Prospective, randomized comparison of mechanical and electronic radial endoscopic ultrasound systems: assessment of performance parameters and image quality.
OBJECTIVE
Implementation of electronic image technology in endoscopic ultrasonography (EUS) should improve image quality, but systematic data are scarce. The purpose of this study was to compare the image quality and performance of an electronic and a mechanical radial echoendoscope.


MATERIAL AND METHODS
Eighty consecutive patients (42 M, mean age 56 years) in a tertiary referral center, without gross pathology (advanced tumors excluded), were prospectively randomized to EUS with the mechanical or electronic echoendoscope. Images from five standardized positions (pancreatobiliary and upper gastrointestinal (GI) tract) were taken by two examiners of differing experience. Time to acquire images was noted. Penetration depth was also measured. Image quality variables (overall quality, contrast, and structure discrimination) were assessed blindly on the basis of randomly shuffled images during three independent evaluations by the same experienced examiner (mean values were taken), using a visual analogue scale (VAS) from 1 (excellent) to 10 (inadequate).


RESULTS
Time needed to achieve visualization of the distal common bile duct (CBD) was significantly shorter with the electronic scope (49.7+/-8.6 versus 97.4+/-8.5 s; p<0.001). Image quality with the electronic scope was rated significantly better for all variables assessed, whereas EUS penetration depth was similar in both groups. There were no differences in examiner experience.


CONCLUSIONS
Electronic EUS provided better quality images according to the examiner's subjective assessment. An objective advantage was faster identification of the distal CBD.