In vitro CT evaluation of intrahepatic stones: correlation with chemical composition

• Published in: European journal of radiology Vol. 54; no. 2; pp. 258 - 263
• Main Authors: Kim, Young Jun, Han, Joon Koo, Jeong, Jun Yong, Lee, Kyoung Ho, Kim, Se Hyung, Kim, Young Il, Lee, Jeong Min, Choi, Byung Ihn, Park, Youn-Chan, Kim, Sun-Whe
• Format: Journal Article
• Language: English
• Published: Shannon Elsevier Ireland Ltd 01.05.2005; Elsevier Science
• Subjects: Adult; Aged; Aged, 80 and over; Bile duct, calculi; Bile duct, CT; Bilirubin - analysis; Biological and medical sciences; Calcium - analysis; Calculi - chemistry; Calculi - diagnostic imaging; Cholesterol - analysis; CT, experimental studies; Female; Humans; Image Processing, Computer-Assisted - methods; Investigative techniques, diagnostic techniques (general aspects); Liver Diseases - surgery; Liver, calculi; Liver, CT; Male; Medical sciences; Middle Aged; Phosphorus - analysis; Tomography, X-Ray Computed - methods; Liver, CT; Bile duct, CT; Liver, calculi; Bile duct, calculi; CT, experimental studies; Biliary tract; experimental studies; Nuclear medicine; Correlation; Calcium; Liver; Size; calculi; Liver; Bilirubin; Inorganic element; Interest; Chemical composition; Intrahepatic; Human; Radiodiagnosis; CT; Bile duct; CT; CT; Method; Experimental study; In vitro; Hand; Cholesterol; Lithiasis; Radiology; Medical imagery; Computerized axial tomography; calculi; Bile duct; Comparative study
• ISSN: 0720-048X; 1872-7727
• DOI: 10.1016/j.ejrad.2004.05.004

To describe in vitro CT features of intrahepatic stones and to correlate CT attenuation with chemical composition. Of the patients who underwent choledochoscopic intrahepatic stone removal between 1998 and 2001, 54 patients with stones larger than 3 mm were enrolled in this study. In each case, a chemical compositional analysis was performed to determine calcium, cholesterol, total bilirubin, and inorganic phosphorus compositions. The three largest stones obtained from each patient were imaged by CT. CT attenuation numbers were measured in the center images of each stone by drawing free-hand region of interest (ROI). The measured CT attenuation numbers were correlated with their chemical composition. Also, CT attenuation numbers of stones were compared with that of the liver on non-contrast CT (50–70 HU). Stone size ranged from 3.1 to 10.5 mm (mean ± S.D.: 6.0 ± 1.4). The CT attenuation numbers (HU) of stones ranged from 36.4 to 410.19 (mean ± S.D.: 94.6 ± 49.9). CT numbers of stones were below 70 HU in 11 patients (20.4%), and below 90 HU in 33 patients (59.3%). The chemical analysis data of the stones were as follows: calcium (0.5–6.5 wt.%; mean ± S.D., 2.6 ± 1.4), total bilirubin (0.45–24.4 wt.%; 13.1 ± 6.2), cholesterol (5.4–73.9 wt.%; 29.3 ± 17.4), phosphorus (0.1–1.2 wt.%; 0.6 ± 0.3), and non-soluble residue (17.6–85.4 wt.%; 57.0 ± 22.6). There was a weak but significant correlation between calcium composition and CT attenuation ( r = 0.38, P < 0.01) and no significant correlation between other chemical compositions and the CT attenuation (cholesterol, r = 0.01, P > 0.01; total bilirubin, r = 0.05, P > 0.01; phosphorus, r = 0.01, P > 0.01). On non-contrast CT, intrahepatic stones would not be hyperattenuating with respect to liver parenchyma in about one fifth of patients. The CT attenuation of stones correlates with calcium and does not correlate with any other chemical composition.