Characterization of CT Hounsfield Units for 3D acquisition trajectories on a dedicated breast CT system

Abstract

Hounsfield Units (HU) are used clinically in differentiating tissue types in a reconstructed CT image, and therefore the HU accuracy of a system is important, especially when using multiple sources, novel detector and non-traditional trajectories. Dedicated clinical breast CT (BCT) systems therefore should be similarly evaluated. In this study, uniform cylindrical phantoms filled with various uniform density fluids were used to characterize differences in HU values between simple circular and complex 3D (saddle) orbits. Based on ACR recommendations, the HU accuracy, center-to-edge variability within a slice, and overall variability within the reconstructed volume were characterized for simple and complex acquisitions possible on a single versatile BCT system. Results illustrate the statistically significantly better performance of the saddle orbit, especially close to the chest and nipple regions of what would clinically be a pendant breast volume. The incomplete cone beam acquisition of a simple circular orbit causes shading artifacts near the nipple, due to insufficient sampling, rendering a major portion of the scanned phantom unusable, whereas the saddle orbit performs exceptionally well and provides a tighter distribution of HU values throughout the reconstructed volumes. This study further establishes the advantages of using 3D acquisition trajectories for breast CT as well as other applications by demonstrating the robustness of HU values throughout large reconstructed volumes.

Development of a dynamic imaging method for gravitropism in pea sprouts using clinical magnetic resonance imaging system

“…Furthermore, an MRI system is superior because of its ability to sensitively identify differences in internal information. Since the X-ray transmittance is reflected in an image in CT (Shah et al 2018), the change in the pixel value of a soft tissue image is small. However, in MRI, the distinction in a composition is evident because characteristic values such as proton density and relaxation time (T1 and T2) are reflected in the pixel value.…”

Applications of Computational Methods in Biomedical Breast Cancer Imaging Diagnostics: A Review

“…Dedicated breast computed tomography (DBCT) is a recently used and fastest-growing imaging technique that allows for true isotropic and provides three-dimensional (3D) information which can be reconstructed or rebuilt into several imaging planes. Although DBCT is comparable to breast magnetic resonance imaging (MRI), the process involved can be carried out without breast compression, and is not limited by breast implants or the density of the breast [ 41 , 42 , 43 ]. The radiation dose in this type of imaging technique is similar to that of a conventional two-view mammogram [ 42 ].…”

“…The invention, improvement, and development of DBCT with dedicated scanners with novel technology has been documented in the literature by Sarno et al [ 45 ]. Studies further reported the development of low radiation dose scanners with improved spatial resolution and rapid image acquisition times, which is aimed at addressing the issue of imaging dense breasts and painful breast compression [ 41 , 42 , 43 ].…”

“…Recently, Shah et al [ 43 ] investigated the characterization of computed tomography (CT). Hounsfield units were used in clinical settings for the purpose of tissue differentiation in a reconstructed CT image in 3D acquisition trajectories on a DBCT system.…”