Abstract
Purpose :
Limited reports systematically characterize portable ultrasound devices, such as the Butterfly IQ (BiQ), in ocular imaging. In this study we compare the image resolution of the BiQ portable ultrasound with a conventional piezo-based ophthalmic ultrasound when scanning a phantom model. We hypothesize that the BiQ will perform as well as the conventional B-Scan ophthalmic ultrasound.
Methods :
Five BiQ imaging presets (MSK, MSK-Soft Tissue(MSK-ST), Nerve(N), Pediatric Lung(PL), and Ophthalmic(Ophtho)) were chosen and compared against the 10 MHz B-Scan probe on the Ellex Eye Cubed v3 ultrasound unit. Knox gelatin mixed with a gelatin:water ratio of 5:1 cast in a 5cm x 5cm x 2.5cm silicone mold was used as a phantom. Models contained a total of 6 paper stacks made of 3 paper sheets (1mm x 1mm x 0.1mm) with double-sided Scotch tape between layers to increase gap thickness in set increments as in Fig 1 (A, D). The BiQ was held parallel to the ground and scanned in a vertical pattern as in Fig 1 (B, E). The B-scan gain was set to 50 dB and the BIQ gain was set to 0 for MSK, 0 for MSK-ST, 0 for N, 20 for PL, and 0 for Ophtho. Calculated gap length was compared to image-based measurements, which were determined using ImageJ. Resolution was measured in ImageJ using the 1D brightness vs depth plot profile function as in Fig 1 (C, F). The derivative of the plot profile was used to create a slope function in order to determine the local minima, which corresponds to the position of peak brightness. The 1D linear distances were then measured between calculated slope minima of each peak.
Results :
The BiQ was less accurate than the Eye Cubed at measuring distances less than 200 microns. The Eye Cubed measured 0.19 +/- 0.00 mm while the butterfly had measurements of 0.39 +/- 0.06 mm(MSK), 0.30 +/- 0.04 mm(MSK-ST), 0.26 +/- 0.39 mm(PL), 0.39 +/- 0.04 mm(N), 0.26 +/- 0.07 mm(Ophtho) for the 1-layer molds. At distances greater than 200 microns (>2 layers of double-sided tape) the BiQ and Eye Cubed performed similarly.
Conclusions :
The BiQ demonstrates promising potential as a portable and less costly alternative to conventional piezo-based ophthalmic ultrasound machines in the evaluation of ophthalmic pathologies.
This is a 2021 ARVO Annual Meeting abstract.