FM sonography in gallbladder disease: efficacy and comparison with conventional sonography

A new type of ultrasound signal processing ("FM sonography") appears to be beneficial compared to conventional ultrasound ("AM sonography") in some applications (e.g., diffuse liver disease and prostatic carcinoma). Despite these possible advantages, it is doubtful FM sonography will be widely used unless it is at least as useful as conventional (AM) sonography in all common applications. Fifty-five patients with suspected gallbladder disease were independently evaluated with both AM and FM sonography. The two modalities were blindly and prospectively compared for accuracy in detecting gallstones and for image quality. No statistically significant difference was found between images produced by FM and conventional signal processing. FM had an accuracy of detecting gallstones of 98.1%, compared to 96.2% for AM. Overall, FM accuracy was 97.7%, while AM had an overall accuracy of 97.3%. Other useful sonographic signs were evaluated (gallbladder wall thickness, diameter of common duct). No AM/FM difference was noted. Our data suggest that FM-only imaging could be performed in patients with suspected gallbladder disease without loss of accuracy.