Ultrasound of the liver

Ultrasound contrast agents and contrast-specific imaging technology has greatly changed liver ultrasound. With contrast agents, ultrasound has become competitive with CT and MR imaging in lesion detection and may be even superior in lesion characterization and assessment of tumor viability following focal therapy. Moreover, ultrasound imaging maintains its advantage of being portable, inexpensive, and real time. Ultrasound contrast media are as critical in clinical practice as contrast media are for CT and MR imaging. The ability clearly to visualize vessels in solid tissue and distinguish vascular from nonvascular structures should make it easy to distinguish solid lesions from complex cysts, inflammation from abscess formation, hypervascular from hypovascular tumors, and so forth. With alteration in transmit power or intermittent imaging, image contrast can be manipulated to display vessels or tissue enhancement to highlight regions with different blood flow or fractional blood volume. These capabilities may prove superior to those of CT and MR imaging and will be available at the bedside or intraoperatively.