Scott J. Schulte

Biliary Sludge Is Formed by Modification of Hepatic Bile by the Gallbladder Mucosa

BACKGROUND & AIMS We studied 22 patients with symptomatic microlithiasis to determine whether a contributory role of the gallbladder in the early stage of cholesterol gallstone formation exists. We compared the merits of different methods (ultrasonography and microscopy) and sources (hepatic or gallbladder) of bile samples for diagnosing microlithiasis. METHODS Paired hepatic and gallbladder bile samples were studied with polarizing microscopy. Nucleation time, bile salts, phospholipid, cholesterol, cholesterol saturation index (CSI), bilirubin, total protein, albumin and mucin concentration were measured. All patients had abdominal ultrasound examination. RESULTS With polarizing microscopy as the standard, ultrasonography was positive in 13 patients (59%) and negative in 9 (41%). All gallbladder bile samples were positive for microlithiasis by microscopy. Only one hepatic bile sample was positive (P < .0001). There was a disproportional enrichment of total protein, albumin, and mucin (P < .05) in the gallbladder bile and a conversion of bilirubin diglucuronide to monoglucuronide (P < .01). Gallbladder samples had lower CSI but a faster nucleation time (P < .001), which correlates inversely with CSI, total protein, and mucin concentration. CONCLUSION Biochemical composition and physical chemical behavior of hepatic bile are modified during residence in the gallbladder, contributing to sludge formation. Gallbladder bile has a lower calculated CSI, higher deconjugation of bilirubin, protein and mucin concentration and crystals were present. Hepatic bile samples are inappropriate for microscopic detection of microlithiasis.

THE EFFECT OF STORAGE ON THE COMPUTED TOMOGRAPHY ATTENUATION OF GALLSTONES

RATIONALE AND OBJECTIVES.The effect of storage in five media on the computed tomography (CT) attenuation of gallstones, which might be important to future in vitro studies involving gallstones and their CT characteristics, was determined. METHODS.Gallstones were obtained in bile from cholecystectomy specimens. To establish a range of normal variability in the attenuation measurements of gallstones, 24 stones were scanned three times within a 5-minutc interval, with a comparison of the attenuation measurements of individual stones. To determine the effect of storage, five stones from the same gallbladder underwent CT within 48 hours of surgical retrieval and were then placed in native bile, sterile normal saline, sterile water, air, or formalin. The stones were rescanned after 1 week and 4 weeks in storage. Ten sets of five stones were evaluated with a comparison of the attenuation measurements of individual stones. RESULTS.There was an average difference of 10.2 Hounsfield Units (HU) and a maximum difference of 35 HU between the three attenuation measurements of the 24 stones that did not undergo storage. With storage, native bile was the only media where none of the 10 stones varied in attenuation by more than 35 HU. Air and saline had the greatest effect on the attenuation of stones with statistically significant differences after 4 weeks in storage (P<.02). Six of the stones stored in air and three stored in saline decreased in attenuation by more than 35 HU, with maximal decreases of 137 and 79 HU, respectively. Although not statistically significant, two stones in water and one stored in formalin showed more than 35 HU of attenuation change, varying by up to 69 and 47 HU, respectively. CONCLUSIONS.Storage may affect the CT attenuation of gallstones and needs to be considered in any in vitro experiment involving gallstones and CT correlation. Native bile is the only medium where no stones varied in attenuation more than can be accounted for by normal measurement variation, and thus, is the storage medium of choice.

Mechanical lithotripsy of large gallstones: correlation with CT characteristics

The CT characteristics of gallstones were correlated with mechanical forces required to fragment calculi in vitro. Forty-two gallstones > or = 11 mm in largest diameter were subjected to in vitro CT scanning and categorized as isodense, faint, laminated, rimmed, or dense as compared with saline. A mechanical lithotripter, attached to a dynamometer, was utilized simulating in vivo technique to accomplish lithotripsy. Significantly more force was required to fracture CT-dense (p < 0.02) and CT-rimmed (p < 0.05) gallstones than was required to fracture CT-isodense gallstones.

MR of focal liver lesions: Comparison of breath-hold and non-breath-hold rare and conventional spin-echo T2 weighted pulse sequences

To compare liver lesion detection rates, tissue signal and noise data, and qualitative parameters for breath-hold (BH) and non-breath-hold (NBH) hybrid rapid acquisition with relaxation enhancement (RARE) and conventional spin-echo (CSE) T2-weighted (CSE-T2) MR sequences, 20 patients were imaged using all three sequences. Lesion detection rates were 73.5% for the CSE-T2 sequence and 81.1% and 88.6% for the BH-RARE and NBH-RARE sequences, respectively (P = .027). Mean lesion-to-liver signal-difference-to-noise ratio for the NBH-RARE sequence was 14.0 +/- 11.5, significantly greater than 9.8 +/- 7.8 obtained for the BH-RARE sequence (P = .050) and 9.0 +/- 6.2 obtained for the CSE-T2 sequence (P = .015). The NBH-RARE sequence demonstrated fewer artifacts and greater overall image quality compared to the CSE-T2 sequence. The NBH-RARE sequence is a useful alternative to the liver signal-difference-to-noise ratio and lesion detection rate and better overall image quality.