Real-time, 3-D ultrasound with multiple transducer arrays

Fifteen years of ultrasound guidance in regional anaesthesia: part 1

Ultrasound guidance for regional anaesthesia has gained enormous popularity in the past decade. The use of ultrasound guidance for many regional anaesthetic techniques is common in daily clinical practice, and the number of practitioners using it is increasing. However, alongside the enthusiasm, there should be a degree of informed scepticism. The widespread use of the various techniques of ultrasound-guided regional blocks without adequate training raises the danger of malpractice and subsequent impaired outcome. Adequate education in the use of regional block techniques under ultrasound guidance is essential. This review article addresses ultrasound guidance for regional anaesthesia, and is divided into two parts because of the size of the topic and the number of issues covered. This first part includes a review and preview of ultrasound guidance in regional anaesthesia and discusses all aspects of ultrasound for regional anaesthesia with a focus on recent technical developments, the positive implications in economics, further potential advantages (e.g. detection of anatomical variants, painless performance of blocks) and education. It also attempts to define a 'gold standard' in regional anaesthesia with the most recent findings in adequate volumes of local anaesthetics for peripheral nerve blocks. This standard should include an extraneural needle position, a high success rate, and wide application of ultrasound guidance in regional anaesthesia. The second part describes the impact of ultrasound on the development of nerve block techniques in the past 5 yr.

The ultrasound brain helmet: feasibility study of multiple simultaneous 3D scans of cerebral vasculature

We describe early stage experiments to test the feasibility of an ultrasound brain helmet to produce multiple simultaneous real-time three-dimensional (3D) scans of the cerebral vasculature from temporal and suboccipital acoustic windows of the skull. The transducer hardware and software of the Volumetrics Medical Imaging (Durham, NC, USA) real-time 3D scanner were modified to support dual 2.5 MHz matrix arrays of 256 transmit elements and 128 receive elements which produce two simultaneous 64 degrees pyramidal scans. The real-time display format consists of two coronal B-mode images merged into a 128 degrees sector, two simultaneous parasagittal images merged into a 128 degrees x 64 degrees C-mode plane and a simultaneous 64 degrees axial image. Real-time 3D color Doppler scans from a skull phantom with latex blood vessel were obtained after contrast agent injection as a proof of concept. The long-term goal is to produce real-time 3D ultrasound images of the cerebral vasculature from a portable unit capable of internet transmission thus enabling interactive 3D imaging, remote diagnosis and earlier therapeutic intervention. We are motivated by the urgency for rapid diagnosis of stroke due to the short time window of effective therapeutic intervention.