A quantitative comparison of four current portable ultrasound bladder scanners

Summary 

Objective

Portable bladder ultrasound is a necessary investigation in urology and other disciplines. Scanners image with or without bladder wall detection—others provide only numeric readout. In volunteers, we compared measurements from four current scanners.

Methods

Bardscan, Verathon BVI3000, Verathon BVI6100 and Sonosite iLook15 were used with 28 healthy volunteers, with scanners in random order. Ordinary least squares regression modelled the measured volumes of each volunteer using each scanner. For each patient–scanner combination, the predicted volume from this model (corrected for the average bias of each scanner) represents the best estimate of the volume, and the difference between the measured bladder volume and the predicted volume was an estimate of the error of that measurement.

Results

The iLook15 and Bardscan underpredict, and the BVI3000 and BVI6100 overpredict, relative to the average of the four scanners (p<0.05). The BVI3000 had slightly greater error variability than the others (p=0.051). Measurement error appears more variable for larger volumes.

Conclusion

The two real-time imaging systems (the SonoSite iLook15 and the Bardscan) tended to give lower volume estimates than the two systems from the same manufacturer (the BVI3000 and BVI6100). Of the two BVI scanners, the 6100 had markedly less variable error.

Keywords: Post-void-residual, Portable ultrasound bladder scanner, Bladder voiding in volunteers, Bladder volume measurement