Dataset Information

Assessment of velopharyngeal function with dual-planar high-resolution real-time spiral dynamic MRI.

ABSTRACT: PURPOSE:To develop a real-time dynamic MRI method for comprehensive evaluation of velum movement during speech. METHODS:Dynamic MRI has been used to study velopharyngeal insufficiency (VPI) by imaging the movement of the velum during speech, because it can provide good anatomic details with no exposed radiation. To be able to comprehensively evaluate dynamic velum movement, a real-time spiral non-balanced SSFP sequence was developed with simultaneous dual-planar coverage and improved spatial and temporal resolution using a combination of parallel imaging and spatial and temporal compressed sensing to achieve 6?×?acceleration. New off-resonance correction and post-processing methods were also developed to reduce blurring and slice crosstalk. RESULTS:The method demonstrated good image quality for visualizing dynamic velum movement with reduced blurring and improved image homogeneity. Spatial resolution of 1.2*1.2?mm2 with 150?mm FOV and temporal resolution of 20 frames-per-second with simultaneous dual-planar coverage was achieved. CONCLUSIONS:This work describes a new technique for studying speech disorders using dual-planar accelerated spiral dynamic MRI.

SUBMITTER: Feng X

PROVIDER: S-EPMC6097923 | biostudies-literature | 2018 Oct

REPOSITORIES: biostudies-literature

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Assessment of velopharyngeal function with dual-planar high-resolution real-time spiral dynamic MRI.

Feng Xue X Blemker Silvia S SS Inouye Josh J Pelland Catherine M CM Zhao Li L Meyer Craig H CH

Magnetic resonance in medicine 20180305 4

<h4>Purpose</h4>To develop a real-time dynamic MRI method for comprehensive evaluation of velum movement during speech.<h4>Methods</h4>Dynamic MRI has been used to study velopharyngeal insufficiency (VPI) by imaging the movement of the velum during speech, because it can provide good anatomic details with no exposed radiation. To be able to comprehensively evaluate dynamic velum movement, a real-time spiral non-balanced SSFP sequence was developed with simultaneous dual-planar coverage and impro ...[more]

PMID: 29508458

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Project description:BackgroundReal-time cardiovascular magnetic resonance (CMR) assessment of ventricular volumes and function enables data acquisition during free-breathing. The requirement for high spatiotemporal resolution in children necessitates the use of highly accelerated imaging techniques.MethodsA novel real-time balanced steady state free precession (bSSFP) spiral sequence reconstructed using Compressed Sensing (CS) was prospectively validated against the breath-hold clinical standard for assessment of ventricular volumes in 60 children with congenital heart disease. Qualitative image scoring, quantitative image quality, as well as evaluation of biventricular volumes was performed. Standard BH and real-time measures were compared using the paired t-test and agreement for volumetric measures were evaluated using Bland Altman analysis.ResultsAcquisition time for the entire short axis stack (~?13 slices) using the spiral real-time technique was ~?20 s, compared to ~?348 s for the standard breath hold technique. Qualitative scores reflected more residual aliasing artefact (p?<?0.001) and lower edge definition (p?<?0.001) in spiral real-time images than standard breath hold images, with lower quantitative edge sharpness and estimates of image contrast (p?<?0.001). There was a small but statistically significant (p?<?0.05) overestimation of left ventricular (LV) end-systolic volume (1.0?±?3.5 mL), and underestimation of LV end-diastolic volume (-?1.7?±?4.6 mL), LV stroke volume (-?2.6?±?4.8 mL) and LV ejection fraction (-?1.5?±?3.0%) using the real-time technique. We also observed a small underestimation of right ventricular stroke volume (-?1.8?±?4.9 mL) and ejection fraction (-?1.4?±?3.7%) using the real-time imaging technique. No difference in inter-observer or intra-observer variability were observed between the BH and real-time sequences.ConclusionsReal-time bSSFP imaging using spiral trajectories combined with a compressed sensing reconstruction showed good agreement for quantification of biventricular metrics in children with heart disease, despite slightly lower image quality. This technique holds the potential for free breathing data acquisition, with significantly shorter scan times in children.

Project description:Dynamic imaging of the vocal tract using real-time MRI has been an active and growing area of research, having demonstrated great potential to become routinely performed in the clinical evaluation of speech and swallowing disorders. Although many technical advances have been made in regards to acquisition and reconstruction methodologies, there is still no consensus in best practice protocols. This study aims to compare Cartesian and non-Cartesian real-time MRI sequences, regarding image quality and temporal resolution trade-off, for dynamic speech imaging. Five subjects were imaged at 1.5T, while performing normal phonation, in order to assess velar motion and velopharyngeal closure. Data was acquired using both Cartesian and non-Cartesian (spiral and radial) real-time sequences at five different spatial-temporal resolution sets, between 10 fps (1.7×1.7×10 mm3) and 25 fps (1.5×1.5×10 mm3). Only standard scanning resources provided by the MRI scanner manufacturer were used to ensure easy applicability to clinical evaluation and reproducibility. Data sets were evaluated by comparing measurements of the velar structure, dynamic contrast-to-noise ratio and image quality visual scoring. Results showed that for all proposed sequences, FLASH spiral acquisitions provided higher contrast-to-noise ratio, up to a 170.34% increase at 20 fps, than equivalent bSSFP Cartesian acquisitions for the same spatial-temporal resolution. At higher frame rates (22 and 25 fps), spiral protocols were optimal and provided higher CNR and visual scoring than equivalent radial protocols. Comparison of dynamic imaging at 10 and 22 fps for radial and spiral acquisitions revealed no significant difference in CNR performance, thus indicating that temporal resolution can be doubled without compromising spatial resolution (1.9×1.9 mm2) or CNR. In summary, this study suggests that the use of FLASH spiral protocols should be preferred over bSSFP Cartesian for the dynamic imaging of velopharyngeal closure, as it allows for an improvement in CNR and overall image quality without compromising spatial-temporal resolution.

Dataset Information

Assessment of velopharyngeal function with dual-planar high-resolution real-time spiral dynamic MRI.

Publications

Assessment of velopharyngeal function with dual-planar high-resolution real-time spiral dynamic MRI.

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