Radiology, Vol 173, 117-121, Copyright © 1989 by Radiological Society of North America
In vitro dissolution of gallstones with MTBE: correlation with characteristics at CT and MR imaging
RL Baron, SJ Kuyper, SP Lee, CA Rohrmann Jr, WP Shuman and JA Nelson
Department of Radiology, University of Washington School of Medicine, Seattle 98195.
The authors undertook a study to determine whether in vitro computed
tomography (CT) or magnetic resonance (MR) imaging could enable the
prediction of the outcome of gallstone dissolution with methyl tert- butyl
ether (MTBE). In vitro CT and MR images were obtained of gallstones removed
at surgery from 40 and 30 patients, respectively. The patterns of the
gallstones seen on CT scans were categorized as dense, moderately dense,
faint, isodense, rimmed, and laminated. Gallstones were categorized by
maximal signal intensities seen on T1- weighted MR images. After imaging,
gallstones underwent in vitro MTBE dissolution. CT appearances correlated
well with dissolution rates. Greatest weight change was noted in gallstones
with homogeneously faint and isodense patterns, and least weight change was
seen in stones with a homogeneously dense pattern. Rimmed and laminated
stones with foci of high attenuation dissolved significantly to 5% or less
of the original weight, a finding indicating that such foci do not preclude
dissolution. Dissolution rates correlated with attenuation values of
homogeneous stones (r = .8) and of the rim portion of rimmed stones (r =
.8). No correlation was found between T1-weighted signal intensities on MR
images and MTBE dissolution rates.
