title: Optimization of parameter settings in cine-MR imaging for diagnosis of swallowing.
abstract: Videofluorography is frequently used to evaluate swallowing and is considered the "gold standard" among imaging modalities. This modality, however, has several disadvantages, including radiation exposure and limitations in the detection of soft tissues. Conversely, magnetic resonance imaging (MRI) offers excellent contrast resolution in soft tissue without radiation exposure. A major drawback of MRI in evaluating swallowing, however, is that temporal resolution is poor. The aim of this study was to investigate a new cine-MRI modality. Imaging parameters were optimized and the efficacy of this new technique is discussed. Three techniques for speeding up MRI were combined: true fast imaging with steady state precession, generalized auto-calibrating partially parallel acquisition, and key-hole imaging. The effects of the receiver coils used, receiving bandwidth, slice thickness, and flip angle on each image were determined. The optimal imaging parameters obtained comprised a reduction factor of 2, receiving bandwidth of 1,000 Hz/pixel (repetition time of 151.7 milliseconds and echo time of 1.4 milliseconds), flip angle of 50°, and slice thickness of 6 mm. Neck and spine coils were used. Under these conditions, the new cine-MR imaging technique investigated showed a temporal resolution of 0.1 sec/slice (10 frames/sec). Even with optimized parameter settings, this technique did not allow a true temporal resolution of 30 frames/sec by a large margin. Motion artifacts persisted. Further study is needed on how to speed up this technique.
authors.affiliation: Department of Dysphagia Rehabilitation and Community Dental Care, Tokyo Dental College.
authors.forename: Mai
authors.initials: M
authors.lastname: Ohkubo
authors.forename: Takuo
authors.initials: T
authors.lastname: Higaki
authors.forename: Keiichi
authors.initials: K
authors.lastname: Nishikawa
authors.forename: Mika
authors.initials: M
authors.lastname: Otonari-Yamamoto
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Sugiyama
authors.forename: Ryo
authors.initials: R
authors.lastname: Ishida
authors.forename: Mamoru
authors.initials: M
authors.lastname: Wako
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Sano
mesh_terms: D000328:Adult; D016477:Artifacts; D003679:Deglutition / Q000502:physiology*; D004947:Esophagus / Q000502:physiology; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000295:instrumentation / Q000379:methods*; D019028:Magnetic Resonance Imaging, Cine / Q000295:instrumentation / Q000379:methods*; D009960:Oropharynx / Q000502:physiology; D021362:Palate, Hard / Q000502:physiology; D010614:Pharynx / Q000502:physiology; D013997:Time Factors; D014059:Tongue / Q000502:physiology