The value of sonography in the assessment of cholecystolithotripsy.
To assess the reliability of ultrasound in measuring a minimum stone fragment burden we implanted radiolucent human gallstone fragments measuring from less than 1 mm up to 4 mm in size into the gallbladders of 12 domestic piglets.  Forty-eight hours later the fragments in each animal were assessed by a qualified radiologist using two different ultrasound machines in a randomized blinded fashion.  With regard to size estimation using a 5 MHz sector scanner, in two out of 12 examinations there was an overestimation of fragment size such that in a clinical setting an unneccessary repeat lithotripsy session would have been requested.  A 5 MHz linear array transducer was of sufficient reliability in all size estimations not to have resulted in such a request.  No gallbladder was falsely declared fragment free.  There were nonshadowing fragments present in five of 12 examinations using both transducers.  Clumping of small fragments less than or equal to 3 mm was present in two examinations.  We recommend that a second ultrasound examination is performed when the presence of clumping is suspected and also when a fragment-free gallbladder is initially diagnosed.
Department of Radiology, University of British Columbia, Vancouver, Canada.
S H
SH
Lee
F P
FP
McGrath
J
J
Zhou
H J
HJ
Burhenne
D000818:Animals; D002769:Cholelithiasis / Q000000981:diagnostic imaging* / Q000628:therapy; D006801:Humans; D008096:Lithotripsy; D013552:Swine; D014463:Ultrasonography / Q000379:methods