Hyoid Bone Development: An Assessment Of Optimal CT Scanner Parameters and Three‐Dimensional Volume Rendering Techniques

Abstract

The hyoid bone anchors and supports the vocal tract. Its complex shape is best studied in three dimensions, but it is difficult to capture on computed tomography (CT) images and three-dimensional volume renderings. The goal of this study was to determine the optimal CT scanning and rendering parameters to accurately measure the growth and developmental anatomy of the hyoid and to determine whether it is feasible and necessary to use these parameters in the measurement of hyoids from in vivo CT scans. Direct linear and volumetric measurements of skeletonized hyoid bone specimens were compared to corresponding CT images to determine the most accurate scanning parameters and three-dimensional rendering techniques. A pilot study was undertaken using in vivo scans from a retrospective CT database to determine feasibility of quantifying hyoid growth. Scanning parameters and rendering technique affected accuracy of measurements. Most linear CT measurements were within 10% of direct measurements; however, volume was overestimated when CT scans were acquired with a slice thickness greater than 1.25 mm. Slice-by-slice thresholding of hyoid images decreased volume overestimation. The pilot study revealed that the linear measurements tested correlate with age. A fine-tuned rendering approach applied to small slice thickness CT scans produces the most accurate measurements of hyoid bones. However, linear measurements can be accurately assessed from in vivo CT scans at a larger slice thickness. Such findings imply that investigation into the growth and development of the hyoid bone, and the vocal tract as a whole, can now be performed using these techniques.

Hyoid bone fusion and bone density across the lifespan: prediction of age and sex

“…Additional CT scans from both typically and atypically developing individuals, such as those with Down syndrome or cerebral palsy, would permit us to better understand the nature of hyoid bone fusion across the lifespan as well as the overall trends of hyoid bone form and function during growth and development. Cotter et al [ 4 ] found that ex vivo hyoid bones taken from cadavers can be suitably compared to 3D renderings of in vivo hyoid bones created from CT scans. Additional measurements, including linear, angular and volume, of the hyoid bone from CT scans would permit us to test models that incorporate dimensions of the hyoid bone and bone density for understanding developmental trends and further refining sex and age estimation.…”

“…Intensity in Hounsfield units (HU), commonly used to measure bone density, was then calculated from the outlined region defined by the 3D model generated using the Region of Interest tool (ROI) within Analyze 11.0 ® . See Cotter et al [ 4 ] for additional detail on modeling methods. Lee et al [ 22 ], Majumdar and Leslie [ 23 ], Schreiber et al [ 24 ], and Lee et al [ 25 ] all found that intensity in Hounsfield units calculated from CT scans is a suitable estimation for bone mineral density as calculated by dual-energy X-ray absorptiometry (DXA), which remains the gold standard for bone density measurement.…”

“…In infancy, the hyoid bone lies just anteriorly to the second and third cervical vertebrae, and eventually lowers to the level of the fourth and fifth cervical vertebrae in adults [ 3 ]. Hyoid bone descent occurs concurrently with descent of functionally related structures, namely the larynx and epiglottis [ 4 ]. The only bone in the body that is free-floating, the hyoid bone maintains attachment with the mandible, tongue, styloid processes, thyroid cartilage, cricoid cartilage, clavicles, and sternum by ligament and muscle attachments [ 1 ].…”

“…The hyoid bone develops from the branchial arches and the midline mesenchymal condensation (MMC) between the second and third branchial arch cartilages. The hyoid body comes directly from the MMC, the lesser cornua and the stylohyoid ligament derive from the second branchial cartilages, and the greater cornua derive from the third branchial cartilages [ 4 , 5 ]. The hyoid body and the two greater cornua contain pairs of ossification centers [ 5 ].…”

Developmental morphology of the cervical vertebrae and the emergence of sexual dimorphism in size and shape: A computed tomography study

“…The Bone and Soft algorithms were included if the Standard algorithm was not available to ensure a balance in age and sex distribution in this study. As for slice thickness, both Whyms et al (2013) and Cotter et al (2015) determined less than or equal to 2.5 mm thickness to be adequate for the reliable assessment of linear measurement of growth and development for the mandible and the hyoid bone, respectively. For additional detail, see Miller et al (2019).…”