Breast ultrasound (US) is being performed with increasing frequency. Starting from the third decade of life, many symptomatic or asymptomatic women are referred, or self-refer themselves, for a US breast examination. These studies are periodically repeated over the years, usually with an annual interval. US is carried out alone, or in combination with mammography, using advanced scanners equipped with wide band, high-frequency transducers. Facilities such as harmonic imaging, compound imaging, color-power Doppler imaging (now with new microvasculature techniques), elastography, trapezoid fields of view, and real-time extended field of view are available on all medium-to-high level US scanners and are employed by the operator basing on his/her preferences and on the specific clinical setting [1-3]. At the same time, in the last years chest US has become quite popular, also owing to the recent Covid-19 pandemic [4-11]. The normal pleural line is hyperechoic, thin (≤3 mm), and regular. The normally aerated lung slides below the pleural line, i.e., a shimmering motion of the pleural line can be normally appreciated [12]. Additionally, the air-filled lung usually shows A lines. The diaphragm and subdiaphragmatic anatomy, although visible during exhalation, are normally obscured during inspiration by the caudally moving aerated lung (curtain sign) [13]. The A lines are echogenic, gradually fading horizontal lines arranged at equal intervals below the pleural line, and represent the repetition artefact of the pleural surface [14]. The vertical reverberation artifact, or B lines, appear as continuous, well-defined and hyperechoic stripes, arising from the pleural line and spreading indeï¬nitely along the direction of the beam [15, 16]. Using a linear transducer, with a rectangular field of view, these B lines are parallel each other. Up to three of these vertical artifacts can be seen normally in a single intercostal scan. When the pulmonary interstitium thickens, due to edema or fibrosis, the B lines replace the normal A lines. Multiple B lines may be coalescent, eventually covering the entire area in case of severe disease (“white lung”).
While scanning women for breast US, we have frequently observed changes in the appearance of the pleural line or in the most superficial portion of the lung. The purpose of this study was to quantify the prevalence of pleuro-pulmonary changes in a population of asymptomatic women undergoing breast US. This may represent a unique opportunity of identifying previously unsuspected pleural and lung abnormalities.