Severe hydronephrosis may distort the appearance of the kidney. The kidney may be obstructed without hydronephrosis. Blunt or penetrating trauma Ultrasonography can aid in localizing the source of life-threatening hypotension. Fluid may accumulate in a number of anatomic spaces in the abdomen, including the pelvic, subphrenic, subhepatic, paracolic gutter, perinephric, and pleural spaces. Free fluid appears anechoic or dark without echos.
Clotted blood has a particulate, hypoechoic appearance.
Appendicitis The normal appendix is rarely seen. The wall of the appendix usually is no more than 6 mm thick. The normal appendix compresses when pressure is applied with the transducer. In acute appendicitis, wall thickness is 7 mm or more, and the appendix is noncompressible. It should be tender when palpated with the probe.