Which of the following is not echogenic on ultrasonography-
Echoes are not produced if there is no difference in a tissue or between tissues. Homogenous fluids like blood, bile, urine, contents of simple cysts, ascites and pleural effusion are seen as echo-free structures. Ref : Physical principles of ultrasound (Dr Daniel J Bell and Ass. Pr. Mirjan M. Nadrljanski et al.)
Bile
Gas
Bone
Gall Stones
Fundamentals in Radiology