John Mark Ryan PhD, Presenter: Nothing to Disclose

Maria Bernadette Joyce MSc, Abstract Co-Author: Nothing to Disclose

Louise Ann Rainford PhD, Abstract Co-Author: Nothing to Disclose

Patrick C. Brennan PhD, Abstract Co-Author: Nothing to Disclose

Dual energy approaches to diagnostic imaging were introduced 2 decades ago and whilst little employment of this technique is evident in imaging clinics, a recent resurgence of interest is evident for chest, breast and absorbtiometry examinations. Little work however has been done to establish a rapid and cost-effective dual energy technique for visualisation of subtle soft tissue changes associated with foreign bodies. The current study addresses this deficiency and establishes a software-based, dual energy solution to enhance visualisation of soft tissue structures within the neck.

A cadaver was X-rayed using a MAXIRay 100 tube assembly. Lateral, horizontal projections of the neck were produced at source receptor distance of 180cm, using a direct digital, amorphous silicon flat-panel design image receptor, at 150kVp and 50kVp with an automatic exposure device. Using a novel software approach developed in-house, optimal soft-tissue images were created. The software was developed using the C++ language and FLTK library for display and interaction. On a pixel level, our algorithm works on the principle of adding the difference of the low-contrast from the high-contrast images, to the initial low-contrast image.

The results demonstrate effective removal of mandibular and vertebral details. When compared with non-subtracted images, enhanced visualisation of the anterior and posterior walls of the naso- and oro-pharynx, anterior and posterior walls of the larynx, epiglottis and other associated soft tissues was demonstrated. The production of subtracted images was instant with no additional user activity.

Whilst ultrasound and magnetic resonance imaging provides exquisite soft tissue detail, the current results offer a rapid and cost-effective alternative to these less-available modalities using open source software techniques and equipment available in most imaging centres.

Soft tissue visualisation is important for low contrast detail detection. An effective, software-based dual energy solution using non-specialised X-ray technology is proposed.

Ryan, J, Joyce, M, Rainford, L, Brennan, P, Enhanced Visualisation of Neck Soft Tissues Using a Software-based, Dual-energy Technique.  Radiological Society of North America 2007 Scientific Assembly and Annual Meeting, November 25 - November 30, 2007 ,Chicago IL. http://archive.rsna.org/2007/5010453.html