Evaluation of automated tool for two-dimensional fetal biometry.

OBJECTIVE: To evaluate whether an automated tool can recognize a structure of interest and measure fetal head circumference (HC), abdominal circumference (AC) and femur length (FL) on frozen two-dimensional ultrasound images. METHODS: Ultrasound examinations were performed in 100 singleton pregnancies between 20 and 40 weeks of gestation, ensuring an even distribution throughout gestational age. In each pregnancy, three standard biometric variables (HC, AC, FL) were measured each in three different images obtained for this purpose (i.e. nine independent image acquisitions). An algorithm (Philips Research) was used to detect the structure of interest and automatically place calipers for measurement. Caliper placement was assessed in two ways. First, subjective clinical assessment was performed to determine whether the caliper placement was correct, and caliper position was classified as 'acceptable for clinical use', 'minor adjustment required' or 'major adjustment required'. Second, the resulting automatic measurements were compared with manual measurements, taken in real time. Mean difference errors were calculated and expressed as percentages to correct for fetal growth with advancing gestation. RESULTS: After exclusion of one pregnancy due to missing images, a total of 891 images (297 for each biometric variable) from 99 pregnancies were analyzed. The algorithm failed to place calipers for the AC in nine images, whereas there were no failures in caliper placement for measurement of HC and FL. On subjective quality assessment of automatic caliper placement, in 475 (53.3%) images position of the calipers was judged to be clinically acceptable and did not require any adjustment, while in 317 (35.6%) and 90 images (10.1%) minor and major adjustments were required, respectively. The mean error between manual and automatic measurement of HC was -0.21 cm corresponding to a percentage error of -0.81% with 95% limits of agreement (LOA) between -3.73% and 2.12%. For AC and FL measurements, the mean error was, respectively, 0.72 cm (percentage error, 2.40%) with LOA between -9.48% and 14.27%, and 0.21 cm (percentage error, 3.76%) with LOA between -8.38% and 15.91%. CONCLUSIONS: The automated tool identified correctly the biometric variable of interest in 99% of frozen images. The resulting measurements had a high degree of accuracy and compared well with previously published manual-to-manual agreement. The measurements exhibited bias, with the automated tool underestimating biometry; this could be overcome by further improvements in the algorithm. Nevertheless, adjustable calipers for manual correction remains a requirement. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Three-dimensional imaging of solid breast tumors with ultrasound: preliminary data and analysis of its possible contribution to the understanding of the standard two-dimensional sonographic images.

Reconstructed three-dimensional sonographic images are presented from patients having different histological types of breast tumors. Scanning is manual and performed using two-dimensional annular array, sector transducers fitted on a mechanical arm, to provide spatial location. The three-dimensional data are displayed using two different modalities. Planar reformatted sections allow the visualization of planes reconstructed along any direction chosen by the operator. Of particular interest are the reconstructions obtained along equatorial planes of the tumors, i.e. planes parallel to the chest wall and, consequently, to the fibroglandular layer of the breast. Volume rendering is obtained using the shaded-surface visualization technique.Three-dimensional imaging provides new information and allows a better interpretation of the standard two-dimensional images. Planar reformatted sections confirm that ductal carcinomas present margin jagging on all views, including the equatorial section planes. Using the shaded-surface visualization technique, these tumors appear with a spiked outer surface. Thus, the most specific sonographic finding associated with ductal carcinomas may be that margin jagging extends over the entire periphery of the mass. On planar reformatted sections, benign tumors are surrounded by a continuous hyperechogenic rim, i.e. the rim is present irrespective of the section plane orientation. Medullary carcinomas are also surrounded by a hyperechogenic rim. However, a clearly distinctive feature of these lesions is found on planar reformatted sections: the rim is discontinuous on certain section planes. A mass can be considered benign only if its rim is continuous, i.e. if it is present all around the tumor.