A randomised experiment comparing low-cost ultrasound gel alternative with commercial gel.

OBJECTIVE: Point-of-care ultrasound is a portable, relatively low-cost imaging modality with great potential utility in low-resource settings. However, commercially produced ultrasound gel is often cost-prohibitive and unavailable. We investigated whether images obtained using an alternative cornstarch-based gel would be of comparable quality with those using commercial gel. METHODS: This was a blinded, randomised, cross-over study comparing commercially produced ultrasound gel with home-made cornstarch-based gel. Ultrasound-trained faculty obtained three video clips with each gel type from patients at one urban ED. The clips were evaluated by a radiologist and an ultrasound-trained emergency physician. Images were assessed in terms of overall adequacy (dichotomous) and quality, resolution and detail using a rating scale (0-10). All sonographers and physicians reviewing the images were blinded to the type of gel used. RESULTS: Thirty-four patients were enrolled in the study, producing 204 separate images (102 with each gel). The cornstarch gel clips were deemed accurate in 70.6% (95% CI 63.9% to 76.5%) of the scans, as compared with 65.2% (95% CI 58.4% to 71.4%) of those using commercial gel. There was no difference between the two groups with respect to image detail, resolution or quality. CONCLUSIONS: Images produced using the cornstarch-based alternative ultrasound gel were of similar quality to those using commercial gel. The low cost and easy preparation of the cornstarch-based gel make it an attractive coupling medium for use in low-resource settings.

Evaluation of a cornstarch-based ultrasound gel alternative for low-resource settings.

BACKGROUND: Ultrasound is an ideal imaging modality for low-resource settings given its portability, ease of use, and wide range of applications. Commercially available ultrasound gels may be unavailable or cost prohibitive in low-resource settings. OBJECTIVE: Our aim was to investigate the quality of images obtained with an alternative ultrasound gel made from cornstarch and water in comparison with commercially available gel. METHODS: The cornstarch gel was made by heating water and cornstarch. The gel was used to obtain standard ultrasound images of the gallbladder, kidneys, bladder, heart, and neck vessels by the study investigators. Commercial gel was used as the control. Twenty-four ultrasound clips were shown to four blinded radiologists and two ultrasound-fellowship-trained emergency department physicians. They rated the images on adequacy (yes/no) and graded the images detail, resolution, and quality using a continuous 0-10 scale. RESULTS: A total of 144 video clips were shown to reviewers and 129 data-collection sheets were returned. There was no statistical difference in the proportion of images deemed to be of adequate quality: cornstarch-based gel = 0.97 (95% confidence interval [CI] 0.92-1.00) vs. commercially available gel = 0.85 (95% CI 0.75-0.94) (p = 0.053). The cornstarch gel was superior to commercial gel on all three image parameters: detail (p = 0.002), resolution (p = 0.018), and quality (p = 0.013). CONCLUSIONS: In this study, a gel made from cornstarch and water was an acceptable coupling medium and provided equally adequate images as compared with commercial ultrasound gel. This inexpensive gel made from ubiquitous materials can be an acceptable alternative to commercial gel in low-resource settings.