New and old ultrasound techniques

Table of Contents

Constantly evolving ultrasound techniques with the possibility for higher resolution using "harmonic imaging", elastography and contrast enhancement with contrast media are reasons for highlighting the situation.

After taking the patient history and physical examination, conventional B-mode and Colour Doppler imaging (CDI) are the imaging techniques of first choice in patients with suspected diseases of the liver and the gastrointestinal tract.

Unlike static CT scanning and magnetic resonance imaging (MRI) using contrast media, the ultrasound technique is real-time, fast, mobile and can easily be used to guide interventional procedures. In contrast to CT ultrasound uses no ionizing radiation, and is therefore also the technique of choice in pregnant women, and in patients with allergies against iodide based contrast media.

The diagnostic process, differential diagnosis and continuous routine follow-up of patients with for example focal liver lesions require an easily available, reliable and cost-effective diagnostic method. Ultrasound is a widely used method for the detection of liver lesions, but it was generally regarded as inferior to contrast-enhanced computed tomography and magnetic resonance imaging. Recent advances in contrast-enhanced ultrasound techniques (CEUS) have improved the detection rate to a level similar to that attained using CT and MRI. Owing to the high spatial resolution of sonography, CEUS may also detect subcentimetre metasta-ses. This is clear from several single centre studies and recently also a European multicentre study. Recently published reviews focus on the amazing advances of contrast enhanced ultra-sound with respect to detection and characterisation of focal liver lesions.

In recent years, also the use of endoscopic ultrasound has increased rapidly incorporating many new techniques and options, for example elastography, contrast enhanced techniques and new interventional options which will be standard procedures in the near future.

Endoscopic ultrasound, regarded as the "king discipline" of endoscopy, has been developed not only into an efficient and accurate diagnostic tool decisive in many clinical circumstances but also as a therapeutic option facilitating minimally invasive approaches to many organ systems. Guidance on the successful handling of needling and catheters has been established and other new EUS techniques are on the horizon showing the high potential of this method.

Published reviews and new textbooks which gather all current innovative methods and techniques suggest the possibility of incorporating this method into daily routine in a broader way than established so far. Insightful assessments of the evolving techniques and their uses and limitations are offered including comparison of methods.

There is also a need for teaching, such as step-by-step instructions for all current procedures and techniques including strategies for selecting patients and procedures including hygiene requirements, informed consent, patient positioning and monitoring. Logical, didactic tools including the necessary anatomy and pathology are mandatory including valuable tips and techniques for diagnosis and treatment to promote this method.

Prof Christoph F. Dietrich