Use of ultrasound imaging software to differentiate venous and lymphatic edema in lower limbs

BACKGROUND: Lower limb edema has both systemic and local causes. Using software to differentiate the origin of edema in ultrasound images is an innovation. OBJECTIVE: To determine the parameters for using software to differentiate edema of venous and/or lymphatic origin in ultrasound images of the lower limbs. METHOD: This is a cross-sectional, quantitative, analytical study with non-probabilistic sampling by convenience. Data were collected by patient interview, physical examination, ultrasound examination, and analysis of software for tissue characterization in ultrasound image by means of quantification of echogenicity and Gray Scale Median (GSM). RESULTS: The sample comprised 42 lower limbs with venous edema, 35 with lymphatic edema, 14 with mixed edema, and 11 control limbs. The distributions of pixels in echogenicity intervals by group was as follows. In the venous edema group, 88.31% were distributed from hypoechogenic interval IV to echogenic interval III; in the lymphatic edema group 71.73% were from hypoechogenic interval II to echogenic interval I; in the mixed edema group 76.17% were from hypoechogenic interval III to echogenic interval II; and in the control group 84.87% were distributed from echogenic interval II to hyperechogenic interval I. Mean and standard deviation of GSM values showed statistical differences between groups. CONCLUSION: The CATUS software enabled differentiation of the type of lower limb edema, facilitating diagnosis of edema type and, consequently, choice of the best therapeutic option.