Comparison of the low‐contrast detectability of two ultrasound systems using a grayscale phantom

Abstract

The purpose of the present study was to use a commercially available grayscale phantom to compare two ultrasound systems regarding their ability to reproduce clinically relevant low‐contrast objects at different sizes and depths, taking into account human observer variability and other methodological issues related to observer performance studies. One high‐end and one general ultrasound scanner from the same manufacturer using the same probe were included. The study was intended to simulate the clinical situation where small low‐contrast objects are embedded in relatively homogeneous organs. Images containing 4 and 6.4 mm objects of four different contrasts were acquired from the grayscale phantom at different depths. Six observers participated in a 4‐alternative forced‐choice study based on 960 images. Case sample and human observer variabilities were taken into account using bootstrapping. At four of sixteen depth/size/contrast combinations, the visual performance of the high‐end scanner was significantly higher. Thus, it was possible to use a grayscale phantom to discriminate between the two evaluated ultrasound systems in terms of their ability to reproduce clinically relevant low‐contrast objects. However, the number of images and number of observers were larger than those usually used for constancy control.PACS number(s): 87.57.C‐, 87.63.dh

Ultrasound grayscale image quality comparison between a 2D intracavitary transducer and a 3D intracavitary transducer used in 2D mode: A phantom study

“…First, contrast measurements do not take target size into calculation, while SNR does. Second, the SNR of spherical targets were comprehensively affected by the anechoic contrast as well as the spatial resolution performances . In addition, all the SNR results were above the visual detection threshold that the small differences in contrast might not be clinically important …”

Systematic optimization of ultrasound grayscale imaging presets and its application in abdominal scanning

“…Subtle changes to basic parameters from step 2 might still be necessary because of real‐time scanning of the better test objects. Frame rate was also checked to make sure that the new presets did not have a significantly lower frame rate, before they were established and saved. Image performance metrics confirmation of the new presets, which may include measurement of lesion signal noise ratio (SNR), 8–10 resolution integral, 11 or low‐contrast detectability 12 . This step is to ensure that preset changes would not inadvertently lower the system performance.…”

“…which may include measurement of lesion signal noise ratio (SNR), 8-10 resolution integral, 11 or low-contrast detectability. 12 This step is to ensure that preset changes would not inadvertently lower the system performance. Here, 10 image pairs were acquired from the 4-mm anechoic spherical targets (GAMMEX Model 408 spherical lesion phantom, GAMMEX Sun Nuclear, Middleton, WI) at 4-8 cm of depth and from corresponding background regions using both the original and new presets on system 1.…”

Viewdex 3.0—RECENT Development of a Software Application Facilitating Assessment of Image Quality and Observer Performance

“…The ViewDEX software can be downloaded free of charge from www.vgregion.se/sas/viewdex , and in the end of October 2020 ViewDEX had been downloaded from over 40 countries and had received over 230 citations in scientific publications. ViewDEX has for example been used for studies in conventional projection radiography ( 6 ) , tomosynthesis ( 7 ) , computed tomography (CT) ( 8 ) , mammography ( 9 ) , magnetic resonance imaging (MRI) ( 10 ) , nuclear medicine imaging ( 11 ) , interventional imaging ( 12 ) and ultrasound ( 13 ) .…”