Imaging Breast Microcalcifications Using Dark-Field Signal in Propagation-Based Phase-Contrast Tomography.

Breast microcalcifications are an important primary radiological indicator of breast cancer. However, microcalcification classification and diagnosis may be still challenging for radiologists due to limitations of the standard 2D mammography technique, including spatial and contrast resolution. In this study, we propose an approach to improve the detection of microcalcifications in propagation-based phase-contrast X-ray computed tomography of breast tissues. Five fresh mastectomies containing microcalcifications were scanned at different X-ray energies and radiation doses using synchrotron radiation. Both bright-field (i.e. conventional phase-retrieved images) and dark-field images were extracted from the same data sets using different image processing methods. A quantitative analysis was performed in terms of visibility and contrast-to-noise ratio of microcalcifications. The results show that while the signal-to-noise and the contrast-to-noise ratios are lower, the visibility of the microcalcifications is more than two times higher in the dark-field images compared to the bright-field images. Dark-field images have also provided more accurate information about the size and shape of the microcalcifications.

Propagation-based x-ray phase-contrast tomography of mastectomy samples using synchrotron radiation.

PURPOSE: Propagation-based phase-contrast computed tomography (PB-CT) is a method for three-dimensional x-ray imaging that utilizes refraction, as well as absorption, of x rays in the tissues to increase the signal-to-noise ratio (SNR) in the resultant images, in comparison with equivalent conventional absorption-only x-ray tomography (CT). Importantly, the higher SNR is achieved without sacrificing spatial resolution or increasing the radiation dose delivered to the imaged tissues. The present work has been carried out in the context of the current development of a breast CT imaging facility at the Australian Synchrotron. METHODS: Seven unfixed complete mastectomy samples with and without breast cancer lesions have been imaged using absorption-only CT and PB-CT techniques under controlled experimental conditions. The radiation doses delivered to the mastectomy samples during the scans were comparable to those approved for mammographic screening. Physical characteristics of the reconstructed images, such as spatial resolution and SNR, have been measured and compared with the results of the radiological quality assessment of the complete absorption CT and PB-CT image stacks. RESULTS: Despite the presence of some image artefacts, the PB-CT images have outperformed comparable absorption CT images collected at the same radiation dose, in terms of both the measured objective image characteristics and the radiological image scores. The outcomes of these experiments are shown to be consistent with predictions of the theory of PB-CT imaging and previous reported experimental studies of this imaging modality. CONCLUSIONS: The results presented in this paper demonstrate that PB-CT holds a high potential for improving on the quality and diagnostic value of images obtained using existing medical x-ray technologies, such as mammography and digital breast tomosynthesis (DBT). If implemented at suitable synchrotron imaging facilities, PB-CT can be used to complement existing imaging modalities, leading to more accurate breast cancer diagnosis.

[Psychomotor development in children born with anoxia--perinatal risk factors]. / Psihomotorni razvoj dece rodene u anoksiji--perinatalni faktori rizika.

In 1989 a control of psychomotor development was conducted in 318 children born with the Apgar score of 7 and less. The children controlled were of the age of 3 months to 6.5 years old. Clinical examination and the testing of children of up to the age of one year according to Brunet Lezin have shown a decrease in the number of points of nine children (4.05%). The finding points to a deviation in psychomotor development of a mild degree. Out of 80 preschool children, 8% of them had clinically evident signs of a possible cortical lesion, which were discreet and regarded the visuomotor, in other words visuoconstructive functions.

[Uterine hemorrhage in newborn infants]. / Uterino krvavljenje u novorodene dece.

A follow-up was conducted on uterine haemorrhage in all female newborn infants at the Department of Gynaecology and Obstetrics in Novi Sad, in the period from 1 January to 31 December 1979. Of the total of 2477 newborn female infants, 2241 (90.47%) were at-term infants of which 85 (3.79%) had uterine haemorrhage, 126 (5.09%) premature infants of which 1 (0.793) had uterine haemorrhage and 110 (4.443) postmature infants of which 10 (9.09%) had uterine haemorrhage. General frequency of uterine haemorrhage was 3.87%.