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

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.