© Pol J Radiol, 2010; 75(3): 20-24 Material and Methods Ethical Committee of the Kerman University of Medical Sciences had approved the proposals and the study protocol. During an eight-month period, from July 2008 to March 2009, all male patients ‘with non- hepatobiliary problems’ referred to the Martyr Bahonar Medical Center of Kerman for ultra-sound (US) evaluation were asked to take part in the study. If their response was positive, a written con- sent was obtained and an abdominal US was performed, which included measurement of the liver span, spleen, por- tal vein, and CBD diameters as well as CBD wall thickness. The same radiologist performed all US tests. After completion of the imaging examinations, a nurse filled in a questionnaire regarding the addiction status, demographic parameters and exclusion criteria, question- ing the patient and/or his/her family members in a face-to- face manner. To increase the sample size, all asymptomatic family mem- bers of the participants were also invited to take part in the study. In order to blind the study, the radiologist was not informed on the patient’s addiction status – imaging stud- ies and measurements were performed before questioning the patient, so the radiologist was unaware of the subject’s addiction behavior. Inclusion criteria for the study group of addicts were as follows: • Age of 20 years or more. • Confirmed opium addiction for at least 1 year or more. • Regular opium use – at least twice a week. • Absence of any of the exclusion criteria. Inclusion criteria for the control group were the same, except for the addiction, which had to be inexistent. Exclusion criteria for both groups were as follows: • Heroin users or abusers of more potent opiate deriva- tives were excluded because of a more complex nature of their addiction. • Any symptoms of potential hepatobiliary disorders. • Any history of jaundice and/or hepatitis. • Any history of gallbladder illnesses. • Any kind of proved hemolytic anemia. • Any history of upper abdominal surgery and/or laparoscopy. • Any history of significant congenital anomalies. • History of frequent analgesic, sedative or anticholinergic drug consumption. After submission of a written consent, all patients under- went abdominal sonography by means of a Sonoline Siemna: Siemens GM-6600A2E200 sonomachine and Probe 3.5–5 Mega HZ. L40. All ultrasonographic studies were per- formed by the same radiologist. The procedure included: visualization of extrahepatic bile ducts and measurements of common bile duct caliber at its widest point. CBD wall Zahedi-Nejad N et al – Common Bile Duct (CBD) diameter… thickness, portal vein diameter, liver span at the midclavic- ular line, and spleen span in a window allowing for hilum visualization were also measured as extra parameters. The subjects were examined in the supine position, follow- ing a deep inspiration. At first, we measured the liver span in the parasagittal plane in the midclavicular line. This was followed by the measurements of the inner diameter of CBD and portal vein. To measure the CBD caliber we used the right anterior subcostal window in the longitudinal view and recorded the caliber at its widest point. After completion of the sonographic examination, a trained nurse administered a questionnaire containing questions on: demographic and addiction behaviors, history of past or cur- rent illnesses. Exclusion criteria were applied at this point. All data were collected in a database using SPSS ver.16. The data were analyzed with the use of the same software. Demographic data were included in the frequency tables, and mean values of measurements were compared using independent sample t-tests. P values of less than 0.05 were considered as statistically significant. Since in primary evaluations it seemed that the age of subjects and duration of addiction are important predictors, a multivariate analy- sis was performed in which CBD diameter and wall thick- ness were considered as dependent variables, while age, addiction, duration of addiction, and daily opium dose, as independent variables. Results A total of 343 subjects were originally invited to take part in the study. Forty-nine of them did not agree with the protocol, 9 patients had a history of upper abdominal surgery, 3 subjects were heroin abusers and 19 individuals were intermittent opium users. All of them were excluded from the study. The remaining 263 subject, including 121 opium addicts and 142 non-addict controls, remained for the analysis. Chief complaints (and the most frequent ones) were near- ly the same in both groups, i.e.: asthma, COPD, and car accidents. The common bile duct diameter showed a significant posi- tive correlation with the duration of opium addiction; the mean diameter of CBD was significantly higher in addicts than in non-addicts and the mean wall thicknesses value was significantly different in two groups. The habit of smoking cigarettes was significantly correlat- ed with the addiction. Multivariate analysis confirmed the associations found in the independent sample t-test. However, the latter test showed that both the age of the subjects and the duration of opium abuse have a strong correlation with CBD cali- ber and CBD wall thickness. Interestingly, the caliber of the CBD increases with increasing duration of the addiction (but only to the maximum of about 20 years, after which the CBD caliber gradually declines). 21