighted imaging produced larger artifacts and yielded limited diagnostic value. In contrast, T1-weighted, T2-weighted, fluid-attenuated inversion recovery (FLAIR), and heavily T2-weighted sequences allowed assessment of the contralateral side and central regions of the head, although visualization on the implanted side remained restricted. Image characteristics varied depending on both MRI modality and sequence, indicating that MRI protocols should be carefully selected according to clinical purpose and feasibility. Awareness of sequence-specific imaging characteristics is essential, and the expected diagnostic value should be considered in advance when determining MRI indications in CI patients.