3460

Basic procedural knowledge of ultrasound contrast agents: Ahow to do DVD-ROM-based audiovisual teaching guideZoumpoulis PS, Pahos K, Theotokas I, Alexopoulos D, Tragea H,Schizas D, Korantzis A, Antsaklis A, Echonet: the UltrasoundNetwork www.echonet.gr, Greece; Hellenic Society for Ultrasound inMedicine and Biology, Greece

Objectives: To introduce ultrasound contrast agents. To survey thephysics and technology of US contrast agents and their role in ultra-sound. To present a step by step visual guide on how to prepare thepatient, how to administer the solution, how to make control, adjust-ments on US machine and how to evaluate the sonographic findings. Toestablish a safe and credible procedure that minimizes complicationsand ensures true positive results.Methods: Contrast enhanced Ultrasound improves detectability ofpathology by revealing regions of increased vascularity, which may betargeted selectively. This medical e-book is a multimedia DVD-ROMbased teaching file that illustrates the steps taken to perform an ultra-sound contrast agents exam. A detailed description of ultrasound con-trast agents, how to prepare the solution, how to prepare the patient,administration of the solution, control adjustments and sonographicappearance of USCA are provided in a user-friendly manner. Educa-tional double video presentations with the real time ultrasound examand the examiner’s technique.Results: A short historical review of the evolution of USCA is fol-lowed by a detailed presentation of the physics and technology ofrecent USCA.Conclusions: User-friendly DVD-Rom based visual guide with step bystep instructions on how to perform an ultrasound examination withUSCA.

3461

A cell-based graph-traversing approach for boundary detectionof sonographic breast lesionsCheng J-Z, Chen C-M, Chou Y-H, Institute of BiomedicalEngineering, National Taiwan University, Taiwan; Institute ofBiomedical Engineering, National Taiwan University, Taiwan;Department of Radiology, Taipei Veterans Hospital, Taiwan

A nearly automatic detection and segmentation algorithm for breastlesions in sonograms is proposed in this study. Watershed transform isfirst adopted to tessellate an image into catchment basins, which aredenominated as cells. A cell-based clustering mechanism, namely, cellcompetition algorithm, is proposed identify the prominent componentsconstituting a breast lesion. To extract the lesion boundary, an edge-based graph is constructed based on the result of the cell competitionalgorithm. A depth-first search scheme is developed to search out allthe candidate contours satisfying the property of dark-inside and bright-outside, which is a general property of breast lesions in US. Finally, wepick up several candidate contours according to the criteria of boundarysaliency and smoothness of the vicinity around boundary and proposethese most-likely contours to radiologist for selection. The proposedalgorithm can successfully captures the contours of lesions even withcomplex texture patterns.

3462

A 3D region competition algorithm for automatic estimation ofvascular indices of breast lesions on color Doppler imagesYeh F-C, Chen C-M, Chou Y-H, National Taiwan UniversityHospital, Taiwan; Institute of Biomedical Engineering, NationalTaiwan University, Taiwan; Department of Radiology, TaipeiVeterans Hospital, Taiwan

Vascular index (VI) is an important figure for differentiating malignantbreast lesions from benign ones. However, computing the VI of a breastlesion in a 3D sonogram is a labor-intensive task for the lack ofeffective segmentation scheme on 3D sonography. To facilitate auto-matic estimation of VI, in this paper, we propose a 3D segmentationalgorithm based on a two-region competition mechanism. A novelenergy function composed of 3D statistical and surface properties isdevised to guide deformation of boundary surface. Two types of vesselsare distinguished automatically in computing VI to avoid over-estima-tion. One is those vessels on the lesion surfaces and the other is thoseintruding into the lesions. It is shown that the VIs computed by theproposed algorithm are comparable to those estimated by manualdelineation. The correlation between the computed VIs and the malig-nancy of breast lesions is also evaluated.

3463

Ultrasound educational competency hierarchical outcomes: Areport on the novice ultrasound user, the first year medicalstudentBahner DP, Limperos RJ, The Ohio State University MedicalCenter, United States of America

Objectives: To examine the novice portion of the ultrasound compe-tency learning curve by exposing first year medical students to asynthesized ultrasound (US) hypotensive protocol.Methods: This prospective quasi-experimental intervention was per-formed at an accredited medical school with matriculating first yearmedical students. Each completed a pre and post intervention survey(Likert scale 1–10, 1 � neophyte, 10 � expert) that included questionsregarding comfort performing US exams and exposure to the field ofUS. Using a two-tailed student’s t-test, data compared pre and post-testlevels of comfort. A final practical exam was performed consisting ofthe hypotensive ultrasound protocol including eight images. Examswere graded for quality using a 10 item, four point scoring tool.Results: One hundred twenty-three medical students participated witha survey completion rate of 87.8%. Pre- and post-test comfort levelswere as follows: Basics of US 3.45, 7.05, (p � 0.01); acquiring 1.73,6.28, (p � 0.01); interpreting 1.76, 6.23, (p � 0.01); US anatomy 2.31,6.50, (p � 0.01). The average practical exam score was of 32.5 out of40; 102 (82.9%) students took the exam.Conclusions: This ultrasound intervention was designed to allow fur-ther understanding of the US competency curve. Medical students feeluncomfortable with US and minimal training can help them ascend thelearning curve.

3464

Acute abdomen in children: Diversity of diseases depends on ageLee J, Kim Y, Cho O-K, Koh B-H, Song SY, Hanyang UniversityHospital, Korea; Hanyang University Kuri Hospital, Korea

Acute pediatric abdomen is a very common clinical problem. Clinicaland laboratory findings, however, are nonspecific or confusing in manyinstances. This exhibit focuses on strategy in diagnosing acute pediatricabdomen depends on age. Age is a key factor in evaluating the cause;the incidence and symptoms of different conditions vary greatly overthe pediatric age spectrum. We divided pediatric age into three groups(before 1 year, 2 to 5 years, over 6 years). A variety of diseases arediscussed in this exhibit, such as before 1 year (intussusception, midgutvolvulus, incarcerated hernia, congenital biliary dilatation, gastroenter-itis), 2 to 5 years (appendicitis, mesenteric lymphadenitis, Henoch-Schonlein purpura, trauma), over 6 years (pancreatitis, cholecystitis,hemorrhagic ovarian cyst, ovarian torsion). Ultrasonography is essen-tial to ensure prompt management and can provide specific diagnoses.

P270 Ultrasound in Medicine and Biology Volume 32, Number 5S, 2006