Utility of common bile duct measurements performed in right upper quadrant ultrasonography

Abstract

Study objectives: The usefulness of emergency medicine ultrasonography to facilitate the diagnosis of right upper quadrant (RUQ) pathology has been demonstrated in the literature. The ability to locate and measure the common bile duct (CBD) in RUQ ultrasonography can be a time-consuming and difficult process. We determine whether these additional data are necessary in the diagnosis of RUQ pathology. Methods: A retrospective review of all clinically indicated RUQ emergency medicine ultrasonographic examinations performed between September 2000 and September 2003 was conducted. All studies were performed by emergency medicine residents or attending physicians at a Level I university hospital and were subsequently confirmed with radiology, ultrasonography, computed tomographic imaging, or hepatobiliary 99mTc-iminodiacetic acid scans. Results: During a 36-month period, 684 clinically indicated emergency medicine RUQ ultrasonographic examinations were performed, with 276 confirmatory studies. RUQ pathology (cholelithiasis, gallbladder wall thickening >3 mm, pericholecystic fluid, CBD dilation >7 mm, or ultrasonographic Murphy's sign) was present in 99 (36%) of the 276 studies. Emergency physicians detected 77 of 99 confirmed positive cases, producing a sensitivity of 78% (95% confidence interval [CI] 0.71 to 0.84) and a specificity of 88% (95% CI 0.84 to 0.91). CBD dilation greater than 7 mm was confirmed in 12 (4%) of the 276 RUQ scans, leading to an incidence of 12% of all RUQ pathology. Emergency physicians correctly identified 5 of 12 (42%) dilated CBDs but recognized other RUQ pathology in 9 (75%) of these 12 cases. In the 12 cases of CBD dilation, 9 patients had elevations in liver function tests, total bilirubin, or gamma-glutamyl transferase. These values became more pronounced as the CBD increased in size. Furthermore, of the 276 clinically indicated studies, only 1 (0.03%) had isolated CBD dilatation (no stones, pericholecystic fluid, gallbladder wall thickening, or positive sonographic Murphy's sign), which was correctly recognized by the emergency physician. Review of this study showed that the RUQ scan was performed secondary to jaundice, and the patient was later revealed to have pancreatic cancer. Conclusion: Emergency physicians are quite accurate at diagnosing RUQ pathology by ultrasonography. The incidence of CBD dilatation is low in individuals with RUQ pathology. Furthermore, isolated CBD pathology is very rare, occurring 1 time in the 276 cases. Emergency medicine measurement of the CBD can be time consuming, difficult, and inaccurate. The diagnosis of RUQ pathology can be made frequently without the measurement of the CBD.