Original Article Table 1. Demographic characteristics of the two groups. Table 2. A comparison of ultrasound findings between two groups. Age Height Weight Liver Span Spleen Span Portal Vein Diameter Common Bile Duct CBD Wall Thickness Addiction Addiction Yes No Yes No Yes No Yes No Yes No Yes No Yes No Yes No N 121 142 121 142 121 142 N 121 142 121 142 121 142 121 142 121 142 Mean 42.07 42.64 169.529 170.032 67.256 72.761 Mean 108.515 127.054 93.208 95.082 10.410 10.336 4.780 3.370 1.969 1.732 Std. deviation 11.564 15.784 8.2765 8.5839 12.8806 12.0070 Std. deviation 16.4992 15.4491 16.2909 14.2568 1.5935 1.4568 2.5827 2.2500 .6099 .6309 © Pol J Radiol, 2010; 75(3): 20-24 Std. error of the mean Statistical significance Std. error of the mean Statistical significance 1.051 1.325 .7524 .7203 1.1710 1.0076 1.4999 1.2965 1.4810 1.1964 .1449 .1222 .2348 .1888 .0554 .0529 .746 .631 .000 .000 .321 .694 .000 .002 Demographic parameters of the study subjects and controls were summarized in Table 1. Table 2 included ultrasonographic findings of the two groups and compared them. Figure 1 – demonstrated the correlation between CBD cali- ber and duration of addiction. Discussion Imaging textbooks have been presenting various values of the common bile duct caliber, depending on the method of measurement. Lower values were obtained in ultrasound imaging [13,14] while the higher ones in computed tomog- raphy scanning (CT-Scan) [15]. The values obtained by us were closer to the reported ultrasonic measurements. According to our knowledge, this is the first case-control study comparing biliary tract ultrasonographic results of opium addicts with the ones of non-addicts. At first glance, our results support previous reports regard- ing the dilating effects of opiates on the common bile duct. However, we found that this is the duration of opium abuse and not merely the presence of addiction which reveals the 22 Figure 1. Common bile duct caliber changes with increasing duration of addiction. highest correlation with CBD. The answer to the question “Are you addicted to opium” did not directly correlate with CBD caliber because the history of opium abuse was too short in our population and thus CBD had not enough time to become dilated in response to opium. Many reports con- cern very young populations living in Iran [16,17]. We hope that in the nearest future, studies will be including older populations as well.