Detection of parenchymal abnormalities in acute pyelonephritis by pulse inversion harmonic imaging with or without microbubble ultrasonographic contrast agent: correlation with computed tomography.

The purpose of this study was to evaluate the ability of pulse inversion harmonic imaging with or without microbubble ultrasonographic contrast agent in depicting renal parenchymal changes in acute pyelonephritis. The study population included 30 patients with acute pyelonephritis and 10 healthy volunteers. Pulse inversion harmonic imaging with or without contrast agent was compared with conventional ultrasonography and tissue harmonic imaging in terms of detection and conspicuity of renal abnormalities. The detection and conspicuity of renal parenchymal abnormalities in acute pyelonephritis on tissue harmonic imaging, pulse inversion harmonic imaging, and contrast-enhanced pulse inversion harmonic imaging were significantly better than those on conventional ultrasonography. In 2 of 10 healthy volunteers all 4 techniques yielded false-positive diagnoses of parenchymal abnormalities. In conclusion, tissue harmonic imaging and pulse inversion harmonic imaging are sensitive techniques for depicting renal parenchymal lesions in acute pyelonephritis. Despite relatively lower specificities and negative predictive values, these techniques are thought to be useful for the depiction of subtle parenchymal changes in acute pyelonephritis.