[Sun rays diaphragm: an ultrasonographic sign of interstitial involvement in the base of the lung].

Objectives: The purpose of this article is to present a new ultrasonographic sign: the spiculated diaphragm or sun rays diaphragm, that makes it possible to suspect disease in the base of the lung, generally involving the subpleural interstitium, during abdominal ultrasound examination.

Material And Methods: We present a study of seven patients in whom the diaphragm was observed as an echogenic, curvilinear, thickened image with numerous echogenic vertical lines or bands radiating from it posteriorly during abdominal ultrasound examination using a sectorial transducer. We have named this spiculated appearance of the diaphragm sun rays diaphragm. All patients underwent posteroanterior and lateral plain-film chest x-rays and high-resolution chest computed tomography (CT) with slices of the bases of the lungs.

Results: The chest pathology responsible for this finding was pulmonary fibrosis (n = 2), mitral valulopathy with heart failure (n = 2), unilateral atresia of the pulmonary vein (n = 1); combined miliary tuberculosis and Pneumocystis infection in an AIDS patient (n = 1), and carcinomatous lymphangitis (n = 1).

Conclusions: When a spiculated or sun rays diaphragm is observed during abdominal ultrasonography, disease involving the base of the lung (generally the subpleural interstitium) should be suspected; thus, in the absence of prior clinical knowledge of lung disease, additional examinations such as plain-film chest x-rays or thin slice chest CT should be performed.