Highlights of the development in ultrasound during the last 70 years: A historical review

This review looks at highlights of the development in ultrasound, ranging from interventional ultrasound and Doppler to the newest techniques like contrast-enhanced ultrasound and elastography, and gives reference to some of the valuable articles in Acta Radiologica. Ultrasound equipment is now available in any size and for any purpose, ranging from handheld devices to high-end devices, and the scientific societies include ultrasound professionals of all disciplines publishing guidelines and recommendations. Interventional ultrasound is expanding the field of use of ultrasound-guided interventions into nearly all specialties of medicine, from ultrasound guidance in minimally invasive robotic procedures to simple ultrasound-guided punctures performed by general practitioners. Each medical specialty is urged to define minimum requirements for equipment, education, training, and maintenance of skills, also for medical students. The clinical application of contrast-enhanced ultrasound and elastography is a topic often seen in current research settings.

Percutaneous Transhepatic External Biliary Drainage Utilizing a Pig Tail Balloon Catheter

A 2.3-mm soft pig tail balloon catheter was developed to be used for percutaneous transhepatic biliary drainage. A small balloon (OD 10 mm) secures an optimal internal fixation and side holes behind the balloon secure drainage of the cannulated bile duct peripheral to the balloon. Successful transhepatic biliary drainage with the pig tail balloon catheter was achieved in 11 of 12 patients for a period of 3 to 67 days (median 6 days). In one patient the catheter clogged after 55 days of drainage. No case of catheter dislodgement or other complications related to the external drainage was seen.

Failed percutaneous balloon dilation for renal access: Incidence and risk factors

OBJECTIVES

To present our experience using balloon dilation and discuss secondary techniques to establish a percutaneous tract when balloon dilation fails. Balloon dilation is a safe and effective method to achieve percutaneous renal access, but it is not uniformly successful. Also, the failure rate and risk factors have not been well documented.

METHODS

We retrospectively reviewed our last 99 consecutive percutaneous renal procedures using a balloon system as our initial dilation modality. In all cases, the urologist achieved needle access. We determined the balloon failure rate, relationship to prior renal surgery and other patient-related factors, and success rate using secondary techniques of tract dilation.

RESULTS

The balloon did not adequately dilate a tract in 17 (17% failure rate) of 99 cases. The risk factors for failure included a history of prior ipsilateral renal surgery (25% failure rate versus 8% without surgery) and subcostal compared with supracostal puncture (18% versus 9% failure rate). The failure rate was not increased when stratified by laterality, stone composition, stone size and location, or history of ipsilateral renal infection. Amplatz dilators were used in 16 refractory cases and were successful in 15. Metal Alken dilators were successfully used in 2 patients.

CONCLUSIONS

The balloon dilation system is commonly used as the primary modality to establish percutaneous renal access. Although safe and effective (83%), the success rate drops dramatically in patients with prior ipsilateral renal surgery. Knowledge and skill with alternative dilation systems, such as Amplatz or metal Alken dilators, are necessary to successfully gain entry into all renal collecting systems.

Interventional ultrasound in Europe

"Interventional ultrasound," defined as any diagnostic and therapeutic procedure performed under ultrasound guidance was first introduced in Europe, where its early development took place in Vienna, in Copenhagen, in Italy and in Switzerland. However, many of the applications of interventional ultrasound have been based on important pioneer work using other less-suitable needle guiding methods from the pre-ultrasound era. The European contributions to "interventional ultrasound" have especially been in the development of new puncture equipment, in the dissemination of various biopsy techniques, and draining procedures and, more recently, in the development of many different tissue-ablation techniques. The above contributions, which are outlined in this historical review, have, together with significant contributions from the rest of the world-not least from the United States and Japan-created a most efficient diagnostic as well as therapeutic tool for the benefit of our patients.

Interventional ultrasound

Interventional ultrasound, i.e., US-guided interventions, are diagnostic or therapeutic minimally invasive procedures guided by real-time ultrasound imaging, preferably using attachable needle steering devices. Guided fine- and coarse-needle biopsies of US-detectable abnormalities provide a firm basis for diagnosis and therapy. Multiple US-guided drainage and catheterization procedures such as nephrostomy, pleuracentesis, cholecystostomy, abscess drainage and central venous catheterization, etc., are rapid and safe alternatives to conventional drainage methods and open surgery. Devices and methods for US-guided minimally invasive focal tissue ablation are rapidly developing. Focal treatment of malignant tumours in the liver and prostate, using a variety of US-guided methods, are investigated. Complications of interventional ultrasound are reportedly low with a 0.19% overall complication rate and a 0.04% mortality rate. It is concluded that ultrasound provides a safe and cost-effective dynamic imaging modality for guidance of the increasing range of diagnostic and therapeutic interventional procedures.