Water-bath vs Direct Contact Ultrasound: A Randomized, Controlled, Blinded Image Review

• Published in: Academic emergency medicine 2003-05, Vol.10 (5), p.573-574
• Main Author: Leech, S. J
• Format: Article
• Language: English
• ISSN: 1069-6563; 1553-2712
• DOI: 10.1197/aemj.10.5.573-b

OBJECTIVES: To compare image detail, resolution and overall image quality of standard direct-contact (DC) ultrasound with a newly described water-bath evaluation technique (WET). METHODS: Matched images of ultrasound of avian tissue with imbedded wood and metallic foreign bodies were obtained by both DC and WET using a standard 38 mm (5-10MHz) linear transducer. Images of the index flexor tendon were obtained using both techniques. All studies were recorded on digital video with identical matching still images digitally captured through Final Cut Pro (Apple, INC). Images were cropped to blind image evaluators to which technique was used, excluding such identifiers as depth. 9 total matched still images including one identical control set were inserted into a Power Point presentation and reviewed by 4 emergency physicians experienced in emergency ultrasound. Evaluators rated each image with a 10-point Likert scale for image detail, resolution and overall image quality. Mean, paired t-test and p-values (p) were calculated. RESULTS: Mean scores for WET images in detail, resolution and image quality were: 8.028, 8.306, and 8.056 respectively. DC images for detail, resolution, and image quality were 7.81, 7.03, and 7.97 respectively. Resolution with WET scored statistically better with a p value = 0.027. Kappa values showed high inter-rater reliability. CONCLUSION: WET is equivalent in image detail, and quality to DC technique with minimal improvement in image resolution.