Ring-down artifacts posterior to the right hemidiaphragm on abdominal sonography: sign of pulmonary parenchymal abnormalities.

Abstract

The aim of our study was to verify whether ring‐down artifacts posterior to the right hemidiaphragm on abdominal sonography reflected pulmonary parenchymal abnormalities. Forty patients (group 1) with abdominal diseases and 32 patients (group 2) with proved various pulmonary abnormalities involving the right lung base underwent abdominal sonography with 2‐4 MHz transducers. In these two groups, the presence and number of ring‐down artifacts were assessed and correlated with peridiaphragmatic lung findings on chest radiographs or computed tomographic scans. In 21 patients (group 3) with multiple (more than five) or numerous (10 or more) ring‐down artifacts, chest radiographs were reviewed to see if any peridiaphragmatic pulmonary abnormalities were present. In group 1, one or several (less than five) ring‐down artifacts were shown in 27 of 40 (68%) patients. In these patients, computed tomography showed insignificant focal intra‐ and interlobular septal thickening in the peridiaphragmatic right lung. In group 2, 31 of 32 (97%) patients showed multiple or numerous ring‐down artifacts. In group 3, chest radiographs showed various pulmonary abnormalities in 20 of 21 (95%) patients, including emphysema, idiopathic interstitial pneumonia, bronchopneumonia, and interstitial edema. Although nonspecific, ring‐down artifacts posterior to the right diaphragm on abdominal sonography may be used to predict pulmonary abnormalities when encountered on abdominal sonography in patients without specific pulmonary symptoms.

Transthoracic Sonography of Diffuse Parenchymal Lung Disease

“…6). In all control subjects (100%), comet tail artifacts HRCT, serologic tests (5); HRCT, serologic acute interstitial pneumonia (1) tests (8) Sarcoidosis (7) Sarcoidosis stage II (5); sarcoidosis stage III (2) Histologically established, HRCT (7) Acute viral pneumonia (6) Acute viral pneumonia (6) Histologically established, HRCT (3); BAL, HRCT, serologic tests (3) Lymphangitic carcinomatosis (6) Lymphangitic carcinomatosis due to established: Histologically established, HRCT (4); non-small-cell lung cancer (3); breast cancer (3) HRCT and progressive tumor disease (2) Silicosis (5) Silicosis (5) Histologically established, HRCT (3); history, typical chest radiographic findings and HRCT (2) Radiation pneumonitis (3) Radiation pneumonitis due to radiation after Typical history, BAL, HRCT (2); typical history, HRCT (1) non-small-cell lung cancer (3) were shown. Thirty (85.7%) of 35 subjects had only a few comet tail artifacts, with a strongly localized distribution (Fig.…”

“…Thickened subpleural interlobular septa, as well as ground-glass areas, as present in acute pulmonary edema, have been associated with the presence of comet tail artifacts. 6,7 In patients with diffuse alveolar-interstitial syndrome, multiple comet tail artifacts were found all over the lung surface, with a sensitivity of 93.4%. In the present study, almost all the patients with DPLD showed more than 6 comet tail artifacts per scan.…”

Physics of Diagnostic Ultrasound

“…In healthy adults these artifacts usually only arise at the last intercostal space above the diaphragm [6]. While performing ultrasound images of a liver, one may see multiple, vertical, long, narrow bands or lines extending down from the posterior surface of the right hemidiaphragm [9]. These are ring-down artifacts.…”

“…These artifacts appear as a solid streak or series of parallel bands radiating away from the gas. They occur from a large mismatch or large difference in acoustic impedance between two kinds of tissues, such as air and water [9]. When struck by an ultrasound pulse, the fluid is excited to ring or vibrate.…”

Transthoracic ultrasound for pleural effusion: traps and tricks

“…Such a large difference in acoustic impedance also creates artifactual images normally present in healthy subjects and defined reverberation artifacts: 1) the simple reverberations or lines A, are hyperechoic horizontal lines arranged in concentric bands below the pleural line; 2) the "comet tail" a few millimeters long (3-4 mm ) and typically with a triangular shape (hence the name "comet tail") and 3) the "ring-down " or B lines, or hyperechoic vertical lines, perpendicular to the pleural line and mobile with respiratory excursions, not triangular and with much longer tail than the comet. All these artifacts are usually and commonly present, to a lesser extent, even in normally aerated lung and are not pathological (24). These artifacts are also present even in the pneumonectomy space of patients undergoing pneumonectomy, according with the physical principles of ultrasounds, which are generated by the large difference in acoustic impedance between the superficial soft tissues of the rib cage and the air and fluid in the residual cavity after pneumonectomy (25).…”