Semiautomatic contour detection of breast lesions in ultrasonic images with morphological operators and average radial derivative function

AbstractThis work presents a computerized lesion segmentation technique on breast ultrasound images. There were applied known techniques such as morphological filtering, Watershed transformation and average radial derivative function. To evaluate the performance of the proposed method, two protocols were established. For the first, the resulting segmentation contours were compared with those of 24 gold standard simulated ultrasound-like images, and, for second, with 36 breast US images manually delineated by two senior radiologists. Further, two evaluation parameters were used: the percentage of coincidence (CP) and the proportional distance (PD). The former indicates the similarity between contours, while the latter express the dissimilarity. The accuracy of the proposed method was evaluated by considering images with CP>80% and PD<10% as adequately delineated. It was higher than 80% for real images and higher than 88% for simulated images

Ultrasound method applied to characterize healthy femoral diaphysis of Wistar rats in vivo

A simple experimental protocol applying a quantitative ultrasound (QUS) pulse-echo technique was used to measure the acoustic parameters of healthy femoral diaphyses of Wistar rats in vivo. Five quantitative parameters [apparent integrated backscatter (AIB), frequency slope of apparent backscatter (FSAB), time slope of apparent backscatter (TSAB), integrated reflection coefficient (IRC), and frequency slope of integrated reflection (FSIR)] were calculated using the echoes from cortical and trabecular bone in the femurs of 14 Wistar rats. Signal acquisition was performed three times in each rat, with the ultrasound signal acquired along the femur's central region from three positions 1 mm apart from each other. The parameters estimated for the three positions were averaged to represent the femur diaphysis. The results showed that AIB, FSAB, TSAB, and IRC values were statistically similar, but the FSIR values from Experiments 1 and 3 were different. Furthermore, Pearson's correlation coefficient showed, in general, strong correlations among the parameters. The proposed protocol and calculated parameters demonstrated the potential to characterize the femur diaphysis of rats in vivo. The results are relevant because rats have a bone structure very similar to humans, and thus are an important step toward preclinical trials and subsequent application of QUS in humans

Characterization of cutaneous cell carcinomas by ultrasound biomicroscopy

AbstractThe potential of ultrasound biomicroscopy (UBM) images to evidence the alterations occurring in skin tissues affected by cutaneous carcinomas was studied. The histological patterns associated to these carcinomas can vary considerably between patients, involving diverse atypical tissue constituents which should be identified in UBM images, considering the perspective of applying this technique as a diagnostic tool. The study was conducted using in vitro fresh human tissue samples, obtained from biopsied volunteer patients. The UBM images were generated as in the conventional B-mode, and acquired with an experimental system working in a fundamental frequency of 45 MHz. Distinct tissues constituents, normal or pathologic, were identified in the UBM images by variations in the image brightness level, and could be observed in most of the studied cases. Moreover, the brightness characteristics associated to each tissue constituent seem to repeat along the different studied samples. Although the differentiation between the diverse structures was possible by a qualitative analysis, additional quantitative techniques (related to tissue acoustic, statistical and spectral properties) are been implemented, to improve the UBM diagnostic capability